linux/fs/btrfs/volumes.c
<<
>>
Prefs
   1/*
   2 * Copyright (C) 2007 Oracle.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18#include <linux/sched.h>
  19#include <linux/bio.h>
  20#include <linux/slab.h>
  21#include <linux/buffer_head.h>
  22#include <linux/blkdev.h>
  23#include <linux/random.h>
  24#include <linux/iocontext.h>
  25#include <linux/capability.h>
  26#include <linux/ratelimit.h>
  27#include <linux/kthread.h>
  28#include <asm/div64.h>
  29#include "compat.h"
  30#include "ctree.h"
  31#include "extent_map.h"
  32#include "disk-io.h"
  33#include "transaction.h"
  34#include "print-tree.h"
  35#include "volumes.h"
  36#include "async-thread.h"
  37#include "check-integrity.h"
  38#include "rcu-string.h"
  39
  40static int init_first_rw_device(struct btrfs_trans_handle *trans,
  41                                struct btrfs_root *root,
  42                                struct btrfs_device *device);
  43static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
  44static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
  45static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
  46
  47static DEFINE_MUTEX(uuid_mutex);
  48static LIST_HEAD(fs_uuids);
  49
  50static void lock_chunks(struct btrfs_root *root)
  51{
  52        mutex_lock(&root->fs_info->chunk_mutex);
  53}
  54
  55static void unlock_chunks(struct btrfs_root *root)
  56{
  57        mutex_unlock(&root->fs_info->chunk_mutex);
  58}
  59
  60static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
  61{
  62        struct btrfs_device *device;
  63        WARN_ON(fs_devices->opened);
  64        while (!list_empty(&fs_devices->devices)) {
  65                device = list_entry(fs_devices->devices.next,
  66                                    struct btrfs_device, dev_list);
  67                list_del(&device->dev_list);
  68                rcu_string_free(device->name);
  69                kfree(device);
  70        }
  71        kfree(fs_devices);
  72}
  73
  74void btrfs_cleanup_fs_uuids(void)
  75{
  76        struct btrfs_fs_devices *fs_devices;
  77
  78        while (!list_empty(&fs_uuids)) {
  79                fs_devices = list_entry(fs_uuids.next,
  80                                        struct btrfs_fs_devices, list);
  81                list_del(&fs_devices->list);
  82                free_fs_devices(fs_devices);
  83        }
  84}
  85
  86static noinline struct btrfs_device *__find_device(struct list_head *head,
  87                                                   u64 devid, u8 *uuid)
  88{
  89        struct btrfs_device *dev;
  90
  91        list_for_each_entry(dev, head, dev_list) {
  92                if (dev->devid == devid &&
  93                    (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
  94                        return dev;
  95                }
  96        }
  97        return NULL;
  98}
  99
 100static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 101{
 102        struct btrfs_fs_devices *fs_devices;
 103
 104        list_for_each_entry(fs_devices, &fs_uuids, list) {
 105                if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 106                        return fs_devices;
 107        }
 108        return NULL;
 109}
 110
 111static void requeue_list(struct btrfs_pending_bios *pending_bios,
 112                        struct bio *head, struct bio *tail)
 113{
 114
 115        struct bio *old_head;
 116
 117        old_head = pending_bios->head;
 118        pending_bios->head = head;
 119        if (pending_bios->tail)
 120                tail->bi_next = old_head;
 121        else
 122                pending_bios->tail = tail;
 123}
 124
 125/*
 126 * we try to collect pending bios for a device so we don't get a large
 127 * number of procs sending bios down to the same device.  This greatly
 128 * improves the schedulers ability to collect and merge the bios.
 129 *
 130 * But, it also turns into a long list of bios to process and that is sure
 131 * to eventually make the worker thread block.  The solution here is to
 132 * make some progress and then put this work struct back at the end of
 133 * the list if the block device is congested.  This way, multiple devices
 134 * can make progress from a single worker thread.
 135 */
 136static noinline void run_scheduled_bios(struct btrfs_device *device)
 137{
 138        struct bio *pending;
 139        struct backing_dev_info *bdi;
 140        struct btrfs_fs_info *fs_info;
 141        struct btrfs_pending_bios *pending_bios;
 142        struct bio *tail;
 143        struct bio *cur;
 144        int again = 0;
 145        unsigned long num_run;
 146        unsigned long batch_run = 0;
 147        unsigned long limit;
 148        unsigned long last_waited = 0;
 149        int force_reg = 0;
 150        int sync_pending = 0;
 151        struct blk_plug plug;
 152
 153        /*
 154         * this function runs all the bios we've collected for
 155         * a particular device.  We don't want to wander off to
 156         * another device without first sending all of these down.
 157         * So, setup a plug here and finish it off before we return
 158         */
 159        blk_start_plug(&plug);
 160
 161        bdi = blk_get_backing_dev_info(device->bdev);
 162        fs_info = device->dev_root->fs_info;
 163        limit = btrfs_async_submit_limit(fs_info);
 164        limit = limit * 2 / 3;
 165
 166loop:
 167        spin_lock(&device->io_lock);
 168
 169loop_lock:
 170        num_run = 0;
 171
 172        /* take all the bios off the list at once and process them
 173         * later on (without the lock held).  But, remember the
 174         * tail and other pointers so the bios can be properly reinserted
 175         * into the list if we hit congestion
 176         */
 177        if (!force_reg && device->pending_sync_bios.head) {
 178                pending_bios = &device->pending_sync_bios;
 179                force_reg = 1;
 180        } else {
 181                pending_bios = &device->pending_bios;
 182                force_reg = 0;
 183        }
 184
 185        pending = pending_bios->head;
 186        tail = pending_bios->tail;
 187        WARN_ON(pending && !tail);
 188
 189        /*
 190         * if pending was null this time around, no bios need processing
 191         * at all and we can stop.  Otherwise it'll loop back up again
 192         * and do an additional check so no bios are missed.
 193         *
 194         * device->running_pending is used to synchronize with the
 195         * schedule_bio code.
 196         */
 197        if (device->pending_sync_bios.head == NULL &&
 198            device->pending_bios.head == NULL) {
 199                again = 0;
 200                device->running_pending = 0;
 201        } else {
 202                again = 1;
 203                device->running_pending = 1;
 204        }
 205
 206        pending_bios->head = NULL;
 207        pending_bios->tail = NULL;
 208
 209        spin_unlock(&device->io_lock);
 210
 211        while (pending) {
 212
 213                rmb();
 214                /* we want to work on both lists, but do more bios on the
 215                 * sync list than the regular list
 216                 */
 217                if ((num_run > 32 &&
 218                    pending_bios != &device->pending_sync_bios &&
 219                    device->pending_sync_bios.head) ||
 220                   (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 221                    device->pending_bios.head)) {
 222                        spin_lock(&device->io_lock);
 223                        requeue_list(pending_bios, pending, tail);
 224                        goto loop_lock;
 225                }
 226
 227                cur = pending;
 228                pending = pending->bi_next;
 229                cur->bi_next = NULL;
 230
 231                if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 232                    waitqueue_active(&fs_info->async_submit_wait))
 233                        wake_up(&fs_info->async_submit_wait);
 234
 235                BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 236
 237                /*
 238                 * if we're doing the sync list, record that our
 239                 * plug has some sync requests on it
 240                 *
 241                 * If we're doing the regular list and there are
 242                 * sync requests sitting around, unplug before
 243                 * we add more
 244                 */
 245                if (pending_bios == &device->pending_sync_bios) {
 246                        sync_pending = 1;
 247                } else if (sync_pending) {
 248                        blk_finish_plug(&plug);
 249                        blk_start_plug(&plug);
 250                        sync_pending = 0;
 251                }
 252
 253                btrfsic_submit_bio(cur->bi_rw, cur);
 254                num_run++;
 255                batch_run++;
 256                if (need_resched())
 257                        cond_resched();
 258
 259                /*
 260                 * we made progress, there is more work to do and the bdi
 261                 * is now congested.  Back off and let other work structs
 262                 * run instead
 263                 */
 264                if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 265                    fs_info->fs_devices->open_devices > 1) {
 266                        struct io_context *ioc;
 267
 268                        ioc = current->io_context;
 269
 270                        /*
 271                         * the main goal here is that we don't want to
 272                         * block if we're going to be able to submit
 273                         * more requests without blocking.
 274                         *
 275                         * This code does two great things, it pokes into
 276                         * the elevator code from a filesystem _and_
 277                         * it makes assumptions about how batching works.
 278                         */
 279                        if (ioc && ioc->nr_batch_requests > 0 &&
 280                            time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 281                            (last_waited == 0 ||
 282                             ioc->last_waited == last_waited)) {
 283                                /*
 284                                 * we want to go through our batch of
 285                                 * requests and stop.  So, we copy out
 286                                 * the ioc->last_waited time and test
 287                                 * against it before looping
 288                                 */
 289                                last_waited = ioc->last_waited;
 290                                if (need_resched())
 291                                        cond_resched();
 292                                continue;
 293                        }
 294                        spin_lock(&device->io_lock);
 295                        requeue_list(pending_bios, pending, tail);
 296                        device->running_pending = 1;
 297
 298                        spin_unlock(&device->io_lock);
 299                        btrfs_requeue_work(&device->work);
 300                        goto done;
 301                }
 302                /* unplug every 64 requests just for good measure */
 303                if (batch_run % 64 == 0) {
 304                        blk_finish_plug(&plug);
 305                        blk_start_plug(&plug);
 306                        sync_pending = 0;
 307                }
 308        }
 309
 310        cond_resched();
 311        if (again)
 312                goto loop;
 313
 314        spin_lock(&device->io_lock);
 315        if (device->pending_bios.head || device->pending_sync_bios.head)
 316                goto loop_lock;
 317        spin_unlock(&device->io_lock);
 318
 319done:
 320        blk_finish_plug(&plug);
 321}
 322
 323static void pending_bios_fn(struct btrfs_work *work)
 324{
 325        struct btrfs_device *device;
 326
 327        device = container_of(work, struct btrfs_device, work);
 328        run_scheduled_bios(device);
 329}
 330
 331static noinline int device_list_add(const char *path,
 332                           struct btrfs_super_block *disk_super,
 333                           u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 334{
 335        struct btrfs_device *device;
 336        struct btrfs_fs_devices *fs_devices;
 337        struct rcu_string *name;
 338        u64 found_transid = btrfs_super_generation(disk_super);
 339
 340        fs_devices = find_fsid(disk_super->fsid);
 341        if (!fs_devices) {
 342                fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 343                if (!fs_devices)
 344                        return -ENOMEM;
 345                INIT_LIST_HEAD(&fs_devices->devices);
 346                INIT_LIST_HEAD(&fs_devices->alloc_list);
 347                list_add(&fs_devices->list, &fs_uuids);
 348                memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 349                fs_devices->latest_devid = devid;
 350                fs_devices->latest_trans = found_transid;
 351                mutex_init(&fs_devices->device_list_mutex);
 352                device = NULL;
 353        } else {
 354                device = __find_device(&fs_devices->devices, devid,
 355                                       disk_super->dev_item.uuid);
 356        }
 357        if (!device) {
 358                if (fs_devices->opened)
 359                        return -EBUSY;
 360
 361                device = kzalloc(sizeof(*device), GFP_NOFS);
 362                if (!device) {
 363                        /* we can safely leave the fs_devices entry around */
 364                        return -ENOMEM;
 365                }
 366                device->devid = devid;
 367                device->dev_stats_valid = 0;
 368                device->work.func = pending_bios_fn;
 369                memcpy(device->uuid, disk_super->dev_item.uuid,
 370                       BTRFS_UUID_SIZE);
 371                spin_lock_init(&device->io_lock);
 372
 373                name = rcu_string_strdup(path, GFP_NOFS);
 374                if (!name) {
 375                        kfree(device);
 376                        return -ENOMEM;
 377                }
 378                rcu_assign_pointer(device->name, name);
 379                INIT_LIST_HEAD(&device->dev_alloc_list);
 380
 381                /* init readahead state */
 382                spin_lock_init(&device->reada_lock);
 383                device->reada_curr_zone = NULL;
 384                atomic_set(&device->reada_in_flight, 0);
 385                device->reada_next = 0;
 386                INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
 387                INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
 388
 389                mutex_lock(&fs_devices->device_list_mutex);
 390                list_add_rcu(&device->dev_list, &fs_devices->devices);
 391                mutex_unlock(&fs_devices->device_list_mutex);
 392
 393                device->fs_devices = fs_devices;
 394                fs_devices->num_devices++;
 395        } else if (!device->name || strcmp(device->name->str, path)) {
 396                name = rcu_string_strdup(path, GFP_NOFS);
 397                if (!name)
 398                        return -ENOMEM;
 399                rcu_string_free(device->name);
 400                rcu_assign_pointer(device->name, name);
 401                if (device->missing) {
 402                        fs_devices->missing_devices--;
 403                        device->missing = 0;
 404                }
 405        }
 406
 407        if (found_transid > fs_devices->latest_trans) {
 408                fs_devices->latest_devid = devid;
 409                fs_devices->latest_trans = found_transid;
 410        }
 411        *fs_devices_ret = fs_devices;
 412        return 0;
 413}
 414
 415static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 416{
 417        struct btrfs_fs_devices *fs_devices;
 418        struct btrfs_device *device;
 419        struct btrfs_device *orig_dev;
 420
 421        fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 422        if (!fs_devices)
 423                return ERR_PTR(-ENOMEM);
 424
 425        INIT_LIST_HEAD(&fs_devices->devices);
 426        INIT_LIST_HEAD(&fs_devices->alloc_list);
 427        INIT_LIST_HEAD(&fs_devices->list);
 428        mutex_init(&fs_devices->device_list_mutex);
 429        fs_devices->latest_devid = orig->latest_devid;
 430        fs_devices->latest_trans = orig->latest_trans;
 431        fs_devices->total_devices = orig->total_devices;
 432        memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 433
 434        /* We have held the volume lock, it is safe to get the devices. */
 435        list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 436                struct rcu_string *name;
 437
 438                device = kzalloc(sizeof(*device), GFP_NOFS);
 439                if (!device)
 440                        goto error;
 441
 442                /*
 443                 * This is ok to do without rcu read locked because we hold the
 444                 * uuid mutex so nothing we touch in here is going to disappear.
 445                 */
 446                name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 447                if (!name) {
 448                        kfree(device);
 449                        goto error;
 450                }
 451                rcu_assign_pointer(device->name, name);
 452
 453                device->devid = orig_dev->devid;
 454                device->work.func = pending_bios_fn;
 455                memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
 456                spin_lock_init(&device->io_lock);
 457                INIT_LIST_HEAD(&device->dev_list);
 458                INIT_LIST_HEAD(&device->dev_alloc_list);
 459
 460                list_add(&device->dev_list, &fs_devices->devices);
 461                device->fs_devices = fs_devices;
 462                fs_devices->num_devices++;
 463        }
 464        return fs_devices;
 465error:
 466        free_fs_devices(fs_devices);
 467        return ERR_PTR(-ENOMEM);
 468}
 469
 470void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 471{
 472        struct btrfs_device *device, *next;
 473
 474        struct block_device *latest_bdev = NULL;
 475        u64 latest_devid = 0;
 476        u64 latest_transid = 0;
 477
 478        mutex_lock(&uuid_mutex);
 479again:
 480        /* This is the initialized path, it is safe to release the devices. */
 481        list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 482                if (device->in_fs_metadata) {
 483                        if (!latest_transid ||
 484                            device->generation > latest_transid) {
 485                                latest_devid = device->devid;
 486                                latest_transid = device->generation;
 487                                latest_bdev = device->bdev;
 488                        }
 489                        continue;
 490                }
 491
 492                if (device->bdev) {
 493                        blkdev_put(device->bdev, device->mode);
 494                        device->bdev = NULL;
 495                        fs_devices->open_devices--;
 496                }
 497                if (device->writeable) {
 498                        list_del_init(&device->dev_alloc_list);
 499                        device->writeable = 0;
 500                        fs_devices->rw_devices--;
 501                }
 502                list_del_init(&device->dev_list);
 503                fs_devices->num_devices--;
 504                rcu_string_free(device->name);
 505                kfree(device);
 506        }
 507
 508        if (fs_devices->seed) {
 509                fs_devices = fs_devices->seed;
 510                goto again;
 511        }
 512
 513        fs_devices->latest_bdev = latest_bdev;
 514        fs_devices->latest_devid = latest_devid;
 515        fs_devices->latest_trans = latest_transid;
 516
 517        mutex_unlock(&uuid_mutex);
 518}
 519
 520static void __free_device(struct work_struct *work)
 521{
 522        struct btrfs_device *device;
 523
 524        device = container_of(work, struct btrfs_device, rcu_work);
 525
 526        if (device->bdev)
 527                blkdev_put(device->bdev, device->mode);
 528
 529        rcu_string_free(device->name);
 530        kfree(device);
 531}
 532
 533static void free_device(struct rcu_head *head)
 534{
 535        struct btrfs_device *device;
 536
 537        device = container_of(head, struct btrfs_device, rcu);
 538
 539        INIT_WORK(&device->rcu_work, __free_device);
 540        schedule_work(&device->rcu_work);
 541}
 542
 543static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 544{
 545        struct btrfs_device *device;
 546
 547        if (--fs_devices->opened > 0)
 548                return 0;
 549
 550        mutex_lock(&fs_devices->device_list_mutex);
 551        list_for_each_entry(device, &fs_devices->devices, dev_list) {
 552                struct btrfs_device *new_device;
 553                struct rcu_string *name;
 554
 555                if (device->bdev)
 556                        fs_devices->open_devices--;
 557
 558                if (device->writeable) {
 559                        list_del_init(&device->dev_alloc_list);
 560                        fs_devices->rw_devices--;
 561                }
 562
 563                if (device->can_discard)
 564                        fs_devices->num_can_discard--;
 565
 566                new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 567                BUG_ON(!new_device); /* -ENOMEM */
 568                memcpy(new_device, device, sizeof(*new_device));
 569
 570                /* Safe because we are under uuid_mutex */
 571                if (device->name) {
 572                        name = rcu_string_strdup(device->name->str, GFP_NOFS);
 573                        BUG_ON(device->name && !name); /* -ENOMEM */
 574                        rcu_assign_pointer(new_device->name, name);
 575                }
 576                new_device->bdev = NULL;
 577                new_device->writeable = 0;
 578                new_device->in_fs_metadata = 0;
 579                new_device->can_discard = 0;
 580                list_replace_rcu(&device->dev_list, &new_device->dev_list);
 581
 582                call_rcu(&device->rcu, free_device);
 583        }
 584        mutex_unlock(&fs_devices->device_list_mutex);
 585
 586        WARN_ON(fs_devices->open_devices);
 587        WARN_ON(fs_devices->rw_devices);
 588        fs_devices->opened = 0;
 589        fs_devices->seeding = 0;
 590
 591        return 0;
 592}
 593
 594int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 595{
 596        struct btrfs_fs_devices *seed_devices = NULL;
 597        int ret;
 598
 599        mutex_lock(&uuid_mutex);
 600        ret = __btrfs_close_devices(fs_devices);
 601        if (!fs_devices->opened) {
 602                seed_devices = fs_devices->seed;
 603                fs_devices->seed = NULL;
 604        }
 605        mutex_unlock(&uuid_mutex);
 606
 607        while (seed_devices) {
 608                fs_devices = seed_devices;
 609                seed_devices = fs_devices->seed;
 610                __btrfs_close_devices(fs_devices);
 611                free_fs_devices(fs_devices);
 612        }
 613        return ret;
 614}
 615
 616static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 617                                fmode_t flags, void *holder)
 618{
 619        struct request_queue *q;
 620        struct block_device *bdev;
 621        struct list_head *head = &fs_devices->devices;
 622        struct btrfs_device *device;
 623        struct block_device *latest_bdev = NULL;
 624        struct buffer_head *bh;
 625        struct btrfs_super_block *disk_super;
 626        u64 latest_devid = 0;
 627        u64 latest_transid = 0;
 628        u64 devid;
 629        int seeding = 1;
 630        int ret = 0;
 631
 632        flags |= FMODE_EXCL;
 633
 634        list_for_each_entry(device, head, dev_list) {
 635                if (device->bdev)
 636                        continue;
 637                if (!device->name)
 638                        continue;
 639
 640                bdev = blkdev_get_by_path(device->name->str, flags, holder);
 641                if (IS_ERR(bdev)) {
 642                        printk(KERN_INFO "btrfs: open %s failed\n", device->name->str);
 643                        goto error;
 644                }
 645                filemap_write_and_wait(bdev->bd_inode->i_mapping);
 646                invalidate_bdev(bdev);
 647                set_blocksize(bdev, 4096);
 648
 649                bh = btrfs_read_dev_super(bdev);
 650                if (!bh)
 651                        goto error_close;
 652
 653                disk_super = (struct btrfs_super_block *)bh->b_data;
 654                devid = btrfs_stack_device_id(&disk_super->dev_item);
 655                if (devid != device->devid)
 656                        goto error_brelse;
 657
 658                if (memcmp(device->uuid, disk_super->dev_item.uuid,
 659                           BTRFS_UUID_SIZE))
 660                        goto error_brelse;
 661
 662                device->generation = btrfs_super_generation(disk_super);
 663                if (!latest_transid || device->generation > latest_transid) {
 664                        latest_devid = devid;
 665                        latest_transid = device->generation;
 666                        latest_bdev = bdev;
 667                }
 668
 669                if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 670                        device->writeable = 0;
 671                } else {
 672                        device->writeable = !bdev_read_only(bdev);
 673                        seeding = 0;
 674                }
 675
 676                q = bdev_get_queue(bdev);
 677                if (blk_queue_discard(q)) {
 678                        device->can_discard = 1;
 679                        fs_devices->num_can_discard++;
 680                }
 681
 682                device->bdev = bdev;
 683                device->in_fs_metadata = 0;
 684                device->mode = flags;
 685
 686                if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 687                        fs_devices->rotating = 1;
 688
 689                fs_devices->open_devices++;
 690                if (device->writeable) {
 691                        fs_devices->rw_devices++;
 692                        list_add(&device->dev_alloc_list,
 693                                 &fs_devices->alloc_list);
 694                }
 695                brelse(bh);
 696                continue;
 697
 698error_brelse:
 699                brelse(bh);
 700error_close:
 701                blkdev_put(bdev, flags);
 702error:
 703                continue;
 704        }
 705        if (fs_devices->open_devices == 0) {
 706                ret = -EINVAL;
 707                goto out;
 708        }
 709        fs_devices->seeding = seeding;
 710        fs_devices->opened = 1;
 711        fs_devices->latest_bdev = latest_bdev;
 712        fs_devices->latest_devid = latest_devid;
 713        fs_devices->latest_trans = latest_transid;
 714        fs_devices->total_rw_bytes = 0;
 715out:
 716        return ret;
 717}
 718
 719int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 720                       fmode_t flags, void *holder)
 721{
 722        int ret;
 723
 724        mutex_lock(&uuid_mutex);
 725        if (fs_devices->opened) {
 726                fs_devices->opened++;
 727                ret = 0;
 728        } else {
 729                ret = __btrfs_open_devices(fs_devices, flags, holder);
 730        }
 731        mutex_unlock(&uuid_mutex);
 732        return ret;
 733}
 734
 735int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 736                          struct btrfs_fs_devices **fs_devices_ret)
 737{
 738        struct btrfs_super_block *disk_super;
 739        struct block_device *bdev;
 740        struct buffer_head *bh;
 741        int ret;
 742        u64 devid;
 743        u64 transid;
 744        u64 total_devices;
 745
 746        flags |= FMODE_EXCL;
 747        bdev = blkdev_get_by_path(path, flags, holder);
 748
 749        if (IS_ERR(bdev)) {
 750                ret = PTR_ERR(bdev);
 751                goto error;
 752        }
 753
 754        mutex_lock(&uuid_mutex);
 755        ret = set_blocksize(bdev, 4096);
 756        if (ret)
 757                goto error_close;
 758        bh = btrfs_read_dev_super(bdev);
 759        if (!bh) {
 760                ret = -EINVAL;
 761                goto error_close;
 762        }
 763        disk_super = (struct btrfs_super_block *)bh->b_data;
 764        devid = btrfs_stack_device_id(&disk_super->dev_item);
 765        transid = btrfs_super_generation(disk_super);
 766        total_devices = btrfs_super_num_devices(disk_super);
 767        if (disk_super->label[0])
 768                printk(KERN_INFO "device label %s ", disk_super->label);
 769        else
 770                printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
 771        printk(KERN_CONT "devid %llu transid %llu %s\n",
 772               (unsigned long long)devid, (unsigned long long)transid, path);
 773        ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 774        if (!ret && fs_devices_ret)
 775                (*fs_devices_ret)->total_devices = total_devices;
 776        brelse(bh);
 777error_close:
 778        mutex_unlock(&uuid_mutex);
 779        blkdev_put(bdev, flags);
 780error:
 781        return ret;
 782}
 783
 784/* helper to account the used device space in the range */
 785int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
 786                                   u64 end, u64 *length)
 787{
 788        struct btrfs_key key;
 789        struct btrfs_root *root = device->dev_root;
 790        struct btrfs_dev_extent *dev_extent;
 791        struct btrfs_path *path;
 792        u64 extent_end;
 793        int ret;
 794        int slot;
 795        struct extent_buffer *l;
 796
 797        *length = 0;
 798
 799        if (start >= device->total_bytes)
 800                return 0;
 801
 802        path = btrfs_alloc_path();
 803        if (!path)
 804                return -ENOMEM;
 805        path->reada = 2;
 806
 807        key.objectid = device->devid;
 808        key.offset = start;
 809        key.type = BTRFS_DEV_EXTENT_KEY;
 810
 811        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 812        if (ret < 0)
 813                goto out;
 814        if (ret > 0) {
 815                ret = btrfs_previous_item(root, path, key.objectid, key.type);
 816                if (ret < 0)
 817                        goto out;
 818        }
 819
 820        while (1) {
 821                l = path->nodes[0];
 822                slot = path->slots[0];
 823                if (slot >= btrfs_header_nritems(l)) {
 824                        ret = btrfs_next_leaf(root, path);
 825                        if (ret == 0)
 826                                continue;
 827                        if (ret < 0)
 828                                goto out;
 829
 830                        break;
 831                }
 832                btrfs_item_key_to_cpu(l, &key, slot);
 833
 834                if (key.objectid < device->devid)
 835                        goto next;
 836
 837                if (key.objectid > device->devid)
 838                        break;
 839
 840                if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 841                        goto next;
 842
 843                dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 844                extent_end = key.offset + btrfs_dev_extent_length(l,
 845                                                                  dev_extent);
 846                if (key.offset <= start && extent_end > end) {
 847                        *length = end - start + 1;
 848                        break;
 849                } else if (key.offset <= start && extent_end > start)
 850                        *length += extent_end - start;
 851                else if (key.offset > start && extent_end <= end)
 852                        *length += extent_end - key.offset;
 853                else if (key.offset > start && key.offset <= end) {
 854                        *length += end - key.offset + 1;
 855                        break;
 856                } else if (key.offset > end)
 857                        break;
 858
 859next:
 860                path->slots[0]++;
 861        }
 862        ret = 0;
 863out:
 864        btrfs_free_path(path);
 865        return ret;
 866}
 867
 868/*
 869 * find_free_dev_extent - find free space in the specified device
 870 * @device:     the device which we search the free space in
 871 * @num_bytes:  the size of the free space that we need
 872 * @start:      store the start of the free space.
 873 * @len:        the size of the free space. that we find, or the size of the max
 874 *              free space if we don't find suitable free space
 875 *
 876 * this uses a pretty simple search, the expectation is that it is
 877 * called very infrequently and that a given device has a small number
 878 * of extents
 879 *
 880 * @start is used to store the start of the free space if we find. But if we
 881 * don't find suitable free space, it will be used to store the start position
 882 * of the max free space.
 883 *
 884 * @len is used to store the size of the free space that we find.
 885 * But if we don't find suitable free space, it is used to store the size of
 886 * the max free space.
 887 */
 888int find_free_dev_extent(struct btrfs_device *device, u64 num_bytes,
 889                         u64 *start, u64 *len)
 890{
 891        struct btrfs_key key;
 892        struct btrfs_root *root = device->dev_root;
 893        struct btrfs_dev_extent *dev_extent;
 894        struct btrfs_path *path;
 895        u64 hole_size;
 896        u64 max_hole_start;
 897        u64 max_hole_size;
 898        u64 extent_end;
 899        u64 search_start;
 900        u64 search_end = device->total_bytes;
 901        int ret;
 902        int slot;
 903        struct extent_buffer *l;
 904
 905        /* FIXME use last free of some kind */
 906
 907        /* we don't want to overwrite the superblock on the drive,
 908         * so we make sure to start at an offset of at least 1MB
 909         */
 910        search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 911
 912        max_hole_start = search_start;
 913        max_hole_size = 0;
 914        hole_size = 0;
 915
 916        if (search_start >= search_end) {
 917                ret = -ENOSPC;
 918                goto error;
 919        }
 920
 921        path = btrfs_alloc_path();
 922        if (!path) {
 923                ret = -ENOMEM;
 924                goto error;
 925        }
 926        path->reada = 2;
 927
 928        key.objectid = device->devid;
 929        key.offset = search_start;
 930        key.type = BTRFS_DEV_EXTENT_KEY;
 931
 932        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 933        if (ret < 0)
 934                goto out;
 935        if (ret > 0) {
 936                ret = btrfs_previous_item(root, path, key.objectid, key.type);
 937                if (ret < 0)
 938                        goto out;
 939        }
 940
 941        while (1) {
 942                l = path->nodes[0];
 943                slot = path->slots[0];
 944                if (slot >= btrfs_header_nritems(l)) {
 945                        ret = btrfs_next_leaf(root, path);
 946                        if (ret == 0)
 947                                continue;
 948                        if (ret < 0)
 949                                goto out;
 950
 951                        break;
 952                }
 953                btrfs_item_key_to_cpu(l, &key, slot);
 954
 955                if (key.objectid < device->devid)
 956                        goto next;
 957
 958                if (key.objectid > device->devid)
 959                        break;
 960
 961                if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
 962                        goto next;
 963
 964                if (key.offset > search_start) {
 965                        hole_size = key.offset - search_start;
 966
 967                        if (hole_size > max_hole_size) {
 968                                max_hole_start = search_start;
 969                                max_hole_size = hole_size;
 970                        }
 971
 972                        /*
 973                         * If this free space is greater than which we need,
 974                         * it must be the max free space that we have found
 975                         * until now, so max_hole_start must point to the start
 976                         * of this free space and the length of this free space
 977                         * is stored in max_hole_size. Thus, we return
 978                         * max_hole_start and max_hole_size and go back to the
 979                         * caller.
 980                         */
 981                        if (hole_size >= num_bytes) {
 982                                ret = 0;
 983                                goto out;
 984                        }
 985                }
 986
 987                dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 988                extent_end = key.offset + btrfs_dev_extent_length(l,
 989                                                                  dev_extent);
 990                if (extent_end > search_start)
 991                        search_start = extent_end;
 992next:
 993                path->slots[0]++;
 994                cond_resched();
 995        }
 996
 997        /*
 998         * At this point, search_start should be the end of
 999         * allocated dev extents, and when shrinking the device,
1000         * search_end may be smaller than search_start.
1001         */
1002        if (search_end > search_start)
1003                hole_size = search_end - search_start;
1004
1005        if (hole_size > max_hole_size) {
1006                max_hole_start = search_start;
1007                max_hole_size = hole_size;
1008        }
1009
1010        /* See above. */
1011        if (hole_size < num_bytes)
1012                ret = -ENOSPC;
1013        else
1014                ret = 0;
1015
1016out:
1017        btrfs_free_path(path);
1018error:
1019        *start = max_hole_start;
1020        if (len)
1021                *len = max_hole_size;
1022        return ret;
1023}
1024
1025static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1026                          struct btrfs_device *device,
1027                          u64 start)
1028{
1029        int ret;
1030        struct btrfs_path *path;
1031        struct btrfs_root *root = device->dev_root;
1032        struct btrfs_key key;
1033        struct btrfs_key found_key;
1034        struct extent_buffer *leaf = NULL;
1035        struct btrfs_dev_extent *extent = NULL;
1036
1037        path = btrfs_alloc_path();
1038        if (!path)
1039                return -ENOMEM;
1040
1041        key.objectid = device->devid;
1042        key.offset = start;
1043        key.type = BTRFS_DEV_EXTENT_KEY;
1044again:
1045        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1046        if (ret > 0) {
1047                ret = btrfs_previous_item(root, path, key.objectid,
1048                                          BTRFS_DEV_EXTENT_KEY);
1049                if (ret)
1050                        goto out;
1051                leaf = path->nodes[0];
1052                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1053                extent = btrfs_item_ptr(leaf, path->slots[0],
1054                                        struct btrfs_dev_extent);
1055                BUG_ON(found_key.offset > start || found_key.offset +
1056                       btrfs_dev_extent_length(leaf, extent) < start);
1057                key = found_key;
1058                btrfs_release_path(path);
1059                goto again;
1060        } else if (ret == 0) {
1061                leaf = path->nodes[0];
1062                extent = btrfs_item_ptr(leaf, path->slots[0],
1063                                        struct btrfs_dev_extent);
1064        } else {
1065                btrfs_error(root->fs_info, ret, "Slot search failed");
1066                goto out;
1067        }
1068
1069        if (device->bytes_used > 0) {
1070                u64 len = btrfs_dev_extent_length(leaf, extent);
1071                device->bytes_used -= len;
1072                spin_lock(&root->fs_info->free_chunk_lock);
1073                root->fs_info->free_chunk_space += len;
1074                spin_unlock(&root->fs_info->free_chunk_lock);
1075        }
1076        ret = btrfs_del_item(trans, root, path);
1077        if (ret) {
1078                btrfs_error(root->fs_info, ret,
1079                            "Failed to remove dev extent item");
1080        }
1081out:
1082        btrfs_free_path(path);
1083        return ret;
1084}
1085
1086int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1087                           struct btrfs_device *device,
1088                           u64 chunk_tree, u64 chunk_objectid,
1089                           u64 chunk_offset, u64 start, u64 num_bytes)
1090{
1091        int ret;
1092        struct btrfs_path *path;
1093        struct btrfs_root *root = device->dev_root;
1094        struct btrfs_dev_extent *extent;
1095        struct extent_buffer *leaf;
1096        struct btrfs_key key;
1097
1098        WARN_ON(!device->in_fs_metadata);
1099        path = btrfs_alloc_path();
1100        if (!path)
1101                return -ENOMEM;
1102
1103        key.objectid = device->devid;
1104        key.offset = start;
1105        key.type = BTRFS_DEV_EXTENT_KEY;
1106        ret = btrfs_insert_empty_item(trans, root, path, &key,
1107                                      sizeof(*extent));
1108        if (ret)
1109                goto out;
1110
1111        leaf = path->nodes[0];
1112        extent = btrfs_item_ptr(leaf, path->slots[0],
1113                                struct btrfs_dev_extent);
1114        btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1115        btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1116        btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1117
1118        write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1119                    (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
1120                    BTRFS_UUID_SIZE);
1121
1122        btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1123        btrfs_mark_buffer_dirty(leaf);
1124out:
1125        btrfs_free_path(path);
1126        return ret;
1127}
1128
1129static noinline int find_next_chunk(struct btrfs_root *root,
1130                                    u64 objectid, u64 *offset)
1131{
1132        struct btrfs_path *path;
1133        int ret;
1134        struct btrfs_key key;
1135        struct btrfs_chunk *chunk;
1136        struct btrfs_key found_key;
1137
1138        path = btrfs_alloc_path();
1139        if (!path)
1140                return -ENOMEM;
1141
1142        key.objectid = objectid;
1143        key.offset = (u64)-1;
1144        key.type = BTRFS_CHUNK_ITEM_KEY;
1145
1146        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1147        if (ret < 0)
1148                goto error;
1149
1150        BUG_ON(ret == 0); /* Corruption */
1151
1152        ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
1153        if (ret) {
1154                *offset = 0;
1155        } else {
1156                btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1157                                      path->slots[0]);
1158                if (found_key.objectid != objectid)
1159                        *offset = 0;
1160                else {
1161                        chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
1162                                               struct btrfs_chunk);
1163                        *offset = found_key.offset +
1164                                btrfs_chunk_length(path->nodes[0], chunk);
1165                }
1166        }
1167        ret = 0;
1168error:
1169        btrfs_free_path(path);
1170        return ret;
1171}
1172
1173static noinline int find_next_devid(struct btrfs_root *root, u64 *objectid)
1174{
1175        int ret;
1176        struct btrfs_key key;
1177        struct btrfs_key found_key;
1178        struct btrfs_path *path;
1179
1180        root = root->fs_info->chunk_root;
1181
1182        path = btrfs_alloc_path();
1183        if (!path)
1184                return -ENOMEM;
1185
1186        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1187        key.type = BTRFS_DEV_ITEM_KEY;
1188        key.offset = (u64)-1;
1189
1190        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1191        if (ret < 0)
1192                goto error;
1193
1194        BUG_ON(ret == 0); /* Corruption */
1195
1196        ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
1197                                  BTRFS_DEV_ITEM_KEY);
1198        if (ret) {
1199                *objectid = 1;
1200        } else {
1201                btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1202                                      path->slots[0]);
1203                *objectid = found_key.offset + 1;
1204        }
1205        ret = 0;
1206error:
1207        btrfs_free_path(path);
1208        return ret;
1209}
1210
1211/*
1212 * the device information is stored in the chunk root
1213 * the btrfs_device struct should be fully filled in
1214 */
1215int btrfs_add_device(struct btrfs_trans_handle *trans,
1216                     struct btrfs_root *root,
1217                     struct btrfs_device *device)
1218{
1219        int ret;
1220        struct btrfs_path *path;
1221        struct btrfs_dev_item *dev_item;
1222        struct extent_buffer *leaf;
1223        struct btrfs_key key;
1224        unsigned long ptr;
1225
1226        root = root->fs_info->chunk_root;
1227
1228        path = btrfs_alloc_path();
1229        if (!path)
1230                return -ENOMEM;
1231
1232        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1233        key.type = BTRFS_DEV_ITEM_KEY;
1234        key.offset = device->devid;
1235
1236        ret = btrfs_insert_empty_item(trans, root, path, &key,
1237                                      sizeof(*dev_item));
1238        if (ret)
1239                goto out;
1240
1241        leaf = path->nodes[0];
1242        dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1243
1244        btrfs_set_device_id(leaf, dev_item, device->devid);
1245        btrfs_set_device_generation(leaf, dev_item, 0);
1246        btrfs_set_device_type(leaf, dev_item, device->type);
1247        btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1248        btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1249        btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1250        btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1251        btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1252        btrfs_set_device_group(leaf, dev_item, 0);
1253        btrfs_set_device_seek_speed(leaf, dev_item, 0);
1254        btrfs_set_device_bandwidth(leaf, dev_item, 0);
1255        btrfs_set_device_start_offset(leaf, dev_item, 0);
1256
1257        ptr = (unsigned long)btrfs_device_uuid(dev_item);
1258        write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1259        ptr = (unsigned long)btrfs_device_fsid(dev_item);
1260        write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1261        btrfs_mark_buffer_dirty(leaf);
1262
1263        ret = 0;
1264out:
1265        btrfs_free_path(path);
1266        return ret;
1267}
1268
1269static int btrfs_rm_dev_item(struct btrfs_root *root,
1270                             struct btrfs_device *device)
1271{
1272        int ret;
1273        struct btrfs_path *path;
1274        struct btrfs_key key;
1275        struct btrfs_trans_handle *trans;
1276
1277        root = root->fs_info->chunk_root;
1278
1279        path = btrfs_alloc_path();
1280        if (!path)
1281                return -ENOMEM;
1282
1283        trans = btrfs_start_transaction(root, 0);
1284        if (IS_ERR(trans)) {
1285                btrfs_free_path(path);
1286                return PTR_ERR(trans);
1287        }
1288        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1289        key.type = BTRFS_DEV_ITEM_KEY;
1290        key.offset = device->devid;
1291        lock_chunks(root);
1292
1293        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1294        if (ret < 0)
1295                goto out;
1296
1297        if (ret > 0) {
1298                ret = -ENOENT;
1299                goto out;
1300        }
1301
1302        ret = btrfs_del_item(trans, root, path);
1303        if (ret)
1304                goto out;
1305out:
1306        btrfs_free_path(path);
1307        unlock_chunks(root);
1308        btrfs_commit_transaction(trans, root);
1309        return ret;
1310}
1311
1312int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1313{
1314        struct btrfs_device *device;
1315        struct btrfs_device *next_device;
1316        struct block_device *bdev;
1317        struct buffer_head *bh = NULL;
1318        struct btrfs_super_block *disk_super;
1319        struct btrfs_fs_devices *cur_devices;
1320        u64 all_avail;
1321        u64 devid;
1322        u64 num_devices;
1323        u8 *dev_uuid;
1324        int ret = 0;
1325        bool clear_super = false;
1326
1327        mutex_lock(&uuid_mutex);
1328
1329        all_avail = root->fs_info->avail_data_alloc_bits |
1330                root->fs_info->avail_system_alloc_bits |
1331                root->fs_info->avail_metadata_alloc_bits;
1332
1333        if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
1334            root->fs_info->fs_devices->num_devices <= 4) {
1335                printk(KERN_ERR "btrfs: unable to go below four devices "
1336                       "on raid10\n");
1337                ret = -EINVAL;
1338                goto out;
1339        }
1340
1341        if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
1342            root->fs_info->fs_devices->num_devices <= 2) {
1343                printk(KERN_ERR "btrfs: unable to go below two "
1344                       "devices on raid1\n");
1345                ret = -EINVAL;
1346                goto out;
1347        }
1348
1349        if (strcmp(device_path, "missing") == 0) {
1350                struct list_head *devices;
1351                struct btrfs_device *tmp;
1352
1353                device = NULL;
1354                devices = &root->fs_info->fs_devices->devices;
1355                /*
1356                 * It is safe to read the devices since the volume_mutex
1357                 * is held.
1358                 */
1359                list_for_each_entry(tmp, devices, dev_list) {
1360                        if (tmp->in_fs_metadata && !tmp->bdev) {
1361                                device = tmp;
1362                                break;
1363                        }
1364                }
1365                bdev = NULL;
1366                bh = NULL;
1367                disk_super = NULL;
1368                if (!device) {
1369                        printk(KERN_ERR "btrfs: no missing devices found to "
1370                               "remove\n");
1371                        goto out;
1372                }
1373        } else {
1374                bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
1375                                          root->fs_info->bdev_holder);
1376                if (IS_ERR(bdev)) {
1377                        ret = PTR_ERR(bdev);
1378                        goto out;
1379                }
1380
1381                set_blocksize(bdev, 4096);
1382                invalidate_bdev(bdev);
1383                bh = btrfs_read_dev_super(bdev);
1384                if (!bh) {
1385                        ret = -EINVAL;
1386                        goto error_close;
1387                }
1388                disk_super = (struct btrfs_super_block *)bh->b_data;
1389                devid = btrfs_stack_device_id(&disk_super->dev_item);
1390                dev_uuid = disk_super->dev_item.uuid;
1391                device = btrfs_find_device(root, devid, dev_uuid,
1392                                           disk_super->fsid);
1393                if (!device) {
1394                        ret = -ENOENT;
1395                        goto error_brelse;
1396                }
1397        }
1398
1399        if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1400                printk(KERN_ERR "btrfs: unable to remove the only writeable "
1401                       "device\n");
1402                ret = -EINVAL;
1403                goto error_brelse;
1404        }
1405
1406        if (device->writeable) {
1407                lock_chunks(root);
1408                list_del_init(&device->dev_alloc_list);
1409                unlock_chunks(root);
1410                root->fs_info->fs_devices->rw_devices--;
1411                clear_super = true;
1412        }
1413
1414        ret = btrfs_shrink_device(device, 0);
1415        if (ret)
1416                goto error_undo;
1417
1418        ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1419        if (ret)
1420                goto error_undo;
1421
1422        spin_lock(&root->fs_info->free_chunk_lock);
1423        root->fs_info->free_chunk_space = device->total_bytes -
1424                device->bytes_used;
1425        spin_unlock(&root->fs_info->free_chunk_lock);
1426
1427        device->in_fs_metadata = 0;
1428        btrfs_scrub_cancel_dev(root, device);
1429
1430        /*
1431         * the device list mutex makes sure that we don't change
1432         * the device list while someone else is writing out all
1433         * the device supers.
1434         */
1435
1436        cur_devices = device->fs_devices;
1437        mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1438        list_del_rcu(&device->dev_list);
1439
1440        device->fs_devices->num_devices--;
1441        device->fs_devices->total_devices--;
1442
1443        if (device->missing)
1444                root->fs_info->fs_devices->missing_devices--;
1445
1446        next_device = list_entry(root->fs_info->fs_devices->devices.next,
1447                                 struct btrfs_device, dev_list);
1448        if (device->bdev == root->fs_info->sb->s_bdev)
1449                root->fs_info->sb->s_bdev = next_device->bdev;
1450        if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1451                root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1452
1453        if (device->bdev)
1454                device->fs_devices->open_devices--;
1455
1456        call_rcu(&device->rcu, free_device);
1457        mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1458
1459        num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1460        btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1461
1462        if (cur_devices->open_devices == 0) {
1463                struct btrfs_fs_devices *fs_devices;
1464                fs_devices = root->fs_info->fs_devices;
1465                while (fs_devices) {
1466                        if (fs_devices->seed == cur_devices)
1467                                break;
1468                        fs_devices = fs_devices->seed;
1469                }
1470                fs_devices->seed = cur_devices->seed;
1471                cur_devices->seed = NULL;
1472                lock_chunks(root);
1473                __btrfs_close_devices(cur_devices);
1474                unlock_chunks(root);
1475                free_fs_devices(cur_devices);
1476        }
1477
1478        root->fs_info->num_tolerated_disk_barrier_failures =
1479                btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1480
1481        /*
1482         * at this point, the device is zero sized.  We want to
1483         * remove it from the devices list and zero out the old super
1484         */
1485        if (clear_super) {
1486                /* make sure this device isn't detected as part of
1487                 * the FS anymore
1488                 */
1489                memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1490                set_buffer_dirty(bh);
1491                sync_dirty_buffer(bh);
1492        }
1493
1494        ret = 0;
1495
1496error_brelse:
1497        brelse(bh);
1498error_close:
1499        if (bdev)
1500                blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1501out:
1502        mutex_unlock(&uuid_mutex);
1503        return ret;
1504error_undo:
1505        if (device->writeable) {
1506                lock_chunks(root);
1507                list_add(&device->dev_alloc_list,
1508                         &root->fs_info->fs_devices->alloc_list);
1509                unlock_chunks(root);
1510                root->fs_info->fs_devices->rw_devices++;
1511        }
1512        goto error_brelse;
1513}
1514
1515/*
1516 * does all the dirty work required for changing file system's UUID.
1517 */
1518static int btrfs_prepare_sprout(struct btrfs_root *root)
1519{
1520        struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
1521        struct btrfs_fs_devices *old_devices;
1522        struct btrfs_fs_devices *seed_devices;
1523        struct btrfs_super_block *disk_super = root->fs_info->super_copy;
1524        struct btrfs_device *device;
1525        u64 super_flags;
1526
1527        BUG_ON(!mutex_is_locked(&uuid_mutex));
1528        if (!fs_devices->seeding)
1529                return -EINVAL;
1530
1531        seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
1532        if (!seed_devices)
1533                return -ENOMEM;
1534
1535        old_devices = clone_fs_devices(fs_devices);
1536        if (IS_ERR(old_devices)) {
1537                kfree(seed_devices);
1538                return PTR_ERR(old_devices);
1539        }
1540
1541        list_add(&old_devices->list, &fs_uuids);
1542
1543        memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
1544        seed_devices->opened = 1;
1545        INIT_LIST_HEAD(&seed_devices->devices);
1546        INIT_LIST_HEAD(&seed_devices->alloc_list);
1547        mutex_init(&seed_devices->device_list_mutex);
1548
1549        mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1550        list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
1551                              synchronize_rcu);
1552        mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1553
1554        list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
1555        list_for_each_entry(device, &seed_devices->devices, dev_list) {
1556                device->fs_devices = seed_devices;
1557        }
1558
1559        fs_devices->seeding = 0;
1560        fs_devices->num_devices = 0;
1561        fs_devices->open_devices = 0;
1562        fs_devices->total_devices = 0;
1563        fs_devices->seed = seed_devices;
1564
1565        generate_random_uuid(fs_devices->fsid);
1566        memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1567        memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1568        super_flags = btrfs_super_flags(disk_super) &
1569                      ~BTRFS_SUPER_FLAG_SEEDING;
1570        btrfs_set_super_flags(disk_super, super_flags);
1571
1572        return 0;
1573}
1574
1575/*
1576 * strore the expected generation for seed devices in device items.
1577 */
1578static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
1579                               struct btrfs_root *root)
1580{
1581        struct btrfs_path *path;
1582        struct extent_buffer *leaf;
1583        struct btrfs_dev_item *dev_item;
1584        struct btrfs_device *device;
1585        struct btrfs_key key;
1586        u8 fs_uuid[BTRFS_UUID_SIZE];
1587        u8 dev_uuid[BTRFS_UUID_SIZE];
1588        u64 devid;
1589        int ret;
1590
1591        path = btrfs_alloc_path();
1592        if (!path)
1593                return -ENOMEM;
1594
1595        root = root->fs_info->chunk_root;
1596        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1597        key.offset = 0;
1598        key.type = BTRFS_DEV_ITEM_KEY;
1599
1600        while (1) {
1601                ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1602                if (ret < 0)
1603                        goto error;
1604
1605                leaf = path->nodes[0];
1606next_slot:
1607                if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1608                        ret = btrfs_next_leaf(root, path);
1609                        if (ret > 0)
1610                                break;
1611                        if (ret < 0)
1612                                goto error;
1613                        leaf = path->nodes[0];
1614                        btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1615                        btrfs_release_path(path);
1616                        continue;
1617                }
1618
1619                btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1620                if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
1621                    key.type != BTRFS_DEV_ITEM_KEY)
1622                        break;
1623
1624                dev_item = btrfs_item_ptr(leaf, path->slots[0],
1625                                          struct btrfs_dev_item);
1626                devid = btrfs_device_id(leaf, dev_item);
1627                read_extent_buffer(leaf, dev_uuid,
1628                                   (unsigned long)btrfs_device_uuid(dev_item),
1629                                   BTRFS_UUID_SIZE);
1630                read_extent_buffer(leaf, fs_uuid,
1631                                   (unsigned long)btrfs_device_fsid(dev_item),
1632                                   BTRFS_UUID_SIZE);
1633                device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
1634                BUG_ON(!device); /* Logic error */
1635
1636                if (device->fs_devices->seeding) {
1637                        btrfs_set_device_generation(leaf, dev_item,
1638                                                    device->generation);
1639                        btrfs_mark_buffer_dirty(leaf);
1640                }
1641
1642                path->slots[0]++;
1643                goto next_slot;
1644        }
1645        ret = 0;
1646error:
1647        btrfs_free_path(path);
1648        return ret;
1649}
1650
1651int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
1652{
1653        struct request_queue *q;
1654        struct btrfs_trans_handle *trans;
1655        struct btrfs_device *device;
1656        struct block_device *bdev;
1657        struct list_head *devices;
1658        struct super_block *sb = root->fs_info->sb;
1659        struct rcu_string *name;
1660        u64 total_bytes;
1661        int seeding_dev = 0;
1662        int ret = 0;
1663
1664        if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
1665                return -EROFS;
1666
1667        bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
1668                                  root->fs_info->bdev_holder);
1669        if (IS_ERR(bdev))
1670                return PTR_ERR(bdev);
1671
1672        if (root->fs_info->fs_devices->seeding) {
1673                seeding_dev = 1;
1674                down_write(&sb->s_umount);
1675                mutex_lock(&uuid_mutex);
1676        }
1677
1678        filemap_write_and_wait(bdev->bd_inode->i_mapping);
1679
1680        devices = &root->fs_info->fs_devices->devices;
1681        /*
1682         * we have the volume lock, so we don't need the extra
1683         * device list mutex while reading the list here.
1684         */
1685        list_for_each_entry(device, devices, dev_list) {
1686                if (device->bdev == bdev) {
1687                        ret = -EEXIST;
1688                        goto error;
1689                }
1690        }
1691
1692        device = kzalloc(sizeof(*device), GFP_NOFS);
1693        if (!device) {
1694                /* we can safely leave the fs_devices entry around */
1695                ret = -ENOMEM;
1696                goto error;
1697        }
1698
1699        name = rcu_string_strdup(device_path, GFP_NOFS);
1700        if (!name) {
1701                kfree(device);
1702                ret = -ENOMEM;
1703                goto error;
1704        }
1705        rcu_assign_pointer(device->name, name);
1706
1707        ret = find_next_devid(root, &device->devid);
1708        if (ret) {
1709                rcu_string_free(device->name);
1710                kfree(device);
1711                goto error;
1712        }
1713
1714        trans = btrfs_start_transaction(root, 0);
1715        if (IS_ERR(trans)) {
1716                rcu_string_free(device->name);
1717                kfree(device);
1718                ret = PTR_ERR(trans);
1719                goto error;
1720        }
1721
1722        lock_chunks(root);
1723
1724        q = bdev_get_queue(bdev);
1725        if (blk_queue_discard(q))
1726                device->can_discard = 1;
1727        device->writeable = 1;
1728        device->work.func = pending_bios_fn;
1729        generate_random_uuid(device->uuid);
1730        spin_lock_init(&device->io_lock);
1731        device->generation = trans->transid;
1732        device->io_width = root->sectorsize;
1733        device->io_align = root->sectorsize;
1734        device->sector_size = root->sectorsize;
1735        device->total_bytes = i_size_read(bdev->bd_inode);
1736        device->disk_total_bytes = device->total_bytes;
1737        device->dev_root = root->fs_info->dev_root;
1738        device->bdev = bdev;
1739        device->in_fs_metadata = 1;
1740        device->mode = FMODE_EXCL;
1741        set_blocksize(device->bdev, 4096);
1742
1743        if (seeding_dev) {
1744                sb->s_flags &= ~MS_RDONLY;
1745                ret = btrfs_prepare_sprout(root);
1746                BUG_ON(ret); /* -ENOMEM */
1747        }
1748
1749        device->fs_devices = root->fs_info->fs_devices;
1750
1751        mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1752        list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
1753        list_add(&device->dev_alloc_list,
1754                 &root->fs_info->fs_devices->alloc_list);
1755        root->fs_info->fs_devices->num_devices++;
1756        root->fs_info->fs_devices->open_devices++;
1757        root->fs_info->fs_devices->rw_devices++;
1758        root->fs_info->fs_devices->total_devices++;
1759        if (device->can_discard)
1760                root->fs_info->fs_devices->num_can_discard++;
1761        root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
1762
1763        spin_lock(&root->fs_info->free_chunk_lock);
1764        root->fs_info->free_chunk_space += device->total_bytes;
1765        spin_unlock(&root->fs_info->free_chunk_lock);
1766
1767        if (!blk_queue_nonrot(bdev_get_queue(bdev)))
1768                root->fs_info->fs_devices->rotating = 1;
1769
1770        total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
1771        btrfs_set_super_total_bytes(root->fs_info->super_copy,
1772                                    total_bytes + device->total_bytes);
1773
1774        total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
1775        btrfs_set_super_num_devices(root->fs_info->super_copy,
1776                                    total_bytes + 1);
1777        mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1778
1779        if (seeding_dev) {
1780                ret = init_first_rw_device(trans, root, device);
1781                if (ret) {
1782                        btrfs_abort_transaction(trans, root, ret);
1783                        goto error_trans;
1784                }
1785                ret = btrfs_finish_sprout(trans, root);
1786                if (ret) {
1787                        btrfs_abort_transaction(trans, root, ret);
1788                        goto error_trans;
1789                }
1790        } else {
1791                ret = btrfs_add_device(trans, root, device);
1792                if (ret) {
1793                        btrfs_abort_transaction(trans, root, ret);
1794                        goto error_trans;
1795                }
1796        }
1797
1798        /*
1799         * we've got more storage, clear any full flags on the space
1800         * infos
1801         */
1802        btrfs_clear_space_info_full(root->fs_info);
1803
1804        unlock_chunks(root);
1805        root->fs_info->num_tolerated_disk_barrier_failures =
1806                btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1807        ret = btrfs_commit_transaction(trans, root);
1808
1809        if (seeding_dev) {
1810                mutex_unlock(&uuid_mutex);
1811                up_write(&sb->s_umount);
1812
1813                if (ret) /* transaction commit */
1814                        return ret;
1815
1816                ret = btrfs_relocate_sys_chunks(root);
1817                if (ret < 0)
1818                        btrfs_error(root->fs_info, ret,
1819                                    "Failed to relocate sys chunks after "
1820                                    "device initialization. This can be fixed "
1821                                    "using the \"btrfs balance\" command.");
1822                trans = btrfs_attach_transaction(root);
1823                if (IS_ERR(trans)) {
1824                        if (PTR_ERR(trans) == -ENOENT)
1825                                return 0;
1826                        return PTR_ERR(trans);
1827                }
1828                ret = btrfs_commit_transaction(trans, root);
1829        }
1830
1831        return ret;
1832
1833error_trans:
1834        unlock_chunks(root);
1835        btrfs_end_transaction(trans, root);
1836        rcu_string_free(device->name);
1837        kfree(device);
1838error:
1839        blkdev_put(bdev, FMODE_EXCL);
1840        if (seeding_dev) {
1841                mutex_unlock(&uuid_mutex);
1842                up_write(&sb->s_umount);
1843        }
1844        return ret;
1845}
1846
1847static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
1848                                        struct btrfs_device *device)
1849{
1850        int ret;
1851        struct btrfs_path *path;
1852        struct btrfs_root *root;
1853        struct btrfs_dev_item *dev_item;
1854        struct extent_buffer *leaf;
1855        struct btrfs_key key;
1856
1857        root = device->dev_root->fs_info->chunk_root;
1858
1859        path = btrfs_alloc_path();
1860        if (!path)
1861                return -ENOMEM;
1862
1863        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1864        key.type = BTRFS_DEV_ITEM_KEY;
1865        key.offset = device->devid;
1866
1867        ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1868        if (ret < 0)
1869                goto out;
1870
1871        if (ret > 0) {
1872                ret = -ENOENT;
1873                goto out;
1874        }
1875
1876        leaf = path->nodes[0];
1877        dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1878
1879        btrfs_set_device_id(leaf, dev_item, device->devid);
1880        btrfs_set_device_type(leaf, dev_item, device->type);
1881        btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1882        btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1883        btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1884        btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
1885        btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1886        btrfs_mark_buffer_dirty(leaf);
1887
1888out:
1889        btrfs_free_path(path);
1890        return ret;
1891}
1892
1893static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
1894                      struct btrfs_device *device, u64 new_size)
1895{
1896        struct btrfs_super_block *super_copy =
1897                device->dev_root->fs_info->super_copy;
1898        u64 old_total = btrfs_super_total_bytes(super_copy);
1899        u64 diff = new_size - device->total_bytes;
1900
1901        if (!device->writeable)
1902                return -EACCES;
1903        if (new_size <= device->total_bytes)
1904                return -EINVAL;
1905
1906        btrfs_set_super_total_bytes(super_copy, old_total + diff);
1907        device->fs_devices->total_rw_bytes += diff;
1908
1909        device->total_bytes = new_size;
1910        device->disk_total_bytes = new_size;
1911        btrfs_clear_space_info_full(device->dev_root->fs_info);
1912
1913        return btrfs_update_device(trans, device);
1914}
1915
1916int btrfs_grow_device(struct btrfs_trans_handle *trans,
1917                      struct btrfs_device *device, u64 new_size)
1918{
1919        int ret;
1920        lock_chunks(device->dev_root);
1921        ret = __btrfs_grow_device(trans, device, new_size);
1922        unlock_chunks(device->dev_root);
1923        return ret;
1924}
1925
1926static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1927                            struct btrfs_root *root,
1928                            u64 chunk_tree, u64 chunk_objectid,
1929                            u64 chunk_offset)
1930{
1931        int ret;
1932        struct btrfs_path *path;
1933        struct btrfs_key key;
1934
1935        root = root->fs_info->chunk_root;
1936        path = btrfs_alloc_path();
1937        if (!path)
1938                return -ENOMEM;
1939
1940        key.objectid = chunk_objectid;
1941        key.offset = chunk_offset;
1942        key.type = BTRFS_CHUNK_ITEM_KEY;
1943
1944        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1945        if (ret < 0)
1946                goto out;
1947        else if (ret > 0) { /* Logic error or corruption */
1948                btrfs_error(root->fs_info, -ENOENT,
1949                            "Failed lookup while freeing chunk.");
1950                ret = -ENOENT;
1951                goto out;
1952        }
1953
1954        ret = btrfs_del_item(trans, root, path);
1955        if (ret < 0)
1956                btrfs_error(root->fs_info, ret,
1957                            "Failed to delete chunk item.");
1958out:
1959        btrfs_free_path(path);
1960        return ret;
1961}
1962
1963static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1964                        chunk_offset)
1965{
1966        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
1967        struct btrfs_disk_key *disk_key;
1968        struct btrfs_chunk *chunk;
1969        u8 *ptr;
1970        int ret = 0;
1971        u32 num_stripes;
1972        u32 array_size;
1973        u32 len = 0;
1974        u32 cur;
1975        struct btrfs_key key;
1976
1977        array_size = btrfs_super_sys_array_size(super_copy);
1978
1979        ptr = super_copy->sys_chunk_array;
1980        cur = 0;
1981
1982        while (cur < array_size) {
1983                disk_key = (struct btrfs_disk_key *)ptr;
1984                btrfs_disk_key_to_cpu(&key, disk_key);
1985
1986                len = sizeof(*disk_key);
1987
1988                if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1989                        chunk = (struct btrfs_chunk *)(ptr + len);
1990                        num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1991                        len += btrfs_chunk_item_size(num_stripes);
1992                } else {
1993                        ret = -EIO;
1994                        break;
1995                }
1996                if (key.objectid == chunk_objectid &&
1997                    key.offset == chunk_offset) {
1998                        memmove(ptr, ptr + len, array_size - (cur + len));
1999                        array_size -= len;
2000                        btrfs_set_super_sys_array_size(super_copy, array_size);
2001                } else {
2002                        ptr += len;
2003                        cur += len;
2004                }
2005        }
2006        return ret;
2007}
2008
2009static int btrfs_relocate_chunk(struct btrfs_root *root,
2010                         u64 chunk_tree, u64 chunk_objectid,
2011                         u64 chunk_offset)
2012{
2013        struct extent_map_tree *em_tree;
2014        struct btrfs_root *extent_root;
2015        struct btrfs_trans_handle *trans;
2016        struct extent_map *em;
2017        struct map_lookup *map;
2018        int ret;
2019        int i;
2020
2021        root = root->fs_info->chunk_root;
2022        extent_root = root->fs_info->extent_root;
2023        em_tree = &root->fs_info->mapping_tree.map_tree;
2024
2025        ret = btrfs_can_relocate(extent_root, chunk_offset);
2026        if (ret)
2027                return -ENOSPC;
2028
2029        /* step one, relocate all the extents inside this chunk */
2030        ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2031        if (ret)
2032                return ret;
2033
2034        trans = btrfs_start_transaction(root, 0);
2035        BUG_ON(IS_ERR(trans));
2036
2037        lock_chunks(root);
2038
2039        /*
2040         * step two, delete the device extents and the
2041         * chunk tree entries
2042         */
2043        read_lock(&em_tree->lock);
2044        em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2045        read_unlock(&em_tree->lock);
2046
2047        BUG_ON(!em || em->start > chunk_offset ||
2048               em->start + em->len < chunk_offset);
2049        map = (struct map_lookup *)em->bdev;
2050
2051        for (i = 0; i < map->num_stripes; i++) {
2052                ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
2053                                            map->stripes[i].physical);
2054                BUG_ON(ret);
2055
2056                if (map->stripes[i].dev) {
2057                        ret = btrfs_update_device(trans, map->stripes[i].dev);
2058                        BUG_ON(ret);
2059                }
2060        }
2061        ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
2062                               chunk_offset);
2063
2064        BUG_ON(ret);
2065
2066        trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2067
2068        if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2069                ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2070                BUG_ON(ret);
2071        }
2072
2073        ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
2074        BUG_ON(ret);
2075
2076        write_lock(&em_tree->lock);
2077        remove_extent_mapping(em_tree, em);
2078        write_unlock(&em_tree->lock);
2079
2080        kfree(map);
2081        em->bdev = NULL;
2082
2083        /* once for the tree */
2084        free_extent_map(em);
2085        /* once for us */
2086        free_extent_map(em);
2087
2088        unlock_chunks(root);
2089        btrfs_end_transaction(trans, root);
2090        return 0;
2091}
2092
2093static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2094{
2095        struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2096        struct btrfs_path *path;
2097        struct extent_buffer *leaf;
2098        struct btrfs_chunk *chunk;
2099        struct btrfs_key key;
2100        struct btrfs_key found_key;
2101        u64 chunk_tree = chunk_root->root_key.objectid;
2102        u64 chunk_type;
2103        bool retried = false;
2104        int failed = 0;
2105        int ret;
2106
2107        path = btrfs_alloc_path();
2108        if (!path)
2109                return -ENOMEM;
2110
2111again:
2112        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2113        key.offset = (u64)-1;
2114        key.type = BTRFS_CHUNK_ITEM_KEY;
2115
2116        while (1) {
2117                ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2118                if (ret < 0)
2119                        goto error;
2120                BUG_ON(ret == 0); /* Corruption */
2121
2122                ret = btrfs_previous_item(chunk_root, path, key.objectid,
2123                                          key.type);
2124                if (ret < 0)
2125                        goto error;
2126                if (ret > 0)
2127                        break;
2128
2129                leaf = path->nodes[0];
2130                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2131
2132                chunk = btrfs_item_ptr(leaf, path->slots[0],
2133                                       struct btrfs_chunk);
2134                chunk_type = btrfs_chunk_type(leaf, chunk);
2135                btrfs_release_path(path);
2136
2137                if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2138                        ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
2139                                                   found_key.objectid,
2140                                                   found_key.offset);
2141                        if (ret == -ENOSPC)
2142                                failed++;
2143                        else if (ret)
2144                                BUG();
2145                }
2146
2147                if (found_key.offset == 0)
2148                        break;
2149                key.offset = found_key.offset - 1;
2150        }
2151        ret = 0;
2152        if (failed && !retried) {
2153                failed = 0;
2154                retried = true;
2155                goto again;
2156        } else if (failed && retried) {
2157                WARN_ON(1);
2158                ret = -ENOSPC;
2159        }
2160error:
2161        btrfs_free_path(path);
2162        return ret;
2163}
2164
2165static int insert_balance_item(struct btrfs_root *root,
2166                               struct btrfs_balance_control *bctl)
2167{
2168        struct btrfs_trans_handle *trans;
2169        struct btrfs_balance_item *item;
2170        struct btrfs_disk_balance_args disk_bargs;
2171        struct btrfs_path *path;
2172        struct extent_buffer *leaf;
2173        struct btrfs_key key;
2174        int ret, err;
2175
2176        path = btrfs_alloc_path();
2177        if (!path)
2178                return -ENOMEM;
2179
2180        trans = btrfs_start_transaction(root, 0);
2181        if (IS_ERR(trans)) {
2182                btrfs_free_path(path);
2183                return PTR_ERR(trans);
2184        }
2185
2186        key.objectid = BTRFS_BALANCE_OBJECTID;
2187        key.type = BTRFS_BALANCE_ITEM_KEY;
2188        key.offset = 0;
2189
2190        ret = btrfs_insert_empty_item(trans, root, path, &key,
2191                                      sizeof(*item));
2192        if (ret)
2193                goto out;
2194
2195        leaf = path->nodes[0];
2196        item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2197
2198        memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2199
2200        btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2201        btrfs_set_balance_data(leaf, item, &disk_bargs);
2202        btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2203        btrfs_set_balance_meta(leaf, item, &disk_bargs);
2204        btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2205        btrfs_set_balance_sys(leaf, item, &disk_bargs);
2206
2207        btrfs_set_balance_flags(leaf, item, bctl->flags);
2208
2209        btrfs_mark_buffer_dirty(leaf);
2210out:
2211        btrfs_free_path(path);
2212        err = btrfs_commit_transaction(trans, root);
2213        if (err && !ret)
2214                ret = err;
2215        return ret;
2216}
2217
2218static int del_balance_item(struct btrfs_root *root)
2219{
2220        struct btrfs_trans_handle *trans;
2221        struct btrfs_path *path;
2222        struct btrfs_key key;
2223        int ret, err;
2224
2225        path = btrfs_alloc_path();
2226        if (!path)
2227                return -ENOMEM;
2228
2229        trans = btrfs_start_transaction(root, 0);
2230        if (IS_ERR(trans)) {
2231                btrfs_free_path(path);
2232                return PTR_ERR(trans);
2233        }
2234
2235        key.objectid = BTRFS_BALANCE_OBJECTID;
2236        key.type = BTRFS_BALANCE_ITEM_KEY;
2237        key.offset = 0;
2238
2239        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2240        if (ret < 0)
2241                goto out;
2242        if (ret > 0) {
2243                ret = -ENOENT;
2244                goto out;
2245        }
2246
2247        ret = btrfs_del_item(trans, root, path);
2248out:
2249        btrfs_free_path(path);
2250        err = btrfs_commit_transaction(trans, root);
2251        if (err && !ret)
2252                ret = err;
2253        return ret;
2254}
2255
2256/*
2257 * This is a heuristic used to reduce the number of chunks balanced on
2258 * resume after balance was interrupted.
2259 */
2260static void update_balance_args(struct btrfs_balance_control *bctl)
2261{
2262        /*
2263         * Turn on soft mode for chunk types that were being converted.
2264         */
2265        if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
2266                bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
2267        if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
2268                bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
2269        if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
2270                bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
2271
2272        /*
2273         * Turn on usage filter if is not already used.  The idea is
2274         * that chunks that we have already balanced should be
2275         * reasonably full.  Don't do it for chunks that are being
2276         * converted - that will keep us from relocating unconverted
2277         * (albeit full) chunks.
2278         */
2279        if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2280            !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2281                bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
2282                bctl->data.usage = 90;
2283        }
2284        if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2285            !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2286                bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
2287                bctl->sys.usage = 90;
2288        }
2289        if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
2290            !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
2291                bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
2292                bctl->meta.usage = 90;
2293        }
2294}
2295
2296/*
2297 * Should be called with both balance and volume mutexes held to
2298 * serialize other volume operations (add_dev/rm_dev/resize) with
2299 * restriper.  Same goes for unset_balance_control.
2300 */
2301static void set_balance_control(struct btrfs_balance_control *bctl)
2302{
2303        struct btrfs_fs_info *fs_info = bctl->fs_info;
2304
2305        BUG_ON(fs_info->balance_ctl);
2306
2307        spin_lock(&fs_info->balance_lock);
2308        fs_info->balance_ctl = bctl;
2309        spin_unlock(&fs_info->balance_lock);
2310}
2311
2312static void unset_balance_control(struct btrfs_fs_info *fs_info)
2313{
2314        struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2315
2316        BUG_ON(!fs_info->balance_ctl);
2317
2318        spin_lock(&fs_info->balance_lock);
2319        fs_info->balance_ctl = NULL;
2320        spin_unlock(&fs_info->balance_lock);
2321
2322        kfree(bctl);
2323}
2324
2325/*
2326 * Balance filters.  Return 1 if chunk should be filtered out
2327 * (should not be balanced).
2328 */
2329static int chunk_profiles_filter(u64 chunk_type,
2330                                 struct btrfs_balance_args *bargs)
2331{
2332        chunk_type = chunk_to_extended(chunk_type) &
2333                                BTRFS_EXTENDED_PROFILE_MASK;
2334
2335        if (bargs->profiles & chunk_type)
2336                return 0;
2337
2338        return 1;
2339}
2340
2341static u64 div_factor_fine(u64 num, int factor)
2342{
2343        if (factor <= 0)
2344                return 0;
2345        if (factor >= 100)
2346                return num;
2347
2348        num *= factor;
2349        do_div(num, 100);
2350        return num;
2351}
2352
2353static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
2354                              struct btrfs_balance_args *bargs)
2355{
2356        struct btrfs_block_group_cache *cache;
2357        u64 chunk_used, user_thresh;
2358        int ret = 1;
2359
2360        cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2361        chunk_used = btrfs_block_group_used(&cache->item);
2362
2363        user_thresh = div_factor_fine(cache->key.offset, bargs->usage);
2364        if (chunk_used < user_thresh)
2365                ret = 0;
2366
2367        btrfs_put_block_group(cache);
2368        return ret;
2369}
2370
2371static int chunk_devid_filter(struct extent_buffer *leaf,
2372                              struct btrfs_chunk *chunk,
2373                              struct btrfs_balance_args *bargs)
2374{
2375        struct btrfs_stripe *stripe;
2376        int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2377        int i;
2378
2379        for (i = 0; i < num_stripes; i++) {
2380                stripe = btrfs_stripe_nr(chunk, i);
2381                if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
2382                        return 0;
2383        }
2384
2385        return 1;
2386}
2387
2388/* [pstart, pend) */
2389static int chunk_drange_filter(struct extent_buffer *leaf,
2390                               struct btrfs_chunk *chunk,
2391                               u64 chunk_offset,
2392                               struct btrfs_balance_args *bargs)
2393{
2394        struct btrfs_stripe *stripe;
2395        int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2396        u64 stripe_offset;
2397        u64 stripe_length;
2398        int factor;
2399        int i;
2400
2401        if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
2402                return 0;
2403
2404        if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
2405             BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10))
2406                factor = 2;
2407        else
2408                factor = 1;
2409        factor = num_stripes / factor;
2410
2411        for (i = 0; i < num_stripes; i++) {
2412                stripe = btrfs_stripe_nr(chunk, i);
2413                if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
2414                        continue;
2415
2416                stripe_offset = btrfs_stripe_offset(leaf, stripe);
2417                stripe_length = btrfs_chunk_length(leaf, chunk);
2418                do_div(stripe_length, factor);
2419
2420                if (stripe_offset < bargs->pend &&
2421                    stripe_offset + stripe_length > bargs->pstart)
2422                        return 0;
2423        }
2424
2425        return 1;
2426}
2427
2428/* [vstart, vend) */
2429static int chunk_vrange_filter(struct extent_buffer *leaf,
2430                               struct btrfs_chunk *chunk,
2431                               u64 chunk_offset,
2432                               struct btrfs_balance_args *bargs)
2433{
2434        if (chunk_offset < bargs->vend &&
2435            chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
2436                /* at least part of the chunk is inside this vrange */
2437                return 0;
2438
2439        return 1;
2440}
2441
2442static int chunk_soft_convert_filter(u64 chunk_type,
2443                                     struct btrfs_balance_args *bargs)
2444{
2445        if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
2446                return 0;
2447
2448        chunk_type = chunk_to_extended(chunk_type) &
2449                                BTRFS_EXTENDED_PROFILE_MASK;
2450
2451        if (bargs->target == chunk_type)
2452                return 1;
2453
2454        return 0;
2455}
2456
2457static int should_balance_chunk(struct btrfs_root *root,
2458                                struct extent_buffer *leaf,
2459                                struct btrfs_chunk *chunk, u64 chunk_offset)
2460{
2461        struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
2462        struct btrfs_balance_args *bargs = NULL;
2463        u64 chunk_type = btrfs_chunk_type(leaf, chunk);
2464
2465        /* type filter */
2466        if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
2467              (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
2468                return 0;
2469        }
2470
2471        if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
2472                bargs = &bctl->data;
2473        else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
2474                bargs = &bctl->sys;
2475        else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
2476                bargs = &bctl->meta;
2477
2478        /* profiles filter */
2479        if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
2480            chunk_profiles_filter(chunk_type, bargs)) {
2481                return 0;
2482        }
2483
2484        /* usage filter */
2485        if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
2486            chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
2487                return 0;
2488        }
2489
2490        /* devid filter */
2491        if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
2492            chunk_devid_filter(leaf, chunk, bargs)) {
2493                return 0;
2494        }
2495
2496        /* drange filter, makes sense only with devid filter */
2497        if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
2498            chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
2499                return 0;
2500        }
2501
2502        /* vrange filter */
2503        if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
2504            chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
2505                return 0;
2506        }
2507
2508        /* soft profile changing mode */
2509        if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
2510            chunk_soft_convert_filter(chunk_type, bargs)) {
2511                return 0;
2512        }
2513
2514        return 1;
2515}
2516
2517static u64 div_factor(u64 num, int factor)
2518{
2519        if (factor == 10)
2520                return num;
2521        num *= factor;
2522        do_div(num, 10);
2523        return num;
2524}
2525
2526static int __btrfs_balance(struct btrfs_fs_info *fs_info)
2527{
2528        struct btrfs_balance_control *bctl = fs_info->balance_ctl;
2529        struct btrfs_root *chunk_root = fs_info->chunk_root;
2530        struct btrfs_root *dev_root = fs_info->dev_root;
2531        struct list_head *devices;
2532        struct btrfs_device *device;
2533        u64 old_size;
2534        u64 size_to_free;
2535        struct btrfs_chunk *chunk;
2536        struct btrfs_path *path;
2537        struct btrfs_key key;
2538        struct btrfs_key found_key;
2539        struct btrfs_trans_handle *trans;
2540        struct extent_buffer *leaf;
2541        int slot;
2542        int ret;
2543        int enospc_errors = 0;
2544        bool counting = true;
2545
2546        /* step one make some room on all the devices */
2547        devices = &fs_info->fs_devices->devices;
2548        list_for_each_entry(device, devices, dev_list) {
2549                old_size = device->total_bytes;
2550                size_to_free = div_factor(old_size, 1);
2551                size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
2552                if (!device->writeable ||
2553                    device->total_bytes - device->bytes_used > size_to_free)
2554                        continue;
2555
2556                ret = btrfs_shrink_device(device, old_size - size_to_free);
2557                if (ret == -ENOSPC)
2558                        break;
2559                BUG_ON(ret);
2560
2561                trans = btrfs_start_transaction(dev_root, 0);
2562                BUG_ON(IS_ERR(trans));
2563
2564                ret = btrfs_grow_device(trans, device, old_size);
2565                BUG_ON(ret);
2566
2567                btrfs_end_transaction(trans, dev_root);
2568        }
2569
2570        /* step two, relocate all the chunks */
2571        path = btrfs_alloc_path();
2572        if (!path) {
2573                ret = -ENOMEM;
2574                goto error;
2575        }
2576
2577        /* zero out stat counters */
2578        spin_lock(&fs_info->balance_lock);
2579        memset(&bctl->stat, 0, sizeof(bctl->stat));
2580        spin_unlock(&fs_info->balance_lock);
2581again:
2582        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2583        key.offset = (u64)-1;
2584        key.type = BTRFS_CHUNK_ITEM_KEY;
2585
2586        while (1) {
2587                if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
2588                    atomic_read(&fs_info->balance_cancel_req)) {
2589                        ret = -ECANCELED;
2590                        goto error;
2591                }
2592
2593                ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2594                if (ret < 0)
2595                        goto error;
2596
2597                /*
2598                 * this shouldn't happen, it means the last relocate
2599                 * failed
2600                 */
2601                if (ret == 0)
2602                        BUG(); /* FIXME break ? */
2603
2604                ret = btrfs_previous_item(chunk_root, path, 0,
2605                                          BTRFS_CHUNK_ITEM_KEY);
2606                if (ret) {
2607                        ret = 0;
2608                        break;
2609                }
2610
2611                leaf = path->nodes[0];
2612                slot = path->slots[0];
2613                btrfs_item_key_to_cpu(leaf, &found_key, slot);
2614
2615                if (found_key.objectid != key.objectid)
2616                        break;
2617
2618                /* chunk zero is special */
2619                if (found_key.offset == 0)
2620                        break;
2621
2622                chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2623
2624                if (!counting) {
2625                        spin_lock(&fs_info->balance_lock);
2626                        bctl->stat.considered++;
2627                        spin_unlock(&fs_info->balance_lock);
2628                }
2629
2630                ret = should_balance_chunk(chunk_root, leaf, chunk,
2631                                           found_key.offset);
2632                btrfs_release_path(path);
2633                if (!ret)
2634                        goto loop;
2635
2636                if (counting) {
2637                        spin_lock(&fs_info->balance_lock);
2638                        bctl->stat.expected++;
2639                        spin_unlock(&fs_info->balance_lock);
2640                        goto loop;
2641                }
2642
2643                ret = btrfs_relocate_chunk(chunk_root,
2644                                           chunk_root->root_key.objectid,
2645                                           found_key.objectid,
2646                                           found_key.offset);
2647                if (ret && ret != -ENOSPC)
2648                        goto error;
2649                if (ret == -ENOSPC) {
2650                        enospc_errors++;
2651                } else {
2652                        spin_lock(&fs_info->balance_lock);
2653                        bctl->stat.completed++;
2654                        spin_unlock(&fs_info->balance_lock);
2655                }
2656loop:
2657                key.offset = found_key.offset - 1;
2658        }
2659
2660        if (counting) {
2661                btrfs_release_path(path);
2662                counting = false;
2663                goto again;
2664        }
2665error:
2666        btrfs_free_path(path);
2667        if (enospc_errors) {
2668                printk(KERN_INFO "btrfs: %d enospc errors during balance\n",
2669                       enospc_errors);
2670                if (!ret)
2671                        ret = -ENOSPC;
2672        }
2673
2674        return ret;
2675}
2676
2677/**
2678 * alloc_profile_is_valid - see if a given profile is valid and reduced
2679 * @flags: profile to validate
2680 * @extended: if true @flags is treated as an extended profile
2681 */
2682static int alloc_profile_is_valid(u64 flags, int extended)
2683{
2684        u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
2685                               BTRFS_BLOCK_GROUP_PROFILE_MASK);
2686
2687        flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
2688
2689        /* 1) check that all other bits are zeroed */
2690        if (flags & ~mask)
2691                return 0;
2692
2693        /* 2) see if profile is reduced */
2694        if (flags == 0)
2695                return !extended; /* "0" is valid for usual profiles */
2696
2697        /* true if exactly one bit set */
2698        return (flags & (flags - 1)) == 0;
2699}
2700
2701static inline int balance_need_close(struct btrfs_fs_info *fs_info)
2702{
2703        /* cancel requested || normal exit path */
2704        return atomic_read(&fs_info->balance_cancel_req) ||
2705                (atomic_read(&fs_info->balance_pause_req) == 0 &&
2706                 atomic_read(&fs_info->balance_cancel_req) == 0);
2707}
2708
2709static void __cancel_balance(struct btrfs_fs_info *fs_info)
2710{
2711        int ret;
2712
2713        unset_balance_control(fs_info);
2714        ret = del_balance_item(fs_info->tree_root);
2715        BUG_ON(ret);
2716}
2717
2718void update_ioctl_balance_args(struct btrfs_fs_info *fs_info, int lock,
2719                               struct btrfs_ioctl_balance_args *bargs);
2720
2721/*
2722 * Should be called with both balance and volume mutexes held
2723 */
2724int btrfs_balance(struct btrfs_balance_control *bctl,
2725                  struct btrfs_ioctl_balance_args *bargs)
2726{
2727        struct btrfs_fs_info *fs_info = bctl->fs_info;
2728        u64 allowed;
2729        int mixed = 0;
2730        int ret;
2731
2732        if (btrfs_fs_closing(fs_info) ||
2733            atomic_read(&fs_info->balance_pause_req) ||
2734            atomic_read(&fs_info->balance_cancel_req)) {
2735                ret = -EINVAL;
2736                goto out;
2737        }
2738
2739        allowed = btrfs_super_incompat_flags(fs_info->super_copy);
2740        if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
2741                mixed = 1;
2742
2743        /*
2744         * In case of mixed groups both data and meta should be picked,
2745         * and identical options should be given for both of them.
2746         */
2747        allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
2748        if (mixed && (bctl->flags & allowed)) {
2749                if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
2750                    !(bctl->flags & BTRFS_BALANCE_METADATA) ||
2751                    memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
2752                        printk(KERN_ERR "btrfs: with mixed groups data and "
2753                               "metadata balance options must be the same\n");
2754                        ret = -EINVAL;
2755                        goto out;
2756                }
2757        }
2758
2759        allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
2760        if (fs_info->fs_devices->num_devices == 1)
2761                allowed |= BTRFS_BLOCK_GROUP_DUP;
2762        else if (fs_info->fs_devices->num_devices < 4)
2763                allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
2764        else
2765                allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
2766                                BTRFS_BLOCK_GROUP_RAID10);
2767
2768        if ((bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2769            (!alloc_profile_is_valid(bctl->data.target, 1) ||
2770             (bctl->data.target & ~allowed))) {
2771                printk(KERN_ERR "btrfs: unable to start balance with target "
2772                       "data profile %llu\n",
2773                       (unsigned long long)bctl->data.target);
2774                ret = -EINVAL;
2775                goto out;
2776        }
2777        if ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2778            (!alloc_profile_is_valid(bctl->meta.target, 1) ||
2779             (bctl->meta.target & ~allowed))) {
2780                printk(KERN_ERR "btrfs: unable to start balance with target "
2781                       "metadata profile %llu\n",
2782                       (unsigned long long)bctl->meta.target);
2783                ret = -EINVAL;
2784                goto out;
2785        }
2786        if ((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2787            (!alloc_profile_is_valid(bctl->sys.target, 1) ||
2788             (bctl->sys.target & ~allowed))) {
2789                printk(KERN_ERR "btrfs: unable to start balance with target "
2790                       "system profile %llu\n",
2791                       (unsigned long long)bctl->sys.target);
2792                ret = -EINVAL;
2793                goto out;
2794        }
2795
2796        /* allow dup'ed data chunks only in mixed mode */
2797        if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2798            (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
2799                printk(KERN_ERR "btrfs: dup for data is not allowed\n");
2800                ret = -EINVAL;
2801                goto out;
2802        }
2803
2804        /* allow to reduce meta or sys integrity only if force set */
2805        allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2806                        BTRFS_BLOCK_GROUP_RAID10;
2807        if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2808             (fs_info->avail_system_alloc_bits & allowed) &&
2809             !(bctl->sys.target & allowed)) ||
2810            ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
2811             (fs_info->avail_metadata_alloc_bits & allowed) &&
2812             !(bctl->meta.target & allowed))) {
2813                if (bctl->flags & BTRFS_BALANCE_FORCE) {
2814                        printk(KERN_INFO "btrfs: force reducing metadata "
2815                               "integrity\n");
2816                } else {
2817                        printk(KERN_ERR "btrfs: balance will reduce metadata "
2818                               "integrity, use force if you want this\n");
2819                        ret = -EINVAL;
2820                        goto out;
2821                }
2822        }
2823
2824        if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
2825                int num_tolerated_disk_barrier_failures;
2826                u64 target = bctl->sys.target;
2827
2828                num_tolerated_disk_barrier_failures =
2829                        btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2830                if (num_tolerated_disk_barrier_failures > 0 &&
2831                    (target &
2832                     (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
2833                      BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
2834                        num_tolerated_disk_barrier_failures = 0;
2835                else if (num_tolerated_disk_barrier_failures > 1 &&
2836                         (target &
2837                          (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
2838                        num_tolerated_disk_barrier_failures = 1;
2839
2840                fs_info->num_tolerated_disk_barrier_failures =
2841                        num_tolerated_disk_barrier_failures;
2842        }
2843
2844        ret = insert_balance_item(fs_info->tree_root, bctl);
2845        if (ret && ret != -EEXIST)
2846                goto out;
2847
2848        if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
2849                BUG_ON(ret == -EEXIST);
2850                set_balance_control(bctl);
2851        } else {
2852                BUG_ON(ret != -EEXIST);
2853                spin_lock(&fs_info->balance_lock);
2854                update_balance_args(bctl);
2855                spin_unlock(&fs_info->balance_lock);
2856        }
2857
2858        atomic_inc(&fs_info->balance_running);
2859        mutex_unlock(&fs_info->balance_mutex);
2860
2861        ret = __btrfs_balance(fs_info);
2862
2863        mutex_lock(&fs_info->balance_mutex);
2864        atomic_dec(&fs_info->balance_running);
2865
2866        if (bargs) {
2867                memset(bargs, 0, sizeof(*bargs));
2868                update_ioctl_balance_args(fs_info, 0, bargs);
2869        }
2870
2871        if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
2872            balance_need_close(fs_info)) {
2873                __cancel_balance(fs_info);
2874        }
2875
2876        if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
2877                fs_info->num_tolerated_disk_barrier_failures =
2878                        btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2879        }
2880
2881        wake_up(&fs_info->balance_wait_q);
2882
2883        return ret;
2884out:
2885        if (bctl->flags & BTRFS_BALANCE_RESUME)
2886                __cancel_balance(fs_info);
2887        else
2888                kfree(bctl);
2889        return ret;
2890}
2891
2892static int balance_kthread(void *data)
2893{
2894        struct btrfs_fs_info *fs_info = data;
2895        int ret = 0;
2896
2897        mutex_lock(&fs_info->volume_mutex);
2898        mutex_lock(&fs_info->balance_mutex);
2899
2900        if (fs_info->balance_ctl) {
2901                printk(KERN_INFO "btrfs: continuing balance\n");
2902                ret = btrfs_balance(fs_info->balance_ctl, NULL);
2903        }
2904
2905        mutex_unlock(&fs_info->balance_mutex);
2906        mutex_unlock(&fs_info->volume_mutex);
2907
2908        return ret;
2909}
2910
2911int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
2912{
2913        struct task_struct *tsk;
2914
2915        spin_lock(&fs_info->balance_lock);
2916        if (!fs_info->balance_ctl) {
2917                spin_unlock(&fs_info->balance_lock);
2918                return 0;
2919        }
2920        spin_unlock(&fs_info->balance_lock);
2921
2922        if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
2923                printk(KERN_INFO "btrfs: force skipping balance\n");
2924                return 0;
2925        }
2926
2927        tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
2928        if (IS_ERR(tsk))
2929                return PTR_ERR(tsk);
2930
2931        return 0;
2932}
2933
2934int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
2935{
2936        struct btrfs_balance_control *bctl;
2937        struct btrfs_balance_item *item;
2938        struct btrfs_disk_balance_args disk_bargs;
2939        struct btrfs_path *path;
2940        struct extent_buffer *leaf;
2941        struct btrfs_key key;
2942        int ret;
2943
2944        path = btrfs_alloc_path();
2945        if (!path)
2946                return -ENOMEM;
2947
2948        key.objectid = BTRFS_BALANCE_OBJECTID;
2949        key.type = BTRFS_BALANCE_ITEM_KEY;
2950        key.offset = 0;
2951
2952        ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
2953        if (ret < 0)
2954                goto out;
2955        if (ret > 0) { /* ret = -ENOENT; */
2956                ret = 0;
2957                goto out;
2958        }
2959
2960        bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
2961        if (!bctl) {
2962                ret = -ENOMEM;
2963                goto out;
2964        }
2965
2966        leaf = path->nodes[0];
2967        item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2968
2969        bctl->fs_info = fs_info;
2970        bctl->flags = btrfs_balance_flags(leaf, item);
2971        bctl->flags |= BTRFS_BALANCE_RESUME;
2972
2973        btrfs_balance_data(leaf, item, &disk_bargs);
2974        btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
2975        btrfs_balance_meta(leaf, item, &disk_bargs);
2976        btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
2977        btrfs_balance_sys(leaf, item, &disk_bargs);
2978        btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
2979
2980        mutex_lock(&fs_info->volume_mutex);
2981        mutex_lock(&fs_info->balance_mutex);
2982
2983        set_balance_control(bctl);
2984
2985        mutex_unlock(&fs_info->balance_mutex);
2986        mutex_unlock(&fs_info->volume_mutex);
2987out:
2988        btrfs_free_path(path);
2989        return ret;
2990}
2991
2992int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
2993{
2994        int ret = 0;
2995
2996        mutex_lock(&fs_info->balance_mutex);
2997        if (!fs_info->balance_ctl) {
2998                mutex_unlock(&fs_info->balance_mutex);
2999                return -ENOTCONN;
3000        }
3001
3002        if (atomic_read(&fs_info->balance_running)) {
3003                atomic_inc(&fs_info->balance_pause_req);
3004                mutex_unlock(&fs_info->balance_mutex);
3005
3006                wait_event(fs_info->balance_wait_q,
3007                           atomic_read(&fs_info->balance_running) == 0);
3008
3009                mutex_lock(&fs_info->balance_mutex);
3010                /* we are good with balance_ctl ripped off from under us */
3011                BUG_ON(atomic_read(&fs_info->balance_running));
3012                atomic_dec(&fs_info->balance_pause_req);
3013        } else {
3014                ret = -ENOTCONN;
3015        }
3016
3017        mutex_unlock(&fs_info->balance_mutex);
3018        return ret;
3019}
3020
3021int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3022{
3023        mutex_lock(&fs_info->balance_mutex);
3024        if (!fs_info->balance_ctl) {
3025                mutex_unlock(&fs_info->balance_mutex);
3026                return -ENOTCONN;
3027        }
3028
3029        atomic_inc(&fs_info->balance_cancel_req);
3030        /*
3031         * if we are running just wait and return, balance item is
3032         * deleted in btrfs_balance in this case
3033         */
3034        if (atomic_read(&fs_info->balance_running)) {
3035                mutex_unlock(&fs_info->balance_mutex);
3036                wait_event(fs_info->balance_wait_q,
3037                           atomic_read(&fs_info->balance_running) == 0);
3038                mutex_lock(&fs_info->balance_mutex);
3039        } else {
3040                /* __cancel_balance needs volume_mutex */
3041                mutex_unlock(&fs_info->balance_mutex);
3042                mutex_lock(&fs_info->volume_mutex);
3043                mutex_lock(&fs_info->balance_mutex);
3044
3045                if (fs_info->balance_ctl)
3046                        __cancel_balance(fs_info);
3047
3048                mutex_unlock(&fs_info->volume_mutex);
3049        }
3050
3051        BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3052        atomic_dec(&fs_info->balance_cancel_req);
3053        mutex_unlock(&fs_info->balance_mutex);
3054        return 0;
3055}
3056
3057/*
3058 * shrinking a device means finding all of the device extents past
3059 * the new size, and then following the back refs to the chunks.
3060 * The chunk relocation code actually frees the device extent
3061 */
3062int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
3063{
3064        struct btrfs_trans_handle *trans;
3065        struct btrfs_root *root = device->dev_root;
3066        struct btrfs_dev_extent *dev_extent = NULL;
3067        struct btrfs_path *path;
3068        u64 length;
3069        u64 chunk_tree;
3070        u64 chunk_objectid;
3071        u64 chunk_offset;
3072        int ret;
3073        int slot;
3074        int failed = 0;
3075        bool retried = false;
3076        struct extent_buffer *l;
3077        struct btrfs_key key;
3078        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3079        u64 old_total = btrfs_super_total_bytes(super_copy);
3080        u64 old_size = device->total_bytes;
3081        u64 diff = device->total_bytes - new_size;
3082
3083        if (new_size >= device->total_bytes)
3084                return -EINVAL;
3085
3086        path = btrfs_alloc_path();
3087        if (!path)
3088                return -ENOMEM;
3089
3090        path->reada = 2;
3091
3092        lock_chunks(root);
3093
3094        device->total_bytes = new_size;
3095        if (device->writeable) {
3096                device->fs_devices->total_rw_bytes -= diff;
3097                spin_lock(&root->fs_info->free_chunk_lock);
3098                root->fs_info->free_chunk_space -= diff;
3099                spin_unlock(&root->fs_info->free_chunk_lock);
3100        }
3101        unlock_chunks(root);
3102
3103again:
3104        key.objectid = device->devid;
3105        key.offset = (u64)-1;
3106        key.type = BTRFS_DEV_EXTENT_KEY;
3107
3108        do {
3109                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3110                if (ret < 0)
3111                        goto done;
3112
3113                ret = btrfs_previous_item(root, path, 0, key.type);
3114                if (ret < 0)
3115                        goto done;
3116                if (ret) {
3117                        ret = 0;
3118                        btrfs_release_path(path);
3119                        break;
3120                }
3121
3122                l = path->nodes[0];
3123                slot = path->slots[0];
3124                btrfs_item_key_to_cpu(l, &key, path->slots[0]);
3125
3126                if (key.objectid != device->devid) {
3127                        btrfs_release_path(path);
3128                        break;
3129                }
3130
3131                dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3132                length = btrfs_dev_extent_length(l, dev_extent);
3133
3134                if (key.offset + length <= new_size) {
3135                        btrfs_release_path(path);
3136                        break;
3137                }
3138
3139                chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
3140                chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
3141                chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3142                btrfs_release_path(path);
3143
3144                ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
3145                                           chunk_offset);
3146                if (ret && ret != -ENOSPC)
3147                        goto done;
3148                if (ret == -ENOSPC)
3149                        failed++;
3150        } while (key.offset-- > 0);
3151
3152        if (failed && !retried) {
3153                failed = 0;
3154                retried = true;
3155                goto again;
3156        } else if (failed && retried) {
3157                ret = -ENOSPC;
3158                lock_chunks(root);
3159
3160                device->total_bytes = old_size;
3161                if (device->writeable)
3162                        device->fs_devices->total_rw_bytes += diff;
3163                spin_lock(&root->fs_info->free_chunk_lock);
3164                root->fs_info->free_chunk_space += diff;
3165                spin_unlock(&root->fs_info->free_chunk_lock);
3166                unlock_chunks(root);
3167                goto done;
3168        }
3169
3170        /* Shrinking succeeded, else we would be at "done". */
3171        trans = btrfs_start_transaction(root, 0);
3172        if (IS_ERR(trans)) {
3173                ret = PTR_ERR(trans);
3174                goto done;
3175        }
3176
3177        lock_chunks(root);
3178
3179        device->disk_total_bytes = new_size;
3180        /* Now btrfs_update_device() will change the on-disk size. */
3181        ret = btrfs_update_device(trans, device);
3182        if (ret) {
3183                unlock_chunks(root);
3184                btrfs_end_transaction(trans, root);
3185                goto done;
3186        }
3187        WARN_ON(diff > old_total);
3188        btrfs_set_super_total_bytes(super_copy, old_total - diff);
3189        unlock_chunks(root);
3190        btrfs_end_transaction(trans, root);
3191done:
3192        btrfs_free_path(path);
3193        return ret;
3194}
3195
3196static int btrfs_add_system_chunk(struct btrfs_root *root,
3197                           struct btrfs_key *key,
3198                           struct btrfs_chunk *chunk, int item_size)
3199{
3200        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
3201        struct btrfs_disk_key disk_key;
3202        u32 array_size;
3203        u8 *ptr;
3204
3205        array_size = btrfs_super_sys_array_size(super_copy);
3206        if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
3207                return -EFBIG;
3208
3209        ptr = super_copy->sys_chunk_array + array_size;
3210        btrfs_cpu_key_to_disk(&disk_key, key);
3211        memcpy(ptr, &disk_key, sizeof(disk_key));
3212        ptr += sizeof(disk_key);
3213        memcpy(ptr, chunk, item_size);
3214        item_size += sizeof(disk_key);
3215        btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
3216        return 0;
3217}
3218
3219/*
3220 * sort the devices in descending order by max_avail, total_avail
3221 */
3222static int btrfs_cmp_device_info(const void *a, const void *b)
3223{
3224        const struct btrfs_device_info *di_a = a;
3225        const struct btrfs_device_info *di_b = b;
3226
3227        if (di_a->max_avail > di_b->max_avail)
3228                return -1;
3229        if (di_a->max_avail < di_b->max_avail)
3230                return 1;
3231        if (di_a->total_avail > di_b->total_avail)
3232                return -1;
3233        if (di_a->total_avail < di_b->total_avail)
3234                return 1;
3235        return 0;
3236}
3237
3238static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3239                               struct btrfs_root *extent_root,
3240                               struct map_lookup **map_ret,
3241                               u64 *num_bytes_out, u64 *stripe_size_out,
3242                               u64 start, u64 type)
3243{
3244        struct btrfs_fs_info *info = extent_root->fs_info;
3245        struct btrfs_fs_devices *fs_devices = info->fs_devices;
3246        struct list_head *cur;
3247        struct map_lookup *map = NULL;
3248        struct extent_map_tree *em_tree;
3249        struct extent_map *em;
3250        struct btrfs_device_info *devices_info = NULL;
3251        u64 total_avail;
3252        int num_stripes;        /* total number of stripes to allocate */
3253        int sub_stripes;        /* sub_stripes info for map */
3254        int dev_stripes;        /* stripes per dev */
3255        int devs_max;           /* max devs to use */
3256        int devs_min;           /* min devs needed */
3257        int devs_increment;     /* ndevs has to be a multiple of this */
3258        int ncopies;            /* how many copies to data has */
3259        int ret;
3260        u64 max_stripe_size;
3261        u64 max_chunk_size;
3262        u64 stripe_size;
3263        u64 num_bytes;
3264        int ndevs;
3265        int i;
3266        int j;
3267
3268        BUG_ON(!alloc_profile_is_valid(type, 0));
3269
3270        if (list_empty(&fs_devices->alloc_list))
3271                return -ENOSPC;
3272
3273        sub_stripes = 1;
3274        dev_stripes = 1;
3275        devs_increment = 1;
3276        ncopies = 1;
3277        devs_max = 0;   /* 0 == as many as possible */
3278        devs_min = 1;
3279
3280        /*
3281         * define the properties of each RAID type.
3282         * FIXME: move this to a global table and use it in all RAID
3283         * calculation code
3284         */
3285        if (type & (BTRFS_BLOCK_GROUP_DUP)) {
3286                dev_stripes = 2;
3287                ncopies = 2;
3288                devs_max = 1;
3289        } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
3290                devs_min = 2;
3291        } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
3292                devs_increment = 2;
3293                ncopies = 2;
3294                devs_max = 2;
3295                devs_min = 2;
3296        } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
3297                sub_stripes = 2;
3298                devs_increment = 2;
3299                ncopies = 2;
3300                devs_min = 4;
3301        } else {
3302                devs_max = 1;
3303        }
3304
3305        if (type & BTRFS_BLOCK_GROUP_DATA) {
3306                max_stripe_size = 1024 * 1024 * 1024;
3307                max_chunk_size = 10 * max_stripe_size;
3308        } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
3309                /* for larger filesystems, use larger metadata chunks */
3310                if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
3311                        max_stripe_size = 1024 * 1024 * 1024;
3312                else
3313                        max_stripe_size = 256 * 1024 * 1024;
3314                max_chunk_size = max_stripe_size;
3315        } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
3316                max_stripe_size = 32 * 1024 * 1024;
3317                max_chunk_size = 2 * max_stripe_size;
3318        } else {
3319                printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
3320                       type);
3321                BUG_ON(1);
3322        }
3323
3324        /* we don't want a chunk larger than 10% of writeable space */
3325        max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
3326                             max_chunk_size);
3327
3328        devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
3329                               GFP_NOFS);
3330        if (!devices_info)
3331                return -ENOMEM;
3332
3333        cur = fs_devices->alloc_list.next;
3334
3335        /*
3336         * in the first pass through the devices list, we gather information
3337         * about the available holes on each device.
3338         */
3339        ndevs = 0;
3340        while (cur != &fs_devices->alloc_list) {
3341                struct btrfs_device *device;
3342                u64 max_avail;
3343                u64 dev_offset;
3344
3345                device = list_entry(cur, struct btrfs_device, dev_alloc_list);
3346
3347                cur = cur->next;
3348
3349                if (!device->writeable) {
3350                        printk(KERN_ERR
3351                               "btrfs: read-only device in alloc_list\n");
3352                        WARN_ON(1);
3353                        continue;
3354                }
3355
3356                if (!device->in_fs_metadata)
3357                        continue;
3358
3359                if (device->total_bytes > device->bytes_used)
3360                        total_avail = device->total_bytes - device->bytes_used;
3361                else
3362                        total_avail = 0;
3363
3364                /* If there is no space on this device, skip it. */
3365                if (total_avail == 0)
3366                        continue;
3367
3368                ret = find_free_dev_extent(device,
3369                                           max_stripe_size * dev_stripes,
3370                                           &dev_offset, &max_avail);
3371                if (ret && ret != -ENOSPC)
3372                        goto error;
3373
3374                if (ret == 0)
3375                        max_avail = max_stripe_size * dev_stripes;
3376
3377                if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
3378                        continue;
3379
3380                devices_info[ndevs].dev_offset = dev_offset;
3381                devices_info[ndevs].max_avail = max_avail;
3382                devices_info[ndevs].total_avail = total_avail;
3383                devices_info[ndevs].dev = device;
3384                ++ndevs;
3385        }
3386
3387        /*
3388         * now sort the devices by hole size / available space
3389         */
3390        sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
3391             btrfs_cmp_device_info, NULL);
3392
3393        /* round down to number of usable stripes */
3394        ndevs -= ndevs % devs_increment;
3395
3396        if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
3397                ret = -ENOSPC;
3398                goto error;
3399        }
3400
3401        if (devs_max && ndevs > devs_max)
3402                ndevs = devs_max;
3403        /*
3404         * the primary goal is to maximize the number of stripes, so use as many
3405         * devices as possible, even if the stripes are not maximum sized.
3406         */
3407        stripe_size = devices_info[ndevs-1].max_avail;
3408        num_stripes = ndevs * dev_stripes;
3409
3410        if (stripe_size * ndevs > max_chunk_size * ncopies) {
3411                stripe_size = max_chunk_size * ncopies;
3412                do_div(stripe_size, ndevs);
3413        }
3414
3415        do_div(stripe_size, dev_stripes);
3416
3417        /* align to BTRFS_STRIPE_LEN */
3418        do_div(stripe_size, BTRFS_STRIPE_LEN);
3419        stripe_size *= BTRFS_STRIPE_LEN;
3420
3421        map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
3422        if (!map) {
3423                ret = -ENOMEM;
3424                goto error;
3425        }
3426        map->num_stripes = num_stripes;
3427
3428        for (i = 0; i < ndevs; ++i) {
3429                for (j = 0; j < dev_stripes; ++j) {
3430                        int s = i * dev_stripes + j;
3431                        map->stripes[s].dev = devices_info[i].dev;
3432                        map->stripes[s].physical = devices_info[i].dev_offset +
3433                                                   j * stripe_size;
3434                }
3435        }
3436        map->sector_size = extent_root->sectorsize;
3437        map->stripe_len = BTRFS_STRIPE_LEN;
3438        map->io_align = BTRFS_STRIPE_LEN;
3439        map->io_width = BTRFS_STRIPE_LEN;
3440        map->type = type;
3441        map->sub_stripes = sub_stripes;
3442
3443        *map_ret = map;
3444        num_bytes = stripe_size * (num_stripes / ncopies);
3445
3446        *stripe_size_out = stripe_size;
3447        *num_bytes_out = num_bytes;
3448
3449        trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
3450
3451        em = alloc_extent_map();
3452        if (!em) {
3453                ret = -ENOMEM;
3454                goto error;
3455        }
3456        em->bdev = (struct block_device *)map;
3457        em->start = start;
3458        em->len = num_bytes;
3459        em->block_start = 0;
3460        em->block_len = em->len;
3461
3462        em_tree = &extent_root->fs_info->mapping_tree.map_tree;
3463        write_lock(&em_tree->lock);
3464        ret = add_extent_mapping(em_tree, em);
3465        write_unlock(&em_tree->lock);
3466        free_extent_map(em);
3467        if (ret)
3468                goto error;
3469
3470        ret = btrfs_make_block_group(trans, extent_root, 0, type,
3471                                     BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3472                                     start, num_bytes);
3473        if (ret)
3474                goto error;
3475
3476        for (i = 0; i < map->num_stripes; ++i) {
3477                struct btrfs_device *device;
3478                u64 dev_offset;
3479
3480                device = map->stripes[i].dev;
3481                dev_offset = map->stripes[i].physical;
3482
3483                ret = btrfs_alloc_dev_extent(trans, device,
3484                                info->chunk_root->root_key.objectid,
3485                                BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3486                                start, dev_offset, stripe_size);
3487                if (ret) {
3488                        btrfs_abort_transaction(trans, extent_root, ret);
3489                        goto error;
3490                }
3491        }
3492
3493        kfree(devices_info);
3494        return 0;
3495
3496error:
3497        kfree(map);
3498        kfree(devices_info);
3499        return ret;
3500}
3501
3502static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
3503                                struct btrfs_root *extent_root,
3504                                struct map_lookup *map, u64 chunk_offset,
3505                                u64 chunk_size, u64 stripe_size)
3506{
3507        u64 dev_offset;
3508        struct btrfs_key key;
3509        struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3510        struct btrfs_device *device;
3511        struct btrfs_chunk *chunk;
3512        struct btrfs_stripe *stripe;
3513        size_t item_size = btrfs_chunk_item_size(map->num_stripes);
3514        int index = 0;
3515        int ret;
3516
3517        chunk = kzalloc(item_size, GFP_NOFS);
3518        if (!chunk)
3519                return -ENOMEM;
3520
3521        index = 0;
3522        while (index < map->num_stripes) {
3523                device = map->stripes[index].dev;
3524                device->bytes_used += stripe_size;
3525                ret = btrfs_update_device(trans, device);
3526                if (ret)
3527                        goto out_free;
3528                index++;
3529        }
3530
3531        spin_lock(&extent_root->fs_info->free_chunk_lock);
3532        extent_root->fs_info->free_chunk_space -= (stripe_size *
3533                                                   map->num_stripes);
3534        spin_unlock(&extent_root->fs_info->free_chunk_lock);
3535
3536        index = 0;
3537        stripe = &chunk->stripe;
3538        while (index < map->num_stripes) {
3539                device = map->stripes[index].dev;
3540                dev_offset = map->stripes[index].physical;
3541
3542                btrfs_set_stack_stripe_devid(stripe, device->devid);
3543                btrfs_set_stack_stripe_offset(stripe, dev_offset);
3544                memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
3545                stripe++;
3546                index++;
3547        }
3548
3549        btrfs_set_stack_chunk_length(chunk, chunk_size);
3550        btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
3551        btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
3552        btrfs_set_stack_chunk_type(chunk, map->type);
3553        btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
3554        btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
3555        btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
3556        btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
3557        btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
3558
3559        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3560        key.type = BTRFS_CHUNK_ITEM_KEY;
3561        key.offset = chunk_offset;
3562
3563        ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
3564
3565        if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
3566                /*
3567                 * TODO: Cleanup of inserted chunk root in case of
3568                 * failure.
3569                 */
3570                ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
3571                                             item_size);
3572        }
3573
3574out_free:
3575        kfree(chunk);
3576        return ret;
3577}
3578
3579/*
3580 * Chunk allocation falls into two parts. The first part does works
3581 * that make the new allocated chunk useable, but not do any operation
3582 * that modifies the chunk tree. The second part does the works that
3583 * require modifying the chunk tree. This division is important for the
3584 * bootstrap process of adding storage to a seed btrfs.
3585 */
3586int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
3587                      struct btrfs_root *extent_root, u64 type)
3588{
3589        u64 chunk_offset;
3590        u64 chunk_size;
3591        u64 stripe_size;
3592        struct map_lookup *map;
3593        struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
3594        int ret;
3595
3596        ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
3597                              &chunk_offset);
3598        if (ret)
3599                return ret;
3600
3601        ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3602                                  &stripe_size, chunk_offset, type);
3603        if (ret)
3604                return ret;
3605
3606        ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3607                                   chunk_size, stripe_size);
3608        if (ret)
3609                return ret;
3610        return 0;
3611}
3612
3613static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
3614                                         struct btrfs_root *root,
3615                                         struct btrfs_device *device)
3616{
3617        u64 chunk_offset;
3618        u64 sys_chunk_offset;
3619        u64 chunk_size;
3620        u64 sys_chunk_size;
3621        u64 stripe_size;
3622        u64 sys_stripe_size;
3623        u64 alloc_profile;
3624        struct map_lookup *map;
3625        struct map_lookup *sys_map;
3626        struct btrfs_fs_info *fs_info = root->fs_info;
3627        struct btrfs_root *extent_root = fs_info->extent_root;
3628        int ret;
3629
3630        ret = find_next_chunk(fs_info->chunk_root,
3631                              BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
3632        if (ret)
3633                return ret;
3634
3635        alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
3636                                fs_info->avail_metadata_alloc_bits;
3637        alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3638
3639        ret = __btrfs_alloc_chunk(trans, extent_root, &map, &chunk_size,
3640                                  &stripe_size, chunk_offset, alloc_profile);
3641        if (ret)
3642                return ret;
3643
3644        sys_chunk_offset = chunk_offset + chunk_size;
3645
3646        alloc_profile = BTRFS_BLOCK_GROUP_SYSTEM |
3647                                fs_info->avail_system_alloc_bits;
3648        alloc_profile = btrfs_reduce_alloc_profile(root, alloc_profile);
3649
3650        ret = __btrfs_alloc_chunk(trans, extent_root, &sys_map,
3651                                  &sys_chunk_size, &sys_stripe_size,
3652                                  sys_chunk_offset, alloc_profile);
3653        if (ret) {
3654                btrfs_abort_transaction(trans, root, ret);
3655                goto out;
3656        }
3657
3658        ret = btrfs_add_device(trans, fs_info->chunk_root, device);
3659        if (ret) {
3660                btrfs_abort_transaction(trans, root, ret);
3661                goto out;
3662        }
3663
3664        /*
3665         * Modifying chunk tree needs allocating new blocks from both
3666         * system block group and metadata block group. So we only can
3667         * do operations require modifying the chunk tree after both
3668         * block groups were created.
3669         */
3670        ret = __finish_chunk_alloc(trans, extent_root, map, chunk_offset,
3671                                   chunk_size, stripe_size);
3672        if (ret) {
3673                btrfs_abort_transaction(trans, root, ret);
3674                goto out;
3675        }
3676
3677        ret = __finish_chunk_alloc(trans, extent_root, sys_map,
3678                                   sys_chunk_offset, sys_chunk_size,
3679                                   sys_stripe_size);
3680        if (ret)
3681                btrfs_abort_transaction(trans, root, ret);
3682
3683out:
3684
3685        return ret;
3686}
3687
3688int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
3689{
3690        struct extent_map *em;
3691        struct map_lookup *map;
3692        struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
3693        int readonly = 0;
3694        int i;
3695
3696        read_lock(&map_tree->map_tree.lock);
3697        em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3698        read_unlock(&map_tree->map_tree.lock);
3699        if (!em)
3700                return 1;
3701
3702        if (btrfs_test_opt(root, DEGRADED)) {
3703                free_extent_map(em);
3704                return 0;
3705        }
3706
3707        map = (struct map_lookup *)em->bdev;
3708        for (i = 0; i < map->num_stripes; i++) {
3709                if (!map->stripes[i].dev->writeable) {
3710                        readonly = 1;
3711                        break;
3712                }
3713        }
3714        free_extent_map(em);
3715        return readonly;
3716}
3717
3718void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
3719{
3720        extent_map_tree_init(&tree->map_tree);
3721}
3722
3723void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
3724{
3725        struct extent_map *em;
3726
3727        while (1) {
3728                write_lock(&tree->map_tree.lock);
3729                em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
3730                if (em)
3731                        remove_extent_mapping(&tree->map_tree, em);
3732                write_unlock(&tree->map_tree.lock);
3733                if (!em)
3734                        break;
3735                kfree(em->bdev);
3736                /* once for us */
3737                free_extent_map(em);
3738                /* once for the tree */
3739                free_extent_map(em);
3740        }
3741}
3742
3743int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
3744{
3745        struct extent_map *em;
3746        struct map_lookup *map;
3747        struct extent_map_tree *em_tree = &map_tree->map_tree;
3748        int ret;
3749
3750        read_lock(&em_tree->lock);
3751        em = lookup_extent_mapping(em_tree, logical, len);
3752        read_unlock(&em_tree->lock);
3753        BUG_ON(!em);
3754
3755        BUG_ON(em->start > logical || em->start + em->len < logical);
3756        map = (struct map_lookup *)em->bdev;
3757        if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
3758                ret = map->num_stripes;
3759        else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
3760                ret = map->sub_stripes;
3761        else
3762                ret = 1;
3763        free_extent_map(em);
3764        return ret;
3765}
3766
3767static int find_live_mirror(struct map_lookup *map, int first, int num,
3768                            int optimal)
3769{
3770        int i;
3771        if (map->stripes[optimal].dev->bdev)
3772                return optimal;
3773        for (i = first; i < first + num; i++) {
3774                if (map->stripes[i].dev->bdev)
3775                        return i;
3776        }
3777        /* we couldn't find one that doesn't fail.  Just return something
3778         * and the io error handling code will clean up eventually
3779         */
3780        return optimal;
3781}
3782
3783static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
3784                             u64 logical, u64 *length,
3785                             struct btrfs_bio **bbio_ret,
3786                             int mirror_num)
3787{
3788        struct extent_map *em;
3789        struct map_lookup *map;
3790        struct extent_map_tree *em_tree = &map_tree->map_tree;
3791        u64 offset;
3792        u64 stripe_offset;
3793        u64 stripe_end_offset;
3794        u64 stripe_nr;
3795        u64 stripe_nr_orig;
3796        u64 stripe_nr_end;
3797        int stripe_index;
3798        int i;
3799        int ret = 0;
3800        int num_stripes;
3801        int max_errors = 0;
3802        struct btrfs_bio *bbio = NULL;
3803
3804        read_lock(&em_tree->lock);
3805        em = lookup_extent_mapping(em_tree, logical, *length);
3806        read_unlock(&em_tree->lock);
3807
3808        if (!em) {
3809                printk(KERN_CRIT "btrfs: unable to find logical %llu len %llu\n",
3810                       (unsigned long long)logical,
3811                       (unsigned long long)*length);
3812                BUG();
3813        }
3814
3815        BUG_ON(em->start > logical || em->start + em->len < logical);
3816        map = (struct map_lookup *)em->bdev;
3817        offset = logical - em->start;
3818
3819        if (mirror_num > map->num_stripes)
3820                mirror_num = 0;
3821
3822        stripe_nr = offset;
3823        /*
3824         * stripe_nr counts the total number of stripes we have to stride
3825         * to get to this block
3826         */
3827        do_div(stripe_nr, map->stripe_len);
3828
3829        stripe_offset = stripe_nr * map->stripe_len;
3830        BUG_ON(offset < stripe_offset);
3831
3832        /* stripe_offset is the offset of this block in its stripe*/
3833        stripe_offset = offset - stripe_offset;
3834
3835        if (rw & REQ_DISCARD)
3836                *length = min_t(u64, em->len - offset, *length);
3837        else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
3838                /* we limit the length of each bio to what fits in a stripe */
3839                *length = min_t(u64, em->len - offset,
3840                                map->stripe_len - stripe_offset);
3841        } else {
3842                *length = em->len - offset;
3843        }
3844
3845        if (!bbio_ret)
3846                goto out;
3847
3848        num_stripes = 1;
3849        stripe_index = 0;
3850        stripe_nr_orig = stripe_nr;
3851        stripe_nr_end = (offset + *length + map->stripe_len - 1) &
3852                        (~(map->stripe_len - 1));
3853        do_div(stripe_nr_end, map->stripe_len);
3854        stripe_end_offset = stripe_nr_end * map->stripe_len -
3855                            (offset + *length);
3856        if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3857                if (rw & REQ_DISCARD)
3858                        num_stripes = min_t(u64, map->num_stripes,
3859                                            stripe_nr_end - stripe_nr_orig);
3860                stripe_index = do_div(stripe_nr, map->num_stripes);
3861        } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3862                if (rw & (REQ_WRITE | REQ_DISCARD))
3863                        num_stripes = map->num_stripes;
3864                else if (mirror_num)
3865                        stripe_index = mirror_num - 1;
3866                else {
3867                        stripe_index = find_live_mirror(map, 0,
3868                                            map->num_stripes,
3869                                            current->pid % map->num_stripes);
3870                        mirror_num = stripe_index + 1;
3871                }
3872
3873        } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3874                if (rw & (REQ_WRITE | REQ_DISCARD)) {
3875                        num_stripes = map->num_stripes;
3876                } else if (mirror_num) {
3877                        stripe_index = mirror_num - 1;
3878                } else {
3879                        mirror_num = 1;
3880                }
3881
3882        } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3883                int factor = map->num_stripes / map->sub_stripes;
3884
3885                stripe_index = do_div(stripe_nr, factor);
3886                stripe_index *= map->sub_stripes;
3887
3888                if (rw & REQ_WRITE)
3889                        num_stripes = map->sub_stripes;
3890                else if (rw & REQ_DISCARD)
3891                        num_stripes = min_t(u64, map->sub_stripes *
3892                                            (stripe_nr_end - stripe_nr_orig),
3893                                            map->num_stripes);
3894                else if (mirror_num)
3895                        stripe_index += mirror_num - 1;
3896                else {
3897                        int old_stripe_index = stripe_index;
3898                        stripe_index = find_live_mirror(map, stripe_index,
3899                                              map->sub_stripes, stripe_index +
3900                                              current->pid % map->sub_stripes);
3901                        mirror_num = stripe_index - old_stripe_index + 1;
3902                }
3903        } else {
3904                /*
3905                 * after this do_div call, stripe_nr is the number of stripes
3906                 * on this device we have to walk to find the data, and
3907                 * stripe_index is the number of our device in the stripe array
3908                 */
3909                stripe_index = do_div(stripe_nr, map->num_stripes);
3910                mirror_num = stripe_index + 1;
3911        }
3912        BUG_ON(stripe_index >= map->num_stripes);
3913
3914        bbio = kzalloc(btrfs_bio_size(num_stripes), GFP_NOFS);
3915        if (!bbio) {
3916                ret = -ENOMEM;
3917                goto out;
3918        }
3919        atomic_set(&bbio->error, 0);
3920
3921        if (rw & REQ_DISCARD) {
3922                int factor = 0;
3923                int sub_stripes = 0;
3924                u64 stripes_per_dev = 0;
3925                u32 remaining_stripes = 0;
3926                u32 last_stripe = 0;
3927
3928                if (map->type &
3929                    (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
3930                        if (map->type & BTRFS_BLOCK_GROUP_RAID0)
3931                                sub_stripes = 1;
3932                        else
3933                                sub_stripes = map->sub_stripes;
3934
3935                        factor = map->num_stripes / sub_stripes;
3936                        stripes_per_dev = div_u64_rem(stripe_nr_end -
3937                                                      stripe_nr_orig,
3938                                                      factor,
3939                                                      &remaining_stripes);
3940                        div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
3941                        last_stripe *= sub_stripes;
3942                }
3943
3944                for (i = 0; i < num_stripes; i++) {
3945                        bbio->stripes[i].physical =
3946                                map->stripes[stripe_index].physical +
3947                                stripe_offset + stripe_nr * map->stripe_len;
3948                        bbio->stripes[i].dev = map->stripes[stripe_index].dev;
3949
3950                        if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
3951                                         BTRFS_BLOCK_GROUP_RAID10)) {
3952                                bbio->stripes[i].length = stripes_per_dev *
3953                                                          map->stripe_len;
3954
3955                                if (i / sub_stripes < remaining_stripes)
3956                                        bbio->stripes[i].length +=
3957                                                map->stripe_len;
3958
3959                                /*
3960                                 * Special for the first stripe and
3961                                 * the last stripe:
3962                                 *
3963                                 * |-------|...|-------|
3964                                 *     |----------|
3965                                 *    off     end_off
3966                                 */
3967                                if (i < sub_stripes)
3968                                        bbio->stripes[i].length -=
3969                                                stripe_offset;
3970
3971                                if (stripe_index >= last_stripe &&
3972                                    stripe_index <= (last_stripe +
3973                                                     sub_stripes - 1))
3974                                        bbio->stripes[i].length -=
3975                                                stripe_end_offset;
3976
3977                                if (i == sub_stripes - 1)
3978                                        stripe_offset = 0;
3979                        } else
3980                                bbio->stripes[i].length = *length;
3981
3982                        stripe_index++;
3983                        if (stripe_index == map->num_stripes) {
3984                                /* This could only happen for RAID0/10 */
3985                                stripe_index = 0;
3986                                stripe_nr++;
3987                        }
3988                }
3989        } else {
3990                for (i = 0; i < num_stripes; i++) {
3991                        bbio->stripes[i].physical =
3992                                map->stripes[stripe_index].physical +
3993                                stripe_offset +
3994                                stripe_nr * map->stripe_len;
3995                        bbio->stripes[i].dev =
3996                                map->stripes[stripe_index].dev;
3997                        stripe_index++;
3998                }
3999        }
4000
4001        if (rw & REQ_WRITE) {
4002                if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4003                                 BTRFS_BLOCK_GROUP_RAID10 |
4004                                 BTRFS_BLOCK_GROUP_DUP)) {
4005                        max_errors = 1;
4006                }
4007        }
4008
4009        *bbio_ret = bbio;
4010        bbio->num_stripes = num_stripes;
4011        bbio->max_errors = max_errors;
4012        bbio->mirror_num = mirror_num;
4013out:
4014        free_extent_map(em);
4015        return ret;
4016}
4017
4018int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
4019                      u64 logical, u64 *length,
4020                      struct btrfs_bio **bbio_ret, int mirror_num)
4021{
4022        return __btrfs_map_block(map_tree, rw, logical, length, bbio_ret,
4023                                 mirror_num);
4024}
4025
4026int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
4027                     u64 chunk_start, u64 physical, u64 devid,
4028                     u64 **logical, int *naddrs, int *stripe_len)
4029{
4030        struct extent_map_tree *em_tree = &map_tree->map_tree;
4031        struct extent_map *em;
4032        struct map_lookup *map;
4033        u64 *buf;
4034        u64 bytenr;
4035        u64 length;
4036        u64 stripe_nr;
4037        int i, j, nr = 0;
4038
4039        read_lock(&em_tree->lock);
4040        em = lookup_extent_mapping(em_tree, chunk_start, 1);
4041        read_unlock(&em_tree->lock);
4042
4043        BUG_ON(!em || em->start != chunk_start);
4044        map = (struct map_lookup *)em->bdev;
4045
4046        length = em->len;
4047        if (map->type & BTRFS_BLOCK_GROUP_RAID10)
4048                do_div(length, map->num_stripes / map->sub_stripes);
4049        else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
4050                do_div(length, map->num_stripes);
4051
4052        buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
4053        BUG_ON(!buf); /* -ENOMEM */
4054
4055        for (i = 0; i < map->num_stripes; i++) {
4056                if (devid && map->stripes[i].dev->devid != devid)
4057                        continue;
4058                if (map->stripes[i].physical > physical ||
4059                    map->stripes[i].physical + length <= physical)
4060                        continue;
4061
4062                stripe_nr = physical - map->stripes[i].physical;
4063                do_div(stripe_nr, map->stripe_len);
4064
4065                if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
4066                        stripe_nr = stripe_nr * map->num_stripes + i;
4067                        do_div(stripe_nr, map->sub_stripes);
4068                } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
4069                        stripe_nr = stripe_nr * map->num_stripes + i;
4070                }
4071                bytenr = chunk_start + stripe_nr * map->stripe_len;
4072                WARN_ON(nr >= map->num_stripes);
4073                for (j = 0; j < nr; j++) {
4074                        if (buf[j] == bytenr)
4075                                break;
4076                }
4077                if (j == nr) {
4078                        WARN_ON(nr >= map->num_stripes);
4079                        buf[nr++] = bytenr;
4080                }
4081        }
4082
4083        *logical = buf;
4084        *naddrs = nr;
4085        *stripe_len = map->stripe_len;
4086
4087        free_extent_map(em);
4088        return 0;
4089}
4090
4091static void *merge_stripe_index_into_bio_private(void *bi_private,
4092                                                 unsigned int stripe_index)
4093{
4094        /*
4095         * with single, dup, RAID0, RAID1 and RAID10, stripe_index is
4096         * at most 1.
4097         * The alternative solution (instead of stealing bits from the
4098         * pointer) would be to allocate an intermediate structure
4099         * that contains the old private pointer plus the stripe_index.
4100         */
4101        BUG_ON((((uintptr_t)bi_private) & 3) != 0);
4102        BUG_ON(stripe_index > 3);
4103        return (void *)(((uintptr_t)bi_private) | stripe_index);
4104}
4105
4106static struct btrfs_bio *extract_bbio_from_bio_private(void *bi_private)
4107{
4108        return (struct btrfs_bio *)(((uintptr_t)bi_private) & ~((uintptr_t)3));
4109}
4110
4111static unsigned int extract_stripe_index_from_bio_private(void *bi_private)
4112{
4113        return (unsigned int)((uintptr_t)bi_private) & 3;
4114}
4115
4116static void btrfs_end_bio(struct bio *bio, int err)
4117{
4118        struct btrfs_bio *bbio = extract_bbio_from_bio_private(bio->bi_private);
4119        int is_orig_bio = 0;
4120
4121        if (err) {
4122                atomic_inc(&bbio->error);
4123                if (err == -EIO || err == -EREMOTEIO) {
4124                        unsigned int stripe_index =
4125                                extract_stripe_index_from_bio_private(
4126                                        bio->bi_private);
4127                        struct btrfs_device *dev;
4128
4129                        BUG_ON(stripe_index >= bbio->num_stripes);
4130                        dev = bbio->stripes[stripe_index].dev;
4131                        if (dev->bdev) {
4132                                if (bio->bi_rw & WRITE)
4133                                        btrfs_dev_stat_inc(dev,
4134                                                BTRFS_DEV_STAT_WRITE_ERRS);
4135                                else
4136                                        btrfs_dev_stat_inc(dev,
4137                                                BTRFS_DEV_STAT_READ_ERRS);
4138                                if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
4139                                        btrfs_dev_stat_inc(dev,
4140                                                BTRFS_DEV_STAT_FLUSH_ERRS);
4141                                btrfs_dev_stat_print_on_error(dev);
4142                        }
4143                }
4144        }
4145
4146        if (bio == bbio->orig_bio)
4147                is_orig_bio = 1;
4148
4149        if (atomic_dec_and_test(&bbio->stripes_pending)) {
4150                if (!is_orig_bio) {
4151                        bio_put(bio);
4152                        bio = bbio->orig_bio;
4153                }
4154                bio->bi_private = bbio->private;
4155                bio->bi_end_io = bbio->end_io;
4156                bio->bi_bdev = (struct block_device *)
4157                                        (unsigned long)bbio->mirror_num;
4158                /* only send an error to the higher layers if it is
4159                 * beyond the tolerance of the multi-bio
4160                 */
4161                if (atomic_read(&bbio->error) > bbio->max_errors) {
4162                        err = -EIO;
4163                } else {
4164                        /*
4165                         * this bio is actually up to date, we didn't
4166                         * go over the max number of errors
4167                         */
4168                        set_bit(BIO_UPTODATE, &bio->bi_flags);
4169                        err = 0;
4170                }
4171                kfree(bbio);
4172
4173                bio_endio(bio, err);
4174        } else if (!is_orig_bio) {
4175                bio_put(bio);
4176        }
4177}
4178
4179struct async_sched {
4180        struct bio *bio;
4181        int rw;
4182        struct btrfs_fs_info *info;
4183        struct btrfs_work work;
4184};
4185
4186/*
4187 * see run_scheduled_bios for a description of why bios are collected for
4188 * async submit.
4189 *
4190 * This will add one bio to the pending list for a device and make sure
4191 * the work struct is scheduled.
4192 */
4193static noinline void schedule_bio(struct btrfs_root *root,
4194                                 struct btrfs_device *device,
4195                                 int rw, struct bio *bio)
4196{
4197        int should_queue = 1;
4198        struct btrfs_pending_bios *pending_bios;
4199
4200        /* don't bother with additional async steps for reads, right now */
4201        if (!(rw & REQ_WRITE)) {
4202                bio_get(bio);
4203                btrfsic_submit_bio(rw, bio);
4204                bio_put(bio);
4205                return;
4206        }
4207
4208        /*
4209         * nr_async_bios allows us to reliably return congestion to the
4210         * higher layers.  Otherwise, the async bio makes it appear we have
4211         * made progress against dirty pages when we've really just put it
4212         * on a queue for later
4213         */
4214        atomic_inc(&root->fs_info->nr_async_bios);
4215        WARN_ON(bio->bi_next);
4216        bio->bi_next = NULL;
4217        bio->bi_rw |= rw;
4218
4219        spin_lock(&device->io_lock);
4220        if (bio->bi_rw & REQ_SYNC)
4221                pending_bios = &device->pending_sync_bios;
4222        else
4223                pending_bios = &device->pending_bios;
4224
4225        if (pending_bios->tail)
4226                pending_bios->tail->bi_next = bio;
4227
4228        pending_bios->tail = bio;
4229        if (!pending_bios->head)
4230                pending_bios->head = bio;
4231        if (device->running_pending)
4232                should_queue = 0;
4233
4234        spin_unlock(&device->io_lock);
4235
4236        if (should_queue)
4237                btrfs_queue_worker(&root->fs_info->submit_workers,
4238                                   &device->work);
4239}
4240
4241int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
4242                  int mirror_num, int async_submit)
4243{
4244        struct btrfs_mapping_tree *map_tree;
4245        struct btrfs_device *dev;
4246        struct bio *first_bio = bio;
4247        u64 logical = (u64)bio->bi_sector << 9;
4248        u64 length = 0;
4249        u64 map_length;
4250        int ret;
4251        int dev_nr = 0;
4252        int total_devs = 1;
4253        struct btrfs_bio *bbio = NULL;
4254
4255        length = bio->bi_size;
4256        map_tree = &root->fs_info->mapping_tree;
4257        map_length = length;
4258
4259        ret = btrfs_map_block(map_tree, rw, logical, &map_length, &bbio,
4260                              mirror_num);
4261        if (ret) /* -ENOMEM */
4262                return ret;
4263
4264        total_devs = bbio->num_stripes;
4265        if (map_length < length) {
4266                printk(KERN_CRIT "btrfs: mapping failed logical %llu bio len %llu "
4267                       "len %llu\n", (unsigned long long)logical,
4268                       (unsigned long long)length,
4269                       (unsigned long long)map_length);
4270                BUG();
4271        }
4272
4273        bbio->orig_bio = first_bio;
4274        bbio->private = first_bio->bi_private;
4275        bbio->end_io = first_bio->bi_end_io;
4276        atomic_set(&bbio->stripes_pending, bbio->num_stripes);
4277
4278        while (dev_nr < total_devs) {
4279                if (dev_nr < total_devs - 1) {
4280                        bio = bio_clone(first_bio, GFP_NOFS);
4281                        BUG_ON(!bio); /* -ENOMEM */
4282                } else {
4283                        bio = first_bio;
4284                }
4285                bio->bi_private = bbio;
4286                bio->bi_private = merge_stripe_index_into_bio_private(
4287                                bio->bi_private, (unsigned int)dev_nr);
4288                bio->bi_end_io = btrfs_end_bio;
4289                bio->bi_sector = bbio->stripes[dev_nr].physical >> 9;
4290                dev = bbio->stripes[dev_nr].dev;
4291                if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
4292#ifdef DEBUG
4293                        struct rcu_string *name;
4294
4295                        rcu_read_lock();
4296                        name = rcu_dereference(dev->name);
4297                        pr_debug("btrfs_map_bio: rw %d, secor=%llu, dev=%lu "
4298                                 "(%s id %llu), size=%u\n", rw,
4299                                 (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
4300                                 name->str, dev->devid, bio->bi_size);
4301                        rcu_read_unlock();
4302#endif
4303                        bio->bi_bdev = dev->bdev;
4304                        if (async_submit)
4305                                schedule_bio(root, dev, rw, bio);
4306                        else
4307                                btrfsic_submit_bio(rw, bio);
4308                } else {
4309                        bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
4310                        bio->bi_sector = logical >> 9;
4311                        bio_endio(bio, -EIO);
4312                }
4313                dev_nr++;
4314        }
4315        return 0;
4316}
4317
4318struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
4319                                       u8 *uuid, u8 *fsid)
4320{
4321        struct btrfs_device *device;
4322        struct btrfs_fs_devices *cur_devices;
4323
4324        cur_devices = root->fs_info->fs_devices;
4325        while (cur_devices) {
4326                if (!fsid ||
4327                    !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4328                        device = __find_device(&cur_devices->devices,
4329                                               devid, uuid);
4330                        if (device)
4331                                return device;
4332                }
4333                cur_devices = cur_devices->seed;
4334        }
4335        return NULL;
4336}
4337
4338static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
4339                                            u64 devid, u8 *dev_uuid)
4340{
4341        struct btrfs_device *device;
4342        struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4343
4344        device = kzalloc(sizeof(*device), GFP_NOFS);
4345        if (!device)
4346                return NULL;
4347        list_add(&device->dev_list,
4348                 &fs_devices->devices);
4349        device->dev_root = root->fs_info->dev_root;
4350        device->devid = devid;
4351        device->work.func = pending_bios_fn;
4352        device->fs_devices = fs_devices;
4353        device->missing = 1;
4354        fs_devices->num_devices++;
4355        fs_devices->missing_devices++;
4356        spin_lock_init(&device->io_lock);
4357        INIT_LIST_HEAD(&device->dev_alloc_list);
4358        memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
4359        return device;
4360}
4361
4362static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
4363                          struct extent_buffer *leaf,
4364                          struct btrfs_chunk *chunk)
4365{
4366        struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4367        struct map_lookup *map;
4368        struct extent_map *em;
4369        u64 logical;
4370        u64 length;
4371        u64 devid;
4372        u8 uuid[BTRFS_UUID_SIZE];
4373        int num_stripes;
4374        int ret;
4375        int i;
4376
4377        logical = key->offset;
4378        length = btrfs_chunk_length(leaf, chunk);
4379
4380        read_lock(&map_tree->map_tree.lock);
4381        em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
4382        read_unlock(&map_tree->map_tree.lock);
4383
4384        /* already mapped? */
4385        if (em && em->start <= logical && em->start + em->len > logical) {
4386                free_extent_map(em);
4387                return 0;
4388        } else if (em) {
4389                free_extent_map(em);
4390        }
4391
4392        em = alloc_extent_map();
4393        if (!em)
4394                return -ENOMEM;
4395        num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
4396        map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4397        if (!map) {
4398                free_extent_map(em);
4399                return -ENOMEM;
4400        }
4401
4402        em->bdev = (struct block_device *)map;
4403        em->start = logical;
4404        em->len = length;
4405        em->block_start = 0;
4406        em->block_len = em->len;
4407
4408        map->num_stripes = num_stripes;
4409        map->io_width = btrfs_chunk_io_width(leaf, chunk);
4410        map->io_align = btrfs_chunk_io_align(leaf, chunk);
4411        map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
4412        map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
4413        map->type = btrfs_chunk_type(leaf, chunk);
4414        map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
4415        for (i = 0; i < num_stripes; i++) {
4416                map->stripes[i].physical =
4417                        btrfs_stripe_offset_nr(leaf, chunk, i);
4418                devid = btrfs_stripe_devid_nr(leaf, chunk, i);
4419                read_extent_buffer(leaf, uuid, (unsigned long)
4420                                   btrfs_stripe_dev_uuid_nr(chunk, i),
4421                                   BTRFS_UUID_SIZE);
4422                map->stripes[i].dev = btrfs_find_device(root, devid, uuid,
4423                                                        NULL);
4424                if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
4425                        kfree(map);
4426                        free_extent_map(em);
4427                        return -EIO;
4428                }
4429                if (!map->stripes[i].dev) {
4430                        map->stripes[i].dev =
4431                                add_missing_dev(root, devid, uuid);
4432                        if (!map->stripes[i].dev) {
4433                                kfree(map);
4434                                free_extent_map(em);
4435                                return -EIO;
4436                        }
4437                }
4438                map->stripes[i].dev->in_fs_metadata = 1;
4439        }
4440
4441        write_lock(&map_tree->map_tree.lock);
4442        ret = add_extent_mapping(&map_tree->map_tree, em);
4443        write_unlock(&map_tree->map_tree.lock);
4444        BUG_ON(ret); /* Tree corruption */
4445        free_extent_map(em);
4446
4447        return 0;
4448}
4449
4450static void fill_device_from_item(struct extent_buffer *leaf,
4451                                 struct btrfs_dev_item *dev_item,
4452                                 struct btrfs_device *device)
4453{
4454        unsigned long ptr;
4455
4456        device->devid = btrfs_device_id(leaf, dev_item);
4457        device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
4458        device->total_bytes = device->disk_total_bytes;
4459        device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
4460        device->type = btrfs_device_type(leaf, dev_item);
4461        device->io_align = btrfs_device_io_align(leaf, dev_item);
4462        device->io_width = btrfs_device_io_width(leaf, dev_item);
4463        device->sector_size = btrfs_device_sector_size(leaf, dev_item);
4464
4465        ptr = (unsigned long)btrfs_device_uuid(dev_item);
4466        read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
4467}
4468
4469static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
4470{
4471        struct btrfs_fs_devices *fs_devices;
4472        int ret;
4473
4474        BUG_ON(!mutex_is_locked(&uuid_mutex));
4475
4476        fs_devices = root->fs_info->fs_devices->seed;
4477        while (fs_devices) {
4478                if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
4479                        ret = 0;
4480                        goto out;
4481                }
4482                fs_devices = fs_devices->seed;
4483        }
4484
4485        fs_devices = find_fsid(fsid);
4486        if (!fs_devices) {
4487                ret = -ENOENT;
4488                goto out;
4489        }
4490
4491        fs_devices = clone_fs_devices(fs_devices);
4492        if (IS_ERR(fs_devices)) {
4493                ret = PTR_ERR(fs_devices);
4494                goto out;
4495        }
4496
4497        ret = __btrfs_open_devices(fs_devices, FMODE_READ,
4498                                   root->fs_info->bdev_holder);
4499        if (ret) {
4500                free_fs_devices(fs_devices);
4501                goto out;
4502        }
4503
4504        if (!fs_devices->seeding) {
4505                __btrfs_close_devices(fs_devices);
4506                free_fs_devices(fs_devices);
4507                ret = -EINVAL;
4508                goto out;
4509        }
4510
4511        fs_devices->seed = root->fs_info->fs_devices->seed;
4512        root->fs_info->fs_devices->seed = fs_devices;
4513out:
4514        return ret;
4515}
4516
4517static int read_one_dev(struct btrfs_root *root,
4518                        struct extent_buffer *leaf,
4519                        struct btrfs_dev_item *dev_item)
4520{
4521        struct btrfs_device *device;
4522        u64 devid;
4523        int ret;
4524        u8 fs_uuid[BTRFS_UUID_SIZE];
4525        u8 dev_uuid[BTRFS_UUID_SIZE];
4526
4527        devid = btrfs_device_id(leaf, dev_item);
4528        read_extent_buffer(leaf, dev_uuid,
4529                           (unsigned long)btrfs_device_uuid(dev_item),
4530                           BTRFS_UUID_SIZE);
4531        read_extent_buffer(leaf, fs_uuid,
4532                           (unsigned long)btrfs_device_fsid(dev_item),
4533                           BTRFS_UUID_SIZE);
4534
4535        if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
4536                ret = open_seed_devices(root, fs_uuid);
4537                if (ret && !btrfs_test_opt(root, DEGRADED))
4538                        return ret;
4539        }
4540
4541        device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
4542        if (!device || !device->bdev) {
4543                if (!btrfs_test_opt(root, DEGRADED))
4544                        return -EIO;
4545
4546                if (!device) {
4547                        printk(KERN_WARNING "warning devid %llu missing\n",
4548                               (unsigned long long)devid);
4549                        device = add_missing_dev(root, devid, dev_uuid);
4550                        if (!device)
4551                                return -ENOMEM;
4552                } else if (!device->missing) {
4553                        /*
4554                         * this happens when a device that was properly setup
4555                         * in the device info lists suddenly goes bad.
4556                         * device->bdev is NULL, and so we have to set
4557                         * device->missing to one here
4558                         */
4559                        root->fs_info->fs_devices->missing_devices++;
4560                        device->missing = 1;
4561                }
4562        }
4563
4564        if (device->fs_devices != root->fs_info->fs_devices) {
4565                BUG_ON(device->writeable);
4566                if (device->generation !=
4567                    btrfs_device_generation(leaf, dev_item))
4568                        return -EINVAL;
4569        }
4570
4571        fill_device_from_item(leaf, dev_item, device);
4572        device->dev_root = root->fs_info->dev_root;
4573        device->in_fs_metadata = 1;
4574        if (device->writeable) {
4575                device->fs_devices->total_rw_bytes += device->total_bytes;
4576                spin_lock(&root->fs_info->free_chunk_lock);
4577                root->fs_info->free_chunk_space += device->total_bytes -
4578                        device->bytes_used;
4579                spin_unlock(&root->fs_info->free_chunk_lock);
4580        }
4581        ret = 0;
4582        return ret;
4583}
4584
4585int btrfs_read_sys_array(struct btrfs_root *root)
4586{
4587        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4588        struct extent_buffer *sb;
4589        struct btrfs_disk_key *disk_key;
4590        struct btrfs_chunk *chunk;
4591        u8 *ptr;
4592        unsigned long sb_ptr;
4593        int ret = 0;
4594        u32 num_stripes;
4595        u32 array_size;
4596        u32 len = 0;
4597        u32 cur;
4598        struct btrfs_key key;
4599
4600        sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
4601                                          BTRFS_SUPER_INFO_SIZE);
4602        if (!sb)
4603                return -ENOMEM;
4604        btrfs_set_buffer_uptodate(sb);
4605        btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
4606        /*
4607         * The sb extent buffer is artifical and just used to read the system array.
4608         * btrfs_set_buffer_uptodate() call does not properly mark all it's
4609         * pages up-to-date when the page is larger: extent does not cover the
4610         * whole page and consequently check_page_uptodate does not find all
4611         * the page's extents up-to-date (the hole beyond sb),
4612         * write_extent_buffer then triggers a WARN_ON.
4613         *
4614         * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
4615         * but sb spans only this function. Add an explicit SetPageUptodate call
4616         * to silence the warning eg. on PowerPC 64.
4617         */
4618        if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
4619                SetPageUptodate(sb->pages[0]);
4620
4621        write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
4622        array_size = btrfs_super_sys_array_size(super_copy);
4623
4624        ptr = super_copy->sys_chunk_array;
4625        sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
4626        cur = 0;
4627
4628        while (cur < array_size) {
4629                disk_key = (struct btrfs_disk_key *)ptr;
4630                btrfs_disk_key_to_cpu(&key, disk_key);
4631
4632                len = sizeof(*disk_key); ptr += len;
4633                sb_ptr += len;
4634                cur += len;
4635
4636                if (key.type == BTRFS_CHUNK_ITEM_KEY) {
4637                        chunk = (struct btrfs_chunk *)sb_ptr;
4638                        ret = read_one_chunk(root, &key, sb, chunk);
4639                        if (ret)
4640                                break;
4641                        num_stripes = btrfs_chunk_num_stripes(sb, chunk);
4642                        len = btrfs_chunk_item_size(num_stripes);
4643                } else {
4644                        ret = -EIO;
4645                        break;
4646                }
4647                ptr += len;
4648                sb_ptr += len;
4649                cur += len;
4650        }
4651        free_extent_buffer(sb);
4652        return ret;
4653}
4654
4655int btrfs_read_chunk_tree(struct btrfs_root *root)
4656{
4657        struct btrfs_path *path;
4658        struct extent_buffer *leaf;
4659        struct btrfs_key key;
4660        struct btrfs_key found_key;
4661        int ret;
4662        int slot;
4663
4664        root = root->fs_info->chunk_root;
4665
4666        path = btrfs_alloc_path();
4667        if (!path)
4668                return -ENOMEM;
4669
4670        mutex_lock(&uuid_mutex);
4671        lock_chunks(root);
4672
4673        /* first we search for all of the device items, and then we
4674         * read in all of the chunk items.  This way we can create chunk
4675         * mappings that reference all of the devices that are afound
4676         */
4677        key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
4678        key.offset = 0;
4679        key.type = 0;
4680again:
4681        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4682        if (ret < 0)
4683                goto error;
4684        while (1) {
4685                leaf = path->nodes[0];
4686                slot = path->slots[0];
4687                if (slot >= btrfs_header_nritems(leaf)) {
4688                        ret = btrfs_next_leaf(root, path);
4689                        if (ret == 0)
4690                                continue;
4691                        if (ret < 0)
4692                                goto error;
4693                        break;
4694                }
4695                btrfs_item_key_to_cpu(leaf, &found_key, slot);
4696                if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
4697                        if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
4698                                break;
4699                        if (found_key.type == BTRFS_DEV_ITEM_KEY) {
4700                                struct btrfs_dev_item *dev_item;
4701                                dev_item = btrfs_item_ptr(leaf, slot,
4702                                                  struct btrfs_dev_item);
4703                                ret = read_one_dev(root, leaf, dev_item);
4704                                if (ret)
4705                                        goto error;
4706                        }
4707                } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
4708                        struct btrfs_chunk *chunk;
4709                        chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
4710                        ret = read_one_chunk(root, &found_key, leaf, chunk);
4711                        if (ret)
4712                                goto error;
4713                }
4714                path->slots[0]++;
4715        }
4716        if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
4717                key.objectid = 0;
4718                btrfs_release_path(path);
4719                goto again;
4720        }
4721        ret = 0;
4722error:
4723        unlock_chunks(root);
4724        mutex_unlock(&uuid_mutex);
4725
4726        btrfs_free_path(path);
4727        return ret;
4728}
4729
4730static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
4731{
4732        int i;
4733
4734        for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4735                btrfs_dev_stat_reset(dev, i);
4736}
4737
4738int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
4739{
4740        struct btrfs_key key;
4741        struct btrfs_key found_key;
4742        struct btrfs_root *dev_root = fs_info->dev_root;
4743        struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
4744        struct extent_buffer *eb;
4745        int slot;
4746        int ret = 0;
4747        struct btrfs_device *device;
4748        struct btrfs_path *path = NULL;
4749        int i;
4750
4751        path = btrfs_alloc_path();
4752        if (!path) {
4753                ret = -ENOMEM;
4754                goto out;
4755        }
4756
4757        mutex_lock(&fs_devices->device_list_mutex);
4758        list_for_each_entry(device, &fs_devices->devices, dev_list) {
4759                int item_size;
4760                struct btrfs_dev_stats_item *ptr;
4761
4762                key.objectid = 0;
4763                key.type = BTRFS_DEV_STATS_KEY;
4764                key.offset = device->devid;
4765                ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
4766                if (ret) {
4767                        __btrfs_reset_dev_stats(device);
4768                        device->dev_stats_valid = 1;
4769                        btrfs_release_path(path);
4770                        continue;
4771                }
4772                slot = path->slots[0];
4773                eb = path->nodes[0];
4774                btrfs_item_key_to_cpu(eb, &found_key, slot);
4775                item_size = btrfs_item_size_nr(eb, slot);
4776
4777                ptr = btrfs_item_ptr(eb, slot,
4778                                     struct btrfs_dev_stats_item);
4779
4780                for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
4781                        if (item_size >= (1 + i) * sizeof(__le64))
4782                                btrfs_dev_stat_set(device, i,
4783                                        btrfs_dev_stats_value(eb, ptr, i));
4784                        else
4785                                btrfs_dev_stat_reset(device, i);
4786                }
4787
4788                device->dev_stats_valid = 1;
4789                btrfs_dev_stat_print_on_load(device);
4790                btrfs_release_path(path);
4791        }
4792        mutex_unlock(&fs_devices->device_list_mutex);
4793
4794out:
4795        btrfs_free_path(path);
4796        return ret < 0 ? ret : 0;
4797}
4798
4799static int update_dev_stat_item(struct btrfs_trans_handle *trans,
4800                                struct btrfs_root *dev_root,
4801                                struct btrfs_device *device)
4802{
4803        struct btrfs_path *path;
4804        struct btrfs_key key;
4805        struct extent_buffer *eb;
4806        struct btrfs_dev_stats_item *ptr;
4807        int ret;
4808        int i;
4809
4810        key.objectid = 0;
4811        key.type = BTRFS_DEV_STATS_KEY;
4812        key.offset = device->devid;
4813
4814        path = btrfs_alloc_path();
4815        BUG_ON(!path);
4816        ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
4817        if (ret < 0) {
4818                printk_in_rcu(KERN_WARNING "btrfs: error %d while searching for dev_stats item for device %s!\n",
4819                              ret, rcu_str_deref(device->name));
4820                goto out;
4821        }
4822
4823        if (ret == 0 &&
4824            btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
4825                /* need to delete old one and insert a new one */
4826                ret = btrfs_del_item(trans, dev_root, path);
4827                if (ret != 0) {
4828                        printk_in_rcu(KERN_WARNING "btrfs: delete too small dev_stats item for device %s failed %d!\n",
4829                                      rcu_str_deref(device->name), ret);
4830                        goto out;
4831                }
4832                ret = 1;
4833        }
4834
4835        if (ret == 1) {
4836                /* need to insert a new item */
4837                btrfs_release_path(path);
4838                ret = btrfs_insert_empty_item(trans, dev_root, path,
4839                                              &key, sizeof(*ptr));
4840                if (ret < 0) {
4841                        printk_in_rcu(KERN_WARNING "btrfs: insert dev_stats item for device %s failed %d!\n",
4842                                      rcu_str_deref(device->name), ret);
4843                        goto out;
4844                }
4845        }
4846
4847        eb = path->nodes[0];
4848        ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
4849        for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4850                btrfs_set_dev_stats_value(eb, ptr, i,
4851                                          btrfs_dev_stat_read(device, i));
4852        btrfs_mark_buffer_dirty(eb);
4853
4854out:
4855        btrfs_free_path(path);
4856        return ret;
4857}
4858
4859/*
4860 * called from commit_transaction. Writes all changed device stats to disk.
4861 */
4862int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
4863                        struct btrfs_fs_info *fs_info)
4864{
4865        struct btrfs_root *dev_root = fs_info->dev_root;
4866        struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
4867        struct btrfs_device *device;
4868        int ret = 0;
4869
4870        mutex_lock(&fs_devices->device_list_mutex);
4871        list_for_each_entry(device, &fs_devices->devices, dev_list) {
4872                if (!device->dev_stats_valid || !device->dev_stats_dirty)
4873                        continue;
4874
4875                ret = update_dev_stat_item(trans, dev_root, device);
4876                if (!ret)
4877                        device->dev_stats_dirty = 0;
4878        }
4879        mutex_unlock(&fs_devices->device_list_mutex);
4880
4881        return ret;
4882}
4883
4884void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
4885{
4886        btrfs_dev_stat_inc(dev, index);
4887        btrfs_dev_stat_print_on_error(dev);
4888}
4889
4890void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
4891{
4892        if (!dev->dev_stats_valid)
4893                return;
4894        printk_ratelimited_in_rcu(KERN_ERR
4895                           "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
4896                           rcu_str_deref(dev->name),
4897                           btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
4898                           btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
4899                           btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
4900                           btrfs_dev_stat_read(dev,
4901                                               BTRFS_DEV_STAT_CORRUPTION_ERRS),
4902                           btrfs_dev_stat_read(dev,
4903                                               BTRFS_DEV_STAT_GENERATION_ERRS));
4904}
4905
4906static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
4907{
4908        int i;
4909
4910        for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4911                if (btrfs_dev_stat_read(dev, i) != 0)
4912                        break;
4913        if (i == BTRFS_DEV_STAT_VALUES_MAX)
4914                return; /* all values == 0, suppress message */
4915
4916        printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
4917               rcu_str_deref(dev->name),
4918               btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
4919               btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
4920               btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
4921               btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
4922               btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
4923}
4924
4925int btrfs_get_dev_stats(struct btrfs_root *root,
4926                        struct btrfs_ioctl_get_dev_stats *stats)
4927{
4928        struct btrfs_device *dev;
4929        struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
4930        int i;
4931
4932        mutex_lock(&fs_devices->device_list_mutex);
4933        dev = btrfs_find_device(root, stats->devid, NULL, NULL);
4934        mutex_unlock(&fs_devices->device_list_mutex);
4935
4936        if (!dev) {
4937                printk(KERN_WARNING
4938                       "btrfs: get dev_stats failed, device not found\n");
4939                return -ENODEV;
4940        } else if (!dev->dev_stats_valid) {
4941                printk(KERN_WARNING
4942                       "btrfs: get dev_stats failed, not yet valid\n");
4943                return -ENODEV;
4944        } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
4945                for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
4946                        if (stats->nr_items > i)
4947                                stats->values[i] =
4948                                        btrfs_dev_stat_read_and_reset(dev, i);
4949                        else
4950                                btrfs_dev_stat_reset(dev, i);
4951                }
4952        } else {
4953                for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
4954                        if (stats->nr_items > i)
4955                                stats->values[i] = btrfs_dev_stat_read(dev, i);
4956        }
4957        if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
4958                stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
4959        return 0;
4960}
4961
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.