linux/drivers/target/target_core_file.c
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   1/*******************************************************************************
   2 * Filename:  target_core_file.c
   3 *
   4 * This file contains the Storage Engine <-> FILEIO transport specific functions
   5 *
   6 * Copyright (c) 2005 PyX Technologies, Inc.
   7 * Copyright (c) 2005-2006 SBE, Inc.  All Rights Reserved.
   8 * Copyright (c) 2007-2010 Rising Tide Systems
   9 * Copyright (c) 2008-2010 Linux-iSCSI.org
  10 *
  11 * Nicholas A. Bellinger <nab@kernel.org>
  12 *
  13 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2 of the License, or
  16 * (at your option) any later version.
  17 *
  18 * This program is distributed in the hope that it will be useful,
  19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 * GNU General Public License for more details.
  22 *
  23 * You should have received a copy of the GNU General Public License
  24 * along with this program; if not, write to the Free Software
  25 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26 *
  27 ******************************************************************************/
  28
  29#include <linux/string.h>
  30#include <linux/parser.h>
  31#include <linux/timer.h>
  32#include <linux/blkdev.h>
  33#include <linux/slab.h>
  34#include <linux/spinlock.h>
  35#include <linux/module.h>
  36#include <scsi/scsi.h>
  37#include <scsi/scsi_host.h>
  38
  39#include <target/target_core_base.h>
  40#include <target/target_core_backend.h>
  41
  42#include "target_core_file.h"
  43
  44static struct se_subsystem_api fileio_template;
  45
  46/*      fd_attach_hba(): (Part of se_subsystem_api_t template)
  47 *
  48 *
  49 */
  50static int fd_attach_hba(struct se_hba *hba, u32 host_id)
  51{
  52        struct fd_host *fd_host;
  53
  54        fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
  55        if (!fd_host) {
  56                pr_err("Unable to allocate memory for struct fd_host\n");
  57                return -ENOMEM;
  58        }
  59
  60        fd_host->fd_host_id = host_id;
  61
  62        hba->hba_ptr = fd_host;
  63
  64        pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
  65                " Target Core Stack %s\n", hba->hba_id, FD_VERSION,
  66                TARGET_CORE_MOD_VERSION);
  67        pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic"
  68                " MaxSectors: %u\n",
  69                hba->hba_id, fd_host->fd_host_id, FD_MAX_SECTORS);
  70
  71        return 0;
  72}
  73
  74static void fd_detach_hba(struct se_hba *hba)
  75{
  76        struct fd_host *fd_host = hba->hba_ptr;
  77
  78        pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
  79                " Target Core\n", hba->hba_id, fd_host->fd_host_id);
  80
  81        kfree(fd_host);
  82        hba->hba_ptr = NULL;
  83}
  84
  85static void *fd_allocate_virtdevice(struct se_hba *hba, const char *name)
  86{
  87        struct fd_dev *fd_dev;
  88        struct fd_host *fd_host = hba->hba_ptr;
  89
  90        fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
  91        if (!fd_dev) {
  92                pr_err("Unable to allocate memory for struct fd_dev\n");
  93                return NULL;
  94        }
  95
  96        fd_dev->fd_host = fd_host;
  97
  98        pr_debug("FILEIO: Allocated fd_dev for %p\n", name);
  99
 100        return fd_dev;
 101}
 102
 103/*      fd_create_virtdevice(): (Part of se_subsystem_api_t template)
 104 *
 105 *
 106 */
 107static struct se_device *fd_create_virtdevice(
 108        struct se_hba *hba,
 109        struct se_subsystem_dev *se_dev,
 110        void *p)
 111{
 112        struct se_device *dev;
 113        struct se_dev_limits dev_limits;
 114        struct queue_limits *limits;
 115        struct fd_dev *fd_dev = p;
 116        struct fd_host *fd_host = hba->hba_ptr;
 117        struct file *file;
 118        struct inode *inode = NULL;
 119        int dev_flags = 0, flags, ret = -EINVAL;
 120
 121        memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 122
 123        /*
 124         * Use O_DSYNC by default instead of O_SYNC to forgo syncing
 125         * of pure timestamp updates.
 126         */
 127        flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
 128        /*
 129         * Optionally allow fd_buffered_io=1 to be enabled for people
 130         * who want use the fs buffer cache as an WriteCache mechanism.
 131         *
 132         * This means that in event of a hard failure, there is a risk
 133         * of silent data-loss if the SCSI client has *not* performed a
 134         * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
 135         * to write-out the entire device cache.
 136         */
 137        if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
 138                pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n");
 139                flags &= ~O_DSYNC;
 140        }
 141
 142        file = filp_open(fd_dev->fd_dev_name, flags, 0600);
 143        if (IS_ERR(file)) {
 144                pr_err("filp_open(%s) failed\n", fd_dev->fd_dev_name);
 145                ret = PTR_ERR(file);
 146                goto fail;
 147        }
 148        fd_dev->fd_file = file;
 149        /*
 150         * If using a block backend with this struct file, we extract
 151         * fd_dev->fd_[block,dev]_size from struct block_device.
 152         *
 153         * Otherwise, we use the passed fd_size= from configfs
 154         */
 155        inode = file->f_mapping->host;
 156        if (S_ISBLK(inode->i_mode)) {
 157                struct request_queue *q;
 158                unsigned long long dev_size;
 159                /*
 160                 * Setup the local scope queue_limits from struct request_queue->limits
 161                 * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 162                 */
 163                q = bdev_get_queue(inode->i_bdev);
 164                limits = &dev_limits.limits;
 165                limits->logical_block_size = bdev_logical_block_size(inode->i_bdev);
 166                limits->max_hw_sectors = queue_max_hw_sectors(q);
 167                limits->max_sectors = queue_max_sectors(q);
 168                /*
 169                 * Determine the number of bytes from i_size_read() minus
 170                 * one (1) logical sector from underlying struct block_device
 171                 */
 172                fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
 173                dev_size = (i_size_read(file->f_mapping->host) -
 174                                       fd_dev->fd_block_size);
 175
 176                pr_debug("FILEIO: Using size: %llu bytes from struct"
 177                        " block_device blocks: %llu logical_block_size: %d\n",
 178                        dev_size, div_u64(dev_size, fd_dev->fd_block_size),
 179                        fd_dev->fd_block_size);
 180        } else {
 181                if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
 182                        pr_err("FILEIO: Missing fd_dev_size="
 183                                " parameter, and no backing struct"
 184                                " block_device\n");
 185                        goto fail;
 186                }
 187
 188                limits = &dev_limits.limits;
 189                limits->logical_block_size = FD_BLOCKSIZE;
 190                limits->max_hw_sectors = FD_MAX_SECTORS;
 191                limits->max_sectors = FD_MAX_SECTORS;
 192                fd_dev->fd_block_size = FD_BLOCKSIZE;
 193        }
 194
 195        dev_limits.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
 196        dev_limits.queue_depth = FD_DEVICE_QUEUE_DEPTH;
 197
 198        dev = transport_add_device_to_core_hba(hba, &fileio_template,
 199                                se_dev, dev_flags, fd_dev,
 200                                &dev_limits, "FILEIO", FD_VERSION);
 201        if (!dev)
 202                goto fail;
 203
 204        if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
 205                pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
 206                        " with FDBD_HAS_BUFFERED_IO_WCE\n");
 207                dev->se_sub_dev->se_dev_attrib.emulate_write_cache = 1;
 208        }
 209
 210        fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
 211        fd_dev->fd_queue_depth = dev->queue_depth;
 212
 213        pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
 214                " %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
 215                        fd_dev->fd_dev_name, fd_dev->fd_dev_size);
 216
 217        return dev;
 218fail:
 219        if (fd_dev->fd_file) {
 220                filp_close(fd_dev->fd_file, NULL);
 221                fd_dev->fd_file = NULL;
 222        }
 223        return ERR_PTR(ret);
 224}
 225
 226/*      fd_free_device(): (Part of se_subsystem_api_t template)
 227 *
 228 *
 229 */
 230static void fd_free_device(void *p)
 231{
 232        struct fd_dev *fd_dev = p;
 233
 234        if (fd_dev->fd_file) {
 235                filp_close(fd_dev->fd_file, NULL);
 236                fd_dev->fd_file = NULL;
 237        }
 238
 239        kfree(fd_dev);
 240}
 241
 242static int fd_do_readv(struct se_cmd *cmd, struct scatterlist *sgl,
 243                u32 sgl_nents)
 244{
 245        struct se_device *se_dev = cmd->se_dev;
 246        struct fd_dev *dev = se_dev->dev_ptr;
 247        struct file *fd = dev->fd_file;
 248        struct scatterlist *sg;
 249        struct iovec *iov;
 250        mm_segment_t old_fs;
 251        loff_t pos = (cmd->t_task_lba *
 252                      se_dev->se_sub_dev->se_dev_attrib.block_size);
 253        int ret = 0, i;
 254
 255        iov = kzalloc(sizeof(struct iovec) * sgl_nents, GFP_KERNEL);
 256        if (!iov) {
 257                pr_err("Unable to allocate fd_do_readv iov[]\n");
 258                return -ENOMEM;
 259        }
 260
 261        for_each_sg(sgl, sg, sgl_nents, i) {
 262                iov[i].iov_len = sg->length;
 263                iov[i].iov_base = sg_virt(sg);
 264        }
 265
 266        old_fs = get_fs();
 267        set_fs(get_ds());
 268        ret = vfs_readv(fd, &iov[0], sgl_nents, &pos);
 269        set_fs(old_fs);
 270
 271        kfree(iov);
 272        /*
 273         * Return zeros and GOOD status even if the READ did not return
 274         * the expected virt_size for struct file w/o a backing struct
 275         * block_device.
 276         */
 277        if (S_ISBLK(fd->f_dentry->d_inode->i_mode)) {
 278                if (ret < 0 || ret != cmd->data_length) {
 279                        pr_err("vfs_readv() returned %d,"
 280                                " expecting %d for S_ISBLK\n", ret,
 281                                (int)cmd->data_length);
 282                        return (ret < 0 ? ret : -EINVAL);
 283                }
 284        } else {
 285                if (ret < 0) {
 286                        pr_err("vfs_readv() returned %d for non"
 287                                " S_ISBLK\n", ret);
 288                        return ret;
 289                }
 290        }
 291
 292        return 1;
 293}
 294
 295static int fd_do_writev(struct se_cmd *cmd, struct scatterlist *sgl,
 296                u32 sgl_nents)
 297{
 298        struct se_device *se_dev = cmd->se_dev;
 299        struct fd_dev *dev = se_dev->dev_ptr;
 300        struct file *fd = dev->fd_file;
 301        struct scatterlist *sg;
 302        struct iovec *iov;
 303        mm_segment_t old_fs;
 304        loff_t pos = (cmd->t_task_lba *
 305                      se_dev->se_sub_dev->se_dev_attrib.block_size);
 306        int ret, i = 0;
 307
 308        iov = kzalloc(sizeof(struct iovec) * sgl_nents, GFP_KERNEL);
 309        if (!iov) {
 310                pr_err("Unable to allocate fd_do_writev iov[]\n");
 311                return -ENOMEM;
 312        }
 313
 314        for_each_sg(sgl, sg, sgl_nents, i) {
 315                iov[i].iov_len = sg->length;
 316                iov[i].iov_base = sg_virt(sg);
 317        }
 318
 319        old_fs = get_fs();
 320        set_fs(get_ds());
 321        ret = vfs_writev(fd, &iov[0], sgl_nents, &pos);
 322        set_fs(old_fs);
 323
 324        kfree(iov);
 325
 326        if (ret < 0 || ret != cmd->data_length) {
 327                pr_err("vfs_writev() returned %d\n", ret);
 328                return (ret < 0 ? ret : -EINVAL);
 329        }
 330
 331        return 1;
 332}
 333
 334static int fd_execute_sync_cache(struct se_cmd *cmd)
 335{
 336        struct se_device *dev = cmd->se_dev;
 337        struct fd_dev *fd_dev = dev->dev_ptr;
 338        int immed = (cmd->t_task_cdb[1] & 0x2);
 339        loff_t start, end;
 340        int ret;
 341
 342        /*
 343         * If the Immediate bit is set, queue up the GOOD response
 344         * for this SYNCHRONIZE_CACHE op
 345         */
 346        if (immed)
 347                target_complete_cmd(cmd, SAM_STAT_GOOD);
 348
 349        /*
 350         * Determine if we will be flushing the entire device.
 351         */
 352        if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
 353                start = 0;
 354                end = LLONG_MAX;
 355        } else {
 356                start = cmd->t_task_lba * dev->se_sub_dev->se_dev_attrib.block_size;
 357                if (cmd->data_length)
 358                        end = start + cmd->data_length;
 359                else
 360                        end = LLONG_MAX;
 361        }
 362
 363        ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 364        if (ret != 0)
 365                pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
 366
 367        if (immed)
 368                return 0;
 369
 370        if (ret) {
 371                cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 372                target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 373        } else {
 374                target_complete_cmd(cmd, SAM_STAT_GOOD);
 375        }
 376
 377        return 0;
 378}
 379
 380static int fd_execute_rw(struct se_cmd *cmd)
 381{
 382        struct scatterlist *sgl = cmd->t_data_sg;
 383        u32 sgl_nents = cmd->t_data_nents;
 384        enum dma_data_direction data_direction = cmd->data_direction;
 385        struct se_device *dev = cmd->se_dev;
 386        int ret = 0;
 387
 388        /*
 389         * Call vectorized fileio functions to map struct scatterlist
 390         * physical memory addresses to struct iovec virtual memory.
 391         */
 392        if (data_direction == DMA_FROM_DEVICE) {
 393                ret = fd_do_readv(cmd, sgl, sgl_nents);
 394        } else {
 395                ret = fd_do_writev(cmd, sgl, sgl_nents);
 396                /*
 397                 * Perform implict vfs_fsync_range() for fd_do_writev() ops
 398                 * for SCSI WRITEs with Forced Unit Access (FUA) set.
 399                 * Allow this to happen independent of WCE=0 setting.
 400                 */
 401                if (ret > 0 &&
 402                    dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 403                    (cmd->se_cmd_flags & SCF_FUA)) {
 404                        struct fd_dev *fd_dev = dev->dev_ptr;
 405                        loff_t start = cmd->t_task_lba *
 406                                dev->se_sub_dev->se_dev_attrib.block_size;
 407                        loff_t end = start + cmd->data_length;
 408
 409                        vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 410                }
 411        }
 412
 413        if (ret < 0) {
 414                cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 415                return ret;
 416        }
 417        if (ret)
 418                target_complete_cmd(cmd, SAM_STAT_GOOD);
 419        return 0;
 420}
 421
 422enum {
 423        Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
 424};
 425
 426static match_table_t tokens = {
 427        {Opt_fd_dev_name, "fd_dev_name=%s"},
 428        {Opt_fd_dev_size, "fd_dev_size=%s"},
 429        {Opt_fd_buffered_io, "fd_buffered_io=%d"},
 430        {Opt_err, NULL}
 431};
 432
 433static ssize_t fd_set_configfs_dev_params(
 434        struct se_hba *hba,
 435        struct se_subsystem_dev *se_dev,
 436        const char *page, ssize_t count)
 437{
 438        struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 439        char *orig, *ptr, *arg_p, *opts;
 440        substring_t args[MAX_OPT_ARGS];
 441        int ret = 0, arg, token;
 442
 443        opts = kstrdup(page, GFP_KERNEL);
 444        if (!opts)
 445                return -ENOMEM;
 446
 447        orig = opts;
 448
 449        while ((ptr = strsep(&opts, ",\n")) != NULL) {
 450                if (!*ptr)
 451                        continue;
 452
 453                token = match_token(ptr, tokens, args);
 454                switch (token) {
 455                case Opt_fd_dev_name:
 456                        if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
 457                                FD_MAX_DEV_NAME) == 0) {
 458                                ret = -EINVAL;
 459                                break;
 460                        }
 461                        pr_debug("FILEIO: Referencing Path: %s\n",
 462                                        fd_dev->fd_dev_name);
 463                        fd_dev->fbd_flags |= FBDF_HAS_PATH;
 464                        break;
 465                case Opt_fd_dev_size:
 466                        arg_p = match_strdup(&args[0]);
 467                        if (!arg_p) {
 468                                ret = -ENOMEM;
 469                                break;
 470                        }
 471                        ret = strict_strtoull(arg_p, 0, &fd_dev->fd_dev_size);
 472                        kfree(arg_p);
 473                        if (ret < 0) {
 474                                pr_err("strict_strtoull() failed for"
 475                                                " fd_dev_size=\n");
 476                                goto out;
 477                        }
 478                        pr_debug("FILEIO: Referencing Size: %llu"
 479                                        " bytes\n", fd_dev->fd_dev_size);
 480                        fd_dev->fbd_flags |= FBDF_HAS_SIZE;
 481                        break;
 482                case Opt_fd_buffered_io:
 483                        match_int(args, &arg);
 484                        if (arg != 1) {
 485                                pr_err("bogus fd_buffered_io=%d value\n", arg);
 486                                ret = -EINVAL;
 487                                goto out;
 488                        }
 489
 490                        pr_debug("FILEIO: Using buffered I/O"
 491                                " operations for struct fd_dev\n");
 492
 493                        fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
 494                        break;
 495                default:
 496                        break;
 497                }
 498        }
 499
 500out:
 501        kfree(orig);
 502        return (!ret) ? count : ret;
 503}
 504
 505static ssize_t fd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
 506{
 507        struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 508
 509        if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
 510                pr_err("Missing fd_dev_name=\n");
 511                return -EINVAL;
 512        }
 513
 514        return 0;
 515}
 516
 517static ssize_t fd_show_configfs_dev_params(
 518        struct se_hba *hba,
 519        struct se_subsystem_dev *se_dev,
 520        char *b)
 521{
 522        struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 523        ssize_t bl = 0;
 524
 525        bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
 526        bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s\n",
 527                fd_dev->fd_dev_name, fd_dev->fd_dev_size,
 528                (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ?
 529                "Buffered-WCE" : "O_DSYNC");
 530        return bl;
 531}
 532
 533/*      fd_get_device_rev(): (Part of se_subsystem_api_t template)
 534 *
 535 *
 536 */
 537static u32 fd_get_device_rev(struct se_device *dev)
 538{
 539        return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 540}
 541
 542/*      fd_get_device_type(): (Part of se_subsystem_api_t template)
 543 *
 544 *
 545 */
 546static u32 fd_get_device_type(struct se_device *dev)
 547{
 548        return TYPE_DISK;
 549}
 550
 551static sector_t fd_get_blocks(struct se_device *dev)
 552{
 553        struct fd_dev *fd_dev = dev->dev_ptr;
 554        struct file *f = fd_dev->fd_file;
 555        struct inode *i = f->f_mapping->host;
 556        unsigned long long dev_size;
 557        /*
 558         * When using a file that references an underlying struct block_device,
 559         * ensure dev_size is always based on the current inode size in order
 560         * to handle underlying block_device resize operations.
 561         */
 562        if (S_ISBLK(i->i_mode))
 563                dev_size = (i_size_read(i) - fd_dev->fd_block_size);
 564        else
 565                dev_size = fd_dev->fd_dev_size;
 566
 567        return div_u64(dev_size, dev->se_sub_dev->se_dev_attrib.block_size);
 568}
 569
 570static struct spc_ops fd_spc_ops = {
 571        .execute_rw             = fd_execute_rw,
 572        .execute_sync_cache     = fd_execute_sync_cache,
 573};
 574
 575static int fd_parse_cdb(struct se_cmd *cmd)
 576{
 577        return sbc_parse_cdb(cmd, &fd_spc_ops);
 578}
 579
 580static struct se_subsystem_api fileio_template = {
 581        .name                   = "fileio",
 582        .owner                  = THIS_MODULE,
 583        .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 584        .write_cache_emulated   = 1,
 585        .fua_write_emulated     = 1,
 586        .attach_hba             = fd_attach_hba,
 587        .detach_hba             = fd_detach_hba,
 588        .allocate_virtdevice    = fd_allocate_virtdevice,
 589        .create_virtdevice      = fd_create_virtdevice,
 590        .free_device            = fd_free_device,
 591        .parse_cdb              = fd_parse_cdb,
 592        .check_configfs_dev_params = fd_check_configfs_dev_params,
 593        .set_configfs_dev_params = fd_set_configfs_dev_params,
 594        .show_configfs_dev_params = fd_show_configfs_dev_params,
 595        .get_device_rev         = fd_get_device_rev,
 596        .get_device_type        = fd_get_device_type,
 597        .get_blocks             = fd_get_blocks,
 598};
 599
 600static int __init fileio_module_init(void)
 601{
 602        return transport_subsystem_register(&fileio_template);
 603}
 604
 605static void fileio_module_exit(void)
 606{
 607        transport_subsystem_release(&fileio_template);
 608}
 609
 610MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
 611MODULE_AUTHOR("nab@Linux-iSCSI.org");
 612MODULE_LICENSE("GPL");
 613
 614module_init(fileio_module_init);
 615module_exit(fileio_module_exit);
 616
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