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 * (c) Copyright 2005-2012 RisingTide Systems LLC.
   7 *
   8 * Nicholas A. Bellinger <nab@kernel.org>
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published by
  12 * the Free Software Foundation; either version 2 of the License, or
  13 * (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23 *
  24 ******************************************************************************/
  25
  26#include <linux/string.h>
  27#include <linux/parser.h>
  28#include <linux/timer.h>
  29#include <linux/blkdev.h>
  30#include <linux/slab.h>
  31#include <linux/spinlock.h>
  32#include <linux/module.h>
  33#include <scsi/scsi.h>
  34#include <scsi/scsi_host.h>
  35
  36#include <target/target_core_base.h>
  37#include <target/target_core_backend.h>
  38
  39#include "target_core_file.h"
  40
  41static inline struct fd_dev *FD_DEV(struct se_device *dev)
  42{
  43        return container_of(dev, struct fd_dev, dev);
  44}
  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 struct se_device *fd_alloc_device(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->dev;
 101}
 102
 103static int fd_configure_device(struct se_device *dev)
 104{
 105        struct fd_dev *fd_dev = FD_DEV(dev);
 106        struct fd_host *fd_host = dev->se_hba->hba_ptr;
 107        struct file *file;
 108        struct inode *inode = NULL;
 109        int flags, ret = -EINVAL;
 110
 111        if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
 112                pr_err("Missing fd_dev_name=\n");
 113                return -EINVAL;
 114        }
 115
 116        /*
 117         * Use O_DSYNC by default instead of O_SYNC to forgo syncing
 118         * of pure timestamp updates.
 119         */
 120        flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
 121
 122        /*
 123         * Optionally allow fd_buffered_io=1 to be enabled for people
 124         * who want use the fs buffer cache as an WriteCache mechanism.
 125         *
 126         * This means that in event of a hard failure, there is a risk
 127         * of silent data-loss if the SCSI client has *not* performed a
 128         * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
 129         * to write-out the entire device cache.
 130         */
 131        if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
 132                pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n");
 133                flags &= ~O_DSYNC;
 134        }
 135
 136        file = filp_open(fd_dev->fd_dev_name, flags, 0600);
 137        if (IS_ERR(file)) {
 138                pr_err("filp_open(%s) failed\n", fd_dev->fd_dev_name);
 139                ret = PTR_ERR(file);
 140                goto fail;
 141        }
 142        fd_dev->fd_file = file;
 143        /*
 144         * If using a block backend with this struct file, we extract
 145         * fd_dev->fd_[block,dev]_size from struct block_device.
 146         *
 147         * Otherwise, we use the passed fd_size= from configfs
 148         */
 149        inode = file->f_mapping->host;
 150        if (S_ISBLK(inode->i_mode)) {
 151                struct request_queue *q = bdev_get_queue(inode->i_bdev);
 152                unsigned long long dev_size;
 153
 154                dev->dev_attrib.hw_block_size =
 155                        bdev_logical_block_size(inode->i_bdev);
 156                dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
 157
 158                /*
 159                 * Determine the number of bytes from i_size_read() minus
 160                 * one (1) logical sector from underlying struct block_device
 161                 */
 162                dev_size = (i_size_read(file->f_mapping->host) -
 163                                       fd_dev->fd_block_size);
 164
 165                pr_debug("FILEIO: Using size: %llu bytes from struct"
 166                        " block_device blocks: %llu logical_block_size: %d\n",
 167                        dev_size, div_u64(dev_size, fd_dev->fd_block_size),
 168                        fd_dev->fd_block_size);
 169        } else {
 170                if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
 171                        pr_err("FILEIO: Missing fd_dev_size="
 172                                " parameter, and no backing struct"
 173                                " block_device\n");
 174                        goto fail;
 175                }
 176
 177                dev->dev_attrib.hw_block_size = FD_BLOCKSIZE;
 178                dev->dev_attrib.hw_max_sectors = FD_MAX_SECTORS;
 179        }
 180
 181        fd_dev->fd_block_size = dev->dev_attrib.hw_block_size;
 182
 183        dev->dev_attrib.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
 184
 185        if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
 186                pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
 187                        " with FDBD_HAS_BUFFERED_IO_WCE\n");
 188                dev->dev_attrib.emulate_write_cache = 1;
 189        }
 190
 191        fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
 192        fd_dev->fd_queue_depth = dev->queue_depth;
 193
 194        pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
 195                " %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
 196                        fd_dev->fd_dev_name, fd_dev->fd_dev_size);
 197
 198        return 0;
 199fail:
 200        if (fd_dev->fd_file) {
 201                filp_close(fd_dev->fd_file, NULL);
 202                fd_dev->fd_file = NULL;
 203        }
 204        return ret;
 205}
 206
 207static void fd_free_device(struct se_device *dev)
 208{
 209        struct fd_dev *fd_dev = FD_DEV(dev);
 210
 211        if (fd_dev->fd_file) {
 212                filp_close(fd_dev->fd_file, NULL);
 213                fd_dev->fd_file = NULL;
 214        }
 215
 216        kfree(fd_dev);
 217}
 218
 219static int fd_do_rw(struct se_cmd *cmd, struct scatterlist *sgl,
 220                u32 sgl_nents, int is_write)
 221{
 222        struct se_device *se_dev = cmd->se_dev;
 223        struct fd_dev *dev = FD_DEV(se_dev);
 224        struct file *fd = dev->fd_file;
 225        struct scatterlist *sg;
 226        struct iovec *iov;
 227        mm_segment_t old_fs;
 228        loff_t pos = (cmd->t_task_lba * se_dev->dev_attrib.block_size);
 229        int ret = 0, i;
 230
 231        iov = kzalloc(sizeof(struct iovec) * sgl_nents, GFP_KERNEL);
 232        if (!iov) {
 233                pr_err("Unable to allocate fd_do_readv iov[]\n");
 234                return -ENOMEM;
 235        }
 236
 237        for_each_sg(sgl, sg, sgl_nents, i) {
 238                iov[i].iov_len = sg->length;
 239                iov[i].iov_base = kmap(sg_page(sg)) + sg->offset;
 240        }
 241
 242        old_fs = get_fs();
 243        set_fs(get_ds());
 244
 245        if (is_write)
 246                ret = vfs_writev(fd, &iov[0], sgl_nents, &pos);
 247        else
 248                ret = vfs_readv(fd, &iov[0], sgl_nents, &pos);
 249
 250        set_fs(old_fs);
 251
 252        for_each_sg(sgl, sg, sgl_nents, i)
 253                kunmap(sg_page(sg));
 254
 255        kfree(iov);
 256
 257        if (is_write) {
 258                if (ret < 0 || ret != cmd->data_length) {
 259                        pr_err("%s() write returned %d\n", __func__, ret);
 260                        return (ret < 0 ? ret : -EINVAL);
 261                }
 262        } else {
 263                /*
 264                 * Return zeros and GOOD status even if the READ did not return
 265                 * the expected virt_size for struct file w/o a backing struct
 266                 * block_device.
 267                 */
 268                if (S_ISBLK(fd->f_dentry->d_inode->i_mode)) {
 269                        if (ret < 0 || ret != cmd->data_length) {
 270                                pr_err("%s() returned %d, expecting %u for "
 271                                                "S_ISBLK\n", __func__, ret,
 272                                                cmd->data_length);
 273                                return (ret < 0 ? ret : -EINVAL);
 274                        }
 275                } else {
 276                        if (ret < 0) {
 277                                pr_err("%s() returned %d for non S_ISBLK\n",
 278                                                __func__, ret);
 279                                return ret;
 280                        }
 281                }
 282        }
 283        return 1;
 284}
 285
 286static sense_reason_t
 287fd_execute_sync_cache(struct se_cmd *cmd)
 288{
 289        struct se_device *dev = cmd->se_dev;
 290        struct fd_dev *fd_dev = FD_DEV(dev);
 291        int immed = (cmd->t_task_cdb[1] & 0x2);
 292        loff_t start, end;
 293        int ret;
 294
 295        /*
 296         * If the Immediate bit is set, queue up the GOOD response
 297         * for this SYNCHRONIZE_CACHE op
 298         */
 299        if (immed)
 300                target_complete_cmd(cmd, SAM_STAT_GOOD);
 301
 302        /*
 303         * Determine if we will be flushing the entire device.
 304         */
 305        if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
 306                start = 0;
 307                end = LLONG_MAX;
 308        } else {
 309                start = cmd->t_task_lba * dev->dev_attrib.block_size;
 310                if (cmd->data_length)
 311                        end = start + cmd->data_length;
 312                else
 313                        end = LLONG_MAX;
 314        }
 315
 316        ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 317        if (ret != 0)
 318                pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
 319
 320        if (immed)
 321                return 0;
 322
 323        if (ret)
 324                target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 325        else
 326                target_complete_cmd(cmd, SAM_STAT_GOOD);
 327
 328        return 0;
 329}
 330
 331static sense_reason_t
 332fd_execute_rw(struct se_cmd *cmd)
 333{
 334        struct scatterlist *sgl = cmd->t_data_sg;
 335        u32 sgl_nents = cmd->t_data_nents;
 336        enum dma_data_direction data_direction = cmd->data_direction;
 337        struct se_device *dev = cmd->se_dev;
 338        int ret = 0;
 339
 340        /*
 341         * Call vectorized fileio functions to map struct scatterlist
 342         * physical memory addresses to struct iovec virtual memory.
 343         */
 344        if (data_direction == DMA_FROM_DEVICE) {
 345                ret = fd_do_rw(cmd, sgl, sgl_nents, 0);
 346        } else {
 347                ret = fd_do_rw(cmd, sgl, sgl_nents, 1);
 348                /*
 349                 * Perform implict vfs_fsync_range() for fd_do_writev() ops
 350                 * for SCSI WRITEs with Forced Unit Access (FUA) set.
 351                 * Allow this to happen independent of WCE=0 setting.
 352                 */
 353                if (ret > 0 &&
 354                    dev->dev_attrib.emulate_fua_write > 0 &&
 355                    (cmd->se_cmd_flags & SCF_FUA)) {
 356                        struct fd_dev *fd_dev = FD_DEV(dev);
 357                        loff_t start = cmd->t_task_lba *
 358                                dev->dev_attrib.block_size;
 359                        loff_t end = start + cmd->data_length;
 360
 361                        vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 362                }
 363        }
 364
 365        if (ret < 0)
 366                return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 367
 368        if (ret)
 369                target_complete_cmd(cmd, SAM_STAT_GOOD);
 370        return 0;
 371}
 372
 373enum {
 374        Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
 375};
 376
 377static match_table_t tokens = {
 378        {Opt_fd_dev_name, "fd_dev_name=%s"},
 379        {Opt_fd_dev_size, "fd_dev_size=%s"},
 380        {Opt_fd_buffered_io, "fd_buffered_io=%d"},
 381        {Opt_err, NULL}
 382};
 383
 384static ssize_t fd_set_configfs_dev_params(struct se_device *dev,
 385                const char *page, ssize_t count)
 386{
 387        struct fd_dev *fd_dev = FD_DEV(dev);
 388        char *orig, *ptr, *arg_p, *opts;
 389        substring_t args[MAX_OPT_ARGS];
 390        int ret = 0, arg, token;
 391
 392        opts = kstrdup(page, GFP_KERNEL);
 393        if (!opts)
 394                return -ENOMEM;
 395
 396        orig = opts;
 397
 398        while ((ptr = strsep(&opts, ",\n")) != NULL) {
 399                if (!*ptr)
 400                        continue;
 401
 402                token = match_token(ptr, tokens, args);
 403                switch (token) {
 404                case Opt_fd_dev_name:
 405                        if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
 406                                FD_MAX_DEV_NAME) == 0) {
 407                                ret = -EINVAL;
 408                                break;
 409                        }
 410                        pr_debug("FILEIO: Referencing Path: %s\n",
 411                                        fd_dev->fd_dev_name);
 412                        fd_dev->fbd_flags |= FBDF_HAS_PATH;
 413                        break;
 414                case Opt_fd_dev_size:
 415                        arg_p = match_strdup(&args[0]);
 416                        if (!arg_p) {
 417                                ret = -ENOMEM;
 418                                break;
 419                        }
 420                        ret = strict_strtoull(arg_p, 0, &fd_dev->fd_dev_size);
 421                        kfree(arg_p);
 422                        if (ret < 0) {
 423                                pr_err("strict_strtoull() failed for"
 424                                                " fd_dev_size=\n");
 425                                goto out;
 426                        }
 427                        pr_debug("FILEIO: Referencing Size: %llu"
 428                                        " bytes\n", fd_dev->fd_dev_size);
 429                        fd_dev->fbd_flags |= FBDF_HAS_SIZE;
 430                        break;
 431                case Opt_fd_buffered_io:
 432                        match_int(args, &arg);
 433                        if (arg != 1) {
 434                                pr_err("bogus fd_buffered_io=%d value\n", arg);
 435                                ret = -EINVAL;
 436                                goto out;
 437                        }
 438
 439                        pr_debug("FILEIO: Using buffered I/O"
 440                                " operations for struct fd_dev\n");
 441
 442                        fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
 443                        break;
 444                default:
 445                        break;
 446                }
 447        }
 448
 449out:
 450        kfree(orig);
 451        return (!ret) ? count : ret;
 452}
 453
 454static ssize_t fd_show_configfs_dev_params(struct se_device *dev, char *b)
 455{
 456        struct fd_dev *fd_dev = FD_DEV(dev);
 457        ssize_t bl = 0;
 458
 459        bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
 460        bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s\n",
 461                fd_dev->fd_dev_name, fd_dev->fd_dev_size,
 462                (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ?
 463                "Buffered-WCE" : "O_DSYNC");
 464        return bl;
 465}
 466
 467static sector_t fd_get_blocks(struct se_device *dev)
 468{
 469        struct fd_dev *fd_dev = FD_DEV(dev);
 470        struct file *f = fd_dev->fd_file;
 471        struct inode *i = f->f_mapping->host;
 472        unsigned long long dev_size;
 473        /*
 474         * When using a file that references an underlying struct block_device,
 475         * ensure dev_size is always based on the current inode size in order
 476         * to handle underlying block_device resize operations.
 477         */
 478        if (S_ISBLK(i->i_mode))
 479                dev_size = (i_size_read(i) - fd_dev->fd_block_size);
 480        else
 481                dev_size = fd_dev->fd_dev_size;
 482
 483        return div_u64(dev_size, dev->dev_attrib.block_size);
 484}
 485
 486static struct sbc_ops fd_sbc_ops = {
 487        .execute_rw             = fd_execute_rw,
 488        .execute_sync_cache     = fd_execute_sync_cache,
 489};
 490
 491static sense_reason_t
 492fd_parse_cdb(struct se_cmd *cmd)
 493{
 494        return sbc_parse_cdb(cmd, &fd_sbc_ops);
 495}
 496
 497static struct se_subsystem_api fileio_template = {
 498        .name                   = "fileio",
 499        .inquiry_prod           = "FILEIO",
 500        .inquiry_rev            = FD_VERSION,
 501        .owner                  = THIS_MODULE,
 502        .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 503        .attach_hba             = fd_attach_hba,
 504        .detach_hba             = fd_detach_hba,
 505        .alloc_device           = fd_alloc_device,
 506        .configure_device       = fd_configure_device,
 507        .free_device            = fd_free_device,
 508        .parse_cdb              = fd_parse_cdb,
 509        .set_configfs_dev_params = fd_set_configfs_dev_params,
 510        .show_configfs_dev_params = fd_show_configfs_dev_params,
 511        .get_device_type        = sbc_get_device_type,
 512        .get_blocks             = fd_get_blocks,
 513};
 514
 515static int __init fileio_module_init(void)
 516{
 517        return transport_subsystem_register(&fileio_template);
 518}
 519
 520static void fileio_module_exit(void)
 521{
 522        transport_subsystem_release(&fileio_template);
 523}
 524
 525MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
 526MODULE_AUTHOR("nab@Linux-iSCSI.org");
 527MODULE_LICENSE("GPL");
 528
 529module_init(fileio_module_init);
 530module_exit(fileio_module_exit);
 531
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