linux/fs/xfs/xfs_file.c
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   1/*
   2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   3 * All Rights Reserved.
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it would be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write the Free Software Foundation,
  16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18#include "xfs.h"
  19#include "xfs_fs.h"
  20#include "xfs_log.h"
  21#include "xfs_sb.h"
  22#include "xfs_ag.h"
  23#include "xfs_trans.h"
  24#include "xfs_mount.h"
  25#include "xfs_bmap_btree.h"
  26#include "xfs_alloc.h"
  27#include "xfs_dinode.h"
  28#include "xfs_inode.h"
  29#include "xfs_inode_item.h"
  30#include "xfs_bmap.h"
  31#include "xfs_error.h"
  32#include "xfs_vnodeops.h"
  33#include "xfs_da_btree.h"
  34#include "xfs_dir2_format.h"
  35#include "xfs_dir2_priv.h"
  36#include "xfs_ioctl.h"
  37#include "xfs_trace.h"
  38
  39#include <linux/aio.h>
  40#include <linux/dcache.h>
  41#include <linux/falloc.h>
  42#include <linux/pagevec.h>
  43
  44static const struct vm_operations_struct xfs_file_vm_ops;
  45
  46/*
  47 * Locking primitives for read and write IO paths to ensure we consistently use
  48 * and order the inode->i_mutex, ip->i_lock and ip->i_iolock.
  49 */
  50static inline void
  51xfs_rw_ilock(
  52        struct xfs_inode        *ip,
  53        int                     type)
  54{
  55        if (type & XFS_IOLOCK_EXCL)
  56                mutex_lock(&VFS_I(ip)->i_mutex);
  57        xfs_ilock(ip, type);
  58}
  59
  60static inline void
  61xfs_rw_iunlock(
  62        struct xfs_inode        *ip,
  63        int                     type)
  64{
  65        xfs_iunlock(ip, type);
  66        if (type & XFS_IOLOCK_EXCL)
  67                mutex_unlock(&VFS_I(ip)->i_mutex);
  68}
  69
  70static inline void
  71xfs_rw_ilock_demote(
  72        struct xfs_inode        *ip,
  73        int                     type)
  74{
  75        xfs_ilock_demote(ip, type);
  76        if (type & XFS_IOLOCK_EXCL)
  77                mutex_unlock(&VFS_I(ip)->i_mutex);
  78}
  79
  80/*
  81 *      xfs_iozero
  82 *
  83 *      xfs_iozero clears the specified range of buffer supplied,
  84 *      and marks all the affected blocks as valid and modified.  If
  85 *      an affected block is not allocated, it will be allocated.  If
  86 *      an affected block is not completely overwritten, and is not
  87 *      valid before the operation, it will be read from disk before
  88 *      being partially zeroed.
  89 */
  90int
  91xfs_iozero(
  92        struct xfs_inode        *ip,    /* inode                        */
  93        loff_t                  pos,    /* offset in file               */
  94        size_t                  count)  /* size of data to zero         */
  95{
  96        struct page             *page;
  97        struct address_space    *mapping;
  98        int                     status;
  99
 100        mapping = VFS_I(ip)->i_mapping;
 101        do {
 102                unsigned offset, bytes;
 103                void *fsdata;
 104
 105                offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
 106                bytes = PAGE_CACHE_SIZE - offset;
 107                if (bytes > count)
 108                        bytes = count;
 109
 110                status = pagecache_write_begin(NULL, mapping, pos, bytes,
 111                                        AOP_FLAG_UNINTERRUPTIBLE,
 112                                        &page, &fsdata);
 113                if (status)
 114                        break;
 115
 116                zero_user(page, offset, bytes);
 117
 118                status = pagecache_write_end(NULL, mapping, pos, bytes, bytes,
 119                                        page, fsdata);
 120                WARN_ON(status <= 0); /* can't return less than zero! */
 121                pos += bytes;
 122                count -= bytes;
 123                status = 0;
 124        } while (count);
 125
 126        return (-status);
 127}
 128
 129/*
 130 * Fsync operations on directories are much simpler than on regular files,
 131 * as there is no file data to flush, and thus also no need for explicit
 132 * cache flush operations, and there are no non-transaction metadata updates
 133 * on directories either.
 134 */
 135STATIC int
 136xfs_dir_fsync(
 137        struct file             *file,
 138        loff_t                  start,
 139        loff_t                  end,
 140        int                     datasync)
 141{
 142        struct xfs_inode        *ip = XFS_I(file->f_mapping->host);
 143        struct xfs_mount        *mp = ip->i_mount;
 144        xfs_lsn_t               lsn = 0;
 145
 146        trace_xfs_dir_fsync(ip);
 147
 148        xfs_ilock(ip, XFS_ILOCK_SHARED);
 149        if (xfs_ipincount(ip))
 150                lsn = ip->i_itemp->ili_last_lsn;
 151        xfs_iunlock(ip, XFS_ILOCK_SHARED);
 152
 153        if (!lsn)
 154                return 0;
 155        return _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
 156}
 157
 158STATIC int
 159xfs_file_fsync(
 160        struct file             *file,
 161        loff_t                  start,
 162        loff_t                  end,
 163        int                     datasync)
 164{
 165        struct inode            *inode = file->f_mapping->host;
 166        struct xfs_inode        *ip = XFS_I(inode);
 167        struct xfs_mount        *mp = ip->i_mount;
 168        int                     error = 0;
 169        int                     log_flushed = 0;
 170        xfs_lsn_t               lsn = 0;
 171
 172        trace_xfs_file_fsync(ip);
 173
 174        error = filemap_write_and_wait_range(inode->i_mapping, start, end);
 175        if (error)
 176                return error;
 177
 178        if (XFS_FORCED_SHUTDOWN(mp))
 179                return -XFS_ERROR(EIO);
 180
 181        xfs_iflags_clear(ip, XFS_ITRUNCATED);
 182
 183        if (mp->m_flags & XFS_MOUNT_BARRIER) {
 184                /*
 185                 * If we have an RT and/or log subvolume we need to make sure
 186                 * to flush the write cache the device used for file data
 187                 * first.  This is to ensure newly written file data make
 188                 * it to disk before logging the new inode size in case of
 189                 * an extending write.
 190                 */
 191                if (XFS_IS_REALTIME_INODE(ip))
 192                        xfs_blkdev_issue_flush(mp->m_rtdev_targp);
 193                else if (mp->m_logdev_targp != mp->m_ddev_targp)
 194                        xfs_blkdev_issue_flush(mp->m_ddev_targp);
 195        }
 196
 197        /*
 198         * All metadata updates are logged, which means that we just have
 199         * to flush the log up to the latest LSN that touched the inode.
 200         */
 201        xfs_ilock(ip, XFS_ILOCK_SHARED);
 202        if (xfs_ipincount(ip)) {
 203                if (!datasync ||
 204                    (ip->i_itemp->ili_fields & ~XFS_ILOG_TIMESTAMP))
 205                        lsn = ip->i_itemp->ili_last_lsn;
 206        }
 207        xfs_iunlock(ip, XFS_ILOCK_SHARED);
 208
 209        if (lsn)
 210                error = _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed);
 211
 212        /*
 213         * If we only have a single device, and the log force about was
 214         * a no-op we might have to flush the data device cache here.
 215         * This can only happen for fdatasync/O_DSYNC if we were overwriting
 216         * an already allocated file and thus do not have any metadata to
 217         * commit.
 218         */
 219        if ((mp->m_flags & XFS_MOUNT_BARRIER) &&
 220            mp->m_logdev_targp == mp->m_ddev_targp &&
 221            !XFS_IS_REALTIME_INODE(ip) &&
 222            !log_flushed)
 223                xfs_blkdev_issue_flush(mp->m_ddev_targp);
 224
 225        return -error;
 226}
 227
 228STATIC ssize_t
 229xfs_file_aio_read(
 230        struct kiocb            *iocb,
 231        const struct iovec      *iovp,
 232        unsigned long           nr_segs,
 233        loff_t                  pos)
 234{
 235        struct file             *file = iocb->ki_filp;
 236        struct inode            *inode = file->f_mapping->host;
 237        struct xfs_inode        *ip = XFS_I(inode);
 238        struct xfs_mount        *mp = ip->i_mount;
 239        size_t                  size = 0;
 240        ssize_t                 ret = 0;
 241        int                     ioflags = 0;
 242        xfs_fsize_t             n;
 243
 244        XFS_STATS_INC(xs_read_calls);
 245
 246        BUG_ON(iocb->ki_pos != pos);
 247
 248        if (unlikely(file->f_flags & O_DIRECT))
 249                ioflags |= IO_ISDIRECT;
 250        if (file->f_mode & FMODE_NOCMTIME)
 251                ioflags |= IO_INVIS;
 252
 253        ret = generic_segment_checks(iovp, &nr_segs, &size, VERIFY_WRITE);
 254        if (ret < 0)
 255                return ret;
 256
 257        if (unlikely(ioflags & IO_ISDIRECT)) {
 258                xfs_buftarg_t   *target =
 259                        XFS_IS_REALTIME_INODE(ip) ?
 260                                mp->m_rtdev_targp : mp->m_ddev_targp;
 261                if ((pos & target->bt_smask) || (size & target->bt_smask)) {
 262                        if (pos == i_size_read(inode))
 263                                return 0;
 264                        return -XFS_ERROR(EINVAL);
 265                }
 266        }
 267
 268        n = mp->m_super->s_maxbytes - pos;
 269        if (n <= 0 || size == 0)
 270                return 0;
 271
 272        if (n < size)
 273                size = n;
 274
 275        if (XFS_FORCED_SHUTDOWN(mp))
 276                return -EIO;
 277
 278        /*
 279         * Locking is a bit tricky here. If we take an exclusive lock
 280         * for direct IO, we effectively serialise all new concurrent
 281         * read IO to this file and block it behind IO that is currently in
 282         * progress because IO in progress holds the IO lock shared. We only
 283         * need to hold the lock exclusive to blow away the page cache, so
 284         * only take lock exclusively if the page cache needs invalidation.
 285         * This allows the normal direct IO case of no page cache pages to
 286         * proceeed concurrently without serialisation.
 287         */
 288        xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
 289        if ((ioflags & IO_ISDIRECT) && inode->i_mapping->nrpages) {
 290                xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
 291                xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
 292
 293                if (inode->i_mapping->nrpages) {
 294                        ret = -filemap_write_and_wait_range(
 295                                                        VFS_I(ip)->i_mapping,
 296                                                        pos, -1);
 297                        if (ret) {
 298                                xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);
 299                                return ret;
 300                        }
 301                        truncate_pagecache_range(VFS_I(ip), pos, -1);
 302                }
 303                xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
 304        }
 305
 306        trace_xfs_file_read(ip, size, pos, ioflags);
 307
 308        ret = generic_file_aio_read(iocb, iovp, nr_segs, pos);
 309        if (ret > 0)
 310                XFS_STATS_ADD(xs_read_bytes, ret);
 311
 312        xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
 313        return ret;
 314}
 315
 316STATIC ssize_t
 317xfs_file_splice_read(
 318        struct file             *infilp,
 319        loff_t                  *ppos,
 320        struct pipe_inode_info  *pipe,
 321        size_t                  count,
 322        unsigned int            flags)
 323{
 324        struct xfs_inode        *ip = XFS_I(infilp->f_mapping->host);
 325        int                     ioflags = 0;
 326        ssize_t                 ret;
 327
 328        XFS_STATS_INC(xs_read_calls);
 329
 330        if (infilp->f_mode & FMODE_NOCMTIME)
 331                ioflags |= IO_INVIS;
 332
 333        if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 334                return -EIO;
 335
 336        xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
 337
 338        trace_xfs_file_splice_read(ip, count, *ppos, ioflags);
 339
 340        ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
 341        if (ret > 0)
 342                XFS_STATS_ADD(xs_read_bytes, ret);
 343
 344        xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
 345        return ret;
 346}
 347
 348/*
 349 * xfs_file_splice_write() does not use xfs_rw_ilock() because
 350 * generic_file_splice_write() takes the i_mutex itself. This, in theory,
 351 * couuld cause lock inversions between the aio_write path and the splice path
 352 * if someone is doing concurrent splice(2) based writes and write(2) based
 353 * writes to the same inode. The only real way to fix this is to re-implement
 354 * the generic code here with correct locking orders.
 355 */
 356STATIC ssize_t
 357xfs_file_splice_write(
 358        struct pipe_inode_info  *pipe,
 359        struct file             *outfilp,
 360        loff_t                  *ppos,
 361        size_t                  count,
 362        unsigned int            flags)
 363{
 364        struct inode            *inode = outfilp->f_mapping->host;
 365        struct xfs_inode        *ip = XFS_I(inode);
 366        int                     ioflags = 0;
 367        ssize_t                 ret;
 368
 369        XFS_STATS_INC(xs_write_calls);
 370
 371        if (outfilp->f_mode & FMODE_NOCMTIME)
 372                ioflags |= IO_INVIS;
 373
 374        if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 375                return -EIO;
 376
 377        xfs_ilock(ip, XFS_IOLOCK_EXCL);
 378
 379        trace_xfs_file_splice_write(ip, count, *ppos, ioflags);
 380
 381        ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
 382        if (ret > 0)
 383                XFS_STATS_ADD(xs_write_bytes, ret);
 384
 385        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 386        return ret;
 387}
 388
 389/*
 390 * This routine is called to handle zeroing any space in the last block of the
 391 * file that is beyond the EOF.  We do this since the size is being increased
 392 * without writing anything to that block and we don't want to read the
 393 * garbage on the disk.
 394 */
 395STATIC int                              /* error (positive) */
 396xfs_zero_last_block(
 397        struct xfs_inode        *ip,
 398        xfs_fsize_t             offset,
 399        xfs_fsize_t             isize)
 400{
 401        struct xfs_mount        *mp = ip->i_mount;
 402        xfs_fileoff_t           last_fsb = XFS_B_TO_FSBT(mp, isize);
 403        int                     zero_offset = XFS_B_FSB_OFFSET(mp, isize);
 404        int                     zero_len;
 405        int                     nimaps = 1;
 406        int                     error = 0;
 407        struct xfs_bmbt_irec    imap;
 408
 409        xfs_ilock(ip, XFS_ILOCK_EXCL);
 410        error = xfs_bmapi_read(ip, last_fsb, 1, &imap, &nimaps, 0);
 411        xfs_iunlock(ip, XFS_ILOCK_EXCL);
 412        if (error)
 413                return error;
 414
 415        ASSERT(nimaps > 0);
 416
 417        /*
 418         * If the block underlying isize is just a hole, then there
 419         * is nothing to zero.
 420         */
 421        if (imap.br_startblock == HOLESTARTBLOCK)
 422                return 0;
 423
 424        zero_len = mp->m_sb.sb_blocksize - zero_offset;
 425        if (isize + zero_len > offset)
 426                zero_len = offset - isize;
 427        return xfs_iozero(ip, isize, zero_len);
 428}
 429
 430/*
 431 * Zero any on disk space between the current EOF and the new, larger EOF.
 432 *
 433 * This handles the normal case of zeroing the remainder of the last block in
 434 * the file and the unusual case of zeroing blocks out beyond the size of the
 435 * file.  This second case only happens with fixed size extents and when the
 436 * system crashes before the inode size was updated but after blocks were
 437 * allocated.
 438 *
 439 * Expects the iolock to be held exclusive, and will take the ilock internally.
 440 */
 441int                                     /* error (positive) */
 442xfs_zero_eof(
 443        struct xfs_inode        *ip,
 444        xfs_off_t               offset,         /* starting I/O offset */
 445        xfs_fsize_t             isize)          /* current inode size */
 446{
 447        struct xfs_mount        *mp = ip->i_mount;
 448        xfs_fileoff_t           start_zero_fsb;
 449        xfs_fileoff_t           end_zero_fsb;
 450        xfs_fileoff_t           zero_count_fsb;
 451        xfs_fileoff_t           last_fsb;
 452        xfs_fileoff_t           zero_off;
 453        xfs_fsize_t             zero_len;
 454        int                     nimaps;
 455        int                     error = 0;
 456        struct xfs_bmbt_irec    imap;
 457
 458        ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
 459        ASSERT(offset > isize);
 460
 461        /*
 462         * First handle zeroing the block on which isize resides.
 463         *
 464         * We only zero a part of that block so it is handled specially.
 465         */
 466        if (XFS_B_FSB_OFFSET(mp, isize) != 0) {
 467                error = xfs_zero_last_block(ip, offset, isize);
 468                if (error)
 469                        return error;
 470        }
 471
 472        /*
 473         * Calculate the range between the new size and the old where blocks
 474         * needing to be zeroed may exist.
 475         *
 476         * To get the block where the last byte in the file currently resides,
 477         * we need to subtract one from the size and truncate back to a block
 478         * boundary.  We subtract 1 in case the size is exactly on a block
 479         * boundary.
 480         */
 481        last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
 482        start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
 483        end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
 484        ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
 485        if (last_fsb == end_zero_fsb) {
 486                /*
 487                 * The size was only incremented on its last block.
 488                 * We took care of that above, so just return.
 489                 */
 490                return 0;
 491        }
 492
 493        ASSERT(start_zero_fsb <= end_zero_fsb);
 494        while (start_zero_fsb <= end_zero_fsb) {
 495                nimaps = 1;
 496                zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
 497
 498                xfs_ilock(ip, XFS_ILOCK_EXCL);
 499                error = xfs_bmapi_read(ip, start_zero_fsb, zero_count_fsb,
 500                                          &imap, &nimaps, 0);
 501                xfs_iunlock(ip, XFS_ILOCK_EXCL);
 502                if (error)
 503                        return error;
 504
 505                ASSERT(nimaps > 0);
 506
 507                if (imap.br_state == XFS_EXT_UNWRITTEN ||
 508                    imap.br_startblock == HOLESTARTBLOCK) {
 509                        start_zero_fsb = imap.br_startoff + imap.br_blockcount;
 510                        ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 511                        continue;
 512                }
 513
 514                /*
 515                 * There are blocks we need to zero.
 516                 */
 517                zero_off = XFS_FSB_TO_B(mp, start_zero_fsb);
 518                zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount);
 519
 520                if ((zero_off + zero_len) > offset)
 521                        zero_len = offset - zero_off;
 522
 523                error = xfs_iozero(ip, zero_off, zero_len);
 524                if (error)
 525                        return error;
 526
 527                start_zero_fsb = imap.br_startoff + imap.br_blockcount;
 528                ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 529        }
 530
 531        return 0;
 532}
 533
 534/*
 535 * Common pre-write limit and setup checks.
 536 *
 537 * Called with the iolocked held either shared and exclusive according to
 538 * @iolock, and returns with it held.  Might upgrade the iolock to exclusive
 539 * if called for a direct write beyond i_size.
 540 */
 541STATIC ssize_t
 542xfs_file_aio_write_checks(
 543        struct file             *file,
 544        loff_t                  *pos,
 545        size_t                  *count,
 546        int                     *iolock)
 547{
 548        struct inode            *inode = file->f_mapping->host;
 549        struct xfs_inode        *ip = XFS_I(inode);
 550        int                     error = 0;
 551
 552restart:
 553        error = generic_write_checks(file, pos, count, S_ISBLK(inode->i_mode));
 554        if (error)
 555                return error;
 556
 557        /*
 558         * If the offset is beyond the size of the file, we need to zero any
 559         * blocks that fall between the existing EOF and the start of this
 560         * write.  If zeroing is needed and we are currently holding the
 561         * iolock shared, we need to update it to exclusive which implies
 562         * having to redo all checks before.
 563         */
 564        if (*pos > i_size_read(inode)) {
 565                if (*iolock == XFS_IOLOCK_SHARED) {
 566                        xfs_rw_iunlock(ip, *iolock);
 567                        *iolock = XFS_IOLOCK_EXCL;
 568                        xfs_rw_ilock(ip, *iolock);
 569                        goto restart;
 570                }
 571                error = -xfs_zero_eof(ip, *pos, i_size_read(inode));
 572                if (error)
 573                        return error;
 574        }
 575
 576        /*
 577         * Updating the timestamps will grab the ilock again from
 578         * xfs_fs_dirty_inode, so we have to call it after dropping the
 579         * lock above.  Eventually we should look into a way to avoid
 580         * the pointless lock roundtrip.
 581         */
 582        if (likely(!(file->f_mode & FMODE_NOCMTIME))) {
 583                error = file_update_time(file);
 584                if (error)
 585                        return error;
 586        }
 587
 588        /*
 589         * If we're writing the file then make sure to clear the setuid and
 590         * setgid bits if the process is not being run by root.  This keeps
 591         * people from modifying setuid and setgid binaries.
 592         */
 593        return file_remove_suid(file);
 594}
 595
 596/*
 597 * xfs_file_dio_aio_write - handle direct IO writes
 598 *
 599 * Lock the inode appropriately to prepare for and issue a direct IO write.
 600 * By separating it from the buffered write path we remove all the tricky to
 601 * follow locking changes and looping.
 602 *
 603 * If there are cached pages or we're extending the file, we need IOLOCK_EXCL
 604 * until we're sure the bytes at the new EOF have been zeroed and/or the cached
 605 * pages are flushed out.
 606 *
 607 * In most cases the direct IO writes will be done holding IOLOCK_SHARED
 608 * allowing them to be done in parallel with reads and other direct IO writes.
 609 * However, if the IO is not aligned to filesystem blocks, the direct IO layer
 610 * needs to do sub-block zeroing and that requires serialisation against other
 611 * direct IOs to the same block. In this case we need to serialise the
 612 * submission of the unaligned IOs so that we don't get racing block zeroing in
 613 * the dio layer.  To avoid the problem with aio, we also need to wait for
 614 * outstanding IOs to complete so that unwritten extent conversion is completed
 615 * before we try to map the overlapping block. This is currently implemented by
 616 * hitting it with a big hammer (i.e. inode_dio_wait()).
 617 *
 618 * Returns with locks held indicated by @iolock and errors indicated by
 619 * negative return values.
 620 */
 621STATIC ssize_t
 622xfs_file_dio_aio_write(
 623        struct kiocb            *iocb,
 624        const struct iovec      *iovp,
 625        unsigned long           nr_segs,
 626        loff_t                  pos,
 627        size_t                  ocount)
 628{
 629        struct file             *file = iocb->ki_filp;
 630        struct address_space    *mapping = file->f_mapping;
 631        struct inode            *inode = mapping->host;
 632        struct xfs_inode        *ip = XFS_I(inode);
 633        struct xfs_mount        *mp = ip->i_mount;
 634        ssize_t                 ret = 0;
 635        size_t                  count = ocount;
 636        int                     unaligned_io = 0;
 637        int                     iolock;
 638        struct xfs_buftarg      *target = XFS_IS_REALTIME_INODE(ip) ?
 639                                        mp->m_rtdev_targp : mp->m_ddev_targp;
 640
 641        if ((pos & target->bt_smask) || (count & target->bt_smask))
 642                return -XFS_ERROR(EINVAL);
 643
 644        if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
 645                unaligned_io = 1;
 646
 647        /*
 648         * We don't need to take an exclusive lock unless there page cache needs
 649         * to be invalidated or unaligned IO is being executed. We don't need to
 650         * consider the EOF extension case here because
 651         * xfs_file_aio_write_checks() will relock the inode as necessary for
 652         * EOF zeroing cases and fill out the new inode size as appropriate.
 653         */
 654        if (unaligned_io || mapping->nrpages)
 655                iolock = XFS_IOLOCK_EXCL;
 656        else
 657                iolock = XFS_IOLOCK_SHARED;
 658        xfs_rw_ilock(ip, iolock);
 659
 660        /*
 661         * Recheck if there are cached pages that need invalidate after we got
 662         * the iolock to protect against other threads adding new pages while
 663         * we were waiting for the iolock.
 664         */
 665        if (mapping->nrpages && iolock == XFS_IOLOCK_SHARED) {
 666                xfs_rw_iunlock(ip, iolock);
 667                iolock = XFS_IOLOCK_EXCL;
 668                xfs_rw_ilock(ip, iolock);
 669        }
 670
 671        ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
 672        if (ret)
 673                goto out;
 674
 675        if (mapping->nrpages) {
 676                ret = -filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
 677                                                    pos, -1);
 678                if (ret)
 679                        goto out;
 680                truncate_pagecache_range(VFS_I(ip), pos, -1);
 681        }
 682
 683        /*
 684         * If we are doing unaligned IO, wait for all other IO to drain,
 685         * otherwise demote the lock if we had to flush cached pages
 686         */
 687        if (unaligned_io)
 688                inode_dio_wait(inode);
 689        else if (iolock == XFS_IOLOCK_EXCL) {
 690                xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
 691                iolock = XFS_IOLOCK_SHARED;
 692        }
 693
 694        trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
 695        ret = generic_file_direct_write(iocb, iovp,
 696                        &nr_segs, pos, &iocb->ki_pos, count, ocount);
 697
 698out:
 699        xfs_rw_iunlock(ip, iolock);
 700
 701        /* No fallback to buffered IO on errors for XFS. */
 702        ASSERT(ret < 0 || ret == count);
 703        return ret;
 704}
 705
 706STATIC ssize_t
 707xfs_file_buffered_aio_write(
 708        struct kiocb            *iocb,
 709        const struct iovec      *iovp,
 710        unsigned long           nr_segs,
 711        loff_t                  pos,
 712        size_t                  ocount)
 713{
 714        struct file             *file = iocb->ki_filp;
 715        struct address_space    *mapping = file->f_mapping;
 716        struct inode            *inode = mapping->host;
 717        struct xfs_inode        *ip = XFS_I(inode);
 718        ssize_t                 ret;
 719        int                     enospc = 0;
 720        int                     iolock = XFS_IOLOCK_EXCL;
 721        size_t                  count = ocount;
 722
 723        xfs_rw_ilock(ip, iolock);
 724
 725        ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
 726        if (ret)
 727                goto out;
 728
 729        /* We can write back this queue in page reclaim */
 730        current->backing_dev_info = mapping->backing_dev_info;
 731
 732write_retry:
 733        trace_xfs_file_buffered_write(ip, count, iocb->ki_pos, 0);
 734        ret = generic_file_buffered_write(iocb, iovp, nr_segs,
 735                        pos, &iocb->ki_pos, count, 0);
 736
 737        /*
 738         * If we just got an ENOSPC, try to write back all dirty inodes to
 739         * convert delalloc space to free up some of the excess reserved
 740         * metadata space.
 741         */
 742        if (ret == -ENOSPC && !enospc) {
 743                enospc = 1;
 744                xfs_flush_inodes(ip->i_mount);
 745                goto write_retry;
 746        }
 747
 748        current->backing_dev_info = NULL;
 749out:
 750        xfs_rw_iunlock(ip, iolock);
 751        return ret;
 752}
 753
 754STATIC ssize_t
 755xfs_file_aio_write(
 756        struct kiocb            *iocb,
 757        const struct iovec      *iovp,
 758        unsigned long           nr_segs,
 759        loff_t                  pos)
 760{
 761        struct file             *file = iocb->ki_filp;
 762        struct address_space    *mapping = file->f_mapping;
 763        struct inode            *inode = mapping->host;
 764        struct xfs_inode        *ip = XFS_I(inode);
 765        ssize_t                 ret;
 766        size_t                  ocount = 0;
 767
 768        XFS_STATS_INC(xs_write_calls);
 769
 770        BUG_ON(iocb->ki_pos != pos);
 771
 772        ret = generic_segment_checks(iovp, &nr_segs, &ocount, VERIFY_READ);
 773        if (ret)
 774                return ret;
 775
 776        if (ocount == 0)
 777                return 0;
 778
 779        if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
 780                ret = -EIO;
 781                goto out;
 782        }
 783
 784        if (unlikely(file->f_flags & O_DIRECT))
 785                ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos, ocount);
 786        else
 787                ret = xfs_file_buffered_aio_write(iocb, iovp, nr_segs, pos,
 788                                                  ocount);
 789
 790        if (ret > 0) {
 791                ssize_t err;
 792
 793                XFS_STATS_ADD(xs_write_bytes, ret);
 794
 795                /* Handle various SYNC-type writes */
 796                err = generic_write_sync(file, pos, ret);
 797                if (err < 0)
 798                        ret = err;
 799        }
 800
 801out:
 802        return ret;
 803}
 804
 805STATIC long
 806xfs_file_fallocate(
 807        struct file     *file,
 808        int             mode,
 809        loff_t          offset,
 810        loff_t          len)
 811{
 812        struct inode    *inode = file_inode(file);
 813        long            error;
 814        loff_t          new_size = 0;
 815        xfs_flock64_t   bf;
 816        xfs_inode_t     *ip = XFS_I(inode);
 817        int             cmd = XFS_IOC_RESVSP;
 818        int             attr_flags = XFS_ATTR_NOLOCK;
 819
 820        if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 821                return -EOPNOTSUPP;
 822
 823        bf.l_whence = 0;
 824        bf.l_start = offset;
 825        bf.l_len = len;
 826
 827        xfs_ilock(ip, XFS_IOLOCK_EXCL);
 828
 829        if (mode & FALLOC_FL_PUNCH_HOLE)
 830                cmd = XFS_IOC_UNRESVSP;
 831
 832        /* check the new inode size is valid before allocating */
 833        if (!(mode & FALLOC_FL_KEEP_SIZE) &&
 834            offset + len > i_size_read(inode)) {
 835                new_size = offset + len;
 836                error = inode_newsize_ok(inode, new_size);
 837                if (error)
 838                        goto out_unlock;
 839        }
 840
 841        if (file->f_flags & O_DSYNC)
 842                attr_flags |= XFS_ATTR_SYNC;
 843
 844        error = -xfs_change_file_space(ip, cmd, &bf, 0, attr_flags);
 845        if (error)
 846                goto out_unlock;
 847
 848        /* Change file size if needed */
 849        if (new_size) {
 850                struct iattr iattr;
 851
 852                iattr.ia_valid = ATTR_SIZE;
 853                iattr.ia_size = new_size;
 854                error = -xfs_setattr_size(ip, &iattr, XFS_ATTR_NOLOCK);
 855        }
 856
 857out_unlock:
 858        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 859        return error;
 860}
 861
 862
 863STATIC int
 864xfs_file_open(
 865        struct inode    *inode,
 866        struct file     *file)
 867{
 868        if (!(file->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
 869                return -EFBIG;
 870        if (XFS_FORCED_SHUTDOWN(XFS_M(inode->i_sb)))
 871                return -EIO;
 872        return 0;
 873}
 874
 875STATIC int
 876xfs_dir_open(
 877        struct inode    *inode,
 878        struct file     *file)
 879{
 880        struct xfs_inode *ip = XFS_I(inode);
 881        int             mode;
 882        int             error;
 883
 884        error = xfs_file_open(inode, file);
 885        if (error)
 886                return error;
 887
 888        /*
 889         * If there are any blocks, read-ahead block 0 as we're almost
 890         * certain to have the next operation be a read there.
 891         */
 892        mode = xfs_ilock_map_shared(ip);
 893        if (ip->i_d.di_nextents > 0)
 894                xfs_dir3_data_readahead(NULL, ip, 0, -1);
 895        xfs_iunlock(ip, mode);
 896        return 0;
 897}
 898
 899STATIC int
 900xfs_file_release(
 901        struct inode    *inode,
 902        struct file     *filp)
 903{
 904        return -xfs_release(XFS_I(inode));
 905}
 906
 907STATIC int
 908xfs_file_readdir(
 909        struct file     *file,
 910        struct dir_context *ctx)
 911{
 912        struct inode    *inode = file_inode(file);
 913        xfs_inode_t     *ip = XFS_I(inode);
 914        int             error;
 915        size_t          bufsize;
 916
 917        /*
 918         * The Linux API doesn't pass down the total size of the buffer
 919         * we read into down to the filesystem.  With the filldir concept
 920         * it's not needed for correct information, but the XFS dir2 leaf
 921         * code wants an estimate of the buffer size to calculate it's
 922         * readahead window and size the buffers used for mapping to
 923         * physical blocks.
 924         *
 925         * Try to give it an estimate that's good enough, maybe at some
 926         * point we can change the ->readdir prototype to include the
 927         * buffer size.  For now we use the current glibc buffer size.
 928         */
 929        bufsize = (size_t)min_t(loff_t, 32768, ip->i_d.di_size);
 930
 931        error = xfs_readdir(ip, ctx, bufsize);
 932        if (error)
 933                return -error;
 934        return 0;
 935}
 936
 937STATIC int
 938xfs_file_mmap(
 939        struct file     *filp,
 940        struct vm_area_struct *vma)
 941{
 942        vma->vm_ops = &xfs_file_vm_ops;
 943
 944        file_accessed(filp);
 945        return 0;
 946}
 947
 948/*
 949 * mmap()d file has taken write protection fault and is being made
 950 * writable. We can set the page state up correctly for a writable
 951 * page, which means we can do correct delalloc accounting (ENOSPC
 952 * checking!) and unwritten extent mapping.
 953 */
 954STATIC int
 955xfs_vm_page_mkwrite(
 956        struct vm_area_struct   *vma,
 957        struct vm_fault         *vmf)
 958{
 959        return block_page_mkwrite(vma, vmf, xfs_get_blocks);
 960}
 961
 962/*
 963 * This type is designed to indicate the type of offset we would like
 964 * to search from page cache for either xfs_seek_data() or xfs_seek_hole().
 965 */
 966enum {
 967        HOLE_OFF = 0,
 968        DATA_OFF,
 969};
 970
 971/*
 972 * Lookup the desired type of offset from the given page.
 973 *
 974 * On success, return true and the offset argument will point to the
 975 * start of the region that was found.  Otherwise this function will
 976 * return false and keep the offset argument unchanged.
 977 */
 978STATIC bool
 979xfs_lookup_buffer_offset(
 980        struct page             *page,
 981        loff_t                  *offset,
 982        unsigned int            type)
 983{
 984        loff_t                  lastoff = page_offset(page);
 985        bool                    found = false;
 986        struct buffer_head      *bh, *head;
 987
 988        bh = head = page_buffers(page);
 989        do {
 990                /*
 991                 * Unwritten extents that have data in the page
 992                 * cache covering them can be identified by the
 993                 * BH_Unwritten state flag.  Pages with multiple
 994                 * buffers might have a mix of holes, data and
 995                 * unwritten extents - any buffer with valid
 996                 * data in it should have BH_Uptodate flag set
 997                 * on it.
 998                 */
 999                if (buffer_unwritten(bh) ||
1000                    buffer_uptodate(bh)) {
1001                        if (type == DATA_OFF)
1002                                found = true;
1003                } else {
1004                        if (type == HOLE_OFF)
1005                                found = true;
1006                }
1007
1008                if (found) {
1009                        *offset = lastoff;
1010                        break;
1011                }
1012                lastoff += bh->b_size;
1013        } while ((bh = bh->b_this_page) != head);
1014
1015        return found;
1016}
1017
1018/*
1019 * This routine is called to find out and return a data or hole offset
1020 * from the page cache for unwritten extents according to the desired
1021 * type for xfs_seek_data() or xfs_seek_hole().
1022 *
1023 * The argument offset is used to tell where we start to search from the
1024 * page cache.  Map is used to figure out the end points of the range to
1025 * lookup pages.
1026 *
1027 * Return true if the desired type of offset was found, and the argument
1028 * offset is filled with that address.  Otherwise, return false and keep
1029 * offset unchanged.
1030 */
1031STATIC bool
1032xfs_find_get_desired_pgoff(
1033        struct inode            *inode,
1034        struct xfs_bmbt_irec    *map,
1035        unsigned int            type,
1036        loff_t                  *offset)
1037{
1038        struct xfs_inode        *ip = XFS_I(inode);
1039        struct xfs_mount        *mp = ip->i_mount;
1040        struct pagevec          pvec;
1041        pgoff_t                 index;
1042        pgoff_t                 end;
1043        loff_t                  endoff;
1044        loff_t                  startoff = *offset;
1045        loff_t                  lastoff = startoff;
1046        bool                    found = false;
1047
1048        pagevec_init(&pvec, 0);
1049
1050        index = startoff >> PAGE_CACHE_SHIFT;
1051        endoff = XFS_FSB_TO_B(mp, map->br_startoff + map->br_blockcount);
1052        end = endoff >> PAGE_CACHE_SHIFT;
1053        do {
1054                int             want;
1055                unsigned        nr_pages;
1056                unsigned int    i;
1057
1058                want = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
1059                nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
1060                                          want);
1061                /*
1062                 * No page mapped into given range.  If we are searching holes
1063                 * and if this is the first time we got into the loop, it means
1064                 * that the given offset is landed in a hole, return it.
1065                 *
1066                 * If we have already stepped through some block buffers to find
1067                 * holes but they all contains data.  In this case, the last
1068                 * offset is already updated and pointed to the end of the last
1069                 * mapped page, if it does not reach the endpoint to search,
1070                 * that means there should be a hole between them.
1071                 */
1072                if (nr_pages == 0) {
1073                        /* Data search found nothing */
1074                        if (type == DATA_OFF)
1075                                break;
1076
1077                        ASSERT(type == HOLE_OFF);
1078                        if (lastoff == startoff || lastoff < endoff) {
1079                                found = true;
1080                                *offset = lastoff;
1081                        }
1082                        break;
1083                }
1084
1085                /*
1086                 * At lease we found one page.  If this is the first time we
1087                 * step into the loop, and if the first page index offset is
1088                 * greater than the given search offset, a hole was found.
1089                 */
1090                if (type == HOLE_OFF && lastoff == startoff &&
1091                    lastoff < page_offset(pvec.pages[0])) {
1092                        found = true;
1093                        break;
1094                }
1095
1096                for (i = 0; i < nr_pages; i++) {
1097                        struct page     *page = pvec.pages[i];
1098                        loff_t          b_offset;
1099
1100                        /*
1101                         * At this point, the page may be truncated or
1102                         * invalidated (changing page->mapping to NULL),
1103                         * or even swizzled back from swapper_space to tmpfs
1104                         * file mapping. However, page->index will not change
1105                         * because we have a reference on the page.
1106                         *
1107                         * Searching done if the page index is out of range.
1108                         * If the current offset is not reaches the end of
1109                         * the specified search range, there should be a hole
1110                         * between them.
1111                         */
1112                        if (page->index > end) {
1113                                if (type == HOLE_OFF && lastoff < endoff) {
1114                                        *offset = lastoff;
1115                                        found = true;
1116                                }
1117                                goto out;
1118                        }
1119
1120                        lock_page(page);
1121                        /*
1122                         * Page truncated or invalidated(page->mapping == NULL).
1123                         * We can freely skip it and proceed to check the next
1124                         * page.
1125                         */
1126                        if (unlikely(page->mapping != inode->i_mapping)) {
1127                                unlock_page(page);
1128                                continue;
1129                        }
1130
1131                        if (!page_has_buffers(page)) {
1132                                unlock_page(page);
1133                                continue;
1134                        }
1135
1136                        found = xfs_lookup_buffer_offset(page, &b_offset, type);
1137                        if (found) {
1138                                /*
1139                                 * The found offset may be less than the start
1140                                 * point to search if this is the first time to
1141                                 * come here.
1142                                 */
1143                                *offset = max_t(loff_t, startoff, b_offset);
1144                                unlock_page(page);
1145                                goto out;
1146                        }
1147
1148                        /*
1149                         * We either searching data but nothing was found, or
1150                         * searching hole but found a data buffer.  In either
1151                         * case, probably the next page contains the desired
1152                         * things, update the last offset to it so.
1153                         */
1154                        lastoff = page_offset(page) + PAGE_SIZE;
1155                        unlock_page(page);
1156                }
1157
1158                /*
1159                 * The number of returned pages less than our desired, search
1160                 * done.  In this case, nothing was found for searching data,
1161                 * but we found a hole behind the last offset.
1162                 */
1163                if (nr_pages < want) {
1164                        if (type == HOLE_OFF) {
1165                                *offset = lastoff;
1166                                found = true;
1167                        }
1168                        break;
1169                }
1170
1171                index = pvec.pages[i - 1]->index + 1;
1172                pagevec_release(&pvec);
1173        } while (index <= end);
1174
1175out:
1176        pagevec_release(&pvec);
1177        return found;
1178}
1179
1180STATIC loff_t
1181xfs_seek_data(
1182        struct file             *file,
1183        loff_t                  start)
1184{
1185        struct inode            *inode = file->f_mapping->host;
1186        struct xfs_inode        *ip = XFS_I(inode);
1187        struct xfs_mount        *mp = ip->i_mount;
1188        loff_t                  uninitialized_var(offset);
1189        xfs_fsize_t             isize;
1190        xfs_fileoff_t           fsbno;
1191        xfs_filblks_t           end;
1192        uint                    lock;
1193        int                     error;
1194
1195        lock = xfs_ilock_map_shared(ip);
1196
1197        isize = i_size_read(inode);
1198        if (start >= isize) {
1199                error = ENXIO;
1200                goto out_unlock;
1201        }
1202
1203        /*
1204         * Try to read extents from the first block indicated
1205         * by fsbno to the end block of the file.
1206         */
1207        fsbno = XFS_B_TO_FSBT(mp, start);
1208        end = XFS_B_TO_FSB(mp, isize);
1209        for (;;) {
1210                struct xfs_bmbt_irec    map[2];
1211                int                     nmap = 2;
1212                unsigned int            i;
1213
1214                error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap,
1215                                       XFS_BMAPI_ENTIRE);
1216                if (error)
1217                        goto out_unlock;
1218
1219                /* No extents at given offset, must be beyond EOF */
1220                if (nmap == 0) {
1221                        error = ENXIO;
1222                        goto out_unlock;
1223                }
1224
1225                for (i = 0; i < nmap; i++) {
1226                        offset = max_t(loff_t, start,
1227                                       XFS_FSB_TO_B(mp, map[i].br_startoff));
1228
1229                        /* Landed in a data extent */
1230                        if (map[i].br_startblock == DELAYSTARTBLOCK ||
1231                            (map[i].br_state == XFS_EXT_NORM &&
1232                             !isnullstartblock(map[i].br_startblock)))
1233                                goto out;
1234
1235                        /*
1236                         * Landed in an unwritten extent, try to search data
1237                         * from page cache.
1238                         */
1239                        if (map[i].br_state == XFS_EXT_UNWRITTEN) {
1240                                if (xfs_find_get_desired_pgoff(inode, &map[i],
1241                                                        DATA_OFF, &offset))
1242                                        goto out;
1243                        }
1244                }
1245
1246                /*
1247                 * map[0] is hole or its an unwritten extent but
1248                 * without data in page cache.  Probably means that
1249                 * we are reading after EOF if nothing in map[1].
1250                 */
1251                if (nmap == 1) {
1252                        error = ENXIO;
1253                        goto out_unlock;
1254                }
1255
1256                ASSERT(i > 1);
1257
1258                /*
1259                 * Nothing was found, proceed to the next round of search
1260                 * if reading offset not beyond or hit EOF.
1261                 */
1262                fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
1263                start = XFS_FSB_TO_B(mp, fsbno);
1264                if (start >= isize) {
1265                        error = ENXIO;
1266                        goto out_unlock;
1267                }
1268        }
1269
1270out:
1271        offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
1272
1273out_unlock:
1274        xfs_iunlock_map_shared(ip, lock);
1275
1276        if (error)
1277                return -error;
1278        return offset;
1279}
1280
1281STATIC loff_t
1282xfs_seek_hole(
1283        struct file             *file,
1284        loff_t                  start)
1285{
1286        struct inode            *inode = file->f_mapping->host;
1287        struct xfs_inode        *ip = XFS_I(inode);
1288        struct xfs_mount        *mp = ip->i_mount;
1289        loff_t                  uninitialized_var(offset);
1290        xfs_fsize_t             isize;
1291        xfs_fileoff_t           fsbno;
1292        xfs_filblks_t           end;
1293        uint                    lock;
1294        int                     error;
1295
1296        if (XFS_FORCED_SHUTDOWN(mp))
1297                return -XFS_ERROR(EIO);
1298
1299        lock = xfs_ilock_map_shared(ip);
1300
1301        isize = i_size_read(inode);
1302        if (start >= isize) {
1303                error = ENXIO;
1304                goto out_unlock;
1305        }
1306
1307        fsbno = XFS_B_TO_FSBT(mp, start);
1308        end = XFS_B_TO_FSB(mp, isize);
1309
1310        for (;;) {
1311                struct xfs_bmbt_irec    map[2];
1312                int                     nmap = 2;
1313                unsigned int            i;
1314
1315                error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap,
1316                                       XFS_BMAPI_ENTIRE);
1317                if (error)
1318                        goto out_unlock;
1319
1320                /* No extents at given offset, must be beyond EOF */
1321                if (nmap == 0) {
1322                        error = ENXIO;
1323                        goto out_unlock;
1324                }
1325
1326                for (i = 0; i < nmap; i++) {
1327                        offset = max_t(loff_t, start,
1328                                       XFS_FSB_TO_B(mp, map[i].br_startoff));
1329
1330                        /* Landed in a hole */
1331                        if (map[i].br_startblock == HOLESTARTBLOCK)
1332                                goto out;
1333
1334                        /*
1335                         * Landed in an unwritten extent, try to search hole
1336                         * from page cache.
1337                         */
1338                        if (map[i].br_state == XFS_EXT_UNWRITTEN) {
1339                                if (xfs_find_get_desired_pgoff(inode, &map[i],
1340                                                        HOLE_OFF, &offset))
1341                                        goto out;
1342                        }
1343                }
1344
1345                /*
1346                 * map[0] contains data or its unwritten but contains
1347                 * data in page cache, probably means that we are
1348                 * reading after EOF.  We should fix offset to point
1349                 * to the end of the file(i.e., there is an implicit
1350                 * hole at the end of any file).
1351                 */
1352                if (nmap == 1) {
1353                        offset = isize;
1354                        break;
1355                }
1356
1357                ASSERT(i > 1);
1358
1359                /*
1360                 * Both mappings contains data, proceed to the next round of
1361                 * search if the current reading offset not beyond or hit EOF.
1362                 */
1363                fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
1364                start = XFS_FSB_TO_B(mp, fsbno);
1365                if (start >= isize) {
1366                        offset = isize;
1367                        break;
1368                }
1369        }
1370
1371out:
1372        /*
1373         * At this point, we must have found a hole.  However, the returned
1374         * offset may be bigger than the file size as it may be aligned to
1375         * page boundary for unwritten extents, we need to deal with this
1376         * situation in particular.
1377         */
1378        offset = min_t(loff_t, offset, isize);
1379        offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
1380
1381out_unlock:
1382        xfs_iunlock_map_shared(ip, lock);
1383
1384        if (error)
1385                return -error;
1386        return offset;
1387}
1388
1389STATIC loff_t
1390xfs_file_llseek(
1391        struct file     *file,
1392        loff_t          offset,
1393        int             origin)
1394{
1395        switch (origin) {
1396        case SEEK_END:
1397        case SEEK_CUR:
1398        case SEEK_SET:
1399                return generic_file_llseek(file, offset, origin);
1400        case SEEK_DATA:
1401                return xfs_seek_data(file, offset);
1402        case SEEK_HOLE:
1403                return xfs_seek_hole(file, offset);
1404        default:
1405                return -EINVAL;
1406        }
1407}
1408
1409const struct file_operations xfs_file_operations = {
1410        .llseek         = xfs_file_llseek,
1411        .read           = do_sync_read,
1412        .write          = do_sync_write,
1413        .aio_read       = xfs_file_aio_read,
1414        .aio_write      = xfs_file_aio_write,
1415        .splice_read    = xfs_file_splice_read,
1416        .splice_write   = xfs_file_splice_write,
1417        .unlocked_ioctl = xfs_file_ioctl,
1418#ifdef CONFIG_COMPAT
1419        .compat_ioctl   = xfs_file_compat_ioctl,
1420#endif
1421        .mmap           = xfs_file_mmap,
1422        .open           = xfs_file_open,
1423        .release        = xfs_file_release,
1424        .fsync          = xfs_file_fsync,
1425        .fallocate      = xfs_file_fallocate,
1426};
1427
1428const struct file_operations xfs_dir_file_operations = {
1429        .open           = xfs_dir_open,
1430        .read           = generic_read_dir,
1431        .iterate        = xfs_file_readdir,
1432        .llseek         = generic_file_llseek,
1433        .unlocked_ioctl = xfs_file_ioctl,
1434#ifdef CONFIG_COMPAT
1435        .compat_ioctl   = xfs_file_compat_ioctl,
1436#endif
1437        .fsync          = xfs_dir_fsync,
1438};
1439
1440static const struct vm_operations_struct xfs_file_vm_ops = {
1441        .fault          = filemap_fault,
1442        .page_mkwrite   = xfs_vm_page_mkwrite,
1443        .remap_pages    = generic_file_remap_pages,
1444};
1445
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