fs/xfs/linux-2.6/xfs_lrw.c

   1 /*
   2  * Copyright (c) 2000-2003,2005 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_bit.h"
  21 #include "xfs_log.h"
  22 #include "xfs_inum.h"
  23 #include "xfs_trans.h"
  24 #include "xfs_sb.h"
  25 #include "xfs_ag.h"
  26 #include "xfs_dir.h"
  27 #include "xfs_dir2.h"
  28 #include "xfs_alloc.h"
  29 #include "xfs_dmapi.h"
  30 #include "xfs_quota.h"
  31 #include "xfs_mount.h"
  32 #include "xfs_bmap_btree.h"
  33 #include "xfs_alloc_btree.h"
  34 #include "xfs_ialloc_btree.h"
  35 #include "xfs_dir_sf.h"
  36 #include "xfs_dir2_sf.h"
  37 #include "xfs_attr_sf.h"
  38 #include "xfs_dinode.h"
  39 #include "xfs_inode.h"
  40 #include "xfs_bmap.h"
  41 #include "xfs_btree.h"
  42 #include "xfs_ialloc.h"
  43 #include "xfs_rtalloc.h"
  44 #include "xfs_error.h"
  45 #include "xfs_itable.h"
  46 #include "xfs_rw.h"
  47 #include "xfs_acl.h"
  48 #include "xfs_cap.h"
  49 #include "xfs_mac.h"
  50 #include "xfs_attr.h"
  51 #include "xfs_inode_item.h"
  52 #include "xfs_buf_item.h"
  53 #include "xfs_utils.h"
  54 #include "xfs_iomap.h"
  55
  56 #include <linux/capability.h>
  57 #include <linux/writeback.h>
  58
  59
  60 #if defined(XFS_RW_TRACE)
  61 void
  62 xfs_rw_enter_trace(
  63         int                     tag,
  64         xfs_iocore_t            *io,
  65         void                    *data,
  66         size_t                  segs,
  67         loff_t                  offset,
  68         int                     ioflags)
  69 {
  70         xfs_inode_t     *ip = XFS_IO_INODE(io);
  71
  72         if (ip->i_rwtrace == NULL)
  73                 return;
  74         ktrace_enter(ip->i_rwtrace,
  75                 (void *)(unsigned long)tag,
  76                 (void *)ip,
  77                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
  78                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
  79                 (void *)data,
  80                 (void *)((unsigned long)segs),
  81                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
  82                 (void *)((unsigned long)(offset & 0xffffffff)),
  83                 (void *)((unsigned long)ioflags),
  84                 (void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
  85                 (void *)((unsigned long)(io->io_new_size & 0xffffffff)),
  86                 (void *)((unsigned long)current_pid()),
  87                 (void *)NULL,
  88                 (void *)NULL,
  89                 (void *)NULL,
  90                 (void *)NULL);
  91 }
  92
  93 void
  94 xfs_inval_cached_trace(
  95         xfs_iocore_t    *io,
  96         xfs_off_t       offset,
  97         xfs_off_t       len,
  98         xfs_off_t       first,
  99         xfs_off_t       last)
 100 {
 101         xfs_inode_t     *ip = XFS_IO_INODE(io);
 102
 103         if (ip->i_rwtrace == NULL)
 104                 return;
 105         ktrace_enter(ip->i_rwtrace,
 106                 (void *)(__psint_t)XFS_INVAL_CACHED,
 107                 (void *)ip,
 108                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
 109                 (void *)((unsigned long)(offset & 0xffffffff)),
 110                 (void *)((unsigned long)((len >> 32) & 0xffffffff)),
 111                 (void *)((unsigned long)(len & 0xffffffff)),
 112                 (void *)((unsigned long)((first >> 32) & 0xffffffff)),
 113                 (void *)((unsigned long)(first & 0xffffffff)),
 114                 (void *)((unsigned long)((last >> 32) & 0xffffffff)),
 115                 (void *)((unsigned long)(last & 0xffffffff)),
 116                 (void *)((unsigned long)current_pid()),
 117                 (void *)NULL,
 118                 (void *)NULL,
 119                 (void *)NULL,
 120                 (void *)NULL,
 121                 (void *)NULL);
 122 }
 123 #endif
 124
 125 /*
 126  *      xfs_iozero
 127  *
 128  *      xfs_iozero clears the specified range of buffer supplied,
 129  *      and marks all the affected blocks as valid and modified.  If
 130  *      an affected block is not allocated, it will be allocated.  If
 131  *      an affected block is not completely overwritten, and is not
 132  *      valid before the operation, it will be read from disk before
 133  *      being partially zeroed.
 134  */
 135 STATIC int
 136 xfs_iozero(
 137         struct inode            *ip,    /* inode                        */
 138         loff_t                  pos,    /* offset in file               */
 139         size_t                  count,  /* size of data to zero         */
 140         loff_t                  end_size)       /* max file size to set */
 141 {
 142         unsigned                bytes;
 143         struct page             *page;
 144         struct address_space    *mapping;
 145         char                    *kaddr;
 146         int                     status;
 147
 148         mapping = ip->i_mapping;
 149         do {
 150                 unsigned long index, offset;
 151
 152                 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
 153                 index = pos >> PAGE_CACHE_SHIFT;
 154                 bytes = PAGE_CACHE_SIZE - offset;
 155                 if (bytes > count)
 156                         bytes = count;
 157
 158                 status = -ENOMEM;
 159                 page = grab_cache_page(mapping, index);
 160                 if (!page)
 161                         break;
 162
 163                 kaddr = kmap(page);
 164                 status = mapping->a_ops->prepare_write(NULL, page, offset,
 165                                                         offset + bytes);
 166                 if (status) {
 167                         goto unlock;
 168                 }
 169
 170                 memset((void *) (kaddr + offset), 0, bytes);
 171                 flush_dcache_page(page);
 172                 status = mapping->a_ops->commit_write(NULL, page, offset,
 173                                                         offset + bytes);
 174                 if (!status) {
 175                         pos += bytes;
 176                         count -= bytes;
 177                         if (pos > i_size_read(ip))
 178                                 i_size_write(ip, pos < end_size ? pos : end_size);
 179                 }
 180
 181 unlock:
 182                 kunmap(page);
 183                 unlock_page(page);
 184                 page_cache_release(page);
 185                 if (status)
 186                         break;
 187         } while (count);
 188
 189         return (-status);
 190 }
 191
 192 ssize_t                 /* bytes read, or (-)  error */
 193 xfs_read(
 194         bhv_desc_t              *bdp,
 195         struct kiocb            *iocb,
 196         const struct iovec      *iovp,
 197         unsigned int            segs,
 198         loff_t                  *offset,
 199         int                     ioflags,
 200         cred_t                  *credp)
 201 {
 202         struct file             *file = iocb->ki_filp;
 203         struct inode            *inode = file->f_mapping->host;
 204         size_t                  size = 0;
 205         ssize_t                 ret;
 206         xfs_fsize_t             n;
 207         xfs_inode_t             *ip;
 208         xfs_mount_t             *mp;
 209         vnode_t                 *vp;
 210         unsigned long           seg;
 211
 212         ip = XFS_BHVTOI(bdp);
 213         vp = BHV_TO_VNODE(bdp);
 214         mp = ip->i_mount;
 215
 216         XFS_STATS_INC(xs_read_calls);
 217
 218         /* START copy & waste from filemap.c */
 219         for (seg = 0; seg < segs; seg++) {
 220                 const struct iovec *iv = &iovp[seg];
 221
 222                 /*
 223                  * If any segment has a negative length, or the cumulative
 224                  * length ever wraps negative then return -EINVAL.
 225                  */
 226                 size += iv->iov_len;
 227                 if (unlikely((ssize_t)(size|iv->iov_len) < 0))
 228                         return XFS_ERROR(-EINVAL);
 229         }
 230         /* END copy & waste from filemap.c */
 231
 232         if (unlikely(ioflags & IO_ISDIRECT)) {
 233                 xfs_buftarg_t   *target =
 234                         (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 235                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 236                 if ((*offset & target->bt_smask) ||
 237                     (size & target->bt_smask)) {
 238                         if (*offset == ip->i_d.di_size) {
 239                                 return (0);
 240                         }
 241                         return -XFS_ERROR(EINVAL);
 242                 }
 243         }
 244
 245         n = XFS_MAXIOFFSET(mp) - *offset;
 246         if ((n <= 0) || (size == 0))
 247                 return 0;
 248
 249         if (n < size)
 250                 size = n;
 251
 252         if (XFS_FORCED_SHUTDOWN(mp))
 253                 return -EIO;
 254
 255         if (unlikely(ioflags & IO_ISDIRECT))
 256                 mutex_lock(&inode->i_mutex);
 257         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 258
 259         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
 260             !(ioflags & IO_INVIS)) {
 261                 vrwlock_t locktype = VRWLOCK_READ;
 262                 int dmflags = FILP_DELAY_FLAG(file) | DM_SEM_FLAG_RD(ioflags);
 263
 264                 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
 265                                         BHV_TO_VNODE(bdp), *offset, size,
 266                                         dmflags, &locktype);
 267                 if (ret) {
 268                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 269                         goto unlock_mutex;
 270                 }
 271         }
 272
 273         if (unlikely((ioflags & IO_ISDIRECT) && VN_CACHED(vp)))
 274                 VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(*offset)),
 275                                                 -1, FI_REMAPF_LOCKED);
 276
 277         xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
 278                                 (void *)iovp, segs, *offset, ioflags);
 279         ret = __generic_file_aio_read(iocb, iovp, segs, offset);
 280         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 281                 ret = wait_on_sync_kiocb(iocb);
 282         if (ret > 0)
 283                 XFS_STATS_ADD(xs_read_bytes, ret);
 284
 285         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 286
 287 unlock_mutex:
 288         if (unlikely(ioflags & IO_ISDIRECT))
 289                 mutex_unlock(&inode->i_mutex);
 290         return ret;
 291 }
 292
 293 ssize_t
 294 xfs_sendfile(
 295         bhv_desc_t              *bdp,
 296         struct file             *filp,
 297         loff_t                  *offset,
 298         int                     ioflags,
 299         size_t                  count,
 300         read_actor_t            actor,
 301         void                    *target,
 302         cred_t                  *credp)
 303 {
 304         ssize_t                 ret;
 305         xfs_fsize_t             n;
 306         xfs_inode_t             *ip;
 307         xfs_mount_t             *mp;
 308         vnode_t                 *vp;
 309
 310         ip = XFS_BHVTOI(bdp);
 311         vp = BHV_TO_VNODE(bdp);
 312         mp = ip->i_mount;
 313
 314         XFS_STATS_INC(xs_read_calls);
 315
 316         n = XFS_MAXIOFFSET(mp) - *offset;
 317         if ((n <= 0) || (count == 0))
 318                 return 0;
 319
 320         if (n < count)
 321                 count = n;
 322
 323         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 324                 return -EIO;
 325
 326         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 327
 328         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
 329             (!(ioflags & IO_INVIS))) {
 330                 vrwlock_t locktype = VRWLOCK_READ;
 331                 int error;
 332
 333                 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp), *offset, count,
 334                                       FILP_DELAY_FLAG(filp), &locktype);
 335                 if (error) {
 336                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 337                         return -error;
 338                 }
 339         }
 340         xfs_rw_enter_trace(XFS_SENDFILE_ENTER, &ip->i_iocore,
 341                    (void *)(unsigned long)target, count, *offset, ioflags);
 342         ret = generic_file_sendfile(filp, offset, count, actor, target);
 343
 344         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 345
 346         if (ret > 0)
 347                 XFS_STATS_ADD(xs_read_bytes, ret);
 348
 349         return ret;
 350 }
 351
 352 /*
 353  * This routine is called to handle zeroing any space in the last
 354  * block of the file that is beyond the EOF.  We do this since the
 355  * size is being increased without writing anything to that block
 356  * and we don't want anyone to read the garbage on the disk.
 357  */
 358 STATIC int                              /* error (positive) */
 359 xfs_zero_last_block(
 360         struct inode    *ip,
 361         xfs_iocore_t    *io,
 362         xfs_fsize_t     isize,
 363         xfs_fsize_t     end_size)
 364 {
 365         xfs_fileoff_t   last_fsb;
 366         xfs_mount_t     *mp;
 367         int             nimaps;
 368         int             zero_offset;
 369         int             zero_len;
 370         int             error = 0;
 371         xfs_bmbt_irec_t imap;
 372         loff_t          loff;
 373
 374         ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
 375
 376         mp = io->io_mount;
 377
 378         zero_offset = XFS_B_FSB_OFFSET(mp, isize);
 379         if (zero_offset == 0) {
 380                 /*
 381                  * There are no extra bytes in the last block on disk to
 382                  * zero, so return.
 383                  */
 384                 return 0;
 385         }
 386
 387         last_fsb = XFS_B_TO_FSBT(mp, isize);
 388         nimaps = 1;
 389         error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
 390                           &nimaps, NULL);
 391         if (error) {
 392                 return error;
 393         }
 394         ASSERT(nimaps > 0);
 395         /*
 396          * If the block underlying isize is just a hole, then there
 397          * is nothing to zero.
 398          */
 399         if (imap.br_startblock == HOLESTARTBLOCK) {
 400                 return 0;
 401         }
 402         /*
 403          * Zero the part of the last block beyond the EOF, and write it
 404          * out sync.  We need to drop the ilock while we do this so we
 405          * don't deadlock when the buffer cache calls back to us.
 406          */
 407         XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
 408         loff = XFS_FSB_TO_B(mp, last_fsb);
 409
 410         zero_len = mp->m_sb.sb_blocksize - zero_offset;
 411
 412         error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
 413
 414         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 415         ASSERT(error >= 0);
 416         return error;
 417 }
 418
 419 /*
 420  * Zero any on disk space between the current EOF and the new,
 421  * larger EOF.  This handles the normal case of zeroing the remainder
 422  * of the last block in the file and the unusual case of zeroing blocks
 423  * out beyond the size of the file.  This second case only happens
 424  * with fixed size extents and when the system crashes before the inode
 425  * size was updated but after blocks were allocated.  If fill is set,
 426  * then any holes in the range are filled and zeroed.  If not, the holes
 427  * are left alone as holes.
 428  */
 429
 430 int                                     /* error (positive) */
 431 xfs_zero_eof(
 432         vnode_t         *vp,
 433         xfs_iocore_t    *io,
 434         xfs_off_t       offset,         /* starting I/O offset */
 435         xfs_fsize_t     isize,          /* current inode size */
 436         xfs_fsize_t     end_size)       /* terminal inode size */
 437 {
 438         struct inode    *ip = vn_to_inode(vp);
 439         xfs_fileoff_t   start_zero_fsb;
 440         xfs_fileoff_t   end_zero_fsb;
 441         xfs_fileoff_t   zero_count_fsb;
 442         xfs_fileoff_t   last_fsb;
 443         xfs_extlen_t    buf_len_fsb;
 444         xfs_mount_t     *mp;
 445         int             nimaps;
 446         int             error = 0;
 447         xfs_bmbt_irec_t imap;
 448
 449         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 450         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 451         ASSERT(offset > isize);
 452
 453         mp = io->io_mount;
 454
 455         /*
 456          * First handle zeroing the block on which isize resides.
 457          * We only zero a part of that block so it is handled specially.
 458          */
 459         error = xfs_zero_last_block(ip, io, isize, end_size);
 460         if (error) {
 461                 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 462                 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 463                 return error;
 464         }
 465
 466         /*
 467          * Calculate the range between the new size and the old
 468          * where blocks needing to be zeroed may exist.  To get the
 469          * block where the last byte in the file currently resides,
 470          * we need to subtract one from the size and truncate back
 471          * to a block boundary.  We subtract 1 in case the size is
 472          * exactly on a block boundary.
 473          */
 474         last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
 475         start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
 476         end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
 477         ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
 478         if (last_fsb == end_zero_fsb) {
 479                 /*
 480                  * The size was only incremented on its last block.
 481                  * We took care of that above, so just return.
 482                  */
 483                 return 0;
 484         }
 485
 486         ASSERT(start_zero_fsb <= end_zero_fsb);
 487         while (start_zero_fsb <= end_zero_fsb) {
 488                 nimaps = 1;
 489                 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
 490                 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
 491                                   0, NULL, 0, &imap, &nimaps, NULL);
 492                 if (error) {
 493                         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 494                         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 495                         return error;
 496                 }
 497                 ASSERT(nimaps > 0);
 498
 499                 if (imap.br_state == XFS_EXT_UNWRITTEN ||
 500                     imap.br_startblock == HOLESTARTBLOCK) {
 501                         /*
 502                          * This loop handles initializing pages that were
 503                          * partially initialized by the code below this
 504                          * loop. It basically zeroes the part of the page
 505                          * that sits on a hole and sets the page as P_HOLE
 506                          * and calls remapf if it is a mapped file.
 507                          */
 508                         start_zero_fsb = imap.br_startoff + imap.br_blockcount;
 509                         ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 510                         continue;
 511                 }
 512
 513                 /*
 514                  * There are blocks in the range requested.
 515                  * Zero them a single write at a time.  We actually
 516                  * don't zero the entire range returned if it is
 517                  * too big and simply loop around to get the rest.
 518                  * That is not the most efficient thing to do, but it
 519                  * is simple and this path should not be exercised often.
 520                  */
 521                 buf_len_fsb = XFS_FILBLKS_MIN(imap.br_blockcount,
 522                                               mp->m_writeio_blocks << 8);
 523                 /*
 524                  * Drop the inode lock while we're doing the I/O.
 525                  * We'll still have the iolock to protect us.
 526                  */
 527                 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 528
 529                 error = xfs_iozero(ip,
 530                                    XFS_FSB_TO_B(mp, start_zero_fsb),
 531                                    XFS_FSB_TO_B(mp, buf_len_fsb),
 532                                    end_size);
 533
 534                 if (error) {
 535                         goto out_lock;
 536                 }
 537
 538                 start_zero_fsb = imap.br_startoff + buf_len_fsb;
 539                 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 540
 541                 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 542         }
 543
 544         return 0;
 545
 546 out_lock:
 547
 548         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 549         ASSERT(error >= 0);
 550         return error;
 551 }
 552
 553 ssize_t                         /* bytes written, or (-) error */
 554 xfs_write(
 555         bhv_desc_t              *bdp,
 556         struct kiocb            *iocb,
 557         const struct iovec      *iovp,
 558         unsigned int            nsegs,
 559         loff_t                  *offset,
 560         int                     ioflags,
 561         cred_t                  *credp)
 562 {
 563         struct file             *file = iocb->ki_filp;
 564         struct address_space    *mapping = file->f_mapping;
 565         struct inode            *inode = mapping->host;
 566         unsigned long           segs = nsegs;
 567         xfs_inode_t             *xip;
 568         xfs_mount_t             *mp;
 569         ssize_t                 ret = 0, error = 0;
 570         xfs_fsize_t             isize, new_size;
 571         xfs_iocore_t            *io;
 572         vnode_t                 *vp;
 573         unsigned long           seg;
 574         int                     iolock;
 575         int                     eventsent = 0;
 576         vrwlock_t               locktype;
 577         size_t                  ocount = 0, count;
 578         loff_t                  pos;
 579         int                     need_i_mutex = 1, need_flush = 0;
 580
 581         XFS_STATS_INC(xs_write_calls);
 582
 583         vp = BHV_TO_VNODE(bdp);
 584         xip = XFS_BHVTOI(bdp);
 585
 586         for (seg = 0; seg < segs; seg++) {
 587                 const struct iovec *iv = &iovp[seg];
 588
 589                 /*
 590                  * If any segment has a negative length, or the cumulative
 591                  * length ever wraps negative then return -EINVAL.
 592                  */
 593                 ocount += iv->iov_len;
 594                 if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
 595                         return -EINVAL;
 596                 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
 597                         continue;
 598                 if (seg == 0)
 599                         return -EFAULT;
 600                 segs = seg;
 601                 ocount -= iv->iov_len;  /* This segment is no good */
 602                 break;
 603         }
 604
 605         count = ocount;
 606         pos = *offset;
 607
 608         if (count == 0)
 609                 return 0;
 610
 611         io = &xip->i_iocore;
 612         mp = io->io_mount;
 613
 614         if (XFS_FORCED_SHUTDOWN(mp))
 615                 return -EIO;
 616
 617         fs_check_frozen(vp->v_vfsp, SB_FREEZE_WRITE);
 618
 619         if (ioflags & IO_ISDIRECT) {
 620                 xfs_buftarg_t   *target =
 621                         (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 622                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 623
 624                 if ((pos & target->bt_smask) || (count & target->bt_smask))
 625                         return XFS_ERROR(-EINVAL);
 626
 627                 if (!VN_CACHED(vp) && pos < i_size_read(inode))
 628                         need_i_mutex = 0;
 629
 630                 if (VN_CACHED(vp))
 631                         need_flush = 1;
 632         }
 633
 634 relock:
 635         if (need_i_mutex) {
 636                 iolock = XFS_IOLOCK_EXCL;
 637                 locktype = VRWLOCK_WRITE;
 638
 639                 mutex_lock(&inode->i_mutex);
 640         } else {
 641                 iolock = XFS_IOLOCK_SHARED;
 642                 locktype = VRWLOCK_WRITE_DIRECT;
 643         }
 644
 645         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
 646
 647         isize = i_size_read(inode);
 648
 649         if (file->f_flags & O_APPEND)
 650                 *offset = isize;
 651
 652 start:
 653         error = -generic_write_checks(file, &pos, &count,
 654                                         S_ISBLK(inode->i_mode));
 655         if (error) {
 656                 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 657                 goto out_unlock_mutex;
 658         }
 659
 660         new_size = pos + count;
 661         if (new_size > isize)
 662                 io->io_new_size = new_size;
 663
 664         if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
 665             !(ioflags & IO_INVIS) && !eventsent)) {
 666                 loff_t          savedsize = pos;
 667                 int             dmflags = FILP_DELAY_FLAG(file);
 668
 669                 if (need_i_mutex)
 670                         dmflags |= DM_FLAGS_IMUX;
 671
 672                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 673                 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
 674                                       pos, count,
 675                                       dmflags, &locktype);
 676                 if (error) {
 677                         xfs_iunlock(xip, iolock);
 678                         goto out_unlock_mutex;
 679                 }
 680                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 681                 eventsent = 1;
 682
 683                 /*
 684                  * The iolock was dropped and reaquired in XFS_SEND_DATA
 685                  * so we have to recheck the size when appending.
 686                  * We will only "goto start;" once, since having sent the
 687                  * event prevents another call to XFS_SEND_DATA, which is
 688                  * what allows the size to change in the first place.
 689                  */
 690                 if ((file->f_flags & O_APPEND) && savedsize != isize) {
 691                         pos = isize = xip->i_d.di_size;
 692                         goto start;
 693                 }
 694         }
 695
 696         if (likely(!(ioflags & IO_INVIS))) {
 697                 file_update_time(file);
 698                 xfs_ichgtime_fast(xip, inode,
 699                                   XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 700         }
 701
 702         /*
 703          * If the offset is beyond the size of the file, we have a couple
 704          * of things to do. First, if there is already space allocated
 705          * we need to either create holes or zero the disk or ...
 706          *
 707          * If there is a page where the previous size lands, we need
 708          * to zero it out up to the new size.
 709          */
 710
 711         if (pos > isize) {
 712                 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
 713                                         isize, pos + count);
 714                 if (error) {
 715                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 716                         goto out_unlock_mutex;
 717                 }
 718         }
 719         xfs_iunlock(xip, XFS_ILOCK_EXCL);
 720
 721         /*
 722          * If we're writing the file then make sure to clear the
 723          * setuid and setgid bits if the process is not being run
 724          * by root.  This keeps people from modifying setuid and
 725          * setgid binaries.
 726          */
 727
 728         if (((xip->i_d.di_mode & S_ISUID) ||
 729             ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
 730                 (S_ISGID | S_IXGRP))) &&
 731              !capable(CAP_FSETID)) {
 732                 error = xfs_write_clear_setuid(xip);
 733                 if (likely(!error))
 734                         error = -remove_suid(file->f_dentry);
 735                 if (unlikely(error)) {
 736                         xfs_iunlock(xip, iolock);
 737                         goto out_unlock_mutex;
 738                 }
 739         }
 740
 741 retry:
 742         /* We can write back this queue in page reclaim */
 743         current->backing_dev_info = mapping->backing_dev_info;
 744
 745         if ((ioflags & IO_ISDIRECT)) {
 746                 if (need_flush) {
 747                         xfs_inval_cached_trace(io, pos, -1,
 748                                         ctooff(offtoct(pos)), -1);
 749                         VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(pos)),
 750                                         -1, FI_REMAPF_LOCKED);
 751                 }
 752
 753                 if (need_i_mutex) {
 754                         /* demote the lock now the cached pages are gone */
 755                         XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
 756                         mutex_unlock(&inode->i_mutex);
 757
 758                         iolock = XFS_IOLOCK_SHARED;
 759                         locktype = VRWLOCK_WRITE_DIRECT;
 760                         need_i_mutex = 0;
 761                 }
 762
 763                 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
 764                                 *offset, ioflags);
 765                 ret = generic_file_direct_write(iocb, iovp,
 766                                 &segs, pos, offset, count, ocount);
 767
 768                 /*
 769                  * direct-io write to a hole: fall through to buffered I/O
 770                  * for completing the rest of the request.
 771                  */
 772                 if (ret >= 0 && ret != count) {
 773                         XFS_STATS_ADD(xs_write_bytes, ret);
 774
 775                         pos += ret;
 776                         count -= ret;
 777
 778                         need_i_mutex = 1;
 779                         ioflags &= ~IO_ISDIRECT;
 780                         xfs_iunlock(xip, iolock);
 781                         goto relock;
 782                 }
 783         } else {
 784                 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
 785                                 *offset, ioflags);
 786                 ret = generic_file_buffered_write(iocb, iovp, segs,
 787                                 pos, offset, count, ret);
 788         }
 789
 790         current->backing_dev_info = NULL;
 791
 792         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 793                 ret = wait_on_sync_kiocb(iocb);
 794
 795         if ((ret == -ENOSPC) &&
 796             DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
 797             !(ioflags & IO_INVIS)) {
 798
 799                 xfs_rwunlock(bdp, locktype);
 800                 if (need_i_mutex)
 801                         mutex_unlock(&inode->i_mutex);
 802                 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
 803                                 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
 804                                 0, 0, 0); /* Delay flag intentionally  unused */
 805                 if (error)
 806                         goto out_nounlocks;
 807                 if (need_i_mutex)
 808                         mutex_lock(&inode->i_mutex);
 809                 xfs_rwlock(bdp, locktype);
 810                 pos = xip->i_d.di_size;
 811                 ret = 0;
 812                 goto retry;
 813         }
 814
 815         isize = i_size_read(inode);
 816         if (unlikely(ret < 0 && ret != -EFAULT && *offset > isize))
 817                 *offset = isize;
 818
 819         if (*offset > xip->i_d.di_size) {
 820                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 821                 if (*offset > xip->i_d.di_size) {
 822                         xip->i_d.di_size = *offset;
 823                         i_size_write(inode, *offset);
 824                         xip->i_update_core = 1;
 825                         xip->i_update_size = 1;
 826                 }
 827                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 828         }
 829
 830         error = -ret;
 831         if (ret <= 0)
 832                 goto out_unlock_internal;
 833
 834         XFS_STATS_ADD(xs_write_bytes, ret);
 835
 836         /* Handle various SYNC-type writes */
 837         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
 838                 /*
 839                  * If we're treating this as O_DSYNC and we have not updated the
 840                  * size, force the log.
 841                  */
 842                 if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
 843                     !(xip->i_update_size)) {
 844                         xfs_inode_log_item_t    *iip = xip->i_itemp;
 845
 846                         /*
 847                          * If an allocation transaction occurred
 848                          * without extending the size, then we have to force
 849                          * the log up the proper point to ensure that the
 850                          * allocation is permanent.  We can't count on
 851                          * the fact that buffered writes lock out direct I/O
 852                          * writes - the direct I/O write could have extended
 853                          * the size nontransactionally, then finished before
 854                          * we started.  xfs_write_file will think that the file
 855                          * didn't grow but the update isn't safe unless the
 856                          * size change is logged.
 857                          *
 858                          * Force the log if we've committed a transaction
 859                          * against the inode or if someone else has and
 860                          * the commit record hasn't gone to disk (e.g.
 861                          * the inode is pinned).  This guarantees that
 862                          * all changes affecting the inode are permanent
 863                          * when we return.
 864                          */
 865                         if (iip && iip->ili_last_lsn) {
 866                                 xfs_log_force(mp, iip->ili_last_lsn,
 867                                                 XFS_LOG_FORCE | XFS_LOG_SYNC);
 868                         } else if (xfs_ipincount(xip) > 0) {
 869                                 xfs_log_force(mp, (xfs_lsn_t)0,
 870                                                 XFS_LOG_FORCE | XFS_LOG_SYNC);
 871                         }
 872
 873                 } else {
 874                         xfs_trans_t     *tp;
 875
 876                         /*
 877                          * O_SYNC or O_DSYNC _with_ a size update are handled
 878                          * the same way.
 879                          *
 880                          * If the write was synchronous then we need to make
 881                          * sure that the inode modification time is permanent.
 882                          * We'll have updated the timestamp above, so here
 883                          * we use a synchronous transaction to log the inode.
 884                          * It's not fast, but it's necessary.
 885                          *
 886                          * If this a dsync write and the size got changed
 887                          * non-transactionally, then we need to ensure that
 888                          * the size change gets logged in a synchronous
 889                          * transaction.
 890                          */
 891
 892                         tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
 893                         if ((error = xfs_trans_reserve(tp, 0,
 894                                                       XFS_SWRITE_LOG_RES(mp),
 895                                                       0, 0, 0))) {
 896                                 /* Transaction reserve failed */
 897                                 xfs_trans_cancel(tp, 0);
 898                         } else {
 899                                 /* Transaction reserve successful */
 900                                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 901                                 xfs_trans_ijoin(tp, xip, XFS_ILOCK_EXCL);
 902                                 xfs_trans_ihold(tp, xip);
 903                                 xfs_trans_log_inode(tp, xip, XFS_ILOG_CORE);
 904                                 xfs_trans_set_sync(tp);
 905                                 error = xfs_trans_commit(tp, 0, NULL);
 906                                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 907                         }
 908                         if (error)
 909                                 goto out_unlock_internal;
 910                 }
 911
 912                 xfs_rwunlock(bdp, locktype);
 913                 if (need_i_mutex)
 914                         mutex_unlock(&inode->i_mutex);
 915
 916                 error = sync_page_range(inode, mapping, pos, ret);
 917                 if (!error)
 918                         error = ret;
 919                 return error;
 920         }
 921
 922  out_unlock_internal:
 923         xfs_rwunlock(bdp, locktype);
 924  out_unlock_mutex:
 925         if (need_i_mutex)
 926                 mutex_unlock(&inode->i_mutex);
 927  out_nounlocks:
 928         return -error;
 929 }
 930
 931 /*
 932  * All xfs metadata buffers except log state machine buffers
 933  * get this attached as their b_bdstrat callback function.
 934  * This is so that we can catch a buffer
 935  * after prematurely unpinning it to forcibly shutdown the filesystem.
 936  */
 937 int
 938 xfs_bdstrat_cb(struct xfs_buf *bp)
 939 {
 940         xfs_mount_t     *mp;
 941
 942         mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
 943         if (!XFS_FORCED_SHUTDOWN(mp)) {
 944                 xfs_buf_iorequest(bp);
 945                 return 0;
 946         } else {
 947                 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
 948                 /*
 949                  * Metadata write that didn't get logged but
 950                  * written delayed anyway. These aren't associated
 951                  * with a transaction, and can be ignored.
 952                  */
 953                 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
 954                     (XFS_BUF_ISREAD(bp)) == 0)
 955                         return (xfs_bioerror_relse(bp));
 956                 else
 957                         return (xfs_bioerror(bp));
 958         }
 959 }
 960
 961
 962 int
 963 xfs_bmap(bhv_desc_t     *bdp,
 964         xfs_off_t       offset,
 965         ssize_t         count,
 966         int             flags,
 967         xfs_iomap_t     *iomapp,
 968         int             *niomaps)
 969 {
 970         xfs_inode_t     *ip = XFS_BHVTOI(bdp);
 971         xfs_iocore_t    *io = &ip->i_iocore;
 972
 973         ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
 974         ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
 975                ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
 976
 977         return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
 978 }
 979
 980 /*
 981  * Wrapper around bdstrat so that we can stop data
 982  * from going to disk in case we are shutting down the filesystem.
 983  * Typically user data goes thru this path; one of the exceptions
 984  * is the superblock.
 985  */
 986 int
 987 xfsbdstrat(
 988         struct xfs_mount        *mp,
 989         struct xfs_buf          *bp)
 990 {
 991         ASSERT(mp);
 992         if (!XFS_FORCED_SHUTDOWN(mp)) {
 993                 /* Grio redirection would go here
 994                  * if (XFS_BUF_IS_GRIO(bp)) {
 995                  */
 996
 997                 xfs_buf_iorequest(bp);
 998                 return 0;
 999         }
1000
1001         xfs_buftrace("XFSBDSTRAT IOERROR", bp);
1002         return (xfs_bioerror_relse(bp));
1003 }
1004
1005 /*
1006  * If the underlying (data/log/rt) device is readonly, there are some
1007  * operations that cannot proceed.
1008  */
1009 int
1010 xfs_dev_is_read_only(
1011         xfs_mount_t             *mp,
1012         char                    *message)
1013 {
1014         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1015             xfs_readonly_buftarg(mp->m_logdev_targp) ||
1016             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1017                 cmn_err(CE_NOTE,
1018                         "XFS: %s required on read-only device.", message);
1019                 cmn_err(CE_NOTE,
1020                         "XFS: write access unavailable, cannot proceed.");
1021                 return EROFS;
1022         }
1023         return 0;
1024 }