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