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_dir2.h"
  27 #include "xfs_alloc.h"
  28 #include "xfs_dmapi.h"
  29 #include "xfs_quota.h"
  30 #include "xfs_mount.h"
  31 #include "xfs_bmap_btree.h"
  32 #include "xfs_alloc_btree.h"
  33 #include "xfs_ialloc_btree.h"
  34 #include "xfs_dir2_sf.h"
  35 #include "xfs_attr_sf.h"
  36 #include "xfs_dinode.h"
  37 #include "xfs_inode.h"
  38 #include "xfs_bmap.h"
  39 #include "xfs_btree.h"
  40 #include "xfs_ialloc.h"
  41 #include "xfs_rtalloc.h"
  42 #include "xfs_error.h"
  43 #include "xfs_itable.h"
  44 #include "xfs_rw.h"
  45 #include "xfs_acl.h"
  46 #include "xfs_cap.h"
  47 #include "xfs_mac.h"
  48 #include "xfs_attr.h"
  49 #include "xfs_inode_item.h"
  50 #include "xfs_buf_item.h"
  51 #include "xfs_utils.h"
  52 #include "xfs_iomap.h"
  53
  54 #include <linux/capability.h>
  55 #include <linux/writeback.h>
  56
  57
  58 #if defined(XFS_RW_TRACE)
  59 void
  60 xfs_rw_enter_trace(
  61         int                     tag,
  62         xfs_iocore_t            *io,
  63         void                    *data,
  64         size_t                  segs,
  65         loff_t                  offset,
  66         int                     ioflags)
  67 {
  68         xfs_inode_t     *ip = XFS_IO_INODE(io);
  69
  70         if (ip->i_rwtrace == NULL)
  71                 return;
  72         ktrace_enter(ip->i_rwtrace,
  73                 (void *)(unsigned long)tag,
  74                 (void *)ip,
  75                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
  76                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
  77                 (void *)data,
  78                 (void *)((unsigned long)segs),
  79                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
  80                 (void *)((unsigned long)(offset & 0xffffffff)),
  81                 (void *)((unsigned long)ioflags),
  82                 (void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
  83                 (void *)((unsigned long)(io->io_new_size & 0xffffffff)),
  84                 (void *)((unsigned long)current_pid()),
  85                 (void *)NULL,
  86                 (void *)NULL,
  87                 (void *)NULL,
  88                 (void *)NULL);
  89 }
  90
  91 void
  92 xfs_inval_cached_trace(
  93         xfs_iocore_t    *io,
  94         xfs_off_t       offset,
  95         xfs_off_t       len,
  96         xfs_off_t       first,
  97         xfs_off_t       last)
  98 {
  99         xfs_inode_t     *ip = XFS_IO_INODE(io);
 100
 101         if (ip->i_rwtrace == NULL)
 102                 return;
 103         ktrace_enter(ip->i_rwtrace,
 104                 (void *)(__psint_t)XFS_INVAL_CACHED,
 105                 (void *)ip,
 106                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
 107                 (void *)((unsigned long)(offset & 0xffffffff)),
 108                 (void *)((unsigned long)((len >> 32) & 0xffffffff)),
 109                 (void *)((unsigned long)(len & 0xffffffff)),
 110                 (void *)((unsigned long)((first >> 32) & 0xffffffff)),
 111                 (void *)((unsigned long)(first & 0xffffffff)),
 112                 (void *)((unsigned long)((last >> 32) & 0xffffffff)),
 113                 (void *)((unsigned long)(last & 0xffffffff)),
 114                 (void *)((unsigned long)current_pid()),
 115                 (void *)NULL,
 116                 (void *)NULL,
 117                 (void *)NULL,
 118                 (void *)NULL,
 119                 (void *)NULL);
 120 }
 121 #endif
 122
 123 /*
 124  *      xfs_iozero
 125  *
 126  *      xfs_iozero clears the specified range of buffer supplied,
 127  *      and marks all the affected blocks as valid and modified.  If
 128  *      an affected block is not allocated, it will be allocated.  If
 129  *      an affected block is not completely overwritten, and is not
 130  *      valid before the operation, it will be read from disk before
 131  *      being partially zeroed.
 132  */
 133 STATIC int
 134 xfs_iozero(
 135         struct inode            *ip,    /* inode                        */
 136         loff_t                  pos,    /* offset in file               */
 137         size_t                  count,  /* size of data to zero         */
 138         loff_t                  end_size)       /* max file size to set */
 139 {
 140         unsigned                bytes;
 141         struct page             *page;
 142         struct address_space    *mapping;
 143         char                    *kaddr;
 144         int                     status;
 145
 146         mapping = ip->i_mapping;
 147         do {
 148                 unsigned long index, offset;
 149
 150                 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
 151                 index = pos >> PAGE_CACHE_SHIFT;
 152                 bytes = PAGE_CACHE_SIZE - offset;
 153                 if (bytes > count)
 154                         bytes = count;
 155
 156                 status = -ENOMEM;
 157                 page = grab_cache_page(mapping, index);
 158                 if (!page)
 159                         break;
 160
 161                 kaddr = kmap(page);
 162                 status = mapping->a_ops->prepare_write(NULL, page, offset,
 163                                                         offset + bytes);
 164                 if (status) {
 165                         goto unlock;
 166                 }
 167
 168                 memset((void *) (kaddr + offset), 0, bytes);
 169                 flush_dcache_page(page);
 170                 status = mapping->a_ops->commit_write(NULL, page, offset,
 171                                                         offset + bytes);
 172                 if (!status) {
 173                         pos += bytes;
 174                         count -= bytes;
 175                         if (pos > i_size_read(ip))
 176                                 i_size_write(ip, pos < end_size ? pos : end_size);
 177                 }
 178
 179 unlock:
 180                 kunmap(page);
 181                 unlock_page(page);
 182                 page_cache_release(page);
 183                 if (status)
 184                         break;
 185         } while (count);
 186
 187         return (-status);
 188 }
 189
 190 ssize_t                 /* bytes read, or (-)  error */
 191 xfs_read(
 192         bhv_desc_t              *bdp,
 193         struct kiocb            *iocb,
 194         const struct iovec      *iovp,
 195         unsigned int            segs,
 196         loff_t                  *offset,
 197         int                     ioflags,
 198         cred_t                  *credp)
 199 {
 200         struct file             *file = iocb->ki_filp;
 201         struct inode            *inode = file->f_mapping->host;
 202         size_t                  size = 0;
 203         ssize_t                 ret;
 204         xfs_fsize_t             n;
 205         xfs_inode_t             *ip;
 206         xfs_mount_t             *mp;
 207         bhv_vnode_t             *vp;
 208         unsigned long           seg;
 209
 210         ip = XFS_BHVTOI(bdp);
 211         vp = BHV_TO_VNODE(bdp);
 212         mp = ip->i_mount;
 213
 214         XFS_STATS_INC(xs_read_calls);
 215
 216         /* START copy & waste from filemap.c */
 217         for (seg = 0; seg < segs; seg++) {
 218                 const struct iovec *iv = &iovp[seg];
 219
 220                 /*
 221                  * If any segment has a negative length, or the cumulative
 222                  * length ever wraps negative then return -EINVAL.
 223                  */
 224                 size += iv->iov_len;
 225                 if (unlikely((ssize_t)(size|iv->iov_len) < 0))
 226                         return XFS_ERROR(-EINVAL);
 227         }
 228         /* END copy & waste from filemap.c */
 229
 230         if (unlikely(ioflags & IO_ISDIRECT)) {
 231                 xfs_buftarg_t   *target =
 232                         (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 233                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 234                 if ((*offset & target->bt_smask) ||
 235                     (size & target->bt_smask)) {
 236                         if (*offset == ip->i_d.di_size) {
 237                                 return (0);
 238                         }
 239                         return -XFS_ERROR(EINVAL);
 240                 }
 241         }
 242
 243         n = XFS_MAXIOFFSET(mp) - *offset;
 244         if ((n <= 0) || (size == 0))
 245                 return 0;
 246
 247         if (n < size)
 248                 size = n;
 249
 250         if (XFS_FORCED_SHUTDOWN(mp))
 251                 return -EIO;
 252
 253         if (unlikely(ioflags & IO_ISDIRECT))
 254                 mutex_lock(&inode->i_mutex);
 255         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 256
 257         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
 258             !(ioflags & IO_INVIS)) {
 259                 bhv_vrwlock_t locktype = VRWLOCK_READ;
 260                 int dmflags = FILP_DELAY_FLAG(file) | DM_SEM_FLAG_RD(ioflags);
 261
 262                 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
 263                                         BHV_TO_VNODE(bdp), *offset, size,
 264                                         dmflags, &locktype);
 265                 if (ret) {
 266                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 267                         goto unlock_mutex;
 268                 }
 269         }
 270
 271         if (unlikely((ioflags & IO_ISDIRECT) && VN_CACHED(vp)))
 272                 bhv_vop_flushinval_pages(vp, ctooff(offtoct(*offset)),
 273                                                 -1, FI_REMAPF_LOCKED);
 274
 275         xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
 276                                 (void *)iovp, segs, *offset, ioflags);
 277         ret = __generic_file_aio_read(iocb, iovp, segs, offset);
 278         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 279                 ret = wait_on_sync_kiocb(iocb);
 280         if (ret > 0)
 281                 XFS_STATS_ADD(xs_read_bytes, ret);
 282
 283         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 284
 285 unlock_mutex:
 286         if (unlikely(ioflags & IO_ISDIRECT))
 287                 mutex_unlock(&inode->i_mutex);
 288         return ret;
 289 }
 290
 291 ssize_t
 292 xfs_sendfile(
 293         bhv_desc_t              *bdp,
 294         struct file             *filp,
 295         loff_t                  *offset,
 296         int                     ioflags,
 297         size_t                  count,
 298         read_actor_t            actor,
 299         void                    *target,
 300         cred_t                  *credp)
 301 {
 302         xfs_inode_t             *ip = XFS_BHVTOI(bdp);
 303         xfs_mount_t             *mp = ip->i_mount;
 304         ssize_t                 ret;
 305
 306         XFS_STATS_INC(xs_read_calls);
 307         if (XFS_FORCED_SHUTDOWN(mp))
 308                 return -EIO;
 309
 310         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 311
 312         if (DM_EVENT_ENABLED(BHV_TO_VNODE(bdp)->v_vfsp, ip, DM_EVENT_READ) &&
 313             (!(ioflags & IO_INVIS))) {
 314                 bhv_vrwlock_t locktype = VRWLOCK_READ;
 315                 int error;
 316
 317                 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp),
 318                                       *offset, count,
 319                                       FILP_DELAY_FLAG(filp), &locktype);
 320                 if (error) {
 321                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 322                         return -error;
 323                 }
 324         }
 325         xfs_rw_enter_trace(XFS_SENDFILE_ENTER, &ip->i_iocore,
 326                    (void *)(unsigned long)target, count, *offset, ioflags);
 327         ret = generic_file_sendfile(filp, offset, count, actor, target);
 328         if (ret > 0)
 329                 XFS_STATS_ADD(xs_read_bytes, ret);
 330
 331         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 332         return ret;
 333 }
 334
 335 ssize_t
 336 xfs_splice_read(
 337         bhv_desc_t              *bdp,
 338         struct file             *infilp,
 339         loff_t                  *ppos,
 340         struct pipe_inode_info  *pipe,
 341         size_t                  count,
 342         int                     flags,
 343         int                     ioflags,
 344         cred_t                  *credp)
 345 {
 346         xfs_inode_t             *ip = XFS_BHVTOI(bdp);
 347         xfs_mount_t             *mp = ip->i_mount;
 348         ssize_t                 ret;
 349
 350         XFS_STATS_INC(xs_read_calls);
 351         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 352                 return -EIO;
 353
 354         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 355
 356         if (DM_EVENT_ENABLED(BHV_TO_VNODE(bdp)->v_vfsp, ip, DM_EVENT_READ) &&
 357             (!(ioflags & IO_INVIS))) {
 358                 bhv_vrwlock_t locktype = VRWLOCK_READ;
 359                 int error;
 360
 361                 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp),
 362                                         *ppos, count,
 363                                         FILP_DELAY_FLAG(infilp), &locktype);
 364                 if (error) {
 365                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 366                         return -error;
 367                 }
 368         }
 369         xfs_rw_enter_trace(XFS_SPLICE_READ_ENTER, &ip->i_iocore,
 370                            pipe, count, *ppos, ioflags);
 371         ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
 372         if (ret > 0)
 373                 XFS_STATS_ADD(xs_read_bytes, ret);
 374
 375         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 376         return ret;
 377 }
 378
 379 ssize_t
 380 xfs_splice_write(
 381         bhv_desc_t              *bdp,
 382         struct pipe_inode_info  *pipe,
 383         struct file             *outfilp,
 384         loff_t                  *ppos,
 385         size_t                  count,
 386         int                     flags,
 387         int                     ioflags,
 388         cred_t                  *credp)
 389 {
 390         xfs_inode_t             *ip = XFS_BHVTOI(bdp);
 391         xfs_mount_t             *mp = ip->i_mount;
 392         ssize_t                 ret;
 393
 394         XFS_STATS_INC(xs_write_calls);
 395         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 396                 return -EIO;
 397
 398         xfs_ilock(ip, XFS_IOLOCK_EXCL);
 399
 400         if (DM_EVENT_ENABLED(BHV_TO_VNODE(bdp)->v_vfsp, ip, DM_EVENT_WRITE) &&
 401             (!(ioflags & IO_INVIS))) {
 402                 bhv_vrwlock_t locktype = VRWLOCK_WRITE;
 403                 int error;
 404
 405                 error = XFS_SEND_DATA(mp, DM_EVENT_WRITE, BHV_TO_VNODE(bdp),
 406                                         *ppos, count,
 407                                         FILP_DELAY_FLAG(outfilp), &locktype);
 408                 if (error) {
 409                         xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 410                         return -error;
 411                 }
 412         }
 413         xfs_rw_enter_trace(XFS_SPLICE_WRITE_ENTER, &ip->i_iocore,
 414                            pipe, count, *ppos, ioflags);
 415         ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
 416         if (ret > 0)
 417                 XFS_STATS_ADD(xs_write_bytes, ret);
 418
 419         xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 420         return ret;
 421 }
 422
 423 /*
 424  * This routine is called to handle zeroing any space in the last
 425  * block of the file that is beyond the EOF.  We do this since the
 426  * size is being increased without writing anything to that block
 427  * and we don't want anyone to read the garbage on the disk.
 428  */
 429 STATIC int                              /* error (positive) */
 430 xfs_zero_last_block(
 431         struct inode    *ip,
 432         xfs_iocore_t    *io,
 433         xfs_fsize_t     isize,
 434         xfs_fsize_t     end_size)
 435 {
 436         xfs_fileoff_t   last_fsb;
 437         xfs_mount_t     *mp = io->io_mount;
 438         int             nimaps;
 439         int             zero_offset;
 440         int             zero_len;
 441         int             error = 0;
 442         xfs_bmbt_irec_t imap;
 443         loff_t          loff;
 444
 445         ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
 446
 447         zero_offset = XFS_B_FSB_OFFSET(mp, isize);
 448         if (zero_offset == 0) {
 449                 /*
 450                  * There are no extra bytes in the last block on disk to
 451                  * zero, so return.
 452                  */
 453                 return 0;
 454         }
 455
 456         last_fsb = XFS_B_TO_FSBT(mp, isize);
 457         nimaps = 1;
 458         error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
 459                           &nimaps, NULL, NULL);
 460         if (error) {
 461                 return error;
 462         }
 463         ASSERT(nimaps > 0);
 464         /*
 465          * If the block underlying isize is just a hole, then there
 466          * is nothing to zero.
 467          */
 468         if (imap.br_startblock == HOLESTARTBLOCK) {
 469                 return 0;
 470         }
 471         /*
 472          * Zero the part of the last block beyond the EOF, and write it
 473          * out sync.  We need to drop the ilock while we do this so we
 474          * don't deadlock when the buffer cache calls back to us.
 475          */
 476         XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
 477
 478         loff = XFS_FSB_TO_B(mp, last_fsb);
 479         zero_len = mp->m_sb.sb_blocksize - zero_offset;
 480         error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
 481
 482         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 483         ASSERT(error >= 0);
 484         return error;
 485 }
 486
 487 /*
 488  * Zero any on disk space between the current EOF and the new,
 489  * larger EOF.  This handles the normal case of zeroing the remainder
 490  * of the last block in the file and the unusual case of zeroing blocks
 491  * out beyond the size of the file.  This second case only happens
 492  * with fixed size extents and when the system crashes before the inode
 493  * size was updated but after blocks were allocated.  If fill is set,
 494  * then any holes in the range are filled and zeroed.  If not, the holes
 495  * are left alone as holes.
 496  */
 497
 498 int                                     /* error (positive) */
 499 xfs_zero_eof(
 500         bhv_vnode_t     *vp,
 501         xfs_iocore_t    *io,
 502         xfs_off_t       offset,         /* starting I/O offset */
 503         xfs_fsize_t     isize,          /* current inode size */
 504         xfs_fsize_t     end_size)       /* terminal inode size */
 505 {
 506         struct inode    *ip = vn_to_inode(vp);
 507         xfs_fileoff_t   start_zero_fsb;
 508         xfs_fileoff_t   end_zero_fsb;
 509         xfs_fileoff_t   zero_count_fsb;
 510         xfs_fileoff_t   last_fsb;
 511         xfs_mount_t     *mp = io->io_mount;
 512         int             nimaps;
 513         int             error = 0;
 514         xfs_bmbt_irec_t imap;
 515
 516         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 517         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 518         ASSERT(offset > isize);
 519
 520         /*
 521          * First handle zeroing the block on which isize resides.
 522          * We only zero a part of that block so it is handled specially.
 523          */
 524         error = xfs_zero_last_block(ip, io, isize, end_size);
 525         if (error) {
 526                 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 527                 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 528                 return error;
 529         }
 530
 531         /*
 532          * Calculate the range between the new size and the old
 533          * where blocks needing to be zeroed may exist.  To get the
 534          * block where the last byte in the file currently resides,
 535          * we need to subtract one from the size and truncate back
 536          * to a block boundary.  We subtract 1 in case the size is
 537          * exactly on a block boundary.
 538          */
 539         last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
 540         start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
 541         end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
 542         ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
 543         if (last_fsb == end_zero_fsb) {
 544                 /*
 545                  * The size was only incremented on its last block.
 546                  * We took care of that above, so just return.
 547                  */
 548                 return 0;
 549         }
 550
 551         ASSERT(start_zero_fsb <= end_zero_fsb);
 552         while (start_zero_fsb <= end_zero_fsb) {
 553                 nimaps = 1;
 554                 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
 555                 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
 556                                   0, NULL, 0, &imap, &nimaps, NULL, NULL);
 557                 if (error) {
 558                         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 559                         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 560                         return error;
 561                 }
 562                 ASSERT(nimaps > 0);
 563
 564                 if (imap.br_state == XFS_EXT_UNWRITTEN ||
 565                     imap.br_startblock == HOLESTARTBLOCK) {
 566                         /*
 567                          * This loop handles initializing pages that were
 568                          * partially initialized by the code below this
 569                          * loop. It basically zeroes the part of the page
 570                          * that sits on a hole and sets the page as P_HOLE
 571                          * and calls remapf if it is a mapped file.
 572                          */
 573                         start_zero_fsb = imap.br_startoff + imap.br_blockcount;
 574                         ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 575                         continue;
 576                 }
 577
 578                 /*
 579                  * There are blocks we need to zero.
 580                  * Drop the inode lock while we're doing the I/O.
 581                  * We'll still have the iolock to protect us.
 582                  */
 583                 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 584
 585                 error = xfs_iozero(ip,
 586                                    XFS_FSB_TO_B(mp, start_zero_fsb),
 587                                    XFS_FSB_TO_B(mp, imap.br_blockcount),
 588                                    end_size);
 589                 if (error) {
 590                         goto out_lock;
 591                 }
 592
 593                 start_zero_fsb = imap.br_startoff + imap.br_blockcount;
 594                 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 595
 596                 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 597         }
 598
 599         return 0;
 600
 601 out_lock:
 602
 603         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 604         ASSERT(error >= 0);
 605         return error;
 606 }
 607
 608 ssize_t                         /* bytes written, or (-) error */
 609 xfs_write(
 610         bhv_desc_t              *bdp,
 611         struct kiocb            *iocb,
 612         const struct iovec      *iovp,
 613         unsigned int            nsegs,
 614         loff_t                  *offset,
 615         int                     ioflags,
 616         cred_t                  *credp)
 617 {
 618         struct file             *file = iocb->ki_filp;
 619         struct address_space    *mapping = file->f_mapping;
 620         struct inode            *inode = mapping->host;
 621         unsigned long           segs = nsegs;
 622         xfs_inode_t             *xip;
 623         xfs_mount_t             *mp;
 624         ssize_t                 ret = 0, error = 0;
 625         xfs_fsize_t             isize, new_size;
 626         xfs_iocore_t            *io;
 627         bhv_vnode_t             *vp;
 628         unsigned long           seg;
 629         int                     iolock;
 630         int                     eventsent = 0;
 631         bhv_vrwlock_t           locktype;
 632         size_t                  ocount = 0, count;
 633         loff_t                  pos;
 634         int                     need_i_mutex = 1, need_flush = 0;
 635
 636         XFS_STATS_INC(xs_write_calls);
 637
 638         vp = BHV_TO_VNODE(bdp);
 639         xip = XFS_BHVTOI(bdp);
 640
 641         for (seg = 0; seg < segs; seg++) {
 642                 const struct iovec *iv = &iovp[seg];
 643
 644                 /*
 645                  * If any segment has a negative length, or the cumulative
 646                  * length ever wraps negative then return -EINVAL.
 647                  */
 648                 ocount += iv->iov_len;
 649                 if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
 650                         return -EINVAL;
 651                 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
 652                         continue;
 653                 if (seg == 0)
 654                         return -EFAULT;
 655                 segs = seg;
 656                 ocount -= iv->iov_len;  /* This segment is no good */
 657                 break;
 658         }
 659
 660         count = ocount;
 661         pos = *offset;
 662
 663         if (count == 0)
 664                 return 0;
 665
 666         io = &xip->i_iocore;
 667         mp = io->io_mount;
 668
 669         vfs_wait_for_freeze(vp->v_vfsp, SB_FREEZE_WRITE);
 670
 671         if (XFS_FORCED_SHUTDOWN(mp))
 672                 return -EIO;
 673
 674         if (ioflags & IO_ISDIRECT) {
 675                 xfs_buftarg_t   *target =
 676                         (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 677                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 678
 679                 if ((pos & target->bt_smask) || (count & target->bt_smask))
 680                         return XFS_ERROR(-EINVAL);
 681
 682                 if (!VN_CACHED(vp) && pos < i_size_read(inode))
 683                         need_i_mutex = 0;
 684
 685                 if (VN_CACHED(vp))
 686                         need_flush = 1;
 687         }
 688
 689 relock:
 690         if (need_i_mutex) {
 691                 iolock = XFS_IOLOCK_EXCL;
 692                 locktype = VRWLOCK_WRITE;
 693
 694                 mutex_lock(&inode->i_mutex);
 695         } else {
 696                 iolock = XFS_IOLOCK_SHARED;
 697                 locktype = VRWLOCK_WRITE_DIRECT;
 698         }
 699
 700         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
 701
 702         isize = i_size_read(inode);
 703
 704         if (file->f_flags & O_APPEND)
 705                 *offset = isize;
 706
 707 start:
 708         error = -generic_write_checks(file, &pos, &count,
 709                                         S_ISBLK(inode->i_mode));
 710         if (error) {
 711                 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 712                 goto out_unlock_mutex;
 713         }
 714
 715         new_size = pos + count;
 716         if (new_size > isize)
 717                 io->io_new_size = new_size;
 718
 719         if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
 720             !(ioflags & IO_INVIS) && !eventsent)) {
 721                 loff_t          savedsize = pos;
 722                 int             dmflags = FILP_DELAY_FLAG(file);
 723
 724                 if (need_i_mutex)
 725                         dmflags |= DM_FLAGS_IMUX;
 726
 727                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 728                 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
 729                                       pos, count,
 730                                       dmflags, &locktype);
 731                 if (error) {
 732                         xfs_iunlock(xip, iolock);
 733                         goto out_unlock_mutex;
 734                 }
 735                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 736                 eventsent = 1;
 737
 738                 /*
 739                  * The iolock was dropped and reacquired in XFS_SEND_DATA
 740                  * so we have to recheck the size when appending.
 741                  * We will only "goto start;" once, since having sent the
 742                  * event prevents another call to XFS_SEND_DATA, which is
 743                  * what allows the size to change in the first place.
 744                  */
 745                 if ((file->f_flags & O_APPEND) && savedsize != isize) {
 746                         pos = isize = xip->i_d.di_size;
 747                         goto start;
 748                 }
 749         }
 750
 751         if (likely(!(ioflags & IO_INVIS))) {
 752                 file_update_time(file);
 753                 xfs_ichgtime_fast(xip, inode,
 754                                   XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 755         }
 756
 757         /*
 758          * If the offset is beyond the size of the file, we have a couple
 759          * of things to do. First, if there is already space allocated
 760          * we need to either create holes or zero the disk or ...
 761          *
 762          * If there is a page where the previous size lands, we need
 763          * to zero it out up to the new size.
 764          */
 765
 766         if (pos > isize) {
 767                 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
 768                                         isize, pos + count);
 769                 if (error) {
 770                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 771                         goto out_unlock_mutex;
 772                 }
 773         }
 774         xfs_iunlock(xip, XFS_ILOCK_EXCL);
 775
 776         /*
 777          * If we're writing the file then make sure to clear the
 778          * setuid and setgid bits if the process is not being run
 779          * by root.  This keeps people from modifying setuid and
 780          * setgid binaries.
 781          */
 782
 783         if (((xip->i_d.di_mode & S_ISUID) ||
 784             ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
 785                 (S_ISGID | S_IXGRP))) &&
 786              !capable(CAP_FSETID)) {
 787                 error = xfs_write_clear_setuid(xip);
 788                 if (likely(!error))
 789                         error = -remove_suid(file->f_dentry);
 790                 if (unlikely(error)) {
 791                         xfs_iunlock(xip, iolock);
 792                         goto out_unlock_mutex;
 793                 }
 794         }
 795
 796 retry:
 797         /* We can write back this queue in page reclaim */
 798         current->backing_dev_info = mapping->backing_dev_info;
 799
 800         if ((ioflags & IO_ISDIRECT)) {
 801                 if (need_flush) {
 802                         xfs_inval_cached_trace(io, pos, -1,
 803                                         ctooff(offtoct(pos)), -1);
 804                         bhv_vop_flushinval_pages(vp, ctooff(offtoct(pos)),
 805                                         -1, FI_REMAPF_LOCKED);
 806                 }
 807
 808                 if (need_i_mutex) {
 809                         /* demote the lock now the cached pages are gone */
 810                         XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
 811                         mutex_unlock(&inode->i_mutex);
 812
 813                         iolock = XFS_IOLOCK_SHARED;
 814                         locktype = VRWLOCK_WRITE_DIRECT;
 815                         need_i_mutex = 0;
 816                 }
 817
 818                 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
 819                                 *offset, ioflags);
 820                 ret = generic_file_direct_write(iocb, iovp,
 821                                 &segs, pos, offset, count, ocount);
 822
 823                 /*
 824                  * direct-io write to a hole: fall through to buffered I/O
 825                  * for completing the rest of the request.
 826                  */
 827                 if (ret >= 0 && ret != count) {
 828                         XFS_STATS_ADD(xs_write_bytes, ret);
 829
 830                         pos += ret;
 831                         count -= ret;
 832
 833                         need_i_mutex = 1;
 834                         ioflags &= ~IO_ISDIRECT;
 835                         xfs_iunlock(xip, iolock);
 836                         goto relock;
 837                 }
 838         } else {
 839                 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
 840                                 *offset, ioflags);
 841                 ret = generic_file_buffered_write(iocb, iovp, segs,
 842                                 pos, offset, count, ret);
 843         }
 844
 845         current->backing_dev_info = NULL;
 846
 847         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 848                 ret = wait_on_sync_kiocb(iocb);
 849
 850         if ((ret == -ENOSPC) &&
 851             DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
 852             !(ioflags & IO_INVIS)) {
 853
 854                 xfs_rwunlock(bdp, locktype);
 855                 if (need_i_mutex)
 856                         mutex_unlock(&inode->i_mutex);
 857                 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
 858                                 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
 859                                 0, 0, 0); /* Delay flag intentionally  unused */
 860                 if (error)
 861                         goto out_nounlocks;
 862                 if (need_i_mutex)
 863                         mutex_lock(&inode->i_mutex);
 864                 xfs_rwlock(bdp, locktype);
 865                 pos = xip->i_d.di_size;
 866                 ret = 0;
 867                 goto retry;
 868         }
 869
 870         isize = i_size_read(inode);
 871         if (unlikely(ret < 0 && ret != -EFAULT && *offset > isize))
 872                 *offset = isize;
 873
 874         if (*offset > xip->i_d.di_size) {
 875                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 876                 if (*offset > xip->i_d.di_size) {
 877                         xip->i_d.di_size = *offset;
 878                         i_size_write(inode, *offset);
 879                         xip->i_update_core = 1;
 880                         xip->i_update_size = 1;
 881                 }
 882                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 883         }
 884
 885         error = -ret;
 886         if (ret <= 0)
 887                 goto out_unlock_internal;
 888
 889         XFS_STATS_ADD(xs_write_bytes, ret);
 890
 891         /* Handle various SYNC-type writes */
 892         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
 893                 error = xfs_write_sync_logforce(mp, xip);
 894                 if (error)
 895                         goto out_unlock_internal;
 896
 897                 xfs_rwunlock(bdp, locktype);
 898                 if (need_i_mutex)
 899                         mutex_unlock(&inode->i_mutex);
 900
 901                 error = sync_page_range(inode, mapping, pos, ret);
 902                 if (!error)
 903                         error = ret;
 904                 return error;
 905         }
 906
 907  out_unlock_internal:
 908         xfs_rwunlock(bdp, locktype);
 909  out_unlock_mutex:
 910         if (need_i_mutex)
 911                 mutex_unlock(&inode->i_mutex);
 912  out_nounlocks:
 913         return -error;
 914 }
 915
 916 /*
 917  * All xfs metadata buffers except log state machine buffers
 918  * get this attached as their b_bdstrat callback function.
 919  * This is so that we can catch a buffer
 920  * after prematurely unpinning it to forcibly shutdown the filesystem.
 921  */
 922 int
 923 xfs_bdstrat_cb(struct xfs_buf *bp)
 924 {
 925         xfs_mount_t     *mp;
 926
 927         mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
 928         if (!XFS_FORCED_SHUTDOWN(mp)) {
 929                 xfs_buf_iorequest(bp);
 930                 return 0;
 931         } else {
 932                 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
 933                 /*
 934                  * Metadata write that didn't get logged but
 935                  * written delayed anyway. These aren't associated
 936                  * with a transaction, and can be ignored.
 937                  */
 938                 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
 939                     (XFS_BUF_ISREAD(bp)) == 0)
 940                         return (xfs_bioerror_relse(bp));
 941                 else
 942                         return (xfs_bioerror(bp));
 943         }
 944 }
 945
 946
 947 int
 948 xfs_bmap(bhv_desc_t     *bdp,
 949         xfs_off_t       offset,
 950         ssize_t         count,
 951         int             flags,
 952         xfs_iomap_t     *iomapp,
 953         int             *niomaps)
 954 {
 955         xfs_inode_t     *ip = XFS_BHVTOI(bdp);
 956         xfs_iocore_t    *io = &ip->i_iocore;
 957
 958         ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
 959         ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
 960                ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
 961
 962         return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
 963 }
 964
 965 /*
 966  * Wrapper around bdstrat so that we can stop data
 967  * from going to disk in case we are shutting down the filesystem.
 968  * Typically user data goes thru this path; one of the exceptions
 969  * is the superblock.
 970  */
 971 int
 972 xfsbdstrat(
 973         struct xfs_mount        *mp,
 974         struct xfs_buf          *bp)
 975 {
 976         ASSERT(mp);
 977         if (!XFS_FORCED_SHUTDOWN(mp)) {
 978                 /* Grio redirection would go here
 979                  * if (XFS_BUF_IS_GRIO(bp)) {
 980                  */
 981
 982                 xfs_buf_iorequest(bp);
 983                 return 0;
 984         }
 985
 986         xfs_buftrace("XFSBDSTRAT IOERROR", bp);
 987         return (xfs_bioerror_relse(bp));
 988 }
 989
 990 /*
 991  * If the underlying (data/log/rt) device is readonly, there are some
 992  * operations that cannot proceed.
 993  */
 994 int
 995 xfs_dev_is_read_only(
 996         xfs_mount_t             *mp,
 997         char                    *message)
 998 {
 999         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1000             xfs_readonly_buftarg(mp->m_logdev_targp) ||
1001             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1002                 cmn_err(CE_NOTE,
1003                         "XFS: %s required on read-only device.", message);
1004                 cmn_err(CE_NOTE,
1005                         "XFS: write access unavailable, cannot proceed.");
1006                 return EROFS;
1007         }
1008         return 0;
1009 }