fs/xfs/linux-2.6/xfs_lrw.c

   1 /*
   2  * Copyright (c) 2000-2003 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32 /*
  33  *  fs/xfs/linux/xfs_lrw.c (Linux Read Write stuff)
  34  *
  35  */
  36
  37 #include "xfs.h"
  38
  39 #include "xfs_fs.h"
  40 #include "xfs_inum.h"
  41 #include "xfs_log.h"
  42 #include "xfs_trans.h"
  43 #include "xfs_sb.h"
  44 #include "xfs_ag.h"
  45 #include "xfs_dir.h"
  46 #include "xfs_dir2.h"
  47 #include "xfs_alloc.h"
  48 #include "xfs_dmapi.h"
  49 #include "xfs_quota.h"
  50 #include "xfs_mount.h"
  51 #include "xfs_alloc_btree.h"
  52 #include "xfs_bmap_btree.h"
  53 #include "xfs_ialloc_btree.h"
  54 #include "xfs_btree.h"
  55 #include "xfs_ialloc.h"
  56 #include "xfs_attr_sf.h"
  57 #include "xfs_dir_sf.h"
  58 #include "xfs_dir2_sf.h"
  59 #include "xfs_dinode.h"
  60 #include "xfs_inode.h"
  61 #include "xfs_bmap.h"
  62 #include "xfs_bit.h"
  63 #include "xfs_rtalloc.h"
  64 #include "xfs_error.h"
  65 #include "xfs_itable.h"
  66 #include "xfs_rw.h"
  67 #include "xfs_acl.h"
  68 #include "xfs_cap.h"
  69 #include "xfs_mac.h"
  70 #include "xfs_attr.h"
  71 #include "xfs_inode_item.h"
  72 #include "xfs_buf_item.h"
  73 #include "xfs_utils.h"
  74 #include "xfs_iomap.h"
  75
  76 #include <linux/capability.h>
  77 #include <linux/writeback.h>
  78
  79
  80 #if defined(XFS_RW_TRACE)
  81 void
  82 xfs_rw_enter_trace(
  83         int                     tag,
  84         xfs_iocore_t            *io,
  85         void                    *data,
  86         size_t                  segs,
  87         loff_t                  offset,
  88         int                     ioflags)
  89 {
  90         xfs_inode_t     *ip = XFS_IO_INODE(io);
  91
  92         if (ip->i_rwtrace == NULL)
  93                 return;
  94         ktrace_enter(ip->i_rwtrace,
  95                 (void *)(unsigned long)tag,
  96                 (void *)ip,
  97                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
  98                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
  99                 (void *)data,
 100                 (void *)((unsigned long)segs),
 101                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
 102                 (void *)((unsigned long)(offset & 0xffffffff)),
 103                 (void *)((unsigned long)ioflags),
 104                 (void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
 105                 (void *)((unsigned long)(io->io_new_size & 0xffffffff)),
 106                 (void *)NULL,
 107                 (void *)NULL,
 108                 (void *)NULL,
 109                 (void *)NULL,
 110                 (void *)NULL);
 111 }
 112
 113 void
 114 xfs_inval_cached_trace(
 115         xfs_iocore_t    *io,
 116         xfs_off_t       offset,
 117         xfs_off_t       len,
 118         xfs_off_t       first,
 119         xfs_off_t       last)
 120 {
 121         xfs_inode_t     *ip = XFS_IO_INODE(io);
 122
 123         if (ip->i_rwtrace == NULL)
 124                 return;
 125         ktrace_enter(ip->i_rwtrace,
 126                 (void *)(__psint_t)XFS_INVAL_CACHED,
 127                 (void *)ip,
 128                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
 129                 (void *)((unsigned long)(offset & 0xffffffff)),
 130                 (void *)((unsigned long)((len >> 32) & 0xffffffff)),
 131                 (void *)((unsigned long)(len & 0xffffffff)),
 132                 (void *)((unsigned long)((first >> 32) & 0xffffffff)),
 133                 (void *)((unsigned long)(first & 0xffffffff)),
 134                 (void *)((unsigned long)((last >> 32) & 0xffffffff)),
 135                 (void *)((unsigned long)(last & 0xffffffff)),
 136                 (void *)NULL,
 137                 (void *)NULL,
 138                 (void *)NULL,
 139                 (void *)NULL,
 140                 (void *)NULL,
 141                 (void *)NULL);
 142 }
 143 #endif
 144
 145 /*
 146  *      xfs_iozero
 147  *
 148  *      xfs_iozero clears the specified range of buffer supplied,
 149  *      and marks all the affected blocks as valid and modified.  If
 150  *      an affected block is not allocated, it will be allocated.  If
 151  *      an affected block is not completely overwritten, and is not
 152  *      valid before the operation, it will be read from disk before
 153  *      being partially zeroed.
 154  */
 155 STATIC int
 156 xfs_iozero(
 157         struct inode            *ip,    /* inode                        */
 158         loff_t                  pos,    /* offset in file               */
 159         size_t                  count,  /* size of data to zero         */
 160         loff_t                  end_size)       /* max file size to set */
 161 {
 162         unsigned                bytes;
 163         struct page             *page;
 164         struct address_space    *mapping;
 165         char                    *kaddr;
 166         int                     status;
 167
 168         mapping = ip->i_mapping;
 169         do {
 170                 unsigned long index, offset;
 171
 172                 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
 173                 index = pos >> PAGE_CACHE_SHIFT;
 174                 bytes = PAGE_CACHE_SIZE - offset;
 175                 if (bytes > count)
 176                         bytes = count;
 177
 178                 status = -ENOMEM;
 179                 page = grab_cache_page(mapping, index);
 180                 if (!page)
 181                         break;
 182
 183                 kaddr = kmap(page);
 184                 status = mapping->a_ops->prepare_write(NULL, page, offset,
 185                                                         offset + bytes);
 186                 if (status) {
 187                         goto unlock;
 188                 }
 189
 190                 memset((void *) (kaddr + offset), 0, bytes);
 191                 flush_dcache_page(page);
 192                 status = mapping->a_ops->commit_write(NULL, page, offset,
 193                                                         offset + bytes);
 194                 if (!status) {
 195                         pos += bytes;
 196                         count -= bytes;
 197                         if (pos > i_size_read(ip))
 198                                 i_size_write(ip, pos < end_size ? pos : end_size);
 199                 }
 200
 201 unlock:
 202                 kunmap(page);
 203                 unlock_page(page);
 204                 page_cache_release(page);
 205                 if (status)
 206                         break;
 207         } while (count);
 208
 209         return (-status);
 210 }
 211
 212 /*
 213  * xfs_inval_cached_pages
 214  *
 215  * This routine is responsible for keeping direct I/O and buffered I/O
 216  * somewhat coherent.  From here we make sure that we're at least
 217  * temporarily holding the inode I/O lock exclusively and then call
 218  * the page cache to flush and invalidate any cached pages.  If there
 219  * are no cached pages this routine will be very quick.
 220  */
 221 void
 222 xfs_inval_cached_pages(
 223         vnode_t         *vp,
 224         xfs_iocore_t    *io,
 225         xfs_off_t       offset,
 226         int             write,
 227         int             relock)
 228 {
 229         if (VN_CACHED(vp)) {
 230                 xfs_inval_cached_trace(io, offset, -1, ctooff(offtoct(offset)), -1);
 231                 VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(offset)), -1, FI_REMAPF_LOCKED);
 232         }
 233
 234 }
 235
 236 ssize_t                 /* bytes read, or (-)  error */
 237 xfs_read(
 238         bhv_desc_t              *bdp,
 239         struct kiocb            *iocb,
 240         const struct iovec      *iovp,
 241         unsigned int            segs,
 242         loff_t                  *offset,
 243         int                     ioflags,
 244         cred_t                  *credp)
 245 {
 246         struct file             *file = iocb->ki_filp;
 247         struct inode            *inode = file->f_mapping->host;
 248         size_t                  size = 0;
 249         ssize_t                 ret;
 250         xfs_fsize_t             n;
 251         xfs_inode_t             *ip;
 252         xfs_mount_t             *mp;
 253         vnode_t                 *vp;
 254         unsigned long           seg;
 255
 256         ip = XFS_BHVTOI(bdp);
 257         vp = BHV_TO_VNODE(bdp);
 258         mp = ip->i_mount;
 259
 260         XFS_STATS_INC(xs_read_calls);
 261
 262         /* START copy & waste from filemap.c */
 263         for (seg = 0; seg < segs; seg++) {
 264                 const struct iovec *iv = &iovp[seg];
 265
 266                 /*
 267                  * If any segment has a negative length, or the cumulative
 268                  * length ever wraps negative then return -EINVAL.
 269                  */
 270                 size += iv->iov_len;
 271                 if (unlikely((ssize_t)(size|iv->iov_len) < 0))
 272                         return XFS_ERROR(-EINVAL);
 273         }
 274         /* END copy & waste from filemap.c */
 275
 276         if (unlikely(ioflags & IO_ISDIRECT)) {
 277                 xfs_buftarg_t   *target =
 278                         (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 279                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 280                 if ((*offset & target->pbr_smask) ||
 281                     (size & target->pbr_smask)) {
 282                         if (*offset == ip->i_d.di_size) {
 283                                 return (0);
 284                         }
 285                         return -XFS_ERROR(EINVAL);
 286                 }
 287         }
 288
 289         n = XFS_MAXIOFFSET(mp) - *offset;
 290         if ((n <= 0) || (size == 0))
 291                 return 0;
 292
 293         if (n < size)
 294                 size = n;
 295
 296         if (XFS_FORCED_SHUTDOWN(mp)) {
 297                 return -EIO;
 298         }
 299
 300         if (unlikely(ioflags & IO_ISDIRECT))
 301                 down(&inode->i_sem);
 302         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 303
 304         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
 305             !(ioflags & IO_INVIS)) {
 306                 vrwlock_t locktype = VRWLOCK_READ;
 307
 308                 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
 309                                         BHV_TO_VNODE(bdp), *offset, size,
 310                                         FILP_DELAY_FLAG(file), &locktype);
 311                 if (ret) {
 312                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 313                         goto unlock_isem;
 314                 }
 315         }
 316
 317         xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
 318                                 (void *)iovp, segs, *offset, ioflags);
 319         ret = __generic_file_aio_read(iocb, iovp, segs, offset);
 320         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 321                 ret = wait_on_sync_kiocb(iocb);
 322         if (ret > 0)
 323                 XFS_STATS_ADD(xs_read_bytes, ret);
 324
 325         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 326
 327         if (likely(!(ioflags & IO_INVIS)))
 328                 xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
 329
 330 unlock_isem:
 331         if (unlikely(ioflags & IO_ISDIRECT))
 332                 up(&inode->i_sem);
 333         return ret;
 334 }
 335
 336 ssize_t
 337 xfs_sendfile(
 338         bhv_desc_t              *bdp,
 339         struct file             *filp,
 340         loff_t                  *offset,
 341         int                     ioflags,
 342         size_t                  count,
 343         read_actor_t            actor,
 344         void                    *target,
 345         cred_t                  *credp)
 346 {
 347         ssize_t                 ret;
 348         xfs_fsize_t             n;
 349         xfs_inode_t             *ip;
 350         xfs_mount_t             *mp;
 351         vnode_t                 *vp;
 352
 353         ip = XFS_BHVTOI(bdp);
 354         vp = BHV_TO_VNODE(bdp);
 355         mp = ip->i_mount;
 356
 357         XFS_STATS_INC(xs_read_calls);
 358
 359         n = XFS_MAXIOFFSET(mp) - *offset;
 360         if ((n <= 0) || (count == 0))
 361                 return 0;
 362
 363         if (n < count)
 364                 count = n;
 365
 366         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 367                 return -EIO;
 368
 369         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 370
 371         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
 372             (!(ioflags & IO_INVIS))) {
 373                 vrwlock_t locktype = VRWLOCK_READ;
 374                 int error;
 375
 376                 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp), *offset, count,
 377                                       FILP_DELAY_FLAG(filp), &locktype);
 378                 if (error) {
 379                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 380                         return -error;
 381                 }
 382         }
 383         xfs_rw_enter_trace(XFS_SENDFILE_ENTER, &ip->i_iocore,
 384                    (void *)(unsigned long)target, count, *offset, ioflags);
 385         ret = generic_file_sendfile(filp, offset, count, actor, target);
 386
 387         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 388
 389         if (ret > 0)
 390                 XFS_STATS_ADD(xs_read_bytes, ret);
 391
 392         if (likely(!(ioflags & IO_INVIS)))
 393                 xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
 394
 395         return ret;
 396 }
 397
 398 /*
 399  * This routine is called to handle zeroing any space in the last
 400  * block of the file that is beyond the EOF.  We do this since the
 401  * size is being increased without writing anything to that block
 402  * and we don't want anyone to read the garbage on the disk.
 403  */
 404 STATIC int                              /* error (positive) */
 405 xfs_zero_last_block(
 406         struct inode    *ip,
 407         xfs_iocore_t    *io,
 408         xfs_off_t       offset,
 409         xfs_fsize_t     isize,
 410         xfs_fsize_t     end_size)
 411 {
 412         xfs_fileoff_t   last_fsb;
 413         xfs_mount_t     *mp;
 414         int             nimaps;
 415         int             zero_offset;
 416         int             zero_len;
 417         int             isize_fsb_offset;
 418         int             error = 0;
 419         xfs_bmbt_irec_t imap;
 420         loff_t          loff;
 421         size_t          lsize;
 422
 423         ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
 424         ASSERT(offset > isize);
 425
 426         mp = io->io_mount;
 427
 428         isize_fsb_offset = XFS_B_FSB_OFFSET(mp, isize);
 429         if (isize_fsb_offset == 0) {
 430                 /*
 431                  * There are no extra bytes in the last block on disk to
 432                  * zero, so return.
 433                  */
 434                 return 0;
 435         }
 436
 437         last_fsb = XFS_B_TO_FSBT(mp, isize);
 438         nimaps = 1;
 439         error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
 440                           &nimaps, NULL);
 441         if (error) {
 442                 return error;
 443         }
 444         ASSERT(nimaps > 0);
 445         /*
 446          * If the block underlying isize is just a hole, then there
 447          * is nothing to zero.
 448          */
 449         if (imap.br_startblock == HOLESTARTBLOCK) {
 450                 return 0;
 451         }
 452         /*
 453          * Zero the part of the last block beyond the EOF, and write it
 454          * out sync.  We need to drop the ilock while we do this so we
 455          * don't deadlock when the buffer cache calls back to us.
 456          */
 457         XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
 458         loff = XFS_FSB_TO_B(mp, last_fsb);
 459         lsize = XFS_FSB_TO_B(mp, 1);
 460
 461         zero_offset = isize_fsb_offset;
 462         zero_len = mp->m_sb.sb_blocksize - isize_fsb_offset;
 463
 464         error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
 465
 466         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 467         ASSERT(error >= 0);
 468         return error;
 469 }
 470
 471 /*
 472  * Zero any on disk space between the current EOF and the new,
 473  * larger EOF.  This handles the normal case of zeroing the remainder
 474  * of the last block in the file and the unusual case of zeroing blocks
 475  * out beyond the size of the file.  This second case only happens
 476  * with fixed size extents and when the system crashes before the inode
 477  * size was updated but after blocks were allocated.  If fill is set,
 478  * then any holes in the range are filled and zeroed.  If not, the holes
 479  * are left alone as holes.
 480  */
 481
 482 int                                     /* error (positive) */
 483 xfs_zero_eof(
 484         vnode_t         *vp,
 485         xfs_iocore_t    *io,
 486         xfs_off_t       offset,         /* starting I/O offset */
 487         xfs_fsize_t     isize,          /* current inode size */
 488         xfs_fsize_t     end_size)       /* terminal inode size */
 489 {
 490         struct inode    *ip = LINVFS_GET_IP(vp);
 491         xfs_fileoff_t   start_zero_fsb;
 492         xfs_fileoff_t   end_zero_fsb;
 493         xfs_fileoff_t   prev_zero_fsb;
 494         xfs_fileoff_t   zero_count_fsb;
 495         xfs_fileoff_t   last_fsb;
 496         xfs_extlen_t    buf_len_fsb;
 497         xfs_extlen_t    prev_zero_count;
 498         xfs_mount_t     *mp;
 499         int             nimaps;
 500         int             error = 0;
 501         xfs_bmbt_irec_t imap;
 502         loff_t          loff;
 503         size_t          lsize;
 504
 505         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 506         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 507
 508         mp = io->io_mount;
 509
 510         /*
 511          * First handle zeroing the block on which isize resides.
 512          * We only zero a part of that block so it is handled specially.
 513          */
 514         error = xfs_zero_last_block(ip, io, offset, isize, end_size);
 515         if (error) {
 516                 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 517                 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 518                 return error;
 519         }
 520
 521         /*
 522          * Calculate the range between the new size and the old
 523          * where blocks needing to be zeroed may exist.  To get the
 524          * block where the last byte in the file currently resides,
 525          * we need to subtract one from the size and truncate back
 526          * to a block boundary.  We subtract 1 in case the size is
 527          * exactly on a block boundary.
 528          */
 529         last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
 530         start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
 531         end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
 532         ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
 533         if (last_fsb == end_zero_fsb) {
 534                 /*
 535                  * The size was only incremented on its last block.
 536                  * We took care of that above, so just return.
 537                  */
 538                 return 0;
 539         }
 540
 541         ASSERT(start_zero_fsb <= end_zero_fsb);
 542         prev_zero_fsb = NULLFILEOFF;
 543         prev_zero_count = 0;
 544         while (start_zero_fsb <= end_zero_fsb) {
 545                 nimaps = 1;
 546                 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
 547                 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
 548                                   0, NULL, 0, &imap, &nimaps, NULL);
 549                 if (error) {
 550                         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 551                         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 552                         return error;
 553                 }
 554                 ASSERT(nimaps > 0);
 555
 556                 if (imap.br_state == XFS_EXT_UNWRITTEN ||
 557                     imap.br_startblock == HOLESTARTBLOCK) {
 558                         /*
 559                          * This loop handles initializing pages that were
 560                          * partially initialized by the code below this
 561                          * loop. It basically zeroes the part of the page
 562                          * that sits on a hole and sets the page as P_HOLE
 563                          * and calls remapf if it is a mapped file.
 564                          */
 565                         prev_zero_fsb = NULLFILEOFF;
 566                         prev_zero_count = 0;
 567                         start_zero_fsb = imap.br_startoff +
 568                                          imap.br_blockcount;
 569                         ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 570                         continue;
 571                 }
 572
 573                 /*
 574                  * There are blocks in the range requested.
 575                  * Zero them a single write at a time.  We actually
 576                  * don't zero the entire range returned if it is
 577                  * too big and simply loop around to get the rest.
 578                  * That is not the most efficient thing to do, but it
 579                  * is simple and this path should not be exercised often.
 580                  */
 581                 buf_len_fsb = XFS_FILBLKS_MIN(imap.br_blockcount,
 582                                               mp->m_writeio_blocks << 8);
 583                 /*
 584                  * Drop the inode lock while we're doing the I/O.
 585                  * We'll still have the iolock to protect us.
 586                  */
 587                 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 588
 589                 loff = XFS_FSB_TO_B(mp, start_zero_fsb);
 590                 lsize = XFS_FSB_TO_B(mp, buf_len_fsb);
 591
 592                 error = xfs_iozero(ip, loff, lsize, end_size);
 593
 594                 if (error) {
 595                         goto out_lock;
 596                 }
 597
 598                 prev_zero_fsb = start_zero_fsb;
 599                 prev_zero_count = buf_len_fsb;
 600                 start_zero_fsb = imap.br_startoff + buf_len_fsb;
 601                 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 602
 603                 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 604         }
 605
 606         return 0;
 607
 608 out_lock:
 609
 610         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 611         ASSERT(error >= 0);
 612         return error;
 613 }
 614
 615 ssize_t                         /* bytes written, or (-) error */
 616 xfs_write(
 617         bhv_desc_t              *bdp,
 618         struct kiocb            *iocb,
 619         const struct iovec      *iovp,
 620         unsigned int            nsegs,
 621         loff_t                  *offset,
 622         int                     ioflags,
 623         cred_t                  *credp)
 624 {
 625         struct file             *file = iocb->ki_filp;
 626         struct address_space    *mapping = file->f_mapping;
 627         struct inode            *inode = mapping->host;
 628         unsigned long           segs = nsegs;
 629         xfs_inode_t             *xip;
 630         xfs_mount_t             *mp;
 631         ssize_t                 ret = 0, error = 0;
 632         xfs_fsize_t             isize, new_size;
 633         xfs_iocore_t            *io;
 634         vnode_t                 *vp;
 635         unsigned long           seg;
 636         int                     iolock;
 637         int                     eventsent = 0;
 638         vrwlock_t               locktype;
 639         size_t                  ocount = 0, count;
 640         loff_t                  pos;
 641         int                     need_isem = 1, need_flush = 0;
 642
 643         XFS_STATS_INC(xs_write_calls);
 644
 645         vp = BHV_TO_VNODE(bdp);
 646         xip = XFS_BHVTOI(bdp);
 647
 648         for (seg = 0; seg < segs; seg++) {
 649                 const struct iovec *iv = &iovp[seg];
 650
 651                 /*
 652                  * If any segment has a negative length, or the cumulative
 653                  * length ever wraps negative then return -EINVAL.
 654                  */
 655                 ocount += iv->iov_len;
 656                 if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
 657                         return -EINVAL;
 658                 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
 659                         continue;
 660                 if (seg == 0)
 661                         return -EFAULT;
 662                 segs = seg;
 663                 ocount -= iv->iov_len;  /* This segment is no good */
 664                 break;
 665         }
 666
 667         count = ocount;
 668         pos = *offset;
 669
 670         if (count == 0)
 671                 return 0;
 672
 673         io = &xip->i_iocore;
 674         mp = io->io_mount;
 675
 676         if (XFS_FORCED_SHUTDOWN(mp))
 677                 return -EIO;
 678
 679         fs_check_frozen(vp->v_vfsp, SB_FREEZE_WRITE);
 680
 681         if (ioflags & IO_ISDIRECT) {
 682                 xfs_buftarg_t   *target =
 683                         (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 684                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 685
 686                 if ((pos & target->pbr_smask) || (count & target->pbr_smask))
 687                         return XFS_ERROR(-EINVAL);
 688
 689                 if (!VN_CACHED(vp) && pos < i_size_read(inode))
 690                         need_isem = 0;
 691
 692                 if (VN_CACHED(vp))
 693                         need_flush = 1;
 694         }
 695
 696 relock:
 697         if (need_isem) {
 698                 iolock = XFS_IOLOCK_EXCL;
 699                 locktype = VRWLOCK_WRITE;
 700
 701                 down(&inode->i_sem);
 702         } else {
 703                 iolock = XFS_IOLOCK_SHARED;
 704                 locktype = VRWLOCK_WRITE_DIRECT;
 705         }
 706
 707         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
 708
 709         isize = i_size_read(inode);
 710
 711         if (file->f_flags & O_APPEND)
 712                 *offset = isize;
 713
 714 start:
 715         error = -generic_write_checks(file, &pos, &count,
 716                                         S_ISBLK(inode->i_mode));
 717         if (error) {
 718                 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 719                 goto out_unlock_isem;
 720         }
 721
 722         new_size = pos + count;
 723         if (new_size > isize)
 724                 io->io_new_size = new_size;
 725
 726         if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
 727             !(ioflags & IO_INVIS) && !eventsent)) {
 728                 loff_t          savedsize = pos;
 729                 int             dmflags = FILP_DELAY_FLAG(file);
 730
 731                 if (need_isem)
 732                         dmflags |= DM_FLAGS_ISEM;
 733
 734                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 735                 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
 736                                       pos, count,
 737                                       dmflags, &locktype);
 738                 if (error) {
 739                         xfs_iunlock(xip, iolock);
 740                         goto out_unlock_isem;
 741                 }
 742                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 743                 eventsent = 1;
 744
 745                 /*
 746                  * The iolock was dropped and reaquired in XFS_SEND_DATA
 747                  * so we have to recheck the size when appending.
 748                  * We will only "goto start;" once, since having sent the
 749                  * event prevents another call to XFS_SEND_DATA, which is
 750                  * what allows the size to change in the first place.
 751                  */
 752                 if ((file->f_flags & O_APPEND) && savedsize != isize) {
 753                         pos = isize = xip->i_d.di_size;
 754                         goto start;
 755                 }
 756         }
 757
 758         /*
 759          * On Linux, generic_file_write updates the times even if
 760          * no data is copied in so long as the write had a size.
 761          *
 762          * We must update xfs' times since revalidate will overcopy xfs.
 763          */
 764         if (!(ioflags & IO_INVIS)) {
 765                 xfs_ichgtime(xip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 766                 inode_update_time(inode, 1);
 767         }
 768
 769         /*
 770          * If the offset is beyond the size of the file, we have a couple
 771          * of things to do. First, if there is already space allocated
 772          * we need to either create holes or zero the disk or ...
 773          *
 774          * If there is a page where the previous size lands, we need
 775          * to zero it out up to the new size.
 776          */
 777
 778         if (pos > isize) {
 779                 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
 780                                         isize, pos + count);
 781                 if (error) {
 782                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 783                         goto out_unlock_isem;
 784                 }
 785         }
 786         xfs_iunlock(xip, XFS_ILOCK_EXCL);
 787
 788         /*
 789          * If we're writing the file then make sure to clear the
 790          * setuid and setgid bits if the process is not being run
 791          * by root.  This keeps people from modifying setuid and
 792          * setgid binaries.
 793          */
 794
 795         if (((xip->i_d.di_mode & S_ISUID) ||
 796             ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
 797                 (S_ISGID | S_IXGRP))) &&
 798              !capable(CAP_FSETID)) {
 799                 error = xfs_write_clear_setuid(xip);
 800                 if (likely(!error))
 801                         error = -remove_suid(file->f_dentry);
 802                 if (unlikely(error)) {
 803                         xfs_iunlock(xip, iolock);
 804                         goto out_unlock_isem;
 805                 }
 806         }
 807
 808 retry:
 809         /* We can write back this queue in page reclaim */
 810         current->backing_dev_info = mapping->backing_dev_info;
 811
 812         if ((ioflags & IO_ISDIRECT)) {
 813                 if (need_flush) {
 814                         xfs_inval_cached_trace(io, pos, -1,
 815                                         ctooff(offtoct(pos)), -1);
 816                         VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(pos)),
 817                                         -1, FI_REMAPF_LOCKED);
 818                 }
 819
 820                 if (need_isem) {
 821                         /* demote the lock now the cached pages are gone */
 822                         XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
 823                         up(&inode->i_sem);
 824
 825                         iolock = XFS_IOLOCK_SHARED;
 826                         locktype = VRWLOCK_WRITE_DIRECT;
 827                         need_isem = 0;
 828                 }
 829
 830                 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
 831                                 *offset, ioflags);
 832                 ret = generic_file_direct_write(iocb, iovp,
 833                                 &segs, pos, offset, count, ocount);
 834
 835                 /*
 836                  * direct-io write to a hole: fall through to buffered I/O
 837                  * for completing the rest of the request.
 838                  */
 839                 if (ret >= 0 && ret != count) {
 840                         XFS_STATS_ADD(xs_write_bytes, ret);
 841
 842                         pos += ret;
 843                         count -= ret;
 844
 845                         need_isem = 1;
 846                         ioflags &= ~IO_ISDIRECT;
 847                         xfs_iunlock(xip, iolock);
 848                         goto relock;
 849                 }
 850         } else {
 851                 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
 852                                 *offset, ioflags);
 853                 ret = generic_file_buffered_write(iocb, iovp, segs,
 854                                 pos, offset, count, ret);
 855         }
 856
 857         current->backing_dev_info = NULL;
 858
 859         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 860                 ret = wait_on_sync_kiocb(iocb);
 861
 862         if ((ret == -ENOSPC) &&
 863             DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
 864             !(ioflags & IO_INVIS)) {
 865
 866                 xfs_rwunlock(bdp, locktype);
 867                 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
 868                                 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
 869                                 0, 0, 0); /* Delay flag intentionally  unused */
 870                 if (error)
 871                         goto out_unlock_isem;
 872                 xfs_rwlock(bdp, locktype);
 873                 pos = xip->i_d.di_size;
 874                 ret = 0;
 875                 goto retry;
 876         }
 877
 878         if (*offset > xip->i_d.di_size) {
 879                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 880                 if (*offset > xip->i_d.di_size) {
 881                         xip->i_d.di_size = *offset;
 882                         i_size_write(inode, *offset);
 883                         xip->i_update_core = 1;
 884                         xip->i_update_size = 1;
 885                 }
 886                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 887         }
 888
 889         error = -ret;
 890         if (ret <= 0)
 891                 goto out_unlock_internal;
 892
 893         XFS_STATS_ADD(xs_write_bytes, ret);
 894
 895         /* Handle various SYNC-type writes */
 896         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
 897                 /*
 898                  * If we're treating this as O_DSYNC and we have not updated the
 899                  * size, force the log.
 900                  */
 901                 if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
 902                     !(xip->i_update_size)) {
 903                         xfs_inode_log_item_t    *iip = xip->i_itemp;
 904
 905                         /*
 906                          * If an allocation transaction occurred
 907                          * without extending the size, then we have to force
 908                          * the log up the proper point to ensure that the
 909                          * allocation is permanent.  We can't count on
 910                          * the fact that buffered writes lock out direct I/O
 911                          * writes - the direct I/O write could have extended
 912                          * the size nontransactionally, then finished before
 913                          * we started.  xfs_write_file will think that the file
 914                          * didn't grow but the update isn't safe unless the
 915                          * size change is logged.
 916                          *
 917                          * Force the log if we've committed a transaction
 918                          * against the inode or if someone else has and
 919                          * the commit record hasn't gone to disk (e.g.
 920                          * the inode is pinned).  This guarantees that
 921                          * all changes affecting the inode are permanent
 922                          * when we return.
 923                          */
 924                         if (iip && iip->ili_last_lsn) {
 925                                 xfs_log_force(mp, iip->ili_last_lsn,
 926                                                 XFS_LOG_FORCE | XFS_LOG_SYNC);
 927                         } else if (xfs_ipincount(xip) > 0) {
 928                                 xfs_log_force(mp, (xfs_lsn_t)0,
 929                                                 XFS_LOG_FORCE | XFS_LOG_SYNC);
 930                         }
 931
 932                 } else {
 933                         xfs_trans_t     *tp;
 934
 935                         /*
 936                          * O_SYNC or O_DSYNC _with_ a size update are handled
 937                          * the same way.
 938                          *
 939                          * If the write was synchronous then we need to make
 940                          * sure that the inode modification time is permanent.
 941                          * We'll have updated the timestamp above, so here
 942                          * we use a synchronous transaction to log the inode.
 943                          * It's not fast, but it's necessary.
 944                          *
 945                          * If this a dsync write and the size got changed
 946                          * non-transactionally, then we need to ensure that
 947                          * the size change gets logged in a synchronous
 948                          * transaction.
 949                          */
 950
 951                         tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
 952                         if ((error = xfs_trans_reserve(tp, 0,
 953                                                       XFS_SWRITE_LOG_RES(mp),
 954                                                       0, 0, 0))) {
 955                                 /* Transaction reserve failed */
 956                                 xfs_trans_cancel(tp, 0);
 957                         } else {
 958                                 /* Transaction reserve successful */
 959                                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 960                                 xfs_trans_ijoin(tp, xip, XFS_ILOCK_EXCL);
 961                                 xfs_trans_ihold(tp, xip);
 962                                 xfs_trans_log_inode(tp, xip, XFS_ILOG_CORE);
 963                                 xfs_trans_set_sync(tp);
 964                                 error = xfs_trans_commit(tp, 0, NULL);
 965                                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 966                         }
 967                         if (error)
 968                                 goto out_unlock_internal;
 969                 }
 970
 971                 xfs_rwunlock(bdp, locktype);
 972                 if (need_isem)
 973                         up(&inode->i_sem);
 974
 975                 error = sync_page_range(inode, mapping, pos, ret);
 976                 if (!error)
 977                         error = ret;
 978                 return error;
 979         }
 980
 981  out_unlock_internal:
 982         xfs_rwunlock(bdp, locktype);
 983  out_unlock_isem:
 984         if (need_isem)
 985                 up(&inode->i_sem);
 986         return -error;
 987 }
 988
 989 /*
 990  * All xfs metadata buffers except log state machine buffers
 991  * get this attached as their b_bdstrat callback function.
 992  * This is so that we can catch a buffer
 993  * after prematurely unpinning it to forcibly shutdown the filesystem.
 994  */
 995 int
 996 xfs_bdstrat_cb(struct xfs_buf *bp)
 997 {
 998         xfs_mount_t     *mp;
 999
1000         mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
1001         if (!XFS_FORCED_SHUTDOWN(mp)) {
1002                 pagebuf_iorequest(bp);
1003                 return 0;
1004         } else {
1005                 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
1006                 /*
1007                  * Metadata write that didn't get logged but
1008                  * written delayed anyway. These aren't associated
1009                  * with a transaction, and can be ignored.
1010                  */
1011                 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
1012                     (XFS_BUF_ISREAD(bp)) == 0)
1013                         return (xfs_bioerror_relse(bp));
1014                 else
1015                         return (xfs_bioerror(bp));
1016         }
1017 }
1018
1019
1020 int
1021 xfs_bmap(bhv_desc_t     *bdp,
1022         xfs_off_t       offset,
1023         ssize_t         count,
1024         int             flags,
1025         xfs_iomap_t     *iomapp,
1026         int             *niomaps)
1027 {
1028         xfs_inode_t     *ip = XFS_BHVTOI(bdp);
1029         xfs_iocore_t    *io = &ip->i_iocore;
1030
1031         ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
1032         ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
1033                ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
1034
1035         return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
1036 }
1037
1038 /*
1039  * Wrapper around bdstrat so that we can stop data
1040  * from going to disk in case we are shutting down the filesystem.
1041  * Typically user data goes thru this path; one of the exceptions
1042  * is the superblock.
1043  */
1044 int
1045 xfsbdstrat(
1046         struct xfs_mount        *mp,
1047         struct xfs_buf          *bp)
1048 {
1049         ASSERT(mp);
1050         if (!XFS_FORCED_SHUTDOWN(mp)) {
1051                 /* Grio redirection would go here
1052                  * if (XFS_BUF_IS_GRIO(bp)) {
1053                  */
1054
1055                 pagebuf_iorequest(bp);
1056                 return 0;
1057         }
1058
1059         xfs_buftrace("XFSBDSTRAT IOERROR", bp);
1060         return (xfs_bioerror_relse(bp));
1061 }
1062
1063 /*
1064  * If the underlying (data/log/rt) device is readonly, there are some
1065  * operations that cannot proceed.
1066  */
1067 int
1068 xfs_dev_is_read_only(
1069         xfs_mount_t             *mp,
1070         char                    *message)
1071 {
1072         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1073             xfs_readonly_buftarg(mp->m_logdev_targp) ||
1074             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1075                 cmn_err(CE_NOTE,
1076                         "XFS: %s required on read-only device.", message);
1077                 cmn_err(CE_NOTE,
1078                         "XFS: write access unavailable, cannot proceed.");
1079                 return EROFS;
1080         }
1081         return 0;
1082 }