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 ssize_t                 /* bytes read, or (-)  error */
 213 xfs_read(
 214         bhv_desc_t              *bdp,
 215         struct kiocb            *iocb,
 216         const struct iovec      *iovp,
 217         unsigned int            segs,
 218         loff_t                  *offset,
 219         int                     ioflags,
 220         cred_t                  *credp)
 221 {
 222         struct file             *file = iocb->ki_filp;
 223         struct inode            *inode = file->f_mapping->host;
 224         size_t                  size = 0;
 225         ssize_t                 ret;
 226         xfs_fsize_t             n;
 227         xfs_inode_t             *ip;
 228         xfs_mount_t             *mp;
 229         vnode_t                 *vp;
 230         unsigned long           seg;
 231
 232         ip = XFS_BHVTOI(bdp);
 233         vp = BHV_TO_VNODE(bdp);
 234         mp = ip->i_mount;
 235
 236         XFS_STATS_INC(xs_read_calls);
 237
 238         /* START copy & waste from filemap.c */
 239         for (seg = 0; seg < segs; seg++) {
 240                 const struct iovec *iv = &iovp[seg];
 241
 242                 /*
 243                  * If any segment has a negative length, or the cumulative
 244                  * length ever wraps negative then return -EINVAL.
 245                  */
 246                 size += iv->iov_len;
 247                 if (unlikely((ssize_t)(size|iv->iov_len) < 0))
 248                         return XFS_ERROR(-EINVAL);
 249         }
 250         /* END copy & waste from filemap.c */
 251
 252         if (unlikely(ioflags & IO_ISDIRECT)) {
 253                 xfs_buftarg_t   *target =
 254                         (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 255                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 256                 if ((*offset & target->pbr_smask) ||
 257                     (size & target->pbr_smask)) {
 258                         if (*offset == ip->i_d.di_size) {
 259                                 return (0);
 260                         }
 261                         return -XFS_ERROR(EINVAL);
 262                 }
 263         }
 264
 265         n = XFS_MAXIOFFSET(mp) - *offset;
 266         if ((n <= 0) || (size == 0))
 267                 return 0;
 268
 269         if (n < size)
 270                 size = n;
 271
 272         if (XFS_FORCED_SHUTDOWN(mp)) {
 273                 return -EIO;
 274         }
 275
 276         if (unlikely(ioflags & IO_ISDIRECT))
 277                 down(&inode->i_sem);
 278         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 279
 280         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
 281             !(ioflags & IO_INVIS)) {
 282                 vrwlock_t locktype = VRWLOCK_READ;
 283                 int dmflags = FILP_DELAY_FLAG(file) | DM_SEM_FLAG_RD(ioflags);
 284
 285                 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
 286                                         BHV_TO_VNODE(bdp), *offset, size,
 287                                         dmflags, &locktype);
 288                 if (ret) {
 289                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 290                         goto unlock_isem;
 291                 }
 292         }
 293
 294         xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
 295                                 (void *)iovp, segs, *offset, ioflags);
 296         ret = __generic_file_aio_read(iocb, iovp, segs, offset);
 297         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 298                 ret = wait_on_sync_kiocb(iocb);
 299         if (ret > 0)
 300                 XFS_STATS_ADD(xs_read_bytes, ret);
 301
 302         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 303
 304         if (likely(!(ioflags & IO_INVIS)))
 305                 xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
 306
 307 unlock_isem:
 308         if (unlikely(ioflags & IO_ISDIRECT))
 309                 up(&inode->i_sem);
 310         return ret;
 311 }
 312
 313 ssize_t
 314 xfs_sendfile(
 315         bhv_desc_t              *bdp,
 316         struct file             *filp,
 317         loff_t                  *offset,
 318         int                     ioflags,
 319         size_t                  count,
 320         read_actor_t            actor,
 321         void                    *target,
 322         cred_t                  *credp)
 323 {
 324         ssize_t                 ret;
 325         xfs_fsize_t             n;
 326         xfs_inode_t             *ip;
 327         xfs_mount_t             *mp;
 328         vnode_t                 *vp;
 329
 330         ip = XFS_BHVTOI(bdp);
 331         vp = BHV_TO_VNODE(bdp);
 332         mp = ip->i_mount;
 333
 334         XFS_STATS_INC(xs_read_calls);
 335
 336         n = XFS_MAXIOFFSET(mp) - *offset;
 337         if ((n <= 0) || (count == 0))
 338                 return 0;
 339
 340         if (n < count)
 341                 count = n;
 342
 343         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 344                 return -EIO;
 345
 346         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 347
 348         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
 349             (!(ioflags & IO_INVIS))) {
 350                 vrwlock_t locktype = VRWLOCK_READ;
 351                 int error;
 352
 353                 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp), *offset, count,
 354                                       FILP_DELAY_FLAG(filp), &locktype);
 355                 if (error) {
 356                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 357                         return -error;
 358                 }
 359         }
 360         xfs_rw_enter_trace(XFS_SENDFILE_ENTER, &ip->i_iocore,
 361                    (void *)(unsigned long)target, count, *offset, ioflags);
 362         ret = generic_file_sendfile(filp, offset, count, actor, target);
 363
 364         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 365
 366         if (ret > 0)
 367                 XFS_STATS_ADD(xs_read_bytes, ret);
 368
 369         if (likely(!(ioflags & IO_INVIS)))
 370                 xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
 371
 372         return ret;
 373 }
 374
 375 /*
 376  * This routine is called to handle zeroing any space in the last
 377  * block of the file that is beyond the EOF.  We do this since the
 378  * size is being increased without writing anything to that block
 379  * and we don't want anyone to read the garbage on the disk.
 380  */
 381 STATIC int                              /* error (positive) */
 382 xfs_zero_last_block(
 383         struct inode    *ip,
 384         xfs_iocore_t    *io,
 385         xfs_off_t       offset,
 386         xfs_fsize_t     isize,
 387         xfs_fsize_t     end_size)
 388 {
 389         xfs_fileoff_t   last_fsb;
 390         xfs_mount_t     *mp;
 391         int             nimaps;
 392         int             zero_offset;
 393         int             zero_len;
 394         int             isize_fsb_offset;
 395         int             error = 0;
 396         xfs_bmbt_irec_t imap;
 397         loff_t          loff;
 398         size_t          lsize;
 399
 400         ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
 401         ASSERT(offset > isize);
 402
 403         mp = io->io_mount;
 404
 405         isize_fsb_offset = XFS_B_FSB_OFFSET(mp, isize);
 406         if (isize_fsb_offset == 0) {
 407                 /*
 408                  * There are no extra bytes in the last block on disk to
 409                  * zero, so return.
 410                  */
 411                 return 0;
 412         }
 413
 414         last_fsb = XFS_B_TO_FSBT(mp, isize);
 415         nimaps = 1;
 416         error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
 417                           &nimaps, NULL);
 418         if (error) {
 419                 return error;
 420         }
 421         ASSERT(nimaps > 0);
 422         /*
 423          * If the block underlying isize is just a hole, then there
 424          * is nothing to zero.
 425          */
 426         if (imap.br_startblock == HOLESTARTBLOCK) {
 427                 return 0;
 428         }
 429         /*
 430          * Zero the part of the last block beyond the EOF, and write it
 431          * out sync.  We need to drop the ilock while we do this so we
 432          * don't deadlock when the buffer cache calls back to us.
 433          */
 434         XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
 435         loff = XFS_FSB_TO_B(mp, last_fsb);
 436         lsize = XFS_FSB_TO_B(mp, 1);
 437
 438         zero_offset = isize_fsb_offset;
 439         zero_len = mp->m_sb.sb_blocksize - isize_fsb_offset;
 440
 441         error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
 442
 443         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 444         ASSERT(error >= 0);
 445         return error;
 446 }
 447
 448 /*
 449  * Zero any on disk space between the current EOF and the new,
 450  * larger EOF.  This handles the normal case of zeroing the remainder
 451  * of the last block in the file and the unusual case of zeroing blocks
 452  * out beyond the size of the file.  This second case only happens
 453  * with fixed size extents and when the system crashes before the inode
 454  * size was updated but after blocks were allocated.  If fill is set,
 455  * then any holes in the range are filled and zeroed.  If not, the holes
 456  * are left alone as holes.
 457  */
 458
 459 int                                     /* error (positive) */
 460 xfs_zero_eof(
 461         vnode_t         *vp,
 462         xfs_iocore_t    *io,
 463         xfs_off_t       offset,         /* starting I/O offset */
 464         xfs_fsize_t     isize,          /* current inode size */
 465         xfs_fsize_t     end_size)       /* terminal inode size */
 466 {
 467         struct inode    *ip = LINVFS_GET_IP(vp);
 468         xfs_fileoff_t   start_zero_fsb;
 469         xfs_fileoff_t   end_zero_fsb;
 470         xfs_fileoff_t   prev_zero_fsb;
 471         xfs_fileoff_t   zero_count_fsb;
 472         xfs_fileoff_t   last_fsb;
 473         xfs_extlen_t    buf_len_fsb;
 474         xfs_extlen_t    prev_zero_count;
 475         xfs_mount_t     *mp;
 476         int             nimaps;
 477         int             error = 0;
 478         xfs_bmbt_irec_t imap;
 479         loff_t          loff;
 480         size_t          lsize;
 481
 482         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 483         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 484
 485         mp = io->io_mount;
 486
 487         /*
 488          * First handle zeroing the block on which isize resides.
 489          * We only zero a part of that block so it is handled specially.
 490          */
 491         error = xfs_zero_last_block(ip, io, offset, isize, end_size);
 492         if (error) {
 493                 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 494                 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 495                 return error;
 496         }
 497
 498         /*
 499          * Calculate the range between the new size and the old
 500          * where blocks needing to be zeroed may exist.  To get the
 501          * block where the last byte in the file currently resides,
 502          * we need to subtract one from the size and truncate back
 503          * to a block boundary.  We subtract 1 in case the size is
 504          * exactly on a block boundary.
 505          */
 506         last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
 507         start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
 508         end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
 509         ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
 510         if (last_fsb == end_zero_fsb) {
 511                 /*
 512                  * The size was only incremented on its last block.
 513                  * We took care of that above, so just return.
 514                  */
 515                 return 0;
 516         }
 517
 518         ASSERT(start_zero_fsb <= end_zero_fsb);
 519         prev_zero_fsb = NULLFILEOFF;
 520         prev_zero_count = 0;
 521         while (start_zero_fsb <= end_zero_fsb) {
 522                 nimaps = 1;
 523                 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
 524                 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
 525                                   0, NULL, 0, &imap, &nimaps, NULL);
 526                 if (error) {
 527                         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
 528                         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
 529                         return error;
 530                 }
 531                 ASSERT(nimaps > 0);
 532
 533                 if (imap.br_state == XFS_EXT_UNWRITTEN ||
 534                     imap.br_startblock == HOLESTARTBLOCK) {
 535                         /*
 536                          * This loop handles initializing pages that were
 537                          * partially initialized by the code below this
 538                          * loop. It basically zeroes the part of the page
 539                          * that sits on a hole and sets the page as P_HOLE
 540                          * and calls remapf if it is a mapped file.
 541                          */
 542                         prev_zero_fsb = NULLFILEOFF;
 543                         prev_zero_count = 0;
 544                         start_zero_fsb = imap.br_startoff +
 545                                          imap.br_blockcount;
 546                         ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 547                         continue;
 548                 }
 549
 550                 /*
 551                  * There are blocks in the range requested.
 552                  * Zero them a single write at a time.  We actually
 553                  * don't zero the entire range returned if it is
 554                  * too big and simply loop around to get the rest.
 555                  * That is not the most efficient thing to do, but it
 556                  * is simple and this path should not be exercised often.
 557                  */
 558                 buf_len_fsb = XFS_FILBLKS_MIN(imap.br_blockcount,
 559                                               mp->m_writeio_blocks << 8);
 560                 /*
 561                  * Drop the inode lock while we're doing the I/O.
 562                  * We'll still have the iolock to protect us.
 563                  */
 564                 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 565
 566                 loff = XFS_FSB_TO_B(mp, start_zero_fsb);
 567                 lsize = XFS_FSB_TO_B(mp, buf_len_fsb);
 568
 569                 error = xfs_iozero(ip, loff, lsize, end_size);
 570
 571                 if (error) {
 572                         goto out_lock;
 573                 }
 574
 575                 prev_zero_fsb = start_zero_fsb;
 576                 prev_zero_count = buf_len_fsb;
 577                 start_zero_fsb = imap.br_startoff + buf_len_fsb;
 578                 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
 579
 580                 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 581         }
 582
 583         return 0;
 584
 585 out_lock:
 586
 587         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 588         ASSERT(error >= 0);
 589         return error;
 590 }
 591
 592 ssize_t                         /* bytes written, or (-) error */
 593 xfs_write(
 594         bhv_desc_t              *bdp,
 595         struct kiocb            *iocb,
 596         const struct iovec      *iovp,
 597         unsigned int            nsegs,
 598         loff_t                  *offset,
 599         int                     ioflags,
 600         cred_t                  *credp)
 601 {
 602         struct file             *file = iocb->ki_filp;
 603         struct address_space    *mapping = file->f_mapping;
 604         struct inode            *inode = mapping->host;
 605         unsigned long           segs = nsegs;
 606         xfs_inode_t             *xip;
 607         xfs_mount_t             *mp;
 608         ssize_t                 ret = 0, error = 0;
 609         xfs_fsize_t             isize, new_size;
 610         xfs_iocore_t            *io;
 611         vnode_t                 *vp;
 612         unsigned long           seg;
 613         int                     iolock;
 614         int                     eventsent = 0;
 615         vrwlock_t               locktype;
 616         size_t                  ocount = 0, count;
 617         loff_t                  pos;
 618         int                     need_isem = 1, need_flush = 0;
 619
 620         XFS_STATS_INC(xs_write_calls);
 621
 622         vp = BHV_TO_VNODE(bdp);
 623         xip = XFS_BHVTOI(bdp);
 624
 625         for (seg = 0; seg < segs; seg++) {
 626                 const struct iovec *iv = &iovp[seg];
 627
 628                 /*
 629                  * If any segment has a negative length, or the cumulative
 630                  * length ever wraps negative then return -EINVAL.
 631                  */
 632                 ocount += iv->iov_len;
 633                 if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
 634                         return -EINVAL;
 635                 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
 636                         continue;
 637                 if (seg == 0)
 638                         return -EFAULT;
 639                 segs = seg;
 640                 ocount -= iv->iov_len;  /* This segment is no good */
 641                 break;
 642         }
 643
 644         count = ocount;
 645         pos = *offset;
 646
 647         if (count == 0)
 648                 return 0;
 649
 650         io = &xip->i_iocore;
 651         mp = io->io_mount;
 652
 653         if (XFS_FORCED_SHUTDOWN(mp))
 654                 return -EIO;
 655
 656         fs_check_frozen(vp->v_vfsp, SB_FREEZE_WRITE);
 657
 658         if (ioflags & IO_ISDIRECT) {
 659                 xfs_buftarg_t   *target =
 660                         (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
 661                                 mp->m_rtdev_targp : mp->m_ddev_targp;
 662
 663                 if (ioflags & IO_ISAIO)
 664                         return XFS_ERROR(-ENOSYS);
 665
 666                 if ((pos & target->pbr_smask) || (count & target->pbr_smask))
 667                         return XFS_ERROR(-EINVAL);
 668
 669                 if (!VN_CACHED(vp) && pos < i_size_read(inode))
 670                         need_isem = 0;
 671
 672                 if (VN_CACHED(vp))
 673                         need_flush = 1;
 674         }
 675
 676 relock:
 677         if (need_isem) {
 678                 iolock = XFS_IOLOCK_EXCL;
 679                 locktype = VRWLOCK_WRITE;
 680
 681                 down(&inode->i_sem);
 682         } else {
 683                 iolock = XFS_IOLOCK_SHARED;
 684                 locktype = VRWLOCK_WRITE_DIRECT;
 685         }
 686
 687         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
 688
 689         isize = i_size_read(inode);
 690
 691         if (file->f_flags & O_APPEND)
 692                 *offset = isize;
 693
 694 start:
 695         error = -generic_write_checks(file, &pos, &count,
 696                                         S_ISBLK(inode->i_mode));
 697         if (error) {
 698                 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 699                 goto out_unlock_isem;
 700         }
 701
 702         new_size = pos + count;
 703         if (new_size > isize)
 704                 io->io_new_size = new_size;
 705
 706         if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
 707             !(ioflags & IO_INVIS) && !eventsent)) {
 708                 loff_t          savedsize = pos;
 709                 int             dmflags = FILP_DELAY_FLAG(file);
 710
 711                 if (need_isem)
 712                         dmflags |= DM_FLAGS_ISEM;
 713
 714                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 715                 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
 716                                       pos, count,
 717                                       dmflags, &locktype);
 718                 if (error) {
 719                         xfs_iunlock(xip, iolock);
 720                         goto out_unlock_isem;
 721                 }
 722                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 723                 eventsent = 1;
 724
 725                 /*
 726                  * The iolock was dropped and reaquired in XFS_SEND_DATA
 727                  * so we have to recheck the size when appending.
 728                  * We will only "goto start;" once, since having sent the
 729                  * event prevents another call to XFS_SEND_DATA, which is
 730                  * what allows the size to change in the first place.
 731                  */
 732                 if ((file->f_flags & O_APPEND) && savedsize != isize) {
 733                         pos = isize = xip->i_d.di_size;
 734                         goto start;
 735                 }
 736         }
 737
 738         /*
 739          * On Linux, generic_file_write updates the times even if
 740          * no data is copied in so long as the write had a size.
 741          *
 742          * We must update xfs' times since revalidate will overcopy xfs.
 743          */
 744         if (!(ioflags & IO_INVIS)) {
 745                 xfs_ichgtime(xip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 746                 inode_update_time(inode, 1);
 747         }
 748
 749         /*
 750          * If the offset is beyond the size of the file, we have a couple
 751          * of things to do. First, if there is already space allocated
 752          * we need to either create holes or zero the disk or ...
 753          *
 754          * If there is a page where the previous size lands, we need
 755          * to zero it out up to the new size.
 756          */
 757
 758         if (pos > isize) {
 759                 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
 760                                         isize, pos + count);
 761                 if (error) {
 762                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
 763                         goto out_unlock_isem;
 764                 }
 765         }
 766         xfs_iunlock(xip, XFS_ILOCK_EXCL);
 767
 768         /*
 769          * If we're writing the file then make sure to clear the
 770          * setuid and setgid bits if the process is not being run
 771          * by root.  This keeps people from modifying setuid and
 772          * setgid binaries.
 773          */
 774
 775         if (((xip->i_d.di_mode & S_ISUID) ||
 776             ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
 777                 (S_ISGID | S_IXGRP))) &&
 778              !capable(CAP_FSETID)) {
 779                 error = xfs_write_clear_setuid(xip);
 780                 if (likely(!error))
 781                         error = -remove_suid(file->f_dentry);
 782                 if (unlikely(error)) {
 783                         xfs_iunlock(xip, iolock);
 784                         goto out_unlock_isem;
 785                 }
 786         }
 787
 788 retry:
 789         /* We can write back this queue in page reclaim */
 790         current->backing_dev_info = mapping->backing_dev_info;
 791
 792         if ((ioflags & IO_ISDIRECT)) {
 793                 if (need_flush) {
 794                         xfs_inval_cached_trace(io, pos, -1,
 795                                         ctooff(offtoct(pos)), -1);
 796                         VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(pos)),
 797                                         -1, FI_REMAPF_LOCKED);
 798                 }
 799
 800                 if (need_isem) {
 801                         /* demote the lock now the cached pages are gone */
 802                         XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
 803                         up(&inode->i_sem);
 804
 805                         iolock = XFS_IOLOCK_SHARED;
 806                         locktype = VRWLOCK_WRITE_DIRECT;
 807                         need_isem = 0;
 808                 }
 809
 810                 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
 811                                 *offset, ioflags);
 812                 ret = generic_file_direct_write(iocb, iovp,
 813                                 &segs, pos, offset, count, ocount);
 814
 815                 /*
 816                  * direct-io write to a hole: fall through to buffered I/O
 817                  * for completing the rest of the request.
 818                  */
 819                 if (ret >= 0 && ret != count) {
 820                         XFS_STATS_ADD(xs_write_bytes, ret);
 821
 822                         pos += ret;
 823                         count -= ret;
 824
 825                         need_isem = 1;
 826                         ioflags &= ~IO_ISDIRECT;
 827                         xfs_iunlock(xip, iolock);
 828                         goto relock;
 829                 }
 830         } else {
 831                 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
 832                                 *offset, ioflags);
 833                 ret = generic_file_buffered_write(iocb, iovp, segs,
 834                                 pos, offset, count, ret);
 835         }
 836
 837         current->backing_dev_info = NULL;
 838
 839         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
 840                 ret = wait_on_sync_kiocb(iocb);
 841
 842         if ((ret == -ENOSPC) &&
 843             DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
 844             !(ioflags & IO_INVIS)) {
 845
 846                 xfs_rwunlock(bdp, locktype);
 847                 if (need_isem)
 848                         up(&inode->i_sem);
 849                 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
 850                                 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
 851                                 0, 0, 0); /* Delay flag intentionally  unused */
 852                 if (error)
 853                         goto out_nounlocks;
 854                 if (need_isem)
 855                         down(&inode->i_sem);
 856                 xfs_rwlock(bdp, locktype);
 857                 pos = xip->i_d.di_size;
 858                 ret = 0;
 859                 goto retry;
 860         }
 861
 862         if (*offset > xip->i_d.di_size) {
 863                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 864                 if (*offset > xip->i_d.di_size) {
 865                         xip->i_d.di_size = *offset;
 866                         i_size_write(inode, *offset);
 867                         xip->i_update_core = 1;
 868                         xip->i_update_size = 1;
 869                 }
 870                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 871         }
 872
 873         error = -ret;
 874         if (ret <= 0)
 875                 goto out_unlock_internal;
 876
 877         XFS_STATS_ADD(xs_write_bytes, ret);
 878
 879         /* Handle various SYNC-type writes */
 880         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
 881                 /*
 882                  * If we're treating this as O_DSYNC and we have not updated the
 883                  * size, force the log.
 884                  */
 885                 if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
 886                     !(xip->i_update_size)) {
 887                         xfs_inode_log_item_t    *iip = xip->i_itemp;
 888
 889                         /*
 890                          * If an allocation transaction occurred
 891                          * without extending the size, then we have to force
 892                          * the log up the proper point to ensure that the
 893                          * allocation is permanent.  We can't count on
 894                          * the fact that buffered writes lock out direct I/O
 895                          * writes - the direct I/O write could have extended
 896                          * the size nontransactionally, then finished before
 897                          * we started.  xfs_write_file will think that the file
 898                          * didn't grow but the update isn't safe unless the
 899                          * size change is logged.
 900                          *
 901                          * Force the log if we've committed a transaction
 902                          * against the inode or if someone else has and
 903                          * the commit record hasn't gone to disk (e.g.
 904                          * the inode is pinned).  This guarantees that
 905                          * all changes affecting the inode are permanent
 906                          * when we return.
 907                          */
 908                         if (iip && iip->ili_last_lsn) {
 909                                 xfs_log_force(mp, iip->ili_last_lsn,
 910                                                 XFS_LOG_FORCE | XFS_LOG_SYNC);
 911                         } else if (xfs_ipincount(xip) > 0) {
 912                                 xfs_log_force(mp, (xfs_lsn_t)0,
 913                                                 XFS_LOG_FORCE | XFS_LOG_SYNC);
 914                         }
 915
 916                 } else {
 917                         xfs_trans_t     *tp;
 918
 919                         /*
 920                          * O_SYNC or O_DSYNC _with_ a size update are handled
 921                          * the same way.
 922                          *
 923                          * If the write was synchronous then we need to make
 924                          * sure that the inode modification time is permanent.
 925                          * We'll have updated the timestamp above, so here
 926                          * we use a synchronous transaction to log the inode.
 927                          * It's not fast, but it's necessary.
 928                          *
 929                          * If this a dsync write and the size got changed
 930                          * non-transactionally, then we need to ensure that
 931                          * the size change gets logged in a synchronous
 932                          * transaction.
 933                          */
 934
 935                         tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
 936                         if ((error = xfs_trans_reserve(tp, 0,
 937                                                       XFS_SWRITE_LOG_RES(mp),
 938                                                       0, 0, 0))) {
 939                                 /* Transaction reserve failed */
 940                                 xfs_trans_cancel(tp, 0);
 941                         } else {
 942                                 /* Transaction reserve successful */
 943                                 xfs_ilock(xip, XFS_ILOCK_EXCL);
 944                                 xfs_trans_ijoin(tp, xip, XFS_ILOCK_EXCL);
 945                                 xfs_trans_ihold(tp, xip);
 946                                 xfs_trans_log_inode(tp, xip, XFS_ILOG_CORE);
 947                                 xfs_trans_set_sync(tp);
 948                                 error = xfs_trans_commit(tp, 0, NULL);
 949                                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
 950                         }
 951                         if (error)
 952                                 goto out_unlock_internal;
 953                 }
 954
 955                 xfs_rwunlock(bdp, locktype);
 956                 if (need_isem)
 957                         up(&inode->i_sem);
 958
 959                 error = sync_page_range(inode, mapping, pos, ret);
 960                 if (!error)
 961                         error = ret;
 962                 return error;
 963         }
 964
 965  out_unlock_internal:
 966         xfs_rwunlock(bdp, locktype);
 967  out_unlock_isem:
 968         if (need_isem)
 969                 up(&inode->i_sem);
 970  out_nounlocks:
 971         return -error;
 972 }
 973
 974 /*
 975  * All xfs metadata buffers except log state machine buffers
 976  * get this attached as their b_bdstrat callback function.
 977  * This is so that we can catch a buffer
 978  * after prematurely unpinning it to forcibly shutdown the filesystem.
 979  */
 980 int
 981 xfs_bdstrat_cb(struct xfs_buf *bp)
 982 {
 983         xfs_mount_t     *mp;
 984
 985         mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
 986         if (!XFS_FORCED_SHUTDOWN(mp)) {
 987                 pagebuf_iorequest(bp);
 988                 return 0;
 989         } else {
 990                 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
 991                 /*
 992                  * Metadata write that didn't get logged but
 993                  * written delayed anyway. These aren't associated
 994                  * with a transaction, and can be ignored.
 995                  */
 996                 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
 997                     (XFS_BUF_ISREAD(bp)) == 0)
 998                         return (xfs_bioerror_relse(bp));
 999                 else
1000                         return (xfs_bioerror(bp));
1001         }
1002 }
1003
1004
1005 int
1006 xfs_bmap(bhv_desc_t     *bdp,
1007         xfs_off_t       offset,
1008         ssize_t         count,
1009         int             flags,
1010         xfs_iomap_t     *iomapp,
1011         int             *niomaps)
1012 {
1013         xfs_inode_t     *ip = XFS_BHVTOI(bdp);
1014         xfs_iocore_t    *io = &ip->i_iocore;
1015
1016         ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
1017         ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
1018                ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
1019
1020         return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
1021 }
1022
1023 /*
1024  * Wrapper around bdstrat so that we can stop data
1025  * from going to disk in case we are shutting down the filesystem.
1026  * Typically user data goes thru this path; one of the exceptions
1027  * is the superblock.
1028  */
1029 int
1030 xfsbdstrat(
1031         struct xfs_mount        *mp,
1032         struct xfs_buf          *bp)
1033 {
1034         ASSERT(mp);
1035         if (!XFS_FORCED_SHUTDOWN(mp)) {
1036                 /* Grio redirection would go here
1037                  * if (XFS_BUF_IS_GRIO(bp)) {
1038                  */
1039
1040                 pagebuf_iorequest(bp);
1041                 return 0;
1042         }
1043
1044         xfs_buftrace("XFSBDSTRAT IOERROR", bp);
1045         return (xfs_bioerror_relse(bp));
1046 }
1047
1048 /*
1049  * If the underlying (data/log/rt) device is readonly, there are some
1050  * operations that cannot proceed.
1051  */
1052 int
1053 xfs_dev_is_read_only(
1054         xfs_mount_t             *mp,
1055         char                    *message)
1056 {
1057         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1058             xfs_readonly_buftarg(mp->m_logdev_targp) ||
1059             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1060                 cmn_err(CE_NOTE,
1061                         "XFS: %s required on read-only device.", message);
1062                 cmn_err(CE_NOTE,
1063                         "XFS: write access unavailable, cannot proceed.");
1064                 return EROFS;
1065         }
1066         return 0;
1067 }