fs/xfs/xfs_dfrag.c

   1 /*
   2  * Copyright (c) 2000-2006 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_types.h"
  21 #include "xfs_log.h"
  22 #include "xfs_trans.h"
  23 #include "xfs_sb.h"
  24 #include "xfs_ag.h"
  25 #include "xfs_mount.h"
  26 #include "xfs_bmap_btree.h"
  27 #include "xfs_dinode.h"
  28 #include "xfs_inode.h"
  29 #include "xfs_inode_item.h"
  30 #include "xfs_bmap.h"
  31 #include "xfs_itable.h"
  32 #include "xfs_dfrag.h"
  33 #include "xfs_error.h"
  34 #include "xfs_vnodeops.h"
  35 #include "xfs_trace.h"
  36
  37
  38 static int xfs_swap_extents(
  39         xfs_inode_t     *ip,    /* target inode */
  40         xfs_inode_t     *tip,   /* tmp inode */
  41         xfs_swapext_t   *sxp);
  42
  43 /*
  44  * ioctl interface for swapext
  45  */
  46 int
  47 xfs_swapext(
  48         xfs_swapext_t   *sxp)
  49 {
  50         xfs_inode_t     *ip, *tip;
  51         struct fd       f, tmp;
  52         int             error = 0;
  53
  54         /* Pull information for the target fd */
  55         f = fdget((int)sxp->sx_fdtarget);
  56         if (!f.file) {
  57                 error = XFS_ERROR(EINVAL);
  58                 goto out;
  59         }
  60
  61         if (!(f.file->f_mode & FMODE_WRITE) ||
  62             !(f.file->f_mode & FMODE_READ) ||
  63             (f.file->f_flags & O_APPEND)) {
  64                 error = XFS_ERROR(EBADF);
  65                 goto out_put_file;
  66         }
  67
  68         tmp = fdget((int)sxp->sx_fdtmp);
  69         if (!tmp.file) {
  70                 error = XFS_ERROR(EINVAL);
  71                 goto out_put_file;
  72         }
  73
  74         if (!(tmp.file->f_mode & FMODE_WRITE) ||
  75             !(tmp.file->f_mode & FMODE_READ) ||
  76             (tmp.file->f_flags & O_APPEND)) {
  77                 error = XFS_ERROR(EBADF);
  78                 goto out_put_tmp_file;
  79         }
  80
  81         if (IS_SWAPFILE(f.file->f_path.dentry->d_inode) ||
  82             IS_SWAPFILE(tmp.file->f_path.dentry->d_inode)) {
  83                 error = XFS_ERROR(EINVAL);
  84                 goto out_put_tmp_file;
  85         }
  86
  87         ip = XFS_I(f.file->f_path.dentry->d_inode);
  88         tip = XFS_I(tmp.file->f_path.dentry->d_inode);
  89
  90         if (ip->i_mount != tip->i_mount) {
  91                 error = XFS_ERROR(EINVAL);
  92                 goto out_put_tmp_file;
  93         }
  94
  95         if (ip->i_ino == tip->i_ino) {
  96                 error = XFS_ERROR(EINVAL);
  97                 goto out_put_tmp_file;
  98         }
  99
 100         if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
 101                 error = XFS_ERROR(EIO);
 102                 goto out_put_tmp_file;
 103         }
 104
 105         error = xfs_swap_extents(ip, tip, sxp);
 106
 107  out_put_tmp_file:
 108         fdput(tmp);
 109  out_put_file:
 110         fdput(f);
 111  out:
 112         return error;
 113 }
 114
 115 /*
 116  * We need to check that the format of the data fork in the temporary inode is
 117  * valid for the target inode before doing the swap. This is not a problem with
 118  * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
 119  * data fork depending on the space the attribute fork is taking so we can get
 120  * invalid formats on the target inode.
 121  *
 122  * E.g. target has space for 7 extents in extent format, temp inode only has
 123  * space for 6.  If we defragment down to 7 extents, then the tmp format is a
 124  * btree, but when swapped it needs to be in extent format. Hence we can't just
 125  * blindly swap data forks on attr2 filesystems.
 126  *
 127  * Note that we check the swap in both directions so that we don't end up with
 128  * a corrupt temporary inode, either.
 129  *
 130  * Note that fixing the way xfs_fsr sets up the attribute fork in the source
 131  * inode will prevent this situation from occurring, so all we do here is
 132  * reject and log the attempt. basically we are putting the responsibility on
 133  * userspace to get this right.
 134  */
 135 static int
 136 xfs_swap_extents_check_format(
 137         xfs_inode_t     *ip,    /* target inode */
 138         xfs_inode_t     *tip)   /* tmp inode */
 139 {
 140
 141         /* Should never get a local format */
 142         if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL ||
 143             tip->i_d.di_format == XFS_DINODE_FMT_LOCAL)
 144                 return EINVAL;
 145
 146         /*
 147          * if the target inode has less extents that then temporary inode then
 148          * why did userspace call us?
 149          */
 150         if (ip->i_d.di_nextents < tip->i_d.di_nextents)
 151                 return EINVAL;
 152
 153         /*
 154          * if the target inode is in extent form and the temp inode is in btree
 155          * form then we will end up with the target inode in the wrong format
 156          * as we already know there are less extents in the temp inode.
 157          */
 158         if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 159             tip->i_d.di_format == XFS_DINODE_FMT_BTREE)
 160                 return EINVAL;
 161
 162         /* Check temp in extent form to max in target */
 163         if (tip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 164             XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) >
 165                         XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
 166                 return EINVAL;
 167
 168         /* Check target in extent form to max in temp */
 169         if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 170             XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) >
 171                         XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
 172                 return EINVAL;
 173
 174         /*
 175          * If we are in a btree format, check that the temp root block will fit
 176          * in the target and that it has enough extents to be in btree format
 177          * in the target.
 178          *
 179          * Note that we have to be careful to allow btree->extent conversions
 180          * (a common defrag case) which will occur when the temp inode is in
 181          * extent format...
 182          */
 183         if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
 184                 if (XFS_IFORK_BOFF(ip) &&
 185                     tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip))
 186                         return EINVAL;
 187                 if (XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <=
 188                     XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
 189                         return EINVAL;
 190         }
 191
 192         /* Reciprocal target->temp btree format checks */
 193         if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
 194                 if (XFS_IFORK_BOFF(tip) &&
 195                     ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip))
 196                         return EINVAL;
 197
 198                 if (XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <=
 199                     XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
 200                         return EINVAL;
 201         }
 202
 203         return 0;
 204 }
 205
 206 static int
 207 xfs_swap_extents(
 208         xfs_inode_t     *ip,    /* target inode */
 209         xfs_inode_t     *tip,   /* tmp inode */
 210         xfs_swapext_t   *sxp)
 211 {
 212         xfs_mount_t     *mp = ip->i_mount;
 213         xfs_trans_t     *tp;
 214         xfs_bstat_t     *sbp = &sxp->sx_stat;
 215         xfs_ifork_t     *tempifp, *ifp, *tifp;
 216         int             src_log_flags, target_log_flags;
 217         int             error = 0;
 218         int             aforkblks = 0;
 219         int             taforkblks = 0;
 220         __uint64_t      tmp;
 221
 222         tempifp = kmem_alloc(sizeof(xfs_ifork_t), KM_MAYFAIL);
 223         if (!tempifp) {
 224                 error = XFS_ERROR(ENOMEM);
 225                 goto out;
 226         }
 227
 228         /*
 229          * we have to do two separate lock calls here to keep lockdep
 230          * happy. If we try to get all the locks in one call, lock will
 231          * report false positives when we drop the ILOCK and regain them
 232          * below.
 233          */
 234         xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);
 235         xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
 236
 237         /* Verify that both files have the same format */
 238         if ((ip->i_d.di_mode & S_IFMT) != (tip->i_d.di_mode & S_IFMT)) {
 239                 error = XFS_ERROR(EINVAL);
 240                 goto out_unlock;
 241         }
 242
 243         /* Verify both files are either real-time or non-realtime */
 244         if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
 245                 error = XFS_ERROR(EINVAL);
 246                 goto out_unlock;
 247         }
 248
 249         error = -filemap_write_and_wait(VFS_I(tip)->i_mapping);
 250         if (error)
 251                 goto out_unlock;
 252         truncate_pagecache_range(VFS_I(tip), 0, -1);
 253
 254         /* Verify O_DIRECT for ftmp */
 255         if (VN_CACHED(VFS_I(tip)) != 0) {
 256                 error = XFS_ERROR(EINVAL);
 257                 goto out_unlock;
 258         }
 259
 260         /* Verify all data are being swapped */
 261         if (sxp->sx_offset != 0 ||
 262             sxp->sx_length != ip->i_d.di_size ||
 263             sxp->sx_length != tip->i_d.di_size) {
 264                 error = XFS_ERROR(EFAULT);
 265                 goto out_unlock;
 266         }
 267
 268         trace_xfs_swap_extent_before(ip, 0);
 269         trace_xfs_swap_extent_before(tip, 1);
 270
 271         /* check inode formats now that data is flushed */
 272         error = xfs_swap_extents_check_format(ip, tip);
 273         if (error) {
 274                 xfs_notice(mp,
 275                     "%s: inode 0x%llx format is incompatible for exchanging.",
 276                                 __func__, ip->i_ino);
 277                 goto out_unlock;
 278         }
 279
 280         /*
 281          * Compare the current change & modify times with that
 282          * passed in.  If they differ, we abort this swap.
 283          * This is the mechanism used to ensure the calling
 284          * process that the file was not changed out from
 285          * under it.
 286          */
 287         if ((sbp->bs_ctime.tv_sec != VFS_I(ip)->i_ctime.tv_sec) ||
 288             (sbp->bs_ctime.tv_nsec != VFS_I(ip)->i_ctime.tv_nsec) ||
 289             (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
 290             (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
 291                 error = XFS_ERROR(EBUSY);
 292                 goto out_unlock;
 293         }
 294
 295         /* We need to fail if the file is memory mapped.  Once we have tossed
 296          * all existing pages, the page fault will have no option
 297          * but to go to the filesystem for pages. By making the page fault call
 298          * vop_read (or write in the case of autogrow) they block on the iolock
 299          * until we have switched the extents.
 300          */
 301         if (VN_MAPPED(VFS_I(ip))) {
 302                 error = XFS_ERROR(EBUSY);
 303                 goto out_unlock;
 304         }
 305
 306         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 307         xfs_iunlock(tip, XFS_ILOCK_EXCL);
 308
 309         /*
 310          * There is a race condition here since we gave up the
 311          * ilock.  However, the data fork will not change since
 312          * we have the iolock (locked for truncation too) so we
 313          * are safe.  We don't really care if non-io related
 314          * fields change.
 315          */
 316         truncate_pagecache_range(VFS_I(ip), 0, -1);
 317
 318         tp = xfs_trans_alloc(mp, XFS_TRANS_SWAPEXT);
 319         if ((error = xfs_trans_reserve(tp, 0,
 320                                      XFS_ICHANGE_LOG_RES(mp), 0,
 321                                      0, 0))) {
 322                 xfs_iunlock(ip,  XFS_IOLOCK_EXCL);
 323                 xfs_iunlock(tip, XFS_IOLOCK_EXCL);
 324                 xfs_trans_cancel(tp, 0);
 325                 goto out;
 326         }
 327         xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
 328
 329         /*
 330          * Count the number of extended attribute blocks
 331          */
 332         if ( ((XFS_IFORK_Q(ip) != 0) && (ip->i_d.di_anextents > 0)) &&
 333              (ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
 334                 error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &aforkblks);
 335                 if (error)
 336                         goto out_trans_cancel;
 337         }
 338         if ( ((XFS_IFORK_Q(tip) != 0) && (tip->i_d.di_anextents > 0)) &&
 339              (tip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
 340                 error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK,
 341                         &taforkblks);
 342                 if (error)
 343                         goto out_trans_cancel;
 344         }
 345
 346         /*
 347          * Swap the data forks of the inodes
 348          */
 349         ifp = &ip->i_df;
 350         tifp = &tip->i_df;
 351         *tempifp = *ifp;        /* struct copy */
 352         *ifp = *tifp;           /* struct copy */
 353         *tifp = *tempifp;       /* struct copy */
 354
 355         /*
 356          * Fix the on-disk inode values
 357          */
 358         tmp = (__uint64_t)ip->i_d.di_nblocks;
 359         ip->i_d.di_nblocks = tip->i_d.di_nblocks - taforkblks + aforkblks;
 360         tip->i_d.di_nblocks = tmp + taforkblks - aforkblks;
 361
 362         tmp = (__uint64_t) ip->i_d.di_nextents;
 363         ip->i_d.di_nextents = tip->i_d.di_nextents;
 364         tip->i_d.di_nextents = tmp;
 365
 366         tmp = (__uint64_t) ip->i_d.di_format;
 367         ip->i_d.di_format = tip->i_d.di_format;
 368         tip->i_d.di_format = tmp;
 369
 370         /*
 371          * The extents in the source inode could still contain speculative
 372          * preallocation beyond EOF (e.g. the file is open but not modified
 373          * while defrag is in progress). In that case, we need to copy over the
 374          * number of delalloc blocks the data fork in the source inode is
 375          * tracking beyond EOF so that when the fork is truncated away when the
 376          * temporary inode is unlinked we don't underrun the i_delayed_blks
 377          * counter on that inode.
 378          */
 379         ASSERT(tip->i_delayed_blks == 0);
 380         tip->i_delayed_blks = ip->i_delayed_blks;
 381         ip->i_delayed_blks = 0;
 382
 383         src_log_flags = XFS_ILOG_CORE;
 384         switch (ip->i_d.di_format) {
 385         case XFS_DINODE_FMT_EXTENTS:
 386                 /* If the extents fit in the inode, fix the
 387                  * pointer.  Otherwise it's already NULL or
 388                  * pointing to the extent.
 389                  */
 390                 if (ip->i_d.di_nextents <= XFS_INLINE_EXTS) {
 391                         ifp->if_u1.if_extents =
 392                                 ifp->if_u2.if_inline_ext;
 393                 }
 394                 src_log_flags |= XFS_ILOG_DEXT;
 395                 break;
 396         case XFS_DINODE_FMT_BTREE:
 397                 src_log_flags |= XFS_ILOG_DBROOT;
 398                 break;
 399         }
 400
 401         target_log_flags = XFS_ILOG_CORE;
 402         switch (tip->i_d.di_format) {
 403         case XFS_DINODE_FMT_EXTENTS:
 404                 /* If the extents fit in the inode, fix the
 405                  * pointer.  Otherwise it's already NULL or
 406                  * pointing to the extent.
 407                  */
 408                 if (tip->i_d.di_nextents <= XFS_INLINE_EXTS) {
 409                         tifp->if_u1.if_extents =
 410                                 tifp->if_u2.if_inline_ext;
 411                 }
 412                 target_log_flags |= XFS_ILOG_DEXT;
 413                 break;
 414         case XFS_DINODE_FMT_BTREE:
 415                 target_log_flags |= XFS_ILOG_DBROOT;
 416                 break;
 417         }
 418
 419
 420         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 421         xfs_trans_ijoin(tp, tip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 422
 423         xfs_trans_log_inode(tp, ip,  src_log_flags);
 424         xfs_trans_log_inode(tp, tip, target_log_flags);
 425
 426         /*
 427          * If this is a synchronous mount, make sure that the
 428          * transaction goes to disk before returning to the user.
 429          */
 430         if (mp->m_flags & XFS_MOUNT_WSYNC)
 431                 xfs_trans_set_sync(tp);
 432
 433         error = xfs_trans_commit(tp, 0);
 434
 435         trace_xfs_swap_extent_after(ip, 0);
 436         trace_xfs_swap_extent_after(tip, 1);
 437 out:
 438         kmem_free(tempifp);
 439         return error;
 440
 441 out_unlock:
 442         xfs_iunlock(ip,  XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 443         xfs_iunlock(tip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 444         goto out;
 445
 446 out_trans_cancel:
 447         xfs_trans_cancel(tp, 0);
 448         goto out_unlock;
 449 }