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