fs/xfs/xfs_rename.c

   1 /*
   2  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_log.h"
  22 #include "xfs_inum.h"
  23 #include "xfs_trans.h"
  24 #include "xfs_sb.h"
  25 #include "xfs_ag.h"
  26 #include "xfs_dir2.h"
  27 #include "xfs_dmapi.h"
  28 #include "xfs_mount.h"
  29 #include "xfs_da_btree.h"
  30 #include "xfs_bmap_btree.h"
  31 #include "xfs_dir2_sf.h"
  32 #include "xfs_attr_sf.h"
  33 #include "xfs_dinode.h"
  34 #include "xfs_inode.h"
  35 #include "xfs_inode_item.h"
  36 #include "xfs_bmap.h"
  37 #include "xfs_error.h"
  38 #include "xfs_quota.h"
  39 #include "xfs_utils.h"
  40 #include "xfs_trans_space.h"
  41 #include "xfs_vnodeops.h"
  42
  43
  44 /*
  45  * Given an array of up to 4 inode pointers, unlock the pointed to inodes.
  46  * If there are fewer than 4 entries in the array, the empty entries will
  47  * be at the end and will have NULL pointers in them.
  48  */
  49 STATIC void
  50 xfs_rename_unlock4(
  51         xfs_inode_t     **i_tab,
  52         uint            lock_mode)
  53 {
  54         int     i;
  55
  56         xfs_iunlock(i_tab[0], lock_mode);
  57         for (i = 1; i < 4; i++) {
  58                 if (i_tab[i] == NULL)
  59                         break;
  60
  61                 /*
  62                  * Watch out for duplicate entries in the table.
  63                  */
  64                 if (i_tab[i] != i_tab[i-1])
  65                         xfs_iunlock(i_tab[i], lock_mode);
  66         }
  67 }
  68
  69 /*
  70  * Enter all inodes for a rename transaction into a sorted array.
  71  */
  72 STATIC void
  73 xfs_sort_for_rename(
  74         xfs_inode_t     *dp1,   /* in: old (source) directory inode */
  75         xfs_inode_t     *dp2,   /* in: new (target) directory inode */
  76         xfs_inode_t     *ip1,   /* in: inode of old entry */
  77         xfs_inode_t     *ip2,   /* in: inode of new entry, if it
  78                                    already exists, NULL otherwise. */
  79         xfs_inode_t     **i_tab,/* out: array of inode returned, sorted */
  80         int             *num_inodes)  /* out: number of inodes in array */
  81 {
  82         xfs_inode_t             *temp;
  83         int                     i, j;
  84
  85         /*
  86          * i_tab contains a list of pointers to inodes.  We initialize
  87          * the table here & we'll sort it.  We will then use it to
  88          * order the acquisition of the inode locks.
  89          *
  90          * Note that the table may contain duplicates.  e.g., dp1 == dp2.
  91          */
  92         i_tab[0] = dp1;
  93         i_tab[1] = dp2;
  94         i_tab[2] = ip1;
  95         if (ip2) {
  96                 *num_inodes = 4;
  97                 i_tab[3] = ip2;
  98         } else {
  99                 *num_inodes = 3;
 100                 i_tab[3] = NULL;
 101         }
 102
 103         /*
 104          * Sort the elements via bubble sort.  (Remember, there are at
 105          * most 4 elements to sort, so this is adequate.)
 106          */
 107         for (i = 0; i < *num_inodes; i++) {
 108                 for (j = 1; j < *num_inodes; j++) {
 109                         if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
 110                                 temp = i_tab[j];
 111                                 i_tab[j] = i_tab[j-1];
 112                                 i_tab[j-1] = temp;
 113                         }
 114                 }
 115         }
 116 }
 117
 118 /*
 119  * xfs_rename
 120  */
 121 int
 122 xfs_rename(
 123         xfs_inode_t     *src_dp,
 124         struct xfs_name *src_name,
 125         xfs_inode_t     *src_ip,
 126         xfs_inode_t     *target_dp,
 127         struct xfs_name *target_name,
 128         xfs_inode_t     *target_ip)
 129 {
 130         xfs_trans_t     *tp = NULL;
 131         xfs_mount_t     *mp = src_dp->i_mount;
 132         int             new_parent;             /* moving to a new dir */
 133         int             src_is_directory;       /* src_name is a directory */
 134         int             error;
 135         xfs_bmap_free_t free_list;
 136         xfs_fsblock_t   first_block;
 137         int             cancel_flags;
 138         int             committed;
 139         xfs_inode_t     *inodes[4];
 140         int             spaceres;
 141         int             num_inodes;
 142
 143         xfs_itrace_entry(src_dp);
 144         xfs_itrace_entry(target_dp);
 145
 146         if (DM_EVENT_ENABLED(src_dp, DM_EVENT_RENAME) ||
 147             DM_EVENT_ENABLED(target_dp, DM_EVENT_RENAME)) {
 148                 error = XFS_SEND_NAMESP(mp, DM_EVENT_RENAME,
 149                                         src_dp, DM_RIGHT_NULL,
 150                                         target_dp, DM_RIGHT_NULL,
 151                                         src_name->name, target_name->name,
 152                                         0, 0, 0);
 153                 if (error)
 154                         return error;
 155         }
 156         /* Return through std_return after this point. */
 157
 158         new_parent = (src_dp != target_dp);
 159         src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);
 160
 161         if (src_is_directory) {
 162                 /*
 163                  * Check for link count overflow on target_dp
 164                  */
 165                 if (target_ip == NULL && new_parent &&
 166                     target_dp->i_d.di_nlink >= XFS_MAXLINK) {
 167                         error = XFS_ERROR(EMLINK);
 168                         goto std_return;
 169                 }
 170         }
 171
 172         xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
 173                                 inodes, &num_inodes);
 174
 175         XFS_BMAP_INIT(&free_list, &first_block);
 176         tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
 177         cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
 178         spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);
 179         error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
 180                         XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 181         if (error == ENOSPC) {
 182                 spaceres = 0;
 183                 error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
 184                                 XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 185         }
 186         if (error) {
 187                 xfs_trans_cancel(tp, 0);
 188                 goto std_return;
 189         }
 190
 191         /*
 192          * Attach the dquots to the inodes
 193          */
 194         if ((error = XFS_QM_DQVOPRENAME(mp, inodes))) {
 195                 xfs_trans_cancel(tp, cancel_flags);
 196                 goto std_return;
 197         }
 198
 199         /*
 200          * Lock all the participating inodes. Depending upon whether
 201          * the target_name exists in the target directory, and
 202          * whether the target directory is the same as the source
 203          * directory, we can lock from 2 to 4 inodes.
 204          */
 205         xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
 206
 207         /*
 208          * If we are using project inheritance, we only allow renames
 209          * into our tree when the project IDs are the same; else the
 210          * tree quota mechanism would be circumvented.
 211          */
 212         if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
 213                      (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
 214                 error = XFS_ERROR(EXDEV);
 215                 xfs_rename_unlock4(inodes, XFS_ILOCK_EXCL);
 216                 xfs_trans_cancel(tp, cancel_flags);
 217                 goto std_return;
 218         }
 219
 220         /*
 221          * Join all the inodes to the transaction. From this point on,
 222          * we can rely on either trans_commit or trans_cancel to unlock
 223          * them.  Note that we need to add a vnode reference to the
 224          * directories since trans_commit & trans_cancel will decrement
 225          * them when they unlock the inodes.  Also, we need to be careful
 226          * not to add an inode to the transaction more than once.
 227          */
 228         IHOLD(src_dp);
 229         xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
 230
 231         if (new_parent) {
 232                 IHOLD(target_dp);
 233                 xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
 234         }
 235
 236         IHOLD(src_ip);
 237         xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
 238
 239         if (target_ip) {
 240                 IHOLD(target_ip);
 241                 xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
 242         }
 243
 244         /*
 245          * Set up the target.
 246          */
 247         if (target_ip == NULL) {
 248                 /*
 249                  * If there's no space reservation, check the entry will
 250                  * fit before actually inserting it.
 251                  */
 252                 error = xfs_dir_canenter(tp, target_dp, target_name, spaceres);
 253                 if (error)
 254                         goto error_return;
 255                 /*
 256                  * If target does not exist and the rename crosses
 257                  * directories, adjust the target directory link count
 258                  * to account for the ".." reference from the new entry.
 259                  */
 260                 error = xfs_dir_createname(tp, target_dp, target_name,
 261                                                 src_ip->i_ino, &first_block,
 262                                                 &free_list, spaceres);
 263                 if (error == ENOSPC)
 264                         goto error_return;
 265                 if (error)
 266                         goto abort_return;
 267                 xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 268
 269                 if (new_parent && src_is_directory) {
 270                         error = xfs_bumplink(tp, target_dp);
 271                         if (error)
 272                                 goto abort_return;
 273                 }
 274         } else { /* target_ip != NULL */
 275                 /*
 276                  * If target exists and it's a directory, check that both
 277                  * target and source are directories and that target can be
 278                  * destroyed, or that neither is a directory.
 279                  */
 280                 if ((target_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
 281                         /*
 282                          * Make sure target dir is empty.
 283                          */
 284                         if (!(xfs_dir_isempty(target_ip)) ||
 285                             (target_ip->i_d.di_nlink > 2)) {
 286                                 error = XFS_ERROR(EEXIST);
 287                                 goto error_return;
 288                         }
 289                 }
 290
 291                 /*
 292                  * Link the source inode under the target name.
 293                  * If the source inode is a directory and we are moving
 294                  * it across directories, its ".." entry will be
 295                  * inconsistent until we replace that down below.
 296                  *
 297                  * In case there is already an entry with the same
 298                  * name at the destination directory, remove it first.
 299                  */
 300                 error = xfs_dir_replace(tp, target_dp, target_name,
 301                                         src_ip->i_ino,
 302                                         &first_block, &free_list, spaceres);
 303                 if (error)
 304                         goto abort_return;
 305                 xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 306
 307                 /*
 308                  * Decrement the link count on the target since the target
 309                  * dir no longer points to it.
 310                  */
 311                 error = xfs_droplink(tp, target_ip);
 312                 if (error)
 313                         goto abort_return;
 314
 315                 if (src_is_directory) {
 316                         /*
 317                          * Drop the link from the old "." entry.
 318                          */
 319                         error = xfs_droplink(tp, target_ip);
 320                         if (error)
 321                                 goto abort_return;
 322                 }
 323         } /* target_ip != NULL */
 324
 325         /*
 326          * Remove the source.
 327          */
 328         if (new_parent && src_is_directory) {
 329                 /*
 330                  * Rewrite the ".." entry to point to the new
 331                  * directory.
 332                  */
 333                 error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
 334                                         target_dp->i_ino,
 335                                         &first_block, &free_list, spaceres);
 336                 ASSERT(error != EEXIST);
 337                 if (error)
 338                         goto abort_return;
 339         }
 340
 341         /*
 342          * We always want to hit the ctime on the source inode.
 343          *
 344          * This isn't strictly required by the standards since the source
 345          * inode isn't really being changed, but old unix file systems did
 346          * it and some incremental backup programs won't work without it.
 347          */
 348         xfs_ichgtime(src_ip, XFS_ICHGTIME_CHG);
 349
 350         /*
 351          * Adjust the link count on src_dp.  This is necessary when
 352          * renaming a directory, either within one parent when
 353          * the target existed, or across two parent directories.
 354          */
 355         if (src_is_directory && (new_parent || target_ip != NULL)) {
 356
 357                 /*
 358                  * Decrement link count on src_directory since the
 359                  * entry that's moved no longer points to it.
 360                  */
 361                 error = xfs_droplink(tp, src_dp);
 362                 if (error)
 363                         goto abort_return;
 364         }
 365
 366         error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
 367                                         &first_block, &free_list, spaceres);
 368         if (error)
 369                 goto abort_return;
 370         xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 371
 372         /*
 373          * Update the generation counts on all the directory inodes
 374          * that we're modifying.
 375          */
 376         src_dp->i_gen++;
 377         xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
 378
 379         if (new_parent) {
 380                 target_dp->i_gen++;
 381                 xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
 382         }
 383
 384         /*
 385          * If this is a synchronous mount, make sure that the
 386          * rename transaction goes to disk before returning to
 387          * the user.
 388          */
 389         if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
 390                 xfs_trans_set_sync(tp);
 391         }
 392
 393         error = xfs_bmap_finish(&tp, &free_list, &committed);
 394         if (error) {
 395                 xfs_bmap_cancel(&free_list);
 396                 xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
 397                                  XFS_TRANS_ABORT));
 398                 goto std_return;
 399         }
 400
 401         /*
 402          * trans_commit will unlock src_ip, target_ip & decrement
 403          * the vnode references.
 404          */
 405         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 406
 407         /* Fall through to std_return with error = 0 or errno from
 408          * xfs_trans_commit      */
 409 std_return:
 410         if (DM_EVENT_ENABLED(src_dp, DM_EVENT_POSTRENAME) ||
 411             DM_EVENT_ENABLED(target_dp, DM_EVENT_POSTRENAME)) {
 412                 (void) XFS_SEND_NAMESP (mp, DM_EVENT_POSTRENAME,
 413                                         src_dp, DM_RIGHT_NULL,
 414                                         target_dp, DM_RIGHT_NULL,
 415                                         src_name->name, target_name->name,
 416                                         0, error, 0);
 417         }
 418         return error;
 419
 420  abort_return:
 421         cancel_flags |= XFS_TRANS_ABORT;
 422         /* FALLTHROUGH */
 423  error_return:
 424         xfs_bmap_cancel(&free_list);
 425         xfs_trans_cancel(tp, cancel_flags);
 426         goto std_return;
 427 }