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 #include "xfs_trace.h"
  43
  44
  45 /*
  46  * Enter all inodes for a rename transaction into a sorted array.
  47  */
  48 STATIC void
  49 xfs_sort_for_rename(
  50         xfs_inode_t     *dp1,   /* in: old (source) directory inode */
  51         xfs_inode_t     *dp2,   /* in: new (target) directory inode */
  52         xfs_inode_t     *ip1,   /* in: inode of old entry */
  53         xfs_inode_t     *ip2,   /* in: inode of new entry, if it
  54                                    already exists, NULL otherwise. */
  55         xfs_inode_t     **i_tab,/* out: array of inode returned, sorted */
  56         int             *num_inodes)  /* out: number of inodes in array */
  57 {
  58         xfs_inode_t             *temp;
  59         int                     i, j;
  60
  61         /*
  62          * i_tab contains a list of pointers to inodes.  We initialize
  63          * the table here & we'll sort it.  We will then use it to
  64          * order the acquisition of the inode locks.
  65          *
  66          * Note that the table may contain duplicates.  e.g., dp1 == dp2.
  67          */
  68         i_tab[0] = dp1;
  69         i_tab[1] = dp2;
  70         i_tab[2] = ip1;
  71         if (ip2) {
  72                 *num_inodes = 4;
  73                 i_tab[3] = ip2;
  74         } else {
  75                 *num_inodes = 3;
  76                 i_tab[3] = NULL;
  77         }
  78
  79         /*
  80          * Sort the elements via bubble sort.  (Remember, there are at
  81          * most 4 elements to sort, so this is adequate.)
  82          */
  83         for (i = 0; i < *num_inodes; i++) {
  84                 for (j = 1; j < *num_inodes; j++) {
  85                         if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
  86                                 temp = i_tab[j];
  87                                 i_tab[j] = i_tab[j-1];
  88                                 i_tab[j-1] = temp;
  89                         }
  90                 }
  91         }
  92 }
  93
  94 /*
  95  * xfs_rename
  96  */
  97 int
  98 xfs_rename(
  99         xfs_inode_t     *src_dp,
 100         struct xfs_name *src_name,
 101         xfs_inode_t     *src_ip,
 102         xfs_inode_t     *target_dp,
 103         struct xfs_name *target_name,
 104         xfs_inode_t     *target_ip)
 105 {
 106         xfs_trans_t     *tp = NULL;
 107         xfs_mount_t     *mp = src_dp->i_mount;
 108         int             new_parent;             /* moving to a new dir */
 109         int             src_is_directory;       /* src_name is a directory */
 110         int             error;
 111         xfs_bmap_free_t free_list;
 112         xfs_fsblock_t   first_block;
 113         int             cancel_flags;
 114         int             committed;
 115         xfs_inode_t     *inodes[4];
 116         int             spaceres;
 117         int             num_inodes;
 118
 119         xfs_itrace_entry(src_dp);
 120         xfs_itrace_entry(target_dp);
 121
 122         if (DM_EVENT_ENABLED(src_dp, DM_EVENT_RENAME) ||
 123             DM_EVENT_ENABLED(target_dp, DM_EVENT_RENAME)) {
 124                 error = XFS_SEND_NAMESP(mp, DM_EVENT_RENAME,
 125                                         src_dp, DM_RIGHT_NULL,
 126                                         target_dp, DM_RIGHT_NULL,
 127                                         src_name->name, target_name->name,
 128                                         0, 0, 0);
 129                 if (error)
 130                         return error;
 131         }
 132         /* Return through std_return after this point. */
 133
 134         new_parent = (src_dp != target_dp);
 135         src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);
 136
 137         if (src_is_directory) {
 138                 /*
 139                  * Check for link count overflow on target_dp
 140                  */
 141                 if (target_ip == NULL && new_parent &&
 142                     target_dp->i_d.di_nlink >= XFS_MAXLINK) {
 143                         error = XFS_ERROR(EMLINK);
 144                         goto std_return;
 145                 }
 146         }
 147
 148         xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
 149                                 inodes, &num_inodes);
 150
 151         xfs_bmap_init(&free_list, &first_block);
 152         tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
 153         cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
 154         spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);
 155         error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
 156                         XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 157         if (error == ENOSPC) {
 158                 spaceres = 0;
 159                 error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
 160                                 XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 161         }
 162         if (error) {
 163                 xfs_trans_cancel(tp, 0);
 164                 goto std_return;
 165         }
 166
 167         /*
 168          * Attach the dquots to the inodes
 169          */
 170         error = xfs_qm_vop_rename_dqattach(inodes);
 171         if (error) {
 172                 xfs_trans_cancel(tp, cancel_flags);
 173                 goto std_return;
 174         }
 175
 176         /*
 177          * Lock all the participating inodes. Depending upon whether
 178          * the target_name exists in the target directory, and
 179          * whether the target directory is the same as the source
 180          * directory, we can lock from 2 to 4 inodes.
 181          */
 182         xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
 183
 184         /*
 185          * Join all the inodes to the transaction. From this point on,
 186          * we can rely on either trans_commit or trans_cancel to unlock
 187          * them.  Note that we need to add a vnode reference to the
 188          * directories since trans_commit & trans_cancel will decrement
 189          * them when they unlock the inodes.  Also, we need to be careful
 190          * not to add an inode to the transaction more than once.
 191          */
 192         IHOLD(src_dp);
 193         xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
 194
 195         if (new_parent) {
 196                 IHOLD(target_dp);
 197                 xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
 198         }
 199
 200         IHOLD(src_ip);
 201         xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
 202
 203         if (target_ip) {
 204                 IHOLD(target_ip);
 205                 xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
 206         }
 207
 208         /*
 209          * If we are using project inheritance, we only allow renames
 210          * into our tree when the project IDs are the same; else the
 211          * tree quota mechanism would be circumvented.
 212          */
 213         if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
 214                      (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
 215                 error = XFS_ERROR(EXDEV);
 216                 goto error_return;
 217         }
 218
 219         /*
 220          * Set up the target.
 221          */
 222         if (target_ip == NULL) {
 223                 /*
 224                  * If there's no space reservation, check the entry will
 225                  * fit before actually inserting it.
 226                  */
 227                 error = xfs_dir_canenter(tp, target_dp, target_name, spaceres);
 228                 if (error)
 229                         goto error_return;
 230                 /*
 231                  * If target does not exist and the rename crosses
 232                  * directories, adjust the target directory link count
 233                  * to account for the ".." reference from the new entry.
 234                  */
 235                 error = xfs_dir_createname(tp, target_dp, target_name,
 236                                                 src_ip->i_ino, &first_block,
 237                                                 &free_list, spaceres);
 238                 if (error == ENOSPC)
 239                         goto error_return;
 240                 if (error)
 241                         goto abort_return;
 242                 xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 243
 244                 if (new_parent && src_is_directory) {
 245                         error = xfs_bumplink(tp, target_dp);
 246                         if (error)
 247                                 goto abort_return;
 248                 }
 249         } else { /* target_ip != NULL */
 250                 /*
 251                  * If target exists and it's a directory, check that both
 252                  * target and source are directories and that target can be
 253                  * destroyed, or that neither is a directory.
 254                  */
 255                 if ((target_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
 256                         /*
 257                          * Make sure target dir is empty.
 258                          */
 259                         if (!(xfs_dir_isempty(target_ip)) ||
 260                             (target_ip->i_d.di_nlink > 2)) {
 261                                 error = XFS_ERROR(EEXIST);
 262                                 goto error_return;
 263                         }
 264                 }
 265
 266                 /*
 267                  * Link the source inode under the target name.
 268                  * If the source inode is a directory and we are moving
 269                  * it across directories, its ".." entry will be
 270                  * inconsistent until we replace that down below.
 271                  *
 272                  * In case there is already an entry with the same
 273                  * name at the destination directory, remove it first.
 274                  */
 275                 error = xfs_dir_replace(tp, target_dp, target_name,
 276                                         src_ip->i_ino,
 277                                         &first_block, &free_list, spaceres);
 278                 if (error)
 279                         goto abort_return;
 280                 xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 281
 282                 /*
 283                  * Decrement the link count on the target since the target
 284                  * dir no longer points to it.
 285                  */
 286                 error = xfs_droplink(tp, target_ip);
 287                 if (error)
 288                         goto abort_return;
 289
 290                 if (src_is_directory) {
 291                         /*
 292                          * Drop the link from the old "." entry.
 293                          */
 294                         error = xfs_droplink(tp, target_ip);
 295                         if (error)
 296                                 goto abort_return;
 297                 }
 298         } /* target_ip != NULL */
 299
 300         /*
 301          * Remove the source.
 302          */
 303         if (new_parent && src_is_directory) {
 304                 /*
 305                  * Rewrite the ".." entry to point to the new
 306                  * directory.
 307                  */
 308                 error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
 309                                         target_dp->i_ino,
 310                                         &first_block, &free_list, spaceres);
 311                 ASSERT(error != EEXIST);
 312                 if (error)
 313                         goto abort_return;
 314         }
 315
 316         /*
 317          * We always want to hit the ctime on the source inode.
 318          *
 319          * This isn't strictly required by the standards since the source
 320          * inode isn't really being changed, but old unix file systems did
 321          * it and some incremental backup programs won't work without it.
 322          */
 323         xfs_ichgtime(src_ip, XFS_ICHGTIME_CHG);
 324
 325         /*
 326          * Adjust the link count on src_dp.  This is necessary when
 327          * renaming a directory, either within one parent when
 328          * the target existed, or across two parent directories.
 329          */
 330         if (src_is_directory && (new_parent || target_ip != NULL)) {
 331
 332                 /*
 333                  * Decrement link count on src_directory since the
 334                  * entry that's moved no longer points to it.
 335                  */
 336                 error = xfs_droplink(tp, src_dp);
 337                 if (error)
 338                         goto abort_return;
 339         }
 340
 341         error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
 342                                         &first_block, &free_list, spaceres);
 343         if (error)
 344                 goto abort_return;
 345
 346         xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 347         xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
 348         if (new_parent)
 349                 xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
 350
 351         /*
 352          * If this is a synchronous mount, make sure that the
 353          * rename transaction goes to disk before returning to
 354          * the user.
 355          */
 356         if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
 357                 xfs_trans_set_sync(tp);
 358         }
 359
 360         error = xfs_bmap_finish(&tp, &free_list, &committed);
 361         if (error) {
 362                 xfs_bmap_cancel(&free_list);
 363                 xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
 364                                  XFS_TRANS_ABORT));
 365                 goto std_return;
 366         }
 367
 368         /*
 369          * trans_commit will unlock src_ip, target_ip & decrement
 370          * the vnode references.
 371          */
 372         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 373
 374         /* Fall through to std_return with error = 0 or errno from
 375          * xfs_trans_commit      */
 376 std_return:
 377         if (DM_EVENT_ENABLED(src_dp, DM_EVENT_POSTRENAME) ||
 378             DM_EVENT_ENABLED(target_dp, DM_EVENT_POSTRENAME)) {
 379                 (void) XFS_SEND_NAMESP (mp, DM_EVENT_POSTRENAME,
 380                                         src_dp, DM_RIGHT_NULL,
 381                                         target_dp, DM_RIGHT_NULL,
 382                                         src_name->name, target_name->name,
 383                                         0, error, 0);
 384         }
 385         return error;
 386
 387  abort_return:
 388         cancel_flags |= XFS_TRANS_ABORT;
 389         /* FALLTHROUGH */
 390  error_return:
 391         xfs_bmap_cancel(&free_list);
 392         xfs_trans_cancel(tp, cancel_flags);
 393         goto std_return;
 394 }