release/src-rt-6.x.4708/linux/linux-2.6.36/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_mount.h"
  28 #include "xfs_da_btree.h"
  29 #include "xfs_bmap_btree.h"
  30 #include "xfs_dinode.h"
  31 #include "xfs_inode.h"
  32 #include "xfs_inode_item.h"
  33 #include "xfs_bmap.h"
  34 #include "xfs_error.h"
  35 #include "xfs_quota.h"
  36 #include "xfs_utils.h"
  37 #include "xfs_trans_space.h"
  38 #include "xfs_vnodeops.h"
  39 #include "xfs_trace.h"
  40
  41
  42 /*
  43  * Enter all inodes for a rename transaction into a sorted array.
  44  */
  45 STATIC void
  46 xfs_sort_for_rename(
  47         xfs_inode_t     *dp1,   /* in: old (source) directory inode */
  48         xfs_inode_t     *dp2,   /* in: new (target) directory inode */
  49         xfs_inode_t     *ip1,   /* in: inode of old entry */
  50         xfs_inode_t     *ip2,   /* in: inode of new entry, if it
  51                                    already exists, NULL otherwise. */
  52         xfs_inode_t     **i_tab,/* out: array of inode returned, sorted */
  53         int             *num_inodes)  /* out: number of inodes in array */
  54 {
  55         xfs_inode_t             *temp;
  56         int                     i, j;
  57
  58         /*
  59          * i_tab contains a list of pointers to inodes.  We initialize
  60          * the table here & we'll sort it.  We will then use it to
  61          * order the acquisition of the inode locks.
  62          *
  63          * Note that the table may contain duplicates.  e.g., dp1 == dp2.
  64          */
  65         i_tab[0] = dp1;
  66         i_tab[1] = dp2;
  67         i_tab[2] = ip1;
  68         if (ip2) {
  69                 *num_inodes = 4;
  70                 i_tab[3] = ip2;
  71         } else {
  72                 *num_inodes = 3;
  73                 i_tab[3] = NULL;
  74         }
  75
  76         /*
  77          * Sort the elements via bubble sort.  (Remember, there are at
  78          * most 4 elements to sort, so this is adequate.)
  79          */
  80         for (i = 0; i < *num_inodes; i++) {
  81                 for (j = 1; j < *num_inodes; j++) {
  82                         if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
  83                                 temp = i_tab[j];
  84                                 i_tab[j] = i_tab[j-1];
  85                                 i_tab[j-1] = temp;
  86                         }
  87                 }
  88         }
  89 }
  90
  91 /*
  92  * xfs_rename
  93  */
  94 int
  95 xfs_rename(
  96         xfs_inode_t     *src_dp,
  97         struct xfs_name *src_name,
  98         xfs_inode_t     *src_ip,
  99         xfs_inode_t     *target_dp,
 100         struct xfs_name *target_name,
 101         xfs_inode_t     *target_ip)
 102 {
 103         xfs_trans_t     *tp = NULL;
 104         xfs_mount_t     *mp = src_dp->i_mount;
 105         int             new_parent;             /* moving to a new dir */
 106         int             src_is_directory;       /* src_name is a directory */
 107         int             error;
 108         xfs_bmap_free_t free_list;
 109         xfs_fsblock_t   first_block;
 110         int             cancel_flags;
 111         int             committed;
 112         xfs_inode_t     *inodes[4];
 113         int             spaceres;
 114         int             num_inodes;
 115
 116         trace_xfs_rename(src_dp, target_dp, src_name, target_name);
 117
 118         new_parent = (src_dp != target_dp);
 119         src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);
 120
 121         if (src_is_directory) {
 122                 /*
 123                  * Check for link count overflow on target_dp
 124                  */
 125                 if (target_ip == NULL && new_parent &&
 126                     target_dp->i_d.di_nlink >= XFS_MAXLINK) {
 127                         error = XFS_ERROR(EMLINK);
 128                         goto std_return;
 129                 }
 130         }
 131
 132         xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
 133                                 inodes, &num_inodes);
 134
 135         xfs_bmap_init(&free_list, &first_block);
 136         tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
 137         cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
 138         spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);
 139         error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
 140                         XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 141         if (error == ENOSPC) {
 142                 spaceres = 0;
 143                 error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
 144                                 XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 145         }
 146         if (error) {
 147                 xfs_trans_cancel(tp, 0);
 148                 goto std_return;
 149         }
 150
 151         /*
 152          * Attach the dquots to the inodes
 153          */
 154         error = xfs_qm_vop_rename_dqattach(inodes);
 155         if (error) {
 156                 xfs_trans_cancel(tp, cancel_flags);
 157                 goto std_return;
 158         }
 159
 160         /*
 161          * Lock all the participating inodes. Depending upon whether
 162          * the target_name exists in the target directory, and
 163          * whether the target directory is the same as the source
 164          * directory, we can lock from 2 to 4 inodes.
 165          */
 166         xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
 167
 168         /*
 169          * Join all the inodes to the transaction. From this point on,
 170          * we can rely on either trans_commit or trans_cancel to unlock
 171          * them.
 172          */
 173         xfs_trans_ijoin_ref(tp, src_dp, XFS_ILOCK_EXCL);
 174         if (new_parent)
 175                 xfs_trans_ijoin_ref(tp, target_dp, XFS_ILOCK_EXCL);
 176         xfs_trans_ijoin_ref(tp, src_ip, XFS_ILOCK_EXCL);
 177         if (target_ip)
 178                 xfs_trans_ijoin_ref(tp, target_ip, XFS_ILOCK_EXCL);
 179
 180         /*
 181          * If we are using project inheritance, we only allow renames
 182          * into our tree when the project IDs are the same; else the
 183          * tree quota mechanism would be circumvented.
 184          */
 185         if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
 186                      (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
 187                 error = XFS_ERROR(EXDEV);
 188                 goto error_return;
 189         }
 190
 191         /*
 192          * Set up the target.
 193          */
 194         if (target_ip == NULL) {
 195                 /*
 196                  * If there's no space reservation, check the entry will
 197                  * fit before actually inserting it.
 198                  */
 199                 error = xfs_dir_canenter(tp, target_dp, target_name, spaceres);
 200                 if (error)
 201                         goto error_return;
 202                 /*
 203                  * If target does not exist and the rename crosses
 204                  * directories, adjust the target directory link count
 205                  * to account for the ".." reference from the new entry.
 206                  */
 207                 error = xfs_dir_createname(tp, target_dp, target_name,
 208                                                 src_ip->i_ino, &first_block,
 209                                                 &free_list, spaceres);
 210                 if (error == ENOSPC)
 211                         goto error_return;
 212                 if (error)
 213                         goto abort_return;
 214                 xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 215
 216                 if (new_parent && src_is_directory) {
 217                         error = xfs_bumplink(tp, target_dp);
 218                         if (error)
 219                                 goto abort_return;
 220                 }
 221         } else { /* target_ip != NULL */
 222                 /*
 223                  * If target exists and it's a directory, check that both
 224                  * target and source are directories and that target can be
 225                  * destroyed, or that neither is a directory.
 226                  */
 227                 if ((target_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
 228                         /*
 229                          * Make sure target dir is empty.
 230                          */
 231                         if (!(xfs_dir_isempty(target_ip)) ||
 232                             (target_ip->i_d.di_nlink > 2)) {
 233                                 error = XFS_ERROR(EEXIST);
 234                                 goto error_return;
 235                         }
 236                 }
 237
 238                 /*
 239                  * Link the source inode under the target name.
 240                  * If the source inode is a directory and we are moving
 241                  * it across directories, its ".." entry will be
 242                  * inconsistent until we replace that down below.
 243                  *
 244                  * In case there is already an entry with the same
 245                  * name at the destination directory, remove it first.
 246                  */
 247                 error = xfs_dir_replace(tp, target_dp, target_name,
 248                                         src_ip->i_ino,
 249                                         &first_block, &free_list, spaceres);
 250                 if (error)
 251                         goto abort_return;
 252                 xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 253
 254                 /*
 255                  * Decrement the link count on the target since the target
 256                  * dir no longer points to it.
 257                  */
 258                 error = xfs_droplink(tp, target_ip);
 259                 if (error)
 260                         goto abort_return;
 261
 262                 if (src_is_directory) {
 263                         /*
 264                          * Drop the link from the old "." entry.
 265                          */
 266                         error = xfs_droplink(tp, target_ip);
 267                         if (error)
 268                                 goto abort_return;
 269                 }
 270         } /* target_ip != NULL */
 271
 272         /*
 273          * Remove the source.
 274          */
 275         if (new_parent && src_is_directory) {
 276                 /*
 277                  * Rewrite the ".." entry to point to the new
 278                  * directory.
 279                  */
 280                 error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
 281                                         target_dp->i_ino,
 282                                         &first_block, &free_list, spaceres);
 283                 ASSERT(error != EEXIST);
 284                 if (error)
 285                         goto abort_return;
 286         }
 287
 288         /*
 289          * We always want to hit the ctime on the source inode.
 290          *
 291          * This isn't strictly required by the standards since the source
 292          * inode isn't really being changed, but old unix file systems did
 293          * it and some incremental backup programs won't work without it.
 294          */
 295         xfs_ichgtime(src_ip, XFS_ICHGTIME_CHG);
 296
 297         /*
 298          * Adjust the link count on src_dp.  This is necessary when
 299          * renaming a directory, either within one parent when
 300          * the target existed, or across two parent directories.
 301          */
 302         if (src_is_directory && (new_parent || target_ip != NULL)) {
 303
 304                 /*
 305                  * Decrement link count on src_directory since the
 306                  * entry that's moved no longer points to it.
 307                  */
 308                 error = xfs_droplink(tp, src_dp);
 309                 if (error)
 310                         goto abort_return;
 311         }
 312
 313         error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
 314                                         &first_block, &free_list, spaceres);
 315         if (error)
 316                 goto abort_return;
 317
 318         xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 319         xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
 320         if (new_parent)
 321                 xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
 322
 323         /*
 324          * If this is a synchronous mount, make sure that the
 325          * rename transaction goes to disk before returning to
 326          * the user.
 327          */
 328         if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
 329                 xfs_trans_set_sync(tp);
 330         }
 331
 332         error = xfs_bmap_finish(&tp, &free_list, &committed);
 333         if (error) {
 334                 xfs_bmap_cancel(&free_list);
 335                 xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
 336                                  XFS_TRANS_ABORT));
 337                 goto std_return;
 338         }
 339
 340         /*
 341          * trans_commit will unlock src_ip, target_ip & decrement
 342          * the vnode references.
 343          */
 344         return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 345
 346  abort_return:
 347         cancel_flags |= XFS_TRANS_ABORT;
 348  error_return:
 349         xfs_bmap_cancel(&free_list);
 350         xfs_trans_cancel(tp, cancel_flags);
 351  std_return:
 352         return error;
 353 }