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