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 = S_ISDIR(src_ip->i_d.di_mode);
 120
 121         xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
 122                                 inodes, &num_inodes);
 123
 124         xfs_bmap_init(&free_list, &first_block);
 125         tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
 126         cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
 127         spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);
 128         error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
 129                         XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 130         if (error == ENOSPC) {
 131                 spaceres = 0;
 132                 error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
 133                                 XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 134         }
 135         if (error) {
 136                 xfs_trans_cancel(tp, 0);
 137                 goto std_return;
 138         }
 139
 140         /*
 141          * Attach the dquots to the inodes
 142          */
 143         error = xfs_qm_vop_rename_dqattach(inodes);
 144         if (error) {
 145                 xfs_trans_cancel(tp, cancel_flags);
 146                 goto std_return;
 147         }
 148
 149         /*
 150          * Lock all the participating inodes. Depending upon whether
 151          * the target_name exists in the target directory, and
 152          * whether the target directory is the same as the source
 153          * directory, we can lock from 2 to 4 inodes.
 154          */
 155         xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
 156
 157         /*
 158          * Join all the inodes to the transaction. From this point on,
 159          * we can rely on either trans_commit or trans_cancel to unlock
 160          * them.
 161          */
 162         xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
 163         if (new_parent)
 164                 xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
 165         xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
 166         if (target_ip)
 167                 xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
 168
 169         /*
 170          * If we are using project inheritance, we only allow renames
 171          * into our tree when the project IDs are the same; else the
 172          * tree quota mechanism would be circumvented.
 173          */
 174         if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
 175                      (xfs_get_projid(target_dp) != xfs_get_projid(src_ip)))) {
 176                 error = XFS_ERROR(EXDEV);
 177                 goto error_return;
 178         }
 179
 180         /*
 181          * Set up the target.
 182          */
 183         if (target_ip == NULL) {
 184                 /*
 185                  * If there's no space reservation, check the entry will
 186                  * fit before actually inserting it.
 187                  */
 188                 error = xfs_dir_canenter(tp, target_dp, target_name, spaceres);
 189                 if (error)
 190                         goto error_return;
 191                 /*
 192                  * If target does not exist and the rename crosses
 193                  * directories, adjust the target directory link count
 194                  * to account for the ".." reference from the new entry.
 195                  */
 196                 error = xfs_dir_createname(tp, target_dp, target_name,
 197                                                 src_ip->i_ino, &first_block,
 198                                                 &free_list, spaceres);
 199                 if (error == ENOSPC)
 200                         goto error_return;
 201                 if (error)
 202                         goto abort_return;
 203
 204                 xfs_trans_ichgtime(tp, target_dp,
 205                                         XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 206
 207                 if (new_parent && src_is_directory) {
 208                         error = xfs_bumplink(tp, target_dp);
 209                         if (error)
 210                                 goto abort_return;
 211                 }
 212         } else { /* target_ip != NULL */
 213                 /*
 214                  * If target exists and it's a directory, check that both
 215                  * target and source are directories and that target can be
 216                  * destroyed, or that neither is a directory.
 217                  */
 218                 if (S_ISDIR(target_ip->i_d.di_mode)) {
 219                         /*
 220                          * Make sure target dir is empty.
 221                          */
 222                         if (!(xfs_dir_isempty(target_ip)) ||
 223                             (target_ip->i_d.di_nlink > 2)) {
 224                                 error = XFS_ERROR(EEXIST);
 225                                 goto error_return;
 226                         }
 227                 }
 228
 229                 /*
 230                  * Link the source inode under the target name.
 231                  * If the source inode is a directory and we are moving
 232                  * it across directories, its ".." entry will be
 233                  * inconsistent until we replace that down below.
 234                  *
 235                  * In case there is already an entry with the same
 236                  * name at the destination directory, remove it first.
 237                  */
 238                 error = xfs_dir_replace(tp, target_dp, target_name,
 239                                         src_ip->i_ino,
 240                                         &first_block, &free_list, spaceres);
 241                 if (error)
 242                         goto abort_return;
 243
 244                 xfs_trans_ichgtime(tp, target_dp,
 245                                         XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 246
 247                 /*
 248                  * Decrement the link count on the target since the target
 249                  * dir no longer points to it.
 250                  */
 251                 error = xfs_droplink(tp, target_ip);
 252                 if (error)
 253                         goto abort_return;
 254
 255                 if (src_is_directory) {
 256                         /*
 257                          * Drop the link from the old "." entry.
 258                          */
 259                         error = xfs_droplink(tp, target_ip);
 260                         if (error)
 261                                 goto abort_return;
 262                 }
 263         } /* target_ip != NULL */
 264
 265         /*
 266          * Remove the source.
 267          */
 268         if (new_parent && src_is_directory) {
 269                 /*
 270                  * Rewrite the ".." entry to point to the new
 271                  * directory.
 272                  */
 273                 error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
 274                                         target_dp->i_ino,
 275                                         &first_block, &free_list, spaceres);
 276                 ASSERT(error != EEXIST);
 277                 if (error)
 278                         goto abort_return;
 279         }
 280
 281         /*
 282          * We always want to hit the ctime on the source inode.
 283          *
 284          * This isn't strictly required by the standards since the source
 285          * inode isn't really being changed, but old unix file systems did
 286          * it and some incremental backup programs won't work without it.
 287          */
 288         xfs_trans_ichgtime(tp, src_ip, XFS_ICHGTIME_CHG);
 289         xfs_trans_log_inode(tp, src_ip, XFS_ILOG_CORE);
 290
 291         /*
 292          * Adjust the link count on src_dp.  This is necessary when
 293          * renaming a directory, either within one parent when
 294          * the target existed, or across two parent directories.
 295          */
 296         if (src_is_directory && (new_parent || target_ip != NULL)) {
 297
 298                 /*
 299                  * Decrement link count on src_directory since the
 300                  * entry that's moved no longer points to it.
 301                  */
 302                 error = xfs_droplink(tp, src_dp);
 303                 if (error)
 304                         goto abort_return;
 305         }
 306
 307         error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
 308                                         &first_block, &free_list, spaceres);
 309         if (error)
 310                 goto abort_return;
 311
 312         xfs_trans_ichgtime(tp, src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 313         xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
 314         if (new_parent)
 315                 xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
 316
 317         /*
 318          * If this is a synchronous mount, make sure that the
 319          * rename transaction goes to disk before returning to
 320          * the user.
 321          */
 322         if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
 323                 xfs_trans_set_sync(tp);
 324         }
 325
 326         error = xfs_bmap_finish(&tp, &free_list, &committed);
 327         if (error) {
 328                 xfs_bmap_cancel(&free_list);
 329                 xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
 330                                  XFS_TRANS_ABORT));
 331                 goto std_return;
 332         }
 333
 334         /*
 335          * trans_commit will unlock src_ip, target_ip & decrement
 336          * the vnode references.
 337          */
 338         return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 339
 340  abort_return:
 341         cancel_flags |= XFS_TRANS_ABORT;
 342  error_return:
 343         xfs_bmap_cancel(&free_list);
 344         xfs_trans_cancel(tp, cancel_flags);
 345  std_return:
 346         return error;
 347 }