linux/fs/xfs/xfs_rename.c
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   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_trans.h"
  23#include "xfs_sb.h"
  24#include "xfs_ag.h"
  25#include "xfs_dir2.h"
  26#include "xfs_mount.h"
  27#include "xfs_da_btree.h"
  28#include "xfs_bmap_btree.h"
  29#include "xfs_dinode.h"
  30#include "xfs_inode.h"
  31#include "xfs_inode_item.h"
  32#include "xfs_bmap.h"
  33#include "xfs_error.h"
  34#include "xfs_quota.h"
  35#include "xfs_utils.h"
  36#include "xfs_trans_space.h"
  37#include "xfs_vnodeops.h"
  38#include "xfs_trace.h"
  39
  40
  41/*
  42 * Enter all inodes for a rename transaction into a sorted array.
  43 */
  44STATIC void
  45xfs_sort_for_rename(
  46        xfs_inode_t     *dp1,   /* in: old (source) directory inode */
  47        xfs_inode_t     *dp2,   /* in: new (target) directory inode */
  48        xfs_inode_t     *ip1,   /* in: inode of old entry */
  49        xfs_inode_t     *ip2,   /* in: inode of new entry, if it
  50                                   already exists, NULL otherwise. */
  51        xfs_inode_t     **i_tab,/* out: array of inode returned, sorted */
  52        int             *num_inodes)  /* out: number of inodes in array */
  53{
  54        xfs_inode_t             *temp;
  55        int                     i, j;
  56
  57        /*
  58         * i_tab contains a list of pointers to inodes.  We initialize
  59         * the table here & we'll sort it.  We will then use it to
  60         * order the acquisition of the inode locks.
  61         *
  62         * Note that the table may contain duplicates.  e.g., dp1 == dp2.
  63         */
  64        i_tab[0] = dp1;
  65        i_tab[1] = dp2;
  66        i_tab[2] = ip1;
  67        if (ip2) {
  68                *num_inodes = 4;
  69                i_tab[3] = ip2;
  70        } else {
  71                *num_inodes = 3;
  72                i_tab[3] = NULL;
  73        }
  74
  75        /*
  76         * Sort the elements via bubble sort.  (Remember, there are at
  77         * most 4 elements to sort, so this is adequate.)
  78         */
  79        for (i = 0; i < *num_inodes; i++) {
  80                for (j = 1; j < *num_inodes; j++) {
  81                        if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
  82                                temp = i_tab[j];
  83                                i_tab[j] = i_tab[j-1];
  84                                i_tab[j-1] = temp;
  85                        }
  86                }
  87        }
  88}
  89
  90/*
  91 * xfs_rename
  92 */
  93int
  94xfs_rename(
  95        xfs_inode_t     *src_dp,
  96        struct xfs_name *src_name,
  97        xfs_inode_t     *src_ip,
  98        xfs_inode_t     *target_dp,
  99        struct xfs_name *target_name,
 100        xfs_inode_t     *target_ip)
 101{
 102        xfs_trans_t     *tp = NULL;
 103        xfs_mount_t     *mp = src_dp->i_mount;
 104        int             new_parent;             /* moving to a new dir */
 105        int             src_is_directory;       /* src_name is a directory */
 106        int             error;
 107        xfs_bmap_free_t free_list;
 108        xfs_fsblock_t   first_block;
 109        int             cancel_flags;
 110        int             committed;
 111        xfs_inode_t     *inodes[4];
 112        int             spaceres;
 113        int             num_inodes;
 114
 115        trace_xfs_rename(src_dp, target_dp, src_name, target_name);
 116
 117        new_parent = (src_dp != target_dp);
 118        src_is_directory = S_ISDIR(src_ip->i_d.di_mode);
 119
 120        xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
 121                                inodes, &num_inodes);
 122
 123        xfs_bmap_init(&free_list, &first_block);
 124        tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
 125        cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
 126        spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);
 127        error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
 128                        XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 129        if (error == ENOSPC) {
 130                spaceres = 0;
 131                error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
 132                                XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
 133        }
 134        if (error) {
 135                xfs_trans_cancel(tp, 0);
 136                goto std_return;
 137        }
 138
 139        /*
 140         * Attach the dquots to the inodes
 141         */
 142        error = xfs_qm_vop_rename_dqattach(inodes);
 143        if (error) {
 144                xfs_trans_cancel(tp, cancel_flags);
 145                goto std_return;
 146        }
 147
 148        /*
 149         * Lock all the participating inodes. Depending upon whether
 150         * the target_name exists in the target directory, and
 151         * whether the target directory is the same as the source
 152         * directory, we can lock from 2 to 4 inodes.
 153         */
 154        xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
 155
 156        /*
 157         * Join all the inodes to the transaction. From this point on,
 158         * we can rely on either trans_commit or trans_cancel to unlock
 159         * them.
 160         */
 161        xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
 162        if (new_parent)
 163                xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
 164        xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
 165        if (target_ip)
 166                xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
 167
 168        /*
 169         * If we are using project inheritance, we only allow renames
 170         * into our tree when the project IDs are the same; else the
 171         * tree quota mechanism would be circumvented.
 172         */
 173        if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
 174                     (xfs_get_projid(target_dp) != xfs_get_projid(src_ip)))) {
 175                error = XFS_ERROR(EXDEV);
 176                goto error_return;
 177        }
 178
 179        /*
 180         * Set up the target.
 181         */
 182        if (target_ip == NULL) {
 183                /*
 184                 * If there's no space reservation, check the entry will
 185                 * fit before actually inserting it.
 186                 */
 187                error = xfs_dir_canenter(tp, target_dp, target_name, spaceres);
 188                if (error)
 189                        goto error_return;
 190                /*
 191                 * If target does not exist and the rename crosses
 192                 * directories, adjust the target directory link count
 193                 * to account for the ".." reference from the new entry.
 194                 */
 195                error = xfs_dir_createname(tp, target_dp, target_name,
 196                                                src_ip->i_ino, &first_block,
 197                                                &free_list, spaceres);
 198                if (error == ENOSPC)
 199                        goto error_return;
 200                if (error)
 201                        goto abort_return;
 202
 203                xfs_trans_ichgtime(tp, target_dp,
 204                                        XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 205
 206                if (new_parent && src_is_directory) {
 207                        error = xfs_bumplink(tp, target_dp);
 208                        if (error)
 209                                goto abort_return;
 210                }
 211        } else { /* target_ip != NULL */
 212                /*
 213                 * If target exists and it's a directory, check that both
 214                 * target and source are directories and that target can be
 215                 * destroyed, or that neither is a directory.
 216                 */
 217                if (S_ISDIR(target_ip->i_d.di_mode)) {
 218                        /*
 219                         * Make sure target dir is empty.
 220                         */
 221                        if (!(xfs_dir_isempty(target_ip)) ||
 222                            (target_ip->i_d.di_nlink > 2)) {
 223                                error = XFS_ERROR(EEXIST);
 224                                goto error_return;
 225                        }
 226                }
 227
 228                /*
 229                 * Link the source inode under the target name.
 230                 * If the source inode is a directory and we are moving
 231                 * it across directories, its ".." entry will be
 232                 * inconsistent until we replace that down below.
 233                 *
 234                 * In case there is already an entry with the same
 235                 * name at the destination directory, remove it first.
 236                 */
 237                error = xfs_dir_replace(tp, target_dp, target_name,
 238                                        src_ip->i_ino,
 239                                        &first_block, &free_list, spaceres);
 240                if (error)
 241                        goto abort_return;
 242
 243                xfs_trans_ichgtime(tp, target_dp,
 244                                        XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 245
 246                /*
 247                 * Decrement the link count on the target since the target
 248                 * dir no longer points to it.
 249                 */
 250                error = xfs_droplink(tp, target_ip);
 251                if (error)
 252                        goto abort_return;
 253
 254                if (src_is_directory) {
 255                        /*
 256                         * Drop the link from the old "." entry.
 257                         */
 258                        error = xfs_droplink(tp, target_ip);
 259                        if (error)
 260                                goto abort_return;
 261                }
 262        } /* target_ip != NULL */
 263
 264        /*
 265         * Remove the source.
 266         */
 267        if (new_parent && src_is_directory) {
 268                /*
 269                 * Rewrite the ".." entry to point to the new
 270                 * directory.
 271                 */
 272                error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
 273                                        target_dp->i_ino,
 274                                        &first_block, &free_list, spaceres);
 275                ASSERT(error != EEXIST);
 276                if (error)
 277                        goto abort_return;
 278        }
 279
 280        /*
 281         * We always want to hit the ctime on the source inode.
 282         *
 283         * This isn't strictly required by the standards since the source
 284         * inode isn't really being changed, but old unix file systems did
 285         * it and some incremental backup programs won't work without it.
 286         */
 287        xfs_trans_ichgtime(tp, src_ip, XFS_ICHGTIME_CHG);
 288        xfs_trans_log_inode(tp, src_ip, XFS_ILOG_CORE);
 289
 290        /*
 291         * Adjust the link count on src_dp.  This is necessary when
 292         * renaming a directory, either within one parent when
 293         * the target existed, or across two parent directories.
 294         */
 295        if (src_is_directory && (new_parent || target_ip != NULL)) {
 296
 297                /*
 298                 * Decrement link count on src_directory since the
 299                 * entry that's moved no longer points to it.
 300                 */
 301                error = xfs_droplink(tp, src_dp);
 302                if (error)
 303                        goto abort_return;
 304        }
 305
 306        error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
 307                                        &first_block, &free_list, spaceres);
 308        if (error)
 309                goto abort_return;
 310
 311        xfs_trans_ichgtime(tp, src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 312        xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
 313        if (new_parent)
 314                xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
 315
 316        /*
 317         * If this is a synchronous mount, make sure that the
 318         * rename transaction goes to disk before returning to
 319         * the user.
 320         */
 321        if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
 322                xfs_trans_set_sync(tp);
 323        }
 324
 325        error = xfs_bmap_finish(&tp, &free_list, &committed);
 326        if (error) {
 327                xfs_bmap_cancel(&free_list);
 328                xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
 329                                 XFS_TRANS_ABORT));
 330                goto std_return;
 331        }
 332
 333        /*
 334         * trans_commit will unlock src_ip, target_ip & decrement
 335         * the vnode references.
 336         */
 337        return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 338
 339 abort_return:
 340        cancel_flags |= XFS_TRANS_ABORT;
 341 error_return:
 342        xfs_bmap_cancel(&free_list);
 343        xfs_trans_cancel(tp, cancel_flags);
 344 std_return:
 345        return error;
 346}
 347
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