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root/fs/xfs/xfs_rename.c

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DEFINITIONS

This source file includes following definitions.
  1. xfs_rename_unlock4
  2. xfs_sort_for_rename
  3. xfs_rename

/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_utils.h"
#include "xfs_trans_space.h"
#include "xfs_vnodeops.h"


/*
 * Given an array of up to 4 inode pointers, unlock the pointed to inodes.
 * If there are fewer than 4 entries in the array, the empty entries will
 * be at the end and will have NULL pointers in them.
 */
STATIC void
xfs_rename_unlock4(
        xfs_inode_t     **i_tab,
        uint            lock_mode)
{
        int     i;

        xfs_iunlock(i_tab[0], lock_mode);
        for (i = 1; i < 4; i++) {
                if (i_tab[i] == NULL)
                        break;

                /*
                 * Watch out for duplicate entries in the table.
                 */
                if (i_tab[i] != i_tab[i-1])
                        xfs_iunlock(i_tab[i], lock_mode);
        }
}

/*
 * Enter all inodes for a rename transaction into a sorted array.
 */
STATIC void
xfs_sort_for_rename(
        xfs_inode_t     *dp1,   /* in: old (source) directory inode */
        xfs_inode_t     *dp2,   /* in: new (target) directory inode */
        xfs_inode_t     *ip1,   /* in: inode of old entry */
        xfs_inode_t     *ip2,   /* in: inode of new entry, if it
                                   already exists, NULL otherwise. */
        xfs_inode_t     **i_tab,/* out: array of inode returned, sorted */
        int             *num_inodes)  /* out: number of inodes in array */
{
        xfs_inode_t             *temp;
        int                     i, j;

        /*
         * i_tab contains a list of pointers to inodes.  We initialize
         * the table here & we'll sort it.  We will then use it to
         * order the acquisition of the inode locks.
         *
         * Note that the table may contain duplicates.  e.g., dp1 == dp2.
         */
        i_tab[0] = dp1;
        i_tab[1] = dp2;
        i_tab[2] = ip1;
        if (ip2) {
                *num_inodes = 4;
                i_tab[3] = ip2;
        } else {
                *num_inodes = 3;
                i_tab[3] = NULL;
        }

        /*
         * Sort the elements via bubble sort.  (Remember, there are at
         * most 4 elements to sort, so this is adequate.)
         */
        for (i = 0; i < *num_inodes; i++) {
                for (j = 1; j < *num_inodes; j++) {
                        if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
                                temp = i_tab[j];
                                i_tab[j] = i_tab[j-1];
                                i_tab[j-1] = temp;
                        }
                }
        }
}

/*
 * xfs_rename
 */
int
xfs_rename(
        xfs_inode_t     *src_dp,
        struct xfs_name *src_name,
        xfs_inode_t     *src_ip,
        xfs_inode_t     *target_dp,
        struct xfs_name *target_name,
        xfs_inode_t     *target_ip)
{
        xfs_trans_t     *tp = NULL;
        xfs_mount_t     *mp = src_dp->i_mount;
        int             new_parent;             /* moving to a new dir */
        int             src_is_directory;       /* src_name is a directory */
        int             error;
        xfs_bmap_free_t free_list;
        xfs_fsblock_t   first_block;
        int             cancel_flags;
        int             committed;
        xfs_inode_t     *inodes[4];
        int             spaceres;
        int             num_inodes;

        xfs_itrace_entry(src_dp);
        xfs_itrace_entry(target_dp);

        if (DM_EVENT_ENABLED(src_dp, DM_EVENT_RENAME) ||
            DM_EVENT_ENABLED(target_dp, DM_EVENT_RENAME)) {
                error = XFS_SEND_NAMESP(mp, DM_EVENT_RENAME,
                                        src_dp, DM_RIGHT_NULL,
                                        target_dp, DM_RIGHT_NULL,
                                        src_name->name, target_name->name,
                                        0, 0, 0);
                if (error)
                        return error;
        }
        /* Return through std_return after this point. */

        new_parent = (src_dp != target_dp);
        src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);

        if (src_is_directory) {
                /*
                 * Check for link count overflow on target_dp
                 */
                if (target_ip == NULL && new_parent &&
                    target_dp->i_d.di_nlink >= XFS_MAXLINK) {
                        error = XFS_ERROR(EMLINK);
                        goto std_return;
                }
        }

        xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
                                inodes, &num_inodes);

        XFS_BMAP_INIT(&free_list, &first_block);
        tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
        cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
        spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);
        error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
                        XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
        if (error == ENOSPC) {
                spaceres = 0;
                error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
                                XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
        }
        if (error) {
                xfs_trans_cancel(tp, 0);
                goto std_return;
        }

        /*
         * Attach the dquots to the inodes
         */
        if ((error = XFS_QM_DQVOPRENAME(mp, inodes))) {
                xfs_trans_cancel(tp, cancel_flags);
                goto std_return;
        }

        /*
         * Lock all the participating inodes. Depending upon whether
         * the target_name exists in the target directory, and
         * whether the target directory is the same as the source
         * directory, we can lock from 2 to 4 inodes.
         */
        xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);

        /*
         * If we are using project inheritance, we only allow renames
         * into our tree when the project IDs are the same; else the
         * tree quota mechanism would be circumvented.
         */
        if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
                     (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
                error = XFS_ERROR(EXDEV);
                xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
                xfs_trans_cancel(tp, cancel_flags);
                goto std_return;
        }

        /*
         * Join all the inodes to the transaction. From this point on,
         * we can rely on either trans_commit or trans_cancel to unlock
         * them.  Note that we need to add a vnode reference to the
         * directories since trans_commit & trans_cancel will decrement
         * them when they unlock the inodes.  Also, we need to be careful
         * not to add an inode to the transaction more than once.
         */
        IHOLD(src_dp);
        xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);

        if (new_parent) {
                IHOLD(target_dp);
                xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
        }

        IHOLD(src_ip);
        xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);

        if (target_ip) {
                IHOLD(target_ip);
                xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
        }

        /*
         * Set up the target.
         */
        if (target_ip == NULL) {
                /*
                 * If there's no space reservation, check the entry will
                 * fit before actually inserting it.
                 */
                error = xfs_dir_canenter(tp, target_dp, target_name, spaceres);
                if (error)
                        goto error_return;
                /*
                 * If target does not exist and the rename crosses
                 * directories, adjust the target directory link count
                 * to account for the ".." reference from the new entry.
                 */
                error = xfs_dir_createname(tp, target_dp, target_name,
                                                src_ip->i_ino, &first_block,
                                                &free_list, spaceres);
                if (error == ENOSPC)
                        goto error_return;
                if (error)
                        goto abort_return;
                xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);

                if (new_parent && src_is_directory) {
                        error = xfs_bumplink(tp, target_dp);
                        if (error)
                                goto abort_return;
                }
        } else { /* target_ip != NULL */
                /*
                 * If target exists and it's a directory, check that both
                 * target and source are directories and that target can be
                 * destroyed, or that neither is a directory.
                 */
                if ((target_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
                        /*
                         * Make sure target dir is empty.
                         */
                        if (!(xfs_dir_isempty(target_ip)) ||
                            (target_ip->i_d.di_nlink > 2)) {
                                error = XFS_ERROR(EEXIST);
                                goto error_return;
                        }
                }

                /*
                 * Link the source inode under the target name.
                 * If the source inode is a directory and we are moving
                 * it across directories, its ".." entry will be
                 * inconsistent until we replace that down below.
                 *
                 * In case there is already an entry with the same
                 * name at the destination directory, remove it first.
                 */
                error = xfs_dir_replace(tp, target_dp, target_name,
                                        src_ip->i_ino,
                                        &first_block, &free_list, spaceres);
                if (error)
                        goto abort_return;
                xfs_ichgtime(target_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);

                /*
                 * Decrement the link count on the target since the target
                 * dir no longer points to it.
                 */
                error = xfs_droplink(tp, target_ip);
                if (error)
                        goto abort_return;

                if (src_is_directory) {
                        /*
                         * Drop the link from the old "." entry.
                         */
                        error = xfs_droplink(tp, target_ip);
                        if (error)
                                goto abort_return;
                }
        } /* target_ip != NULL */

        /*
         * Remove the source.
         */
        if (new_parent && src_is_directory) {
                /*
                 * Rewrite the ".." entry to point to the new
                 * directory.
                 */
                error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
                                        target_dp->i_ino,
                                        &first_block, &free_list, spaceres);
                ASSERT(error != EEXIST);
                if (error)
                        goto abort_return;
        }

        /*
         * We always want to hit the ctime on the source inode.
         *
         * This isn't strictly required by the standards since the source
         * inode isn't really being changed, but old unix file systems did
         * it and some incremental backup programs won't work without it.
         */
        xfs_ichgtime(src_ip, XFS_ICHGTIME_CHG);

        /*
         * Adjust the link count on src_dp.  This is necessary when
         * renaming a directory, either within one parent when
         * the target existed, or across two parent directories.
         */
        if (src_is_directory && (new_parent || target_ip != NULL)) {

                /*
                 * Decrement link count on src_directory since the
                 * entry that's moved no longer points to it.
                 */
                error = xfs_droplink(tp, src_dp);
                if (error)
                        goto abort_return;
        }

        error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
                                        &first_block, &free_list, spaceres);
        if (error)
                goto abort_return;
        xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);

        /*
         * Update the generation counts on all the directory inodes
         * that we're modifying.
         */
        src_dp->i_gen++;
        xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);

        if (new_parent) {
                target_dp->i_gen++;
                xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
        }

        /*
         * If this is a synchronous mount, make sure that the
         * rename transaction goes to disk before returning to
         * the user.
         */
        if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
                xfs_trans_set_sync(tp);
        }

        error = xfs_bmap_finish(&tp, &free_list, &committed);
        if (error) {
                xfs_bmap_cancel(&free_list);
                xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
                                 XFS_TRANS_ABORT));
                goto std_return;
        }

        /*
         * trans_commit will unlock src_ip, target_ip & decrement
         * the vnode references.
         */
        error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);

        /* Fall through to std_return with error = 0 or errno from
         * xfs_trans_commit      */
std_return:
        if (DM_EVENT_ENABLED(src_dp, DM_EVENT_POSTRENAME) ||
            DM_EVENT_ENABLED(target_dp, DM_EVENT_POSTRENAME)) {
                (void) XFS_SEND_NAMESP (mp, DM_EVENT_POSTRENAME,
                                        src_dp, DM_RIGHT_NULL,
                                        target_dp, DM_RIGHT_NULL,
                                        src_name->name, target_name->name,
                                        0, error, 0);
        }
        return error;

 abort_return:
        cancel_flags |= XFS_TRANS_ABORT;
        /* FALLTHROUGH */
 error_return:
        xfs_bmap_cancel(&free_list);
        xfs_trans_cancel(tp, cancel_flags);
        goto std_return;
}

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