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ext4: reduce contention on s_orphan_lock
Shuffle code around in ext4_orphan_add() and ext4_orphan_del() so that we avoid taking global s_orphan_lock in some cases and hold it for shorter time in other cases. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Jan Kara
Theodore Ts'o
parent
cd2c080c33
commit
d745a8c20c
1 changed files with 65 additions and 44 deletions
109
fs/ext4/namei.c
109
fs/ext4/namei.c
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@ -2540,13 +2540,17 @@ static int empty_dir(struct inode *inode)
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return 1;
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}
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/* ext4_orphan_add() links an unlinked or truncated inode into a list of
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/*
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* ext4_orphan_add() links an unlinked or truncated inode into a list of
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* such inodes, starting at the superblock, in case we crash before the
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* file is closed/deleted, or in case the inode truncate spans multiple
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* transactions and the last transaction is not recovered after a crash.
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*
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* At filesystem recovery time, we walk this list deleting unlinked
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* inodes and truncating linked inodes in ext4_orphan_cleanup().
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*
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* Orphan list manipulation functions must be called under i_mutex unless
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* we are just creating the inode or deleting it.
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*/
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int ext4_orphan_add(handle_t *handle, struct inode *inode)
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{
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@ -2554,13 +2558,19 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode)
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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struct ext4_iloc iloc;
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int err = 0, rc;
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bool dirty = false;
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if (!sbi->s_journal)
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return 0;
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mutex_lock(&sbi->s_orphan_lock);
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WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
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!mutex_is_locked(&inode->i_mutex));
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/*
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* Exit early if inode already is on orphan list. This is a big speedup
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* since we don't have to contend on the global s_orphan_lock.
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*/
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if (!list_empty(&EXT4_I(inode)->i_orphan))
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goto out_unlock;
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return 0;
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/*
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* Orphan handling is only valid for files with data blocks
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@ -2574,44 +2584,47 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode)
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BUFFER_TRACE(sbi->s_sbh, "get_write_access");
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err = ext4_journal_get_write_access(handle, sbi->s_sbh);
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if (err)
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goto out_unlock;
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goto out;
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err = ext4_reserve_inode_write(handle, inode, &iloc);
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if (err)
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goto out_unlock;
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goto out;
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mutex_lock(&sbi->s_orphan_lock);
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/*
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* Due to previous errors inode may be already a part of on-disk
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* orphan list. If so skip on-disk list modification.
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*/
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if (NEXT_ORPHAN(inode) && NEXT_ORPHAN(inode) <=
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(le32_to_cpu(sbi->s_es->s_inodes_count)))
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goto mem_insert;
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/* Insert this inode at the head of the on-disk orphan list... */
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NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
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sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
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err = ext4_handle_dirty_super(handle, sb);
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rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
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if (!err)
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err = rc;
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/* Only add to the head of the in-memory list if all the
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* previous operations succeeded. If the orphan_add is going to
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* fail (possibly taking the journal offline), we can't risk
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* leaving the inode on the orphan list: stray orphan-list
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* entries can cause panics at unmount time.
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*
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* This is safe: on error we're going to ignore the orphan list
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* anyway on the next recovery. */
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mem_insert:
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if (!err)
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list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
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if (!NEXT_ORPHAN(inode) || NEXT_ORPHAN(inode) >
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(le32_to_cpu(sbi->s_es->s_inodes_count))) {
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/* Insert this inode at the head of the on-disk orphan list */
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NEXT_ORPHAN(inode) = le32_to_cpu(sbi->s_es->s_last_orphan);
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sbi->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
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dirty = true;
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}
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list_add(&EXT4_I(inode)->i_orphan, &sbi->s_orphan);
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mutex_unlock(&sbi->s_orphan_lock);
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if (dirty) {
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err = ext4_handle_dirty_super(handle, sb);
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rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
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if (!err)
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err = rc;
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if (err) {
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/*
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* We have to remove inode from in-memory list if
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* addition to on disk orphan list failed. Stray orphan
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* list entries can cause panics at unmount time.
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*/
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mutex_lock(&sbi->s_orphan_lock);
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list_del(&EXT4_I(inode)->i_orphan);
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mutex_unlock(&sbi->s_orphan_lock);
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}
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}
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jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
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jbd_debug(4, "orphan inode %lu will point to %d\n",
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inode->i_ino, NEXT_ORPHAN(inode));
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out_unlock:
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mutex_unlock(&sbi->s_orphan_lock);
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out:
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ext4_std_error(sb, err);
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return err;
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}
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@ -2632,35 +2645,43 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode)
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if (!sbi->s_journal && !(sbi->s_mount_state & EXT4_ORPHAN_FS))
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return 0;
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mutex_lock(&sbi->s_orphan_lock);
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WARN_ON_ONCE(!(inode->i_state & (I_NEW | I_FREEING)) &&
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!mutex_is_locked(&inode->i_mutex));
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/* Do this quick check before taking global s_orphan_lock. */
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if (list_empty(&ei->i_orphan))
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goto out;
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return 0;
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ino_next = NEXT_ORPHAN(inode);
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prev = ei->i_orphan.prev;
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if (handle) {
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/* Grab inode buffer early before taking global s_orphan_lock */
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err = ext4_reserve_inode_write(handle, inode, &iloc);
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}
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mutex_lock(&sbi->s_orphan_lock);
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jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
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prev = ei->i_orphan.prev;
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list_del_init(&ei->i_orphan);
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/* If we're on an error path, we may not have a valid
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* transaction handle with which to update the orphan list on
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* disk, but we still need to remove the inode from the linked
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* list in memory. */
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if (!handle)
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goto out;
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err = ext4_reserve_inode_write(handle, inode, &iloc);
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if (err)
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if (!handle || err) {
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mutex_unlock(&sbi->s_orphan_lock);
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goto out_err;
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}
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ino_next = NEXT_ORPHAN(inode);
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if (prev == &sbi->s_orphan) {
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jbd_debug(4, "superblock will point to %u\n", ino_next);
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BUFFER_TRACE(sbi->s_sbh, "get_write_access");
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err = ext4_journal_get_write_access(handle, sbi->s_sbh);
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if (err)
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if (err) {
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mutex_unlock(&sbi->s_orphan_lock);
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goto out_brelse;
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}
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sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
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mutex_unlock(&sbi->s_orphan_lock);
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err = ext4_handle_dirty_super(handle, inode->i_sb);
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} else {
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struct ext4_iloc iloc2;
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@ -2670,20 +2691,20 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode)
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jbd_debug(4, "orphan inode %lu will point to %u\n",
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i_prev->i_ino, ino_next);
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err = ext4_reserve_inode_write(handle, i_prev, &iloc2);
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if (err)
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if (err) {
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mutex_unlock(&sbi->s_orphan_lock);
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goto out_brelse;
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}
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NEXT_ORPHAN(i_prev) = ino_next;
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err = ext4_mark_iloc_dirty(handle, i_prev, &iloc2);
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mutex_unlock(&sbi->s_orphan_lock);
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}
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if (err)
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goto out_brelse;
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NEXT_ORPHAN(inode) = 0;
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err = ext4_mark_iloc_dirty(handle, inode, &iloc);
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out_err:
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ext4_std_error(inode->i_sb, err);
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out:
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mutex_unlock(&sbi->s_orphan_lock);
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return err;
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out_brelse:
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