VFS: move inode_lock into sync_sb_inodes

This patch makes 'sync_sb_inodes()' lock 'inode_lock', rather
than expect that the caller will do this.

This change was previously done by Hans Reiser <reiser@namesys.com>
and sat in the -mm tree.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index ae45f77..16519fe 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -424,8 +424,6 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
  * WB_SYNC_HOLD is a hack for sys_sync(): reattach the inode to sb->s_dirty so
  * that it can be located for waiting on in __writeback_single_inode().
  *
- * Called under inode_lock.
- *
  * If `bdi' is non-zero then we're being asked to writeback a specific queue.
  * This function assumes that the blockdev superblock's inodes are backed by
  * a variety of queues, so all inodes are searched.  For other superblocks,
@@ -446,6 +444,7 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
 {
        const unsigned long start = jiffies;    /* livelock avoidance */
 
+       spin_lock(&inode_lock);
        if (!wbc->for_kupdate || list_empty(&sb->s_io))
                queue_io(sb, wbc->older_than_this);
 
@@ -524,6 +523,7 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
                if (!list_empty(&sb->s_more_io))
                        wbc->more_io = 1;
        }
+       spin_unlock(&inode_lock);
        return;         /* Leave any unwritten inodes on s_io */
 }
 
@@ -565,11 +565,8 @@ restart:
                         * be unmounted by the time it is released.
                         */
                        if (down_read_trylock(&sb->s_umount)) {
-                               if (sb->s_root) {
-                                       spin_lock(&inode_lock);
+                               if (sb->s_root)
                                        sync_sb_inodes(sb, wbc);
-                                       spin_unlock(&inode_lock);
-                               }
                                up_read(&sb->s_umount);
                        }
                        spin_lock(&sb_lock);
@@ -607,9 +604,7 @@ void sync_inodes_sb(struct super_block *sb, int wait)
                        (inodes_stat.nr_inodes - inodes_stat.nr_unused) +
                        nr_dirty + nr_unstable;
        wbc.nr_to_write += wbc.nr_to_write / 2;         /* Bit more for luck */
-       spin_lock(&inode_lock);
        sync_sb_inodes(sb, &wbc);
-       spin_unlock(&inode_lock);
 }
 
 /*