fs: skip I_FREEING inodes in writeback_sb_inodes

Skip I_FREEING inodes just like I_WILL_FREE and I_NEW when walking the
writeback lists.  Currenly this can't happen, but once we move from
inode_lock to more fine grained locking we can have an inode that's
still on the writeback lists but has I_FREEING set, and we absolutely
need to skip it here, just like we do for all other inode list walks.

Based on a patch from Dave Chinner.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 7a24cc9..f6af81a 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -487,10 +487,16 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                        return 0;
                }
 
-               if (inode->i_state & (I_NEW | I_WILL_FREE)) {
+               /*
+                * Don't bother with new inodes or inodes beeing freed, first
+                * kind does not need peridic writeout yet, and for the latter
+                * kind writeout is handled by the freer.
+                */
+               if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
                        requeue_io(inode);
                        continue;
                }
+
                /*
                 * Was this inode dirtied after sync_sb_inodes was called?
                 * This keeps sync from extra jobs and livelock.
@@ -498,7 +504,6 @@ static int writeback_sb_inodes(struct super_block *sb, struct bdi_writeback *wb,
                if (inode_dirtied_after(inode, wbc->wb_start))
                        return 1;
 
-               BUG_ON(inode->i_state & I_FREEING);
                __iget(inode);
                pages_skipped = wbc->pages_skipped;
                writeback_single_inode(inode, wbc);