Merge branch 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/kaber/nf-2.6

1 files changed, 29 insertions, 6 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index e22f0057d21f..594cd822d84d 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -425,8 +425,7 @@ xfs_quiesce_attr(
         /* Push the superblock and write an unmount record */
         error = xfs_log_sbcount(mp, 1);
         if (error)
-                xfs_fs_cmn_err(CE_WARN, mp,
-                                "xfs_attr_quiesce: failed to log sb changes. "
+                xfs_warn(mp, "xfs_attr_quiesce: failed to log sb changes. "
                                 "Frozen image may not be consistent.");
         xfs_log_unmount_write(mp);
         xfs_unmountfs_writesb(mp);
@@ -762,8 +761,10 @@ xfs_reclaim_inode(
         struct xfs_perag        *pag,
         int                     sync_mode)
 {
-        int     error = 0;
+        int     error;
 
+restart:
+        error = 0;
         xfs_ilock(ip, XFS_ILOCK_EXCL);
         if (!xfs_iflock_nowait(ip)) {
                 if (!(sync_mode & SYNC_WAIT))
@@ -789,9 +790,31 @@ xfs_reclaim_inode(
         if (xfs_inode_clean(ip))
                 goto reclaim;
 
-        /* Now we have an inode that needs flushing */
-        error = xfs_iflush(ip, sync_mode);
+        /*
+         * Now we have an inode that needs flushing.
+         *
+         * We do a nonblocking flush here even if we are doing a SYNC_WAIT
+         * reclaim as we can deadlock with inode cluster removal.
+         * xfs_ifree_cluster() can lock the inode buffer before it locks the
+         * ip->i_lock, and we are doing the exact opposite here. As a result,
+         * doing a blocking xfs_itobp() to get the cluster buffer will result
+         * in an ABBA deadlock with xfs_ifree_cluster().
+         *
+         * As xfs_ifree_cluser() must gather all inodes that are active in the
+         * cache to mark them stale, if we hit this case we don't actually want
+         * to do IO here - we want the inode marked stale so we can simply
+         * reclaim it. Hence if we get an EAGAIN error on a SYNC_WAIT flush,
+         * just unlock the inode, back off and try again. Hopefully the next
+         * pass through will see the stale flag set on the inode.
+         */
+        error = xfs_iflush(ip, SYNC_TRYLOCK | sync_mode);
         if (sync_mode & SYNC_WAIT) {
+                if (error == EAGAIN) {
+                        xfs_iunlock(ip, XFS_ILOCK_EXCL);
+                        /* backoff longer than in xfs_ifree_cluster */
+                        delay(2);
+                        goto restart;
+                }
                 xfs_iflock(ip);
                 goto reclaim;
         }
@@ -806,7 +829,7 @@ xfs_reclaim_inode(
          * pass on the error.
          */
         if (error && error != EAGAIN && !XFS_FORCED_SHUTDOWN(ip->i_mount)) {
-                xfs_fs_cmn_err(CE_WARN, ip->i_mount,
+                xfs_warn(ip->i_mount,
                         "inode 0x%llx background reclaim flush failed with %d",
                         (long long)ip->i_ino, error);
         }