4 files changed, 32 insertions, 8 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 818c4cf2de86..8a70b2a17d6f 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1078,7 +1078,7 @@ xfs_fs_write_inode(
                         error = 0;
                         goto out_unlock;
                 }
-                error = xfs_iflush(ip, 0);
+                error = xfs_iflush(ip, SYNC_TRYLOCK);
         }
 
  out_unlock:
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 6c10f1d2e3d3..594cd822d84d 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -761,8 +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))
@@ -788,9 +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;
         }
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index da871f532236..742c8330994a 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2835,7 +2835,7 @@ xfs_iflush(
          * Get the buffer containing the on-disk inode.
          */
         error = xfs_itobp(mp, NULL, ip, &dip, &bp,
-                                (flags & SYNC_WAIT) ? XBF_LOCK : XBF_TRYLOCK);
+                                (flags & SYNC_TRYLOCK) ? XBF_TRYLOCK : XBF_LOCK);
         if (error || !bp) {
                 xfs_ifunlock(ip);
                 return error;
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index fd4f398bd6f1..46cc40131d4a 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -760,11 +760,11 @@ xfs_inode_item_push(
          * Push the inode to it's backing buffer. This will not remove the
          * inode from the AIL - a further push will be required to trigger a
          * buffer push. However, this allows all the dirty inodes to be pushed
-         * to the buffer before it is pushed to disk. THe buffer IO completion
-         * will pull th einode from the AIL, mark it clean and unlock the flush
+         * to the buffer before it is pushed to disk. The buffer IO completion
+         * will pull the inode from the AIL, mark it clean and unlock the flush
          * lock.
          */
-        (void) xfs_iflush(ip, 0);
+        (void) xfs_iflush(ip, SYNC_TRYLOCK);
         xfs_iunlock(ip, XFS_ILOCK_SHARED);
 }