[XFS] Can't lock inodes in radix tree preload region

When we are inside a radix tree preload region, we cannot sleep. Recently
we moved the inode locking inside the preload region for the inode radix
tree. Fix that, and fix a missed unlock in another error path in the same
code at the same time.

SGI-PV: 987246

SGI-Modid: xfs-linux-melb:xfs-kern:32385a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

1 files changed, 11 insertions, 7 deletions

diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index a1f209b0596f..377c0cd14999 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -159,18 +159,19 @@ xfs_iget_cache_miss(
                 goto out_destroy;
         }
 
+        if (lock_flags)
+                xfs_ilock(ip, lock_flags);
+
         /*
          * Preload the radix tree so we can insert safely under the
-         * write spinlock.
+         * write spinlock. Note that we cannot sleep inside the preload
+         * region.
          */
         if (radix_tree_preload(GFP_KERNEL)) {
                 error = EAGAIN;
-                goto out_destroy;
+                goto out_unlock;
         }
 
-        if (lock_flags)
-                xfs_ilock(ip, lock_flags);
-
         mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
         first_index = agino & mask;
         write_lock(&pag->pag_ici_lock);
@@ -181,7 +182,7 @@ xfs_iget_cache_miss(
                 WARN_ON(error != -EEXIST);
                 XFS_STATS_INC(xs_ig_dup);
                 error = EAGAIN;
-                goto out_unlock;
+                goto out_preload_end;
         }
 
         /* These values _must_ be set before releasing the radix tree lock! */
@@ -193,9 +194,12 @@ xfs_iget_cache_miss(
         *ipp = ip;
         return 0;
 
-out_unlock:
+out_preload_end:
         write_unlock(&pag->pag_ici_lock);
         radix_tree_preload_end();
+out_unlock:
+        if (lock_flags)
+                xfs_iunlock(ip, lock_flags);
 out_destroy:
         xfs_idestroy(ip);
         return error;