xfs: fix memory reclaim deadlock on agi buffer
Note xfs_iget can be called while holding a locked agi buffer. If
it goes into memory reclaim then inode teardown may try to lock the
same buffer. Prevent the deadlock by calling radix_tree_preload
with GFP_NOFS.
Signed-off-by: Peter Watkins <treestem@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index 7f81397..1bb4365 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -317,9 +317,10 @@
/*
* Preload the radix tree so we can insert safely under the
* write spinlock. Note that we cannot sleep inside the preload
- * region.
+ * region. Since we can be called from transaction context, don't
+ * recurse into the file system.
*/
- if (radix_tree_preload(GFP_KERNEL)) {
+ if (radix_tree_preload(GFP_NOFS)) {
error = EAGAIN;
goto out_destroy;
}