ext4: replace open coded nofail allocation in ext4_free_blocks()

commit 7444a072c387a93ebee7066e8aee776954ab0e41 upstream.

ext4_free_blocks is looping around the allocation request and mimics
__GFP_NOFAIL behavior without any allocation fallback strategy. Let's
remove the open coded loop and replace it with __GFP_NOFAIL. Without the
flag the allocator has no way to find out never-fail requirement and
cannot help in any way.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.2:
 - Adjust context
 - s/ext4_free_data_cachep/ext4_free_ext_cachep/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 5baa7ba790919c81813c21ee7f4094e653fadb0e..7c03826bde260a45c85228028845e75962e90208 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4720,18 +4720,12 @@ do_more:
                /*
                 * blocks being freed are metadata. these blocks shouldn't
                 * be used until this transaction is committed
+                *
+                * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
+                * to fail.
                 */
-       retry:
-               new_entry = kmem_cache_alloc(ext4_free_ext_cachep, GFP_NOFS);
-               if (!new_entry) {
-                       /*
-                        * We use a retry loop because
-                        * ext4_free_blocks() is not allowed to fail.
-                        */
-                       cond_resched();
-                       congestion_wait(BLK_RW_ASYNC, HZ/50);
-                       goto retry;
-               }
+               new_entry = kmem_cache_alloc(ext4_free_ext_cachep,
+                               GFP_NOFS|__GFP_NOFAIL);
                new_entry->start_cluster = bit;
                new_entry->group  = block_group;
                new_entry->count = count_clusters;