ext4: replace open coded nofail allocation in ext4_free_blocks()

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>
Cc: stable@vger.kernel.org

1 files changed, 5 insertions, 11 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 1c535fa67640..2299d629eeb1 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4815,18 +4815,12 @@ 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_data_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_data_cachep,
+                                GFP_NOFS|__GFP_NOFAIL);
                 new_entry->efd_start_cluster = bit;
                 new_entry->efd_group = block_group;
                 new_entry->efd_count = count_clusters;