ext4: don't hold spinlock while calling ext4_issue_discard()

We can't hold the block group spinlock because we ext4_issue_discard()
calls wait and hence can get rescheduled.

Google-Bug-Id: 3017678

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 53472e2..ccdfec6 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4696,12 +4696,12 @@ do_more:
                 * with group lock held. generate_buddy look at
                 * them with group lock_held
                 */
+               if (test_opt(sb, DISCARD))
+                       ext4_issue_discard(sb, block_group, bit, count);
                ext4_lock_group(sb, block_group);
                mb_clear_bits(bitmap_bh->b_data, bit, count);
                mb_free_blocks(inode, &e4b, bit, count);
                ext4_mb_return_to_preallocation(inode, &e4b, block, count);
-               if (test_opt(sb, DISCARD))
-                       ext4_issue_discard(sb, block_group, bit, count);
        }
 
        ret = ext4_free_blks_count(sb, gdp) + count;