ext4: avoid allocating blocks from corrupted group in ext4_mb_find_by_goal()

Places the logic for checking if the group's block bitmap is corrupt under
the protection of the group lock to avoid allocating blocks from the group
with a corrupted block bitmap.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240104142040.2835097-8-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 82afe275e6c88f80cc4c2ccaed54d04be7273629..2069d768c619881810d7c65bca6a2147c54c7a24 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2336,12 +2336,10 @@ int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
        if (err)
                return err;
 
-       if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
-               ext4_mb_unload_buddy(e4b);
-               return 0;
-       }
-
        ext4_lock_group(ac->ac_sb, group);
+       if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
+               goto out;
+
        max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
                             ac->ac_g_ex.fe_len, &ex);
        ex.fe_logical = 0xDEADFA11; /* debug value */
@@ -2374,6 +2372,7 @@ int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
                ac->ac_b_ex = ex;
                ext4_mb_use_best_found(ac, e4b);
        }
+out:
        ext4_unlock_group(ac->ac_sb, group);
        ext4_mb_unload_buddy(e4b);