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From:   Dmitry Monakhov <dmonakhov@gmail.com>
To:     linux-ext4@vger.kernel.org
Cc:     tytso@mit.edu, Dmitry Monakhov <dmonakhov@gmail.com>
Subject: [PATCH] ext4: mark block bitmap corrupted when found instead of BUGON
Date:   Tue, 10 Mar 2020 15:01:56 +0000
Message-Id: <20200310150156.641-1-dmonakhov@gmail.com>
Sender: linux-ext4-owner@vger.kernel.org
Precedence: bulk

We already has similar code in ext4_mb_complex_scan_group(), but
ext4_mb_simple_scan_group() still affected.

Other reports: https://www.spinics.net/lists/linux-ext4/msg60231.html

Signed-off-by: Dmitry Monakhov <dmonakhov@gmail.com>
---
 fs/ext4/mballoc.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 1027e01..97cd1a2 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1901,8 +1901,15 @@ void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
 		BUG_ON(buddy == NULL);
 
 		k = mb_find_next_zero_bit(buddy, max, 0);
-		BUG_ON(k >= max);
-
+		if (k >= max) {
+			ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0,
+				"%d free clusters of order %d. But found 0",
+				grp->bb_counters[i], i);
+			ext4_mark_group_bitmap_corrupted(ac->ac_sb,
+					 e4b->bd_group,
+					EXT4_GROUP_INFO_BBITMAP_CORRUPT);
+			break;
+		}
 		ac->ac_found++;
 
 		ac->ac_b_ex.fe_len = 1 << i;
-- 
2.7.4