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[5/6] btrfs: remove BUG_ON() after splitting leaf

Message ID 966e008cdf776b803b96a87756aa58917212a0c6.1638440535.git.fdmanana@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: optimize btree insertions and some cleanups | expand

Commit Message

Filipe Manana Dec. 2, 2021, 10:30 a.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

After calling split_leaf() we BUG_ON() if the returned value is greater
than zero. However split_leaf() only returns 0, in case of success, or a
negative value in case of an error.

The reason for the BUG_ON() is that if we ever get a positive return
value from split_leaf(), we can not simply propagate it to the callers
of btrfs_search_slot(), as that would be interpreted as "key not found"
and not as an error. That means it could result in callers ending up
causing some potential silent corruption.

So change the BUG_ON() to an ASSERT(), and in case assertions are
disabled, produce a warning and set the return value to an error, to make
it not possible to get into a silent corruption and having the error not
noticed.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/ctree.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
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Patch

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 15357274a0c4..bcf99c787d68 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1817,7 +1817,9 @@  static int search_leaf(struct btrfs_trans_handle *trans,
 
 			err = split_leaf(trans, root, key, path, ins_len,
 					 (ret == 0));
-			BUG_ON(err > 0);
+			ASSERT(err <= 0);
+			if (WARN_ON(err > 0))
+				err = -EUCLEAN;
 			if (err)
 				ret = err;
 		}