From: Liu Bo bo.li.liu@oracle.com
[ Upstream commit 7583d8d088ff2c323b1d4f15b191ca2c23d32558 ]
Before rbio_orig_end_io() goes to free rbio, rbio may get merged with more bios from other rbios and rbio->bio_list becomes non-empty, in that case, these newly merged bios don't end properly.
Once unlock_stripe() is done, rbio->bio_list will not be updated any more and we can call bio_endio() on all queued bios.
It should only happen in error-out cases, the normal path of recover and full stripe write have already set RBIO_RMW_LOCKED_BIT to disable merge before doing IO, so rbio_orig_end_io() called by them doesn't have the above issue.
Reported-by: Jérôme Carretero cJ-ko@zougloub.eu Signed-off-by: Liu Bo bo.li.liu@oracle.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- fs/btrfs/raid56.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c index 025e69c57cbd..19e12964aa6d 100644 --- a/fs/btrfs/raid56.c +++ b/fs/btrfs/raid56.c @@ -858,10 +858,17 @@ static void __free_raid_bio(struct btrfs_raid_bio *rbio) kfree(rbio); }
-static void free_raid_bio(struct btrfs_raid_bio *rbio) +static void rbio_endio_bio_list(struct bio *cur, blk_status_t err) { - unlock_stripe(rbio); - __free_raid_bio(rbio); + struct bio *next; + + while (cur) { + next = cur->bi_next; + cur->bi_next = NULL; + cur->bi_status = err; + bio_endio(cur); + cur = next; + } }
/* @@ -871,20 +878,26 @@ static void free_raid_bio(struct btrfs_raid_bio *rbio) static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err) { struct bio *cur = bio_list_get(&rbio->bio_list); - struct bio *next; + struct bio *extra;
if (rbio->generic_bio_cnt) btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
- free_raid_bio(rbio); + /* + * At this moment, rbio->bio_list is empty, however since rbio does not + * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the + * hash list, rbio may be merged with others so that rbio->bio_list + * becomes non-empty. + * Once unlock_stripe() is done, rbio->bio_list will not be updated any + * more and we can call bio_endio() on all queued bios. + */ + unlock_stripe(rbio); + extra = bio_list_get(&rbio->bio_list); + __free_raid_bio(rbio);
- while (cur) { - next = cur->bi_next; - cur->bi_next = NULL; - cur->bi_status = err; - bio_endio(cur); - cur = next; - } + rbio_endio_bio_list(cur, err); + if (extra) + rbio_endio_bio_list(extra, err); }
/*