diff options
authorMing Lei <>2016-04-15 18:51:28 +0800
committerJens Axboe <>2016-04-15 08:25:56 -0600
commita7297a6a3a3322b054592e8e988981d2f5f29cc4 (patch)
parenta5229050b69cfffb690b546c357ca5a60434c0c8 (diff)
block: loop: fix filesystem corruption in case of aio/dio
Starting from commit e36f620428(block: split bios to max possible length), block core starts to split bio in the middle of bvec. Unfortunately loop dio/aio doesn't consider this situation, and always treat 'iter.iov_offset' as zero. Then filesystem corruption is observed. This patch figures out the offset of the base bvevc via 'bio->bi_iter.bi_bvec_done' and fixes the issue by passing the offset to iov iterator. Fixes: e36f6204288088f (block: split bios to max possible length) Cc: Keith Busch <> Cc: Al Viro <> Cc: (4.5) Signed-off-by: Ming Lei <> Signed-off-by: Jens Axboe <>
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 423f4ca7d712..80cf8add46ff 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -488,6 +488,12 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
iov_iter_bvec(&iter, ITER_BVEC | rw, bvec,
bio_segments(bio), blk_rq_bytes(cmd->rq));
+ /*
+ * This bio may be started from the middle of the 'bvec'
+ * because of bio splitting, so offset from the bvec must
+ * be passed to iov iterator
+ */
+ iter.iov_offset = bio->bi_iter.bi_bvec_done;
cmd->iocb.ki_pos = pos;
cmd->iocb.ki_filp = file;