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authorMikulas Patocka <mpatocka@redhat.com>2018-07-03 13:34:22 -0400
committerJens Axboe <axboe@kernel.dk>2018-07-09 09:07:54 -0600
commitb88aef36b87c9787a4db724923ec4f57dfd513f3 (patch)
tree9d493ac5c131c41f719877fb632493d99b6614e7 /block/blk-lib.c
parentc137969bd4c5b2a67803d10518e3d60d3b13d0cb (diff)
downloadlwn-b88aef36b87c9787a4db724923ec4f57dfd513f3.tar.gz
lwn-b88aef36b87c9787a4db724923ec4f57dfd513f3.zip
block: fix infinite loop if the device loses discard capability
If __blkdev_issue_discard is in progress and a device mapper device is reloaded with a table that doesn't support discard, q->limits.max_discard_sectors is set to zero. This results in infinite loop in __blkdev_issue_discard. This patch checks if max_discard_sectors is zero and aborts with -EOPNOTSUPP. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Tested-by: Zdenek Kabelac <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-lib.c')
-rw-r--r--block/blk-lib.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 8faa70f26fcd..d1b9dd03da25 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -68,6 +68,8 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
*/
req_sects = min_t(sector_t, nr_sects,
q->limits.max_discard_sectors);
+ if (!req_sects)
+ goto fail;
if (req_sects > UINT_MAX >> 9)
req_sects = UINT_MAX >> 9;
@@ -105,6 +107,14 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
*biop = bio;
return 0;
+
+fail:
+ if (bio) {
+ submit_bio_wait(bio);
+ bio_put(bio);
+ }
+ *biop = NULL;
+ return -EOPNOTSUPP;
}
EXPORT_SYMBOL(__blkdev_issue_discard);