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 <[email protected]> Tested-by: Zdenek Kabelac <[email protected]> Cc: [email protected] --- block/blk-lib.c | 10 ++++++++++ 1 file changed, 10 insertions(+) Index: linux-2.6/block/blk-lib.c =================================================================== --- linux-2.6.orig/block/blk-lib.c 2018-06-18 01:08:49.500000000 +0200 +++ linux-2.6/block/blk-lib.c 2018-06-29 20:09:27.670000000 +0200 @@ -68,6 +68,8 @@ int __blkdev_issue_discard(struct block_ */ 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_ *biop = bio; return 0; + +fail: + if (bio) { + submit_bio_wait(bio); + bio_put(bio); + } + *biop = NULL; + return -EOPNOTSUPP; } EXPORT_SYMBOL(__blkdev_issue_discard); -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
