Otherwise, blk_validate_limits() will throw-away the max_sectors that was stacked from underlying device(s). In doing so it can set a max_sectors limit that violates underlying device limits.
This caused dm-multipath IO failures like the following because the underlying devices' max_sectors were stacked up to be 1024, yet blk_validate_limits() defaulted max_sectors to BLK_DEF_MAX_SECTORS_CAP (2560): [ 1214.673233] blk_insert_cloned_request: over max size limit. (2048 > 1024) [ 1214.673267] device-mapper: multipath: 254:3: Failing path 8:32. [ 1214.675196] blk_insert_cloned_request: over max size limit. (2048 > 1024) [ 1214.675224] device-mapper: multipath: 254:3: Failing path 8:16. [ 1214.675309] blk_insert_cloned_request: over max size limit. (2048 > 1024) [ 1214.675338] device-mapper: multipath: 254:3: Failing path 8:48. [ 1214.675413] blk_insert_cloned_request: over max size limit. (2048 > 1024) [ 1214.675441] device-mapper: multipath: 254:3: Failing path 8:64. The initial bug report included: [ 13.822701] blk_insert_cloned_request: over max size limit. (248 > 128) [ 13.829351] device-mapper: multipath: 253:3: Failing path 8:32. [ 13.835307] blk_insert_cloned_request: over max size limit. (248 > 128) [ 13.841928] device-mapper: multipath: 253:3: Failing path 65:16. [ 13.844532] blk_insert_cloned_request: over max size limit. (248 > 128) [ 13.854363] blk_insert_cloned_request: over max size limit. (248 > 128) [ 13.854580] device-mapper: multipath: 253:4: Failing path 8:48. [ 13.861166] device-mapper: multipath: 253:3: Failing path 8:192. Reported-by: Marco Patalano <[email protected]> Reported-by: Ewan Milne <[email protected]> Fixes: 1c0e720228ad ("dm: use queue_limits_set") Signed-off-by: Mike Snitzer <[email protected]> --- drivers/md/dm-table.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 88114719fe18..6463b4afeaa4 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1961,6 +1961,7 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, struct queue_limits *limits) { bool wc = false, fua = false; + unsigned int max_hw_sectors; int r; if (dm_table_supports_nowait(t)) @@ -1981,9 +1982,16 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, if (!dm_table_supports_secure_erase(t)) limits->max_secure_erase_sectors = 0; + /* Don't allow queue_limits_set() to throw-away stacked max_sectors */ + max_hw_sectors = limits->max_hw_sectors; + limits->max_hw_sectors = limits->max_sectors; r = queue_limits_set(q, limits); if (r) return r; + /* Restore stacked max_hw_sectors */ + mutex_lock(&q->limits_lock); + limits->max_hw_sectors = max_hw_sectors; + mutex_unlock(&q->limits_lock); if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) { wc = true; -- 2.43.0
