Discard is a special type of request that can have non-contiguous bios. Imagine we have a request with starting sector 0 and length 1024, so read or write means [0, 1024) range in the file. For discard this request can have 2 bios [0, 512) and [1024, 1536), but we always discarded [0, 1024). Set max_discard_segments to 1 to avoid such merges.
https://virtuozzo.atlassian.net/browse/VSTOR-154159 Fixes: 6ddad5a4d226 ("dm-ploop: Add ploop target driver") Feature: dm-ploop: ploop target driver Signed-off-by: Andrey Zhadchenko <[email protected]> --- drivers/md/dm-ploop-target.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c index d8279c79ef56d..b1f502d664447 100644 --- a/drivers/md/dm-ploop-target.c +++ b/drivers/md/dm-ploop-target.c @@ -661,6 +661,7 @@ static void ploop_io_hints(struct dm_target *ti, struct queue_limits *limits) limits->max_hw_discard_sectors = CLU_TO_SEC(ploop, 1); limits->discard_granularity = CLU_SIZE(ploop); limits->discard_alignment = 0; + limits->max_discard_segments = 1; limits->fua = BLK_NO_FUA; } -- 2.43.5 _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
