In log_writes_map(), when a discard bio is received and the device does not support discard, a pending block is allocated and its pending_blocks refcount is incremented, but the block is never freed. The function calls bio_endio(bio) and returns DM_MAPIO_SUBMITTED directly, bypassing normal_end_io() which would enqueue the block for later release via the kthread. As a result, the refcount for the associated pending block is leaked, and pending_blocks never reaches zero, preventing log_writes_dtr() from completing and causing the device destruction to hang.
Free the block with free_pending_block() before completing the bio in the !device_supports_discard path, matching the error handling done when page allocation fails. Cc: [email protected] Fixes: 0e9cebe72459 ("dm: add log writes target") Signed-off-by: Wentao Liang <[email protected]> --- drivers/md/dm-log-writes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c index c72e07c3f5a0..05133b1553ca 100644 --- a/drivers/md/dm-log-writes.c +++ b/drivers/md/dm-log-writes.c @@ -709,6 +709,8 @@ static int log_writes_map(struct dm_target *ti, struct bio *bio) WARN_ON(flush_bio || fua_bio); if (lc->device_supports_discard) goto map_bio; + free_pending_block(lc, block); + pb->block = NULL; bio_endio(bio); return DM_MAPIO_SUBMITTED; } -- 2.34.1
