From 15b94a690470038aa08247eedbebbe7e2218d5ee Mon Sep 17 00:00:00 2001 From: Junichi Nomura Date: Fri, 29 May 2015 08:51:03 +0000 Subject: [PATCH] dm: fix reload failure of 0 path multipath mapping on blk-mq devices dm-multipath accepts 0 path mapping. # echo '0 2097152 multipath 0 0 0 0' | dmsetup create newdev Such a mapping can be used to release underlying devices while still holding requests in its queue until working paths come back. However, once the multipath device is created over blk-mq devices, it rejects reloading of 0 path mapping: # echo '0 2097152 multipath 0 0 1 1 queue-length 0 1 1 /dev/sda 1' \ | dmsetup create mpath1 # echo '0 2097152 multipath 0 0 0 0' | dmsetup load mpath1 device-mapper: reload ioctl on mpath1 failed: Invalid argument Command failed With following kernel message: device-mapper: ioctl: can't change device type after initial table load. DM tries to inherit the current table type using dm_table_set_type() but it doesn't work as expected because of unnecessary check about whether the target type is hybrid or not. Hybrid type is for targets that work as either request-based or bio-based and not required for blk-mq or non blk-mq checking. Fixes: 65803c205983 ("dm table: train hybrid target type detection to select blk-mq if appropriate") Signed-off-by: Jun'ichi Nomura Signed-off-by: Mike Snitzer --- drivers/md/dm-table.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index d9b00b8565c6..16ba55ad7089 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -820,6 +820,12 @@ void dm_consume_args(struct dm_arg_set *as, unsigned num_args) } EXPORT_SYMBOL(dm_consume_args); +static bool __table_type_request_based(unsigned table_type) +{ + return (table_type == DM_TYPE_REQUEST_BASED || + table_type == DM_TYPE_MQ_REQUEST_BASED); +} + static int dm_table_set_type(struct dm_table *t) { unsigned i; @@ -852,8 +858,7 @@ static int dm_table_set_type(struct dm_table *t) * Determine the type from the live device. * Default to bio-based if device is new. */ - if (live_md_type == DM_TYPE_REQUEST_BASED || - live_md_type == DM_TYPE_MQ_REQUEST_BASED) + if (__table_type_request_based(live_md_type)) request_based = 1; else bio_based = 1; @@ -903,7 +908,7 @@ static int dm_table_set_type(struct dm_table *t) } t->type = DM_TYPE_MQ_REQUEST_BASED; - } else if (hybrid && list_empty(devices) && live_md_type != DM_TYPE_NONE) { + } else if (list_empty(devices) && __table_type_request_based(live_md_type)) { /* inherit live MD type */ t->type = live_md_type; @@ -925,10 +930,7 @@ struct target_type *dm_table_get_immutable_target_type(struct dm_table *t) bool dm_table_request_based(struct dm_table *t) { - unsigned table_type = dm_table_get_type(t); - - return (table_type == DM_TYPE_REQUEST_BASED || - table_type == DM_TYPE_MQ_REQUEST_BASED); + return __table_type_request_based(dm_table_get_type(t)); } bool dm_table_mq_request_based(struct dm_table *t) -- 2.20.1