diff options
| -rw-r--r-- | drivers/md/dm-table.c | 35 | ||||
| -rw-r--r-- | drivers/md/dm.c | 15 | ||||
| -rw-r--r-- | drivers/md/dm.h | 1 |
3 files changed, 50 insertions, 1 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 77b90ae6699..100368eb799 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1212,6 +1212,41 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector) return &t->targets[(KEYS_PER_NODE * n) + k]; } +static int count_device(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *data) +{ + unsigned *num_devices = data; + + (*num_devices)++; + + return 0; +} + +/* + * Check whether a table has no data devices attached using each + * target's iterate_devices method. + * Returns false if the result is unknown because a target doesn't + * support iterate_devices. + */ +bool dm_table_has_no_data_devices(struct dm_table *table) +{ + struct dm_target *uninitialized_var(ti); + unsigned i = 0, num_devices = 0; + + while (i < dm_table_get_num_targets(table)) { + ti = dm_table_get_target(table, i++); + + if (!ti->type->iterate_devices) + return false; + + ti->type->iterate_devices(ti, count_device, &num_devices); + if (num_devices) + return false; + } + + return true; +} + /* * Establish the new table's queue_limits and validate them. */ diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 6748e0c4df1..67ffa391edc 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2429,7 +2429,7 @@ static void dm_queue_flush(struct mapped_device *md) */ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) { - struct dm_table *map = ERR_PTR(-EINVAL); + struct dm_table *live_map, *map = ERR_PTR(-EINVAL); struct queue_limits limits; int r; @@ -2439,6 +2439,19 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) if (!dm_suspended_md(md)) goto out; + /* + * If the new table has no data devices, retain the existing limits. + * This helps multipath with queue_if_no_path if all paths disappear, + * then new I/O is queued based on these limits, and then some paths + * reappear. + */ + if (dm_table_has_no_data_devices(table)) { + live_map = dm_get_live_table(md); + if (live_map) + limits = md->queue->limits; + dm_table_put(live_map); + } + r = dm_calculate_queue_limits(table, &limits); if (r) { map = ERR_PTR(r); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 52eef493d26..6a99fefaa74 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -54,6 +54,7 @@ void dm_table_event_callback(struct dm_table *t, void (*fn)(void *), void *context); struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index); struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector); +bool dm_table_has_no_data_devices(struct dm_table *table); int dm_calculate_queue_limits(struct dm_table *table, struct queue_limits *limits); void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, |