From 9b7aaa64f96f7ca280d75326fca42f42017b89ef Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Wed, 4 Dec 2013 16:58:19 -0500 Subject: dm thin: allow pool in read-only mode to transition to read-write mode A thin-pool may be in read-only mode because the pool's data or metadata space was exhausted. To allow for recovery, by adding more space to the pool, we must allow a pool to transition from PM_READ_ONLY to PM_WRITE mode. Otherwise, running out of space will render the pool permanently read-only. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 60bce43..8a30ad5 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1697,6 +1697,14 @@ void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd) up_write(&pmd->root_lock); } +void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd) +{ + down_write(&pmd->root_lock); + pmd->read_only = false; + dm_bm_set_read_write(pmd->bm); + up_write(&pmd->root_lock); +} + int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd, dm_block_t threshold, dm_sm_threshold_fn fn, diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h index 845ebbe..7bcc0e1 100644 --- a/drivers/md/dm-thin-metadata.h +++ b/drivers/md/dm-thin-metadata.h @@ -193,6 +193,7 @@ int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_siz * that nothing is changing. */ void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd); +void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd); int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd, dm_block_t threshold, diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 0d7852e..ee29037 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -1425,6 +1425,7 @@ static void set_pool_mode(struct pool *pool, enum pool_mode mode) break; case PM_WRITE: + dm_pool_metadata_read_write(pool->pmd); pool->process_bio = process_bio; pool->process_discard = process_discard; pool->process_prepared_mapping = process_prepared_mapping; @@ -1641,12 +1642,19 @@ static int bind_control_target(struct pool *pool, struct dm_target *ti) struct pool_c *pt = ti->private; /* - * We want to make sure that degraded pools are never upgraded. + * We want to make sure that a pool in PM_FAIL mode is never upgraded. */ enum pool_mode old_mode = pool->pf.mode; enum pool_mode new_mode = pt->adjusted_pf.mode; - if (old_mode > new_mode) + /* + * If we were in PM_FAIL mode, rollback of metadata failed. We're + * not going to recover without a thin_repair. So we never let the + * pool move out of the old mode. On the other hand a PM_READ_ONLY + * may have been due to a lack of metadata or data space, and may + * now work (ie. if the underlying devices have been resized). + */ + if (old_mode == PM_FAIL) new_mode = old_mode; pool->ti = ti; diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c index a7e8bf2..064a3c2 100644 --- a/drivers/md/persistent-data/dm-block-manager.c +++ b/drivers/md/persistent-data/dm-block-manager.c @@ -626,6 +626,12 @@ void dm_bm_set_read_only(struct dm_block_manager *bm) } EXPORT_SYMBOL_GPL(dm_bm_set_read_only); +void dm_bm_set_read_write(struct dm_block_manager *bm) +{ + bm->read_only = false; +} +EXPORT_SYMBOL_GPL(dm_bm_set_read_write); + u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor) { return crc32c(~(u32) 0, data, len) ^ init_xor; diff --git a/drivers/md/persistent-data/dm-block-manager.h b/drivers/md/persistent-data/dm-block-manager.h index 9a82083..13cd58e 100644 --- a/drivers/md/persistent-data/dm-block-manager.h +++ b/drivers/md/persistent-data/dm-block-manager.h @@ -108,9 +108,9 @@ int dm_bm_unlock(struct dm_block *b); int dm_bm_flush_and_unlock(struct dm_block_manager *bm, struct dm_block *superblock); - /* - * Request data be prefetched into the cache. - */ +/* + * Request data is prefetched into the cache. + */ void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b); /* @@ -125,6 +125,7 @@ void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b); * be returned if you do. */ void dm_bm_set_read_only(struct dm_block_manager *bm); +void dm_bm_set_read_write(struct dm_block_manager *bm); u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor); -- cgit v0.10.2