From: Mikulas Patocka <mpatocka@xxxxxxxxxx> [ Upstream commit 873937e75f9a8ea231a502c3d29d9cb6ad91b3ef ] The existing code allows changing the data device when the thin-pool target is reloaded. This capability is not required and only complicates device lifetime guarantees. This can cause crashes like the one reported here: https://bugzilla.redhat.com/show_bug.cgi?id=1788596 where the kernel tries to issue a flush bio located in a structure that was already freed. Take the first step to simplifying the thin-pool's data device lifetime by disallowing changing it. Like the thin-pool's metadata device, the data device is now set in pool_create() and it cannot be changed for a given thin-pool. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/md/dm-thin.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index a2bb2622cdbd5..4fb6e89c87862 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -231,6 +231,7 @@ struct pool { struct dm_target *ti; /* Only set if a pool target is bound */ struct mapped_device *pool_md; + struct block_device *data_dev; struct block_device *md_dev; struct dm_pool_metadata *pmd; @@ -2933,6 +2934,7 @@ static struct kmem_cache *_new_mapping_cache; static struct pool *pool_create(struct mapped_device *pool_md, struct block_device *metadata_dev, + struct block_device *data_dev, unsigned long block_size, int read_only, char **error) { @@ -3040,6 +3042,7 @@ static struct pool *pool_create(struct mapped_device *pool_md, pool->last_commit_jiffies = jiffies; pool->pool_md = pool_md; pool->md_dev = metadata_dev; + pool->data_dev = data_dev; __pool_table_insert(pool); return pool; @@ -3081,6 +3084,7 @@ static void __pool_dec(struct pool *pool) static struct pool *__pool_find(struct mapped_device *pool_md, struct block_device *metadata_dev, + struct block_device *data_dev, unsigned long block_size, int read_only, char **error, int *created) { @@ -3091,19 +3095,23 @@ static struct pool *__pool_find(struct mapped_device *pool_md, *error = "metadata device already in use by a pool"; return ERR_PTR(-EBUSY); } + if (pool->data_dev != data_dev) { + *error = "data device already in use by a pool"; + return ERR_PTR(-EBUSY); + } __pool_inc(pool); } else { pool = __pool_table_lookup(pool_md); if (pool) { - if (pool->md_dev != metadata_dev) { + if (pool->md_dev != metadata_dev || pool->data_dev != data_dev) { *error = "different pool cannot replace a pool"; return ERR_PTR(-EINVAL); } __pool_inc(pool); } else { - pool = pool_create(pool_md, metadata_dev, block_size, read_only, error); + pool = pool_create(pool_md, metadata_dev, data_dev, block_size, read_only, error); *created = 1; } } @@ -3356,7 +3364,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) goto out; } - pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, + pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, data_dev->bdev, block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created); if (IS_ERR(pool)) { r = PTR_ERR(pool); @@ -4098,7 +4106,7 @@ static struct target_type pool_target = { .name = "thin-pool", .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | DM_TARGET_IMMUTABLE, - .version = {1, 21, 0}, + .version = {1, 22, 0}, .module = THIS_MODULE, .ctr = pool_ctr, .dtr = pool_dtr, @@ -4475,7 +4483,7 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) static struct target_type thin_target = { .name = "thin", - .version = {1, 21, 0}, + .version = {1, 22, 0}, .module = THIS_MODULE, .ctr = thin_ctr, .dtr = thin_dtr, -- 2.20.1 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
