Merge tag 'dm-3.19-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "One stable fix for a dm-cache 3.19-rc6 regression and one stable fix
  for dm-thin:

   - fix DM cache metadata open/lookup error paths to properly use
     ERR_PTR and IS_ERR (fixes: 3.19-rc6 "stable" commit 9b1cc9f251)

   - fix DM thin-provisioning to disallow userspace from sending
     messages to the thin-pool if the pool is in READ_ONLY or FAIL mode
     since no metadata changes are allowed in these modes"

* tag 'dm-3.19-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm thin: don't allow messages to be sent to a pool target in READ_ONLY or FAIL mode
  dm cache: fix missing ERR_PTR returns and handling

2 files changed, 11 insertions, 4 deletions

diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 21b156242e42..c1c010498a21 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -683,7 +683,7 @@ static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
         cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
         if (!cmd) {
                 DMERR("could not allocate metadata struct");
-                return NULL;
+                return ERR_PTR(-ENOMEM);
         }
 
         atomic_set(&cmd->ref_count, 1);
@@ -745,7 +745,7 @@ static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
                 return cmd;
 
         cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
-        if (cmd) {
+        if (!IS_ERR(cmd)) {
                 mutex_lock(&table_lock);
                 cmd2 = lookup(bdev);
                 if (cmd2) {
@@ -780,9 +780,10 @@ struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
 {
         struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
                                                        may_format_device, policy_hint_size);
-        if (cmd && !same_params(cmd, data_block_size)) {
+
+        if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
                 dm_cache_metadata_close(cmd);
-                return NULL;
+                return ERR_PTR(-EINVAL);
         }
 
         return cmd;
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 493478989dbd..07705ee181e3 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3385,6 +3385,12 @@ static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
         struct pool_c *pt = ti->private;
         struct pool *pool = pt->pool;
 
+        if (get_pool_mode(pool) >= PM_READ_ONLY) {
+                DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
+                      dm_device_name(pool->pool_md));
+                return -EINVAL;
+        }
+
         if (!strcasecmp(argv[0], "create_thin"))
                 r = process_create_thin_mesg(argc, argv, pool);