2 files changed, 32 insertions, 6 deletions

diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt
index 50c44cf79b0e..8a7a3d46e0da 100644
--- a/Documentation/device-mapper/thin-provisioning.txt
+++ b/Documentation/device-mapper/thin-provisioning.txt
@@ -235,6 +235,8 @@ i) Constructor
       read_only: Don't allow any changes to be made to the pool
                  metadata.
 
+      error_if_no_space: Error IOs, instead of queueing, if no space.
+
     Data block size must be between 64KB (128 sectors) and 1GB
     (2097152 sectors) inclusive.
 
@@ -276,6 +278,11 @@ ii) Status
         contain the string 'Fail'.  The userspace recovery tools
         should then be used.
 
+    error_if_no_space|queue_if_no_space
+        If the pool runs out of data or metadata space, the pool will
+        either queue or error the IO destined to the data device.  The
+        default is to queue the IO until more space is added.
+
 iii) Messages
 
     create_thin <dev id>
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 53252d2af249..075c39edea21 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -144,6 +144,7 @@ struct pool_features {
         bool zero_new_blocks:1;
         bool discard_enabled:1;
         bool discard_passdown:1;
+        bool error_if_no_space:1;
 };
 
 struct thin_c;
@@ -1440,6 +1441,9 @@ static void set_no_free_space(struct pool *pool)
 {
         unsigned long flags;
 
+        if (pool->pf.error_if_no_space)
+                return;
+
         spin_lock_irqsave(&pool->lock, flags);
         pool->no_free_space = true;
         spin_unlock_irqrestore(&pool->lock, flags);
@@ -1723,6 +1727,7 @@ static void pool_features_init(struct pool_features *pf)
         pf->zero_new_blocks = true;
         pf->discard_enabled = true;
         pf->discard_passdown = true;
+        pf->error_if_no_space = false;
 }
 
 static void __pool_destroy(struct pool *pool)
@@ -1968,6 +1973,9 @@ static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
                 else if (!strcasecmp(arg_name, "read_only"))
                         pf->mode = PM_READ_ONLY;
 
+                else if (!strcasecmp(arg_name, "error_if_no_space"))
+                        pf->error_if_no_space = true;
+
                 else {
                         ti->error = "Unrecognised pool feature requested";
                         r = -EINVAL;
@@ -2038,6 +2046,8 @@ static dm_block_t calc_metadata_threshold(struct pool_c *pt)
  *           skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
  *           ignore_discard: disable discard
  *           no_discard_passdown: don't pass discards down to the data device
+ *           read_only: Don't allow any changes to be made to the pool metadata.
+ *           error_if_no_space: error IOs, instead of queueing, if no space.
  */
 static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
 {
@@ -2555,7 +2565,8 @@ static void emit_flags(struct pool_features *pf, char *result,
                        unsigned sz, unsigned maxlen)
 {
         unsigned count = !pf->zero_new_blocks + !pf->discard_enabled +
-                !pf->discard_passdown + (pf->mode == PM_READ_ONLY);
+                !pf->discard_passdown + (pf->mode == PM_READ_ONLY) +
+                pf->error_if_no_space;
         DMEMIT("%u ", count);
 
         if (!pf->zero_new_blocks)
@@ -2569,6 +2580,9 @@ static void emit_flags(struct pool_features *pf, char *result,
 
         if (pf->mode == PM_READ_ONLY)
                 DMEMIT("read_only ");
+
+        if (pf->error_if_no_space)
+                DMEMIT("error_if_no_space ");
 }
 
 /*
@@ -2663,11 +2677,16 @@ static void pool_status(struct dm_target *ti, status_type_t type,
                         DMEMIT("rw ");
 
                 if (!pool->pf.discard_enabled)
-                        DMEMIT("ignore_discard");
+                        DMEMIT("ignore_discard ");
                 else if (pool->pf.discard_passdown)
-                        DMEMIT("discard_passdown");
+                        DMEMIT("discard_passdown ");
+                else
+                        DMEMIT("no_discard_passdown ");
+
+                if (pool->pf.error_if_no_space)
+                        DMEMIT("error_if_no_space ");
                 else
-                        DMEMIT("no_discard_passdown");
+                        DMEMIT("queue_if_no_space ");
 
                 break;
 
@@ -2766,7 +2785,7 @@ static struct target_type pool_target = {
         .name = "thin-pool",
         .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
                     DM_TARGET_IMMUTABLE,
-        .version = {1, 9, 0},
+        .version = {1, 10, 0},
         .module = THIS_MODULE,
         .ctr = pool_ctr,
         .dtr = pool_dtr,
@@ -3053,7 +3072,7 @@ static int thin_iterate_devices(struct dm_target *ti,
 
 static struct target_type thin_target = {
         .name = "thin",
-        .version = {1, 9, 0},
+        .version = {1, 10, 0},
         .module = THIS_MODULE,
         .ctr = thin_ctr,
         .dtr = thin_dtr,