dm thin: add error_if_no_space feature

[deliverable/linux.git] / drivers / md / dm-thin.c

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 53252d2af2496aec75e15a6c6bf4a83bc4572f3c..075c39edea21f04f35e7b04f694ae96073dfc27b 100644 (file)
--- 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,