dm thin: fix discard support to a previously shared block
[deliverable/linux.git] / drivers / md / dm-thin.c
index 2c0cf511ec2385fa5a558b5d2e1e1ed0c874c9f6..51e656a3002c1b0184860631b38e63c551162095 100644 (file)
@@ -512,6 +512,7 @@ struct dm_thin_new_mapping {
        unsigned quiesced:1;
        unsigned prepared:1;
        unsigned pass_discard:1;
+       unsigned definitely_not_shared:1;
 
        struct thin_c *tc;
        dm_block_t virt_block;
@@ -640,7 +641,9 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m)
         */
        r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
        if (r) {
-               DMERR_LIMIT("dm_thin_insert_block() failed");
+               DMERR_LIMIT("%s: dm_thin_insert_block() failed: error = %d",
+                           dm_device_name(pool->pool_md), r);
+               set_pool_mode(pool, PM_READ_ONLY);
                cell_error(pool, m->cell);
                goto out;
        }
@@ -681,7 +684,15 @@ static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
        cell_defer_no_holder(tc, m->cell2);
 
        if (m->pass_discard)
-               remap_and_issue(tc, m->bio, m->data_block);
+               if (m->definitely_not_shared)
+                       remap_and_issue(tc, m->bio, m->data_block);
+               else {
+                       bool used = false;
+                       if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
+                               bio_endio(m->bio, 0);
+                       else
+                               remap_and_issue(tc, m->bio, m->data_block);
+               }
        else
                bio_endio(m->bio, 0);
 
@@ -749,13 +760,17 @@ static int ensure_next_mapping(struct pool *pool)
 
 static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
 {
-       struct dm_thin_new_mapping *r = pool->next_mapping;
+       struct dm_thin_new_mapping *m = pool->next_mapping;
 
        BUG_ON(!pool->next_mapping);
 
+       memset(m, 0, sizeof(struct dm_thin_new_mapping));
+       INIT_LIST_HEAD(&m->list);
+       m->bio = NULL;
+
        pool->next_mapping = NULL;
 
-       return r;
+       return m;
 }
 
 static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
@@ -767,15 +782,10 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
        struct pool *pool = tc->pool;
        struct dm_thin_new_mapping *m = get_next_mapping(pool);
 
-       INIT_LIST_HEAD(&m->list);
-       m->quiesced = 0;
-       m->prepared = 0;
        m->tc = tc;
        m->virt_block = virt_block;
        m->data_block = data_dest;
        m->cell = cell;
-       m->err = 0;
-       m->bio = NULL;
 
        if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
                m->quiesced = 1;
@@ -838,15 +848,12 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
        struct pool *pool = tc->pool;
        struct dm_thin_new_mapping *m = get_next_mapping(pool);
 
-       INIT_LIST_HEAD(&m->list);
        m->quiesced = 1;
        m->prepared = 0;
        m->tc = tc;
        m->virt_block = virt_block;
        m->data_block = data_block;
        m->cell = cell;
-       m->err = 0;
-       m->bio = NULL;
 
        /*
         * If the whole block of data is being overwritten or we are not
@@ -881,32 +888,23 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
        }
 }
 
-static int commit(struct pool *pool)
-{
-       int r;
-
-       r = dm_pool_commit_metadata(pool->pmd);
-       if (r)
-               DMERR_LIMIT("%s: commit failed: error = %d",
-                           dm_device_name(pool->pool_md), r);
-
-       return r;
-}
-
 /*
  * A non-zero return indicates read_only or fail_io mode.
  * Many callers don't care about the return value.
  */
-static int commit_or_fallback(struct pool *pool)
+static int commit(struct pool *pool)
 {
        int r;
 
        if (get_pool_mode(pool) != PM_WRITE)
                return -EINVAL;
 
-       r = commit(pool);
-       if (r)
+       r = dm_pool_commit_metadata(pool->pmd);
+       if (r) {
+               DMERR_LIMIT("%s: dm_pool_commit_metadata failed: error = %d",
+                           dm_device_name(pool->pool_md), r);
                set_pool_mode(pool, PM_READ_ONLY);
+       }
 
        return r;
 }
@@ -943,7 +941,9 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
                 * Try to commit to see if that will free up some
                 * more space.
                 */
-               (void) commit_or_fallback(pool);
+               r = commit(pool);
+               if (r)
+                       return r;
 
                r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
                if (r)
@@ -957,7 +957,7 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
                 * table reload).
                 */
                if (!free_blocks) {
-                       DMWARN("%s: no free space available.",
+                       DMWARN("%s: no free data space available.",
                               dm_device_name(pool->pool_md));
                        spin_lock_irqsave(&pool->lock, flags);
                        pool->no_free_space = 1;
@@ -967,8 +967,16 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
        }
 
        r = dm_pool_alloc_data_block(pool->pmd, result);
-       if (r)
+       if (r) {
+               if (r == -ENOSPC &&
+                   !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
+                   !free_blocks) {
+                       DMWARN("%s: no free metadata space available.",
+                              dm_device_name(pool->pool_md));
+                       set_pool_mode(pool, PM_READ_ONLY);
+               }
                return r;
+       }
 
        return 0;
 }
@@ -1037,12 +1045,12 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
                         */
                        m = get_next_mapping(pool);
                        m->tc = tc;
-                       m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown;
+                       m->pass_discard = pool->pf.discard_passdown;
+                       m->definitely_not_shared = !lookup_result.shared;
                        m->virt_block = block;
                        m->data_block = lookup_result.block;
                        m->cell = cell;
                        m->cell2 = cell2;
-                       m->err = 0;
                        m->bio = bio;
 
                        if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) {
@@ -1349,7 +1357,7 @@ static void process_deferred_bios(struct pool *pool)
        if (bio_list_empty(&bios) && !need_commit_due_to_time(pool))
                return;
 
-       if (commit_or_fallback(pool)) {
+       if (commit(pool)) {
                while ((bio = bio_list_pop(&bios)))
                        bio_io_error(bio);
                return;
@@ -1397,6 +1405,7 @@ static void set_pool_mode(struct pool *pool, enum pool_mode mode)
        case PM_FAIL:
                DMERR("%s: switching pool to failure mode",
                      dm_device_name(pool->pool_md));
+               dm_pool_metadata_read_only(pool->pmd);
                pool->process_bio = process_bio_fail;
                pool->process_discard = process_bio_fail;
                pool->process_prepared_mapping = process_prepared_mapping_fail;
@@ -1421,6 +1430,7 @@ 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;
@@ -1637,12 +1647,19 @@ 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;
@@ -2266,7 +2283,7 @@ static int pool_preresume(struct dm_target *ti)
                return r;
 
        if (need_commit1 || need_commit2)
-               (void) commit_or_fallback(pool);
+               (void) commit(pool);
 
        return 0;
 }
@@ -2293,7 +2310,7 @@ static void pool_postsuspend(struct dm_target *ti)
 
        cancel_delayed_work(&pool->waker);
        flush_workqueue(pool->wq);
-       (void) commit_or_fallback(pool);
+       (void) commit(pool);
 }
 
 static int check_arg_count(unsigned argc, unsigned args_required)
@@ -2427,7 +2444,7 @@ static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct
        if (r)
                return r;
 
-       (void) commit_or_fallback(pool);
+       (void) commit(pool);
 
        r = dm_pool_reserve_metadata_snap(pool->pmd);
        if (r)
@@ -2489,7 +2506,7 @@ static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
                DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
 
        if (!r)
-               (void) commit_or_fallback(pool);
+               (void) commit(pool);
 
        return r;
 }
@@ -2544,7 +2561,7 @@ static void pool_status(struct dm_target *ti, status_type_t type,
 
                /* Commit to ensure statistics aren't out-of-date */
                if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
-                       (void) commit_or_fallback(pool);
+                       (void) commit(pool);
 
                r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
                if (r) {
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