dm thin: refactor data dev resize

Refactor device size functions in preparation for similar metadata
device resizing functions.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 00cee02f8fc9b299788941c9b4147abdfc56c83c..9452a489ed999d765211579c3d93fc4f4f8f8c91 100644 (file)
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -1645,12 +1645,12 @@ int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
        return r;
 }
 
-static int __resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
+static int __resize_space_map(struct dm_space_map *sm, dm_block_t new_count)
 {
        int r;
        dm_block_t old_count;
 
-       r = dm_sm_get_nr_blocks(pmd->data_sm, &old_count);
+       r = dm_sm_get_nr_blocks(sm, &old_count);
        if (r)
                return r;
 
@@ -1658,11 +1658,11 @@ static int __resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
                return 0;
 
        if (new_count < old_count) {
-               DMERR("cannot reduce size of data device");
+               DMERR("cannot reduce size of space map");
                return -EINVAL;
        }
 
-       return dm_sm_extend(pmd->data_sm, new_count - old_count);
+       return dm_sm_extend(sm, new_count - old_count);
 }
 
 int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
@@ -1671,7 +1671,7 @@ int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_count)
 
        down_write(&pmd->root_lock);
        if (!pmd->fail_io)
-               r = __resize_data_dev(pmd, new_count);
+               r = __resize_space_map(pmd->data_sm, new_count);
        up_write(&pmd->root_lock);
 
        return r;

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 004ad1652b73477dae0194b957842434cf48c38d..111c148fb1d031445f1cca2f73a3d3616823eeb6 100644 (file)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -922,7 +922,7 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
                return r;
 
        if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
-               DMWARN("%s: reached low water mark, sending event.",
+               DMWARN("%s: reached low water mark for data device: sending event.",
                       dm_device_name(pool->pool_md));
                spin_lock_irqsave(&pool->lock, flags);
                pool->low_water_triggered = 1;
@@ -1909,6 +1909,20 @@ static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
        return r;
 }
 
+static sector_t get_metadata_dev_size(struct block_device *bdev)
+{
+       sector_t metadata_dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+       char buffer[BDEVNAME_SIZE];
+
+       if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) {
+               DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
+                      bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
+               metadata_dev_size = THIN_METADATA_MAX_SECTORS_WARNING;
+       }
+
+       return metadata_dev_size;
+}
+
 /*
  * thin-pool <metadata dev> <data dev>
  *          <data block size (sectors)>
@@ -1931,8 +1945,6 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
        unsigned long block_size;
        dm_block_t low_water_blocks;
        struct dm_dev *metadata_dev;
-       sector_t metadata_dev_size;
-       char b[BDEVNAME_SIZE];
 
        /*
         * FIXME Remove validation from scope of lock.
@@ -1953,10 +1965,11 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
                goto out_unlock;
        }
 
-       metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
-       if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
-               DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
-                      bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
+       /*
+        * Run for the side-effect of possibly issuing a warning if the
+        * device is too big.
+        */
+       (void) get_metadata_dev_size(metadata_dev->bdev);
 
        r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
        if (r) {
@@ -2079,18 +2092,7 @@ static int pool_map(struct dm_target *ti, struct bio *bio)
        return r;
 }
 
-/*
- * Retrieves the number of blocks of the data device from
- * the superblock and compares it to the actual device size,
- * thus resizing the data device in case it has grown.
- *
- * This both copes with opening preallocated data devices in the ctr
- * being followed by a resume
- * -and-
- * calling the resume method individually after userspace has
- * grown the data device in reaction to a table event.
- */
-static int pool_preresume(struct dm_target *ti)
+static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
 {
        int r;
        struct pool_c *pt = ti->private;
@@ -2098,12 +2100,7 @@ static int pool_preresume(struct dm_target *ti)
        sector_t data_size = ti->len;
        dm_block_t sb_data_size;
 
-       /*
-        * Take control of the pool object.
-        */
-       r = bind_control_target(pool, ti);
-       if (r)
-               return r;
+       *need_commit = false;
 
        (void) sector_div(data_size, pool->sectors_per_block);
 
@@ -2114,7 +2111,7 @@ static int pool_preresume(struct dm_target *ti)
        }
 
        if (data_size < sb_data_size) {
-               DMERR("pool target too small, is %llu blocks (expected %llu)",
+               DMERR("pool target (%llu blocks) too small: expected %llu",
                      (unsigned long long)data_size, sb_data_size);
                return -EINVAL;
 
@@ -2122,17 +2119,51 @@ static int pool_preresume(struct dm_target *ti)
                r = dm_pool_resize_data_dev(pool->pmd, data_size);
                if (r) {
                        DMERR("failed to resize data device");
-                       /* FIXME Stricter than necessary: Rollback transaction instead here */
                        set_pool_mode(pool, PM_READ_ONLY);
                        return r;
                }
 
-               (void) commit_or_fallback(pool);
+               *need_commit = true;
        }
 
        return 0;
 }
 
+/*
+ * Retrieves the number of blocks of the data device from
+ * the superblock and compares it to the actual device size,
+ * thus resizing the data device in case it has grown.
+ *
+ * This both copes with opening preallocated data devices in the ctr
+ * being followed by a resume
+ * -and-
+ * calling the resume method individually after userspace has
+ * grown the data device in reaction to a table event.
+ */
+static int pool_preresume(struct dm_target *ti)
+{
+       int r;
+       bool need_commit1;
+       struct pool_c *pt = ti->private;
+       struct pool *pool = pt->pool;
+
+       /*
+        * Take control of the pool object.
+        */
+       r = bind_control_target(pool, ti);
+       if (r)
+               return r;
+
+       r = maybe_resize_data_dev(ti, &need_commit1);
+       if (r)
+               return r;
+
+       if (need_commit1)
+               (void) commit_or_fallback(pool);
+
+       return 0;
+}
+
 static void pool_resume(struct dm_target *ti)
 {
        struct pool_c *pt = ti->private;