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path: root/drivers/md/dm-thin-metadata.c
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Diffstat (limited to 'drivers/md/dm-thin-metadata.c')
-rw-r--r--drivers/md/dm-thin-metadata.c136
1 files changed, 130 insertions, 6 deletions
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 737d38865b69..3e2907f0bc46 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -1082,12 +1082,89 @@ int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
return 0;
}
-static int __get_held_metadata_root(struct dm_pool_metadata *pmd,
- dm_block_t *result)
+static int __reserve_metadata_snap(struct dm_pool_metadata *pmd)
+{
+ int r, inc;
+ struct thin_disk_superblock *disk_super;
+ struct dm_block *copy, *sblock;
+ dm_block_t held_root;
+
+ /*
+ * Copy the superblock.
+ */
+ dm_sm_inc_block(pmd->metadata_sm, THIN_SUPERBLOCK_LOCATION);
+ r = dm_tm_shadow_block(pmd->tm, THIN_SUPERBLOCK_LOCATION,
+ &sb_validator, &copy, &inc);
+ if (r)
+ return r;
+
+ BUG_ON(!inc);
+
+ held_root = dm_block_location(copy);
+ disk_super = dm_block_data(copy);
+
+ if (le64_to_cpu(disk_super->held_root)) {
+ DMWARN("Pool metadata snapshot already exists: release this before taking another.");
+
+ dm_tm_dec(pmd->tm, held_root);
+ dm_tm_unlock(pmd->tm, copy);
+ pmd->need_commit = 1;
+
+ return -EBUSY;
+ }
+
+ /*
+ * Wipe the spacemap since we're not publishing this.
+ */
+ memset(&disk_super->data_space_map_root, 0,
+ sizeof(disk_super->data_space_map_root));
+ memset(&disk_super->metadata_space_map_root, 0,
+ sizeof(disk_super->metadata_space_map_root));
+
+ /*
+ * Increment the data structures that need to be preserved.
+ */
+ dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->data_mapping_root));
+ dm_tm_inc(pmd->tm, le64_to_cpu(disk_super->device_details_root));
+ dm_tm_unlock(pmd->tm, copy);
+
+ /*
+ * Write the held root into the superblock.
+ */
+ r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
+ &sb_validator, &sblock);
+ if (r) {
+ dm_tm_dec(pmd->tm, held_root);
+ pmd->need_commit = 1;
+ return r;
+ }
+
+ disk_super = dm_block_data(sblock);
+ disk_super->held_root = cpu_to_le64(held_root);
+ dm_bm_unlock(sblock);
+
+ pmd->need_commit = 1;
+
+ return 0;
+}
+
+int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd)
+{
+ int r;
+
+ down_write(&pmd->root_lock);
+ r = __reserve_metadata_snap(pmd);
+ up_write(&pmd->root_lock);
+
+ return r;
+}
+
+static int __release_metadata_snap(struct dm_pool_metadata *pmd)
{
int r;
struct thin_disk_superblock *disk_super;
- struct dm_block *sblock;
+ struct dm_block *sblock, *copy;
+ dm_block_t held_root;
r = dm_bm_write_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
&sb_validator, &sblock);
@@ -1095,18 +1172,65 @@ static int __get_held_metadata_root(struct dm_pool_metadata *pmd,
return r;
disk_super = dm_block_data(sblock);
+ held_root = le64_to_cpu(disk_super->held_root);
+ disk_super->held_root = cpu_to_le64(0);
+ pmd->need_commit = 1;
+
+ dm_bm_unlock(sblock);
+
+ if (!held_root) {
+ DMWARN("No pool metadata snapshot found: nothing to release.");
+ return -EINVAL;
+ }
+
+ r = dm_tm_read_lock(pmd->tm, held_root, &sb_validator, &copy);
+ if (r)
+ return r;
+
+ disk_super = dm_block_data(copy);
+ dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->data_mapping_root));
+ dm_sm_dec_block(pmd->metadata_sm, le64_to_cpu(disk_super->device_details_root));
+ dm_sm_dec_block(pmd->metadata_sm, held_root);
+
+ return dm_tm_unlock(pmd->tm, copy);
+}
+
+int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd)
+{
+ int r;
+
+ down_write(&pmd->root_lock);
+ r = __release_metadata_snap(pmd);
+ up_write(&pmd->root_lock);
+
+ return r;
+}
+
+static int __get_metadata_snap(struct dm_pool_metadata *pmd,
+ dm_block_t *result)
+{
+ int r;
+ struct thin_disk_superblock *disk_super;
+ struct dm_block *sblock;
+
+ r = dm_bm_read_lock(pmd->bm, THIN_SUPERBLOCK_LOCATION,
+ &sb_validator, &sblock);
+ if (r)
+ return r;
+
+ disk_super = dm_block_data(sblock);
*result = le64_to_cpu(disk_super->held_root);
return dm_bm_unlock(sblock);
}
-int dm_pool_get_held_metadata_root(struct dm_pool_metadata *pmd,
- dm_block_t *result)
+int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
+ dm_block_t *result)
{
int r;
down_read(&pmd->root_lock);
- r = __get_held_metadata_root(pmd, result);
+ r = __get_metadata_snap(pmd, result);
up_read(&pmd->root_lock);
return r;