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-rw-r--r--drivers/md/dm-thin-metadata.c136
-rw-r--r--drivers/md/dm-thin-metadata.h13
-rw-r--r--drivers/md/dm-thin.c42
-rw-r--r--drivers/md/persistent-data/dm-transaction-manager.c2
4 files changed, 182 insertions, 11 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;
diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h
index ed4725e67c96..b88918ccdaf6 100644
--- a/drivers/md/dm-thin-metadata.h
+++ b/drivers/md/dm-thin-metadata.h
@@ -90,11 +90,18 @@ int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
/*
* Hold/get root for userspace transaction.
+ *
+ * The metadata snapshot is a copy of the current superblock (minus the
+ * space maps). Userland can access the data structures for READ
+ * operations only. A small performance hit is incurred by providing this
+ * copy of the metadata to userland due to extra copy-on-write operations
+ * on the metadata nodes. Release this as soon as you finish with it.
*/
-int dm_pool_hold_metadata_root(struct dm_pool_metadata *pmd);
+int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd);
+int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd);
-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);
/*
* Actions on a single virtual device.
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index db1b041ce975..37fdaf81bd1f 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2284,6 +2284,36 @@ static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct po
return 0;
}
+static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ int r;
+
+ r = check_arg_count(argc, 1);
+ if (r)
+ return r;
+
+ r = dm_pool_reserve_metadata_snap(pool->pmd);
+ if (r)
+ DMWARN("reserve_metadata_snap message failed.");
+
+ return r;
+}
+
+static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ int r;
+
+ r = check_arg_count(argc, 1);
+ if (r)
+ return r;
+
+ r = dm_pool_release_metadata_snap(pool->pmd);
+ if (r)
+ DMWARN("release_metadata_snap message failed.");
+
+ return r;
+}
+
/*
* Messages supported:
* create_thin <dev_id>
@@ -2291,6 +2321,8 @@ static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct po
* delete <dev_id>
* trim <dev_id> <new_size_in_sectors>
* set_transaction_id <current_trans_id> <new_trans_id>
+ * reserve_metadata_snap
+ * release_metadata_snap
*/
static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
{
@@ -2310,6 +2342,12 @@ static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
else if (!strcasecmp(argv[0], "set_transaction_id"))
r = process_set_transaction_id_mesg(argc, argv, pool);
+ else if (!strcasecmp(argv[0], "reserve_metadata_snap"))
+ r = process_reserve_metadata_snap_mesg(argc, argv, pool);
+
+ else if (!strcasecmp(argv[0], "release_metadata_snap"))
+ r = process_release_metadata_snap_mesg(argc, argv, pool);
+
else
DMWARN("Unrecognised thin pool target message received: %s", argv[0]);
@@ -2369,7 +2407,7 @@ static int pool_status(struct dm_target *ti, status_type_t type,
if (r)
return r;
- r = dm_pool_get_held_metadata_root(pool->pmd, &held_root);
+ r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
if (r)
return r;
@@ -2465,7 +2503,7 @@ static struct target_type pool_target = {
.name = "thin-pool",
.features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
DM_TARGET_IMMUTABLE,
- .version = {1, 1, 0},
+ .version = {1, 2, 0},
.module = THIS_MODULE,
.ctr = pool_ctr,
.dtr = pool_dtr,
diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c
index 6f8d38747d7f..400fe144c0cd 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.c
+++ b/drivers/md/persistent-data/dm-transaction-manager.c
@@ -249,6 +249,7 @@ int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
return r;
}
+EXPORT_SYMBOL_GPL(dm_tm_shadow_block);
int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
struct dm_block_validator *v,
@@ -259,6 +260,7 @@ int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
return dm_bm_read_lock(tm->bm, b, v, blk);
}
+EXPORT_SYMBOL_GPL(dm_tm_read_lock);
int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b)
{
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 02:04:32 +0100