[dm-devel] [PATCH for-dm-3.14-fixes 8/8] dm thin: allow metadata space larger than supported to go unused
Mike Snitzer
snitzer at redhat.com
Fri Feb 21 02:56:05 UTC 2014
It was always intended that a user could provide a thin metadata device
that is larger than the max supported by the on-disk format. The extra
space would just go unused.
That would only work when extending the metadata device, not on initial
thin-pool creation. If the user attempted to use a larger metadata
device on creation they would get an error like the following:
device-mapper: space map common: space map too large
device-mapper: transaction manager: couldn't create metadata space map
device-mapper: thin metadata: tm_create_with_sm failed
device-mapper: table: 252:17: thin-pool: Error creating metadata object
device-mapper: ioctl: error adding target to table
Fix this by allowing the initial thin-pool creation to cap the size of
the metadata area to be smaller than the size of the metadata device.
Also, the calculation for THIN_METADATA_MAX_SECTORS didn't account for
the sizeof the disk_bitmap_header. So the supported maximum metadata
size is a bit smaller (reduced from 33423360 to 33292800 sectors).
Lastly, remove the "excess space will not be used" warning message from
get_metadata_dev_size(); it resulted in printing the warning multiple
times. Factor out warn_if_metadata_device_too_big(), call it from
pool_ctr() and maybe_resize_metadata_dev().
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
---
drivers/md/dm-cache-metadata.c | 2 +-
drivers/md/dm-thin-metadata.c | 21 +++++++------
drivers/md/dm-thin-metadata.h | 5 ++--
drivers/md/dm-thin.c | 35 ++++++++++++++--------
.../md/persistent-data/dm-transaction-manager.c | 13 ++++----
.../md/persistent-data/dm-transaction-manager.h | 2 +-
6 files changed, 47 insertions(+), 31 deletions(-)
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 9ef0752..1baf615 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -323,7 +323,7 @@ static int __format_metadata(struct dm_cache_metadata *cmd)
{
int r;
- r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION,
+ r = dm_tm_create_with_sm(cmd->bm, CACHE_SUPERBLOCK_LOCATION, 0,
&cmd->tm, &cmd->metadata_sm);
if (r < 0) {
DMERR("tm_create_with_sm failed");
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 7c2bc26..3780650 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -503,11 +503,11 @@ bad_locked:
return r;
}
-static int __format_metadata(struct dm_pool_metadata *pmd)
+static int __format_metadata(struct dm_pool_metadata *pmd, dm_block_t nr_blocks)
{
int r;
- r = dm_tm_create_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION,
+ r = dm_tm_create_with_sm(pmd->bm, THIN_SUPERBLOCK_LOCATION, nr_blocks,
&pmd->tm, &pmd->metadata_sm);
if (r < 0) {
DMERR("tm_create_with_sm failed");
@@ -642,7 +642,8 @@ bad_unlock_sblock:
return r;
}
-static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device)
+static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_device,
+ dm_block_t nr_blocks)
{
int r, unformatted;
@@ -651,12 +652,13 @@ static int __open_or_format_metadata(struct dm_pool_metadata *pmd, bool format_d
return r;
if (unformatted)
- return format_device ? __format_metadata(pmd) : -EPERM;
+ return format_device ? __format_metadata(pmd, nr_blocks) : -EPERM;
return __open_metadata(pmd);
}
-static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device)
+static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool format_device,
+ dm_block_t nr_blocks)
{
int r;
@@ -668,7 +670,7 @@ static int __create_persistent_data_objects(struct dm_pool_metadata *pmd, bool f
return PTR_ERR(pmd->bm);
}
- r = __open_or_format_metadata(pmd, format_device);
+ r = __open_or_format_metadata(pmd, format_device, nr_blocks);
if (r)
dm_block_manager_destroy(pmd->bm);
@@ -808,7 +810,8 @@ out_locked:
struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
sector_t data_block_size,
- bool format_device)
+ bool format_device,
+ dm_block_t nr_blocks)
{
int r;
struct dm_pool_metadata *pmd;
@@ -828,7 +831,7 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
pmd->bdev = bdev;
pmd->data_block_size = data_block_size;
- r = __create_persistent_data_objects(pmd, format_device);
+ r = __create_persistent_data_objects(pmd, format_device, nr_blocks);
if (r) {
kfree(pmd);
return ERR_PTR(r);
@@ -1578,7 +1581,7 @@ int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
__set_abort_with_changes_flags(pmd);
__destroy_persistent_data_objects(pmd);
- r = __create_persistent_data_objects(pmd, false);
+ r = __create_persistent_data_objects(pmd, false, 0);
if (r)
pmd->fail_io = true;
diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h
index 583ff5d..e24169c 100644
--- a/drivers/md/dm-thin-metadata.h
+++ b/drivers/md/dm-thin-metadata.h
@@ -18,7 +18,7 @@
* We have one block of index, which can hold 255 index entries. Each
* index entry contains allocation info about 16k metadata blocks.
*/
-#define THIN_METADATA_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
+#define THIN_METADATA_MAX_SECTORS (255 * ((1 << 14) - 64) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
/*
* A metadata device larger than 16GB triggers a warning.
@@ -45,7 +45,8 @@ typedef uint64_t dm_thin_id;
*/
struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
sector_t data_block_size,
- bool format_device);
+ bool format_device,
+ dm_block_t nr_blocks);
int dm_pool_metadata_close(struct dm_pool_metadata *pmd);
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index cd52cf2..c4cee29 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1829,6 +1829,8 @@ static void __pool_destroy(struct pool *pool)
static struct kmem_cache *_new_mapping_cache;
+static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *);
+
static struct pool *pool_create(struct mapped_device *pool_md,
struct block_device *metadata_dev,
unsigned long block_size,
@@ -1839,8 +1841,10 @@ static struct pool *pool_create(struct mapped_device *pool_md,
struct pool *pool;
struct dm_pool_metadata *pmd;
bool format_device = read_only ? false : true;
+ dm_block_t nr_blocks = get_metadata_dev_size_in_blocks(metadata_dev);
- pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
+ pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device,
+ nr_blocks);
if (IS_ERR(pmd)) {
*error = "Error creating metadata object";
return (struct pool *)pmd;
@@ -2078,16 +2082,27 @@ static void metadata_low_callback(void *context)
dm_table_event(pool->ti->table);
}
-static sector_t get_metadata_dev_size(struct block_device *bdev)
+static sector_t get_dev_size(struct block_device *bdev)
{
- sector_t metadata_dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+ return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+}
+
+static void warn_if_metadata_device_too_big(struct block_device *bdev)
+{
+ sector_t metadata_dev_size = get_dev_size(bdev);
char buffer[BDEVNAME_SIZE];
- if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) {
+ 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;
- }
+}
+
+static sector_t get_metadata_dev_size(struct block_device *bdev)
+{
+ sector_t metadata_dev_size = get_dev_size(bdev);
+
+ if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
+ metadata_dev_size = THIN_METADATA_MAX_SECTORS;
return metadata_dev_size;
}
@@ -2174,12 +2189,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
ti->error = "Error opening metadata block device";
goto out_unlock;
}
-
- /*
- * Run for the side-effect of possibly issuing a warning if the
- * device is too big.
- */
- (void) get_metadata_dev_size(metadata_dev->bdev);
+ warn_if_metadata_device_too_big(metadata_dev->bdev);
r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
if (r) {
@@ -2378,6 +2388,7 @@ static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
return -EINVAL;;
}
+ warn_if_metadata_device_too_big(pool->md_dev);
DMINFO("%s: growing the metadata device from %llu to %llu blocks",
dm_device_name(pool->pool_md),
sb_metadata_dev_size, metadata_dev_size);
diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c
index 81da1a2..495277e 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.c
+++ b/drivers/md/persistent-data/dm-transaction-manager.c
@@ -322,7 +322,7 @@ static int dm_tm_create_internal(struct dm_block_manager *bm,
dm_block_t sb_location,
struct dm_transaction_manager **tm,
struct dm_space_map **sm,
- int create,
+ int create, dm_block_t nr_blocks,
void *sm_root, size_t sm_len)
{
int r;
@@ -338,8 +338,9 @@ static int dm_tm_create_internal(struct dm_block_manager *bm,
}
if (create) {
- r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm),
- sb_location);
+ if (!nr_blocks)
+ nr_blocks = dm_bm_nr_blocks(bm);
+ r = dm_sm_metadata_create(*sm, *tm, nr_blocks, sb_location);
if (r) {
DMERR("couldn't create metadata space map");
goto bad;
@@ -362,10 +363,10 @@ bad:
}
int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
- struct dm_transaction_manager **tm,
+ dm_block_t nr_blocks, struct dm_transaction_manager **tm,
struct dm_space_map **sm)
{
- return dm_tm_create_internal(bm, sb_location, tm, sm, 1, NULL, 0);
+ return dm_tm_create_internal(bm, sb_location, tm, sm, 1, nr_blocks, NULL, 0);
}
EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
@@ -374,7 +375,7 @@ int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
struct dm_transaction_manager **tm,
struct dm_space_map **sm)
{
- return dm_tm_create_internal(bm, sb_location, tm, sm, 0, sm_root, root_len);
+ return dm_tm_create_internal(bm, sb_location, tm, sm, 0, 0, sm_root, root_len);
}
EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
diff --git a/drivers/md/persistent-data/dm-transaction-manager.h b/drivers/md/persistent-data/dm-transaction-manager.h
index b5b1390..a8403f0 100644
--- a/drivers/md/persistent-data/dm-transaction-manager.h
+++ b/drivers/md/persistent-data/dm-transaction-manager.h
@@ -120,7 +120,7 @@ struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm);
* shouldn't be used.
*/
int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
- struct dm_transaction_manager **tm,
+ dm_block_t nr_blocks, struct dm_transaction_manager **tm,
struct dm_space_map **sm);
int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
--
1.8.3.1
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