diff options
| -rw-r--r-- | Documentation/device-mapper/thin-provisioning.txt | 8 | ||||
| -rw-r--r-- | drivers/md/dm-thin-metadata.c | 3 | ||||
| -rw-r--r-- | drivers/md/dm-thin-metadata.h | 13 | ||||
| -rw-r--r-- | drivers/md/dm-thin.c | 19 |
4 files changed, 25 insertions, 18 deletions
diff --git a/Documentation/device-mapper/thin-provisioning.txt b/Documentation/device-mapper/thin-provisioning.txt index da50347c0053..a119fbdd0604 100644 --- a/Documentation/device-mapper/thin-provisioning.txt +++ b/Documentation/device-mapper/thin-provisioning.txt @@ -75,10 +75,12 @@ less sharing than average you'll need a larger-than-average metadata device. As a guide, we suggest you calculate the number of bytes to use in the metadata device as 48 * $data_dev_size / $data_block_size but round it up -to 2MB if the answer is smaller. The largest size supported is 16GB. +to 2MB if the answer is smaller. If you're creating large numbers of +snapshots which are recording large amounts of change, you may find you +need to increase this. -If you're creating large numbers of snapshots which are recording large -amounts of change, you may need find you need to increase this. +The largest size supported is 16GB: If the device is larger, +a warning will be issued and the excess space will not be used. Reloading a pool table ---------------------- diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index a680c761341f..737d38865b69 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -713,6 +713,9 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev, if (r) goto bad; + if (bdev_size > THIN_METADATA_MAX_SECTORS) + bdev_size = THIN_METADATA_MAX_SECTORS; + disk_super = dm_block_data(sblock); disk_super->magic = cpu_to_le64(THIN_SUPERBLOCK_MAGIC); disk_super->version = cpu_to_le32(THIN_VERSION); diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h index 859c16896877..ed4725e67c96 100644 --- a/drivers/md/dm-thin-metadata.h +++ b/drivers/md/dm-thin-metadata.h @@ -11,6 +11,19 @@ #define THIN_METADATA_BLOCK_SIZE 4096 +/* + * The metadata device is currently limited in size. + * + * 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))) + +/* + * A metadata device larger than 16GB triggers a warning. + */ +#define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT)) + /*----------------------------------------------------------------*/ struct dm_pool_metadata; diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index bcb143396fe0..2378ee88b1e8 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -33,16 +33,6 @@ #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) /* - * The metadata device is currently limited in size. The limitation is - * checked lower down in dm-space-map-metadata, but we also check it here - * so we can fail early. - * - * We have one block of index, which can hold 255 index entries. Each - * index entry contains allocation info about 16k metadata blocks. - */ -#define METADATA_DEV_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT))) - -/* * Device id is restricted to 24 bits. */ #define MAX_DEV_ID ((1 << 24) - 1) @@ -1736,6 +1726,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) 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. @@ -1757,11 +1748,9 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) } metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT; - if (metadata_dev_size > METADATA_DEV_MAX_SECTORS) { - ti->error = "Metadata device is too large"; - r = -EINVAL; - goto out_metadata; - } + 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); r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); if (r) { |