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| author |   Mike Snitzer <snitzer@redhat.com> | 2012-03-28 18:41:28 +0100 |
|---|---|---|
| committer |   Alasdair G Kergon <agk@redhat.com> | 2012-03-28 18:41:28 +0100 |
| commit | c4a69ecdb463a901b4645230613961e134e897cd (patch) | |
| tree | c53e0a569f3d390ea2a97f964225d5383c6401ec /drivers/md/dm-thin.c | |
| parent | dm persistent data: remove space map ref_count entries if redundant (diff) | |
| download | linux-dev-c4a69ecdb463a901b4645230613961e134e897cd.tar.xz linux-dev-c4a69ecdb463a901b4645230613961e134e897cd.zip | |
dm thin: relax hard limit on the maximum size of a metadata device
The thin metadata format can only make use of a device that is <=
THIN_METADATA_MAX_SECTORS (currently 15.9375 GB). Therefore, there is no
practical benefit to using a larger device.
However, it may be that other factors impose a certain granularity for
the space that is allocated to a device (E.g. lvm2 can impose a coarse
granularity through the use of large, >= 1 GB, physical extents).
Rather than reject a larger metadata device, during thin-pool device
construction, switch to allowing it but issue a warning if a device
larger than THIN_METADATA_MAX_SECTORS_WARNING (16 GB) is
provided. Any space over 15.9375 GB will not be used.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | drivers/md/dm-thin.c | 19 |
1 files changed, 4 insertions, 15 deletions
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) { |