From 7d48935eff401bb7970e73e822871a10e3643df1 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Wed, 12 Feb 2014 23:58:15 -0500 Subject: dm thin: allow metadata space larger than supported to go unused 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. Unfortunately that never worked. 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 metadata space map creation to cap its size at the max number of blocks supported (DM_SM_METADATA_MAX_BLOCKS). get_metadata_dev_size() must also impose DM_SM_METADATA_MAX_BLOCKS (via THIN_METADATA_MAX_SECTORS), otherwise extending metadata would cap at THIN_METADATA_MAX_SECTORS_WARNING (which is larger than supported). 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 Acked-by: Joe Thornber --- drivers/md/persistent-data/dm-space-map-metadata.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'drivers/md/persistent-data/dm-space-map-metadata.h') diff --git a/drivers/md/persistent-data/dm-space-map-metadata.h b/drivers/md/persistent-data/dm-space-map-metadata.h index 39bba0801cf2..64df923974d8 100644 --- a/drivers/md/persistent-data/dm-space-map-metadata.h +++ b/drivers/md/persistent-data/dm-space-map-metadata.h @@ -9,6 +9,17 @@ #include "dm-transaction-manager.h" +#define DM_SM_METADATA_BLOCK_SIZE (4096 >> SECTOR_SHIFT) + +/* + * 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 DM_SM_METADATA_MAX_BLOCKS (255 * ((1 << 14) - 64)) +#define DM_SM_METADATA_MAX_SECTORS (DM_SM_METADATA_MAX_BLOCKS * DM_SM_METADATA_BLOCK_SIZE) + /* * Unfortunately we have to use two-phase construction due to the cycle * between the tm and sm. -- cgit v1.2.3