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/dm-thin.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) (limited to 'drivers/md/dm-thin.c') diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 4cf4b198cb60..7e84baccf0ad 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -2000,16 +2000,27 @@ 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) +{ + 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 = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; + 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; } @@ -2018,7 +2029,7 @@ static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev) { sector_t metadata_dev_size = get_metadata_dev_size(bdev); - sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT); + sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE); return metadata_dev_size; } @@ -2096,12 +2107,7 @@ 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) { @@ -2288,6 +2294,7 @@ static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit) return -EINVAL; } else if (metadata_dev_size > sb_metadata_dev_size) { + 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); -- cgit v1.2.2