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authorMike Snitzer <snitzer@redhat.com>2014-02-13 08:58:15 +0400
committerMike Snitzer <snitzer@redhat.com>2014-02-27 20:49:08 +0400
commit7d48935eff401bb7970e73e822871a10e3643df1 (patch)
treecc7523512553a162b66e37d022da2c2e8acfee22 /drivers/md/persistent-data/dm-space-map-metadata.h
parenta1989b330093578ea5470bea0a00f940c444c466 (diff)
downloadlinux-7d48935eff401bb7970e73e822871a10e3643df1.tar.xz
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 <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
Diffstat (limited to 'drivers/md/persistent-data/dm-space-map-metadata.h')
-rw-r--r--drivers/md/persistent-data/dm-space-map-metadata.h11
1 files changed, 11 insertions, 0 deletions
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.