dm cache: share cache-metadata object across inactive and active DM tables

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If a DM table is reloaded with an inactive table when the device is not
suspended (normal procedure for LVM2), then there will be two dm-bufio
objects that can diverge.  This can lead to a situation where the
inactive table uses bufio to read metadata at the same time the active
table writes metadata -- resulting in the inactive table having stale
metadata buffers once it is promoted to the active table slot.

Fix this by using reference counting and a global list of cache metadata
objects to ensure there is only one metadata object per metadata device.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org

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Joe Thornber 2015-01-23 10:00:07 +00:00 • committed by Mike Snitzer

parent 5164bece16

commit 9b1cc9f251

1 changed files with 95 additions and 6 deletions

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drivers/md/dm-cache-metadata.c

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