On Wed, Jul 24 2013 at 8:50pm -0400, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > Do not allow a cache device to use a metadata device that is already > in use by another cache device. > > Add list member to the cache structure. Also reorder members in the > cache structure to eliminate 6 out of 7 holes (reclaiming 24 bytes). > > Example: > echo "0 8192 linear 253:1 0" | dmsetup create metadata > echo "0 2097152 linear 253:1 8192" | dmsetup create ssd > echo "0 33554432 linear 253:0 0" | dmsetup create origin > echo "0 33554432 cache /dev/mapper/metadata /dev/mapper/ssd /dev/mapper/origin 512 0 default 0" | dmsetup create cache1 > echo "0 33554432 cache /dev/mapper/metadata /dev/mapper/ssd /dev/mapper/origin 512 0 default 0" | dmsetup create cache2 > device-mapper: reload ioctl on cache2 failed: Device or resource busy > Command failed > > Kernel log shows: > device-mapper: table: 253:8: cache: metadata device already in use by a cache > device-mapper: ioctl: error adding target to table Self-NACK. This patch doesn't handle reloading a cache device. The cache struct member reshuffle may be useful to better align on cachelines and eliminate holes but I'll repost a separate patch accordingly. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
