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| author | Joe Thornber <ejt@redhat.com> | 2012-03-28 18:41:27 +0100 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2012-03-28 18:41:27 +0100 |
| commit | 71fd5ae25d88841c08d5bbea90c0f0a12ca05509 (patch) | |
| tree | 763ec9657bd25e4d42f1f6774faa65166364eede /Documentation/device-mapper | |
| parent | 905e51b39a5558706a6ed883fe104de3d417050b (diff) | |
| download | lwn-71fd5ae25d88841c08d5bbea90c0f0a12ca05509.tar.gz lwn-71fd5ae25d88841c08d5bbea90c0f0a12ca05509.zip | |
dm persistent data: remove space map ref_count entries if redundant
Save space by removing entries from the space map ref_count tree if
they're no longer needed.
Ref counts are stored in two places: a bitmap if the ref_count is
below 3, or a btree of uint32_t if 3 or above.
When a ref_count that was above 3 drops below we can remove it from
the tree and save some metadata space. This removal was commented out
before because I was unsure why this was causing under-populated btree
nodes. Earlier patches have fixed this issue.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'Documentation/device-mapper')
0 files changed, 0 insertions, 0 deletions