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path: root/drivers/md/persistent-data
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* dm persistent data: remove space map ref_count entries if redundantJoe Thornber2012-03-28
| | | | | | | | | | | | | | | | | 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>
* dm persistent data: remove redundant value_size arg from value_ptrJoe Thornber2012-03-28
| | | | | | | | | | | | | Now that the value_size is held within every node of the btrees we can remove this argument from value_ptr(). For the last few months a BUG_ON has been checking this argument is the same as that held in the node. No issues were reported. So this is a safe change. 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>
* dm persistent data: fix btree rebalancing after removeJoe Thornber2012-03-28
| | | | | | | | | | | | | | | | | | When we remove an entry from a node we sometimes rebalance with it's two neighbours. This wasn't being done correctly; in some cases entries have to move all the way from the right neighbour to the left neighbour, or vice versa. This patch pretty much re-writes the balancing code to fix it. This code is barely used currently; only when you delete a thin device, and then only if you have hundreds of them in the same pool. Once we have discard support, which removes mappings, this will be used much more heavily. Signed-off-by: Joe Thornber <ejt@redhat.com> Cc: stable@kernel.org Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* device-mapper: using EXPORT_SYBOL in dm-space-map-checker.c needs export.hStephen Rothwell2011-11-07
| | | | | | | Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* drivers/md: change module.h -> export.h in persistent-data/dm-*Paul Gortmaker2011-11-07
| | | | | | | | | | For the files which are not themselves modular, we can change them to include only the smaller export.h since all they are doing is looking for EXPORT_SYMBOL. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dm: add persistent data libraryJoe Thornber2011-10-31
The persistent-data library offers a re-usable framework for the storage and management of on-disk metadata in device-mapper targets. It's used by the thin-provisioning target in the next patch and in an upcoming hierarchical storage target. For further information, please read Documentation/device-mapper/persistent-data.txt Signed-off-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>