mirror of https://gitee.com/openkylin/linux.git
f046f89a99
Fix a bug in dm_btree_remove that could leave leaf values with incorrect reference counts. The effect of this was that removal of a shared block could result in the space maps thinking the block was no longer used. More concretely, if you have a thin device and a snapshot of it, sending a discard to a shared region of the thin could corrupt the snapshot. Thinp uses a 2-level nested btree to store it's mappings. This first level is indexed by thin device, and the second level by logical block. Often when we're removing an entry in this mapping tree we need to rebalance nodes, which can involve shadowing them, possibly creating a copy if the block is shared. If we do create a copy then children of that node need to have their reference counts incremented. In this way reference counts percolate down the tree as shared trees diverge. The rebalance functions were incrementing the children at the appropriate time, but they were always assuming the children were internal nodes. This meant the leaf values (in our case packed block/flags entries) were not being incremented. Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| dm-array.c | ||
| dm-array.h | ||
| dm-bitset.c | ||
| dm-bitset.h | ||
| dm-block-manager.c | ||
| dm-block-manager.h | ||
| dm-btree-internal.h | ||
| dm-btree-remove.c | ||
| dm-btree-spine.c | ||
| dm-btree.c | ||
| dm-btree.h | ||
| dm-persistent-data-internal.h | ||
| dm-space-map-common.c | ||
| dm-space-map-common.h | ||
| dm-space-map-disk.c | ||
| dm-space-map-disk.h | ||
| dm-space-map-metadata.c | ||
| dm-space-map-metadata.h | ||
| dm-space-map.h | ||
| dm-transaction-manager.c | ||
| dm-transaction-manager.h | ||