user/sven/linux.git/drivers/md/persistent-data, branch v5.15.16

dm btree remove: fix use after free in rebalance_children()

2021-12-22T08:32:36Z

commit 1b8d2789dad0005fd5e7d35dab26a8e1203fb6da upstream. Move dm_tm_unlock() after dm_tm_dec(). Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm btree remove: assign new_root only when removal succeeds

2021-06-25T19:25:24Z

remove_raw() in dm_btree_remove() may fail due to IO read error (e.g. read the content of origin block fails during shadowing), and the value of shadow_spine::root is uninitialized, but the uninitialized value is still assign to new_root in the end of dm_btree_remove(). For dm-thin, the value of pmd->details_root or pmd->root will become an uninitialized value, so if trying to read details_info tree again out-of-bound memory may occur as showed below: general protection fault, probably for non-canonical address 0x3fdcb14c8d7520 CPU: 4 PID: 515 Comm: dmsetup Not tainted 5.13.0-rc6 Hardware name: QEMU Standard PC RIP: 0010:metadata_ll_load_ie+0x14/0x30 Call Trace: sm_metadata_count_is_more_than_one+0xb9/0xe0 dm_tm_shadow_block+0x52/0x1c0 shadow_step+0x59/0xf0 remove_raw+0xb2/0x170 dm_btree_remove+0xf4/0x1c0 dm_pool_delete_thin_device+0xc3/0x140 pool_message+0x218/0x2b0 target_message+0x251/0x290 ctl_ioctl+0x1c4/0x4d0 dm_ctl_ioctl+0xe/0x20 __x64_sys_ioctl+0x7b/0xb0 do_syscall_64+0x40/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixing it by only assign new_root when removal succeeds Signed-off-by: Hou Tao Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer

dm space map disk: cache a small number of index entries

2021-06-04T16:07:23Z

The disk space map stores it's index entries in a btree, these are accessed very frequently, so having a few cached makes a big difference to performance. With this change provisioning a new block takes roughly 20% less cpu. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm space maps: improve performance with inc/dec on ranges of blocks

2021-06-04T16:07:22Z

When we break sharing on btree nodes we typically need to increment the reference counts to every value held in the node. This can cause a lot of repeated calls to the space maps. Fix this by changing the interface to the space map inc/dec methods to take ranges of adjacent blocks to be operated on. For installations that are using a lot of snapshots this will reduce cpu overhead of fundamental operations such as provisioning a new block, or deleting a snapshot, by as much as 10 times. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm space maps: don't reset space map allocation cursor when committing

2021-06-04T16:07:21Z

Current commit code resets the place where the search for free blocks will begin back to the start of the metadata device. There are a couple of repercussions to this: - The first allocation after the commit is likely to take longer than normal as it searches for a free block in an area that is likely to have very few free blocks (if any). - Any free blocks it finds will have been recently freed. Reusing them means we have fewer old copies of the metadata to aid recovery from hardware error. Fix these issues by leaving the cursor alone, only resetting when the search hits the end of the metadata device. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm btree: improve btree residency

2021-06-04T16:07:20Z

This commit improves the residency of btrees built in the metadata for dm-thin and dm-cache. When inserting a new entry into a full btree node the current code splits the node into two. This can result in very many half full nodes, particularly if the insertions are occurring in an ascending order (as happens in dm-thin with large writes). With this commit, when we insert into a full node we first try and move some entries to a neighbouring node that has space, failing that it tries to split two neighbouring nodes into three. Results are given below. 'Residency' is how full nodes are on average as a percentage. Average instruction counts for the operations are given to show the extra processing has little overhead. +--------------------------+--------------------------+ | Before | After | +------------+-----------+-----------+--------------+-----------+--------------+ | Test | Phase | Residency | Instructions | Residency | Instructions | +------------+-----------+-----------+--------------+-----------+--------------+ | Ascending | insert | 50 | 1876 | 96 | 1930 | | | overwrite | 50 | 1789 | 96 | 1746 | | | lookup | 50 | 778 | 96 | 778 | | Descending | insert | 50 | 3024 | 96 | 3181 | | | overwrite | 50 | 1789 | 96 | 1746 | | | lookup | 50 | 778 | 96 | 778 | | Random | insert | 68 | 3800 | 84 | 3736 | | | overwrite | 68 | 4254 | 84 | 3911 | | | lookup | 68 | 779 | 84 | 779 | | Runs | insert | 63 | 2546 | 82 | 2815 | | | overwrite | 63 | 2013 | 82 | 1986 | | | lookup | 63 | 778 | 82 | 779 | +------------+-----------+-----------+--------------+-----------+--------------+ Ascending - keys are inserted in ascending order. Descending - keys are inserted in descending order. Random - keys are inserted in random order. Runs - keys are split into ascending runs of ~20 length. Then the runs are shuffled. Signed-off-by: Joe Thornber Signed-off-by: Colin Ian King # contains_key() fix Signed-off-by: Mike Snitzer

dm space map common: fix division bug in sm_ll_find_free_block()

2021-04-19T16:48:13Z

This division bug meant the search for free metadata space could skip the final allocation bitmap's worth of entries. Fix affects DM thinp, cache and era targets. Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Tested-by: Ming-Hung Tsai Signed-off-by: Mike Snitzer

dm persistent data: packed struct should have an aligned() attribute too

2021-04-19T16:48:12Z

Otherwise most non-x86 architectures (e.g. riscv, arm) will resort to byte-by-byte access. Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm btree spine: remove paranoid node_check call in node_prep_for_write()

2021-04-19T16:47:57Z

Remove this extra BUG_ON() that calls node_check() -- which avoids extra crc checking. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm space map disk: remove redundant calls to sm_disk_get_nr_free()

2021-04-19T16:36:46Z

Both sm_disk_new_block and sm_disk_commit are needlessly calling sm_disk_get_nr_free(). Looks like old queries used for some debugging. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer