kernel/drivers/md/persistent-data/dm-btree-remove.c, branch linux-6.9.y

dm: add missing empty lines

2023-02-14T19:23:06Z

Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm: change "unsigned" to "unsigned int"

2023-02-14T19:23:06Z

Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm: add missing SPDX-License-Indentifiers

2023-02-14T19:23:06Z

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has deprecated its use. Suggested-by: John Wiele Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm btree remove: change a bunch of BUG_ON() calls to proper errors

2022-01-04T18:48:12Z

Abuse of BUG_ON() is never appropriate, best to propagate errors to fail gracefully (rather than take the entire system down). Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

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

2021-11-24T17:07:39Z

Move dm_tm_unlock() after dm_tm_dec(). Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

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 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 btree: increase rebalance threshold in __rebalance2()

2019-12-05T20:27:52Z

We got the following warnings from thin_check during thin-pool setup: $ thin_check /dev/vdb examining superblock examining devices tree missing devices: [1, 84] too few entries in btree_node: 41, expected at least 42 (block 138, max_entries = 126) examining mapping tree The phenomenon is the number of entries in one node of details_info tree is less than (max_entries / 3). And it can be easily reproduced by the following procedures: $ new a thin pool $ presume the max entries of details_info tree is 126 $ new 127 thin devices (e.g. 1~127) to make the root node being full and then split $ remove the first 43 (e.g. 1~43) thin devices to make the children reblance repeatedly $ stop the thin pool $ thin_check The root cause is that the B-tree removal procedure in __rebalance2() doesn't guarantee the invariance: the minimal number of entries in non-root node should be >= (max_entries / 3). Simply fix the problem by increasing the rebalance threshold to make sure the number of entries in each child will be greater than or equal to (max_entries / 3 + 1), so no matter which child is used for removal, the number will still be valid. Cc: stable@vger.kernel.org Signed-off-by: Hou Tao Acked-by: Joe Thornber Signed-off-by: Mike Snitzer

Merge tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2015-11-05T05:19:53Z

Pull device mapper updates from Mike Snitzer: "Smaller set of DM changes for this merge. I've based these changes on Jens' for-4.4/reservations branch because the associated DM changes required it. - Revert a dm-multipath change that caused a regression for unprivledged users (e.g. kvm guests) that issued ioctls when a multipath device had no available paths. - Include Christoph's refactoring of DM's ioctl handling and add support for passing through persistent reservations with DM multipath. - All other changes are very simple cleanups" * tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm switch: simplify conditional in alloc_region_table() dm delay: document that offsets are specified in sectors dm delay: capitalize the start of an delay_ctr() error message dm delay: Use DM_MAPIO macros instead of open-coded equivalents dm linear: remove redundant target name from error messages dm persistent data: eliminate unnecessary return values dm: eliminate unused "bioset" process for each bio-based DM device dm: convert ffs to __ffs dm: drop NULL test before kmem_cache_destroy() and mempool_destroy() dm: add support for passing through persistent reservations dm: refactor ioctl handling Revert "dm mpath: fix stalls when handling invalid ioctls" dm: initialize non-blk-mq queue data before queue is used

dm persistent data: eliminate unnecessary return values

2015-10-31T23:06:02Z

dm_bm_unlock and dm_tm_unlock return an integer value but the returned value is always 0. The calling code sometimes checks the return value and sometimes doesn't. Eliminate these unnecessary return values and also the checks for them. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer