kernel/linux.git/drivers/md/dm-thin.c, branch v4.14.286

dm: Use kzalloc for all structs with embedded biosets/mempools

2019-11-06T11:42:52+00:00

[ Upstream commit d377535405686f735b90a8ad4ba269484cd7c96e ] mempool_init()/bioset_init() require that the mempools/biosets be zeroed first; they probably should not _require_ this, but not allocating those structs with kzalloc is a fairly nonsensical thing to do (calling mempool_exit()/bioset_exit() on an uninitialized mempool/bioset is legal and safe, but only works if said memory was zeroed.) Acked-by: Mike Snitzer Signed-off-by: Kent Overstreet Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

dm thin: add sanity checks to thin-pool and external snapshot creation

2019-04-05T20:31:28+00:00

[ Upstream commit 70de2cbda8a5d788284469e755f8b097d339c240 ] Invoking dm_get_device() twice on the same device path with different modes is dangerous. Because in that case, upgrade_mode() will alloc a new 'dm_dev' and free the old one, which may be referenced by a previous caller. Dereferencing the dangling pointer will trigger kernel NULL pointer dereference. The following two cases can reproduce this issue. Actually, they are invalid setups that must be disallowed, e.g.: 1. Creating a thin-pool with read_only mode, and the same device as both metadata and data. dmsetup create thinp --table \ "0 41943040 thin-pool /dev/vdb /dev/vdb 128 0 1 read_only" BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 ... Call Trace: new_read+0xfb/0x110 [dm_bufio] dm_bm_read_lock+0x43/0x190 [dm_persistent_data] ? kmem_cache_alloc_trace+0x15c/0x1e0 __create_persistent_data_objects+0x65/0x3e0 [dm_thin_pool] dm_pool_metadata_open+0x8c/0xf0 [dm_thin_pool] pool_ctr.cold.79+0x213/0x913 [dm_thin_pool] ? realloc_argv+0x50/0x70 [dm_mod] dm_table_add_target+0x14e/0x330 [dm_mod] table_load+0x122/0x2e0 [dm_mod] ? dev_status+0x40/0x40 [dm_mod] ctl_ioctl+0x1aa/0x3e0 [dm_mod] dm_ctl_ioctl+0xa/0x10 [dm_mod] do_vfs_ioctl+0xa2/0x600 ? handle_mm_fault+0xda/0x200 ? __do_page_fault+0x26c/0x4f0 ksys_ioctl+0x60/0x90 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x55/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 2. Creating a external snapshot using the same thin-pool device. dmsetup create thinp --table \ "0 41943040 thin-pool /dev/vdc /dev/vdb 128 0 2 ignore_discard" dmsetup message /dev/mapper/thinp 0 "create_thin 0" dmsetup create snap --table \ "0 204800 thin /dev/mapper/thinp 0 /dev/mapper/thinp" BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... Call Trace: ? __alloc_pages_nodemask+0x13c/0x2e0 retrieve_status+0xa5/0x1f0 [dm_mod] ? dm_get_live_or_inactive_table.isra.7+0x20/0x20 [dm_mod] table_status+0x61/0xa0 [dm_mod] ctl_ioctl+0x1aa/0x3e0 [dm_mod] dm_ctl_ioctl+0xa/0x10 [dm_mod] do_vfs_ioctl+0xa2/0x600 ksys_ioctl+0x60/0x90 ? ksys_write+0x4f/0xb0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x55/0x150 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Jason Cai (Xiang Feng) Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin

dm thin: fix bug where bio that overwrites thin block ignores FUA

2019-02-20T09:20:54+00:00

commit 4ae280b4ee3463fa57bbe6eede26b97daff8a0f1 upstream. When provisioning a new data block for a virtual block, either because the block was previously unallocated or because we are breaking sharing, if the whole block of data is being overwritten the bio that triggered the provisioning is issued immediately, skipping copying or zeroing of the data block. When this bio completes the new mapping is inserted in to the pool's metadata by process_prepared_mapping(), where the bio completion is signaled to the upper layers. This completion is signaled without first committing the metadata. If the bio in question has the REQ_FUA flag set and the system crashes right after its completion and before the next metadata commit, then the write is lost despite the REQ_FUA flag requiring that I/O completion for this request must only be signaled after the data has been committed to non-volatile storage. Fix this by deferring the completion of overwrite bios, with the REQ_FUA flag set, until after the metadata has been committed. Cc: stable@vger.kernel.org Signed-off-by: Nikos Tsironis Acked-by: Joe Thornber Acked-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm thin: fix passdown_double_checking_shared_status()

2019-01-31T07:13:45+00:00

commit d445bd9cec1a850c2100fcf53684c13b3fd934f2 upstream. Commit 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") changed process_prepared_discard_passdown_pt1() to increment all the blocks being discarded until after the passdown had completed to avoid them being prematurely reused. IO issued to a thin device that breaks sharing with a snapshot, followed by a discard issued to snapshot(s) that previously shared the block(s), results in passdown_double_checking_shared_status() being called to iterate through the blocks double checking their reference count is zero and issuing the passdown if so. So a side effect of commit 00a0ea33b495 is passdown_double_checking_shared_status() was broken. Fix this by checking if the block reference count is greater than 1. Also, rename dm_pool_block_is_used() to dm_pool_block_is_shared(). Fixes: 00a0ea33b495 ("dm thin: do not queue freed thin mapping for next stage processing") Cc: stable@vger.kernel.org # 4.9+ Reported-by: ryan.p.norwood@gmail.com Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm thin: send event about thin-pool state change _after_ making it

2018-12-21T13:13:05+00:00

commit f6c367585d0d851349d3a9e607c43e5bea993fa1 upstream. Sending a DM event before a thin-pool state change is about to happen is a bug. It wasn't realized until it became clear that userspace response to the event raced with the actual state change that the event was meant to notify about. Fix this by first updating internal thin-pool state to reflect what the DM event is being issued about. This fixes a long-standing racey/buggy userspace device-mapper-test-suite 'resize_io' test that would get an event but not find the state it was looking for -- so it would just go on to hang because no other events caused the test to reevaluate the thin-pool's state. Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm thin metadata: try to avoid ever aborting transactions

2018-10-10T06:54:25+00:00

[ Upstream commit 3ab91828166895600efd9cdc3a0eb32001f7204a ] Committing a transaction can consume some metadata of it's own, we now reserve a small amount of metadata to cover this. Free metadata reported by the kernel will not include this reserve. If any of the reserve has been used after a commit we enter a new internal state PM_OUT_OF_METADATA_SPACE. This is reported as PM_READ_ONLY, so no userland changes are needed. If the metadata device is resized the pool will move back to PM_WRITE. These changes mean we never need to abort and rollback a transaction due to running out of metadata space. This is particularly important because there have been a handful of reports of data corruption against DM thin-provisioning that can all be attributed to the thin-pool having ran out of metadata space. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

dm thin: stop no_space_timeout worker when switching to write-mode

2018-09-09T17:55:55+00:00

commit 75294442d896f2767be34f75aca7cc2b0d01301f upstream. Now both check_for_space() and do_no_space_timeout() will read & write pool->pf.error_if_no_space. If these functions run concurrently, as shown in the following case, the default setting of "queue_if_no_space" can get lost. precondition: * error_if_no_space = false (aka "queue_if_no_space") * pool is in Out-of-Data-Space (OODS) mode * no_space_timeout worker has been queued CPU 0: CPU 1: // delete a thin device process_delete_mesg() // check_for_space() invoked by commit() set_pool_mode(pool, PM_WRITE) pool->pf.error_if_no_space = \ pt->requested_pf.error_if_no_space // timeout, pool is still in OODS mode do_no_space_timeout // "queue_if_no_space" config is lost pool->pf.error_if_no_space = true pool->pf.mode = new_mode Fix it by stopping no_space_timeout worker when switching to write mode. Fixes: bcc696fac11f ("dm thin: stay in out-of-data-space mode once no_space_timeout expires") Cc: stable@vger.kernel.org Signed-off-by: Hou Tao Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm thin: handle running out of data space vs concurrent discard

2018-07-03T09:25:05+00:00

commit a685557fbbc3122ed11e8ad3fa63a11ebc5de8c3 upstream. Discards issued to a DM thin device can complete to userspace (via fstrim) _before_ the metadata changes associated with the discards is reflected in the thinp superblock (e.g. free blocks). As such, if a user constructs a test that loops repeatedly over these steps, block allocation can fail due to discards not having completed yet: 1) fill thin device via filesystem file 2) remove file 3) fstrim From initial report, here: https://www.redhat.com/archives/dm-devel/2018-April/msg00022.html "The root cause of this issue is that dm-thin will first remove mapping and increase corresponding blocks' reference count to prevent them from being reused before DISCARD bios get processed by the underlying layers. However. increasing blocks' reference count could also increase the nr_allocated_this_transaction in struct sm_disk which makes smd->old_ll.nr_allocated + smd->nr_allocated_this_transaction bigger than smd->old_ll.nr_blocks. In this case, alloc_data_block() will never commit metadata to reset the begin pointer of struct sm_disk, because sm_disk_get_nr_free() always return an underflow value." While there is room for improvement to the space-map accounting that thinp is making use of: the reality is this test is inherently racey and will result in the previous iteration's fstrim's discard(s) completing vs concurrent block allocation, via dd, in the next iteration of the loop. No amount of space map accounting improvements will be able to allow user's to use a block before a discard of that block has completed. So the best we can really do is allow DM thinp to gracefully handle such aggressive use of all the pool's data by degrading the pool into out-of-data-space (OODS) mode. We _should_ get that behaviour already (if space map accounting didn't falsely cause alloc_data_block() to believe free space was available).. but short of that we handle the current reality that dm_pool_alloc_data_block() can return -ENOSPC. Reported-by: Dennis Yang Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

dm: fix various targets to dm_register_target after module __init resources created

2017-12-20T09:10:21+00:00

commit 7e6358d244e4706fe612a77b9c36519a33600ac0 upstream. A NULL pointer is seen if two concurrent "vgchange -ay -K " processes race to load the dm-thin-pool module: PID: 25992 TASK: ffff883cd7d23500 CPU: 4 COMMAND: "vgchange" #0 [ffff883cd743d600] machine_kexec at ffffffff81038fa9 0000001 [ffff883cd743d660] crash_kexec at ffffffff810c5992 0000002 [ffff883cd743d730] oops_end at ffffffff81515c90 0000003 [ffff883cd743d760] no_context at ffffffff81049f1b 0000004 [ffff883cd743d7b0] __bad_area_nosemaphore at ffffffff8104a1a5 0000005 [ffff883cd743d800] bad_area at ffffffff8104a2ce 0000006 [ffff883cd743d830] __do_page_fault at ffffffff8104aa6f 0000007 [ffff883cd743d950] do_page_fault at ffffffff81517bae 0000008 [ffff883cd743d980] page_fault at ffffffff81514f95 [exception RIP: kmem_cache_alloc+108] RIP: ffffffff8116ef3c RSP: ffff883cd743da38 RFLAGS: 00010046 RAX: 0000000000000004 RBX: ffffffff81121b90 RCX: ffff881bf1e78cc0 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000000 RBP: ffff883cd743da68 R8: ffff881bf1a4eb00 R9: 0000000080042000 R10: 0000000000002000 R11: 0000000000000000 R12: 00000000000000d0 R13: 0000000000000000 R14: 00000000000000d0 R15: 0000000000000246 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 0000009 [ffff883cd743da70] mempool_alloc_slab at ffffffff81121ba5 0000010 [ffff883cd743da80] mempool_create_node at ffffffff81122083 0000011 [ffff883cd743dad0] mempool_create at ffffffff811220f4 0000012 [ffff883cd743dae0] pool_ctr at ffffffffa08de049 [dm_thin_pool] 0000013 [ffff883cd743dbd0] dm_table_add_target at ffffffffa0005f2f [dm_mod] 0000014 [ffff883cd743dc30] table_load at ffffffffa0008ba9 [dm_mod] 0000015 [ffff883cd743dc90] ctl_ioctl at ffffffffa0009dc4 [dm_mod] The race results in a NULL pointer because: Process A (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target not registered; c. modprobe dm_thin_pool and wait until end. Process B (vgchange -ay -K): a. send DM_LIST_VERSIONS_CMD ioctl; b. pool_target registered; c. table_load->dm_table_add_target->pool_ctr; d. _new_mapping_cache is NULL and panic. Note: 1. process A and process B are two concurrent processes. 2. pool_target can be detected by process B but _new_mapping_cache initialization has not ended. To fix dm-thin-pool, and other targets (cache, multipath, and snapshot) with the same problem, simply dm_register_target() after all resources created during module init (as labelled with __init) are finished. Signed-off-by: monty Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

2017-09-14T20:43:16+00:00

Pull device mapper updates from Mike Snitzer: - Some request-based DM core and DM multipath fixes and cleanups - Constify a few variables in DM core and DM integrity - Add bufio optimization and checksum failure accounting to DM integrity - Fix DM integrity to avoid checking integrity of failed reads - Fix DM integrity to use init_completion - A couple DM log-writes target fixes - Simplify DAX flushing by eliminating the unnecessary flush abstraction that was stood up for DM's use. * tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dax: remove the pmem_dax_ops->flush abstraction dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK dm integrity: make blk_integrity_profile structure const dm integrity: do not check integrity for failed read operations dm log writes: fix >512b sectorsize support dm log writes: don't use all the cpu while waiting to log blocks dm ioctl: constify ioctl lookup table dm: constify argument arrays dm integrity: count and display checksum failures dm integrity: optimize writing dm-bufio buffers that are partially changed dm rq: do not update rq partially in each ending bio dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior dm mpath: complain about unsupported __multipath_map_bio() return values dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through