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path: root/drivers/md/dm-snap-persistent.c (follow)
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2013-10-16dm snapshot: fix data corruptionMikulas Patocka1-6/+12
This patch fixes a particular type of data corruption that has been encountered when loading a snapshot's metadata from disk. When we allocate a new chunk in persistent_prepare, we increment ps->next_free and we make sure that it doesn't point to a metadata area by further incrementing it if necessary. When we load metadata from disk on device activation, ps->next_free is positioned after the last used data chunk. However, if this last used data chunk is followed by a metadata area, ps->next_free is positioned erroneously to the metadata area. A newly-allocated chunk is placed at the same location as the metadata area, resulting in data or metadata corruption. This patch changes the code so that ps->next_free skips the metadata area when metadata are loaded in function read_exceptions. The patch also moves a piece of code from persistent_prepare_exception to a separate function skip_metadata to avoid code duplication. CVE-2013-4299 Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Cc: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-09-20dm snapshot: workaround for a false positive lockdep warningMikulas Patocka1-1/+1
The kernel reports a lockdep warning if a snapshot is invalidated because it runs out of space. The lockdep warning was triggered by commit 0976dfc1d0cd80a4e9dfaf87bd87 ("workqueue: Catch more locking problems with flush_work()") in v3.5. The warning is false positive. The real cause for the warning is that the lockdep engine treats different instances of md->lock as a single lock. This patch is a workaround - we use flush_workqueue instead of flush_work. This code path is not performance sensitive (it is called only on initialization or invalidation), thus it doesn't matter that we flush the whole workqueue. The real fix for the problem would be to teach the lockdep engine to treat different instances of md->lock as separate locks. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.5+
2011-10-31md: Add in export.h for files using EXPORT_SYMBOLPaul Gortmaker1-0/+1
These files were getting the defines for EXPORT_SYMBOL because device.h was including module.h. But we are going to put an end to that. So add the proper export.h include now. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-08-02dm snapshot: style cleanupsJonathan Brassow1-2/+2
Coding style cleanups. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
2011-08-02dm: use vzallocJoe Perches1-2/+1
Use vzalloc() instead of vmalloc()+memset(). Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02dm: suppress endian warningsAlasdair G Kergon1-33/+38
Suppress sparse warnings about cpu_to_le32() by using __le32 types for on-disk data etc. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02dm snapshot: flush disk cache when mergingMikulas Patocka1-1/+1
This patch makes dm-snapshot flush disk cache when writing metadata for merging snapshot. Without cache flushing the disk may reorder metadata write and other data writes and there is a possibility of data corruption in case of power fault. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-05-29dm io: use fixed initial mempool sizeMikulas Patocka1-12/+1
Replace the arbitrary calculation of an initial io struct mempool size with a constant. The code calculated the number of reserved structures based on the request size and used a "magic" multiplication constant of 4. This patch changes it to reserve a fixed number - itself still chosen quite arbitrarily. Further testing might show if there is a better number to choose. Note that if there is no memory pressure, we can still allocate an arbitrary number of "struct io" structures. One structure is enough to process the whole request. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-01-13dm snapshot: persistent make metadata_wq multithreadedTejun Heo1-2/+2
metadata_wq serves on-stack work items from chunk_io(). Even if multiple chunk_io() are simultaneously in progress, each is independent and queued only once, so multithreaded workqueue can be safely used. Switch metadata_wq to multithread and flush the work item instead of the workqueue in chunk_io(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-01-13dm: convert workqueues to alloc_orderedTejun Heo1-1/+1
Convert all create[_singlethread]_work() users to the new alloc[_ordered]_workqueue(). This conversion is mechanical and doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-10-26workqueues: s/ON_STACK/ONSTACK/Andrew Morton1-1/+1
Silly though it is, completions and wait_queue_heads use foo_ONSTACK (COMPLETION_INITIALIZER_ONSTACK, DECLARE_COMPLETION_ONSTACK, __WAIT_QUEUE_HEAD_INIT_ONSTACK and DECLARE_WAIT_QUEUE_HEAD_ONSTACK) so I guess workqueues should do the same thing. s/INIT_WORK_ON_STACK/INIT_WORK_ONSTACK/ s/INIT_DELAYED_WORK_ON_STACK/INIT_DELAYED_WORK_ONSTACK/ Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-09-10dm: implement REQ_FLUSH/FUA support for bio-based dmTejun Heo1-1/+1
This patch converts bio-based dm to support REQ_FLUSH/FUA instead of now deprecated REQ_HARDBARRIER. * -EOPNOTSUPP handling logic dropped. * Preflush is handled as before but postflush is dropped and replaced with passing down REQ_FUA to member request_queues. This replaces one array wide cache flush w/ member specific FUA writes. * __split_and_process_bio() now calls __clone_and_map_flush() directly for flushes and guarantees all FLUSH bio's going to targets are zero ` length. * It's now guaranteed that all FLUSH bio's which are passed onto dm targets are zero length. bio_empty_barrier() tests are replaced with REQ_FLUSH tests. * Empty WRITE_BARRIERs are replaced with WRITE_FLUSHes. * Dropped unlikely() around REQ_FLUSH tests. Flushes are not unlikely enough to be marked with unlikely(). * Block layer now filters out REQ_FLUSH/FUA bio's if the request_queue doesn't support cache flushing. Advertise REQ_FLUSH | REQ_FUA capability. * Request based dm isn't converted yet. dm_init_request_based_queue() resets flush support to 0 for now. To avoid disturbing request based dm code, dm->flush_error is added for bio based dm while requested based dm continues to use dm->barrier_error. Lightly tested linear, stripe, raid1, snap and crypt targets. Please proceed with caution as I'm not familiar with the code base. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: dm-devel@redhat.com Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-08-12dm snapshot: persistent use define for disk header chunk sizeTomohiro Kusumi1-3/+3
This patch fixes hard-coded value for the size of a chunk that includes disk header for persistent snapshot. It should be changed to existing macro NUM_SNAPSHOT_HDR_CHUNKS instead of using hard-coded value 1. Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@jp.fujitsu.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-02-16dm snapshot: persistent annotate work_queue as on stackMike Snitzer1-1/+1
chunk_io() declares its 'struct mdata_req' on the stack and then initializes its 'struct work_struct' member. Annotate the initialization of this workqueue with INIT_WORK_ON_STACK to suppress a debugobjects warning seen when CONFIG_DEBUG_OBJECTS_WORK is enabled. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm exception store: add merge specific methodsMikulas Patocka1-2/+112
Add functions that decide how many consecutive chunks of snapshot to merge back into the origin next and to update the metadata afterwards. prepare_merge provides a pointer to the most recent still-to-be-merged chunk and returns how many previous ones are consecutive and can be processed together. commit_merge removes the nr_merged most-recent chunks permanently from the exception store. The number must not exceed that returned by prepare_merge. Introduce NUM_SNAPSHOT_HDR_CHUNKS to show where the snapshot header chunk is accounted for. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm snapshot: move cow ref from exception store to snap coreMike Snitzer1-6/+6
Store the reference to the snapshot cow device in the core snapshot code instead of each exception store. It can be accessed through the new function dm_snap_cow(). Exception stores should each now maintain a reference to their parent snapshot struct. This is cleaner and makes part of the forthcoming snapshot merge code simpler. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Reviewed-by: Jonathan Brassow <jbrassow@redhat.com> Cc: Mikulas Patocka <mpatocka@redhat.com>
2009-12-10dm snapshot: add allocated metadata to snapshot statusMike Snitzer1-6/+17
Add number of sectors used by metadata to the end of the snapshot's status line. Renamed dm_exception_store_type's 'fraction_full' to 'usage'. Renamed arguments to be clearer about what is being returned. Also added 'metadata_sectors'. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm snapshot: rename dm_snap_exception to dm_exceptionJon Brassow1-2/+2
The exception structure is not necessarily just a snapshot element (especially after we pull it out of dm-snap.c). Renaming appropriately. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10dm snapshot: avoid else clause in persistent_read_metadataJon Brassow1-25/+21
Minor code touch-up. We don't need the 'else'. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-10-16dm snapshot: use unsigned integer chunk sizeMikulas Patocka1-8/+8
Use unsigned integer chunk size. Maximum chunk size is 512kB, there won't ever be need to use 4GB chunk size, so the number can be 32-bit. This fixes compiler failure on 32-bit systems with large block devices. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-09-04dm snapshot: fix on disk chunk size validationMikulas Patocka1-8/+14
Fix some problems seen in the chunk size processing when activating a pre-existing snapshot. For a new snapshot, the chunk size can either be supplied by the creator or a default value can be used. For an existing snapshot, the chunk size in the snapshot header on disk should always be used. If someone attempts to load an existing snapshot and has the 'default chunk size' option set, the kernel uses its default value even when it is incorrect for the snapshot being loaded. This patch ensures the correct on-disk value is always used. Secondly, when the code does use the chunk size stored on the disk it is prudent to revalidate it, so the code can exit cleanly if it got corrupted as happened in https://bugzilla.redhat.com/show_bug.cgi?id=461506 . Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-09-04dm snapshot: fix header corruption race on invalidationMikulas Patocka1-10/+34
If a persistent snapshot fills up, a race can corrupt the on-disk header which causes a crash on any future attempt to activate the snapshot (typically while booting). This patch fixes the race. When the snapshot overflows, __invalidate_snapshot is called, which calls snapshot store method drop_snapshot. It goes to persistent_drop_snapshot that calls write_header. write_header constructs the new header in the "area" location. Concurrently, an existing kcopyd job may finish, call copy_callback and commit_exception method, that goes to persistent_commit_exception. persistent_commit_exception doesn't do locking, relying on the fact that callbacks are single-threaded, but it can race with snapshot invalidation and overwrite the header that is just being written while the snapshot is being invalidated. The result of this race is a corrupted header being written that can lead to a crash on further reactivation (if chunk_size is zero in the corrupted header). The fix is to use separate memory areas for each. See the bug: https://bugzilla.redhat.com/show_bug.cgi?id=461506 Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-09-04dm snapshot: refactor zero_disk_area to use chunk_ioMikulas Patocka1-19/+7
Refactor chunk_io to prepare for the fix in the following patch. Pass an area pointer to chunk_io and simplify zero_disk_area to use chunk_io. No functional change. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22dm snapshot: use barrier when writing exception storeMikulas Patocka1-1/+1
Send barrier requests when updating the exception area. Exception area updates need to be ordered w.r.t. data writes, so that the writes are not reordered in hardware disk cache. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-05-22block: Do away with the notion of hardsect_sizeMartin K. Petersen1-1/+1
Until now we have had a 1:1 mapping between storage device physical block size and the logical block sized used when addressing the device. With SATA 4KB drives coming out that will no longer be the case. The sector size will be 4KB but the logical block size will remain 512-bytes. Hence we need to distinguish between the physical block size and the logical ditto. This patch renames hardsect_size to logical_block_size. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-02dm snapshot: persistent fix dtr cleanupJonathan Brassow1-5/+15
The persistent exception store destructor does not properly account for all conditions in which it can be called. If it is called after 'ctr' but before 'read_metadata' (e.g. if something else in 'snapshot_ctr' fails) then it will attempt to free areas of memory that haven't been allocated yet. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02dm snapshot: move status to exception storeJonathan Brassow1-4/+12
Let the exception store types print out their status through the new API, rather than having the snapshot code do it. Adjust the buffer position to allow for the preceding DMEMIT in the arguments to type->status(). Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02dm snapshot: remove dm_snap header useJonathan Brassow1-29/+27
Move useful functions out of dm-snap.h and stop using dm-snap.h. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02dm exception store: move cow pointerJonathan Brassow1-5/+5
Move COW device from snapshot to exception store. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02dm exception store: move chunk_fieldsJonathan Brassow1-23/+24
Move chunk fields from snapshot to exception store. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02dm exception store: introduce registryJonathan Brassow1-10/+57
Move exception stores into a registry. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02dm exception store: separate type from instanceJonathan Brassow1-6/+7
Introduce struct dm_exception_store_type. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06dm snapshot: extend exception store functionsJonathan Brassow1-16/+26
Supply dm_add_exception as a callback to the read_metadata function. Add a status function ready for a later patch and name the functions consistently. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06dm snapshot: split out exception store implementationsAlasdair G Kergon1-0/+694
Move the existing snapshot exception store implementations out into separate files. Later patches will place these behind a new interface in preparation for alternative implementations. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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