Commit Graph

61 Commits

Author SHA1 Message Date
Linus Torvalds 20cf903a0c - Add flags argument to dm_bufio_client_create and introduce
DM_BUFIO_CLIENT_NO_SLEEP flag to have dm-bufio use spinlock rather
   than mutex for its locking.
 
 - Add optional "try_verify_in_tasklet" feature to DM verity target.
   This feature gives users the option to improve IO latency by using a
   tasklet to verify, using hashes in bufio's cache, rather than wait
   to schedule a work item via workqueue. But if there is a bufio cache
   miss, or an error, then the tasklet will fallback to using workqueue.
 
 - Incremental changes to both dm-bufio and the DM verity target to use
   jump_label to minimize cost of branching associated with the niche
   "try_verify_in_tasklet" feature. DM-bufio in particular is used by
   quite a few other DM targets so it doesn't make sense to incur
   additional bufio cost in those targets purely for the benefit of
   this niche verity feature if the feature isn't ever used.
 
 - Optimize verity_verify_io, which is used by both workqueue and
   tasklet based verification, if FEC is not configured or tasklet
   based verification isn't used.
 
 - Remove DM verity target's verify_wq's use of the WQ_CPU_INTENSIVE
   flag since it uses WQ_UNBOUND. Also, use the WQ_HIGHPRI flag if
   "try_verify_in_tasklet" is specified.
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Merge tag 'for-6.0/dm-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull more device mapper updates from Mike Snitzer:

 - Add flags argument to dm_bufio_client_create and introduce
   DM_BUFIO_CLIENT_NO_SLEEP flag to have dm-bufio use spinlock rather
   than mutex for its locking.

 - Add optional "try_verify_in_tasklet" feature to DM verity target.
   This feature gives users the option to improve IO latency by using a
   tasklet to verify, using hashes in bufio's cache, rather than wait to
   schedule a work item via workqueue. But if there is a bufio cache
   miss, or an error, then the tasklet will fallback to using workqueue.

 - Incremental changes to both dm-bufio and the DM verity target to use
   jump_label to minimize cost of branching associated with the niche
   "try_verify_in_tasklet" feature. DM-bufio in particular is used by
   quite a few other DM targets so it doesn't make sense to incur
   additional bufio cost in those targets purely for the benefit of this
   niche verity feature if the feature isn't ever used.

 - Optimize verity_verify_io, which is used by both workqueue and
   tasklet based verification, if FEC is not configured or tasklet based
   verification isn't used.

 - Remove DM verity target's verify_wq's use of the WQ_CPU_INTENSIVE
   flag since it uses WQ_UNBOUND. Also, use the WQ_HIGHPRI flag if
   "try_verify_in_tasklet" is specified.

* tag 'for-6.0/dm-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm verity: have verify_wq use WQ_HIGHPRI if "try_verify_in_tasklet"
  dm verity: remove WQ_CPU_INTENSIVE flag since using WQ_UNBOUND
  dm verity: only copy bvec_iter in verity_verify_io if in_tasklet
  dm verity: optimize verity_verify_io if FEC not configured
  dm verity: conditionally enable branching for "try_verify_in_tasklet"
  dm bufio: conditionally enable branching for DM_BUFIO_CLIENT_NO_SLEEP
  dm verity: allow optional args to alter primary args handling
  dm verity: Add optional "try_verify_in_tasklet" feature
  dm bufio: Add DM_BUFIO_CLIENT_NO_SLEEP flag
  dm bufio: Add flags argument to dm_bufio_client_create
2022-08-06 11:09:55 -07:00
Nathan Huckleberry 0fcb100d50 dm bufio: Add flags argument to dm_bufio_client_create
Add a flags argument to dm_bufio_client_create and update all the
callers. This is in preparation to add the DM_BUFIO_NO_SLEEP flag.

Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-07-28 17:46:14 -04:00
Bart Van Assche 6b99013957 dm-snap: Combine request operation type and flags
Pass the request operation and its flags as a single argument to improve
kernel code uniformity.

Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-29-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-14 12:14:31 -06:00
Bart Van Assche 581075e4f6 dm/core: Reduce the size of struct dm_io_request
Combine the bi_op and bi_op_flags into the bi_opf member. Use the new
blk_opf_t type to improve static type checking. This patch does not
change any functionality.

Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-22-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-14 12:14:31 -06:00
Tushar Sugandhi 8ec456629d dm: update target status functions to support IMA measurement
For device mapper targets to take advantage of IMA's measurement
capabilities, the status functions for the individual targets need to be
updated to handle the status_type_t case for value STATUSTYPE_IMA.

Update status functions for the following target types, to log their
respective attributes to be measured using IMA.
 01. cache
 02. crypt
 03. integrity
 04. linear
 05. mirror
 06. multipath
 07. raid
 08. snapshot
 09. striped
 10. verity

For rest of the targets, handle the STATUSTYPE_IMA case by setting the
measurement buffer to NULL.

For IMA to measure the data on a given system, the IMA policy on the
system needs to be updated to have the following line, and the system
needs to be restarted for the measurements to take effect.

/etc/ima/ima-policy
 measure func=CRITICAL_DATA label=device-mapper template=ima-buf

The measurements will be reflected in the IMA logs, which are located at:

/sys/kernel/security/integrity/ima/ascii_runtime_measurements
/sys/kernel/security/integrity/ima/binary_runtime_measurements

These IMA logs can later be consumed by various attestation clients
running on the system, and send them to external services for attesting
the system.

The DM target data measured by IMA subsystem can alternatively
be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with
DM_TABLE_STATUS_CMD.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-08-10 13:34:23 -04:00
Matthew Wilcox (Oracle) 7a35693adc dm: replace dm_vcalloc()
Use kvcalloc or kvmalloc_array instead (depending whether zeroing is
useful).

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-04-19 13:13:26 -04:00
Qinglang Miao 7d837c0dd9 dm snap persistent: simplify area_io()
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-09-29 16:33:12 -04:00
Linus Torvalds 99ea1521a0 Remove uninitialized_var() macro for v5.9-rc1
- Clean up non-trivial uses of uninitialized_var()
 - Update documentation and checkpatch for uninitialized_var() removal
 - Treewide removal of uninitialized_var()
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Merge tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull uninitialized_var() macro removal from Kees Cook:
 "This is long overdue, and has hidden too many bugs over the years. The
  series has several "by hand" fixes, and then a trivial treewide
  replacement.

   - Clean up non-trivial uses of uninitialized_var()

   - Update documentation and checkpatch for uninitialized_var() removal

   - Treewide removal of uninitialized_var()"

* tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  compiler: Remove uninitialized_var() macro
  treewide: Remove uninitialized_var() usage
  checkpatch: Remove awareness of uninitialized_var() macro
  mm/debug_vm_pgtable: Remove uninitialized_var() usage
  f2fs: Eliminate usage of uninitialized_var() macro
  media: sur40: Remove uninitialized_var() usage
  KVM: PPC: Book3S PR: Remove uninitialized_var() usage
  clk: spear: Remove uninitialized_var() usage
  clk: st: Remove uninitialized_var() usage
  spi: davinci: Remove uninitialized_var() usage
  ide: Remove uninitialized_var() usage
  rtlwifi: rtl8192cu: Remove uninitialized_var() usage
  b43: Remove uninitialized_var() usage
  drbd: Remove uninitialized_var() usage
  x86/mm/numa: Remove uninitialized_var() usage
  docs: deprecated.rst: Add uninitialized_var()
2020-08-04 13:49:43 -07:00
Kees Cook 3f649ab728 treewide: Remove uninitialized_var() usage
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-16 12:35:15 -07:00
Christoph Hellwig ed00aabd5e block: rename generic_make_request to submit_bio_noacct
generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Mikulas Patocka ad6bf88a6c block: fix an integer overflow in logical block size
Logical block size has type unsigned short. That means that it can be at
most 32768. However, there are architectures that can run with 64k pages
(for example arm64) and on these architectures, it may be possible to
create block devices with 64k block size.

For exmaple (run this on an architecture with 64k pages):

Mount will fail with this error because it tries to read the superblock using 2-sector
access:
  device-mapper: writecache: I/O is not aligned, sector 2, size 1024, block size 65536
  EXT4-fs (dm-0): unable to read superblock

This patch changes the logical block size from unsigned short to unsigned
int to avoid the overflow.

Cc: stable@vger.kernel.org
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-15 21:43:09 -07:00
Mikulas Patocka afa53df869 dm bufio: move dm-bufio.h to include/linux/
Move dm-bufio.h to include/linux/ so that external GPL'd DM target
modules can use it.

It is better to allow the use of dm-bufio than force external modules
to implement the equivalent buffered IO mechanism in some new way.  The
hope is this will encourage the use of dm-bufio; which will then make it
easier for a GPL'd external DM target module to be included upstream.

A couple dm-bufio EXPORT_SYMBOL exports have also been updated to use
EXPORT_SYMBOL_GPL.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-04-03 15:04:23 -04:00
Jan Kara ff0361b34a dm: make flush bios explicitly sync
Commit b685d3d65a ("block: treat REQ_FUA and REQ_PREFLUSH as
synchronous") removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
definitions.  generic_make_request_checks() however strips REQ_FUA and
REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
write cache and thus write effectively becomes asynchronous which can
lead to performance regressions.

Fix the problem by making sure all bios which are synchronous are
properly marked with REQ_SYNC.

Fixes: b685d3d65a ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous")
Cc: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-05-31 10:50:23 -04:00
Christoph Hellwig 70fd76140a block,fs: use REQ_* flags directly
Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-01 09:43:26 -06:00
Mike Christie e6047149db dm: use bio op accessors
Separate the op from the rq_flag_bits and have dm
set/get the bio using bio_set_op_attrs/bio_op.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Mikulas Patocka 385277bfb5 dm snapshot: fix hung bios when copy error occurs
When there is an error copying a chunk dm-snapshot can incorrectly hold
associated bios indefinitely, resulting in hung IO.

The function copy_callback sets pe->error if there was error copying the
chunk, and then calls complete_exception.  complete_exception calls
pending_complete on error, otherwise it calls commit_exception with
commit_callback (and commit_callback calls complete_exception).

The persistent exception store (dm-snap-persistent.c) assumes that calls
to prepare_exception and commit_exception are paired.
persistent_prepare_exception increases ps->pending_count and
persistent_commit_exception decreases it.

If there is a copy error, persistent_prepare_exception is called but
persistent_commit_exception is not.  This results in the variable
ps->pending_count never returning to zero and that causes some pending
exceptions (and their associated bios) to be held forever.

Fix this by unconditionally calling commit_exception regardless of
whether the copy was successful.  A new "valid" parameter is added to
commit_exception -- when the copy fails this parameter is set to zero so
that the chunk that failed to copy (and all following chunks) is not
recorded in the snapshot store.  Also, remove commit_callback now that
it is merely a wrapper around pending_complete.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2016-01-08 20:03:05 -05:00
Linus Torvalds e0700ce709 - 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.
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Merge tag 'dm-4.4-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

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
2015-11-04 21:19:53 -08:00
Mikulas Patocka a3d939ae7b dm: convert ffs to __ffs
ffs counts bit starting with 1 (for the least significant bit), __ffs
counts bits starting with 0. This patch changes various occurrences of ffs
to __ffs and removes subtraction of 1 from the result.

Note that __ffs (unlike ffs) is not defined when called with zero
argument, but it is not called with zero argument in any of these cases.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:01 -04:00
Sudip Mukherjee a2a678ed4d dm snapshot persistent: fix missing cleanup in persistent_ctr error path
If an unsupported option is given then the early return from
persistent_ctr() leaked memory allocated for the 'pstore' and never
destroyed the 'metadata_wq'.

Fixes: b0d3cc011e ("dm snapshot: add new persistent store option to support overflow")
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-13 12:20:54 -04:00
Mike Snitzer b0d3cc011e dm snapshot: add new persistent store option to support overflow
Commit 76c44f6d80 introduced the possibly for "Overflow" to be reported
by the snapshot device's status.  Older userspace (e.g. lvm2) does not
handle the "Overflow" status response.

Fix this incompatibility by requiring newer userspace code, that can
cope with "Overflow", request the persistent store with overflow support
by using "PO" (Persistent with Overflow) for the snapshot store type.

Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Fixes: 76c44f6d80 ("dm snapshot: don't invalidate on-disk image on snapshot write overflow")
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-09 16:57:03 -04:00
viresh kumar fc0a446152 dm: remove unlikely() before IS_ERR()
IS_ERR() already contains an 'unlikely' compiler flag so there is no
need to do that again from IS_ERR() callers.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-08-12 11:32:21 -04:00
Markus Elfring 0c8f86322f dm snapshot: remove unnecessary NULL checks before vfree() calls
The vfree() function performs input parameter validation.
Thus the NULL pointer test around vfree() calls is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-09 13:06:49 -05:00
Mikulas Patocka 2c945820ca dm snapshot: fix metadata corruption
Commit 55494bf294 ("dm snapshot: use dm-bufio") broke snapshots.
Before that 3.14-rc1 commit, loading a snapshot's list of exceptions
involved reading exception areas one by one into ps->area and inserting
those exceptions into the hash table.  Commit 55494bf294 changed
it so that dm-bufio with prefetch is used to load exceptions in batchs.
Exceptions are loaded correctly, but ps->area is left uninitialized.
When a new exception is allocated, it is stored in this uninitialized
ps->area which will be written to the disk.  This causes metadata
corruption.

Fix this corruption by copying the last area that was read via dm-bufio
into ps->area.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-03 17:58:13 -05:00
Mikulas Patocka 55b082e614 dm snapshot: use dm-bufio prefetch
This patch modifies dm-snapshot so that it prefetches the buffers when
loading the exceptions.

The number of buffers read ahead is specified in the DM_PREFETCH_CHUNKS
macro.  The current value for DM_PREFETCH_CHUNKS (12) was found to
provide the best performance on a single 15k SCSI spindle.  In the
future we may modify this default or make it configurable.

Also, introduce the function dm_bufio_set_minimum_buffers to setup
bufio's number of internal buffers before freeing happens.  dm-bufio may
hold more buffers if enough memory is available.  There is no guarantee
that the specified number of buffers will be available - if you need a
guarantee, use the argument reserved_buffers for
dm_bufio_client_create.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-14 23:23:03 -05:00
Mikulas Patocka 55494bf294 dm snapshot: use dm-bufio
Use dm-bufio for initial loading of the exceptions.
Introduce a new function dm_bufio_forget that frees the given buffer.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-14 23:23:02 -05:00
Mikulas Patocka 2cadabd512 dm snapshot: prepare for switch to using dm-bufio
Change the functions get_exception, read_exception and insert_exceptions
so that ps->area is passed as an argument.

This patch doesn't change any functionality, but it refactors the code
to allow for a cleaner switch over to using dm-bufio.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-14 13:38:32 -05:00
Chuansheng Liu c1a6416021 dm snapshot: call destroy_work_on_stack() to pair with INIT_WORK_ONSTACK()
In case CONFIG_DEBUG_OBJECTS_WORK is defined, it is needed to
call destroy_work_on_stack() which frees the debug object to pair
with INIT_WORK_ONSTACK().

Signed-off-by: Liu, Chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-07 10:31:34 -05:00
Mikulas Patocka e9c6a18264 dm snapshot: fix data corruption
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>
2013-10-16 03:17:47 +01:00
Mikulas Patocka 5ea330a75b dm snapshot: workaround for a false positive lockdep warning
The kernel reports a lockdep warning if a snapshot is invalidated because
it runs out of space.

The lockdep warning was triggered by commit 0976dfc1d0
("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+
2013-09-20 10:36:34 -04:00
Paul Gortmaker daaa5f7cbe md: Add in export.h for files using EXPORT_SYMBOL
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>
2011-10-31 19:31:19 -04:00
Jonathan Brassow a2d2b0345a dm snapshot: style cleanups
Coding style cleanups.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
2011-08-02 12:32:03 +01:00
Joe Perches e29e65aacb dm: use vzalloc
Use vzalloc() instead of vmalloc()+memset().

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02 12:32:02 +01:00
Alasdair G Kergon 283a8328ca dm: suppress endian warnings
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>
2011-08-02 12:32:01 +01:00
Mikulas Patocka 762a80d9fc dm snapshot: flush disk cache when merging
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>
2011-08-02 12:32:00 +01:00
Mikulas Patocka bda8efec5c dm io: use fixed initial mempool size
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>
2011-05-29 13:03:09 +01:00
Tejun Heo 239c8dd533 dm snapshot: persistent make metadata_wq multithreaded
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>
2011-01-13 19:59:59 +00:00
Tejun Heo 4d4d66ab53 dm: convert workqueues to alloc_ordered
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>
2011-01-13 19:59:57 +00:00
Andrew Morton ca1cab37d9 workqueues: s/ON_STACK/ONSTACK/
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>
2010-10-26 16:52:14 -07:00
Tejun Heo d87f4c14f2 dm: implement REQ_FLUSH/FUA support for bio-based dm
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>
2010-09-10 12:35:38 +02:00
Tomohiro Kusumi 87c961cb74 dm snapshot: persistent use define for disk header chunk size
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>
2010-08-12 04:13:59 +01:00
Mike Snitzer 55f67f2ded dm snapshot: persistent annotate work_queue as on stack
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>
2010-02-16 18:42:51 +00:00
Mikulas Patocka 4454a6216f dm exception store: add merge specific methods
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>
2009-12-10 23:52:29 +00:00
Mike Snitzer fc56f6fbcc dm snapshot: move cow ref from exception store to snap core
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>
2009-12-10 23:52:12 +00:00
Mike Snitzer 985903bb3a dm snapshot: add allocated metadata to snapshot status
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>
2009-12-10 23:52:11 +00:00
Jon Brassow 1d4989c858 dm snapshot: rename dm_snap_exception to dm_exception
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>
2009-12-10 23:52:10 +00:00
Jon Brassow f5acc83428 dm snapshot: avoid else clause in persistent_read_metadata
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>
2009-12-10 23:52:07 +00:00
Mikulas Patocka df96eee679 dm snapshot: use unsigned integer chunk size
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>
2009-10-16 23:18:17 +01:00
Mikulas Patocka ae0b7448e9 dm snapshot: fix on disk chunk size validation
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>
2009-09-04 20:40:43 +01:00
Mikulas Patocka 61578dcd3f dm snapshot: fix header corruption race on invalidation
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>
2009-09-04 20:40:39 +01:00
Mikulas Patocka 02d2fd31de dm snapshot: refactor zero_disk_area to use chunk_io
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>
2009-09-04 20:40:37 +01:00