Commit Graph

105 Commits

Author SHA1 Message Date
Jens Axboe 1eff9d322a block: rename bio bi_rw to bi_opf
Since commit 63a4cc2486, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-07 14:41:02 -06:00
Heinz Mauelshagen d41bfed091 dm raid: update Documentation about reshaping/takeover/additonal RAID types
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-06-14 18:52:12 -04:00
Mike Christie 28a8f0d317 block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSH
To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Eric Engestrom 52813d4046 dm stats: fix spelling mistake in Documentation
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-05-05 15:25:54 -04:00
Mike Snitzer 492d48db8d dm cache: update cache-policies.txt now that mq is an alias for smq
Also fix some typos and make all "smq" and "mq" references consistently
lowercase.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-05-05 15:25:53 -04:00
Joe Thornber 9ed84698fd dm cache: make the 'mq' policy an alias for 'smq'
smq seems to be performing better than the old mq policy in all
situations, as well as using a quarter of the memory.

Make 'mq' an alias for 'smq' when choosing a cache policy.  The tunables
that were present for the old mq are faked, and have no effect.  mq
should be considered deprecated now.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-03-10 17:12:08 -05:00
Sami Tolvanen 0cc37c2df4 dm verity: add ignore_zero_blocks feature
If ignore_zero_blocks is enabled dm-verity will return zeroes for blocks
matching a zero hash without validating the content.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:03 -05:00
Sami Tolvanen a739ff3f54 dm verity: add support for forward error correction
Add support for correcting corrupted blocks using Reed-Solomon.

This code uses RS(255, N) interleaved across data and hash
blocks. Each error-correcting block covers N bytes evenly
distributed across the combined total data, so that each byte is a
maximum distance away from the others. This makes it possible to
recover from several consecutive corrupted blocks with relatively
small space overhead.

In addition, using verity hashes to locate erasures nearly doubles
the effectiveness of error correction. Being able to detect
corrupted blocks also improves performance, because only corrupted
blocks need to corrected.

For a 2 GiB partition, RS(255, 253) (two parity bytes for each
253-byte block) can correct up to 16 MiB of consecutive corrupted
blocks if erasures can be located, and 8 MiB if they cannot, with
16 MiB space overhead.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-12-10 10:39:03 -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
Tomohiro Kusumi f49e869a61 dm delay: document that offsets are specified in sectors
Only delay params are mentioned in delay.txt.
Mention offsets just like documents for linear and flakey do.

Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:05 -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
Heinz Mauelshagen f15f4d7200 dm raid: document RAID 4/5/6 discard support
For RAID 4/5/6 data integrity reasons 'discard_zeroes_data' must work
properly.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-08-31 15:05:31 -04:00
Mikulas Patocka bd49784fd1 dm stats: report precise_timestamps and histogram in @stats_list output
If the user selected the precise_timestamps or histogram options, report
it in the @stats_list message output.

If the user didn't select these options, no extra tokens are reported,
thus it is backward compatible with old software that doesn't know about
precise timestamps and histogram.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.2
2015-08-18 17:20:03 -04:00
Mike Snitzer 255eac2005 dm cache: display 'needs_check' in status if it is set
There is currently no way to see that the needs_check flag has been set
in the metadata.  Display 'needs_check' in the cache status if it is set
in the cache metadata.

Also, update cache documentation.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 10:23:50 -04:00
Mike Snitzer e4c78e210d dm thin: display 'needs_check' in status if it is set
There is currently no way to see that the needs_check flag has been set
in the metadata.  Display 'needs_check' in the thin-pool status if it is
set in the thinp metadata.

Also, update thinp documentation.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 10:23:50 -04:00
Mikulas Patocka dfcfac3e4c dm stats: collect and report histogram of IO latencies
Add an option to dm statistics to collect and report a histogram of
IO latencies.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-06-17 12:40:40 -04:00
Mikulas Patocka c96aec344d dm stats: support precise timestamps
Make it possible to use precise timestamps with nanosecond granularity
in dm statistics.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-06-17 12:40:40 -04:00
Mike Snitzer bccab6a01a dm cache: switch the "default" cache replacement policy from mq to smq
The Stochastic multiqueue (SMQ) policy (vs MQ) offers the promise of
less memory utilization, improved performance and increased adaptability
in the face of changing workloads.  SMQ also does not have any
cumbersome tuning knobs.

Users may switch from "mq" to "smq" simply by appropriately reloading a
DM table that is using the cache target.  Doing so will cause all of the
mq policy's hints to be dropped.  Also, performance of the cache may
degrade slightly until smq recalculates the origin device's hotspots
that should be cached.

In the future the "mq" policy will just silently make use of "smq" and
the mq code will be removed.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2015-06-17 12:40:38 -04:00
Joe Thornber 028ae9f76f dm cache: add fail io mode and needs_check flag
If a cache metadata operation fails (e.g. transaction commit) the
cache's metadata device will abort the current transaction, set a new
needs_check flag, and the cache will transition to "read-only" mode.  If
aborting the transaction or setting the needs_check flag fails the cache
will transition to "fail-io" mode.

Once needs_check is set the cache device will not be allowed to
activate.  Activation requires write access to metadata.  Future work is
needed to add proper support for running the cache in read-only mode.

Once in fail-io mode the cache will report a status of "Fail".

Also, add commit() wrapper that will disallow commits if in read_only or
fail mode.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-06-11 17:13:00 -04:00
Heinz Mauelshagen 0cf4503174 dm raid: add support for the MD RAID0 personality
Add dm-raid access to the MD RAID0 personality to enable single zone
striping.

The following changes enable that access:
- add type definition to raid_types array
- make bitmap creation conditonal in super_validate(), because
  bitmaps are not allowed in raid0
- set rdev->sectors to the data image size in super_validate()
  to allow the raid0 personality to calculate the MD array
  size properly
- use mdddev(un)lock() functions instead of direct mutex_(un)lock()
  (wrapped in here because it's a trivial change)
- enhance raid_status() to always report full sync for raid0
  so that userspace checks for 100% sync will succeed and allow
  for resize (and takeover/reshape once added in future paches)
- enhance raid_resume() to not load bitmap in case of raid0
- add merge function to avoid data corruption (seen with readahead)
  that resulted from bio payloads that grew too large.  This problem
  did not occur with the other raid levels because it either did not
  apply without striping (raid1) or was avoided via stripe caching.
- raise version to 1.7.0 because of the raid0 API change

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:00 -04:00
Heinz Mauelshagen 0f4106b32f dm raid: fixup documentation for discard support
Remove comment above parse_raid_params() that claims
"devices_handle_discard_safely" is a table line argument when it is
actually is a module parameter.

Also, backfill dm-raid target version 1.6.0 documentation.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:18:59 -04:00
Milan Broz e44f23b32d dm crypt: update URLs to new cryptsetup project page
Cryptsetup home page moved to GitLab.
Also remove link to abandonded Truecrypt page.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:24 -04:00
Josef Bacik 0e9cebe724 dm: add log writes target
Introduce a new target that is meant for file system developers to test file
system integrity at particular points in the life of a file system.  We capture
all write requests and associated data and log them to a separate device
for later replay.  There is a userspace utility to do this replay.  The
idea behind this is to give file system developers a tool to verify that
the file system is always consistent.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Zach Brown <zab@zabbo.net>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:24 -04:00
Sami Tolvanen 65ff5b7ddf dm verity: add error handling modes for corrupted blocks
Add device specific modes to dm-verity to specify how corrupted
blocks should be handled.  The following modes are defined:

  - DM_VERITY_MODE_EIO is the default behavior, where reading a
    corrupted block results in -EIO.

  - DM_VERITY_MODE_LOGGING only logs corrupted blocks, but does
    not block the read.

  - DM_VERITY_MODE_RESTART calls kernel_restart when a corrupted
    block is discovered.

In addition, each mode sends a uevent to notify userspace of
corruption and to allow further recovery actions.

The driver defaults to previous behavior (DM_VERITY_MODE_EIO)
and other modes can be enabled with an additional parameter to
the verity table.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:22 -04:00
Mike Snitzer 0e0e32c16c dm thin: remove stale 'trim' message documentation
The 'trim' message wasn't ever implemented.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:22 -04:00
Mike Snitzer e73f6e8a0d dm switch: fix Documentation to use plain text
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-03-31 12:03:49 -04:00
Mikulas Patocka 0f5d8e6ee7 dm crypt: add 'submit_from_crypt_cpus' option
Make it possible to disable offloading writes by setting the optional
'submit_from_crypt_cpus' table argument.

There are some situations where offloading write bios from the
encryption threads to a single thread degrades performance
significantly.

The default is to offload write bios to the same thread because it
benefits CFQ to have writes submitted using the same IO context.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:15 -05:00
Mikulas Patocka f3396c58fd dm crypt: use unbound workqueue for request processing
Use unbound workqueue by default so that work is automatically balanced
between available CPUs.  The original behavior of encrypting using the
same cpu that IO was submitted on can still be enabled by setting the
optional 'same_cpu_crypt' table argument.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:10:59 -05:00
Mike Snitzer f1afb36a61 dm cache policy mq: simplify ability to promote sequential IO to the cache
Before, if the user wanted sequential IO to be promoted to the cache
they'd have to set sequential_threshold to some nebulous large value.

Now, the user may easily disable sequential IO detection (and sequential
IO's implicit bypass of the cache) by setting sequential_threshold to 0.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:30 -05:00
Joe Thornber b155aa0e5a dm cache policy mq: tweak algorithm that decides when to promote a block
Rather than maintaining a separate promote_threshold variable that we
periodically update we now use the hit count of the oldest clean
block.  Also add a fudge factor to discourage demoting dirty blocks.

With some tests this has a sizeable difference, because the old code
was too eager to demote blocks.  For example, device-mapper-test-suite's
git_extract_cache_quick test goes from taking 190 seconds, to 142
(linear on spindle takes 250).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-10 15:25:29 -05:00
Mikulas Patocka 56b1ebf2d9 dm switch: efficiently support repetitive patterns
Add support for quickly loading a repetitive pattern into the
dm-switch target.

In the "set_regions_mappings" message, the user may now use "Rn,m" as
one of the arguments.  "n" and "m" are hexadecimal numbers.  The "Rn,m"
argument repeats the last "n" arguments in the following "m" slots.

For example:
dmsetup message switch 0 set_region_mappings 1000:1 :2 R2,10
is equivalent to
dmsetup message switch 0 set_region_mappings 1000:1 :2 :1 :2 :1 :2 :1 :2 \
:1 :2 :1 :2 :1 :2 :1 :2 :1 :2

Requested-by: Jay Wang <jwang@nimblestorage.com>
Tested-by: Jay Wang <jwang@nimblestorage.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-08-01 12:30:37 -04:00
Mike Snitzer 80c578930c dm thin: add 'no_space_timeout' dm-thin-pool module param
Commit 85ad643b ("dm thin: add timeout to stop out-of-data-space mode
holding IO forever") introduced a fixed 60 second timeout.  Users may
want to either disable or modify this timeout.

Allow the out-of-data-space timeout to be configured using the
'no_space_timeout' dm-thin-pool module param.  Setting it to 0 will
disable the timeout, resulting in IO being queued until more data space
is added to the thin-pool.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.14+
2014-05-20 14:30:36 -04:00
Joe Thornber eec40579d8 dm: add era target
dm-era is a target that behaves similar to the linear target.  In
addition it keeps track of which blocks were written within a user
defined period of time called an 'era'.  Each era target instance
maintains the current era as a monotonically increasing 32-bit
counter.

Use cases include tracking changed blocks for backup software, and
partially invalidating the contents of a cache to restore cache
coherency after rolling back a vendor snapshot.

dm-era is primarily expected to be paired with the dm-cache target.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27 16:56:23 -04:00
Mike Snitzer f6d16d3279 dm thin: fix Documentation for held metadata root feature
The Documentation for the thin provisioning target's held metadata root
feature was incorrect.  It is now available and the value for the held
metadata root is in block units (not 512b sectors).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-06 14:23:35 -05:00
Mike Snitzer 07f2b6e038 dm thin: ensure user takes action to validate data and metadata consistency
If a thin metadata operation fails the current transaction will abort,
whereby causing potential for IO layers up the stack (e.g. filesystems)
to have data loss.  As such, set THIN_METADATA_NEEDS_CHECK_FLAG in the
thin metadata's superblock which:
1) requires the user verify the thin metadata is consistent (e.g. use
   thin_check, etc)
2) suggests the user verify the thin data is consistent (e.g. use fsck)

The only way to clear the superblock's THIN_METADATA_NEEDS_CHECK_FLAG is
to run thin_repair.

On metadata operation failure: abort current metadata transaction, set
pool in read-only mode, and now set the needs_check flag.

As part of this change, constraints are introduced or relaxed:
* don't allow a pool to transition to write mode if needs_check is set
* don't allow data or metadata space to be resized if needs_check is set
* if a thin pool's metadata space is exhausted: the kernel will now
  force the user to take the pool offline for repair before the kernel
  will allow the metadata space to be extended.

Also, update Documentation to include information about when the thin
provisioning target commits metadata, how it handles metadata failures
and running out of space.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Joe Thornber <ejt@redhat.com>
2014-03-05 15:25:35 -05:00
Mike Snitzer 2e68c4e6ca dm cache: add policy name to status output
The cache's policy may have been established using the "default" alias,
which is currently the "mq" policy but the default policy may change in
the future.  It is useful to know exactly which policy is being used.

Add a 'real' member to the dm_cache_policy_type structure and have the
"default" dm_cache_policy_type point to the real "mq"
dm_cache_policy_type.  Update dm_cache_policy_get_name() to check if
real is set, if so report the name of the real policy (not the alias).

Requested-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-16 13:44:11 -05:00
Mike Snitzer 6a388618f1 dm cache: add block sizes and total cache blocks to status output
Improve cache_status to emit:
<metadata block size> <#used metadata blocks>/<#total metadata blocks>
<cache block size> <#used cache blocks>/<#total cache blocks>
...

Adding the block sizes allows for easier calculation of the overall size
of both the metadata and cache devices.  Adding <#total cache blocks>
provides useful context for how much of the cache is used.

Unfortunately these additions to the status will require updates to
users' scripts that monitor the cache status.  But these changes help
provide more comprehensive information about the cache device and will
simplify tools that are being developed to manage dm-cache devices --
because they won't need to issue 3 operations to cobble together the
information that we can easily provide via a single status ioctl.

While updating the status documentation in cache.txt spaces were
tabify'd.

Requested-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-01-10 10:24:33 -05:00
Joe Thornber 78e03d6973 dm cache policy mq: introduce three promotion threshold tunables
Internally the mq policy maintains a promotion threshold variable.  If
the hit count of a block not in the cache goes above this threshold it
gets promoted to the cache.

This patch introduces three new tunables that allow you to tweak the
promotion threshold by adding a small value.  These adjustments depend
on the io type:

   read_promote_adjustment:    READ io, default 4
   write_promote_adjustment:   WRITE io, default 8
   discard_promote_adjustment: READ/WRITE io to a discarded block, default 1

If you're trying to quickly warm a new cache device you may wish to
reduce these to encourage promotion.  Remember to switch them back to
their defaults after the cache fills though.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-07 10:14:33 -05:00
Mike Snitzer 787a996cb2 dm thin: add error_if_no_space feature
If the pool runs out of data or metadata space, the pool can either
queue or error the IO destined to the data device.  The default is to
queue the IO until more space is added.

An admin may now configure the pool to error IO when no space is
available by setting the 'error_if_no_space' feature when loading the
thin-pool table.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2014-01-07 10:14:30 -05:00
Mike Snitzer 83f539e1a4 dm cache: update Documentation for invalidate_cblocks's range syntax
The cache target's invalidate_cblocks message allows cache block
(cblock) ranges to be expressed with: <cblock start>-<cblock end>

The range's <cblock end> value is "one past the end", so the range
includes <cblock start> through <cblock end>-1.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2013-12-10 16:35:15 -05:00
Mike Snitzer 7b6b2bc98c dm cache: resolve small nits and improve Documentation
Document passthrough mode, cache shrinking, and cache invalidation.
Also, use strcasecmp() and hlist_unhashed().

Reported-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-12 13:11:09 -05:00
Joe Thornber 65790ff919 dm cache: add cache block invalidation support
Cache block invalidation is removing an entry from the cache without
writing it back.  Cache blocks can be invalidated via the
'invalidate_cblocks' message, which takes an arbitrary number of cblock
ranges:
   invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]*

E.g.
   dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-11 11:37:51 -05:00
Joe Thornber 2ee57d5873 dm cache: add passthrough mode
"Passthrough" is a dm-cache operating mode (like writethrough or
writeback) which is intended to be used when the cache contents are not
known to be coherent with the origin device.  It behaves as follows:

* All reads are served from the origin device (all reads miss the cache)
* All writes are forwarded to the origin device; additionally, write
  hits cause cache block invalidates

This mode decouples cache coherency checks from cache device creation,
largely to avoid having to perform coherency checks while booting.  Boot
scripts can create cache devices in passthrough mode and put them into
service (mount cached filesystems, for example) without having to worry
about coherency.  Coherency that exists is maintained, although the
cache will gradually cool as writes take place.

Later, applications can perform coherency checks, the nature of which
will depend on the type of the underlying storage.  If coherency can be
verified, the cache device can be transitioned to writethrough or
writeback mode while still warm; otherwise, the cache contents can be
discarded prior to transitioning to the desired operating mode.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-11 11:37:49 -05:00
Joe Thornber 01911c19be dm cache policy mq: implement writeback_work() and mq_{set,clear}_dirty()
There are now two multiqueues for in cache blocks.  A clean one and a
dirty one.

writeback_work comes from the dirty one.  Demotions come from the clean
one.

There are two benefits:
- Performance improvement, since demoting a clean block is a noop.
- The cache cleans itself when io load is light.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-09 18:20:25 -05:00
Milan Broz ed04d98169 dm crypt: add TCW IV mode for old CBC TCRYPT containers
dm-crypt can already activate TCRYPT (TrueCrypt compatible) containers
in LRW or XTS block encryption mode.

TCRYPT containers prior to version 4.1 use CBC mode with some additional
tweaks, this patch adds support for these containers.

This new mode is implemented using special IV generator named TCW
(TrueCrypt IV with whitening).  TCW IV only supports containers that are
encrypted with one cipher (Tested with AES, Twofish, Serpent, CAST5 and
TripleDES).

While this mode is legacy and is known to be vulnerable to some
watermarking attacks (e.g. revealing of hidden disk existence) it can
still be useful to activate old containers without using 3rd party
software or for independent forensic analysis of such containers.

(Both the userspace and kernel code is an independent implementation
based on the format documentation and it completely avoids use of
original source code.)

The TCW IV generator uses two additional keys: Kw (whitening seed, size
is always 16 bytes - TCW_WHITENING_SIZE) and Kiv (IV seed, size is
always the IV size of the selected cipher).  These keys are concatenated
at the end of the main encryption key provided in mapping table.

While whitening is completely independent from IV, it is implemented
inside IV generator for simplification.

The whitening value is always 16 bytes long and is calculated per sector
from provided Kw as initial seed, xored with sector number and mixed
with CRC32 algorithm.  Resulting value is xored with ciphertext sector
content.

IV is calculated from the provided Kiv as initial IV seed and xored with
sector number.

Detailed calculation can be found in the Truecrypt documentation for
version < 4.1 and will also be described on dm-crypt site, see:
http://code.google.com/p/cryptsetup/wiki/DMCrypt

The experimental support for activation of these containers is already
present in git devel brach of cryptsetup.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-09 18:20:20 -05:00
Mikulas Patocka fd2ed4d252 dm: add statistics support
Support the collection of I/O statistics on user-defined regions of
a DM device.  If no regions are defined no statistics are collected so
there isn't any performance impact.  Only bio-based DM devices are
currently supported.

Each user-defined region specifies a starting sector, length and step.
Individual statistics will be collected for each step-sized area within
the range specified.

The I/O statistics counters for each step-sized area of a region are
in the same format as /sys/block/*/stat or /proc/diskstats but extra
counters (12 and 13) are provided: total time spent reading and
writing in milliseconds.  All these counters may be accessed by sending
the @stats_print message to the appropriate DM device via dmsetup.

The creation of DM statistics will allocate memory via kmalloc or
fallback to using vmalloc space.  At most, 1/4 of the overall system
memory may be allocated by DM statistics.  The admin can see how much
memory is used by reading
/sys/module/dm_mod/parameters/stats_current_allocated_bytes

See Documentation/device-mapper/statistics.txt for more details.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-09-05 20:46:06 -04:00
Carlos Maiolino a561ddbec1 dm thin: add data block size limits to Documentation
Inform users that the data block size can't be any arbitrary number,
i.e. its value must be between 64KB and 1GB.  Also, it should be a
multiple of 64KB.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-23 09:02:14 -04:00
Mike Snitzer 0547304463 dm cache: add data block size limits to code and Documentation
Place upper bound on the cache's data block size (1GB).

Inform users that the data block size can't be any arbitrary number,
i.e. its value must be between 32KB and 1GB.  Also, it should be a
multiple of 32KB.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-23 09:02:13 -04:00
Mike Snitzer 66bb2644ca dm cache: document metadata device is exclussive to a cache
A cache's metadata device may not be shared by multiple cache devices.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-23 09:02:13 -04:00
Linus Torvalds 9903883f1d Add a device-mapper target called dm-switch to provide a multipath
framework for storage arrays that dynamically reconfigure their
 preferred paths for different device regions.
 
 Fix a bug in the verity target that prevented its use with some
 specific sizes of devices.
 
 Improve some locking mechanisms in the device-mapper core and bufio.
 
 Add Mike Snitzer as a device-mapper maintainer.
 
 A few more clean-ups and fixes.
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Merge tag 'dm-3.11-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm

Pull device-mapper changes from Alasdair G Kergon:
 "Add a device-mapper target called dm-switch to provide a multipath
  framework for storage arrays that dynamically reconfigure their
  preferred paths for different device regions.

  Fix a bug in the verity target that prevented its use with some
  specific sizes of devices.

  Improve some locking mechanisms in the device-mapper core and bufio.

  Add Mike Snitzer as a device-mapper maintainer.

  A few more clean-ups and fixes"

* tag 'dm-3.11-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
  dm: add switch target
  dm: update maintainers
  dm: optimize reorder structure
  dm: optimize use SRCU and RCU
  dm bufio: submit writes outside lock
  dm cache: fix arm link errors with inline
  dm verity: use __ffs and __fls
  dm flakey: correct ctr alloc failure mesg
  dm verity: remove pointless comparison
  dm: use __GFP_HIGHMEM in __vmalloc
  dm verity: fix inability to use a few specific devices sizes
  dm ioctl: set noio flag to avoid __vmalloc deadlock
  dm mpath: fix ioctl deadlock when no paths
2013-07-11 13:05:40 -07:00