Commit graph

48 commits

Author SHA1 Message Date
Mikulas Patocka
a4ffc15219 dm: add verity target
This device-mapper target creates a read-only device that transparently
validates the data on one underlying device against a pre-generated tree
of cryptographic checksums stored on a second device.

Two checksum device formats are supported: version 0 which is already
shipping in Chromium OS and version 1 which incorporates some
improvements.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Elly Jones <ellyjones@chromium.org>
Cc: Milan Broz <mbroz@redhat.com>
Cc: Olof Johansson <olofj@chromium.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-03-28 18:43:38 +01:00
Alasdair G Kergon
035220b33d dm raid: no longer experimental
The dm raid module (using md) is becoming the preferred way of creating long-lived
mirrors through userspace LVM so remove the EXPERIMENTAL tag.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-03-28 18:41:24 +01:00
Alasdair G Kergon
e0b215da8f dm uevent: no longer experimental
Drop EXPERIMENTAL tag from dm-uevent.

It's not changed for a while and some userspace tools are relying upon it.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2012-03-28 18:41:24 +01:00
Joe Thornber
991d9fa02d dm: add thin provisioning target
Initial EXPERIMENTAL implementation of device-mapper thin provisioning
with snapshot support.  The 'thin' target is used to create instances of
the virtual devices that are hosted in the 'thin-pool' target.  The
thin-pool target provides data sharing among devices.  This sharing is
made possible using the persistent-data library in the previous patch.

The main highlight of this implementation, compared to the previous
implementation of snapshots, is that it allows many virtual devices to
be stored on the same data volume, simplifying administration and
allowing sharing of data between volumes (thus reducing disk usage).

Another big feature is support for arbitrary depth of recursive
snapshots (snapshots of snapshots of snapshots ...).  The previous
implementation of snapshots did this by chaining together lookup tables,
and so performance was O(depth).  This new implementation uses a single
data structure so we don't get this degradation with depth.

For further information and examples of how to use this, please read
Documentation/device-mapper/thin-provisioning.txt

Signed-off-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-10-31 20:21:18 +00:00
Mikulas Patocka
95d402f057 dm: add bufio
The dm-bufio interface allows you to do cached I/O on devices,
holding recently-read blocks in memory and performing delayed writes.

We don't use buffer cache or page cache already present in the kernel, because:
* we need to handle block sizes larger than a page
* we can't allocate memory to perform reads or we'd have deadlocks

Currently, when a cache is required, we limit its size to a fraction of
available memory.  Usage can be viewed and changed in
/sys/module/dm_bufio/parameters/ .

The first user is thin provisioning, but more dm users are planned.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-10-31 20:19:09 +00:00
Jonathan Brassow
b12d437b73 dm raid: support metadata devices
Add the ability to parse and use metadata devices to dm-raid.  Although
not strictly required, without the metadata devices, many features of
RAID are unavailable.  They are used to store a superblock and bitmap.

The role, or position in the array, of each device must be recorded in
its superblock.  This is to help with fault handling, array reshaping,
and sanity checks.  RAID 4/5/6 devices must be loaded in a specific order:
in this way, the 'array_position' field helps validate the correctness
of the mapping when it is loaded.  It can be used during reshaping to
identify which devices are added/removed.  Fault handling is impossible
without this field.  For example, when a device fails it is recorded in
the superblock.  If this is a RAID1 device and the offending device is
removed from the array, there must be a way during subsequent array
assembly to determine that the failed device was the one removed.  This
is done by correlating the 'array_position' field and the bit-field
variable 'failed_devices'.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02 12:32:07 +01:00
Josef Bacik
3407ef5262 dm: add flakey target
This target is the same as the linear target except that it returns I/O
errors periodically.  It's been found useful in simulating failing
devices for testing purposes.

I needed a dm target to do some failure testing on btrfs's raid code, and
Mike pointed me at this.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-03-24 13:54:24 +00:00
NeilBrown
9d09e663d5 dm: raid456 basic support
This patch is the skeleton for the DM target that will be
the bridge from DM to MD (initially RAID456 and later RAID1).  It
provides a way to use device-mapper interfaces to the MD RAID456
drivers.

As with all device-mapper targets, the nominal public interfaces are the
constructor (CTR) tables and the status outputs (both STATUSTYPE_INFO
and STATUSTYPE_TABLE).  The CTR table looks like the following:

1: <s> <l> raid \
2:	<raid_type> <#raid_params> <raid_params> \
3:	<#raid_devs> <meta_dev1> <dev1> .. <meta_devN> <devN>

Line 1 contains the standard first three arguments to any device-mapper
target - the start, length, and target type fields.  The target type in
this case is "raid".

Line 2 contains the arguments that define the particular raid
type/personality/level, the required arguments for that raid type, and
any optional arguments.  Possible raid types include: raid4, raid5_la,
raid5_ls, raid5_rs, raid6_zr, raid6_nr, and raid6_nc.  (again, raid1 is
planned for the future.)  The list of required and optional parameters
is the same for all the current raid types.  The required parameters are
positional, while the optional parameters are given as key/value pairs.
The possible parameters are as follows:
 <chunk_size>		Chunk size in sectors.
 [[no]sync]		Force/Prevent RAID initialization
 [rebuild <idx>]	Rebuild the drive indicated by the index
 [daemon_sleep <ms>]	Time between bitmap daemon work to clear bits
 [min_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
 [max_recovery_rate <kB/sec/disk>]	Throttle RAID initialization
 [max_write_behind <value>]		See '-write-behind=' (man mdadm)
 [stripe_cache <sectors>]		Stripe cache size for higher RAIDs

Line 3 contains the list of devices that compose the array in
metadata/data device pairs.  If the metadata is stored separately, a '-'
is given for the metadata device position.  If a drive has failed or is
missing at creation time, a '-' can be given for both the metadata and
data drives for a given position.

Examples:
# RAID4 - 4 data drives, 1 parity
# No metadata devices specified to hold superblock/bitmap info
# Chunk size of 1MiB
# (Lines separated for easy reading)
0 1960893648 raid \
	raid4 1 2048 \
	5 - 8:17 - 8:33 - 8:49 - 8:65 - 8:81

# RAID4 - 4 data drives, 1 parity (no metadata devices)
# Chunk size of 1MiB, force RAID initialization,
#	min recovery rate at 20 kiB/sec/disk
0 1960893648 raid \
        raid4 4 2048 min_recovery_rate 20 sync\
        5 - 8:17 - 8:33 - 8:49 - 8:65 - 8:81

Performing a 'dmsetup table' should display the CTR table used to
construct the mapping (with possible reordering of optional
parameters).

Performing a 'dmsetup status' will yield information on the state and
health of the array.  The output is as follows:
1: <s> <l> raid \
2:	<raid_type> <#devices> <1 health char for each dev> <resync_ratio>

Line 1 is standard DM output.  Line 2 is best shown by example:
	0 1960893648 raid raid4 5 AAAAA 2/490221568
Here we can see the RAID type is raid4, there are 5 devices - all of
which are 'A'live, and the array is 2/490221568 complete with recovery.

Cc: linux-raid@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-01-13 20:00:02 +00:00
David Woodhouse
2144381da4 Merge branch 'async' of macbook:git/btrfs-unstable
Conflicts:
	drivers/md/Makefile
	lib/raid6/unroll.pl
2010-08-09 10:36:44 +01:00
NeilBrown
08fb730ca3 md: remove EXPERIMENTAL designation from RAID10
RAID10 has been available for quite a while now and is quite well
tested, so we can remove the EXPERIMENTAL designation.

Reported-by: Eric MSP Veith <eveith@wwweb-library.net>
Signed-off-by: NeilBrown <neilb@suse.de>
2010-05-18 15:27:58 +10:00
NeilBrown
93bd89a6d5 md: revise Kconfig help for MD_MULTIPATH
Make it clear in the config message that MD_MULTIPATH is not under
active development.

Cc: Oren Held <orenhe@il.ibm.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-12-14 12:51:41 +11:00
David Woodhouse
e5d84970a5 async_tx: Move ASYNC_RAID6_TEST option to crypto/async_tx/, fix dependencies
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-10-29 16:41:49 +00:00
David Woodhouse
f5e70d0fe3 md: Factor out RAID6 algorithms into lib/
We'll want to use these in btrfs too.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-10-29 14:38:47 +00:00
Dan Williams
bbb20089a3 Merge branch 'dmaengine' into async-tx-next
Conflicts:
	crypto/async_tx/async_xor.c
	drivers/dma/ioat/dma_v2.h
	drivers/dma/ioat/pci.c
	drivers/md/raid5.c
2009-09-08 17:55:21 -07:00
Dan Williams
07a3b417dc md/raid456: distribute raid processing over multiple cores
Now that the resources to handle stripe_head operations are allocated
percpu it is possible for raid5d to distribute stripe handling over
multiple cores.  This conversion also adds a call to cond_resched() in
the non-multicore case to prevent one core from getting monopolized for
raid operations.

Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-08-29 19:13:13 -07:00
Dan Williams
ac6b53b6e6 md/raid6: asynchronous raid6 operations
[ Based on an original patch by Yuri Tikhonov ]

The raid_run_ops routine uses the asynchronous offload api and
the stripe_operations member of a stripe_head to carry out xor+pq+copy
operations asynchronously, outside the lock.

The operations performed by RAID-6 are the same as in the RAID-5 case
except for no support of STRIPE_OP_PREXOR operations. All the others
are supported:
STRIPE_OP_BIOFILL
 - copy data into request buffers to satisfy a read request
STRIPE_OP_COMPUTE_BLK
 - generate missing blocks (1 or 2) in the cache from the other blocks
STRIPE_OP_BIODRAIN
 - copy data out of request buffers to satisfy a write request
STRIPE_OP_RECONSTRUCT
 - recalculate parity for new data that has entered the cache
STRIPE_OP_CHECK
 - verify that the parity is correct

The flow is the same as in the RAID-5 case, and reuses some routines, namely:
1/ ops_complete_postxor (renamed to ops_complete_reconstruct)
2/ ops_complete_compute (updated to set up to 2 targets uptodate)
3/ ops_run_check (renamed to ops_run_check_p for xor parity checks)

[neilb@suse.de: fixes to get it to pass mdadm regression suite]
Reviewed-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-08-29 19:13:12 -07:00
Dan Williams
cb3c82992f async_tx: raid6 recovery self test
Port drivers/md/raid6test/test.c to use the async raid6 recovery
routines.  This is meant as a unit test for raid6 acceleration drivers.  In
addition to the 16-drive test case this implements tests for the 4-disk and
5-disk special cases (dma devices can not generically handle less than 2
sources), and adds a test for the D+Q case.

Reviewed-by: Andre Noll <maan@systemlinux.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-08-29 19:09:28 -07:00
Jonthan Brassow
f5db4af466 dm raid1: add userspace log
This patch contains a device-mapper mirror log module that forwards
requests to userspace for processing.

The structures used for communication between kernel and userspace are
located in include/linux/dm-log-userspace.h.  Due to the frequency,
diversity, and 2-way communication nature of the exchanges between
kernel and userspace, 'connector' was chosen as the interface for
communication.

The first log implementations written in userspace - "clustered-disk"
and "clustered-core" - support clustered shared storage.   A userspace
daemon (in the LVM2 source code repository) uses openAIS/corosync to
process requests in an ordered fashion with the rest of the nodes in the
cluster so as to prevent log state corruption.  Other implementations
with no association to LVM or openAIS/corosync, are certainly possible.

(Imagine if two machines are writing to the same region of a mirror.
They would both mark the region dirty, but you need a cluster-aware
entity that can handle properly marking the region clean when they are
done.  Otherwise, you might clear the region when the first machine is
done, not the second.)

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22 10:12:35 +01:00
Kiyoshi Ueda
f392ba889b dm mpath: add service time load balancer
This patch adds a service time oriented dynamic load balancer,
dm-service-time, which selects the path with the shortest estimated
service time for the incoming I/O.
The service time is estimated by dividing the in-flight I/O size
by a performance value of each path.

The performance value can be given as a table argument at the table
loading time.  If no performance value is given, all paths are
considered equal.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22 10:12:28 +01:00
Kiyoshi Ueda
fd5e033908 dm mpath: add queue length load balancer
This patch adds a dynamic load balancer, dm-queue-length, which
balances the number of in-flight I/Os across the paths.

The code is based on the patch posted by Stefan Bader:
https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22 10:12:27 +01:00
NeilBrown
2cffc4a01d md: remove CONFIG_MD_RAID_RESHAPE config option.
This was only needed when the code was experimental.  Most of it
is well tested now, so the option is no longer useful.

Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31 15:27:05 +11:00
Dan Williams
f701d589aa md/raid6: move raid6 data processing to raid6_pq.ko
Move the raid6 data processing routines into a standalone module
(raid6_pq) to prepare them to be called from async_tx wrappers and other
non-md drivers/modules.  This precludes a circular dependency of raid456
needing the async modules for data processing while those modules in
turn depend on raid456 for the base level synchronous raid6 routines.

To support this move:
1/ The exportable definitions in raid6.h move to include/linux/raid/pq.h
2/ The raid6_call, recovery calls, and table symbols are exported
3/ Extra #ifdef __KERNEL__ statements to enable the userspace raid6test to
   compile

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2009-03-31 15:09:39 +11:00
Alan Jenkins
ce52aebd02 raid, fastboot: hide RAID autodetect option if MD is compiled as a module
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-12 08:25:14 -07:00
Arjan van de Ven
a364092a41 raid: make RAID autodetect default a KConfig option
RAID autodetect has the side effect of requiring synchronisation
of all device drivers, which can make the boot several seconds longer
(I've measured 7 on one of my laptops).... even for systems that don't
have RAID setup for the root filesystem (the only FS where this matters).

This patch makes the default for autodetect a config option; either way
the user can always override via the kernel command line.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: NeilBrown <neilb@suse.de>
2008-10-12 08:25:02 -07:00
Chandra Seetharaman
fe9233fb69 [SCSI] scsi_dh: fix kconfig related build errors
Do not automatically "select" SCSI_DH for dm-multipath. If SCSI_DH
doesn't exist,just do not allow  hardware handlers to be used.

Handle SCSI_DH being a module also. Make sure it doesn't allow DM_MULTIPATH
to be compiled in when SCSI_DH is a module.

[jejb: added comment for Kconfig syntax]
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-07-15 09:16:43 -05:00
Chandra Seetharaman
cb520223d7 [SCSI] scsi_dh: Remove hardware handlers from dm
This patch removes the 3 hardware handlers that currently exist
under dm as the functionality is moved to SCSI layer in the earlier
patches.

[jejb: removed more makefile hunks and rejection fixes]
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-06-05 09:23:41 -05:00
Chandra Seetharaman
cfae5c9bb6 [SCSI] scsi_dh: Use SCSI device handler in dm-multipath
This patch converts dm-mpath to use scsi device handlers instead of
dm's hardware handlers.

This patch does not add any new functionality. Old behaviors remain and
userspace tools work as is except that arguments supplied with hardware
handler are ignored.

One behavioral exception is: Activation of a path is synchronous in this
patch, opposed to the older behavior of being asynchronous (changed in
patch 07: scsi_dh: Add a single threaded workqueue for initializing a path)

Note: There is no need to get a reference for the device handler module
(as it was done in the dm hardware handler case) here as the reference
is held when the device was first found. Instead we check and make sure
that support for the specified device is present at table load time.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-06-05 09:23:41 -05:00
Alasdair G Kergon
0149e57fed dm: targets no longer experimental
Drop the EXPERIMENTAL tag from well-established device-mapper targets, so
the newer ones stand out better.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-02-08 02:10:32 +00:00
Paul Mundt
d1622e8909 dm mpath: hp requires scsi
With CONFIG_SCSI=n __scsi_print_sense() is never linked in.

drivers/built-in.o: In function `hp_sw_end_io':
dm-mpath-hp-sw.c:(.text+0x914f8): undefined reference to `__scsi_print_sense'

Caught with a randconfig on current git.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2007-12-20 17:32:09 +00:00
Mike Anderson
51e5b2bd34 dm: add uevent to core
This patch adds a uevent skeleton to device-mapper.

Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2007-10-20 02:01:24 +01:00
Dave Wysochanski
16ebbf3584 dm mpath: add hp handler
This patch adds the most basic dm-multipath hardware support for the
HP active/passive arrays.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2007-10-20 02:01:19 +01:00
Randy Dunlap
6e106b0d97 DM_MULTIPATH_RDAC: "scsi_normalize_sense" undefined
DM_MULTIPATH_RDAC uses SCSI API(s) and is for a SCSI device,
so add SCSI to its depends on to prevent build errors.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
[ Tested and Verified by Chandra Seetharaman ]
Acked-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-24 16:10:39 -07:00
Jan Engelhardt
afd44034ac Use menuconfig objects II - MD
Change Kconfig objects from "menu, config" into "menuconfig" so
that the user can disable the whole feature without having to
enter the menu first.

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:15 -07:00
Linus Torvalds
e030dbf91a Merge branch 'ioat-md-accel-for-linus' of git://lost.foo-projects.org/~dwillia2/git/iop
* 'ioat-md-accel-for-linus' of git://lost.foo-projects.org/~dwillia2/git/iop: (28 commits)
  ioatdma: add the unisys "i/oat" pci vendor/device id
  ARM: Add drivers/dma to arch/arm/Kconfig
  iop3xx: surface the iop3xx DMA and AAU units to the iop-adma driver
  iop13xx: surface the iop13xx adma units to the iop-adma driver
  dmaengine: driver for the iop32x, iop33x, and iop13xx raid engines
  md: remove raid5 compute_block and compute_parity5
  md: handle_stripe5 - request io processing in raid5_run_ops
  md: handle_stripe5 - add request/completion logic for async expand ops
  md: handle_stripe5 - add request/completion logic for async read ops
  md: handle_stripe5 - add request/completion logic for async check ops
  md: handle_stripe5 - add request/completion logic for async compute ops
  md: handle_stripe5 - add request/completion logic for async write ops
  md: common infrastructure for running operations with raid5_run_ops
  md: raid5_run_ops - run stripe operations outside sh->lock
  raid5: replace custom debug PRINTKs with standard pr_debug
  raid5: refactor handle_stripe5 and handle_stripe6 (v3)
  async_tx: add the async_tx api
  xor: make 'xor_blocks' a library routine for use with async_tx
  dmaengine: make clients responsible for managing channels
  dmaengine: refactor dmaengine around dma_async_tx_descriptor
  ...
2007-07-13 10:52:27 -07:00
Dan Williams
9bc89cd82d async_tx: add the async_tx api
The async_tx api provides methods for describing a chain of asynchronous
bulk memory transfers/transforms with support for inter-transactional
dependencies.  It is implemented as a dmaengine client that smooths over
the details of different hardware offload engine implementations.  Code
that is written to the api can optimize for asynchronous operation and the
api will fit the chain of operations to the available offload resources. 
 
	I imagine that any piece of ADMA hardware would register with the
	'async_*' subsystem, and a call to async_X would be routed as
	appropriate, or be run in-line. - Neil Brown

async_tx exploits the capabilities of struct dma_async_tx_descriptor to
provide an api of the following general format:

struct dma_async_tx_descriptor *
async_<operation>(..., struct dma_async_tx_descriptor *depend_tx,
			dma_async_tx_callback cb_fn, void *cb_param)
{
	struct dma_chan *chan = async_tx_find_channel(depend_tx, <operation>);
	struct dma_device *device = chan ? chan->device : NULL;
	int int_en = cb_fn ? 1 : 0;
	struct dma_async_tx_descriptor *tx = device ?
		device->device_prep_dma_<operation>(chan, len, int_en) : NULL;

	if (tx) { /* run <operation> asynchronously */
		...
		tx->tx_set_dest(addr, tx, index);
		...
		tx->tx_set_src(addr, tx, index);
		...
		async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
	} else { /* run <operation> synchronously */
		...
		<operation>
		...
		async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
	}

	return tx;
}

async_tx_find_channel() returns a capable channel from its pool.  The
channel pool is organized as a per-cpu array of channel pointers.  The
async_tx_rebalance() routine is tasked with managing these arrays.  In the
uniprocessor case async_tx_rebalance() tries to spread responsibility
evenly over channels of similar capabilities.  For example if there are two
copy+xor channels, one will handle copy operations and the other will
handle xor.  In the SMP case async_tx_rebalance() attempts to spread the
operations evenly over the cpus, e.g. cpu0 gets copy channel0 and xor
channel0 while cpu1 gets copy channel 1 and xor channel 1.  When a
dependency is specified async_tx_find_channel defaults to keeping the
operation on the same channel.  A xor->copy->xor chain will stay on one
channel if it supports both operation types, otherwise the transaction will
transition between a copy and a xor resource.

Currently the raid5 implementation in the MD raid456 driver has been
converted to the async_tx api.  A driver for the offload engines on the
Intel Xscale series of I/O processors, iop-adma, is provided in a later
commit.  With the iop-adma driver and async_tx, raid456 is able to offload
copy, xor, and xor-zero-sum operations to hardware engines.
 
On iop342 tiobench showed higher throughput for sequential writes (20 - 30%
improvement) and sequential reads to a degraded array (40 - 55%
improvement).  For the other cases performance was roughly equal, +/- a few
percentage points.  On a x86-smp platform the performance of the async_tx
implementation (in synchronous mode) was also +/- a few percentage points
of the original implementation.  According to 'top' on iop342 CPU
utilization drops from ~50% to ~15% during a 'resync' while the speed
according to /proc/mdstat doubles from ~25 MB/s to ~50 MB/s.
 
The tiobench command line used for testing was: tiobench --size 2048
--block 4096 --block 131072 --dir /mnt/raid --numruns 5
* iop342 had 1GB of memory available

Details:
* if CONFIG_DMA_ENGINE=n the asynchronous path is compiled away by making
  async_tx_find_channel a static inline routine that always returns NULL
* when a callback is specified for a given transaction an interrupt will
  fire at operation completion time and the callback will occur in a
  tasklet.  if the the channel does not support interrupts then a live
  polling wait will be performed
* the api is written as a dmaengine client that requests all available
  channels
* In support of dependencies the api implicitly schedules channel-switch
  interrupts.  The interrupt triggers the cleanup tasklet which causes
  pending operations to be scheduled on the next channel
* Xor engines treat an xor destination address differently than a software
  xor routine.  To the software routine the destination address is an implied
  source, whereas engines treat it as a write-only destination.  This patch
  modifies the xor_blocks routine to take a an explicit destination address
  to mirror the hardware.

Changelog:
* fixed a leftover debug print
* don't allow callbacks in async_interrupt_cond
* fixed xor_block changes
* fixed usage of ASYNC_TX_XOR_DROP_DEST
* drop dma mapping methods, suggested by Chris Leech
* printk warning fixups from Andrew Morton
* don't use inline in C files, Adrian Bunk
* select the API when MD is enabled
* BUG_ON xor source counts <= 1
* implicitly handle hardware concerns like channel switching and
  interrupts, Neil Brown
* remove the per operation type list, and distribute operation capabilities
  evenly amongst the available channels
* simplify async_tx_find_channel to optimize the fast path
* introduce the channel_table_initialized flag to prevent early calls to
  the api
* reorganize the code to mimic crypto
* include mm.h as not all archs include it in dma-mapping.h
* make the Kconfig options non-user visible, Adrian Bunk
* move async_tx under crypto since it is meant as 'core' functionality, and
  the two may share algorithms in the future
* move large inline functions into c files
* checkpatch.pl fixes
* gpl v2 only correction

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-By: NeilBrown <neilb@suse.de>
2007-07-13 08:06:14 -07:00
Dan Williams
685784aaf3 xor: make 'xor_blocks' a library routine for use with async_tx
The async_tx api tries to use a dma engine for an operation, but will fall
back to an optimized software routine otherwise.  Xor support is
implemented using the raid5 xor routines.  For organizational purposes this
routine is moved to a common area.

The following fixes are also made:
* rename xor_block => xor_blocks, suggested by Adrian Bunk
* ensure that xor.o initializes before md.o in the built-in case
* checkpatch.pl fixes
* mark calibrate_xor_blocks __init, Adrian Bunk

Cc: Adrian Bunk <bunk@stusta.de>
Cc: NeilBrown <neilb@suse.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2007-07-13 08:06:14 -07:00
Chandra Seetharaman
dd172d72ad dm mpath: rdac
This patch supports LSI/Engenio devices in RDAC mode. Like dm-emc
it requires userspace support. In your multipath.conf file you must have:

path_checker            rdac
hardware_handler        "1 rdac"
prio_callout		"/sbin/mpath_prio_tpc /dev/%n"

And you also then must have a updated multipath tools release which
has rdac support.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-12 15:01:23 -07:00
Heinz Mauelshagen
26b9f22870 dm: delay target
New device-mapper target that can delay I/O (for testing).  Reads can be
separated from writes, redirected to different underlying devices and delayed
by differing amounts of time.

Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com>
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:47 -07:00
Herbert Xu
3263263f70 [CRYPTO] dm-crypt: Select CRYPTO_CBC
As CBC is the default chaining method for cryptoloop, we should select
it from cryptoloop to ease the transition.  Spotted by Rene Herman.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-10 10:18:57 -08:00
NeilBrown
14f50b49fd [PATCH] md: remove 'experimental' classification from raid5 reshape
I have had enough success reports not to believe that this is safe for 2.6.19.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03 08:04:18 -07:00
Bryn Reeves
cc1092019c [PATCH] dm: add debug macro
Add CONFIG_DM_DEBUG and DMDEBUG() macro.

Signed-off-by: Bryn Reeves <breeves@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03 08:04:15 -07:00
David Howells
9361401eb7 [PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer.  Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.

This patch does the following:

 (*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
     support.

 (*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
     an item that uses the block layer.  This includes:

     (*) Block I/O tracing.

     (*) Disk partition code.

     (*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.

     (*) The SCSI layer.  As far as I can tell, even SCSI chardevs use the
     	 block layer to do scheduling.  Some drivers that use SCSI facilities -
     	 such as USB storage - end up disabled indirectly from this.

     (*) Various block-based device drivers, such as IDE and the old CDROM
     	 drivers.

     (*) MTD blockdev handling and FTL.

     (*) JFFS - which uses set_bdev_super(), something it could avoid doing by
     	 taking a leaf out of JFFS2's book.

 (*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
     linux/elevator.h contingent on CONFIG_BLOCK being set.  sector_div() is,
     however, still used in places, and so is still available.

 (*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
     parts of linux/fs.h.

 (*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.

 (*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.

 (*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
     is not enabled.

 (*) fs/no-block.c is created to hold out-of-line stubs and things that are
     required when CONFIG_BLOCK is not set:

     (*) Default blockdev file operations (to give error ENODEV on opening).

 (*) Makes some /proc changes:

     (*) /proc/devices does not list any blockdevs.

     (*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.

 (*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.

 (*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
     given command other than Q_SYNC or if a special device is specified.

 (*) In init/do_mounts.c, no reference is made to the blockdev routines if
     CONFIG_BLOCK is not defined.  This does not prohibit NFS roots or JFFS2.

 (*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
     error ENOSYS by way of cond_syscall if so).

 (*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
     CONFIG_BLOCK is not set, since they can't then happen.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:31 +02:00
akpm@osdl.org
b3cc9ec76b [PATCH] md: Fix Kconfig error
RAID5 recently changed to RAID456

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:39 -07:00
Justin Piszcz
4d2554d045 [PATCH] md: md Kconfig speeling feex
I was experimenting with Linux SW raid today and found a spelling error when
reading the help menus...  (and fly spell found more).

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:39 -07:00
NeilBrown
16a53ecc35 [PATCH] md: merge raid5 and raid6 code
There is a lot of commonality between raid5.c and raid6main.c.  This patches
merges both into one module called raid456.  This saves a lot of code, and
paves the way for online raid5->raid6 migrations.

There is still duplication, e.g.  between handle_stripe5 and handle_stripe6.
This will probably be cleaned up later.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:37 -07:00
NeilBrown
6f91fe88e4 [PATCH] md: make sure 64bit fields in version-1 metadata are 64-bit aligned
reshape_position is a 64bit field that was not 64bit aligned.  So swap with
new_level.

NOTE: this is a user-visible change.  However:
  - The bad code has not appeared in a released kernel
  - This code is still marked 'experimental'
  - This only affects version-1 superblock, which are not in wide use
  - These field are only used (rather than simply reported) by user-space
    tools in extemely rare circumstances : after a reshape crashes in the
    first second of the reshape process.

So I believe that, at this stage, the change is safe.  Especially if people
heed the 'help' message on use mdadm-2.4.1.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-11 06:18:30 -07:00
NeilBrown
292695531a [PATCH] md: Final stages of raid5 expand code
This patch adds raid5_reshape and end_reshape which will start and finish the
reshape processes.

raid5_reshape is only enabled in CONFIG_MD_RAID5_RESHAPE is set, to discourage
accidental use.

Read the 'help' for the CONFIG_MD_RAID5_RESHAPE entry.

and Make sure that you have backups, just in case.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 08:45:01 -08:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00