01 Nov, 2011
2 commits
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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.txtSigned-off-by: Joe Thornber
Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon -
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 deadlocksCurrently, 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
Signed-off-by: Alasdair G Kergon
02 Aug, 2011
1 commit
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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
Signed-off-by: Alasdair G Kergon
24 Mar, 2011
1 commit
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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
Signed-off-by: Alasdair G Kergon
14 Jan, 2011
1 commit
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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: raid \
2: \
3: ..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 in sectors.
[[no]sync] Force/Prevent RAID initialization
[rebuild ] Rebuild the drive indicated by the index
[daemon_sleep ] Time between bitmap daemon work to clear bits
[min_recovery_rate ] Throttle RAID initialization
[max_recovery_rate ] Throttle RAID initialization
[max_write_behind ] See '-write-behind=' (man mdadm)
[stripe_cache ] Stripe cache size for higher RAIDsLine 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 - 8:81Performing 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: raid \
2: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
Signed-off-by: Jonathan Brassow
Signed-off-by: Mike Snitzer
Signed-off-by: Alasdair G Kergon
09 Aug, 2010
1 commit
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Conflicts:
drivers/md/Makefile
lib/raid6/unroll.pl
18 May, 2010
1 commit
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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
Signed-off-by: NeilBrown
14 Dec, 2009
1 commit
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Make it clear in the config message that MD_MULTIPATH is not under
active development.Cc: Oren Held
Signed-off-by: NeilBrown
30 Oct, 2009
1 commit
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Signed-off-by: David Woodhouse
29 Oct, 2009
1 commit
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We'll want to use these in btrfs too.
Signed-off-by: David Woodhouse
09 Sep, 2009
1 commit
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Conflicts:
crypto/async_tx/async_xor.c
drivers/dma/ioat/dma_v2.h
drivers/dma/ioat/pci.c
drivers/md/raid5.c
30 Aug, 2009
3 commits
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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
Signed-off-by: Dan Williams -
[ 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 correctThe 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
Signed-off-by: Yuri Tikhonov
Signed-off-by: Ilya Yanok
Signed-off-by: Dan Williams -
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
Acked-by: Maciej Sosnowski
Signed-off-by: Dan Williams
22 Jun, 2009
3 commits
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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
Cc: Evgeniy Polyakov
Signed-off-by: Alasdair G Kergon -
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
Signed-off-by: Jun'ichi Nomura
Signed-off-by: Alasdair G Kergon -
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.htmlSigned-off-by: Stefan Bader
Signed-off-by: Kiyoshi Ueda
Signed-off-by: Jun'ichi Nomura
Signed-off-by: Alasdair G Kergon
31 Mar, 2009
2 commits
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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
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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
compileSigned-off-by: Dan Williams
Signed-off-by: NeilBrown
12 Oct, 2008
2 commits
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Signed-off-by: Alan Jenkins
Signed-off-by: Ingo Molnar -
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
Acked-by: NeilBrown
15 Jul, 2008
1 commit
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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
Reported-by: Randy Dunlap
Reported-by: Andrew Morton
Signed-off-by: James Bottomley
05 Jun, 2008
2 commits
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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
Acked-by: Alasdair G Kergon
Signed-off-by: James Bottomley -
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
Signed-off-by: Mike Christie
Acked-by: Alasdair G Kergon
Signed-off-by: James Bottomley
08 Feb, 2008
1 commit
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Drop the EXPERIMENTAL tag from well-established device-mapper targets, so
the newer ones stand out better.Signed-off-by: Alasdair G Kergon
21 Dec, 2007
1 commit
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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
Signed-off-by: Alasdair G Kergon
20 Oct, 2007
2 commits
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This patch adds a uevent skeleton to device-mapper.
Signed-off-by: Mike Anderson
Signed-off-by: Alasdair G Kergon -
This patch adds the most basic dm-multipath hardware support for the
HP active/passive arrays.Signed-off-by: Dave Wysochanski
Signed-off-by: Mike Christie
Acked-by: Chandra Seetharaman
Signed-off-by: Alasdair G Kergon
25 Aug, 2007
1 commit
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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
[ Tested and Verified by Chandra Seetharaman ]
Acked-by: Chandra Seetharaman
Signed-off-by: Linus Torvalds
18 Jul, 2007
1 commit
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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
Acked-by: Neil Brown
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Jul, 2007
1 commit
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* '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
...
13 Jul, 2007
3 commits
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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 Brownasync_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_(..., 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, );
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_(chan, len, int_en) : NULL;if (tx) { /* run 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 synchronously */
...
...
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 availableDetails:
* 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
Signed-off-by: Dan Williams
Acked-By: NeilBrown -
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 BunkCc: Adrian Bunk
Cc: NeilBrown
Cc: Herbert Xu
Signed-off-by: Dan Williams -
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
Signed-off-by: Mike Christie
Signed-off-by: Alasdair G Kergon
Signed-off-by: Linus Torvalds
10 May, 2007
1 commit
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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
Signed-off-by: Milan Broz
Signed-off-by: Alasdair G Kergon
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Dec, 2006
1 commit
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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
Signed-off-by: Linus Torvalds
03 Oct, 2006
2 commits
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I have had enough success reports not to believe that this is safe for 2.6.19.
Signed-off-by: Neil Brown
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add CONFIG_DM_DEBUG and DMDEBUG() macro.
Signed-off-by: Bryn Reeves
Signed-off-by: Alasdair G Kergon
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Oct, 2006
1 commit
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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
Signed-off-by: Jens Axboe
27 Jun, 2006
1 commit
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RAID5 recently changed to RAID456
Signed-off-by: Neil Brown
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
