Big change is new hot-replacement.
A slot in an array can hold 2 devices - one that
wants-replacement and one that is the replacement.
Once the replacement is built - either from the
original or (in the case of errors) from elsewhere,
the wants-replacement device will be removed.
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Merge tag 'md-3.3' of git://neil.brown.name/md
md update for 3.3
Big change is new hot-replacement.
A slot in an array can hold 2 devices - one that
wants-replacement and one that is the replacement.
Once the replacement is built - either from the
original or (in the case of errors) from elsewhere,
the wants-replacement device will be removed.
* tag 'md-3.3' of git://neil.brown.name/md: (36 commits)
md/raid1: Mark device want_replacement when we see a write error.
md/raid1: If there is a spare and a want_replacement device, start replacement.
md/raid1: recognise replacements when assembling arrays.
md/raid1: handle activation of replacement device when recovery completes.
md/raid1: Allow a failed replacement device to be removed.
md/raid1: Allocate spare to store replacement devices and their bios.
md/raid1: Replace use of mddev->raid_disks with conf->raid_disks.
md/raid10: If there is a spare and a want_replacement device, start replacement.
md/raid10: recognise replacements when assembling array.
md/raid10: Allow replacement device to be replace old drive.
md/raid10: handle recovery of replacement devices.
md/raid10: Handle replacement devices during resync.
md/raid10: writes should get directed to replacement as well as original.
md/raid10: allow removal of failed replacement devices.
md/raid10: preferentially read from replacement device if possible.
md/raid10: change read_balance to return an rdev
md/raid10: prepare data structures for handling replacement.
md/raid5: Mark device want_replacement when we see a write error.
md/raid5: If there is a spare and a want_replacement device, start replacement.
md/raid5: recognise replacements when assembling array.
...
Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export
kill_bdev as well, so brd doesn't have to open code it. Reduce
buffer_head.h requirement accordingly.
Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving. The small comment replacing it says enough.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Now that WantReplacement drives are replaced cleanly, mark a drive
as want_replacement when we see a write error. It might get failed soon so
the WantReplacement flag is irrelevant, but if the write error is recorded
in the bad block log, we still want to activate any spare that might
be available.
Signed-off-by: NeilBrown <neilb@suse.de>
When attempting to add a spare to a RAID1 array, also consider
adding it as a replacement for a want_replacement device.
Signed-off-by: NeilBrown <neilb@suse.de>
If a Replacement is seen, file it as such.
If we see two replacements (or two normal devices) for the one slot,
abort.
Signed-off-by: NeilBrown <neilb@suse.de>
When recovery completes ->spare_active is called.
This checks if the replacement is ready and if so it fails
the original.
Signed-off-by: NeilBrown <neilb@suse.de>
In RAID1, a replacement is much like a normal device, so we just
double the size of the relevant arrays and look at all possible
devices for reads and writes.
This means that the array looks like it is now double the size in some
way - we need to be careful about that.
In particular, we checking if the array is still degraded while
creating a recovery request we need to only consider the first 'half'
- i.e. the real (non-replacement) devices.
Signed-off-by: NeilBrown <neilb@suse.de>
In general mddev->raid_disks can change unexpectedly while
conf->raid_disks will only change in a very controlled way. So change
some uses of one to the other.
The use of mddev->raid_disks will not cause actually problems but
this way is more consistent and safer in the long term.
Signed-off-by: NeilBrown <neilb@suse.de>
When attempting to add a spare to a RAID10 array, also consider
adding it as a replacement for a want_replacement device.
Signed-off-by: NeilBrown <neilb@suse.de>
If a Replacement is seen, file it as such.
If we see two replacements (or two normal devices) for the one slot,
abort.
Signed-off-by: NeilBrown <neilb@suse.de>
When recovery finish and spare_active is called, check for a
replace that might have just become fully synced and mark it
as such, marking the original as failed.
Then when the original is removed, move the replacement into
its position.
This means that 'replacement' and spontaneously become NULL in some
situations. Make sure we check for those.
It also means that 'rdev' and 'replacement' could appear to be
identical - check for that too.
Signed-off-by: NeilBrown <neilb@suse.de>
If there is a replacement device, then recover to it,
reading from any drives - maybe the one being replaced, maybe not.
Signed-off-by: NeilBrown <neilb@suse.de>
If we need to resync an array which has replacement devices,
we always write any block checked to every replacement.
If the resync was bitmap-based resync we will then complete the
replacement normally.
If it was a full resync, we mark the replacements as fully recovered
when the resync finishes so no further recovery is needed.
Signed-off-by: NeilBrown <neilb@suse.de>
When writing, we need to submit two writes, one to the original,
and one to the replacements - if there is a replacement.
If the write to the replacement results in a write error we just
fail the device. We only try to record write errors to the
original.
This only handles writing new data. Writing for resync/recovery
will come later.
Signed-off-by: NeilBrown <neilb@suse.de>
When reading (for array reads, not for recovery etc) we read from the
replacement device if it has recovered far enough.
This requires storing the chosen rdev in the 'r10_bio' so we can make
sure to drop the ref on the right device when the read finishes.
Signed-off-by: NeilBrown <neilb@suse.de>
It makes more sense to return an rdev than just an index as
read_balance() gets a reference to the rdev and so returning
the pointer make this more idiomatic.
This will be needed in a future patch when we might return
a 'replacement' rdev instead of the main rdev.
Signed-off-by: NeilBrown <neilb@suse.de>
Allow each slot in the RAID10 to have 2 devices, the want_replacement
and the replacement.
Also an r10bio to have 2 bios, and for resync/recovery allocate the
second bio if there are any replacement devices.
Signed-off-by: NeilBrown <neilb@suse.de>
Now that WantReplacement drives are replaced cleanly, mark a drive
as WantReplacement when we see a write error. It might get failed soon so
the WantReplacement flag is irrelevant, but if the write error is recorded
in the bad block log, we still want to activate any spare that might
be available.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When attempting to add a spare to a RAID[456] array, also consider
adding it as a replacement for a want_replacement device.
This requires that common md code attempt hot_add even when the array
is not formally degraded.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
If a Replacement is seen, file it as such.
If we see two replacements (or two normal devices) for the one slot,
abort.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When recovery completes - as reported by a call to ->spare_active,
we clear In_sync on the original and set it on the replacement.
Then when the original gets removed we move the replacement from
'replacement' to 'rdev'.
This could race with other code that is looking at these pointers,
so we use memory barriers and careful ordering to ensure that
a reader might see one device twice, but never no devices.
Then the readers guard against using both devices, which could
only happen when writing.
Signed-off-by: NeilBrown <neilb@suse.de>
During recovery we want to write to the replacement but not
the original. So we have two new flags
- R5_NeedReplace if this stripe has a replacement that needs to
be written at some stage
- R5_WantReplace if NeedReplace, and the data is available, and
a 'sync' has been requested on this stripe.
We also distinguish between 'sync and replace' which need to read
all other devices, and 'replace' which only needs to read the
devices being replaced.
Note that during resync we always write to any replacement device.
It might not need to be written to, but as we don't read to compare,
we have to write to be sure.
Signed-off-by: NeilBrown <neilb@suse.de>
When writing, we need to submit two writes, one to the original, and
one to the replacement - if there is a replacement.
If the write to the replacement results in a write error, we just fail
the device. We only try to record write errors to the original.
When writing for recovery, we shouldn't write to the original. This
will be addressed in a subsequent patch that generally addresses
recovery.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Enhance raid5_remove_disk to be able to remove ->replacement
as well as ->rdev.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
If a replacement device is present and has been recovered far enough,
then use it for reading into the stripe cache.
If we get an error we don't try to repair it, we just fail the device.
A replacement device that gives errors does not sound sensible.
This requires removing the setting of R5_ReadError when we get
a read error during a read that bypasses the cache. It was probably
a bad idea anyway as we don't know that every block in the read
caused an error, and it could cause ReadError to be set for the
replacement device, which is bad.
Signed-off-by: NeilBrown <neilb@suse.de>
We current initialise some fields of a bio when preparing a
stripe_head, and again just before submitting the request.
Remove the duplication by only setting the fields that lower level
devices don't touch in raid5_build_block, and only set the changeable
fields in ops_run_io.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Remove some #defines that are no longer used, and replace some
others with an enum.
And remove an unused field.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Just enhance data structures to record a second device per slot to be
used as a 'replacement' device, replacing the original.
We also have a second bio in each slot in each stripe_head. This will
only be used when writing to the array - we need to write to both the
original and the replacement at the same time, so will need two bios.
For now, only try using the replacement drive for aligned-reads.
In this case, we prefer the replacement if it has been recovered far
enough, otherwise use the original.
This includes a small enhancement. Previously we would only do
aligned reads if the target device was fully recovered. Now we also
do them if it has recovered far enough.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
hot-replace is a feature being added to md which will allow a
device to be replaced without removing it from the array first.
With hot-replace a spare can be activated and recovery can start while
the original device is still in place, thus allowing a transition from
an unreliable device to a reliable device without leaving the array
degraded during the transition. It can also be use when the original
device is still reliable but it not wanted for some reason.
This will eventually be supported in RAID4/5/6 and RAID10.
This patch adds a super-block flag to distinguish the replacement
device. If an old kernel sees this flag it will reject the device.
It also adds two per-device flags which are viewable and settable via
sysfs.
"want_replacement" can be set to request that a device be replaced.
"replacement" is set to show that this device is replacing another
device.
The "rd%d" links in /sys/block/mdXx/md only apply to the original
device, not the replacement. We currently don't make links for the
replacement - there doesn't seem to be a need.
Signed-off-by: NeilBrown <neilb@suse.de>
Soon an array will be able to have multiple devices with the
same raid_disk number (an original and a replacement). So removing
a device based on the number won't work. So pass the actual device
handle instead.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When setting the slot number on a device in an active array we
currently check that the number is not already in use.
We then call into the personality's hot_add_disk function
which performs the same test and returns the same error.
Thus the common test is not needed.
As we will shortly be changing some personalities to allow duplicates
in some cases (to support hot-replace), the common test will become
inconvenient.
So remove the common test.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
For each active region corresponding to a bit in the bitmap with have
a 14bit counter (and some flags).
This counts
number of active writes + bit in the on-disk bitmap + delay-needed.
The "delay-needed" is because we always want a delay before clearing a
bit. So the number here is normally number of active writes plus 2.
If there have been no writes for a while, we drop to 1.
If still no writes we clear the bit and drop to 0.
So for consistency, when setting bit from the on-disk bitmap or by
request from user-space it is best to set the counter to '2' to start
with.
In particular we might also set the NEEDED_MASK flag at this time, and
in all other cases NEEDED_MASK is only set when the counter is 2 or
more.
Signed-off-by: NeilBrown <neilb@suse.de>
When an array is being reshaped to change the number of devices,
the two halves can be differently degraded. e.g. one could be
missing a device and the other not.
So we need to be more careful about calculating the 'degraded'
attribute.
Instead of just inc/dec at appropriate times, perform a full
re-calculation examining both possible cases. This doesn't happen
often so it not a big cost, and we already have most of the code to
do it.
Signed-off-by: NeilBrown <neilb@suse.de>
We have a variable 'mddev' in this function, but repeatedly get the
same value by dereferencing bitmap->mddev.
There is room for simplification here...
Signed-off-by: NeilBrown <neilb@suse.de>
The info is already available in /proc/mdstat and /sys/block in
an accessible form so there is no point in putting a road-block in
the ioctl for information gathering.
Signed-off-by: NeilBrown <neilb@suse.de>
commit d0a4bb4927 introduced a
regression which is annoying but fairly harmless.
When writing to an array that is undergoing recovery (a spare
in being integrated into the array), writing to the array will
set bits in the bitmap, but they will not be cleared when the
write completes.
For bits covering areas that have not been recovered yet this is not a
problem as the recovery will clear the bits. However bits set in
already-recovered region will stay set and never be cleared.
This doesn't risk data integrity. The only negatives are:
- next time there is a crash, more resyncing than necessary will
be done.
- the bitmap doesn't look clean, which is confusing.
While an array is recovering we don't want to update the
'events_cleared' setting in the bitmap but we do still want to clear
bits that have very recently been set - providing they were written to
the recovering device.
So split those two needs - which previously both depended on 'success'
and always clear the bit of the write went to all devices.
Signed-off-by: NeilBrown <neilb@suse.de>
Before performing a recovery we try to remove any spares that
might not be working, then add any that might have become relevant.
Currently we abort on the first spare that cannot be added.
This is a false optimisation.
It is conceivable that - depending on rules in the personality - a
subsequent spare might be accepted.
Also the loop does other things like count the available spares and
reset the 'recovery_offset' value.
If we abort early these might not happen properly.
So remove the early abort.
In particular if you have an array what is undergoing recovery and
which has extra spares, then the recovery may not restart after as
reboot as the could of 'spares' might end up as zero.
Reported-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: NeilBrown <neilb@suse.de>
While reshaping a degraded array (as when reshaping a RAID0 by first
converting it to a degraded RAID4) we currently get confused about
which devices are in_sync. In most cases we get it right, but in the
region that is being reshaped we need to treat non-failed devices as
in-sync when we have the data but haven't actually written it out yet.
Reported-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
commit d70ed2e4fa
broke hot-add to a linear array.
After that commit, metadata if not written to devices until they
have been fully integrated into the array as determined by
saved_raid_disk. That patch arranged to clear that field after
a recovery completed.
However for linear arrays, there is no recovery - the integration is
instantaneous. So we need to explicitly clear the saved_raid_disk
field.
Signed-off-by: NeilBrown <neilb@suse.de>
Once a device is failed we really want to completely ignore it.
It should go away soon anyway.
In particular the presence of bad blocks on it should not cause us to
block as we won't be trying to write there anyway.
So as soon as we can check if a device is Faulty, do so and pretend
that it is already gone if it is Faulty.
Signed-off-by: NeilBrown <neilb@suse.de>
When we mark blocks as bad we need them to be acknowledged by the
metadata handler promptly.
For an in-kernel metadata handler that was already being done. But
for an external metadata handler we need to alert it of the change by
sending a notification through the sysfs file. This adds that
notification.
Signed-off-by: NeilBrown <neilb@suse.de>
Once a device is marked Faulty the badblocks - whether acknowledged or
not - become irrelevant. So they shouldn't cause the device to be
marked as Blocked.
Without this patch, a process might write "-blocked" to clear the
Blocked status, but while that will correctly fail the device, it
won't remove the apparent 'blocked' status.
Signed-off-by: NeilBrown <neilb@suse.de>
When we are accessing an mddev via sysfs we know that the
mddev cannot disappear because it has an embedded kobj which
is refcounted by sysfs.
And we also take the mddev_lock.
However this is not enough.
The final mddev_put could have been called and the
mddev_delayed_delete is waiting for sysfs to let go so it can destroy
the kobj and mddev.
In this state there are a lot of changes that should not be attempted.
To to guard against this we:
- initialise mddev->all_mddevs in on last put so the state can be
easily detected.
- in md_attr_show and md_attr_store, check ->all_mddevs under
all_mddevs_lock and mddev_get the mddev if it still appears to
be active.
This means that if we get to sysfs as the mddev is being deleted we
will get -EBUSY.
rdev_attr_store and rdev_attr_show are similar but already have
sufficient protection. They check that rdev->mddev still points to
mddev after taking mddev_lock. As this is cleared before delayed
removal which can only be requested under the mddev_lock, this
ensure the rdev and mddev are still alive.
Signed-off-by: NeilBrown <neilb@suse.de>
We like md devices to disappear when they really are not needed.
However it is not possible to tell from the current state whether it
is needed or not. We can only tell from recent history of changes.
In particular immediately after we create an md device it looks very
similar to immediately after we have finished with it.
So we always preserve a newly created md device until something
significant happens. This state is stored in 'hold_active'.
The normal case is to keep it until an ioctl happens, as that will
normally either activate it, or explicitly de-activate it. If it
doesn't then it was probably created by mistake and it is now time to
get rid of it.
We can also modify an array via sysfs (instead of via ioctl) and we
currently treat any change via sysfs like an ioctl as a sign that if
it now isn't more active, it should be destroyed.
However this is not appropriate as changes made via sysfs are more
gradual so we should look for a more definitive change.
So this patch only clears 'hold_active' from UNTIL_IOCTL to clear when
the array_state is changed via sysfs. Other changes via sysfs
are ignored.
Signed-off-by: NeilBrown <neilb@suse.de>
Page attributes are set using __set_bit rather than set_bit as
it normally called under a spinlock so the extra atomicity is not
needed.
However there are two places where we might set or clear page
attributes without holding the spinlock.
So add the spinlock in those cases.
This might be the cause of occasional reports that bits a aren't
getting clear properly - theory is that BITMAP_PAGE_PENDING gets lost
when BITMAP_PAGE_NEEDWRITE is set or cleared. This is an
inconvenience, not a threat to data safety.
Signed-off-by: NeilBrown <neilb@suse.de>
All updates that occur under STRIPE_ACTIVE should be globally visible
when STRIPE_ACTIVE clears. test_and_set_bit() implies a barrier, but
clear_bit() does not.
This is suitable for 3.1-stable.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
When the number of failed devices exceeds the allowed number
we must abort any active parity operations (checks or updates) as they
are no longer meaningful, and can lead to a BUG_ON in
handle_parity_checks6.
This bug was introduce by commit 6c0069c0ae
in 2.6.29.
Reported-by: Manish Katiyar <mkatiyar@gmail.com>
Tested-by: Manish Katiyar <mkatiyar@gmail.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
since it uses the module facilities.
Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For the files which are not themselves modular, we can change
them to include only the smaller export.h since all they are
doing is looking for EXPORT_SYMBOL.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include <linux/module.h>
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include <linux/module.h>
net: sch_generic remove redundant use of <linux/module.h>
net: inet_timewait_sock doesnt need <linux/module.h>
...
Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
* 'for-3.2/core' of git://git.kernel.dk/linux-block: (29 commits)
block: don't call blk_drain_queue() if elevator is not up
blk-throttle: use queue_is_locked() instead of lockdep_is_held()
blk-throttle: Take blkcg->lock while traversing blkcg->policy_list
blk-throttle: Free up policy node associated with deleted rule
block: warn if tag is greater than real_max_depth.
block: make gendisk hold a reference to its queue
blk-flush: move the queue kick into
blk-flush: fix invalid BUG_ON in blk_insert_flush
block: Remove the control of complete cpu from bio.
block: fix a typo in the blk-cgroup.h file
block: initialize the bounce pool if high memory may be added later
block: fix request_queue lifetime handling by making blk_queue_cleanup() properly shutdown
block: drop @tsk from attempt_plug_merge() and explain sync rules
block: make get_request[_wait]() fail if queue is dead
block: reorganize throtl_get_tg() and blk_throtl_bio()
block: reorganize queue draining
block: drop unnecessary blk_get/put_queue() in scsi_cmd_ioctl() and blk_get_tg()
block: pass around REQ_* flags instead of broken down booleans during request alloc/free
block: move blk_throtl prototypes to block/blk.h
block: fix genhd refcounting in blkio_policy_parse_and_set()
...
Fix up trivial conflicts due to "mddev_t" -> "struct mddev" conversion
and making the request functions be of type "void" instead of "int" in
- drivers/md/{faulty.c,linear.c,md.c,md.h,multipath.c,raid0.c,raid1.c,raid10.c,raid5.c}
- drivers/staging/zram/zram_drv.c
These files were getting the defines for EXPORT_SYMBOL because
device.h was including module.h. But we are going to put an
end to that. So add the proper export.h include now.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
A pending cleanup will mean that module.h won't be implicitly
everywhere anymore. Make sure the modular drivers in md dir
are actually calling out for <module.h> explicitly in advance.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
When devices in a RAID array are not in-sync, they are supposed to be
reported as such in the status output as an 'a' character, which means
"alive, but not in-sync". But when the entire array is rebuilt 'A' is
being used, which is incorrect. This patch corrects this to 'a'.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Allow userspace dm log implementations to register their log device so it
is no longer missing from the list of device dependencies.
When device mapper targets use a device they normally call dm_get_device
which includes it in the device list returned to userspace applications
such as LVM through the DM_TABLE_DEPS ioctl. Userspace log devices
don't use dm_get_device as userspace opens them so they are missing from
the list of dependencies.
This patch extends the DM_ULOG_CTR operation to allow userspace to
respond with the name of the log device (if appropriate) to be
registered via 'dm_get_device'. DM_ULOG_REQUEST_VERSION is incremented.
This is backwards compatible. If the kernel and userspace log server
have both been updated, the new information will be passed down to the
kernel and the device will be registered. If the kernel is new, but
the log server is old, the log server will not pass down any device
information and the kernel will simply bypass the device registration
as before. If the kernel is old but the log server is new, the log
server will see the old version number and not pass the device info.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Fix comments: clustered-disk needs a hyphen not an underscore.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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>
The persistent-data library offers a re-usable framework for the storage
and management of on-disk metadata in device-mapper targets.
It's used by the thin-provisioning target in the next patch and in an
upcoming hierarchical storage target.
For further information, please read
Documentation/device-mapper/persistent-data.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>
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>
Introduce DM_TARGET_IMMUTABLE to indicate that the target type cannot be mixed
with any other target type, and once loaded into a device, it cannot be
replaced with a table containing a different type.
The thin provisioning pool device will use this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add a target feature flag DM_TARGET_ALWAYS_WRITEABLE to indicate that a target
does not support read-only mode.
The initial implementation of the thin provisioning target uses this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Introduce the concept of a singleton table which contains exactly one target.
If a target type sets the DM_TARGET_SINGLETON feature bit device-mapper
will ensure that any table that includes that target contains no others.
The thin provisioning pool target uses this.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch introduces dm_kcopyd_zero() to make it easy to use
kcopyd to write zeros into the requested areas instead
instead of copying. It is implemented by passing a NULL
copying source to dm_kcopyd_copy().
The forthcoming thin provisioning target uses this.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Since set_current_state() contains a memory barrier in it,
an additional barrier isn't needed.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
printk_ratelimit() shares global ratelimiting state with all
other subsystems, so its usage is discouraged. Instead,
define and use dm's local state.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Allow QUEUE_FLAG_NONROT to propagate up the device stack if all
underlying devices are non-rotational. Tools like ureadahead will
schedule IOs differently based on the rotational flag.
With this patch, I see boot time go from 7.75 s to 7.46 s on my device.
Suggested-by: J. Richard Barnette <jrbarnette@chromium.org>
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: dm-devel@redhat.com
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This is a fairly serious bug in RAID10.
When a RAID10 array is degraded and a hot-spare is activated, the
spare does not take up the empty slot, but rather replaces the first
working device.
This is likely to make the array non-functional. It would normally
be possible to recover the data, but that would need care and is not
guaranteed.
This bug was introduced in commit
2bb77736ae
which first appeared in 3.1.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
In 3.0 we changed the way recovery_disabled was handle so that instead
of testing against zero, we test an mddev-> value against a conf->
value.
Two problems:
1/ one place in raid1 was missed and still sets to '1'.
2/ We didn't explicitly set the conf-> value at array creation
time.
It defaulted to '0' just like the mddev value does so they
could appear equal and thus disable recovery.
This did not affect normal 'md' as it calls bind_rdev_to_array
which changes the mddev value. However the dmraid interface
doesn't call this and so doesn't change ->recovery_disabled; so at
array start all recovery is incorrectly disabled.
So initialise the 'conf' value to one less that the mddev value, so
the will only be the same when explicitly set that way.
Reported-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This bug was introduced in 415e72d034
which was in 2.6.36.
There is a small window of time between when a device fails and when
it is removed from the array. During this time we might still read
from it, but we won't write to it - so it is possible that we could
read stale data.
We didn't need the test of 'Faulty' before because the test on
In_sync is sufficient. Since we started allowing reads from the early
part of non-In_sync devices we need a test on Faulty too.
This is suitable for any kernel from 2.6.36 onwards, though the patch
might need a bit of tweaking in 3.0 and earlier.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
bio originally has the functionality to set the complete cpu, but
it is broken.
Chirstoph said that "This code is unused, and from the all the
discussions lately pretty obviously broken. The only thing keeping
it serves is creating more confusion and possibly more bugs."
And Jens replied with "We can kill bio_set_completion_cpu(). I'm fine
with leaving cpu control to the request based drivers, they are the
only ones that can toggle the setting anyway".
So this patch tries to remove all the work of controling complete cpu
from a bio.
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix memory leak introduced by commit a6e50b409d
(dm snapshot: skip reading origin when overwriting complete chunk).
When allocating a set of jobs from kc->job_pool, job->master_job must be
set (to point to itself) so that the mempool item gets freed when the
master_job completes.
master_job was introduced by commit c6ea41fbbe
(dm kcopyd: preallocate sub jobs to avoid deadlock)
Reported-by: Michael Leun <ml@newton.leun.net>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
If an incremental recovery was interrupted, a subsequent
re-add will result in a full recovery, even though an
incremental should be possible (seen with raid1).
Solve this problem by not updating the superblock on the
recovering device until array is not degraded any longer.
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrei Warkentin <andreiw@vmware.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When we add a device to an active array it can be meaningful to set
the 'insync' flag. This indicates that the device is in-sync with the
array except for locations recorded in the bitmap.
A bitmap-based recovery can then bring it completely in-sync.
Internally we move that flag to 'saved_raid_disk' but forgot to clear
In_sync like we do in add_new_disk.
So clear In_sync after moving its value to saved_raid_disk.
Reported-by: Andrei Warkentin <andreiw@vmware.com>
Signed-off-by: NeilBrown <neilb@suse.de>
RAID1 and RAID10 handle write requests by queuing them for handling by
a separate thread. This is because when a write-intent-bitmap is
active we might need to update the bitmap first, so it is good to
queue a lot of writes, then do one big bitmap update for them all.
However writeback request devices to appear to be congested after a
while so it can make some guesstimate of throughput. The infinite
queue defeats that (note that RAID5 has already has a finite queue so
it doesn't suffer from this problem).
So impose a limit on the number of pending write requests. By default
it is 1024 which seems to be generally suitable. Make it configurable
via module option just in case someone finds a regression.
Signed-off-by: NeilBrown <neilb@suse.de>
The typedefs are just annoying. 'mdk' probably refers to 'md_k.h'
which used to be an include file that defined this thing.
Signed-off-by: NeilBrown <neilb@suse.de>
When md assembles a RAID0 array it prints out lots of info which
is really just for debugging, so convert that to pr_debug.
It also prints out the resulting configuration which could be
interesting, so keep that as 'printk' but tidy it up a bit.
Signed-off-by: NeilBrown <neilb@suse.de>
