We've noticed severe lasting performance degradation of our raid
arrays when we have drives that yield large amounts of media errors.
The raid10 module will queue each failed read for retry, and also
will attempt call fix_read_error() to perform the read recovery.
Read recovery is performed while the array is frozen, so repeated
recovery attempts can degrade the performance of the array for
extended periods of time.
With this patch I propose adding a per md device max number of
corrected read attempts. Each rdev will maintain a count of
read correction attempts in the rdev->read_errors field (not
used currently for raid10). When we enter fix_read_error()
we'll check to see when the last read error occurred, and
divide the read error count by 2 for every hour since the
last read error. If at that point our read error count
exceeds the read error threshold, we'll fail the raid device.
In addition in this patch I add sysfs nodes (get/set) for
the per md max_read_errors attribute, the rdev->read_errors
attribute, and added some printk's to indicate when
fix_read_error fails to repair an rdev.
For testing I used debugfs->fail_make_request to inject
IO errors to the rdev while doing IO to the raid array.
Signed-off-by: Robert Becker <Rob.Becker@riverbed.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When we get a read error on a device in a RAID10, and attempting to
repair the error fails, print more useful messages about why it
failed.
Signed-off-by: Robert Becker <Rob.Becker@riverbed.com>
Signed-off-by: NeilBrown <neilb@suse.de>
There is a sysfs file which allows bits in the write-intent
bitmap to be explicit set - indicating that the block is thought
to be 'dirty'.
When this happens we should really set recovery_cp backwards
to include the block to reflect this dirtiness.
In particular, a 'resync' process will refuse to start if
recovery_cp is beyond the end of the array, so this is needed
to allow a resync to be triggered.
Signed-off-by: NeilBrown <neilb@suse.de>
In this case, the metadata needs to not be in the same
sector as the bitmap.
md will not read/write any bitmap metadata. Config must be
done via sysfs and when a recovery makes the array non-degraded
again, writing 'true' to 'bitmap/can_clear' will allow bits in
the bitmap to be cleared again.
Signed-off-by: NeilBrown <neilb@suse.de>
Setting daemon_lastrun really has nothing to do with reading
the bitmap superblock, it just happens to be needed at the same time.
bitmap_read_sb is about to become options, so move that code out
to after the call to bitmap_read_sb.
Signed-off-by: NeilBrown <neilb@suse.de>
A new attribute directory 'bitmap' in 'md' is created which
contains files for configuring the bitmap.
'location' identifies where the bitmap is, either 'none',
or 'file' or 'sector offset from metadata'.
Writing 'location' can create or remove a bitmap.
Adding a 'file' bitmap this way is not yet supported.
'chunksize' and 'time_base' must be set before 'location'
can be set.
'chunksize' can be set before creating a bitmap, but is
currently always over-ridden by the bitmap superblock.
'time_base' and 'backlog' can be updated at any time.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Andre Noll <maan@systemlinux.org>
safe_delay_store can parse fixed point numbers (for fractions
of a second). We will want to do that for another sysfs
file soon, so factor out the code.
Signed-off-by: NeilBrown <neilb@suse.de>
For md arrays were metadata is managed externally, the kernel does not
know about a superblock so the superblock offset is 0.
If we want to have a write-intent-bitmap near the end of the
devices of such an array, we should support sector_t sized offset.
We need offset be possibly negative for when the bitmap is before
the metadata, so use loff_t instead.
Also add sanity check that bitmap does not overlap with data.
Signed-off-by: NeilBrown <neilb@suse.de>
As bitmap_create and bitmap_destroy already set thread->timeout
as appropriate, there is no need to do it in raid10_quiesce.
There is a possible need to wake the thread after the timeout
has been set low, but it is better to do that where the timeout
is actually set low, in bitmap_create.
Signed-off-by: NeilBrown <neilb@suse.de>
... and into bitmap_info. These are all configuration parameters
that need to be set before the bitmap is created.
Signed-off-by: NeilBrown <neilb@suse.de>
In preparation for making bitmap fields configurable via sysfs,
start tidying up by making a single structure to contain the
configuration fields.
Signed-off-by: NeilBrown <neilb@suse.de>
This will allow us to stop writeout to portions of the array
while they are resynced by someone else - e.g. another node in
a cluster.
Signed-off-by: NeilBrown <neilb@suse.de>
The post-barrier-flush is sent by md as soon as make_request on the
barrier write completes. For raid5, the data might not be in the
per-device queues yet. So for barrier requests, wait for any
pre-reading to be done so that the request will be in the per-device
queues.
We use the 'preread_active' count to check that nothing is still in
the preread phase, and delay the decrement of this count until after
write requests have been submitted to the underlying devices.
Signed-off-by: NeilBrown <neilb@suse.de>
Previously barriers were only supported on RAID1. This is because
other levels requires synchronisation across all devices and so needed
a different approach.
Here is that approach.
When a barrier arrives, we send a zero-length barrier to every active
device. When that completes - and if the original request was not
empty - we submit the barrier request itself (with the barrier flag
cleared) and then submit a fresh load of zero length barriers.
The barrier request itself is asynchronous, but any subsequent
request will block until the barrier completes.
The reason for clearing the barrier flag is that a barrier request is
allowed to fail. If we pass a non-empty barrier through a striping
raid level it is conceivable that part of it could succeed and part
could fail. That would be way too hard to deal with.
So if the first run of zero length barriers succeed, we assume all is
sufficiently well that we send the request and ignore errors in the
second run of barriers.
RAID5 needs extra care as write requests may not have been submitted
to the underlying devices yet. So we flush the stripe cache before
proceeding with the barrier.
Note that the second set of zero-length barriers are submitted
immediately after the original request is submitted. Thus when
a personality finds mddev->barrier to be set during make_request,
it should not return from make_request until the corresponding
per-device request(s) have been queued.
That will be done in later patches.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Andre Noll <maan@systemlinux.org>
If a resync/recovery/check/repair is interrupted for some reason, it
can be useful to know exactly where it got up to.
So in that case, do not clear curr_resync_completed.
Initialise it when starting a resync/recovery/... instead.
Signed-off-by: NeilBrown <neilb@suse.de>
When a 'check' or 'repair' finished we should clear resync_min
so that a future check/repair will cover the whole array (by default).
However if it is interrupted, we should update resync_min to
where we got up to, so that when the check/repair continues it
just does the remainder of the array.
Signed-off-by: NeilBrown <neilb@suse.de>
A write intent bitmap can be removed from an array while the
array is active.
When this happens, all IO is suspended and flushed before the
bitmap is removed.
However it is possible that bitmap_daemon_work is still running to
clear old bits from the bitmap. If it is, it can dereference the
bitmap after it has been freed.
So introduce a new mutex to protect bitmap_daemon_work and get it
before destroying a bitmap.
This is suitable for any current -stable kernel.
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
If the snapshot we are merging became invalid (e.g. it ran out of
space) redirect all I/O directly to the origin device.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Set 'merge_failed' flag if a snapshot fails to merge. Update
snapshot_status() to report "Merge failed" if 'merge_failed' is set.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
s->store->type->prepare_merge returns the number of chunks that can be
copied linearly working backwards from the returned chunk number.
For example, if it returns 3 chunks with old_chunk == 10 and new_chunk
== 20, then chunk 20 can be copied to 10, chunk 19 to 9 and 18 to 8.
Until now kcopyd only copied one chunk at a time. This patch now copies
the full set at once.
Consequently, snapshot_merge_process() needs to delay the merging of all
chunks if any have writes in progress, not just the first chunk in the
region that is to be merged.
snapshot-merge's performance is now comparable to the original
snapshot-origin target.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
When there is one merging snapshot and other non-merging snapshots,
snapshot_merge_process() must make exceptions in the non-merging
snapshots.
Use a sequence count to resolve the race between I/O to chunks that are
about to be merged. The count increases each time an exception
reallocation finishes. Use wait_event() to wait until the count
changes.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Track writes to chunks that are currently being merged and delay merging
a chunk until all writes to that chunk finish.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
While a set of chunks is being merged, any overlapping writes need to be
queued.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Merging is started when origin is resumed and it is stopped when
origin is suspended or when the merging snapshot is destroyed or
errors are detected.
Merging is not yet interlocked with writes: this will be handled in
subsequent patches.
The code relies on callbacks from a private kcopyd thread.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Merging more than one snapshot is not supported, so prevent
this happening.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Sets num_flush_requests=2 to support flushing both the origin and cow
devices used by the snapshot-merge target.
Also, snapshot_ctr() now gets the origin device using FMODE_WRITE if the
target is snapshot-merge (which writes to the origin device).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The snapshot-merge target should not allocate new exceptions because the
intent is to merge all of its exceptions as quickly and safely as
possible.
This patch introduces the snapshot-merge mapping function and updates
__origin_write() so that it doesn't allocate exceptions on any snapshots
that are being merged.
If a write request to a merging snapshot device is to be dispatched
directly to the origin (because the chunk is not remapped or was already
merged), snapshot_merge_map() must make exceptions in other snapshots so
calls do_origin().
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
To track the completion of exceptions relating to the same location on
the device, the current code selects one exception as primary_pe, links
the other exceptions to it and uses reference counting to wait until all
the reallocations are complete.
It is considered too complicated to extend this code to handle the new
snapshot-merge target, where sets of non-overlapping chunks would also
need to become linked.
Instead, a simpler (but less efficient) approach is taken. Bios are
linked to one exception. When it completes, bios are simply retried,
and if other related exceptions are still outstanding, they'll get
queued again to wait for another one.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The snapshot-merge target allows a snapshot to be merged back into the
snapshot's origin device.
One anticipated use of snapshot merging is the rollback of filesystems
to back out problematic system upgrades.
This patch adds snapshot-merge target management to both
dm_snapshot_init() and dm_snapshot_exit(). As an initial place-holder,
snapshot-merge is identical to the snapshot target. Documentation is
provided.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add functions that decide how many consecutive chunks of snapshot to
merge back into the origin next and to update the metadata afterwards.
prepare_merge provides a pointer to the most recent still-to-be-merged
chunk and returns how many previous ones are consecutive and can be
processed together.
commit_merge removes the nr_merged most-recent chunks permanently from
the exception store. The number must not exceed that returned by
prepare_merge.
Introduce NUM_SNAPSHOT_HDR_CHUNKS to show where the snapshot header
chunk is accounted for.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Move the __chunk_is_tracked() loop into a separate function as we will
also need to call it from the write path in the rare case of conflicting
writes to the same chunk.
Originally introduced in commit a8d41b59f3
("dm snapshot: fix race during exception creation").
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
To support the merging of snapshots back into their origin we need
to trigger exceptions in other snapshots not being merged without
any incoming bio on the origin device. The bio parameter to
__origin_write() becomes optional and the sector needs supplying
separately.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch rejects messages that can generate I/O while the device
itself is suspended.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch adds the exported dm_suspended() function so that targets
can check whether or not they are suspended.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch renames dm_suspended() to dm_suspended_md() and
keeps it internal to dm.
No functional change.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch moves DMF_SUSPENDED flag set before postsuspend.
No one should care about the ordering, because the flag set and
the postsuspend are protected by a single lock, md->suspend_lock,
and all strict flag-checkers take the lock.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The default plain IV is 32-bit only.
This plain64 IV provides a compatible mode for encrypted devices bigger
than 4TB.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Permit in-use snapshot exception data to be 'handed over' from one
snapshot instance to another. This is a pre-requisite for patches
that allow the changes made in a snapshot device to be merged back into
its origin device and also allows device resizing.
The basic call sequence is:
dmsetup load new_snapshot (referencing the existing in-use cow device)
- the ctr code detects that the cow is already in use and allows the
two snapshot target instances to be linked together
dmsetup suspend original_snapshot
dmsetup resume new_snapshot
- the new_snapshot becomes live, and if anything now tries to access
the original one it will receive -EIO
dmsetup remove original_snapshot
(There can only be two snapshot targets referencing the same cow device
simultaneously.)
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
When swapping a new table into place, retain the old table until
its replacement is in place.
An old check for an empty table is removed because this is enforced
in populate_table().
__unbind() becomes redundant when followed by __bind().
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
When replacing a mapped device's table during a 'resume', delay the
destruction of the old table until the new one is successfully in place.
This will make it easier for a later patch to transfer internal state
information from the old table to the new one (something we do not currently
support) while giving us more options for reversion if a later part
of the operation fails.
Devices are always in the suspended state during dm_swap_table().
This patch reinforces the requirement that all I/O must have been
flushed from the table targets while in this state (including any in
workqueues). In the case of 'noflush' suspending, unprocessed
I/O should have been 'pushed back' to the dm core prior to this point,
for resubmission after the new table is in place.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add the flag DM_QUERY_INACTIVE_TABLE_FLAG to the ioctls to return
infomation about the loaded-but-not-yet-active table instead of the live
table. Prior to this patch it was impossible to obtain this information
until the device had been 'resumed'.
Userspace dmsetup and libdevmapper support the flag as of version 1.02.40.
e.g. dmsetup info --inactive vg1-lv1
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Accept empty barriers in dm-io.
dm-io will process empty write barrier requests just like the other
read/write requests.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reject messages that can generate I/O while the device itself
is suspended.
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add a mutex to allow possible creators of new work to synchronize with
flushing work queues.
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Once we begin deleting a device, prevent any further messages being sent
to targets of its table (to avoid races).
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add dm_deleting_md to check whether or not a given mapped
device is currently being deleted.
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch stops the remaining dm-mpath activity during the suspend
sequence by flushing workqueues in postsuspend function.
The current dm-mpath target may not be quiet even after suspend completes
because some workqueues (e.g. device_handler's work, event handling)
are not flushed during the suspend sequence, even though suspended
devices/targets are supposed to be quiet in this state.
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>
This patch adds barrier support for request-based dm.
CORE DESIGN
The design is basically same as bio-based dm, which emulates barrier
by mapping empty barrier bios before/after a barrier I/O.
But request-based dm has been using struct request_queue for I/O
queueing, so the block-layer's barrier mechanism can be used.
o Summary of the block-layer's behavior (which is depended by dm-core)
Request-based dm uses QUEUE_ORDERED_DRAIN_FLUSH ordered mode for
I/O barrier. It means that when an I/O requiring barrier is found
in the request_queue, the block-layer makes pre-flush request and
post-flush request just before and just after the I/O respectively.
After the ordered sequence starts, the block-layer waits for all
in-flight I/Os to complete, then gives drivers the pre-flush request,
the barrier I/O and the post-flush request one by one.
It means that the request_queue is stopped automatically by
the block-layer until drivers complete each sequence.
o dm-core
For the barrier I/O, treats it as a normal I/O, so no additional
code is needed.
For the pre/post-flush request, flushes caches by the followings:
1. Make the number of empty barrier requests required by target's
num_flush_requests, and map them (dm_rq_barrier()).
2. Waits for the mapped barriers to complete (dm_rq_barrier()).
If error has occurred, save the error value to md->barrier_error
(dm_end_request()).
(*) Basically, the first reported error is taken.
But -EOPNOTSUPP supersedes any error and DM_ENDIO_REQUEUE
follows.
3. Requeue the pre/post-flush request if the error value is
DM_ENDIO_REQUEUE. Otherwise, completes with the error value
(dm_rq_barrier_work()).
The pre/post-flush work above is done in the kernel thread (kdmflush)
context, since memory allocation which might sleep is needed in
dm_rq_barrier() but sleep is not allowed in dm_request_fn(), which is
an irq-disabled context.
Also, clones of the pre/post-flush request share an original, so
such clones can't be completed using the softirq context.
Instead, complete them in the context of underlying device drivers.
It should be safe since there is no I/O dispatching during
the completion of such clones.
For suspend, the workqueue of kdmflush needs to be flushed after
the request_queue has been stopped. Otherwise, the next flush work
can be kicked even after the suspend completes.
TARGET INTERFACE
No new interface is added.
Just use the existing num_flush_requests in struct target_type
as same as bio-based dm.
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>
This patch moves dm_end_request() to make the next patch more readable.
No functional change.
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>
This patch factors out the clone completion code, dm_done(),
from dm_softirq_done() in preparation for a subsequent patch.
No functional change.
dm_done() will be used in barrier completion, which can't use and
doesn't need softirq. The softirq_done callback needs to get a clone
from an original request but it can't in the case of barrier, where
an original request is shared by multiple clones. On the other hand,
the completion of barrier clones doesn't involve re-submitting requests,
which was the primary reason of the need for softirq.
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>
This patch changes the counter for the number of in_flight I/Os
to md->pending from q->in_flight in preparation for a later patch.
No functional change.
Request-based dm used q->in_flight to count the number of in-flight
clones assuming the counter is always incremented for an in-flight
original request and original:clone is 1:1 relationship.
However, it this no longer true for barrier requests.
So use md->pending to count the number of in-flight clones.
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>
The semantics of bio-based dm were changed recently in the case of
suspend with "--nolockfs" but without "--noflush".
Before 2.6.30, I/Os submitted before the suspend invocation were always
flushed. From 2.6.30 onwards, I/Os submitted before the suspend
invocation might not be flushed. (For details, see
http://marc.info/?t=123994433400003&r=1&w=2)
This patch brings the behaviour of request-based dm into line with
bio-based dm, simplifying the code and preparing for a subsequent patch
that will wait for all in_flight I/Os to complete without stopping
request_queue and use dm_wait_for_completion() for it.
This change in semantics simplifies the suspend code as follows:
o Suspend is implemented as stopping request_queue
in request-based dm, and all I/Os are queued in the request_queue
even after suspend is invoked.
o In the old semantics, we had to track whether I/Os were
queued before or after the suspend invocation, so a special
barrier-like request called 'suspend marker' was introduced.
o With the new semantics, we don't need to flush any I/O
so we can remove the marker and the code related to the marker
handling and I/O flushing.
After removing this codes, the suspend sequence is now:
1. Flush all I/Os by lock_fs() if needed.
2. Stop dispatching any I/O by stopping the request_queue.
3. Wait for all in-flight I/Os to be completed or requeued.
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>
This patch factors out the request cloning code in dm_prep_fn()
as clone_rq(). No functional change.
This patch is a preparation for a later patch in this series which needs to
make clones from an original barrier request.
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>
This patch adds the gfp_mask argument to alloc_rq_tio().
No functional change.
This patch is a preparation for a later patch in this series which needs to
allocate tio (for barrier I/O) with different allocation flag (GFP_NOIO) from
the one in the normal I/O code path.
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>
This patch changes the argument of map_request() to clone request
from original request. No functional change.
This patch is a preparation for PATCH 9, which needs to use
map_request() for clones sharing an original barrier request.
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>
This patch adds md_in_flight() to get the number of in_flight I/Os.
No functional change.
This patch is a preparation for a later patch in this series, which
changes I/O counter to md->pending from q->in_flight in request-based dm.
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>
dm-kcopyd: accept zero-size jobs
This patch changes dm-kcopyd so that it accepts zero-size jobs and completes
them immediatelly via its completion thread.
It is needed for multisnapshots snapshot resizing. When we are writing to
a chunk beyond origin end, no copying is done. To simplify the code, we submit
an empty request to kcopyd and let kcopyd complete it. If we didn't submit
a request to kcopyd and called the completion routine immediatelly, it would
violate the principle that completion is called only from one thread and
it would need additional locking.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Keep track of whether or not the device is suspended within the snapshot
target module, the same as we do in dm-raid1.
We will use this later to enforce the correct sequence of ioctls to
transfer the in-core exceptions from a snapshot target instance in
one table to a replacement one capable of merging them back
into the origin.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Store the reference to the snapshot cow device in the core snapshot
code instead of each exception store. It can be accessed through the
new function dm_snap_cow(). Exception stores should each now maintain a
reference to their parent snapshot struct.
This is cleaner and makes part of the forthcoming snapshot merge code simpler.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Add number of sectors used by metadata to the end of the snapshot's status
line.
Renamed dm_exception_store_type's 'fraction_full' to 'usage'. Renamed
arguments to be clearer about what is being returned. Also added
'metadata_sectors'.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Rename exception functions. Preparing to pull them out of
dm-snap.c for broader use.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Rename exception_table for broader use outside dm-snap.c
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The exception structure is not necessarily just a snapshot
element (especially after we pull it out of dm-snap.c).
Renaming appropriately.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Consolidate the insert_*exception functions. 'insert_completed_exception'
already contains all the logic to handle 'insert_exception' (via
check for a hash_shift of 0), so remove redundant function.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The origin needs to find minimum chunksize of all snapshots. This logic is
moved to a separate function because it will be used at another place in
the snapshot merge patches.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Removed unnecessary 'and' masking: The right shift discards the lower
bits so there is no need to clear them.
(A later patch needs this change to support a 32-bit chunk_mask.)
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Minor code touch-up. We don't need the 'else'.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
strlcpy() will always null terminate the string.
The code should already guarantee this as the last bytes are already
NULs and the string lengths were restricted before being stored in
hc. Removing the '-1' becomes necessary so strlcpy() doesn't
lose the last character of a maximum-length string.
- agk
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Hold all write bios when leg fails and errors are handled
When using a userspace daemon such as dmeventd to handle errors, we must
delay completing bios until it has done its job.
This patch prevents the following race:
- primary leg fails
- write "1" fail, the write is held, secondary leg is set default
- write "2" goes straight to the secondary leg
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Takahiro Yasui <tyasui@redhat.com>
Tested-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Hold all write bios when errors are handled.
Previously the failures list was used only when handling errors with
a userspace daemon such as dmeventd. Now, it is always used for all bios.
The regions where some writes failed must be marked as nosync. This can only
be done in process context (i.e. in raid1 workqueue), not in the
write_callback function.
Previously the write would succeed if writing to at least one leg
succeeded. This is wrong because data from the failed leg may be
replicated to the correct leg. Now, if using a userspace daemon, the
write with some failures will be held until the daemon has done its job
and reconfigured the array. If not using a daemon, the write still
succeeds if at least one leg succeeds. This is bad, but it is consistent
with current behavior.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Takahiro Yasui <tyasui@redhat.com>
Tested-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Move bio completion out of dm_rh_mark_nosync in preparation for the
next patch.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Takahiro Yasui <tyasui@redhat.com>
Tested-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Move the logic to get a valid mirror leg into a function for re-use
in a later patch.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Takahiro Yasui <tyasui@redhat.com>
Tested-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Use the hold framework in do_failures.
This patch doesn't change the bio processing logic, it just simplifies
failure handling and avoids periodically polling the failures list.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Takahiro Yasui <tyasui@redhat.com>
Tested-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add framework to delay bios until a suspend and then resubmit them with
either DM_ENDIO_REQUEUE (if the suspend was noflush) or complete them
with -EIO. I/O barrier support will use this.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Takahiro Yasui <tyasui@redhat.com>
Tested-by: Takahiro Yasui <tyasui@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Report flush errors as 'F' instead of 'D' for log and mirror devices.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Implement flush callee. It uses dm_io to send zero-size barrier synchronously
and concurrently to all the mirror legs.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Call the flush callback from the log.
If flush failed, we have no alternative but to mark the whole log as dirty.
Also we set the variable flush_failed to prevent any bits ever being marked as
clean again.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Introduce a callback pointer from the log to dm-raid1 layer.
Before some region is set as "in-sync", we need to flush hardware cache on
all the disks. But the log module doesn't have access to the mirror_set
structure. So it will use this callback.
So far the callback is unused, it will be used in further patches.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Introduce "flush failed" variable. When a flush before clearing a bit
in the log fails, we don't know anything about which which regions are
in-sync and which not.
So we need to set all regions as not-in-sync and set the variable
"flush_failed" to prevent setting the in-sync bit in the future.
A target reload is the only way to get out of this situation.
The variable will be set in following patches.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Introduce flush_header and use it to flush the log device.
Note that we don't have to flush if all the regions transition
from "dirty" to "clean" state.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Split the variable "touched" into two, "touched_dirtied" and
"touched_cleaned", set when some region was dirtied or cleaned.
This will be used to optimize flushes.
After a transition from "dirty" to "clean" state we don't have flush hardware
cache on the log device. After a transition from "clean" to "dirty" the cache
must be flushed.
Before a transition from "clean" to "dirty" state we don't have to flush all
the raid legs. Before a transition from "dirty" to "clean" we must flush all
the legs to make sure that they are really in sync.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Flush support for dm-raid1.
When it receives an empty barrier, submit it to all the devices via dm-io.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove the hack where we allocate an extra bi_io_vec to store additional
private data. This hack prevents us from supporting barriers in
dm-raid1 without first making another little block layer change.
Instead of doing that, this patch eliminates the bi_io_vec abuse by
storing the region number directly in the low bits of bi_private.
We need to store two things for each bio, the pointer to the main io
structure and, if parallel writes were requested, an index indicating
which of these writes this bio belongs to. There can be at most
BITS_PER_LONG regions - 32 or 64.
The index (region number) was stored in the last (hidden) bio vector and
the pointer to struct io was stored in bi_private.
This patch now aligns "struct io" on BITS_PER_LONG bytes and stores the
region number in the low BITS_PER_LONG bits of bi_private.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Allocate "struct io" from a slab.
This patch changes dm-io, so that "struct io" is allocated from a slab cache.
It used to be allocated with kmalloc. Allocating from a slab will be needed
for the next patch, because it requires a special alignment of "struct io"
and kmalloc cannot meet this alignment.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The "wipe key" message is used to wipe the volume key from memory
temporarily, for example when suspending to RAM.
But the initialisation vector in ESSIV mode is calculated from the
hashed volume key, so the wipe message should wipe this IV key too and
reinitialise it when the volume key is reinstated.
This patch adds an IV wipe method called from a wipe message callback.
ESSIV is then reinitialised using the init function added by the
last patch.
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch separates the construction of IV from its initialisation.
(For ESSIV it is a hash calculation based on volume key.)
Constructor code now preallocates hash tfm and salt array
and saves it in a private IV structure.
The next patch requires this to reinitialise the wiped IV
without reallocating memory when resuming a suspended device.
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Use kzfree for salt deallocation because it is derived from the volume
key. Use a common error path in ESSIV constructor.
Required by a later patch which fixes the way key material is wiped
from memory.
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Define private structures for IV so it's easy to add further attributes
in a following patch which fixes the way key material is wiped from
memory. Also move ESSIV destructor and remove unnecessary 'status'
operation.
There are no functional changes in this patch.
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The "wipe key" message is used to wipe a volume key from memory
temporarily, for example when suspending to RAM.
There are two instances of the key in memory (inside crypto tfm)
but only one got wiped. This patch wipes them both.
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Under some special conditions the snapshot hash_size is calculated as zero.
This patch instead sets a minimum value of 64, the same as for the
pending exception table.
rounddown_pow_of_two(0) is an undefined operation (it expands to shift
by -1). init_exception_table with an argument of 0 would fail with -ENOMEM.
The way to trigger the problem is to create a snapshot with a chunk size
that is larger than the origin device.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Take snapshot lock only for STATUSTYPE_INFO, not STATUSTYPE_TABLE.
Commit 4c6fff445d
(dm-snapshot-lock-snapshot-while-supplying-status.patch)
introduced this use of the lock, but userspace applications using
libdevmapper have been found to request STATUSTYPE_TABLE while the device
is suspended and the lock is already held, leading to deadlock. Since
the lock is not necessary in this case, don't try to take it.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch just removes an unnecessary warning:
kobject: 'dm': does not have a release() function,
it is broken and must be fixed.
The kobject is embedded in mapped device struct, so
code does not need to release memory explicitly here.
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Error handling code following a kmalloc should free the allocated data.
Cc: stable@kernel.org
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Fix a reported deadlock if there are still unprocessed multipath events
on a device that is being removed.
_hash_lock is held during dev_remove while trying to send the
outstanding events. Sending the events requests the _hash_lock
again in dm_copy_name_and_uuid.
This patch introduces a separate lock around regions that modify the
link to the hash table (dm_set_mdptr) or the name or uuid so that
dm_copy_name_and_uuid no longer needs _hash_lock.
Additionally, dm_copy_name_and_uuid can only be called if md exists
so we can drop the dm_get() and dm_put() which can lead to a BUG()
while md is being freed.
The deadlock:
#0 [ffff8106298dfb48] schedule at ffffffff80063035
#1 [ffff8106298dfc20] __down_read at ffffffff8006475d
#2 [ffff8106298dfc60] dm_copy_name_and_uuid at ffffffff8824f740
#3 [ffff8106298dfc90] dm_send_uevents at ffffffff88252685
#4 [ffff8106298dfcd0] event_callback at ffffffff8824c678
#5 [ffff8106298dfd00] dm_table_event at ffffffff8824dd01
#6 [ffff8106298dfd10] __hash_remove at ffffffff882507ad
#7 [ffff8106298dfd30] dev_remove at ffffffff88250865
#8 [ffff8106298dfd60] ctl_ioctl at ffffffff88250d80
#9 [ffff8106298dfee0] do_ioctl at ffffffff800418c4
#10 [ffff8106298dff00] vfs_ioctl at ffffffff8002fab9
#11 [ffff8106298dff40] sys_ioctl at ffffffff8004bdaf
#12 [ffff8106298dff80] tracesys at ffffffff8005d28d (via system_call)
Cc: stable@kernel.org
Reported-by: guy keren <choo@actcom.co.il>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (222 commits)
[SCSI] zfcp: Remove flag ZFCP_STATUS_FSFREQ_TMFUNCNOTSUPP
[SCSI] zfcp: Activate fc4s attributes for zfcp in FC transport class
[SCSI] zfcp: Block scsi_eh thread for rport state BLOCKED
[SCSI] zfcp: Update FSF error reporting
[SCSI] zfcp: Improve ELS ADISC handling
[SCSI] zfcp: Simplify handling of ct and els requests
[SCSI] zfcp: Remove ZFCP_DID_MASK
[SCSI] zfcp: Move WKA port to zfcp FC code
[SCSI] zfcp: Use common code definitions for FC CT structs
[SCSI] zfcp: Use common code definitions for FC ELS structs
[SCSI] zfcp: Update FCP protocol related code
[SCSI] zfcp: Dont fail SCSI commands when transitioning to blocked fc_rport
[SCSI] zfcp: Assign scheduled work to driver queue
[SCSI] zfcp: Remove STATUS_COMMON_REMOVE flag as it is not required anymore
[SCSI] zfcp: Implement module unloading
[SCSI] zfcp: Merge trace code for fsf requests in one function
[SCSI] zfcp: Access ports and units with container_of in sysfs code
[SCSI] zfcp: Remove suspend callback
[SCSI] zfcp: Remove global config_mutex
[SCSI] zfcp: Replace local reference counting with common kref
...
* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6: (43 commits)
security/tomoyo: Remove now unnecessary handling of security_sysctl.
security/tomoyo: Add a special case to handle accesses through the internal proc mount.
sysctl: Drop & in front of every proc_handler.
sysctl: Remove CTL_NONE and CTL_UNNUMBERED
sysctl: kill dead ctl_handler definitions.
sysctl: Remove the last of the generic binary sysctl support
sysctl net: Remove unused binary sysctl code
sysctl security/tomoyo: Don't look at ctl_name
sysctl arm: Remove binary sysctl support
sysctl x86: Remove dead binary sysctl support
sysctl sh: Remove dead binary sysctl support
sysctl powerpc: Remove dead binary sysctl support
sysctl ia64: Remove dead binary sysctl support
sysctl s390: Remove dead sysctl binary support
sysctl frv: Remove dead binary sysctl support
sysctl mips/lasat: Remove dead binary sysctl support
sysctl drivers: Remove dead binary sysctl support
sysctl crypto: Remove dead binary sysctl support
sysctl security/keys: Remove dead binary sysctl support
sysctl kernel: Remove binary sysctl logic
...
Make scsi_dh_activate() function asynchronous, by taking in two additional
parameters, one is the callback function and the other is the data to call
the callback function with.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
commit 4706b349f was a forward port of a fix that was needed
for SLES10. But in fact it is not needed in mainline because
the earlier commit dd00a99e7a fixes the same problem in a
better way.
Further, this commit introduces a bug in the way it interacts with
the automatic read-error-correction. If, after a read error is
successfully corrected, the same disk is chosen to re-read - the
re-read won't be attempted but an error will be returned instead.
After reverting that commit, there is the possibility that a
read error on a read-only array (where read errors cannot
be corrected as that requires a write) will repeatedly read the same
device and continue to get an error.
So in the "Array is readonly" case, fail the drive immediately on
a read error.
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
For consistency drop & in front of every proc_handler. Explicity
taking the address is unnecessary and it prevents optimizations
like stubbing the proc_handlers to NULL.
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Resolve the conflict between v2.6.32-rc7 where dn_def_dev_handler
gets a small bug fix and the sysctl tree where I am removing all
sysctl strategy routines.
Normally is it not safe to allow a raid5 that is both dirty and
degraded to be assembled without explicit request from that admin, as
it can cause hidden data corruption.
This is because 'dirty' means that the parity cannot be trusted, and
'degraded' means that the parity needs to be used.
However, if the device that is missing contains only parity, then
there is no issue and assembly can continue.
This particularly applies when a RAID5 is being converted to a RAID6
and there is an unclean shutdown while the conversion is happening.
So check for whether the degraded space only contains parity, and
in that case, allow the assembly.
Signed-off-by: NeilBrown <neilb@suse.de>
When a reshape finds that it can add spare devices into the array,
those devices might already be 'in_sync' if they are beyond the old
size of the array, or they might not if they are within the array.
The first case happens when we change an N-drive RAID5 to an
N+1-drive RAID5.
The second happens when we convert an N-drive RAID5 to an
N+1-drive RAID6.
So set the flag more carefully.
Also, ->recovery_offset is only meaningful when the flag is clear,
so only set it in that case.
This change needs the preceding two to ensure that the non-in_sync
device doesn't get evicted from the array when it is stopped, in the
case where v0.90 metadata is used.
Signed-off-by: NeilBrown <neilb@suse.de>
This is a combination that didn't really make sense before.
However when a reshape is converting e.g. raid5 -> raid6, the extra
device is not fully in-sync, but is certainly active and contains
important data.
So allow that start to be meaningful and in particular get
the 'recovery_offset' value (which is needed for any non-in-sync
active device) from the reshape_position.
Signed-off-by: NeilBrown <neilb@suse.de>
Now that sys_sysctl is a wrapper around /proc/sys all of
the binary sysctl support elsewhere in the tree is
dead code.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Neil Brown <neilb@suse.de>
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>
Acked-by: Clemens Ladisch <clemens@ladisch.de> for drivers/char/hpet.c
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Each device has its own 'recovery_offset' showing how far
recovery has progressed on the device.
As the only real significance of this is that fact that it can
be stored in the metadata and recovered at restart, and as
only 1.x metadata can do this, we were only updating
'recovery_offset' to 'curr_resync_completed' when updating
v1.x metadata.
But this is wrong, and we will shortly make limited use of this
field in v0.90 metadata.
So move the update into common code.
Signed-off-by: NeilBrown <neilb@suse.de>
something-bility is spelled as something-blity
so a grep for 'blit' would find these lines
this is so trivial that I didn't split it by subsystem / copy
additional maintainers - all changes are to comments
The only purpose is to get fewer false positives when grepping
around the kernel sources.
Signed-off-by: Dirk Hohndel <hohndel@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This value is visible through sysfs and is used by mdadm
when it manages a reshape (backing up data that is about to be
rearranged). So it is important that it is always correct.
Current it does not get updated properly when a reshape
starts which can cause problems when assembling an array
that is in the middle of being reshaped.
This is suitable for 2.6.31.y stable kernels.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
If a 'sync_max' has been set (via sysfs), it is wrong to clear it
until a resync (or reshape or recovery ...) actually reached that
point.
So if a resync is interrupted (e.g. by device failure),
leave 'resync_max' unchanged.
This is particularly important for 'reshape' operations that do not
change the size of the array. For such operations mdadm needs to
monitor the reshape taking rolling backups of the section being
reshaped. If resync_max gets cleared, the reshape can get ahead of
mdadm and then the backups that mdadm creates are useless.
This is suitable for 2.6.31.y stable kernels.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
* 'for-linus' of git://neil.brown.name/md:
async_tx: fix asynchronous raid6 recovery for ddf layouts
async_pq: rename scribble page
async_pq: kill a stray dma_map() call and other cleanups
md/raid6: kill a gcc-4.0.1 'uninitialized variable' warning
raid6/async_tx: handle holes in block list in async_syndrome_val
md/async: don't pass a memory pointer as a page pointer.
md: Fix handling of raid5 array which is being reshaped to fewer devices.
md: fix problems with RAID6 calculations for DDF.
md/raid456: downlevel multicore operations to raid_run_ops
md: drivers/md/unroll.pl replaced with awk analog
md: remove clumsy usage of do_sync_mapping_range from bitmap code
md: raid1/raid10: handle allocation errors during array setup.
md/raid5: initialize conf->device_lock earlier
md/raid1/raid10: add a cond_resched
Revert "md: do not progress the resync process if the stripe was blocked"
Allow the snapshot chunk size to be smaller than the page size
The code is now capable of handling this due to some previous
fixes and enhancements.
As the page size varies between computers, prior to this patch,
the chunk size of a snapshot dictated which machines could read it:
Snapshots created on one machine might not be readable on another.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Use unsigned integer chunk size.
Maximum chunk size is 512kB, there won't ever be need to use 4GB chunk size,
so the number can be 32-bit. This fixes compiler failure on 32-bit systems
with large block devices.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch locks the snapshot when returning status. It fixes a race
when it could return an invalid number of free chunks if someone
was simultaneously modifying it.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Properly close the device if failing because of an invalid chunk size.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
If we are creating snapshot with memory-stored exception store, fail if
the user didn't specify chunk size. Zero chunk size would probably crash
a lot of places in the rest of snapshot code.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Multiple instances of dec_pending() can run concurrently so a lock is
needed when it saves the first error code.
I have never experienced actual problem without locking and just found
this during code inspection while implementing the barrier support
patch for request-based dm.
This patch adds the locking.
I've done compile, boot and basic I/O testings.
Cc: stable@kernel.org
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>
Add missing del_gendisk() to error path when creation of workqueue fails.
Otherwice there is a resource leak and following warning is shown:
WARNING: at fs/sysfs/dir.c:487 sysfs_add_one+0xc5/0x160()
sysfs: cannot create duplicate filename '/devices/virtual/block/dm-0'
Cc: stable@kernel.org
Signed-off-by: Zdenek Kabelac <zkabelac@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
mips:
drivers/md/dm-log-userspace-base.c: In function `userspace_ctr':
drivers/md/dm-log-userspace-base.c:159: warning: cast from pointer to integer of different size
Cc: stable@kernel.org
Cc: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
While initializing the snapshot module, if we fail to register
the snapshot target then we must back-out the exception store
module initialization.
Cc: stable@kernel.org
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Avoid a race causing corruption when snapshots of the same origin have
different chunk sizes by sorting the internal list of snapshots by chunk
size, largest first.
https://bugzilla.redhat.com/show_bug.cgi?id=182659
For example, let's have two snapshots with different chunk sizes. The
first snapshot (1) has small chunk size and the second snapshot (2) has
large chunk size. Let's have chunks A, B, C in these snapshots:
snapshot1: ====A==== ====B====
snapshot2: ==========C==========
(Chunk size is a power of 2. Chunks are aligned.)
A write to the origin at a position within A and C comes along. It
triggers reallocation of A, then reallocation of C and links them
together using A as the 'primary' exception.
Then another write to the origin comes along at a position within B and
C. It creates pending exception for B. C already has a reallocation in
progress and it already has a primary exception (A), so nothing is done
to it: B and C are not linked.
If the reallocation of B finishes before the reallocation of C, because
there is no link with the pending exception for C it does not know to
wait for it and, the second write is dispatched to the origin and causes
data corruption in the chunk C in snapshot2.
To avoid this situation, we maintain snapshots sorted in descending
order of chunk size. This leads to a guaranteed ordering on the links
between the pending exceptions and avoids the problem explained above -
both A and B now get linked to C.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
md/raid6 passes a list of 'struct page *' to the async_tx routines,
which then either DMA map them for offload, or take the page_address
for CPU based calculations.
For RAID6 we sometime leave 'blanks' in the list of pages.
For CPU based calcs, we want to treat theses as a page of zeros.
For offloaded calculations, we simply don't pass a page to the
hardware.
Currently the 'blanks' are encoded as a pointer to
raid6_empty_zero_page. This is a 4096 byte memory region, not a
'struct page'. This is mostly handled correctly but is rather ugly.
So change the code to pass and expect a NULL pointer for the blanks.
When taking page_address of a page, we need to check for a NULL and
in that case use raid6_empty_zero_page.
Signed-off-by: NeilBrown <neilb@suse.de>
When a raid5 (or raid6) array is being reshaped to have fewer devices,
conf->raid_disks is the latter and hence smaller number of devices.
However sometimes we want to use a number which is the total number of
currently required devices - the larger of the 'old' and 'new' sizes.
Before we implemented reducing the number of devices, this was always
'new' i.e. ->raid_disks.
Now we need max(raid_disks, previous_raid_disks) in those places.
This particularly affects assembling an array that was shutdown while
in the middle of a reshape to fewer devices.
md.c needs a similar fix when interpreting the md metadata.
Signed-off-by: NeilBrown <neilb@suse.de>
The percpu conversion allowed a straightforward handoff of stripe
processing to the async subsytem that initially showed some modest gains
(+4%). However, this model is too simplistic and leads to stripes
bouncing between raid5d and the async thread pool for every invocation
of handle_stripe(). As reported by Holger this can fall into a
pathological situation severely impacting throughput (6x performance
loss).
By downleveling the parallelism to raid_run_ops the pathological
stripe_head bouncing is eliminated. This version still exhibits an
average 11% throughput loss for:
mdadm --create /dev/md0 /dev/sd[b-q] -n 16 -l 6
echo 1024 > /sys/block/md0/md/stripe_cache_size
dd if=/dev/zero of=/dev/md0 bs=1024k count=2048
...but the results are at least stable and can be used as a base for
further multicore experimentation.
Reported-by: Holger Kiehl <Holger.Kiehl@dwd.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
drivers/md/unroll.pl replaced by awk script to drop build-time
dependency on perl
Signed-off-by: Vladimir Dronnikov <dronnikov@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
and replace with vfs_fsync which is much neater (but wasn't exported,
or even in existence at the time the code was written).
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Both raid1 and raid10 create a mempool during startup.
If the 'alloc' function for this mempool fails, unplug_slaves
is called.
If that happens when the pool is being initialised, unplug_slaves
will try to use the 'conf' structure that isn't filled in yet, and
badness will happen.
So ensure that unplug_slaves doesn't get called unless we know
that the conf structure if fully initialised.
Signed-off-by: NeilBrown <neilb@suse.de>
Deallocating a raid5_conf_t structure requires taking 'device_lock'.
Ensure it is initialized before it is used, i.e. initialize the lock
before attempting any further initializations that might fail.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
During 'check' of a raid1 or raid10 it is possible for the management
thread to spend a lot of time running 'memcmp' on blocks from
different devices, so make sure the thread has a chance to schedule.
raid5d already has a cond_resched (in process_stripe).
Reported-By: Lee Howard <faxguy@howardsilvan.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This reverts commit df10cfbc4d.
This patch was based on a misunderstanding and risks introducing a busy-wait loop.
So revert it.
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Commit a9327cac44 added seperate read
and write statistics of in_flight requests. And exported the number
of read and write requests in progress seperately through sysfs.
But Corrado Zoccolo <czoccolo@gmail.com> reported getting strange
output from "iostat -kx 2". Global values for service time and
utilization were garbage. For interval values, utilization was always
100%, and service time is higher than normal.
So this was reverted by commit 0f78ab9899
The problem was in part_round_stats_single(), I missed the following:
if (now == part->stamp)
return;
- if (part->in_flight) {
+ if (part_in_flight(part)) {
__part_stat_add(cpu, part, time_in_queue,
part_in_flight(part) * (now - part->stamp));
__part_stat_add(cpu, part, io_ticks, (now - part->stamp));
With this chunk included, the reported regression gets fixed.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
--
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (41 commits)
Revert "Seperate read and write statistics of in_flight requests"
cfq-iosched: don't delay async queue if it hasn't dispatched at all
block: Topology ioctls
cfq-iosched: use assigned slice sync value, not default
cfq-iosched: rename 'desktop' sysfs entry to 'low_latency'
cfq-iosched: implement slower async initiate and queue ramp up
cfq-iosched: delay async IO dispatch, if sync IO was just done
cfq-iosched: add a knob for desktop interactiveness
Add a tracepoint for block request remapping
block: allow large discard requests
block: use normal I/O path for discard requests
swapfile: avoid NULL pointer dereference in swapon when s_bdev is NULL
fs/bio.c: move EXPORT* macros to line after function
Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs
cciss: fix build when !PROC_FS
block: Do not clamp max_hw_sectors for stacking devices
block: Set max_sectors correctly for stacking devices
cciss: cciss_host_attr_groups should be const
cciss: Dynamically allocate the drive_info_struct for each logical drive.
cciss: Add usage_count attribute to each logical drive in /sys
...
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Recently Jens has changed bio_rw_flagged() logic by following
commit 1f98a13f62. Now it returns
bool instead of int. This broke raid1/raid10 RW bits manipulation logic.
One of visible result is BUG_ON triggering due to empty barrier
here scsi_lib.c:1108 scsi_setup_fs_cmnd()
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Recent commit bbba809e96
replaced mempool_create_kzalloc_pool with mempool_create_kmalloc_pool
plus a memset.
This memset is not needed (and we didn't need kzalloc in the first
place).
Ever field of the allocated structure (struct multipath_bh) is
initialised immediately except retry_list, and memset does not
initial a list_head anyway.
To remove the memset.
Signed-off-by: NeilBrown <neilb@suse.de>
The management thread for raid4,5,6 arrays are all called
mdX_raid5, independent of the actual raid level, which is wrong and
can be confusion.
So change md_register_thread to use the name from the personality
unless no alternate name (like 'resync' or 'reshape') is given.
This is simpler and more correct.
Cc: Jinzc <zhenchengjin@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Robert Becker