REQ_SYNC is ignored in current raid5 code. Block layer does use it to do
policy,
for example ioscheduler. This patch adds it.
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
The important issue here is incorporating the different in data_offset
into calculations concerning when we might need to over-write data
that is still thought to be valid.
To this end we find the minimum offset difference across all devices
and add that where appropriate.
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>
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>
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>
On a successful write to a known bad block, flag the sh
so that raid5d can remove the known bad block from the list.
Signed-off-by: NeilBrown <neilb@suse.de>
When a write error is detected, don't mark the device as failed
immediately but rather record the fact for handle_stripe to deal with.
Handle_stripe then attempts to record a bad block. Only if that fails
does the device get marked as faulty.
Signed-off-by: NeilBrown <neilb@suse.de>
If we get an uncorrectable read error - record a bad block rather than
failing the device.
And if these errors (which may be due to known bad blocks) cause
recovery to be impossible, record a bad block on the recovering
devices, or abort the recovery.
As we might abort a recovery without failing a device we need to teach
RAID5 about recovery_disabled handling.
Signed-off-by: NeilBrown <neilb@suse.de>
Adding these three fields will allow more common code to be moved
to handle_stripe()
struct field rearrangement by Namhyung Kim.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
'struct stripe_head_state' stores state about the 'current' stripe
that is passed around while handling the stripe.
For RAID6 there is an extension structure: r6_state, which is also
passed around.
There is no value in keeping these separate, so move the fields from
the latter into the former.
This means that all code now needs to treat s->failed_num as an small
array, but this is a small cost.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
sh->lock is now mainly used to ensure that two threads aren't running
in the locked part of handle_stripe[56] at the same time.
That can more neatly be achieved with an 'active' flag which we set
while running handle_stripe. If we find the flag is set, we simply
requeue the stripe for later by setting STRIPE_HANDLE.
For safety we take ->device_lock while examining the state of the
stripe and creating a summary in 'stripe_head_state / r6_state'.
This possibly isn't needed but as shared fields like ->toread,
->towrite are checked it is safer for now at least.
We leave the label after the old 'unlock' called "unlock" because it
will disappear in a few patches, so renaming seems pointless.
This leaves the stripe 'locked' for longer as we clear STRIPE_ACTIVE
later, but that is not a problem.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
This is the start of a series of patches to remove sh->lock.
sync_request takes sh->lock before setting STRIPE_SYNCING to ensure
there is no race with testing it in handle_stripe[56].
Instead, use a new flag STRIPE_SYNC_REQUESTED and test it early
in handle_stripe[56] (after getting the same lock) and perform the
same set/clear operations if it was set.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
md has some plugging infrastructure for RAID5 to use because the
normal plugging infrastructure required a 'request_queue', and when
called from dm, RAID5 doesn't have one of those available.
This relied on the ->unplug_fn callback which doesn't exist any more.
So remove all of that code, both in md and raid5. Subsequent patches
with restore the plugging functionality.
Signed-off-by: NeilBrown <neilb@suse.de>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This patch converts md to support REQ_FLUSH/FUA instead of now
deprecated REQ_HARDBARRIER. In the core part (md.c), the following
changes are notable.
* Unlike REQ_HARDBARRIER, REQ_FLUSH/FUA don't interfere with
processing of other requests and thus there is no reason to mark the
queue congested while FLUSH/FUA is in progress.
* REQ_FLUSH/FUA failures are final and its users don't need retry
logic. Retry logic is removed.
* Preflush needs to be issued to all member devices but FUA writes can
be handled the same way as other writes - their processing can be
deferred to request_queue of member devices. md_barrier_request()
is renamed to md_flush_request() and simplified accordingly.
For linear, raid0 and multipath, the core changes are enough. raid1,
5 and 10 need the following conversions.
* raid1: Handling of FLUSH/FUA bio's can simply be deferred to
request_queues of member devices. Barrier related logic removed.
* raid5: Queue draining logic dropped. FUA bit is propagated through
biodrain and stripe resconstruction such that all the updated parts
of the stripe are written out with FUA writes if any of the dirtying
writes was FUA. preread_active_stripes handling in make_request()
is updated as suggested by Neil Brown.
* raid10: FUA bit needs to be propagated to write clones.
linear, raid0, 1, 5 and 10 tested.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Neil Brown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
md/raid5 uses the plugging infrastructure provided by the block layer
and 'struct request_queue'. However when we plug raid5 under dm there
is no request queue so we cannot use that.
So create a similar infrastructure that is much lighter weight and use
it for raid5.
Signed-off-by: NeilBrown <neilb@suse.de>
the dm module will need this for dm-raid45.
Also only access ->queue->backing_dev_info->congested_fn
if ->queue actually exists. It won't in a dm target.
Signed-off-by: NeilBrown <neilb@suse.de>
We will shortly allow md devices with no gendisk (they are attached to
a dm-target instead). That will cause mdname() to return 'mdX'.
There is one place where mdname really needs to be unique: when
creating the name for a slab cache.
So in that case, if there is no gendisk, you the address of the mddev
formatted in HEX to provide a unique name.
Signed-off-by: NeilBrown <neilb@suse.de>
