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>
* '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
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>
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>
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>
The md_notify_reboot() method includes a call to mdelay(1000),
to deal with "exotic SCSI devices" which are too volatile on
reboot. The delay is unconditional. Even if the machine does
not have any block devices, let alone MD devices, the kernel
shutdown sequence is slowed down.
1 second does not matter much with physical hardware, but with
certain virtualization use cases any wasted time in the bootup
& shutdown sequence counts for alot.
* drivers/md/md.c: md_notify_reboot() - only impose a delay if
there was at least one MD device to be stopped during reboot
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Two related problems:
1/ some error paths call "md_unregister_thread(mddev->thread)"
without subsequently clearing ->thread. A subsequent call
to mddev_unlock will try to wake the thread, and crash.
2/ Most calls to md_wakeup_thread are protected against the thread
disappeared either by:
- holding the ->mutex
- having an active request, so something else must be keeping
the array active.
However mddev_unlock calls md_wakeup_thread after dropping the
mutex and without any certainty of an active request, so the
->thread could theoretically disappear.
So we need a spinlock to provide some protections.
So change md_unregister_thread to take a pointer to the thread
pointer, and ensure that it always does the required locking, and
clears the pointer properly.
Reported-by: "Moshe Melnikov" <moshe@zadarastorage.com>
Signed-off-by: NeilBrown <neilb@suse.de>
cc: stable@kernel.org
There is very little benefit in allowing to let a ->make_request
instance update the bios device and sector and loop around it in
__generic_make_request when we can archive the same through calling
generic_make_request from the driver and letting the loop in
generic_make_request handle it.
Note that various drivers got the return value from ->make_request and
returned non-zero values for errors.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
0.90 metadata uses an unsigned 32bit number to count the number of
kilobytes used from each device.
This should allow up to 4TB per device.
However we multiply this by 2 (to get sectors) before casting to a
larger type, so sizes above 2TB get truncated.
Also we allow rdev->sectors to be larger than 4TB, so it is possible
for the array to be resized larger than the metadata can handle.
So make sure rdev->sectors never exceeds 4TB when 0.90 metadata is in
used.
Also the sanity check at the end of super_90_load should include level
1 as it used ->size too. (RAID0 and Linear don't use ->size at all).
Reported-by: Pim Zandbergen <P.Zandbergen@macroscoop.nl>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
When the 'blocked' flag on a device is cleared while there are
unacknowledged bad blocks we must fail the device. This is needed for
backwards compatability of the interface.
The code currently uses the wrong test for "unacknowledged bad blocks
exist". Change it to the right test.
Signed-off-by: NeilBrown <neilb@suse.de>
Queue idling is used for the anticipation of immediate
sequencial I/O's but md_super_write() is a kind of one-
shot operation, coupled with md_super_wait(), so the
idling in this case will be just a waste of time.
Specifying REQ_NOIDLE prevents it. Instead of adding
the flag to submit_bio() directly, use pre-defined
macro WRITE_FLUSH_FUA.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
The 'write-mostly' flag can be changed through sysfs.
With 0.90 metadata, those changes are reflected in the metadata.
For 1.x metadata, they aren't.
So fix super_1_sync to record 'write-mostly' status.
Signed-off-by: NeilBrown <neilb@suse.de>
Sometimes a device will refuse to be set faulty. e.g. RAID1 will
never let the last working device become faulty.
So check if "md_error()" did manage to set the faulty flag and fail
with EBUSY if it didn't.
Resolves-Debian-Bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=601198
Reported-by: Mike Hommey <mh+reportbug@glandium.org>
Signed-off-by: NeilBrown <neilb@suse.de>
* 'for-linus' of git://neil.brown.name/md: (75 commits)
md/raid10: handle further errors during fix_read_error better.
md/raid10: Handle read errors during recovery better.
md/raid10: simplify read error handling during recovery.
md/raid10: record bad blocks due to write errors during resync/recovery.
md/raid10: attempt to fix read errors during resync/check
md/raid10: Handle write errors by updating badblock log.
md/raid10: clear bad-block record when write succeeds.
md/raid10: avoid writing to known bad blocks on known bad drives.
md/raid10 record bad blocks as needed during recovery.
md/raid10: avoid reading known bad blocks during resync/recovery.
md/raid10 - avoid reading from known bad blocks - part 3
md/raid10: avoid reading from known bad blocks - part 2
md/raid10: avoid reading from known bad blocks - part 1
md/raid10: Split handle_read_error out from raid10d.
md/raid10: simplify/reindent some loops.
md/raid5: Clear bad blocks on successful write.
md/raid5. Don't write to known bad block on doubtful devices.
md/raid5: write errors should be recorded as bad blocks if possible.
md/raid5: use bad-block log to improve handling of uncorrectable read errors.
md/raid5: avoid reading from known bad blocks.
...
When recovering one or more devices, if all the good devices have
bad blocks we should record a bad block on the device being rebuilt.
If this fails, we need to abort the recovery.
To ensure we don't think that we aborted later than we actually did,
we need to move the check for MD_RECOVERY_INTR earlier in md_do_sync,
in particular before mddev->curr_resync is updated.
Signed-off-by: NeilBrown <neilb@suse.de>
It is only safe to choose not to write to a bad block if that bad
block is safely recorded in metadata - i.e. if it has been
'acknowledged'.
If it hasn't we need to wait for the acknowledgement.
We support that using rdev->blocked wait and
md_wait_for_blocked_rdev by introducing a new device flag
'BlockedBadBlock'.
This flag is only advisory.
It is cleared whenever we acknowledge a bad block, so that a waiter
can re-check the particular bad blocks that it is interested it.
It should be set by a caller when they find they need to wait.
This (set after test) is inherently racy, but as
md_wait_for_blocked_rdev already has a timeout, losing the race will
have minimal impact.
When we clear "Blocked" was also clear "BlockedBadBlocks" incase it
was set incorrectly (see above race).
We also modify the way we manage 'Blocked' to fit better with the new
handling of 'BlockedBadBlocks' and to make it consistent between
externally managed and internally managed metadata. This requires
that each raidXd loop checks if the metadata needs to be written and
triggers a write (md_check_recovery) if needed. Otherwise a queued
write request might cause raidXd to wait for the metadata to write,
and only that thread can write it.
Before writing metadata, we set FaultRecorded for all devices that
are Faulty, then after writing the metadata we clear Blocked for any
device for which the Fault was certainly Recorded.
The 'faulty' device flag now appears in sysfs if the device is faulty
*or* it has unacknowledged bad blocks. So user-space which does not
understand bad blocks can continue to function correctly.
User space which does, should not assume a device is faulty until it
sees the 'faulty' flag, and then sees the list of unacknowledged bad
blocks is empty.
Signed-off-by: NeilBrown <neilb@suse.de>
If a device has ever seen a write error, we will want to handle
known-bad-blocks differently.
So create an appropriate state flag and export it via sysfs.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Now that we have a bad block list, we should not read from those
blocks.
There are several main parts to this:
1/ read_balance needs to check for bad blocks, and return not only
the chosen device, but also how many good blocks are available
there.
2/ fix_read_error needs to avoid trying to read from bad blocks.
3/ read submission must be ready to issue multiple reads to
different devices as different bad blocks on different devices
could mean that a single large read cannot be served by any one
device, but can still be served by the array.
This requires keeping count of the number of outstanding requests
per bio. This count is stored in 'bi_phys_segments'
4/ retrying a read needs to also be ready to submit a smaller read
and queue another request for the rest.
This does not yet handle bad blocks when reading to perform resync,
recovery, or check.
'md_trim_bio' will also be used for RAID10, so put it in md.c and
export it.
Signed-off-by: NeilBrown <neilb@suse.de>
Space must have been allocated when array was created.
A feature flag is set when the badblock list is non-empty, to
ensure old kernels don't load and trust the whole device.
We only update the on-disk badblocklist when it has changed.
If the badblocklist (or other metadata) is stored on a bad block, we
don't cope very well.
If metadata has no room for bad block, flag bad-blocks as disabled,
and do the same for 0.90 metadata.
Signed-off-by: NeilBrown <neilb@suse.de>
This can show the log (providing it fits in one page) and
allows bad blocks to be 'acknowledged' meaning that they
have safely been recorded in metadata.
Clearing bad blocks is not allowed via sysfs (except for
code testing). A bad block can only be cleared when
a write to the block succeeds.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
This the first step in allowing md to track bad-blocks per-device so
that we can fail individual blocks rather than the whole device.
This patch just adds a data structure for recording bad blocks, with
routines to add, remove, search the list.
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
When calling bioset_create we pass the size of the front_pad as
sizeof(mddev)
which looks suspicious as mddev is a pointer and so it looks like a
common mistake where
sizeof(*mddev)
was intended.
The size is actually correct as we want to store a pointer in the
front padding of the bios created by the bioset, so make the intent
more explicit by using
sizeof(mddev_t *)
Reported-by: Zdenek Kabelac <zdenek.kabelac@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This patch causes MD to generate an event (for device-mapper) when the
synchronization thread is reaped. This is expected behavior for device-mapper.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
page_address() returns void pointer, so the casts can be removed.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
If we hit a read error while recovering a mirror, we want to abort the
recovery without necessarily failing the disk - as having a disk this
a read error is better than not having an array at all.
Currently this is managed with a per-array flag "recovery_disabled"
and is only implemented for RAID1. For RAID10 we will need finer
grained control as we might want to disable recovery for individual
devices separately.
So push more of the decision making into the personality.
'recovery_disabled' is now a 'cookie' which is copied when the
personality want to disable recovery and is changed when a device is
added to the array as this is used as a trigger to 'try recovery
again'.
This will allow RAID10 to get the control that it needs.
Signed-off-by: NeilBrown <neilb@suse.de>
Commit c89a8eee61 ("Allow faulty devices to be removed from a
readonly array.") added some work on ro array in the function,
but it couldn't be done since we didn't allow the ro array to be
handled from the beginning. Fix it.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
There are places where sysfs links to rdev are handled
in a same way. Add the helper functions to consolidate
them.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Moving the event counter into the dynamically allocated 'struc seq_file'
allows poll() support without the need to allocate its own tracking
structure.
All current users are switched over to use the new counter.
Requested-by: Andrew Morton akpm@linux-foundation.org
Acked-by: NeilBrown <neilb@suse.de>
Tested-by: Lucas De Marchi lucas.demarchi@profusion.mobi
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
If a device fails in a way that causes pending request to take a while
to complete, md will not be able to immediately remove it from the
array in remove_and_add_spares.
It will then incorrectly look like a spare device and md will try to
recover it even though it is failed.
This leads to a recovery process starting and instantly aborting over
and over again.
We should check if the device is faulty before considering it to be a
spare. This will avoid trying to start a recovery that cannot
proceed.
This bug was introduced in 2.6.26 so that patch is suitable for any
kernel since then.
Cc: stable@kernel.org
Reported-by: Jim Paradis <james.paradis@stratus.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Add the 'sync_super' function pointer to MD array structure (struct mddev_s)
If device-mapper (dm-raid.c) is to define its own on-disk superblock and be
able to load it, there must still be a way for MD to initiate superblock
updates. The simplest way to make this happen is to provide a pointer in
the MD array structure that can be set by device-mapper (or other module)
with a function to do this. If the function has been set, it will be used;
otherwise, the method with be looked up via 'super_types' as usual.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Move personality and sync/recovery thread starting outside md_run.
Moving the wakeup's of the personality and sync/recovery threads out of
md_run and into do_md_run and mddev_resume solves two issues:
1) It allows bitmap_load to be called before the sync_thread is run and
2) when MD personalities are used by device-mapper (dm-raid.c), the start-up
of the array is better alligned with device-mapper primatives
(CTR/resume/suspend/DTR). I/O - in this case, recovery operations - should
not happen until after a resume has taken place.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Make message a bit clearer by s/blocks/k/
I chose 'k' vs 'kiB' or 'kB' because it is what is used earlier in the
message. 'k' may be a bit ambigous, but I think it's better than "blocks"
which normally means 512, but means 1024 in MD.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Disallow resync I/O while the RAID array is suspended.
Recovery, resync, and metadata I/O should not be allowed while a device is
suspended.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Don't attempt md_integrity_register if there is no gendisk struct available.
When MD arrays are built via device-mapper, the gendisk structure is not
available via mddev.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
The sysfs attribute 'resync_start' (known internally as recovery_cp),
records where a resync is up to. A value of 0 means the array is
not known to be in-sync at all. A value of MaxSector means the array
is believed to be fully in-sync.
When the size of member devices of an array (RAID1,RAID4/5/6) is
increased, the array can be increased to match. This process sets
resync_start to the old end-of-device offset so that the new part of
the array gets resynced.
However with RAID1 (and RAID6) a resync is not technically necessary
and may be undesirable. So it would be good if the implied resync
after the array is resized could be avoided.
So: change 'resync_start' so the value can be changed while the array
is active, and as a precaution only allow it to be changed while
resync/recovery is 'frozen'. Changing it once resync has started is
not going to be useful anyway.
This allows the array to be resized without a resync by:
write 'frozen' to 'sync_action'
write new size to 'component_size' (this will set resync_start)
write 'none' to 'resync_start'
write 'idle' to 'sync_action'.
Also slightly improve some tests on recovery_cp when resizing
raid1/raid5. Now that an arbitrary value could be set we should be
more careful in our tests.
Signed-off-by: NeilBrown <neilb@suse.de>
The 'add_new_disk' ioctl can be used to add a device either as a
spare, or as an active disk that just needs to be resynced based on
write-intent-bitmap information (re-add)
Currently if a re-add is requested but fails we add as a spare
instead. This makes it impossible for user-space to check for
failure.
So change to require that a re-add attempt will either succeed or
completely fail. User-space can then decide what to do next.
Signed-off-by: NeilBrown <neilb@suse.de>
There is a race when creating an md device by opening /dev/mdXX.
If two processes do this at much the same time they will follow the
call path
__blkdev_get -> get_gendisk -> kobj_lookup
The first will call
-> md_probe -> md_alloc -> add_disk -> blk_register_region
and the race happens when the second gets to kobj_lookup after
add_disk has called blk_register_region but before it returns to
md_alloc.
In the case the second will not call md_probe (as the probe is already
done) but will get a handle on the gendisk, return to __blkdev_get
which will then call md_open (via the ->open) pointer.
As mddev->gendisk hasn't been set yet, md_open will think something is
wrong an return with ERESTARTSYS.
This can loop endlessly while the first thread makes no progress
through add_disk. Nothing is blocking it, but due to scheduler
behaviour it doesn't get a turn.
So this is essentially a live-lock.
We fix this by simply moving the assignment to mddev->gendisk before
the call the add_disk() so md_open doesn't get confused.
Also move blk_queue_flush earlier because add_disk should be as late
as possible.
To make sure that md_open doesn't complete until md_alloc has done all
that is needed, we take mddev->open_mutex during the last part of
md_alloc. md_open will wait for this.
This can cause a lock-up on boot so Cc:ing for stable.
For 2.6.36 and earlier a different patch will be needed as the
'blk_queue_flush' call isn't there.
Signed-off-by: NeilBrown <neilb@suse.de>
Reported-by: Thomas Jarosch <thomas.jarosch@intra2net.com>
Tested-by: Thomas Jarosch <thomas.jarosch@intra2net.com>
Cc: stable@kernel.org
Problem:
After raid4->raid0 takeover operation, another takeover operation
(e.g raid0->raid10) results "kernel oops".
Root cause:
Variables 'degraded' in mddev structure is not cleared
on raid45->raid0 takeover.
This patch reset this variable.
Signed-off-by: Krzysztof Wojcik <krzysztof.wojcik@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When an md device adds a request to a queue, it can call
mddev_check_plugged.
If this succeeds then we know that the md thread will be woken up
shortly, and ->plug_cnt will be non-zero until then, so some
processing can be delayed.
If it fails, then no unplug callback is expected and the make_request
function needs to do whatever is required to make the request happen.
Signed-off-by: NeilBrown <neilb@suse.de>
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>
We incorrectly returned -EINVAL when none of the devices in the array
had an integrity profile. This in turn prevented mdadm from starting
the metadevice. Fix this so we only return errors on mismatched
profiles and memory allocation failures.
Reported-by: Giacomo Catenazzi <cate@cateee.net>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...
Fix up conflicts in fs/{aio.c,super.c}
MD and DM create a new bio_set for every metadevice. Each bio_set has an
integrity mempool attached regardless of whether the metadevice is
capable of passing integrity metadata. This is a waste of memory.
Instead we defer the allocation decision to MD and DM since we know at
metadevice creation time whether integrity passthrough is needed or not.
Automatic integrity mempool allocation can then be removed from
bioset_create() and we make an explicit integrity allocation for the
fs_bio_set.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Acked-by: Mike Snitzer <snizer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix build failure introduced by s/freezeable/freezable/
workqueue: add system_freezeable_wq
rds/ib: use system_wq instead of rds_ib_fmr_wq
net/9p: replace p9_poll_task with a work
net/9p: use system_wq instead of p9_mux_wq
xfs: convert to alloc_workqueue()
reiserfs: make commit_wq use the default concurrency level
ocfs2: use system_wq instead of ocfs2_quota_wq
ext4: convert to alloc_workqueue()
scsi/scsi_tgt_lib: scsi_tgtd isn't used in memory reclaim path
scsi/be2iscsi,qla2xxx: convert to alloc_workqueue()
misc/iwmc3200top: use system_wq instead of dedicated workqueues
i2o: use alloc_workqueue() instead of create_workqueue()
acpi: kacpi*_wq don't need WQ_MEM_RECLAIM
fs/aio: aio_wq isn't used in memory reclaim path
input/tps6507x-ts: use system_wq instead of dedicated workqueue
cpufreq: use system_wq instead of dedicated workqueues
wireless/ipw2x00: use system_wq instead of dedicated workqueues
arm/omap: use system_wq in mailbox
workqueue: use WQ_MEM_RECLAIM instead of WQ_RESCUER
With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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>
Revert
b821eaa572
and
f3b99be19d
When I wrote the first of these I had a wrong idea about the
lifetime of 'struct block_device'. It can disappear at any time that
the block device is not open if it falls out of the inode cache.
So relying on the 'size' recorded with it to detect when the
device size has changed and so we need to revalidate, is wrong.
Rather, we really do need the 'changed' attribute stored directly in
the mddev and set/tested as appropriate.
Without this patch, a sequence of:
mknod / open / close / unlink
(which can cause a block_device to be created and then destroyed)
will result in a rescan of the partition table and consequence removal
and addition of partitions.
Several of these in a row can get udev racing to create and unlink and
other code can get confused.
With the patch, the rescan is only performed when needed and so there
are no races.
This is suitable for any stable kernel from 2.6.35.
Reported-by: "Wojcik, Krzysztof" <krzysztof.wojcik@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: stable@kernel.org
'mdp' devices are md devices with preallocated device numbers
for partitions. As such it is possible to mknod and open a partition
before opening the whole device.
this causes md_probe() to be called with a device number of a
partition, which in-turn calls mddev_find with such a number.
However mddev_find expects the number of a 'whole device' and
does the wrong thing with partition numbers.
So add code to mddev_find to remove the 'partition' part of
a device number and just work with the 'whole device'.
This patch addresses https://bugzilla.kernel.org/show_bug.cgi?id=28652
Reported-by: hkmaly@bigfoot.com
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: <stable@kernel.org>
If the desired size of an array is set (via sysfs) before the array is
active (which is the normal sequence), we currrently call set_capacity
immediately.
This means that a subsequent 'open' (as can be caused by some
udev-triggers program) will notice the new size and try to probe for
partitions. However as the array isn't quite ready yet the read will
fail. Then when the array is read, as the size doesn't change again
we don't try to re-probe.
So when setting array size via sysfs, only call set_capacity if the
array is already active.
Signed-off-by: NeilBrown <neilb@suse.de>
md_make_request was calling bio_sectors() for part_stat_add
after it was calling the make_request function. This is
bad because the make_request function can free the bio and
because the bi_size field can change around.
The fix here was suggested by Jens Axboe. It saves the
sector count before the make_request call. I hit this
with CONFIG_DEBUG_PAGEALLOC turned on while trying to break
his pretty fusionio card.
Cc: <stable@kernel.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Activating a spare in an array while resync/recovery is already
happening can lead the that spare being marked in-sync when it isn't
really.
So don't allow the 'slot' to be set (this activating the device)
while resync/recovery is happening.
Signed-off-by: NeilBrown <neilb@suse.de>
There is no need to set this to zero at this point. It will be
set to zero by remove_and_add_spares or at the start of
md_do_sync at the latest.
And setting it to zero before MD_RECOVERY_RUNNING is cleared can
make a 'zero' appear briefly in the 'sync_completed' sysfs attribute
just as resync is finishing.
So simply remove this setting to zero.
Signed-off-by: NeilBrown <neilb@suse.de>
remove_and_add_spares is called in two places where the needs really
are very different.
remove_and_add_spares should not be called on an array which is about
to be reshaped as some extra devices might have been manually added
and that would remove them. However if the array is 'read-auto',
that will currently happen, which is bad.
So in the 'ro != 0' case don't call remove_and_add_spares but simply
remove the failed devices as the comment suggests is needed.
Signed-off-by: NeilBrown <neilb@suse.de>
This flag is not needed and is used badly.
Devices that are included in a native-metadata array are reserved
exclusively for that array - and currently have AllReserved set.
They all are bd_claimed for the rdev and so cannot be shared.
Devices that are included in external-metadata arrays can be shared
among multiple arrays - providing there is no overlap.
These are bd_claimed for md in general - not for a particular rdev.
When changing the amount of a device that is used in an array we need
to check for overlap. This currently includes a check on AllReserved
So even without overlap, sharing with an AllReserved device is not
allowed.
However the bd_claim usage already precludes sharing with these
devices, so the test on AllReserved is not needed. And in fact it is
wrong.
As this is the only use of AllReserved, simply remove all usage and
definition of AllReserved.
Signed-off-by: NeilBrown <neilb@suse.de>
If we try to update_raid_disks and it fails, we should put
'delta_disks' back to zero. This is important because some code,
such as slot_store, assumes that delta_disks has been validated.
Signed-off-by: NeilBrown <neilb@suse.de>
WQ_RESCUER is now an internal flag and should only be used in the
workqueue implementation proper. Use WQ_MEM_RECLAIM instead.
This doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Commit e09b457b (block: simplify holder symlink handling) incorrectly
assumed that there is only one link at maximum. dm may use multiple
links and expects block layer to track reference count for each link,
which is different from and unrelated to the exclusive device holder
identified by @holder when the device is opened.
Remove the single holder assumption and automatic removal of the link
and revive the per-link reference count tracking. The code
essentially behaves the same as before commit e09b457b sans the
unnecessary kobject reference count dancing.
While at it, note that this facility should not be used by anyone else
than the current ones. Sysfs symlinks shouldn't be abused like this
and the whole thing doesn't belong in the block layer at all.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Milan Broz <mbroz@redhat.com>
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-linus' of git://neil.brown.name/md:
md: Fix removal of extra drives when converting RAID6 to RAID5
md: range check slot number when manually adding a spare.
md/raid5: handle manually-added spares in start_reshape.
md: fix sync_completed reporting for very large drives (>2TB)
md: allow suspend_lo and suspend_hi to decrease as well as increase.
md: Don't let implementation detail of curr_resync leak out through sysfs.
md: separate meta and data devs
md-new-param-to_sync_page_io
md-new-param-to-calc_dev_sboffset
md: Be more careful about clearing flags bit in ->recovery
md: md_stop_writes requires mddev_lock.
md/raid5: use sysfs_notify_dirent_safe to avoid NULL pointer
md: Ensure no IO request to get md device before it is properly initialised.
md: Fix single printks with multiple KERN_<level>s
md: fix regression resulting in delays in clearing bits in a bitmap
md: fix regression with re-adding devices to arrays with no metadata
When a RAID6 is converted to a RAID5, the extra drive should
be discarded. However it isn't due to a typo in a comparison.
This bug was introduced in commit e93f68a1fc in 2.6.35-rc4
and is suitable for any -stable since than.
As the extra drive is not removed, the 'degraded' counter is wrong and
so the RAID5 will not respond correctly to a subsequent failure.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
When adding a spare to an active array, we should check the slot
number, but allow it to be larger than raid_disks if a reshape
is being prepared.
Apply the same test when adding a device to an
array-under-construction. It already had most of the test in place,
but not quite all.
Signed-off-by: NeilBrown <neilb@suse.de>
The values exported in the sync_completed file are unsigned long, which
overflows with very large drives, resulting in wrong values reported.
Since sync_completed uses sectors as unit, we'll start getting wrong
values with components larger than 2TB.
This patch simply replaces the use of unsigned long by unsigned long long.
Signed-off-by: Rémi Rérolle <rrerolle@lacie.com>
Signed-off-by: NeilBrown <neilb@suse.de>
The sysfs attributes 'suspend_lo' and 'suspend_hi' describe a region
to which read/writes are suspended so that the under lying data can be
manipulated without user-space noticing.
Currently the window they describe can only move forwards along the
device. However this is an unnecessary restriction which will cause
problems with planned developments.
So relax this restriction and allow these endpoints to move
arbitrarily.
Signed-off-by: NeilBrown <neilb@suse.de>
mddev->curr_resync has artificial values of '1' and '2' which are used
by the code which ensures only one resync is happening at a time on
any given device.
These values are internal and should never be exposed to user-space
(except when translated appropriately as in the 'pending' status in
/proc/mdstat).
Unfortunately they are as ->curr_resync is assigned to
->curr_resync_completed and that value is directly visible through
sysfs.
So change the assignments to ->curr_resync_completed to get the same
valued from elsewhere in a form that doesn't have the magic '1' or '2'
values.
Signed-off-by: NeilBrown <neilb@suse.de>
Allow the metadata to be on a separate device from the
data.
This doesn't mean the data and metadata will by on separate
physical devices - it simply gives device-mapper and userspace
tools more flexibility.
Signed-off-by: NeilBrown <neilb@suse.de>
Add new parameter to 'sync_page_io'.
The new parameter allows us to distinguish between metadata and data
operations. This becomes important later when we add the ability to
use separate devices for data and metadata.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
When we allow for separate devices for data and metadata
in a later patch, we will need to be able to calculate
the superblock offset based on more than the bdev.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Setting ->recovery to 0 is generally not a good idea as it could clear
bits that shouldn't be cleared. In particular, MD_RECOVERY_FROZEN
should only be cleared on explicit request from user-space.
So when we need to clear things, just clear the bits that need
clearing.
As there are a few different places which reap a resync process - and
some do an incomplte job - factor out the code for doing the from
md_check_recovery and call that function instead of open coding part
of it.
Signed-off-by: NeilBrown <neilb@suse.de>
Reported-by: Jonathan Brassow <jbrassow@redhat.com>
As md_stop_writes manipulates the sync_thread and calls md_update_sb,
it need to be called with mddev_lock held.
In all internal cases it is, but the symbol is exported for dm-raid to
call and in that case the lock won't be help.
Do make an exported version which takes the lock, and an internal
version which does not.
Signed-off-by: NeilBrown <neilb@suse.de>
When an md device is in the process of coming on line it is possible
for an IO request (typically a partition table probe) to get through
before the array is fully initialised, which can cause unexpected
behaviour (e.g. a crash).
So explicitly record when the array is ready for IO and don't allow IO
through until then.
There is no possibility for a similar problem when the array is going
off-line as there must only be one 'open' at that time, and it is busy
off-lining the array and so cannot send IO requests. So no memory
barrier is needed in md_stop()
This has been a bug since commit 409c57f380 in 2.6.30 which
introduced md_make_request. Before then, each personality would
register its own make_request_fn when it was ready.
This is suitable for any stable kernel from 2.6.30.y onwards.
Cc: <stable@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Reported-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
commit 589a594be1 (2.6.37-rc4) fixed a problem were md_thread would
sometimes call the ->run function at a bad time.
If an error is detected during array start up after the md_thread has
been started, the md_thread is killed. This resulted in the ->run
function being called once. However the array may not be in a state
that it is safe to call ->run.
However the fix imposed meant that ->run was not called on a timeout.
This means that when an array goes idle, bitmap bits do not get
cleared promptly. While the array is busy the bits will still be
cleared when appropriate so this is not very serious. There is no
risk to data.
Change the test so that we only avoid calling ->run when the thread
is being stopped. This more explicitly addresses the problem situation.
This is suitable for 2.6.37-stable and any -stable kernel to which
589a594be1 was applied.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
block: ensure that completion error gets properly traced
blktrace: add missing probe argument to block_bio_complete
block cfq: don't use atomic_t for cfq_group
block cfq: don't use atomic_t for cfq_queue
block: trace event block fix unassigned field
block: add internal hd part table references
block: fix accounting bug on cross partition merges
kref: add kref_test_and_get
bio-integrity: mark kintegrityd_wq highpri and CPU intensive
block: make kblockd_workqueue smarter
Revert "sd: implement sd_check_events()"
block: Clean up exit_io_context() source code.
Fix compile warnings due to missing removal of a 'ret' variable
fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
cfq-iosched: don't check cfqg in choose_service_tree()
fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
cdrom: export cdrom_check_events()
sd: implement sd_check_events()
sr: implement sr_check_events()
...
Commit 1a855a0606 (2.6.37-rc4) fixed a problem where devices were
re-added when they shouldn't be but caused a regression in a less
common case that means sometimes devices cannot be re-added when they
should be.
In particular, when re-adding a device to an array without metadata
we should always access the device, but after the above commit we
didn't.
This patch sets the In_sync flag in that case so that the re-add
succeeds.
This patch is suitable for any -stable kernel to which 1a855a0606 was
applied.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
cciss: fix cciss_revalidate panic
block: max hardware sectors limit wrapper
block: Deprecate QUEUE_FLAG_CLUSTER and use queue_limits instead
blk-throttle: Correct the placement of smp_rmb()
blk-throttle: Trim/adjust slice_end once a bio has been dispatched
block: check for proper length of iov entries earlier in blk_rq_map_user_iov()
drbd: fix for spin_lock_irqsave in endio callback
drbd: don't recvmsg with zero length
When stacking devices, a request_queue is not always available. This
forced us to have a no_cluster flag in the queue_limits that could be
used as a carrier until the request_queue had been set up for a
metadevice.
There were several problems with that approach. First of all it was up
to the stacking device to remember to set queue flag after stacking had
completed. Also, the queue flag and the queue limits had to be kept in
sync at all times. We got that wrong, which could lead to us issuing
commands that went beyond the max scatterlist limit set by the driver.
The proper fix is to avoid having two flags for tracking the same thing.
We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the
block layer merging functions. The queue_limit 'no_cluster' is turned
into 'cluster' to avoid double negatives and to ease stacking.
Clustering defaults to being enabled as before. The queue flag logic is
removed from the stacking function, and explicitly setting the cluster
flag is no longer necessary in DM and MD.
Reported-by: Ed Lin <ed.lin@promise.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
When we fail to start a raid10 for some reason, we call
md_unregister_thread to kill the thread that was created.
Unfortunately md_thread() will then make one call into the handler
(raid10d) even though md_wakeup_thread has not been called. This is
not safe and as md_unregister_thread is called after mddev->private
has been set to NULL, it will definitely cause a NULL dereference.
So fix this at both ends:
- md_thread should only call the handler if THREAD_WAKEUP has been
set.
- raid10 should call md_unregister_thread before setting things
to NULL just like all the other raid modules do.
This is applicable to 2.6.35 and later.
Cc: stable@kernel.org
Reported-by: "Citizen" <citizen_lee@thecus.com>
Signed-off-by: NeilBrown <neilb@suse.de>
With v0.90 metadata, a hot-spare does not become a full member of the
array until recovery is complete. So if we re-add such a device to
the array, we know that all of it is as up-to-date as the event count
would suggest, and so it a bitmap-based recovery is possible.
However with v1.x metadata, the hot-spare immediately becomes a full
member of the array, but it record how much of the device has been
recovered. If the array is stopped and re-assembled recovery starts
from this point.
When such a device is hot-added to an array we currently lose the 'how
much is recovered' information and incorrectly included it as a full
in-sync member (after bitmap-based fixup).
This is wrong and unsafe and could corrupt data.
So be more careful about setting saved_raid_disk - which is what
guides the re-adding of devices back into an array.
The new code matches the code in slot_store which does a similar
thing, which is encouraging.
This is suitable for any -stable kernel.
Reported-by: "Dailey, Nate" <Nate.Dailey@stratus.com>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
As recorded in
https://bugzilla.kernel.org/show_bug.cgi?id=24012
it is possible for a flush request through md to hang. This is due to
an interaction between the recursion avoidance in
generic_make_request, the insistence in md of only having one flush
active at a time, and the possibility of dm (or md) submitting two
flush requests to a device from the one generic_make_request.
If a generic_make_request call into dm causes two flush requests to be
queued (as happens if the dm table has two targets - they get one
each), these two will be queued inside generic_make_request.
Assume they are for the same md device.
The first is processed and causes 1 or more flush requests to be sent
to lower devices. These get queued within generic_make_request too.
Then the second flush to the md device gets handled and it blocks
waiting for the first flush to complete. But it won't complete until
the two lower-device requests complete, and they haven't even been
submitted yet as they are on the generic_make_request queue.
The deadlock can be broken by using a separate thread to submit the
requests to lower devices. md has such a thread readily available:
md_wq.
So use it to submit these requests.
Reported-by: Giacomo Catenazzi <cate@cateee.net>
Tested-by: Giacomo Catenazzi <cate@cateee.net>
Signed-off-by: NeilBrown <neilb@suse.de>
submit_flushes is called from exactly one place.
Move the code that is before and after that call into
submit_flushes.
This has not functional change, but will make the next patch
smaller and easier to follow.
Signed-off-by: NeilBrown <neilb@suse.de>
None of the functions called between setting flush_pending to 1, and
atomic_dec_and_test can change flush_pending, or will anything
running in any other thread (as ->flush_bio is not NULL). So the
atomic_dec_and_test will always succeed.
So remove the atomic_sec and the atomic_dec_and_test.
Signed-off-by: NeilBrown <neilb@suse.de>
Before 2.6.37, the md layer had a mechanism for catching I/Os with the
barrier flag set, and translating the barrier into barriers for all
the underlying devices. With 2.6.37, I/O barriers have become plain
old flushes, and the md code was updated to reflect this. However,
one piece was left out -- the md layer does not tell the block layer
that it supports flushes or FUA access at all, which results in md
silently dropping flush requests.
Since the support already seems there, just add this one piece of
bookkeeping.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When trying to grow an array by enlarging component devices,
rdev_size_store() expects the return value of rdev_size_change() to be
in sectors, but the actual value is returned in KBs.
This functionality was broken by commit
dd8ac336c1
so this patch is suitable for any kernel since 2.6.30.
Cc: stable@kernel.org
Signed-off-by: Justin Maggard <jmaggard10@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().
blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.
All users are converted. Most conversions are mechanical and don't
introduce any behavior difference. There are several exceptions.
* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
reason to OR it explicitly on blkdev_put().
* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
sb->s_mode.
* With the above changes, sb->s_mode now always should contain
FMODE_EXCL. WARN_ON_ONCE() added to kill_block_super() to detect
errors.
The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Over time, block layer has accumulated a set of APIs dealing with bdev
open, close, claim and release.
* blkdev_get/put() are the primary open and close functions.
* bd_claim/release() deal with exclusive open.
* open/close_bdev_exclusive() are combination of open and claim and
the other way around, respectively.
* bd_link/unlink_disk_holder() to create and remove holder/slave
symlinks.
* open_by_devnum() wraps bdget() + blkdev_get().
The interface is a bit confusing and the decoupling of open and claim
makes it impossible to properly guarantee exclusive access as
in-kernel open + claim sequence can disturb the existing exclusive
open even before the block layer knows the current open if for another
exclusive access. Reorganize the interface such that,
* blkdev_get() is extended to include exclusive access management.
@holder argument is added and, if is @FMODE_EXCL specified, it will
gain exclusive access atomically w.r.t. other exclusive accesses.
* blkdev_put() is similarly extended. It now takes @mode argument and
if @FMODE_EXCL is set, it releases an exclusive access. Also, when
the last exclusive claim is released, the holder/slave symlinks are
removed automatically.
* bd_claim/release() and close_bdev_exclusive() are no longer
necessary and either made static or removed.
* bd_link_disk_holder() remains the same but bd_unlink_disk_holder()
is no longer necessary and removed.
* open_bdev_exclusive() becomes a simple wrapper around lookup_bdev()
and blkdev_get(). It also has an unexpected extra bdev_read_only()
test which probably should be moved into blkdev_get().
* open_by_devnum() is modified to take @holder argument and pass it to
blkdev_get().
Most of bdev open/close operations are unified into blkdev_get/put()
and most exclusive accesses are tested atomically at the open time (as
it should). This cleans up code and removes some, both valid and
invalid, but unnecessary all the same, corner cases.
open_bdev_exclusive() and open_by_devnum() can use further cleanup -
rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop
special features. Well, let's leave them for another day.
Most conversions are straight-forward. drbd conversion is a bit more
involved as there was some reordering, but the logic should stay the
same.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: dm-devel@redhat.com
Cc: drbd-dev@lists.linbit.com
Cc: Leo Chen <leochen@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Joern Engel <joern@logfs.org>
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Code to manage symlinks in /sys/block/*/{holders|slaves} are overly
complex with multiple holder considerations, redundant extra
references to all involved kobjects, unused generic kobject holder
support and unnecessary mixup with bd_claim/release functionalities.
Strip it down to what's necessary (single gendisk holder) and make it
use a separate interface. This is a step for cleaning up
bd_claim/release. This patch makes dm-table slightly more complex but
it will be simplified again with further changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Convert direct reads of an inode's i_size to using i_size_read().
i_size_{read,write} use a seqcount to protect reads from accessing
incomple writes. Concurrent i_size_write()s require mutual exclussion
to protect the seqcount that is used by i_size_{read,write}. But
i_size_read() callers do not need to use additional locking.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: NeilBrown <neilb@suse.de>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
NeilBrown