When there is an error copying a chunk dm-snapshot can incorrectly hold
associated bios indefinitely, resulting in hung IO.
The function copy_callback sets pe->error if there was error copying the
chunk, and then calls complete_exception. complete_exception calls
pending_complete on error, otherwise it calls commit_exception with
commit_callback (and commit_callback calls complete_exception).
The persistent exception store (dm-snap-persistent.c) assumes that calls
to prepare_exception and commit_exception are paired.
persistent_prepare_exception increases ps->pending_count and
persistent_commit_exception decreases it.
If there is a copy error, persistent_prepare_exception is called but
persistent_commit_exception is not. This results in the variable
ps->pending_count never returning to zero and that causes some pending
exceptions (and their associated bios) to be held forever.
Fix this by unconditionally calling commit_exception regardless of
whether the copy was successful. A new "valid" parameter is added to
commit_exception -- when the copy fails this parameter is set to zero so
that the chunk that failed to copy (and all following chunks) is not
recorded in the snapshot store. Also, remove commit_callback now that
it is merely a wrapper around pending_complete.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Device mapper used the field bi_private to point to dm_target_io. However,
since kernel 3.15, the bi_private field is unused, and so the targets do
not need to save and restore this field.
This patch removes code that saves and restores bi_private from dm-cache,
dm-snapshot and dm-verity.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Commit 76c44f6d80 introduced the possibly for "Overflow" to be reported
by the snapshot device's status. Older userspace (e.g. lvm2) does not
handle the "Overflow" status response.
Fix this incompatibility by requiring newer userspace code, that can
cope with "Overflow", request the persistent store with overflow support
by using "PO" (Persistent with Overflow) for the snapshot store type.
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Fixes: 76c44f6d80 ("dm snapshot: don't invalidate on-disk image on snapshot write overflow")
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Pull device mapper update from Mike Snitzer:
- a couple small cleanups in dm-cache, dm-verity, persistent-data's
dm-btree, and DM core.
- a 4.1-stable fix for dm-cache that fixes the leaking of deferred bio
prison cells
- a 4.2-stable fix that adds feature reporting for the dm-stats
features added in 4.2
- improve DM-snapshot to not invalidate the on-disk snapshot if
snapshot device write overflow occurs; but a write overflow triggered
through the origin device will still invalidate the snapshot.
- optimize DM-thinp's async discard submission a bit now that late bio
splitting has been included in block core.
- switch DM-cache's SMQ policy lock from using a mutex to a spinlock;
improves performance on very low latency devices (eg. NVMe SSD).
- document DM RAID 4/5/6's discard support
[ I did not pull the slab changes, which weren't appropriate for this
tree, and weren't obviously the right thing to do anyway. At the very
least they need some discussion and explanation before getting merged.
Because not pulling the actual tagged commit but doing a partial pull
instead, this merge commit thus also obviously is missing the git
signature from the original tag ]
* tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm cache: fix use after freeing migrations
dm cache: small cleanups related to deferred prison cell cleanup
dm cache: fix leaking of deferred bio prison cells
dm raid: document RAID 4/5/6 discard support
dm stats: report precise_timestamps and histogram in @stats_list output
dm thin: optimize async discard submission
dm snapshot: don't invalidate on-disk image on snapshot write overflow
dm: remove unlikely() before IS_ERR()
dm: do not override error code returned from dm_get_device()
dm: test return value for DM_MAPIO_SUBMITTED
dm verity: remove unused mempool
dm cache: move wake_waker() from free_migrations() to where it is needed
dm btree remove: remove unused function get_nr_entries()
dm btree: remove unused "dm_block_t root" parameter in btree_split_sibling()
dm cache policy smq: change the mutex to a spinlock
As generic_make_request() is now able to handle arbitrarily sized bios,
it's no longer necessary for each individual block driver to define its
own ->merge_bvec_fn() callback. Remove every invocation completely.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@kernel.org>
Cc: ceph-devel@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md' bits)
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: also remove ->merge_bvec_fn() in dm-thin as well as
dm-era-target, and resolve merge conflicts]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When the snapshot overflows because of a write to the origin, the on-disk
image has to be invalidated. However, when the snapshot overflows because
of a write to the snapshot, the on-disk image doesn't have to be
invalidated. Change the behavior so that the on-disk image is not
invalidated in this case.
When the snapshot overflows, the variable snapshot_overflowed is set.
All writes to the snapshot are disallowed to minimize filesystem
corruption - this condition is cleared when the snapshot is deactivated
and activated.
The user can extend the overflowed snapshot, deactivate and activate it
again, run fsck (if journaling filesystem is not used) mount it and
recover the data.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Currently we have two different ways to signal an I/O error on a BIO:
(1) by clearing the BIO_UPTODATE flag
(2) by returning a Linux errno value to the bi_end_io callback
The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario. Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.
So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for
non-chains") regressed all existing callers that followed this pattern:
1) saving a bio's original bi_end_io
2) wiring up an intermediate bi_end_io
3) restoring the original bi_end_io from intermediate bi_end_io
4) calling bio_endio() to execute the restored original bi_end_io
The regression was due to BIO_CHAIN only ever getting set if
bio_inc_remaining() is called. For the above pattern it isn't set until
step 3 above (step 2 would've needed to establish BIO_CHAIN). As such
the first bio_endio(), in step 2 above, never decremented __bi_remaining
before calling the intermediate bi_end_io -- leaving __bi_remaining with
the value 1 instead of 0. When bio_inc_remaining() occurred during step
3 it brought it to a value of 2. When the second bio_endio() was
called, in step 4 above, it should've called the original bi_end_io but
it didn't because there was an extra reference that wasn't dropped (due
to atomic operations being optimized away since BIO_CHAIN wasn't set
upfront).
Fix this issue by removing the __bi_remaining management complexity for
all callers that use the above pattern -- bio_chain() is the only
interface that _needs_ to be concerned with __bi_remaining. For the
above pattern callers just expect the bi_end_io they set to get called!
Remove bio_endio_nodec() and also remove all bio_inc_remaining() calls
that aren't associated with the bio_chain() interface.
Also, the bio_inc_remaining() interface has been moved local to bio.c.
Fixes: c4cf5261 ("bio: skip atomic inc/dec of ->bi_remaining for non-chains")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Struct bio has an atomic ref count for chained bio's, and we use this
to know when to end IO on the bio. However, most bio's are not chained,
so we don't need to always introduce this atomic operation as part of
ending IO.
Add a helper to elevate the bi_remaining count, and flag the bio as
now actually needing the decrement at end_io time. Rename the field
to __bi_remaining to catch any current users of this doing the
incrementing manually.
For high IOPS workloads, this reduces the overhead of bio_endio()
substantially.
Tested-by: Robert Elliott <elliott@hp.com>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
The "dm snapshot: suspend origin when doing exception handover" commit
fixed a exception store handover bug associated with pending exceptions
to the "snapshot-origin" target.
However, a similar problem exists in snapshot merging. When snapshot
merging is in progress, we use the target "snapshot-merge" instead of
"snapshot-origin". Consequently, during exception store handover, we
must find the snapshot-merge target and suspend its associated
mapped_device.
To avoid lockdep warnings, the target must be suspended and resumed
without holding _origins_lock.
Introduce a dm_hold() function that grabs a reference on a
mapped_device, but unlike dm_get(), it doesn't crash if the device has
the DMF_FREEING flag set, it returns an error in this case.
In snapshot_resume() we grab the reference to the origin device using
dm_hold() while holding _origins_lock (_origins_lock guarantees that the
device won't disappear). Then we release _origins_lock, suspend the
device and grab _origins_lock again.
NOTE to stable@ people:
When backporting to kernels 3.18 and older, use dm_internal_suspend and
dm_internal_resume instead of dm_internal_suspend_fast and
dm_internal_resume_fast.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
In the function snapshot_resume we perform exception store handover. If
there is another active snapshot target, the exception store is moved
from this target to the target that is being resumed.
The problem is that if there is some pending exception, it will point to
an incorrect exception store after that handover, causing a crash due to
dm-snap-persistent.c:get_exception()'s BUG_ON.
This bug can be triggered by repeatedly changing snapshot permissions
with "lvchange -p r" and "lvchange -p rw" while there are writes on the
associated origin device.
To fix this bug, we must suspend the origin device when doing the
exception store handover to make sure that there are no pending
exceptions:
- introduce _origin_hash that keeps track of dm_origin structures.
- introduce functions __lookup_dm_origin, __insert_dm_origin and
__remove_dm_origin that manipulate the origin hash.
- modify snapshot_resume so that it calls dm_internal_suspend_fast() and
dm_internal_resume_fast() on the origin device.
NOTE to stable@ people:
When backporting to kernels 3.12-3.18, use dm_internal_suspend and
dm_internal_resume instead of dm_internal_suspend_fast and
dm_internal_resume_fast.
When backporting to kernels older than 3.12, you need to pick functions
dm_internal_suspend and dm_internal_resume from the commit
fd2ed4d252.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
When the snapshot target is unloaded, snapshot_dtr() waits until
pending_exceptions_count drops to zero. Then, it destroys the snapshot.
Therefore, the function that decrements pending_exceptions_count
should not touch the snapshot structure after the decrement.
pending_complete() calls free_pending_exception(), which decrements
pending_exceptions_count, and then it performs up_write(&s->lock) and it
calls retry_origin_bios() which dereferences s->origin. These two
memory accesses to the fields of the snapshot may touch the dm_snapshot
struture after it is freed.
This patch moves the call to free_pending_exception() to the end of
pending_complete(), so that the snapshot will not be destroyed while
pending_complete() is in progress.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().
So:
Rename wait_on_bit and wait_on_bit_lock to
wait_on_bit_action and wait_on_bit_lock_action
to make it explicit that they need an action function.
Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
which are *not* given an action function but implicitly use
a standard one.
The decision to error-out if a signal is pending is now made
based on the 'mode' argument rather than being encoded in the action
function.
All instances of the old wait_on_bit and wait_on_bit_lock which
can use the new version have been changed accordingly and their
action functions have been discarded.
wait_on_bit{_lock} does not return any specific error code in the
event of a signal so the caller must check for non-zero and
interpolate their own error code as appropriate.
The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"
The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.
A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack. So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).
Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS. CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
to only process a portion of a bio, the remainder being sent in the
next bio. This enables the old dm snapshot-origin target to only
split write bios on chunk boundaries, read bios are now sent to the
origin device unchanged.
. Add DM core support for disabling WRITE SAME if the underlying SCSI
layer disables it due to command failure.
. Reduce lock contention in DM's bio-prison.
. A few small cleanups and fixes to dm-thin and dm-era.
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Merge tag 'dm-3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
"This pull request is later than I'd have liked because I was waiting
for some performance data to help finally justify sending the
long-standing dm-crypt cpu scalability improvements upstream.
Unfortunately we came up short, so those dm-crypt changes will
continue to wait, but it seems we're not far off.
. Add dm_accept_partial_bio interface to DM core to allow DM targets
to only process a portion of a bio, the remainder being sent in the
next bio. This enables the old dm snapshot-origin target to only
split write bios on chunk boundaries, read bios are now sent to the
origin device unchanged.
. Add DM core support for disabling WRITE SAME if the underlying SCSI
layer disables it due to command failure.
. Reduce lock contention in DM's bio-prison.
. A few small cleanups and fixes to dm-thin and dm-era"
* tag 'dm-3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm thin: update discard_granularity to reflect the thin-pool blocksize
dm bio prison: implement per bucket locking in the dm_bio_prison hash table
dm: remove symbol export for dm_set_device_limits
dm: disable WRITE SAME if it fails
dm era: check for a non-NULL metadata object before closing it
dm thin: return ENOSPC instead of EIO when error_if_no_space enabled
dm thin: cleanup noflush_work to use a proper completion
dm snapshot: do not split read bios sent to snapshot-origin target
dm snapshot: allocate a per-target structure for snapshot-origin target
dm: introduce dm_accept_partial_bio
dm: change sector_count member in clone_info from sector_t to unsigned
Change the snapshot-origin target so that only write bios are split on
chunk boundary. Read bios are passed unchanged to the underlying
device, so they don't have to be split.
Later, we could change the target so that it accepts a larger write bio
if it spans an area that is completely covered by snapshot exceptions.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Allocate a per-target dm_origin structure. This is a prerequisite for
the next commit ("dm snapshot: do not split read bios sent to
snapshot-origin target") which adds a new member to this structure.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Pull core block IO changes from Jens Axboe:
"The major piece in here is the immutable bio_ve series from Kent, the
rest is fairly minor. It was supposed to go in last round, but
various issues pushed it to this release instead. The pull request
contains:
- Various smaller blk-mq fixes from different folks. Nothing major
here, just minor fixes and cleanups.
- Fix for a memory leak in the error path in the block ioctl code
from Christian Engelmayer.
- Header export fix from CaiZhiyong.
- Finally the immutable biovec changes from Kent Overstreet. This
enables some nice future work on making arbitrarily sized bios
possible, and splitting more efficient. Related fixes to immutable
bio_vecs:
- dm-cache immutable fixup from Mike Snitzer.
- btrfs immutable fixup from Muthu Kumar.
- bio-integrity fix from Nic Bellinger, which is also going to stable"
* 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits)
xtensa: fixup simdisk driver to work with immutable bio_vecs
block/blk-mq-cpu.c: use hotcpu_notifier()
blk-mq: for_each_* macro correctness
block: Fix memory leak in rw_copy_check_uvector() handling
bio-integrity: Fix bio_integrity_verify segment start bug
block: remove unrelated header files and export symbol
blk-mq: uses page->list incorrectly
blk-mq: use __smp_call_function_single directly
btrfs: fix missing increment of bi_remaining
Revert "block: Warn and free bio if bi_end_io is not set"
block: Warn and free bio if bi_end_io is not set
blk-mq: fix initializing request's start time
block: blk-mq: don't export blk_mq_free_queue()
block: blk-mq: make blk_sync_queue support mq
block: blk-mq: support draining mq queue
dm cache: increment bi_remaining when bi_end_io is restored
block: fixup for generic bio chaining
block: Really silence spurious compiler warnings
block: Silence spurious compiler warnings
block: Kill bio_pair_split()
...
The list of initial exceptions is loaded in the target constructor. We
are allowed to allocate memory with GFP_KERNEL at this point. So,
change alloc_completed_exception to use GFP_KERNEL when being called
from the constructor.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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Merge tag 'v3.13-rc6' into for-3.14/core
Needed to bring blk-mq uptodate, since changes have been going in
since for-3.14/core was established.
Fixup merge issues related to the immutable biovec changes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Conflicts:
block/blk-flush.c
fs/btrfs/check-integrity.c
fs/btrfs/extent_io.c
fs/btrfs/scrub.c
fs/logfs/dev_bdev.c
There is a possible leak of snapshot space in case of crash.
The reason for space leaking is that chunks in the snapshot device are
allocated sequentially, but they are finished (and stored in the metadata)
out of order, depending on the order in which copying finished.
For example, supposed that the metadata contains the following records
SUPERBLOCK
METADATA (blocks 0 ... 250)
DATA 0
DATA 1
DATA 2
...
DATA 250
Now suppose that you allocate 10 new data blocks 251-260. Suppose that
copying of these blocks finish out of order (block 260 finished first
and the block 251 finished last). Now, the snapshot device looks like
this:
SUPERBLOCK
METADATA (blocks 0 ... 250, 260, 259, 258, 257, 256)
DATA 0
DATA 1
DATA 2
...
DATA 250
DATA 251
DATA 252
DATA 253
DATA 254
DATA 255
METADATA (blocks 255, 254, 253, 252, 251)
DATA 256
DATA 257
DATA 258
DATA 259
DATA 260
Now, if the machine crashes after writing the first metadata block but
before writing the second metadata block, the space for areas DATA 250-255
is leaked, it contains no valid data and it will never be used in the
future.
This patch makes dm-snapshot complete exceptions in the same order they
were allocated, thus fixing this bug.
Note: when backporting this patch to the stable kernel, change the version
field in the following way:
* if version in the stable kernel is {1, 11, 1}, change it to {1, 12, 0}
* if version in the stable kernel is {1, 10, 0} or {1, 10, 1}, change it
to {1, 10, 2}
Userspace reads the version to determine if the bug was fixed, so the
version change is needed.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
This adds a generic mechanism for chaining bio completions. This is
going to be used for a bio_split() replacement, and it turns out to be
very useful in a fair amount of driver code - a fair number of drivers
were implementing this in their own roundabout ways, often painfully.
Note that this means it's no longer to call bio_endio() more than once
on the same bio! This can cause problems for drivers that save/restore
bi_end_io. Arguably they shouldn't be saving/restoring bi_end_io at all
- in all but the simplest cases they'd be better off just cloning the
bio, and immutable biovecs is making bio cloning cheaper. But for now,
we add a bio_endio_nodec() for these cases.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
LVM2, since version 2.02.96, creates origin with zero size, then loads
the snapshot driver and then loads the origin. Consequently, the
snapshot driver sees the origin size zero and sets the hash size to the
lower bound 64. Such small hash table causes performance degradation.
This patch changes it so that the hash size is determined by the size of
snapshot volume, not minimum of origin and snapshot size. It doesn't
make sense to set the snapshot size significantly larger than the origin
size, so we do not need to take origin size into account when
calculating the hash size.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Return -ENOMEM instead of success if unable to allocate pending
exception mempool in snapshot_ctr.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch allows the administrator to reduce the rate at which kcopyd
issues I/O.
Each module that uses kcopyd acquires a throttle parameter that can be
set in /sys/module/*/parameters.
We maintain a history of kcopyd usage by each module in the variables
io_period and total_period in struct dm_kcopyd_throttle. The actual
kcopyd activity is calculated as a percentage of time equal to
"(100 * io_period / total_period)". This is compared with the user-defined
throttle percentage threshold and if it is exceeded, we sleep.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Add module aliases so that autoloading works correctly if the user
tries to activate "snapshot-origin" or "snapshot-merge" targets.
Reference: https://bugzilla.redhat.com/889973
Reported-by: Chao Yang <chyang@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Use 'bio' in the name of variables and functions that deal with
bios rather than 'request' to avoid confusion with the normal
block layer use of 'request'.
No functional changes.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Avoid returning a truncated table or status string instead of setting
the DM_BUFFER_FULL_FLAG when the last target of a table fills the
buffer.
When processing a table or status request, the function retrieve_status
calls ti->type->status. If ti->type->status returns non-zero,
retrieve_status assumes that the buffer overflowed and sets
DM_BUFFER_FULL_FLAG.
However, targets don't return non-zero values from their status method
on overflow. Most targets returns always zero.
If a buffer overflow happens in a target that is not the last in the
table, it gets noticed during the next iteration of the loop in
retrieve_status; but if a buffer overflow happens in the last target, it
goes unnoticed and erroneously truncated data is returned.
In the current code, the targets behave in the following way:
* dm-crypt returns -ENOMEM if there is not enough space to store the
key, but it returns 0 on all other overflows.
* dm-thin returns errors from the status method if a disk error happened.
This is incorrect because retrieve_status doesn't check the error
code, it assumes that all non-zero values mean buffer overflow.
* all the other targets always return 0.
This patch changes the ti->type->status function to return void (because
most targets don't use the return code). Overflow is detected in
retrieve_status: if the status method fills up the remaining space
completely, it is assumed that buffer overflow happened.
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch removes map_info from bio-based device mapper targets.
map_info is still used for request-based targets.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Eliminate struct map_info from dm-snap.
map_info->ptr was used in dm-snap to indicate if the bio was tracked.
If map_info->ptr was non-NULL, the bio was linked in tracked_chunk_hash.
This patch removes the use of map_info->ptr. We determine if the bio was
tracked based on hlist_unhashed(&c->node). If hlist_unhashed is true,
the bio is not tracked, if it is false, the bio is tracked.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This patch moves target_request_nr from map_info to dm_target_io and
makes it accessible with dm_bio_get_target_request_nr.
This patch is a preparation for the next patch that removes map_info.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Replace tracked_chunk_pool with per_bio_data in dm-snap.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
track_chunk is always called with interrupts enabled. Consequently, we
do not need to save and restore interrupt state in "flags" variable.
This patch changes spin_lock_irqsave to spin_lock_irq and
spin_unlock_irqrestore to spin_unlock_irq.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Commit outstanding metadata before returning the status for a dm thin
pool so that the numbers reported are as up-to-date as possible.
The commit is not performed if the device is suspended or if
the DM_NOFLUSH_FLAG is supplied by userspace and passed to the target
through a new 'status_flags' parameter in the target's dm_status_fn.
The userspace dmsetup tool will support the --noflush flag with the
'dmsetup status' and 'dmsetup wait' commands from version 1.02.76
onwards.
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Remove the restriction that limits a target's specified maximum incoming
I/O size to be a power of 2.
Rename this setting from 'split_io' to the less-ambiguous 'max_io_len'.
Change it from sector_t to uint32_t, which is plenty big enough, and
introduce a wrapper function dm_set_target_max_io_len() to set it.
Use sector_div() to process it now that it is not necessarily a power of 2.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
If we write a full chunk in the snapshot, skip reading the origin device
because the whole chunk will be overwritten anyway.
This patch changes the snapshot write logic when a full chunk is written.
In this case:
1. allocate the exception
2. dispatch the bio (but don't report the bio completion to device mapper)
3. write the exception record
4. report bio completed
Callbacks must be done through the kcopyd thread, because callbacks must not
race with each other. So we create two new functions:
dm_kcopyd_prepare_callback: allocate a job structure and prepare the callback.
(This function must not be called from interrupt context.)
dm_kcopyd_do_callback: submit callback.
(This function may be called from interrupt context.)
Performance test (on snapshots with 4k chunk size):
without the patch:
non-direct-io sequential write (dd): 17.7MB/s
direct-io sequential write (dd): 20.9MB/s
non-direct-io random write (mkfs.ext2): 0.44s
with the patch:
non-direct-io sequential write (dd): 26.5MB/s
direct-io sequential write (dd): 33.2MB/s
non-direct-io random write (mkfs.ext2): 0.27s
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Return client directly from dm_kcopyd_client_create, not through a
parameter, making it consistent with dm_io_client_create.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reserve just the minimum of pages needed to process one job.
Because we allocate pages from page allocator, we don't need to reserve
a large number of pages. The maximum job size is SUB_JOB_SIZE and we
calculate the number of reserved pages based on this.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
If a table is read-only, also open any log and cow devices it uses read-only.
Previously, even read-only devices were opened read-write internally.
After patch 75f1dc0d07
block: check bdev_read_only() from blkdev_get()
was applied, loading such tables began to fail. The patch
was reverted by e51900f7d3
block: revert block_dev read-only check
but this patch fixes this part of the code to work with the original patch.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Use dm_suspended() rather than having each snapshot target maintain a
private 'suspended' flag in struct dm_snapshot.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm_snapshot->queued_bios_work isn't used. Remove ->queued_bios[_work]
from dm_snapshot structure, the flush_queued_bios work function and
ksnapd workqueue.
The DM snapshot changes that were going to use the ksnapd workqueue were
either superseded (fix for origin write races) or never completed
(deallocation of invalid snapshot's memory via workqueue).
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* 'for-2.6.37/barrier' of git://git.kernel.dk/linux-2.6-block: (46 commits)
xen-blkfront: disable barrier/flush write support
Added blk-lib.c and blk-barrier.c was renamed to blk-flush.c
block: remove BLKDEV_IFL_WAIT
aic7xxx_old: removed unused 'req' variable
block: remove the BH_Eopnotsupp flag
block: remove the BLKDEV_IFL_BARRIER flag
block: remove the WRITE_BARRIER flag
swap: do not send discards as barriers
fat: do not send discards as barriers
ext4: do not send discards as barriers
jbd2: replace barriers with explicit flush / FUA usage
jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier
jbd: replace barriers with explicit flush / FUA usage
nilfs2: replace barriers with explicit flush / FUA usage
reiserfs: replace barriers with explicit flush / FUA usage
gfs2: replace barriers with explicit flush / FUA usage
btrfs: replace barriers with explicit flush / FUA usage
xfs: replace barriers with explicit flush / FUA usage
block: pass gfp_mask and flags to sb_issue_discard
dm: convey that all flushes are processed as empty
...
We have several users of min_not_zero, each of them using their own
definition. Move the define to kernel.h.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
