Commit 9470e4a693 only covered the initial bug report, there are
other spots in CFQ where we need to check that we actually have
a valid cfq_group_data structure.
Fixes: e48453c3 ("block, cgroup: implement policy-specific per-blkcg data")
Signed-off-by: Jens Axboe <axboe@fb.com>
If none of the devices in the system are using CFQ, then attempting to
read:
/sys/fs/cgroup/blkio/blkio.leaf_weight
will results in a NULL dereference. Check for a valid cfq_group_data
struct before attempting to dereference it.
Reported-by: Andrey Wagin <avagin@gmail.com>
Fixes: e48453c3 ("block, cgroup: implement policy-specific per-blkcg data")
Signed-off-by: Jens Axboe <axboe@fb.com>
If CFQ_GROUP_IOSCHED is not set, the compiler produces the
following warning:
CC block/cfq-iosched.o
linux/block/cfq-iosched.c:469:2:
warning: 'cpd_to_cfqgd' defined but not used [-Wunused-function]
*cpd_to_cfqgd(struct blkcg_policy_data *cpd)
^
In reality, two other lookup functions aren't used either if
CFQ_GROUP_IOSCHED isn't set. Move all three under one of the
CFQ_GROUP_IOSCHED sections in the code.
Reported-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
A previous commit wanted to make CFQ default to IOPS mode on
non-rotational storage, however it did so when the queue was
initialized and the non-rotational flag is only set later on
in the probe.
Add an elevator hook that gets called off the add_disk() path,
at that point we know that feature probing has finished, and
we can reliably check for the various flags that drivers can
set.
Fixes: 41c0126b ("block: Make CFQ default to IOPS mode on SSDs")
Tested-by: Romain Francoise <romain@orebokech.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
blktrace.c is currently maintained by Jens Axboe as it is used for
debugging the block layer. That file should be added to the MAINTAINERS
file under BLOCK LAYER, such that people will know to Cc the BLOCK
LAYER maintainer when modifying that file.
Currently:
$ scripts/get_maintainer.pl -f kernel/trace/blktrace.c
Steven Rostedt <rostedt@goodmis.org> (maintainer:TRACING)
Ingo Molnar <mingo@redhat.com> (maintainer:TRACING)
linux-kernel@vger.kernel.org (open list)
After the patch:
$ scripts/get_maintainer.pl -f kernel/trace/blktrace.c
Jens Axboe <axboe@kernel.dk> (maintainer:BLOCK LAYER)
Steven Rostedt <rostedt@goodmis.org> (maintainer:TRACING)
Ingo Molnar <mingo@redhat.com> (maintainer:TRACING)
linux-kernel@vger.kernel.org (open list)
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
The block IO (blkio) controller enables the block layer to provide service
guarantees in a hierarchical fashion. Specifically, service guarantees
are provided by registered request-accounting policies. As of now, a
proportional-share and a throttling policy are available. They are
implemented, respectively, by the CFQ I/O scheduler and the blk-throttle
subsystem. Unfortunately, as for adding new policies, the current
implementation of the block IO controller is only halfway ready to allow
new policies to be plugged in. This commit provides a solution to make
the block IO controller fully ready to handle new policies.
In what follows, we first describe briefly the current state, and then
list the changes made by this commit.
The throttling policy does not need any per-cgroup information to perform
its task. In contrast, the proportional share policy uses, for each cgroup,
both the weight assigned by the user to the cgroup, and a set of dynamically-
computed weights, one for each device.
The first, user-defined weight is stored in the blkcg data structure: the
block IO controller allocates a private blkcg data structure for each
cgroup in the blkio cgroups hierarchy (regardless of which policy is active).
In other words, the block IO controller internally mirrors the blkio cgroups
with private blkcg data structures.
On the other hand, for each cgroup and device, the corresponding dynamically-
computed weight is maintained in the following, different way. For each device,
the block IO controller keeps a private blkcg_gq structure for each cgroup in
blkio. In other words, block IO also keeps one private mirror copy of the blkio
cgroups hierarchy for each device, made of blkcg_gq structures.
Each blkcg_gq structure keeps per-policy information in a generic array of
dynamically-allocated 'dedicated' data structures, one for each registered
policy (so currently the array contains two elements). To be inserted into the
generic array, each dedicated data structure embeds a generic blkg_policy_data
structure. Consider now the array contained in the blkcg_gq structure
corresponding to a given pair of cgroup and device: one of the elements
of the array contains the dedicated data structure for the proportional-share
policy, and this dedicated data structure contains the dynamically-computed
weight for that pair of cgroup and device.
The generic strategy adopted for storing per-policy data in blkcg_gq structures
is already capable of handling new policies, whereas the one adopted with blkcg
structures is not, because per-policy data are hard-coded in the blkcg
structures themselves (currently only data related to the proportional-
share policy).
This commit addresses the above issues through the following changes:
. It generalizes blkcg structures so that per-policy data are stored in the same
way as in blkcg_gq structures.
Specifically, it lets also the blkcg structure store per-policy data in a
generic array of dynamically-allocated dedicated data structures. We will
refer to these data structures as blkcg dedicated data structures, to
distinguish them from the dedicated data structures inserted in the generic
arrays kept by blkcg_gq structures.
To allow blkcg dedicated data structures to be inserted in the generic array
inside a blkcg structure, this commit also introduces a new blkcg_policy_data
structure, which is the equivalent of blkg_policy_data for blkcg dedicated
data structures.
. It adds to the blkcg_policy structure, i.e., to the descriptor of a policy, a
cpd_size field and a cpd_init field, to be initialized by the policy with,
respectively, the size of the blkcg dedicated data structures, and the
address of a constructor function for blkcg dedicated data structures.
. It moves the CFQ-specific fields embedded in the blkcg data structure (i.e.,
the fields related to the proportional-share policy), into a new blkcg
dedicated data structure called cfq_group_data.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
CFQ idling causes reduced IOPS throughput on non-rotational disks.
Since disk head seeking is not applicable to SSDs, it doesn't really
help performance by anticipating future near-by IO requests.
By turning off idling (and switching to IOPS mode), we allow other
processes to dispatch IO requests down to the driver and so increase IO
throughput.
Following FIO benchmark results were taken on a cloud SSD offering with
idling on and off:
Idling iops avg-lat(ms) stddev bw
------------------------------------------------------
On 7054 90.107 38.697 28217KB/s
Off 29255 21.836 11.730 117022KB/s
fio --name=temp --size=100G --time_based --ioengine=libaio \
--randrepeat=0 --direct=1 --invalidate=1 --verify=0 \
--verify_fatal=0 --rw=randread --blocksize=4k --group_reporting=1 \
--filename=/dev/sdb --runtime=10 --iodepth=64 --numjobs=10
And the following is from a local SSD run:
Idling iops avg-lat(ms) stddev bw
------------------------------------------------------
On 19320 33.043 14.068 77281KB/s
Off 21626 29.465 12.662 86507KB/s
fio --name=temp --size=5G --time_based --ioengine=libaio \
--randrepeat=0 --direct=1 --invalidate=1 --verify=0 \
--verify_fatal=0 --rw=randread --blocksize=4k --group_reporting=1 \
--filename=/fio_data --runtime=10 --iodepth=64 --numjobs=10
Reviewed-by: Nauman Rafique <nauman@google.com>
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We export this function and NVMe wants to use it, but for some reason
it was never added to the block header. Do that.
Signed-off-by: Jens Axboe <axboe@fb.com>
Storage controllers may expose multiple block devices that share hardware
resources managed by blk-mq. This patch enhances the shared tags so a
low-level driver can access the shared resources not tied to the unshared
h/w contexts. This way the LLD can dynamically add and delete disks and
request queues without having to track all the request_queue hctx's to
iterate outstanding tags.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We can safely merge anything that wont generate an SG list entry,
so if the bio is data-less (discard), don't look at potential
SG gaps.
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently dm-multipath has to clone the bios for every request sent
to the lower devices, which wastes cpu cycles and ties down memory.
This patch instead adds a new REQ_CLONE flag that instructs req_bio_endio
to not complete bios attached to a request, which we set on clone
requests similar to bios in a flush sequence. With this change I/O
errors on a path failure only get propagated to dm-multipath, which
can then either resubmit the I/O or complete the bios on the original
request.
I've done some basic testing of this on a Linux target with ALUA support,
and it survives path failures during I/O nicely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.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>
The only possible problem of using mutex_lock() instead of trylock
is about deadlock.
If there aren't any locks held before calling blkdev_reread_part(),
deadlock can't be caused by this conversion.
If there are locks held before calling blkdev_reread_part(),
and if these locks arn't required in open, close handler and I/O
path, deadlock shouldn't be caused too.
Both user space's ioctl(BLKRRPART) and md_setup_drive() from
init/do_mounts_md.c belongs to the 1st case, so the conversion is safe
for the two cases.
For loop, the previous patches in this pathset has fixed the ABBA lock
dependency, so the conversion is OK.
For nbd, tx_lock is held when calling the function:
- both open and release won't hold the lock
- when blkdev_reread_part() is run, I/O thread has been stopped
already, so tx_lock won't be acquired in I/O path at that time.
- so the conversion won't cause deadlock for nbd
For dasd, both dasd_open(), dasd_release() and request function don't
acquire any mutex/semphone, so the conversion should be safe.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This patch exports blkdev_reread_part() for block drivers, also
introduce __blkdev_reread_part().
For some drivers, such as loop, reread of partitions can be run
from the release path, and bd_mutex may already be held prior to
calling ioctl_by_bdev(bdev, BLKRRPART, 0), so introduce
__blkdev_reread_part for use in such cases.
CC: Christoph Hellwig <hch@lst.de>
CC: Jens Axboe <axboe@kernel.dk>
CC: Tejun Heo <tj@kernel.org>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: Markus Pargmann <mpa@pengutronix.de>
CC: Stefan Weinhuber <wein@de.ibm.com>
CC: Stefan Haberland <stefan.haberland@de.ibm.com>
CC: Sebastian Ott <sebott@linux.vnet.ibm.com>
CC: Fabian Frederick <fabf@skynet.be>
CC: Ming Lei <ming.lei@canonical.com>
CC: David Herrmann <dh.herrmann@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: nbd-general@lists.sourceforge.net
CC: linux-s390@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Stop abusing struct page functionality and the swap end_io handler, and
instead add a modified version of the blk-lib.c bio_batch helpers.
Also move the block I/O code into swap.c as they are directly tied into
each other.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Ming Lin <mlin@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Jens Axboe <axboe@fb.com>
Various previous patches removed bits and left holes, collapse them
all. Leave the reset start bit where it is, we don't need to change
that.
Signed-off-by: Jens Axboe <axboe@fb.com>
Since the big barrier rewrite/removal in 2007 we never fail FLUSH or
FUA requests, which means we can remove the magic BIO_EOPNOTSUPP flag
to help propagating those to the buffer_head layer.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
lockdep gets unhappy about the not disabling irqs when using the queue_lock
around it. Instead of trying to fix that up just switch to an atomic_t
and get rid of the lock.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Last patch makes plug work for multiple queue case. However it only
works for single disk case, because it assumes only one request in the
plug list. If a task is accessing multiple disks, eg MD/DM, the
assumption is wrong. Let blk_attempt_plug_merge() record request from
the same queue.
V2: use NULL parameter in !mq case. Fix a bug. Add comments in
blk_attempt_plug_merge to make it less (hopefully) confusion.
Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
plug is still helpful for workload with IO merge, but it can be harmful
otherwise especially with multiple hardware queues, as there is
(supposed) no lock contention in this case and plug can introduce
latency. For multiple queues, we do limited plug, eg plug only if there
is request merge. If a request doesn't have merge with following
request, the requet will be dispatched immediately.
V2: check blk_queue_nomerges() as suggested by Jeff.
Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
If we directly issue a request and it fails, we use
blk_mq_merge_queue_io(). But we already assigned bio to a request in
blk_mq_bio_to_request. blk_mq_merge_queue_io shouldn't run
blk_mq_bio_to_request again.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The following appears in blk_sq_make_request:
/*
* If we have multiple hardware queues, just go directly to
* one of those for sync IO.
*/
We clearly don't have multiple hardware queues, here! This comment was
introduced with this commit 07068d5b8e (blk-mq: split make request
handler for multi and single queue):
We want slightly different behavior from them:
- On single queue devices, we currently use the per-process plug
for deferred IO and for merging.
- On multi queue devices, we don't use the per-process plug, but
we want to go straight to hardware for SYNC IO.
The old code had this:
use_plug = !is_flush_fua && ((q->nr_hw_queues == 1) || !is_sync);
and that was converted to:
use_plug = !is_flush_fua && !is_sync;
which is not equivalent. For the single queue case, that second half of
the && expression is always true. So, what I think was actually inteded
follows (and this more closely matches what is done in blk_queue_bio).
V2: delete the 'likely', which should not be a big deal
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Current code looks like inner plug gets flushed with a
blk_finish_plug(). Actually it's a nop. All requests/callbacks are added
to current->plug, while only outmost plug is assigned to current->plug.
So inner plug always has empty request/callback list, which makes
blk_flush_plug_list() a nop. This tries to make the code more clear.
Signed-off-by: Shaohua Li <shli@fb.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This removes the request types and hacks from the block code and into the
old IDE driver. There is a small amunt of code duplication due to this,
but it's not too bad.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
These values are only used by the IDE driver, so move them into it
by allowing drivers to take cmd_type values after the first private
one. Note that we have to turn cmd_type into a plain unsigned integer
so that gcc doesn't complain about mismatching enum types.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Struct bio has a reference count that controls when it can be freed.
Most uses cases is allocating the bio, which then returns with a
single reference to it, doing IO, and then dropping that single
reference. We can remove this atomic_dec_and_test() in the completion
path, if nobody else is holding a reference to the bio.
If someone does call bio_get() on the bio, then we flag the bio as
now having valid count and that we must properly honor the reference
count when it's being put.
Tested-by: Robert Elliott <elliott@hp.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>
Pull crypto fixes from Herbert Xu:
"This fixes a build problem with bcm63xx and yet another fix to the
memzero_explicit function to ensure that the memset is not elided"
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
hwrng: bcm63xx - Fix driver compilation
lib: make memzero_explicit more robust against dead store elimination
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=gmuD
-----END PGP SIGNATURE-----
Merge tag 'media/v4.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media fixes from Mauro Carvalho Chehab:
"Three driver fixes:
- fix for omap4, fixing a regression due to a subsystem API that got
removed for 4.1 (commit efde234674);
- fix for one of the formats supported by Marvel ccic driver;
- fix rcar_vin driver that, when stopping abnormally, the driver
can't return from wait_for_completion"
* tag 'media/v4.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
[media] v4l: omap4iss: Replace outdated OMAP4 control pad API with syscon
[media] media: soc_camera: rcar_vin: Fix wait_for_completion
[media] marvell-ccic: fix Y'CbCr ordering
In commit 0b053c9518 ("lib: memzero_explicit: use barrier instead
of OPTIMIZER_HIDE_VAR"), we made memzero_explicit() more robust in
case LTO would decide to inline memzero_explicit() and eventually
find out it could be elimiated as dead store.
While using barrier() works well for the case of gcc, recent efforts
from LLVMLinux people suggest to use llvm as an alternative to gcc,
and there, Stephan found in a simple stand-alone user space example
that llvm could nevertheless optimize and thus elimitate the memset().
A similar issue has been observed in the referenced llvm bug report,
which is regarded as not-a-bug.
Based on some experiments, icc is a bit special on its own, while it
doesn't seem to eliminate the memset(), it could do so with an own
implementation, and then result in similar findings as with llvm.
The fix in this patch now works for all three compilers (also tested
with more aggressive optimization levels). Arguably, in the current
kernel tree it's more of a theoretical issue, but imho, it's better
to be pedantic about it.
It's clearly visible with gcc/llvm though, with the below code: if we
would have used barrier() only here, llvm would have omitted clearing,
not so with barrier_data() variant:
static inline void memzero_explicit(void *s, size_t count)
{
memset(s, 0, count);
barrier_data(s);
}
int main(void)
{
char buff[20];
memzero_explicit(buff, sizeof(buff));
return 0;
}
$ gcc -O2 test.c
$ gdb a.out
(gdb) disassemble main
Dump of assembler code for function main:
0x0000000000400400 <+0>: lea -0x28(%rsp),%rax
0x0000000000400405 <+5>: movq $0x0,-0x28(%rsp)
0x000000000040040e <+14>: movq $0x0,-0x20(%rsp)
0x0000000000400417 <+23>: movl $0x0,-0x18(%rsp)
0x000000000040041f <+31>: xor %eax,%eax
0x0000000000400421 <+33>: retq
End of assembler dump.
$ clang -O2 test.c
$ gdb a.out
(gdb) disassemble main
Dump of assembler code for function main:
0x00000000004004f0 <+0>: xorps %xmm0,%xmm0
0x00000000004004f3 <+3>: movaps %xmm0,-0x18(%rsp)
0x00000000004004f8 <+8>: movl $0x0,-0x8(%rsp)
0x0000000000400500 <+16>: lea -0x18(%rsp),%rax
0x0000000000400505 <+21>: xor %eax,%eax
0x0000000000400507 <+23>: retq
End of assembler dump.
As gcc, clang, but also icc defines __GNUC__, it's sufficient to define
this in compiler-gcc.h only to be picked up. For a fallback or otherwise
unsupported compiler, we define it as a barrier. Similarly, for ecc which
does not support gcc inline asm.
Reference: https://llvm.org/bugs/show_bug.cgi?id=15495
Reported-by: Stephan Mueller <smueller@chronox.de>
Tested-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Stephan Mueller <smueller@chronox.de>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: mancha security <mancha1@zoho.com>
Cc: Mark Charlebois <charlebm@gmail.com>
Cc: Behan Webster <behanw@converseincode.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
for ext4 encryption which provide better security and performance.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
iQEcBAABCAAGBQJVRsVDAAoJEPL5WVaVDYGj/UUIAI6zLGhq3I8uQLZQC22Ew2Ph
TPj6eABDuTrB/7QpAu21Dk59N70MQpsBTES6yLWWLf/eHp0gsH7gCNY/C9185vOh
tQjzw18hRH2IfPftOBrjDlPGbbBD8Gu9jAmpm5kKKOtBuSVbKQ4GeN6BTECkgwlg
U5EJHJJ5Ahl4MalODFreOE5ZrVC7FWGEpc1y/MquQ0qcGSGlNd35leK5FE2bfHWZ
M1IJfXH5RRVPUBp26uNvzEg0TtpqkigmCJUT6gOVLfSYBw+lYEbGl4lCflrJmbgt
8EZh3Q0plsDbNhMzqSvOE4RvsOZ28oMjRNbzxkAaoz/FlatWX2hrfAoI2nqRrKg=
=Unbp
-----END PGP SIGNATURE-----
Merge tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"Some miscellaneous bug fixes and some final on-disk and ABI changes
for ext4 encryption which provide better security and performance"
* tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix growing of tiny filesystems
ext4: move check under lock scope to close a race.
ext4: fix data corruption caused by unwritten and delayed extents
ext4 crypto: remove duplicated encryption mode definitions
ext4 crypto: do not select from EXT4_FS_ENCRYPTION
ext4 crypto: add padding to filenames before encrypting
ext4 crypto: simplify and speed up filename encryption
Pull drm fixes from Dave Airlie:
"One intel fix, one rockchip fix, and a bunch of radeon fixes for some
regressions from audio rework and vm stability"
* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
drm/i915/chv: Implement WaDisableShadowRegForCpd
drm/radeon: fix userptr return value checking (v2)
drm/radeon: check new address before removing old one
drm/radeon: reset BOs address after clearing it.
drm/radeon: fix lockup when BOs aren't part of the VM on release
drm/radeon: add SI DPM quirk for Sapphire R9 270 Dual-X 2G GDDR5
drm/radeon: adjust pll when audio is not enabled
drm/radeon: only enable audio streams if the monitor supports it
drm/radeon: only mark audio as connected if the monitor supports it (v3)
drm/radeon/audio: don't enable packets until the end
drm/radeon: drop dce6_dp_enable
drm/radeon: fix ordering of AVI packet setup
drm/radeon: Use drm_calloc_ab for CS relocs
drm/rockchip: fix error check when getting irq
MAINTAINERS: add entry for Rockchip drm drivers
Just a single intel fix
* tag 'drm-intel-fixes-2015-04-30' of git://anongit.freedesktop.org/drm-intel:
drm/i915/chv: Implement WaDisableShadowRegForCpd
one fix and maintainers update
* 'drm-next0420' of https://github.com/markyzq/kernel-drm-rockchip:
drm/rockchip: fix error check when getting irq
MAINTAINERS: add entry for Rockchip drm drivers
This is three logical fixes (as 5 patches). The 3ware class of drivers were
causing an oops with multiqueue by tearing down the command mappings after
completing the command (where the variables in the command used to tear down
the mapping were no-longer valid). There's also a fix for the qnap iscsi
target which was choking on us sending it commands that were too long and a
fix for the reworked aha1542 allocating GFP_KERNEL under a lock.
Signed-off-by: James Bottomley <JBottomley@Odin.com>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
iQEcBAABAgAGBQJVRkgEAAoJEDeqqVYsXL0MZbEIAL7Repky0TI1GvyYVpbJLSc+
SlJurEQ9DIpsnNtHJlEfLHicqsrK3v/xS+3Kopd1OUEIjQ0kTFPkenTiJbwFNIB+
l7D3V1EfEdnOki7F8KU5bFf3i4KWeEUZ4v/FR3PC7dz4cFRav7OrMoGaA36yT/ns
I4NFZ7iOa/6QXzfrywTDU5HbHgQYIN2MfCPy/NrVP95Yq09TkN5ulXDz/h6PD6Iy
GV/RmeckUqkdO5SZq9kkIgR/czLpVCaqpf3/G6lFdfunNkhQJ96lQTzYwbvtPBrJ
m6+sxrcCWlHzIkJsXrKtopPYzSzGdApLSsZjuYtP3RJD0uO9psfgW8pbls3dDCg=
=n4aD
-----END PGP SIGNATURE-----
Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"This is three logical fixes (as 5 patches).
The 3ware class of drivers were causing an oops with multiqueue by
tearing down the command mappings after completing the command (where
the variables in the command used to tear down the mapping were
no-longer valid). There's also a fix for the qnap iscsi target which
was choking on us sending it commands that were too long and a fix for
the reworked aha1542 allocating GFP_KERNEL under a lock"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
3w-9xxx: fix command completion race
3w-xxxx: fix command completion race
3w-sas: fix command completion race
aha1542: Allocate memory before taking a lock
SCSI: add 1024 max sectors black list flag
Pull slave dmaengine fixes from Vinod Koul:
"Here are the fixes in dmaengine subsystem for rc2:
- privatecnt fix for slave dma request API by Christopher
- warn fix for PM ifdef in usb-dmac by Geert
- fix hardware dependency for xgene by Jean"
* 'next' of git://git.infradead.org/users/vkoul/slave-dma:
dmaengine: increment privatecnt when using dma_get_any_slave_channel
dmaengine: xgene: Set hardware dependency
dmaengine: usb-dmac: Protect PM-only functions to kill warning
- Build fix for SMP=n in book3s_xics.c
- Fix for Daniel's pci_controller_ops on powernv.
- Revert the TM syscall abort patch for now.
- CPU affinity fix from Nathan.
- Two EEH fixes from Gavin.
- Fix for CR corruption from Sam.
- Selftest build fix.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1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=S0WU
-----END PGP SIGNATURE-----
Merge tag 'powerpc-4.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux
Pull powerpc fixes from Michael Ellerman:
- build fix for SMP=n in book3s_xics.c
- fix for Daniel's pci_controller_ops on powernv.
- revert the TM syscall abort patch for now.
- CPU affinity fix from Nathan.
- two EEH fixes from Gavin.
- fix for CR corruption from Sam.
- selftest build fix.
* tag 'powerpc-4.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
powerpc/powernv: Restore non-volatile CRs after nap
powerpc/eeh: Delay probing EEH device during hotplug
powerpc/eeh: Fix race condition in pcibios_set_pcie_reset_state()
powerpc/pseries: Correct cpu affinity for dlpar added cpus
selftests/powerpc: Fix the pmu install rule
Revert "powerpc/tm: Abort syscalls in active transactions"
powerpc/powernv: Fix early pci_controller_ops loading.
powerpc/kvm: Fix SMP=n build error in book3s_xics.c
The estimate of necessary transaction credits in ext4_flex_group_add()
is too pessimistic. It reserves credit for sb, resize inode, and resize
inode dindirect block for each group added in a flex group although they
are always the same block and thus it is enough to account them only
once. Also the number of modified GDT block is overestimated since we
fit EXT4_DESC_PER_BLOCK(sb) descriptors in one block.
Make the estimation more precise. That reduces number of requested
credits enough that we can grow 20 MB filesystem (which has 1 MB
journal, 79 reserved GDT blocks, and flex group size 16 by default).
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
fallocate() checks that the file is extent-based and returns
EOPNOTSUPP in case is not. Other tasks can convert from and to
indirect and extent so it's safe to check only after grabbing
the inode mutex.
Signed-off-by: Davide Italiano <dccitaliano@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Currently it is possible to lose whole file system block worth of data
when we hit the specific interaction with unwritten and delayed extents
in status extent tree.
The problem is that when we insert delayed extent into extent status
tree the only way to get rid of it is when we write out delayed buffer.
However there is a limitation in the extent status tree implementation
so that when inserting unwritten extent should there be even a single
delayed block the whole unwritten extent would be marked as delayed.
At this point, there is no way to get rid of the delayed extents,
because there are no delayed buffers to write out. So when a we write
into said unwritten extent we will convert it to written, but it still
remains delayed.
When we try to write into that block later ext4_da_map_blocks() will set
the buffer new and delayed and map it to invalid block which causes
the rest of the block to be zeroed loosing already written data.
For now we can fix this by simply not allowing to set delayed status on
written extent in the extent status tree. Also add WARN_ON() to make
sure that we notice if this happens in the future.
This problem can be easily reproduced by running the following xfs_io.
xfs_io -f -c "pwrite -S 0xaa 4096 2048" \
-c "falloc 0 131072" \
-c "pwrite -S 0xbb 65536 2048" \
-c "fsync" /mnt/test/fff
echo 3 > /proc/sys/vm/drop_caches
xfs_io -c "pwrite -S 0xdd 67584 2048" /mnt/test/fff
This can be theoretically also reproduced by at random by running fsx,
but it's not very reliable, though on machines with bigger page size
(like ppc) this can be seen more often (especially xfstest generic/127)
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
