Mostly for historical reasons, q->blk_trace is assigned through xchg()
and cmpxchg() atomic operations. Although this is correct, sparse
complains about this because it violates rcu annotations since commit
c780e86dd4 ("blktrace: Protect q->blk_trace with RCU") which started
to use rcu for accessing q->blk_trace. Furthermore there's no real need
for atomic operations anymore since all changes to q->blk_trace happen
under q->blk_trace_mutex and since it also makes more sense to check if
q->blk_trace is set with the mutex held earlier.
So let's just replace xchg() with rcu_replace_pointer() and cmpxchg()
with explicit check and rcu_assign_pointer(). This makes the code more
efficient and sparse happy.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We use one blktrace per request_queue, that means one per the entire
disk. So we cannot run one blktrace on say /dev/vda and then /dev/vda1,
or just two calls on /dev/vda.
We check for concurrent setup only at the very end of the blktrace setup though.
If we try to run two concurrent blktraces on the same block device the
second one will fail, and the first one seems to go on. However when
one tries to kill the first one one will see things like this:
The kernel will show these:
```
debugfs: File 'dropped' in directory 'nvme1n1' already present!
debugfs: File 'msg' in directory 'nvme1n1' already present!
debugfs: File 'trace0' in directory 'nvme1n1' already present!
``
And userspace just sees this error message for the second call:
```
blktrace /dev/nvme1n1
BLKTRACESETUP(2) /dev/nvme1n1 failed: 5/Input/output error
```
The first userspace process #1 will also claim that the files
were taken underneath their nose as well. The files are taken
away form the first process given that when the second blktrace
fails, it will follow up with a BLKTRACESTOP and BLKTRACETEARDOWN.
This means that even if go-happy process #1 is waiting for blktrace
data, we *have* been asked to take teardown the blktrace.
This can easily be reproduced with break-blktrace [0] run_0005.sh test.
Just break out early if we know we're already going to fail, this will
prevent trying to create the files all over again, which we know still
exist.
[0] https://github.com/mcgrof/break-blktrace
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The function blk_log_remap() can be simplified by removing the
call to get_pdu_remap() that copies the values into extra variable to
print the data, which also fixes the endiannness warning reported by
sparse.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In function get_pdu_len() replace variable type from __u64 to
__be64. This fixes sparse warning.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In blk_add_trace_spliti() blk_add_trace_bio_remap() use
blk_status_to_errno() to pass the error instead of pasing the bi_status.
This fixes the sparse warning.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The status can be trivially derived from the bio itself. That also avoid
callers like NVMe to incorrectly pass a blk_status_t instead of the errno,
and the overhead of translating the blk_status_t to the errno in the I/O
completion fast path when no tracing is enabled.
Fixes: 35fe0d12c8 ("nvme: trace bio completion")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently informational messages within block trace do not have PID
information of the process reporting the message included. With BFQ it
is sometimes useful to have the information and there's no good reason
to omit the information from the trace. So just fill in pid information
when generating note message.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There was a recent change in blktrace.c that added a RCU protection to
`q->blk_trace` in order to fix a use-after-free issue during access.
However the change missed an edge case that can lead to dereferencing of
`bt` pointer even when it's NULL:
Coverity static analyzer marked this as a FORWARD_NULL issue with CID
1460458.
```
/kernel/trace/blktrace.c: 1904 in sysfs_blk_trace_attr_store()
1898 ret = 0;
1899 if (bt == NULL)
1900 ret = blk_trace_setup_queue(q, bdev);
1901
1902 if (ret == 0) {
1903 if (attr == &dev_attr_act_mask)
>>> CID 1460458: Null pointer dereferences (FORWARD_NULL)
>>> Dereferencing null pointer "bt".
1904 bt->act_mask = value;
1905 else if (attr == &dev_attr_pid)
1906 bt->pid = value;
1907 else if (attr == &dev_attr_start_lba)
1908 bt->start_lba = value;
1909 else if (attr == &dev_attr_end_lba)
```
Added a reassignment with RCU annotation to fix the issue.
Fixes: c780e86dd4 ("blktrace: Protect q->blk_trace with RCU")
Cc: stable@vger.kernel.org
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Cengiz Can <cengiz@kernel.wtf>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
KASAN is reporting that __blk_add_trace() has a use-after-free issue
when accessing q->blk_trace. Indeed the switching of block tracing (and
thus eventual freeing of q->blk_trace) is completely unsynchronized with
the currently running tracing and thus it can happen that the blk_trace
structure is being freed just while __blk_add_trace() works on it.
Protect accesses to q->blk_trace by RCU during tracing and make sure we
wait for the end of RCU grace period when shutting down tracing. Luckily
that is rare enough event that we can afford that. Note that postponing
the freeing of blk_trace to an RCU callback should better be avoided as
it could have unexpected user visible side-effects as debugfs files
would be still existing for a short while block tracing has been shut
down.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=205711
CC: stable@vger.kernel.org
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reported-by: Tristan Madani <tristmd@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As there's two struct ring_buffers in the kernel, it causes some confusion.
The other one being the perf ring buffer. It was agreed upon that as neither
of the ring buffers are generic enough to be used globally, they should be
renamed as:
perf's ring_buffer -> perf_buffer
ftrace's ring_buffer -> trace_buffer
This implements the changes to the ring buffer that ftrace uses.
Link: https://lore.kernel.org/r/20191213140531.116b3200@gandalf.local.home
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As we are working to remove the generic "ring_buffer" name that is used by
both tracing and perf, the ring_buffer name for tracing will be renamed to
trace_buffer, and perf's ring buffer will be renamed to perf_buffer.
As there already exists a trace_buffer that is used by the trace_arrays, it
needs to be first renamed to array_buffer.
Link: https://lore.kernel.org/r/20191213153553.GE20583@krava
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
cgroup ID is currently allocated using a dedicated per-hierarchy idr
and used internally and exposed through tracepoints and bpf. This is
confusing because there are tracepoints and other interfaces which use
the cgroupfs ino as IDs.
The preceding changes made kn->id exposed as ino as 64bit ino on
supported archs or ino+gen (low 32bits as ino, high gen). There's no
reason for cgroup to use different IDs. The kernfs IDs are unique and
userland can easily discover them and map them back to paths using
standard file operations.
This patch replaces cgroup IDs with kernfs IDs.
* cgroup_id() is added and all cgroup ID users are converted to use it.
* kernfs_node creation is moved to earlier during cgroup init so that
cgroup_id() is available during init.
* While at it, s/cgroup/cgrp/ in psi helpers for consistency.
* Fallback ID value is changed to 1 to be consistent with root cgroup
ID.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Each kernfs_node is identified with a 64bit ID. The low 32bit is
exposed as ino and the high gen. While this already allows using inos
as keys by looking up with wildcard generation number of 0, it's
adding unnecessary complications for 64bit ino archs which can
directly use kernfs_node IDs as inos to uniquely identify each cgroup
instance.
This patch exposes IDs directly as inos on 64bit ino archs. The
conversion is mostly straight-forward.
* 32bit ino archs behave the same as before. 64bit ino archs now use
the whole 64bit ID as ino and the generation number is fixed at 1.
* 64bit inos still use the same idr allocator which gurantees that the
lower 32bits identify the current live instance uniquely and the
high 32bits are incremented whenever the low bits wrap. As the
upper 32bits are no longer used as gen and we don't wanna start ino
allocation with 33rd bit set, the initial value for highbits
allocation is changed to 0 on 64bit ino archs.
* blktrace exposes two 32bit numbers - (INO,GEN) pair - to identify
the issuing cgroup. Userland builds FILEID_INO32_GEN fids from
these numbers to look up the cgroups. To remain compatible with the
behavior, always output (LOW32,HIGH32) which will be constructed
back to the original 64bit ID by __kernfs_fh_to_dentry().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
kernfs_node->id is currently a union kernfs_node_id which represents
either a 32bit (ino, gen) pair or u64 value. I can't see much value
in the usage of the union - all that's needed is a 64bit ID which the
current code is already limited to. Using a union makes the code
unnecessarily complicated and prevents using 64bit ino without adding
practical benefits.
This patch drops union kernfs_node_id and makes kernfs_node->id a u64.
ino is stored in the lower 32bits and gen upper. Accessors -
kernfs[_id]_ino() and kernfs[_id]_gen() - are added to retrieve the
ino and gen. This simplifies ID handling less cumbersome and will
allow using 64bit inos on supported archs.
This patch doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexei Starovoitov <ast@kernel.org>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-block@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is a plan to build the kernel with -Wimplicit-fallthrough and
this place in the code produced a warning (W=1).
This commit remove the following warning:
kernel/trace/blktrace.c:725:9: warning: this statement may fall through [-Wimplicit-fallthrough=]
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Prior patches ensured that any bio that interacts with a request_queue
is properly associated with a blkg. This makes bio->bi_css unnecessary
as blkg maintains a reference to blkcg already.
This removes the bio field bi_css and transfers corresponding uses to
access via bi_blkg.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Prior patches ensured that all bios are now associated with some blkg.
This now makes bio->bi_css unnecessary as blkg maintains a reference to
the blkcg already.
This patch removes the field bi_css and transfers corresponding uses to
access via bi_blkg.
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block
Pull more block updates from Jens Axboe:
- Set of bcache fixes and changes (Coly)
- The flush warn fix (me)
- Small series of BFQ fixes (Paolo)
- wbt hang fix (Ming)
- blktrace fix (Steven)
- blk-mq hardware queue count update fix (Jianchao)
- Various little fixes
* tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block: (31 commits)
block/DAC960.c: make some arrays static const, shrinks object size
blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter
blk-mq: init hctx sched after update ctx and hctx mapping
block: remove duplicate initialization
tracing/blktrace: Fix to allow setting same value
pktcdvd: fix setting of 'ret' error return for a few cases
block: change return type to bool
block, bfq: return nbytes and not zero from struct cftype .write() method
block, bfq: improve code of bfq_bfqq_charge_time
block, bfq: reduce write overcharge
block, bfq: always update the budget of an entity when needed
block, bfq: readd missing reset of parent-entity service
blk-wbt: fix IO hang in wbt_wait()
block: don't warn for flush on read-only device
bcache: add the missing comments for smp_mb()/smp_wmb()
bcache: remove unnecessary space before ioctl function pointer arguments
bcache: add missing SPDX header
bcache: move open brace at end of function definitions to next line
bcache: add static const prefix to char * array declarations
bcache: fix code comments style
...
- Restructure of lockdep and latency tracers
This is the biggest change. Joel Fernandes restructured the hooks
from irqs and preemption disabling and enabling. He got rid of
a lot of the preprocessor #ifdef mess that they caused.
He turned both lockdep and the latency tracers to use trace events
inserted in the preempt/irqs disabling paths. But unfortunately,
these started to cause issues in corner cases. Thus, parts of the
code was reverted back to where lockde and the latency tracers
just get called directly (without using the trace events).
But because the original change cleaned up the code very nicely
we kept that, as well as the trace events for preempt and irqs
disabling, but they are limited to not being called in NMIs.
- Have trace events use SRCU for "rcu idle" calls. This was required
for the preempt/irqs off trace events. But it also had to not
allow them to be called in NMI context. Waiting till Paul makes
an NMI safe SRCU API.
- New notrace SRCU API to allow trace events to use SRCU.
- Addition of mcount-nop option support
- SPDX headers replacing GPL templates.
- Various other fixes and clean ups.
- Some fixes are marked for stable, but were not fully tested
before the merge window opened.
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Merge tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Restructure of lockdep and latency tracers
This is the biggest change. Joel Fernandes restructured the hooks
from irqs and preemption disabling and enabling. He got rid of a lot
of the preprocessor #ifdef mess that they caused.
He turned both lockdep and the latency tracers to use trace events
inserted in the preempt/irqs disabling paths. But unfortunately,
these started to cause issues in corner cases. Thus, parts of the
code was reverted back to where lockdep and the latency tracers just
get called directly (without using the trace events). But because the
original change cleaned up the code very nicely we kept that, as well
as the trace events for preempt and irqs disabling, but they are
limited to not being called in NMIs.
- Have trace events use SRCU for "rcu idle" calls. This was required
for the preempt/irqs off trace events. But it also had to not allow
them to be called in NMI context. Waiting till Paul makes an NMI safe
SRCU API.
- New notrace SRCU API to allow trace events to use SRCU.
- Addition of mcount-nop option support
- SPDX headers replacing GPL templates.
- Various other fixes and clean ups.
- Some fixes are marked for stable, but were not fully tested before
the merge window opened.
* tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
tracing: Fix SPDX format headers to use C++ style comments
tracing: Add SPDX License format tags to tracing files
tracing: Add SPDX License format to bpf_trace.c
blktrace: Add SPDX License format header
s390/ftrace: Add -mfentry and -mnop-mcount support
tracing: Add -mcount-nop option support
tracing: Avoid calling cc-option -mrecord-mcount for every Makefile
tracing: Handle CC_FLAGS_FTRACE more accurately
Uprobe: Additional argument arch_uprobe to uprobe_write_opcode()
Uprobes: Simplify uprobe_register() body
tracepoints: Free early tracepoints after RCU is initialized
uprobes: Use synchronize_rcu() not synchronize_sched()
tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
ftrace: Remove unused pointer ftrace_swapper_pid
tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage"
tracing/irqsoff: Handle preempt_count for different configs
tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"
tracing: irqsoff: Account for additional preempt_disable
trace: Use rcu_dereference_raw for hooks from trace-event subsystem
tracing/kprobes: Fix within_notrace_func() to check only notrace functions
...
Masami Hiramatsu reported:
Current trace-enable attribute in sysfs returns an error
if user writes the same setting value as current one,
e.g.
# cat /sys/block/sda/trace/enable
0
# echo 0 > /sys/block/sda/trace/enable
bash: echo: write error: Invalid argument
# echo 1 > /sys/block/sda/trace/enable
# echo 1 > /sys/block/sda/trace/enable
bash: echo: write error: Device or resource busy
But this is not a preferred behavior, it should ignore
if new setting is same as current one. This fixes the
problem as below.
# cat /sys/block/sda/trace/enable
0
# echo 0 > /sys/block/sda/trace/enable
# echo 1 > /sys/block/sda/trace/enable
# echo 1 > /sys/block/sda/trace/enable
Link: http://lkml.kernel.org/r/20180816103802.08678002@gandalf.local.home
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: cd649b8bb8 ("blktrace: remove sysfs_blk_trace_enable_show/store()")
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since @blk_debugfs_root couldn't be configured dynamically, we can
save a few memory allocation if it's not there.
Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A previous commit changed the locking around registration/cleanup,
but direct callers of blk_trace_remove() were missed. This means
that if we hit the error path in setup, we will deadlock on
attempting to re-acquire the queue trace mutex.
Fixes: 1f2cac107c ("blktrace: fix unlocked access to init/start-stop/teardown")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We always pass in blk_trace_bio_get_cgid(q, bio) to blk_add_trace_bio().
Since both are readily available in the function already, kill the
argument.
Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Rewrote commit message.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
sg.c calls into the blktrace functions without holding the proper queue
mutex for doing setup, start/stop, or teardown.
Add internal unlocked variants, and export the ones that do the proper
locking.
Fixes: 6da127ad09 ("blktrace: Add blktrace ioctls to SCSI generic devices")
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The lockdep code had reported the following unsafe locking scenario:
CPU0 CPU1
---- ----
lock(s_active#228);
lock(&bdev->bd_mutex/1);
lock(s_active#228);
lock(&bdev->bd_mutex);
*** DEADLOCK ***
The deadlock may happen when one task (CPU1) is trying to delete a
partition in a block device and another task (CPU0) is accessing
tracing sysfs file (e.g. /sys/block/dm-1/trace/act_mask) in that
partition.
The s_active isn't an actual lock. It is a reference count (kn->count)
on the sysfs (kernfs) file. Removal of a sysfs file, however, require
a wait until all the references are gone. The reference count is
treated like a rwsem using lockdep instrumentation code.
The fact that a thread is in the sysfs callback method or in the
ioctl call means there is a reference to the opended sysfs or device
file. That should prevent the underlying block structure from being
removed.
Instead of using bd_mutex in the block_device structure, a new
blk_trace_mutex is now added to the request_queue structure to protect
access to the blk_trace structure.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Fix typo in patch subject line, and prune a comment detailing how
the code used to work.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This way we don't need a block_device structure to submit I/O. The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open. Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).
For the actual I/O path all that we need is the gendisk, which exists
once per block device. But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.
Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently cfq/bfq/blk-throttle output cgroup info in trace in their own
way. Now we have standard blktrace API for this, so convert them to use
it.
Note, this changes the behavior a little bit. cgroup info isn't output
by default, we only do this with 'blk_cgroup' option enabled. cgroup
info isn't output as a string by default too, we only do this with
'blk_cgname' option enabled. Also cgroup info is output in different
position of the note string. I think these behavior changes aren't a big
issue (actually we make trace data shorter which is good), since the
blktrace note is solely for debugging.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
By default we output cgroup id in blktrace. This adds an option to
display cgroup path. Since get cgroup path is a relativly heavy
operation, we don't enable it by default.
with the option enabled, blktrace will output something like this:
dd-1353 [007] d..2 293.015252: 8,0 /test/level D R 24 + 8 [dd]
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently blktrace isn't cgroup aware. blktrace prints out task name of
current context, but the task of current context isn't always in the
cgroup where the BIO comes from. We can't use task name to find out IO
cgroup. For example, Writeback BIOs always comes from flusher thread but
the BIOs are for different blk cgroups. Request could be requeued and
dispatched from completely different tasks. MD/DM are another examples.
This patch tries to fix the gap. We print out cgroup fhandle info in
blktrace. Userspace can use open_by_handle_at() syscall to find the
cgroup by fhandle. Or userspace can use name_to_handle_at() syscall to
find fhandle for a cgroup and use a BPF program to filter out blktrace
for a specific cgroup.
We add a new 'blk_cgroup' trace option for blk tracer. It's default off.
Application which doesn't know the new option isn't affected. When it's
on, we output fhandle info right after blk_io_trace with an extra bit
set in event action. So from application point of view, blktrace with
the option will output new actions.
I didn't change blk trace event yet, since I'm not sure if changing the
trace event output is an ABI issue. If not, I'll do it later.
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
sscanf is a very poor way to parse integer. For example, I input
"discard" for act_mask, it gets 0xd and completely messes up. Using
correct API to do integer parse.
This patch also makes attributes accept any base of integer.
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We may already have a directory to put the blktrace stuff in if
1. The disk uses blk-mq
2. CONFIG_BLK_DEBUG_FS is enabled
3. We are tracing the whole disk and not a partition
Instead of hardcoding this very specific case, let's use the new
debugfs_lookup(). If the directory exists, we use it, otherwise we
create one and clean it up later.
Fixes: 07e4fead45 ("blk-mq: create debugfs directory tree")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
When I added the blk-mq debugging information to debugfs, I didn't
notice that blktrace also creates a "block" directory in debugfs. Make
them use the same dentry, now created in the core block code. Based on a
patch from Jens.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This can be used to check for fs vs non-fs requests and basically
removes all knowledge of BLOCK_PC specific from the block layer,
as well as preparing for removing the cmd_type field in struct request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
A couple tweaks to the tracing code:
- trace the request size for all requests
- trace request sector and nr_sectors only for fs requests, enforced by
helpers
- drop SCSI CDB tracing - we have SCSI tracing for this and are going
to me the CDB out of the generic struct request soon.
With this the tracing code stops to know about BLOCK_PC requests entirely,
it's just FS vs passthrough requests now, where the latter includes any
driver-private requests.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields. This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.
In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.
Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits. Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Commit 288dab8a35 ("block: add a separate operation type for secure
erase") split REQ_OP_SECURE_ERASE from REQ_OP_DISCARD without considering
all the places REQ_OP_DISCARD was being used to mean either. Fix those.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 288dab8a35 ("block: add a separate operation type for secure erase")
Signed-off-by: Jens Axboe <axboe@fb.com>
Since commit 63a4cc2486, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.
No intended functional changes in this commit.
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull block driver updates from Jens Axboe:
"This branch also contains core changes. I've come to the conclusion
that from 4.9 and forward, I'll be doing just a single branch. We
often have dependencies between core and drivers, and it's hard to
always split them up appropriately without pulling core into drivers
when that happens.
That said, this contains:
- separate secure erase type for the core block layer, from
Christoph.
- set of discard fixes, from Christoph.
- bio shrinking fixes from Christoph, as a followup up to the
op/flags change in the core branch.
- map and append request fixes from Christoph.
- NVMeF (NVMe over Fabrics) code from Christoph. This is pretty
exciting!
- nvme-loop fixes from Arnd.
- removal of ->driverfs_dev from Dan, after providing a
device_add_disk() helper.
- bcache fixes from Bhaktipriya and Yijing.
- cdrom subchannel read fix from Vchannaiah.
- set of lightnvm updates from Wenwei, Matias, Johannes, and Javier.
- set of drbd updates and fixes from Fabian, Lars, and Philipp.
- mg_disk error path fix from Bart.
- user notification for failed device add for loop, from Minfei.
- NVMe in general:
+ NVMe delay quirk from Guilherme.
+ SR-IOV support and command retry limits from Keith.
+ fix for memory-less NUMA node from Masayoshi.
+ use UINT_MAX for discard sectors, from Minfei.
+ cancel IO fixes from Ming.
+ don't allocate unused major, from Neil.
+ error code fixup from Dan.
+ use constants for PSDT/FUSE from James.
+ variable init fix from Jay.
+ fabrics fixes from Ming, Sagi, and Wei.
+ various fixes"
* 'for-4.8/drivers' of git://git.kernel.dk/linux-block: (115 commits)
nvme/pci: Provide SR-IOV support
nvme: initialize variable before logical OR'ing it
block: unexport various bio mapping helpers
scsi/osd: open code blk_make_request
target: stop using blk_make_request
block: simplify and export blk_rq_append_bio
block: ensure bios return from blk_get_request are properly initialized
virtio_blk: use blk_rq_map_kern
memstick: don't allow REQ_TYPE_BLOCK_PC requests
block: shrink bio size again
block: simplify and cleanup bvec pool handling
block: get rid of bio_rw and READA
block: don't ignore -EOPNOTSUPP blkdev_issue_write_same
block: introduce BLKDEV_DISCARD_ZERO to fix zeroout
NVMe: don't allocate unused nvme_major
nvme: avoid crashes when node 0 is memoryless node.
nvme: Limit command retries
loop: Make user notify for adding loop device failed
nvme-loop: fix nvme-loop Kconfig dependencies
nvmet: fix return value check in nvmet_subsys_alloc()
...
The blktrace code stores the current time in a 32-bit word in its
user interface. This is a bad idea because 32-bit seconds overflow
at some point.
We probably have until 2106 before this one overflows, as it seems
to use an 'unsigned' variable, but we should confirm that user
space treats it the same way.
Aside from this, we want to stop using 'struct timespec' here,
so I'm adding a comment about the overflow and change the code
to use timespec64 instead to make the loss of range more obvious.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead of overloading the discard support with the REQ_SECURE flag.
Use the opportunity to rename the queue flag as well, and remove the
dead checks for this flag in the RAID 1 and RAID 10 drivers that don't
claim support for secure erase.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This adds a REQ_OP_FLUSH operation that is sent to request_fn
based drivers by the block layer's flush code, instead of
sending requests with the request->cmd_flags REQ_FLUSH bit set.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
