Pull core block updates from Jens Axboe:
"This first core part of the block IO changes contains:
- Cleanup of the bio IO error signaling from Christoph. We used to
rely on the uptodate bit and passing around of an error, now we
store the error in the bio itself.
- Improvement of the above from myself, by shrinking the bio size
down again to fit in two cachelines on x86-64.
- Revert of the max_hw_sectors cap removal from a revision again,
from Jeff Moyer. This caused performance regressions in various
tests. Reinstate the limit, bump it to a more reasonable size
instead.
- Make /sys/block/<dev>/queue/discard_max_bytes writeable, by me.
Most devices have huge trim limits, which can cause nasty latencies
when deleting files. Enable the admin to configure the size down.
We will look into having a more sane default instead of UINT_MAX
sectors.
- Improvement of the SGP gaps logic from Keith Busch.
- Enable the block core to handle arbitrarily sized bios, which
enables a nice simplification of bio_add_page() (which is an IO hot
path). From Kent.
- Improvements to the partition io stats accounting, making it
faster. From Ming Lei.
- Also from Ming Lei, a basic fixup for overflow of the sysfs pending
file in blk-mq, as well as a fix for a blk-mq timeout race
condition.
- Ming Lin has been carrying Kents above mentioned patches forward
for a while, and testing them. Ming also did a few fixes around
that.
- Sasha Levin found and fixed a use-after-free problem introduced by
the bio->bi_error changes from Christoph.
- Small blk cgroup cleanup from Viresh Kumar"
* 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits)
blk: Fix bio_io_vec index when checking bvec gaps
block: Replace SG_GAPS with new queue limits mask
block: bump BLK_DEF_MAX_SECTORS to 2560
Revert "block: remove artifical max_hw_sectors cap"
blk-mq: fix race between timeout and freeing request
blk-mq: fix buffer overflow when reading sysfs file of 'pending'
Documentation: update notes in biovecs about arbitrarily sized bios
block: remove bio_get_nr_vecs()
fs: use helper bio_add_page() instead of open coding on bi_io_vec
block: kill merge_bvec_fn() completely
md/raid5: get rid of bio_fits_rdev()
md/raid5: split bio for chunk_aligned_read
block: remove split code in blkdev_issue_{discard,write_same}
btrfs: remove bio splitting and merge_bvec_fn() calls
bcache: remove driver private bio splitting code
block: simplify bio_add_page()
block: make generic_make_request handle arbitrarily sized bios
blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL)
block: don't access bio->bi_error after bio_put()
block: shrink struct bio down to 2 cache lines again
...
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>
For write/discard obj_requests that involved a copyup method call, the
opcode of the first op is CEPH_OSD_OP_CALL and the ->callback is
rbd_img_obj_copyup_callback(). The latter frees copyup pages, sets
->xferred and delegates to rbd_img_obj_callback(), the "normal" image
object callback, for reporting to block layer and putting refs.
rbd_osd_req_callback() however treats CEPH_OSD_OP_CALL as a trivial op,
which means obj_request is marked done in rbd_osd_trivial_callback(),
*before* ->callback is invoked and rbd_img_obj_copyup_callback() has
a chance to run. Marking obj_request done essentially means giving
rbd_img_obj_callback() a license to end it at any moment, so if another
obj_request from the same img_request is being completed concurrently,
rbd_img_obj_end_request() may very well be called on such prematurally
marked done request:
<obj_request-1/2 reply>
handle_reply()
rbd_osd_req_callback()
rbd_osd_trivial_callback()
rbd_obj_request_complete()
rbd_img_obj_copyup_callback()
rbd_img_obj_callback()
<obj_request-2/2 reply>
handle_reply()
rbd_osd_req_callback()
rbd_osd_trivial_callback()
for_each_obj_request(obj_request->img_request) {
rbd_img_obj_end_request(obj_request-1/2)
rbd_img_obj_end_request(obj_request-2/2) <--
}
Calling rbd_img_obj_end_request() on such a request leads to trouble,
in particular because its ->xfferred is 0. We report 0 to the block
layer with blk_update_request(), get back 1 for "this request has more
data in flight" and then trip on
rbd_assert(more ^ (which == img_request->obj_request_count));
with rhs (which == ...) being 1 because rbd_img_obj_end_request() has
been called for both requests and lhs (more) being 1 because we haven't
got a chance to set ->xfferred in rbd_img_obj_copyup_callback() yet.
To fix this, leverage that rbd wants to call class methods in only two
cases: one is a generic method call wrapper (obj_request is standalone)
and the other is a copyup (obj_request is part of an img_request). So
make a dedicated handler for CEPH_OSD_OP_CALL and directly invoke
rbd_img_obj_copyup_callback() from it if obj_request is part of an
img_request, similar to how CEPH_OSD_OP_READ handler invokes
rbd_img_obj_request_read_callback().
Since rbd_img_obj_copyup_callback() is now being called from the OSD
request callback (only), it is renamed to rbd_osd_copyup_callback().
Cc: Alex Elder <elder@linaro.org>
Cc: stable@vger.kernel.org # 3.10+, needs backporting for < 3.18
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Some drivers use it now, others just set the limits field manually.
But in preparation for splitting this into a hard and soft limit,
ensure that they all call the proper function for setting the hw
limit for discards.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
rbd_obj_request_create() is called on the main I/O path, so we need to
use GFP_NOIO to make sure allocation doesn't blow back on us. Not all
callers need this, but I'm still hardcoding the flag inside rather than
making it a parameter because a) this is going to stable, and b) those
callers shouldn't really use rbd_obj_request_create() and will be fixed
in the future.
More memory allocation fixes will follow.
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
nr_requests (/sys/block/rbd<id>/queue/nr_requests) is pretty much
irrelevant in blk-mq case because each driver sets its own max depth
that it can handle and that's the number of tags that gets preallocated
on setup. Users can't increase queue depth beyond that value via
writing to nr_requests.
For rbd we are happy with the default BLKDEV_MAX_RQ (128) for most
cases but we want to give users the opportunity to increase it.
Introduce a new per-device queue_depth option to do just that:
$ sudo rbd map -o queue_depth=1024 ...
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
The default queue_limits::max_segments value (BLK_MAX_SEGMENTS = 128)
unnecessarily limits bio sizes to 512k (assuming 4k pages). rbd, being
a virtual block device, doesn't have any restrictions on the number of
physical segments, so bump max_segments to max_hw_sectors, in theory
allowing a sector per segment (although the only case this matters that
I can think of is some readv/writev style thing). In practice this is
going to give us 1M bios - the number of segments in a bio is limited
in bio_get_nr_vecs() by BIO_MAX_PAGES = 256.
Note that this doesn't result in any improvement on a typical direct
sequential test. This is because on a box with a not too badly
fragmented memory the default BLK_MAX_SEGMENTS is enough to see nice
rbd object size sized requests. The only difference is the size of
bios being merged - 512k vs 1M for something like
$ dd if=/dev/zero of=/dev/rbd0 oflag=direct bs=$RBD_OBJ_SIZE
$ dd if=/dev/rbd0 iflag=direct of=/dev/null bs=$RBD_OBJ_SIZE
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
As part of unmap sequence, kernel client has to talk to the OSDs to
teardown watch on the header object. If none of the OSDs are available
it would hang forever, until interrupted by a signal - when that
happens we follow through with the rest of unmap procedure (i.e.
unregister the device and put all the data structures) and the unmap is
still considired successful (rbd cli tool exits with 0). The watch on
the userspace side should eventually timeout so that's fine.
This isn't very nice, because various userspace tools (pacemaker rbd
resource agent, for example) then have to worry about setting up their
own timeouts. Timeout it with mount_timeout (60 seconds by default).
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Sage Weil <sage@redhat.com>
There are currently three libceph-level timeouts that the user can
specify on mount: mount_timeout, osd_idle_ttl and osdkeepalive. All of
these are in seconds and no checking is done on user input: negative
values are accepted, we multiply them all by HZ which may or may not
overflow, arbitrarily large jiffies then get added together, etc.
There is also a bug in the way mount_timeout=0 is handled. It's
supposed to mean "infinite timeout", but that's not how wait.h APIs
treat it and so __ceph_open_session() for example will busy loop
without much chance of being interrupted if none of ceph-mons are
there.
Fix all this by verifying user input, storing timeouts capped by
msecs_to_jiffies() in jiffies and using the new ceph_timeout_jiffies()
helper for all user-specified waits to handle infinite timeouts
correctly.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
When we end I/O struct request with error, we need to pass
obj_request->length as @nr_bytes so that the entire obj_request worth
of bytes is completed. Otherwise block layer ends up confused and we
trip on
rbd_assert(more ^ (which == img_request->obj_request_count));
in rbd_img_obj_callback() due to more being true no matter what. We
already do it in most cases but we are missing some, in particular
those where we don't even get a chance to submit any obj_requests, due
to an early -ENOMEM for example.
A number of obj_request->xferred assignments seem to be redundant but
I haven't touched any of obj_request->xferred stuff to keep this small
and isolated.
Cc: Alex Elder <elder@linaro.org>
Cc: stable@vger.kernel.org # 3.10+
Reported-by: Shawn Edwards <lesser.evil@gmail.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Set QUEUE_FLAG_NONROT. Following commit b277da0a8a ("block: disable
entropy contributions for nonrot devices") we should also clear
QUEUE_FLAG_ADD_RANDOM, but it's off by default for blk-mq drivers, so
just note it in the comment.
Also remove physical block size assignment - no sense in repeating
defaults that are not going to change.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This converts the rbd driver to use the blk-mq infrastructure. Except
for switching to a per-request work item this is almost mechanical.
This was tested by Alexandre DERUMIER in November, and found to give
him 120000 iops, although the only comparism available was an old
3.10 kernel which gave 80000iops.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <elder@linaro.org>
[idryomov@gmail.com: context, blk_mq_init_queue() EH]
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
If the clone is resized down to 0, it becomes standalone. If such
resize is carried over while an image is mapped we would detect this
and call rbd_dev_parent_put() which means "let go of all parent state,
including the spec(s) of parent images(s)". This leads to a mismatch
between "rbd info" and sysfs parent fields, so a fix is in order.
# rbd create --image-format 2 --size 1 foo
# rbd snap create foo@snap
# rbd snap protect foo@snap
# rbd clone foo@snap bar
# DEV=$(rbd map bar)
# rbd resize --allow-shrink --size 0 bar
# rbd resize --size 1 bar
# rbd info bar | grep parent
parent: rbd/foo@snap
Before:
# cat /sys/bus/rbd/devices/0/parent
(no parent image)
After:
# cat /sys/bus/rbd/devices/0/parent
pool_id 0
pool_name rbd
image_id 10056b8b4567
image_name foo
snap_id 2
snap_name snap
overlap 0
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>
header_rwsem should be released on errors. Also remove useless
rbd_dev->mapping.size != rbd_dev->header.image_size test.
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
It's been largely superseded by dup_token() and unused for over
2 years, identified by cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
[idryomov@redhat.com: changelog]
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
This effectively reverts the last hunk of 392a9dad7e ("rbd: detect
when clone image is flattened").
The problem with parent_overlap != 0 condition is that it's possible
and completely valid to have an image with parent_overlap == 0 whose
parent state needs to be cleaned up on unmap. The next commit, which
drops the "clone image now standalone" logic, opens up another window
of opportunity to hit this, but even without it
# cat parent-ref.sh
#!/bin/bash
rbd create --image-format 2 --size 1 foo
rbd snap create foo@snap
rbd snap protect foo@snap
rbd clone foo@snap bar
rbd resize --allow-shrink --size 0 bar
rbd resize --size 1 bar
DEV=$(rbd map bar)
rbd unmap $DEV
leaves rbd_device/rbd_spec/etc and rbd_client along with ceph_client
hanging around.
My thinking behind calling rbd_dev_parent_put() unconditionally is that
there shouldn't be any requests in flight at that point in time as we
are deep into unmap sequence. Hence, even if rbd_dev_unparent() caused
by flatten is delayed by in-flight requests, it will have finished by
the time we reach rbd_dev_unprobe() caused by unmap, thus turning
unconditional rbd_dev_parent_put() into a no-op.
Fixes: http://tracker.ceph.com/issues/10352
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>
The comment for rbd_dev_parent_get() said
* We must get the reference before checking for the overlap to
* coordinate properly with zeroing the parent overlap in
* rbd_dev_v2_parent_info() when an image gets flattened. We
* drop it again if there is no overlap.
but the "drop it again if there is no overlap" part was missing from
the implementation. This lead to absurd parent_ref values for images
with parent_overlap == 0, as parent_ref was incremented for each
img_request and virtually never decremented.
Fix this by leveraging the fact that refresh path calls
rbd_dev_v2_parent_info() under header_rwsem and use it for read in
rbd_dev_parent_get(), instead of messing around with atomics. Get rid
of barriers in rbd_dev_v2_parent_info() while at it - I don't see what
they'd pair with now and I suspect we are in a pretty miserable
situation as far as proper locking goes regardless.
Cc: stable@vger.kernel.org # 3.11+
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>
CEPH_OSD_OP_DELETE is not an extent op, stop treating it as such. This
sneaked in with discard patches - it's one of the three osd ops (the
other two are CEPH_OSD_OP_TRUNCATE and CEPH_OSD_OP_ZERO) that discard
is implemented with.
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>
The functions ceph_put_snap_context() and iput() test whether their
argument is NULL and then return immediately. Thus the test around the
call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[idryomov@redhat.com: squashed rbd.c hunk, changelog]
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
When we fail to allocate page vector in rbd_obj_read_sync() we just
basically ignore the problem and continue which will result in an oops
later. Fix the problem by returning proper error.
CC: Yehuda Sadeh <yehuda@inktank.com>
CC: Sage Weil <sage@inktank.com>
CC: ceph-devel@vger.kernel.org
CC: stable@vger.kernel.org
Coverity-id: 1226882
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Using one queue per device doesn't make much sense given that our
workfn processes "devices" and not "requests". Switch to a single
workqueue for all devices.
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Need to use WQ_MEM_RECLAIM for our workqueues to prevent I/O lockups
under memory pressure - we sit on the memory reclaim path.
Cc: stable@vger.kernel.org # 3.17, needs backporting for 3.16
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Tested-by: Micha Krause <micha@krausam.de>
Reviewed-by: Sage Weil <sage@redhat.com>
max_discard_sectors must be set for the queue to support discard.
Operations implementing discard for rbd zero data, so report that.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Only allocate two osd ops for discard requests, since the
preallocation hint is only added for regular writes. Use
rbd_img_obj_request_fill() to recreate the original write or discard
osd operations, isolating that logic to one place, and change the
assert in rbd_osd_req_create_copyup() to accept discard requests as
well.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
rbd_img_request_fill() creates a ceph_osd_request and has logic for
adding the appropriate osd ops to it based on the request type and
image properties.
For layered images, the original rbd_obj_request is resent with a
copyup operation in front, using a new ceph_osd_request. The logic for
adding the original operations should be the same as when first
sending them, so move it to a helper function.
op_type only needs to be checked once, so create a helper for that as
well and call it outside the loop in rbd_img_request_fill().
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Discard requests are a form of write, so they should go through the
same process as plain write requests and trigger copy-on-write for
layered images.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Discard may try to delete an object from a non-layered image that does not exist.
If this occurs, the image already has no data in that range, so change the
result to success.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Discards take a reference to the snapshot context of an image when
they are created. This reference needs to be cleaned up when the
request is done just as it is for regular writes.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
In rbd_img_request_fill() the image size is only checked to determine
whether we can truncate an object instead of zeroing it for discard
requests. Take rbd_dev->header_rwsem while reading the image size, and
move this read into the discard check, so that non-discard ops don't
need to take the semaphore in this function.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
This patch add the discard support for rbd driver.
There are three types operation in the driver:
1. The objects would be removed if they completely contained
within the discard range.
2. The objects would be truncated if they partly contained within
the discard range, and align with their boundary.
3. Others would be zeroed.
A discard request from blkdev_issue_discard() is defined which
REQ_WRITE and REQ_DISCARD both marked and no data, so we must
check the REQ_DISCARD first when getting the request type.
This resolve:
http://tracker.ceph.com/issues/190
[ Ilya Dryomov: This is incomplete and somewhat buggy, see follow up
commits by Josh Durgin for refinements and fixes which weren't
folded in to preserve authorship. ]
Signed-off-by: Guangliang Zhao <lucienchao@gmail.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
It could only handle the read and write operations now,
extend it for the coming discard support.
Signed-off-by: Guangliang Zhao <lucienchao@gmail.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
It need to copyup the parent's content when layered writing,
but an entire object write would overwrite it, so skip it.
Signed-off-by: Guangliang Zhao <lucienchao@gmail.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
These fields may both change while the image is mapped if a snapshot
is created or deleted or the image is resized. They are guarded by
rbd_dev->header_rwsem, so hold that while reading them, and store a
local copy to refer to outside of the critical section. The local copy
will stay consistent since the snapshot context is reference counted,
and the mapping size is just a u64. This prevents torn loads from
giving us inconsistent values.
Move reading header.snapc into the caller of rbd_img_request_create()
so that we only need to take the semaphore once. The read-only caller,
rbd_parent_request_create() can just pass NULL for snapc, since the
snapshot context is only relevant for writes.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Trying to map an image out of a pool for which we don't have an 'x'
permission bit fails with -ERANGE from ceph_extract_encoded_string()
due to an unsigned vs signed bug. Fix it and get rid of the -EINVAL
sink, thus propagating rbd::get_id cls method errors. (I've seen
a bunch of unexplained -ERANGE reports, I bet this is it).
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Fix to return -ENOMEM from the workqueue alloc error handling
case instead of 0, as done elsewhere in this function.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
drivers/block/rbd.c: In function ‘rbd_dev_device_setup’:
drivers/block/rbd.c:5090:19: warning: format not a string literal and no format arguments [-Wformat-security]
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Now that rbd_img_request_create() is called from work functions, no
need to use GFP_ATOMIC.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
While it was never a good idea to sleep in request_fn(), commit
34c6bc2c91 ("locking/mutexes: Add extra reschedule point") made it
a *bad* idea. mutex_lock() since 3.15 may reschedule *before* putting
task on the mutex wait queue, which for tasks in !TASK_RUNNING state
means block forever. request_fn() may be called with !TASK_RUNNING on
the way to schedule() in io_schedule().
Offload request handling to a workqueue, one per rbd device, to avoid
calling blocking primitives from rbd_request_fn().
Fixes: http://tracker.ceph.com/issues/8818
Cc: stable@vger.kernel.org # 3.16, needs backporting for 3.15
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Tested-by: Eric Eastman <eric0e@aol.com>
Tested-by: Greg Wilson <greg.wilson@keepertech.com>
Reviewed-by: Alex Elder <elder@linaro.org>
If we are mapping a snapshot, we must read in the parent_overlap value
of that snapshot instead of that of the base image. Not doing so may
in particular result in us returning zeros instead of user data:
# cat overlap-snap.sh
#!/bin/bash
rbd create --size 10 --image-format 2 foo
FOO_DEV=$(rbd map foo)
dd if=/dev/urandom of=$FOO_DEV bs=1M &>/dev/null
echo "Base image"
dd if=$FOO_DEV bs=1 count=16 skip=$(((4 << 20) - 8)) 2>/dev/null | xxd
rbd snap create foo@snap
rbd snap protect foo@snap
rbd clone foo@snap bar
rbd snap create bar@snap
BAR_DEV=$(rbd map bar@snap)
echo "Snapshot"
dd if=$BAR_DEV bs=1 count=16 skip=$(((4 << 20) - 8)) 2>/dev/null | xxd
rbd resize --allow-shrink --size 4 bar
echo "Snapshot after base image resize"
dd if=$BAR_DEV bs=1 count=16 skip=$(((4 << 20) - 8)) 2>/dev/null | xxd
# ./overlap-snap.sh
Base image
0000000: e781 e33b d34b 2225 6034 2845 a2e3 36ed ...;.K"%`4(E..6.
Snapshot
0000000: e781 e33b d34b 2225 6034 2845 a2e3 36ed ...;.K"%`4(E..6.
Resizing image: 100% complete...done.
Snapshot after base image resize
0000000: e781 e33b d34b 2225 0000 0000 0000 0000 ...;.K"%........
Even though bar@snap is taken with the old bar parent_overlap (8M),
reads from bar@snap beyond the new bar parent_overlap (4M) return
zeroes. Fix it.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Currently rbd_dev_v2_header_info() reads in parent info before the snap
context is read in. This is wrong, because we may need to look at the
the parent_overlap value of the snapshot instead of that of the base
image, for example when mapping a snapshot - see next commit. (When
mapping a snapshot, all we got is its name and we need the snap context
to translate that name into an id to know which parent info to look
for.)
The approach taken here is to make sure rbd_dev_v2_parent_info() is
called after the snap context has been read in. The other approach
would be to add a parent_overlap field to struct rbd_mapping and
maintain it the same way rbd_mapping::size is maintained. The reason
I chose the first approach is that the value of keeping around both
base image values and the actual mapping values is unclear to me.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
There is no sense in trying to update the mapping size before it's even
been set.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Recently discovered watch/notify problems showed that we really can't
ignore errors in anything refresh related. Alas, currently there is
not much we can do in response to those errors, except print warnings.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
rbd_dev_spec_update() has two modes of operation, with nothing in
common between them. Split it into two functions, one for each mode
and make our expectations more clear.
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
