This prevents erroring out while adding a device when a snapshot
unrelated to the current mapping is deleted between reading the
snapshot context and reading the snapshot names. If the mapped
snapshot name is not found an error still occurs as usual.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Removing a device deallocates the disk, unschedules the watch, and
finally cleans up the rbd_dev structure. rbd_dev_refresh(), called
from the watch callback, updates the disk size and rbd_dev
structure. With no locking between them, rbd_dev_refresh() may use the
device or rbd_dev after they've been freed.
To fix this, check whether RBD_DEV_FLAG_REMOVING is set before
updating the disk size in rbd_dev_refresh(). In order to prevent a
race where rbd_dev_refresh() is already revalidating the disk when
rbd_remove() is called, move the call to rbd_bus_del_dev() after the
watch is unregistered and all notifies are complete. It's safe to
defer deleting this structure because no new requests can be submitted
once the RBD_DEV_FLAG_REMOVING is set, since the device cannot be
opened.
Fixes: http://tracker.ceph.com/issues/5636
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
The only user of rbd_obj_notify_ack() is rbd_watch_cb(). It used
asynchronously with no tracking of when the notify ack completes, so
it may still be in progress when the osd_client is shut down. This
results in a BUG() since the osd client assumes no requests are in
flight when it stops. Since all notifies are flushed before the
osd_client is stopped, waiting for the notify ack to complete before
returning from the watch callback ensures there are no notify acks in
flight during shutdown.
Rename rbd_obj_notify_ack() to rbd_obj_notify_ack_sync() to reflect
its new synchronous nature.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
To ensure rbd_dev is not used after it's released, flush all pending
notify callbacks before calling rbd_dev_image_release(). No new
notifies can be added to the queue at this point because the watch has
already be unregistered with the osd_client.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
The order parameter is sometimes NULL in _rbd_dev_v2_snap_size(), but
the dout() always derefences it. Move this to another dout() protected
by a check that order is non-NULL.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <alex.elder@linaro.org>
rbd_osd_req_create() needs to know the snapshot context size to create
a buffer large enough to send it with the message front. It gets this
from the img_request, which was not set for the obj_request yet. This
resulted in trying to write past the end of the front payload, hitting
this BUG:
libceph: BUG_ON(p > msg->front.iov_base + msg->front.iov_len);
Fix this by associating the obj_request with its img_request
immediately after it's created, before the osd request is created.
Fixes: http://tracker.ceph.com/issues/5760
Suggested-by: Alex Elder <alex.elder@linaro.org>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <alex.elder@linaro.org>
When a request returns an error, the driver needs to report the entire
extent of the request as completed. Writes already did this, since
they always set xferred = length, but reads were skipping that step if
an error other than -ENOENT occurred. Instead, rbd would end up
passing 0 xferred to blk_end_request(), which would always report
needing more data. This resulted in an assert failing when more data
was required by the block layer, but all the object requests were
done:
[ 1868.719077] rbd: obj_request read result -108 xferred 0
[ 1868.719077]
[ 1868.719518] end_request: I/O error, dev rbd1, sector 0
[ 1868.719739]
[ 1868.719739] Assertion failure in rbd_img_obj_callback() at line 1736:
[ 1868.719739]
[ 1868.719739] rbd_assert(more ^ (which == img_request->obj_request_count));
Without this assert, reads that hit errors would hang forever, since
the block layer considered them incomplete.
Fixes: http://tracker.ceph.com/issues/5647
CC: stable@vger.kernel.org # v3.10
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <alex.elder@linaro.org>
The local variables such as 'bio_list', and 'pages' are pointers;
thus, use NULL instead of 0 to fix the following sparse warnings.
drivers/block/rbd.c:2166:32: warning: Using plain integer as NULL pointer
drivers/block/rbd.c:2168:31: warning: Using plain integer as NULL pointer
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Sage Weil <sage@inktank.com>
gcc isn't quite smart enough and generates these warnings:
drivers/block/rbd.c: In function 'rbd_img_request_fill':
drivers/block/rbd.c:1266:22: warning: 'bio_list' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/block/rbd.c:2186:14: note: 'bio_list' was declared here
drivers/block/rbd.c:2247:10: warning: 'pages' may be used uninitialized in this function [-Wmaybe-uninitialized]
even though they are initialized for their respective code paths.
Signed-off-by: Sage Weil <sage@inktank.com>
Updating an image header needs to be protected to ensure it's
done consistently. However distinct headers can be updated
concurrently without a problem. Instead of using the global
control lock to serialize headder updates, just rely on the header
semaphore. (It's already used, this just moves it out to cover
a broader section of the code.)
That leaves the control mutex protecting only the creation of rbd
clients, so rename it.
This resolves:
http://tracker.ceph.com/issues/5222
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When an rbd device is first getting mapped, its device registration
is protected the control mutex. There is no need to do that though,
because the device has already been assigned an id that's guaranteed
to be unique.
An unmap of an rbd device won't proceed if the device has a non-zero
open count or is already being unmapped. So there's no need to hold
the control mutex in that case either.
Finally, an rbd device can't be opened if it is being removed, and
it won't go away if there is a non-zero open count. So here too
there's no need to hold the control mutex while getting or putting a
reference to an rbd device's Linux device structure.
Drop the mutex calls in these cases.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Make sure two concurrent unmap operations on the same rbd device
won't collide, by only proceeding with the removal and cleanup of a
device if is not already underway.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When unmapping a device, its id is supplied, and that is used to
look up which rbd device should be unmapped. Looking up the
device involves searching the rbd device list while holding
a spinlock that protects access to that list.
Currently all of this is done under protection of the control lock,
but that protection is going away soon. To ensure the rbd_dev is
still valid (still on the list) while setting its REMOVING flag, do
so while still holding the list lock. To do so, get rid of
__rbd_get_dev(), and open code what it did in the one place it
was used.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
If more than one rbd image has the same ceph cluster configuration
(same options, same set of monitors, same keys) they normally share
a single rbd client.
When an image is getting mapped, rbd looks to see if an existing
client can be used, and creates a new one if not.
The lookup and creation are not done under a common lock though, so
mapping two images concurrently could lead to duplicate clients
getting set up needlessly. This isn't a major problem, but it's
wasteful and different from what's intended.
This patch fixes that by using the control mutex to protect
both the lookup and (if needed) creation of the client. It
was previously used just when creating.
This resolves:
http://tracker.ceph.com/issues/3094
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This includes a few relatively small fixes I found while examining
the code that refreshes image information.
This resolves:
http://tracker.ceph.com/issues/5040
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Neither zero_bio_chain() nor zero_pages() contains a call to flush
caches after zeroing a portion of a page. This can cause problems
on architectures that have caches that allow virtual address
aliasing.
This resolves:
http://tracker.ceph.com/issues/4777
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The reference to the original request dropped at the end of
rbd_img_obj_exists_callback() corresponds to the reference taken
in rbd_img_obj_exists_submit() to account for the stat request
referring to it. Move the put of that reference up right after
clearing that pointer to make its purpose more obvious.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
drivers/block/rbd.c: In function ‘zero_pages’:
drivers/block/rbd.c:1102: warning: comparison of distinct pointer types lacks a cast
Remove the hackish casts and use min_t() to fix this.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Alex Elder <elder@inktank.com>
Pull Ceph fix from Sage Weil:
"This is a recently spotted regression in the snapshot behavior...
It turns out several tests weren't being run in the nightlies so this
took a while to spot"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
rbd: send snapshot context with writes
Sending the right snapshot context with each write is required for
snapshots to work. Due to the ordering of calls, the snapshot context
is never set for any requests. This causes writes to the current
version of the image to be reflected in all snapshots, which are
supposed to be read-only.
This happens because rbd_osd_req_format_write() sets the snapshot
context based on obj_request->img_request. At this point, however,
obj_request->img_request has not been set yet, to the snapshot context
is set to NULL. Fix this by moving rbd_img_obj_request_add(), which
sets obj_request->img_request, before the osd request formatting
calls.
This resolves:
http://tracker.ceph.com/issues/5465
Reported-by: Karol Jurak <karol.jurak@gmail.com>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Pull Ceph fix from Sage Weil:
"This fixes another problem with using v2 images on 3.10 due to the
order in which fields are read from the image header.
Hopefully this is the last one"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
rbd: fetch object order before using it
rbd_dev_v2_header_onetime() fetches striping information, and
checks whether the image can be read by compariing the stripe unit
to the object size. It determines the object size by shifting
the object order, which is 0 at this point since it has not been
read yet. Move the call to get the image size and object order
before rbd_dev_v2_header_onetime() so it is set before use.
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Pull Ceph fix from Sage Weil:
"This fixes a problem preventing the kernel and userland librbd
libraries from sharing data with the new format 2 images"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
rbd: use the correct length for format 2 object names
Format 2 objects use 16 characters for the object name suffix to be
able to express the full 64-bit range of object numbers. Format 1
images only use 12 characters for this. Using 12-character names for
format 2 caused userspace and kernel rbd clients to read differently
named objects, which made an image written by one client look empty to
the other client.
CC: stable@vger.kernel.org # 3.9+
Reported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Pull ceph fixes from Sage Weil:
"There is a pair of fixes for double-frees in the recent bundle for
3.10, a couple of fixes for long-standing bugs (sleep while atomic and
an endianness fix), and a locking fix that can be triggered when osds
are going down"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
rbd: fix cleanup in rbd_add()
rbd: don't destroy ceph_opts in rbd_add()
ceph: ceph_pagelist_append might sleep while atomic
ceph: add cpu_to_le32() calls when encoding a reconnect capability
libceph: must hold mutex for reset_changed_osds()
Bjorn Helgaas pointed out that a recent commit introduced a
use-after-free condition in an error path for rbd_add().
He correctly stated:
I think b536f69a3a "rbd: set up devices only for mapped images"
introduced a use-after-free error in rbd_add():
...
If rbd_dev_device_setup() returns an error, we call
rbd_dev_image_release(), which ultimately kfrees rbd_dev.
Then we call rbd_dev_destroy(), which references fields in
the already-freed rbd_dev struct before kfreeing it again.
The simple fix is to return the error code after the call to
rbd_dev_image_release().
Closer examination revealed that there's no need to clean up
rbd_opts in that function, so fix that too.
Update some other comments that have also become out of date.
Reported-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Whether rbd_client_create() successfully creates a new client or
not, it takes responsibility for getting the ceph_opts structure
it's passed destroyed. If successful, the structure becomes
associated with the created client; if not, rbd_client_create()
will destroy it.
Previously, rbd_get_client() would call ceph_destroy_options()
if rbd_get_client() failed, and that meant it got called twice.
That led freeing various pointers more than once, which is never a
good idea.
This resolves:
http://tracker.ceph.com/issues/4559
Cc: stable@vger.kernel.org # 3.8+
Reported-by: Dan van der Ster <dan@vanderster.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Pull Ceph fixes from Sage Weil:
"Yes, this is a much larger pull than I would like after -rc1. There
are a few things included:
- a few fixes for leaks and incorrect assertions
- a few patches fixing behavior when mapped images are resized
- handling for cloned/layered images that are flattened out from
underneath the client
The last bit was non-trivial, and there is some code movement and
associated cleanup mixed in. This was ready and was meant to go in
last week but I missed the boat on Friday. My only excuse is that I
was waiting for an all clear from the testing and there were many
other shiny things to distract me.
Strictly speaking, handling the flatten case isn't a regression and
could wait, so if you like we can try to pull the series apart, but
Alex and I would much prefer to have it all in as it is a case real
users will hit with 3.10."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (33 commits)
rbd: re-submit flattened write request (part 2)
rbd: re-submit write request for flattened clone
rbd: re-submit read request for flattened clone
rbd: detect when clone image is flattened
rbd: reference count parent requests
rbd: define parent image request routines
rbd: define rbd_dev_unparent()
rbd: don't release write request until necessary
rbd: get parent info on refresh
rbd: ignore zero-overlap parent
rbd: support reading parent page data for writes
rbd: fix parent request size assumption
libceph: init sent and completed when starting
rbd: kill rbd_img_request_get()
rbd: only set up watch for mapped images
rbd: set mapping read-only flag in rbd_add()
rbd: support reading parent page data
rbd: fix an incorrect assertion condition
rbd: define rbd_dev_v2_header_info()
rbd: get rid of trivial v1 header wrappers
...
Add code to rbd_img_obj_exists_callback() to detect when a clone's
parent image has disappeared, and re-submit the original write
request in that case.
Kill off some redundant assertions.
This completes the resolution for:
http://tracker.ceph.com/issues/3763
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Add code to rbd_img_parent_read_full_callback() to detect when a
clone's parent image has disappeared, and re-submit the original
write request in that case. (See the previous commit for more
reasoning about why this is appropriate.)
Rename some variables in rbd_img_obj_parent_read_full_callback()
to match the convention used in the previous patch.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
If a clone image gets flattened while a parent read request is
underway, the original rbd object request needs to be resubmitted.
The reason is that by the time we get the response to the parent
read request, the data read from the parent may be out of date.
In other words, we could see this sequence of events:
rbd client parent image/osd
---------- ----------------
original object ENOENT;
issue parent read
respond to parent read
child image flattened
original image header refresh
<--- original object written independently here
parent read response received
Add code to rbd_img_parent_read_callback() to detect when a clone's
parent image has disappeared (as evidenced by its parent overlap
becoming 0), and re-submit the original read request in that case.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
A format 2 clone image can be the subject of a "flatten" operation,
during which all of its data gets "copied up" from its parent image,
leaving the image fully populated. Once this is complete, the
clone's association with the parent is abolished.
Since this can occur when a clone is mapped, we need to detect when
it has occurred and handle it accordingly. We know an image has
been flattened when we know it at one time had a parent, but we have
learned (via a "get_parent" object class method call) it no longer
has one.
There might be in-flight requests at the point we learn an image has
been flattened, so we can't simply clean up parent data structures
right away. Instead, we'll drop the initial parent reference when
the parent has disappeared (rather than when the image gets
destroyed), which will allow the last in-flight reference to clean
things up when it's complete.
We leverage the fact that a zero parent overlap renders an image
effectively unlayered. We set the overlap to 0 at the point we
detect the clone image has flattened, which allows the unlayered
behavior to take effect immediately, while keeping other parent
structures in place until in-flight requests to complete.
This and the next few patches resolve:
http://tracker.ceph.com/issues/3763
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Keep a reference count for uses of the parent information for an rbd
device.
An initial reference is set in rbd_img_request_create() if the
target image has a parent (with non-zero overlap). Each image
request for an image with a non-zero parent overlap gets another
reference when it's created, and that reference is dropped when the
request is destroyed.
The initial reference is dropped when the image gets torn down.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define rbd_parent_request_create() and rbd_parent_request_destroy()
to handle the creation of parent image requests submitted for
layered image objects. For simplicity, let rbd_img_request_put()
handle dropping the reference to any image request (parent or not),
and call whichever destructor is appropriate on the last put.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define rbd_dev_unparent() to encapsulate cleaning up parent data
structures from a layered rbd image.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Previously when a layered write was going to involve a copyup
request, the original osd request was released before submitting the
parent full-object read. The osd request for the copyup would then
be allocated in rbd_img_obj_parent_read_full_callback().
Shortly we will be handling the event of mapped layered images
getting flattened, and when that occurs we need to resubmit the
original request. We therefore don't want to release the osd
request until we really konw we're going to replace it--in the
callback function.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Get parent info for format 2 images on every refresh (rather than
just during the initial probe). This will be needed to detect the
disappearance of the parent image in the event a mapped image
becomes unlayered (i.e., flattened). Avoid leaking the previous
parent spec on the second and subsequent times this information is
requested by dropping the previous one (if any) before updating it.
(Also, extract the pool id into a local variable before assigning
it into the parent spec.)
Switch to using a non-zero parent overlap value rather than the
existence of a parent (a non-null parent_spec pointer) to determine
whether to mark a request layered. It will soon be possible for
a layered image to become unlayered while a request is in flight.
This means that the layered flag for an image request indicates that
there was a non-zero parent overlap at the time the image request
was created. The parent overlap can change thereafter, which may
lead to special handling at request submission or completion time.
This and the next several patches are related to:
http://tracker.ceph.com/issues/3763
NOTE:
If an error occurs while refreshing the parent info (i.e.,
requesting it after initial probe), the old parent info will
persist. This is not really correct, and is a scenario that needs
to be addressed. For now we'll assert that the failure mode is
unlikely, but the issue has been documented in tracker issue 5040.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An rbd clone image that has an overlap with its parent of 0 is
effectively not a layered image at all. Detect this case and treat
such an image as non-layered. Issue a warning to be sure the user
knows what's going on.
This resolves:
http://tracker.ceph.com/issues/5028
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Currently, rbd_img_obj_parent_read_full() assumes the incoming
object request contains bio data. But if a layered image is part of
a multi-layer stack of images it will result in read requests of
page data to parent images.
This is handling the same kind of issue as was resolved by this
commit:
5b2ab72d rbd: support reading parent page data
This resolves:
http://tracker.ceph.com/issues/5027
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The code that reads object data from the parent for a copyup on
write request currently assumes that the size of that request is the
size of a "full" object from the original target image.
That is not necessarily the case. The parent overlap could reduce
the request size below that. To fix that assumption we need to
record the number of pages in the copyup_pages array, for both an
image request and an object request. Rename a local variable in
rbd_img_obj_parent_read_full_callback() to reflect we're recording
the length of the parent read request, not the size of the target
object.
This resolves:
http://tracker.ceph.com/issues/5038
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Get rid of rbd_img_request_get(), because it isn't used, and maybe
won't ever be needed.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Any changes to parent images are immaterial to any mapped clone.
So there is no need to have a watch event registered on header
objects except for the header object of an image that is mapped.
In fact, a watch request is a write operation, and we may only
have read access to a parent image.
We can't set up the watch request until we know the name of the
header object though. So pass a flag to rbd_dev_image_probe() to
indicate whether this probe is for a mapping or for a parent image.
Change the second parameter to rbd_dev_header_watch_sync() be
Boolean while we're at it.
This resolves:
http://tracker.ceph.com/issues/4941
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The rbd_dev->mapping field for a parent image is not meaningful.
Since rbd_image_probe() is used both for images being mapped and
their parents, it doesn't make sense to set that flag in that
function.
So move the setting of the mapping.read_only flag out of
rbd_dev_image_probe() and into rbd_add() instead.
This resolves:
http://tracker.ceph.com/issues/4940
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Currently, rbd_img_parent_read() assumes the incoming object request
contains bio data. But if a layered image is part of a multi-layer
stack of images it will result in read requests of page data to parent
images.
Fortunately, it's not hard to add support for page data.
This resolves:
http://tracker.ceph.com/issues/4939
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In rbd_img_obj_parent_read_full_callback() there is an assertion
intended to verify the size of the image request for a full parent
read was the size of the original request's target object. But
assertion was looking at the parent image order rather than the
original one, and these values can differ.
Fix that.
This resolves:
http://tracker.ceph.com/issues/4938
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This rearranges rbd_dev_v2_refresh() so it works more like
rbd_dev_v1_header_info(). While format 1 images need to read the
whole header object to get any information, format 2 can collect
almost all information selectively. So the one-time initialization
will remain in a separate function--based on rbd_dev_v2_probe().
Rename rbd_dev_v2_refresh() to be rbd_dev_v2_header_info(), and have
it call rbd_dev_v2_header_onetime() if it's being called for the
first time for the given rbd device.
Rename rbd_dev_v2_probe() to be rbd_dev_v2_header_onetime() and
remove the image size and snapshot context calls it held in
common with the refresh function.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Get rid of the trivial wrapper functions rbd_dev_v1_refresh() and
rbd_dev_v1_probe(), substituting rbd_dev_v1_header_read() calls
in their place.
Rename rbd_dev_v1_header_read() to be rbd_dev_v1_header_info(), to
be more generic (it will better reflect what happens with format 2
images).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An rbd_dev structure's fields are all zero-filled for an initial
probe, so there's no need to explicitly zero the parent_spec
and parent_overlap fields in rbd_dev_v1_probe(). Removing these
assignments makes rbd_dev_v1_probe() *almost* trivial.
Move the dout() message that announces discovery of an image into
rbd_dev_image_probe(), generalize to support images in either format
and only show it if an image is fully discovered.
This highlights that are some unnecessary cleanups in the error
path for rbd_dev_v1_probe(), so they can be removed.
Now rbd_dev_v1_probe() *is* a trivial wrapper function.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Now that rbd_header_from_disk() only fills in one-time fields once,
we can extend it slightly so it releases the other fields before
replacing their values. This way there's no need to pass a
temporary buffer and then copy all the results in. Just use the rbd
device header structure in rbd_header_from_disk() so its values get
updated directly.
Note that this means we need to take the header semaphore at the
point we update things. So pass the rbd_dev rather than the address
of its header as its first argument to rbd_header_from_disk(), and
have it return an error code.
As a result, rbd_dev_v1_header_read() does all the work,
rbd_read_header() becomes unnecessary, and rbd_dev_v1_refresh()
becomes a very simple wrapper.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
