This implements the main copyup functionality for layered writes.
Here we add a copyup_pages field to the object request, which is
used only for copyup requests to keep track of the page array
containing data read from the parent image.
A copyup request is currently the only request rbd has that requires
two osd operations. Because of this we handle copyup specially.
All image object requests get an osd request allocated when they are
created. For a write request, if a copyup is required, the osd
request originally allocated is released, and a new one (with room
for two osd ops) is allocated to replace it. A new function
rbd_osd_req_create_copyup() allocates an osd request suitable for
a copyup request.
The first op is then filled with a copyup object class method call,
supplying the array of pages containing data read from the parent.
The second op is filled in with the original write request.
The original request otherwise remains intact, and it describes the
original write request (found in the second osd op). The presence
of the copyup op is sort of implicit; a non-null copyup_pages field
could be used to distinguish between a "normal" write request and a
request containing both a copyup call and a write.
This resolves:
http://tracker.ceph.com/issues/3419
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
As a step toward implementing layered writes, implement reading the
data for a target object from the parent image for a write request
whose target object is known to not exist. Add a copyup_pages field
to an image request to track the page array used (only) for such a
request.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
If rbd disk is open and rbd resize is done, new size is not
visible by filesystem. Like is done in virtio-blk and dm driver,
revalidate_disk() permits to update the bd_inode size.
Signed-off-by: Laurent Barbe <laurent@ksperis.com>
Reviewed-by: Alex Elder <elder@inktank.com>
This patch adds the ability to build an image request whose data
will be written from or read into memory described by a page array.
(Previously only bio lists were supported.)
Originally this was going to define a new function for this purpose
but it was largely identical to the rbd_img_request_fill_bio(). So
instead, rbd_img_request_fill_bio() has been generalized to handle
both types of image request.
For the moment we still only fill image requests with bio data.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a new function zero_pages() that zeroes a range of memory
defined by a page array, along the lines of zero_bio_chain(). It
saves and the irq flags like bvec_kmap_irq() does, though I'm not
sure at this point that it's necessary.
Update rbd_img_obj_request_read_callback() to use the new function
if the object request contains page rather than bio data.
For the moment, only bio data is used for osd READ ops.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Object requests that are part of an image request are subject to
some additional handling. Define rbd_img_obj_request_submit() to
encapsulate that, and use it when initially submitting an image
object request, and when re-submitting it during callback of
an object existence check.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Separate rbd_osd_req_format() into two functions, one for read
requests and the other for write requests.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This is a step toward fully implementing layered writes.
Add checks before request submission for the object(s) associated
with an image request. For write requests, if we don't know that
the target object exists, issue a STAT request to find out. When
that request completes, mark the known and exists flags for the
original object request accordingly and re-submit the object
request. (Note that this still does the existence check only; the
copyup operation is not yet done.)
A new object request is created to perform the existence check. A
pointer to the original request is added to that object request to
allow the stat request to re-issue the original request after
updating its flags. If there is a failure with the stat request
the error code is stored with the original request, which is then
completed.
This resolves:
http://tracker.ceph.com/issues/3418
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This creates two new flags for object requests to indicate what is
known about the existence of the object to which a request is to be
sent. The KNOWN flag will be true if the the EXISTS flag is
meaningful. That is:
KNOWN EXISTS
----- ------
0 0 don't know whether the object exists
0 1 (not used/invalid)
1 0 object is known to not exist
1 0 object is known to exist
This will be used in determining how to handle write requests for
data objects for layered rbd images.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In a few spots, whether the an object request's img_request pointer
is null is used to determine whether an object request is being done
as part of an image data request.
Stop doing that, and instead always use the object request IMG_DATA
flag for that purpose. Swap the order of the definition of the
IMG_DATA and DONE flag helpers, because obj_request_done_set() now
refers to obj_request_img_data_set() to get its rbd_dev value.
This will become important because the img_request pointer is
about to become part of a union.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An extra reference is taken when an object request is added as one
of the requests making up an image object. A reference is dropped
again when the image's object requests get submitted.
The original reference for the object request will remain throughout
this period, so we don't need to add and then take away an extra
one.
This can be interpreted as the image request inheriting the original
object request's reference.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In the incremental move toward supporting distinct data items in an
osd request some of the functions had "write_request" parameters to
indicate, basically, whether the data belonged to in_data or the
out_data. Now that we maintain the data fields in the op structure
there is no need to indicate the direction, so get rid of the
"write_request" parameters.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Implement layered read requests for format 2 rbd images.
If an rbd image is a clone of a snapshot, the snapshot will be the
clone's "parent" image. When an object read request on a clone
comes back with ENOENT it indicates that the clone is not yet
populated with that portion of the image's data, and the parent
image should be consulted to satisfy the read.
When this occurs, a new image request is created, directed to the
parent image. The offset and length of the image are the same as
the image-relative offset and length of the object request that
produced ENOENT. Data from the parent image therefore satisfies the
object read request for the original image request.
While this code works, it will not be active until we enable the
layering feature (by adding RBD_FEATURE_LAYERING to the value of
RBD_FEATURES_SUPPORTED).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Call the probe function for the parent device if one is present.
Since we don't formally support the layering feature we won't
be using this functionality just yet.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Add a flag to distinguish between object requests being done on
standalone objects and requests being sent for objects representing
rbd image data (i.e., object requests that are the result of image
request).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
We're going to need some more Boolean values for object requests,
so create a flags bit field and use it to record whether the request
is done.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Encapsulate the code that completes processing of an object request
that's part of an image request.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a flag indicating whether an image request is for a layered
image (one with a parent image to which requests will be redirected
if the target object of a request does not exist). The code that
checks this flag will be added shortly.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define a flag indicating whether an image request originated from
the Linux block layer (from blk_fetch_request()) or whether it was
initiated in order to satisfy an object request for a child image
of a layered rbd device. For image requests initiated by objects of
child images we'll save a pointer to the object request rather than
the Linux block request.
For now, only block requests are used.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There are several Boolean values we'll be maintaining for image
requests. Switch from the single write_request field to a
general-purpose flags field, and use one if its bits to represent
the direction of I/O for the image request. Define helper functions
for setting and testing that flag.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
For an image object request we will need to know what offset within
the rbd image the request covers. Record that when the object
request gets created.
Update the I/O error warnings so they use this so what's reported
is more informative.
Rename a local variable to fit the convention used everywhere else.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Compute the total number of bytes transferred for an image
request--the sum across each of the request's object requests.
To avoid contention do it only when all object requests are
complete, in rbd_img_request_complete().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
If any image object request produces a non-zero result, preserve
that as the result of the overall image request. If multiple
objects have non-zero results, save only the first one.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There is a new rbd feature bit defined for "fancy striping." Add
it to the ones defined in the kernel client.
Change RBD_FEATURES_ALL so it represents the set of all feature
bits (rather than just the ones we support). Define a new symbol
RBD_FEATURES_SUPPORTED to indicate the supported ones.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Right now the data for a method call is specified via a pointer and
length, and it's copied--along with the class and method name--into
a pagelist data item to be sent to the osd. Instead, encode the
data in a data item separate from the class and method names.
This will allow large amounts of data to be supplied to methods
without copying. Only rbd uses the class functionality right now,
and when it really needs this it will probably need to use a page
array rather than a page list. But this simple implementation
demonstrates the functionality on the osd client, and that's enough
for now.
This resolves:
http://tracker.ceph.com/issues/4104
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This ends up being a rather large patch but what it's doing is
somewhat straightforward.
Basically, this is replacing two calls with one. The first of the
two calls is initializing a struct ceph_osd_data with data (either a
page array, a page list, or a bio list); the second is setting an
osd request op so it associates that data with one of the op's
parameters. In place of those two will be a single function that
initializes the op directly.
That means we sort of fan out a set of the needed functions:
- extent ops with pages data
- extent ops with pagelist data
- extent ops with bio list data
and
- class ops with page data for receiving a response
We also have define another one, but it's only used internally:
- class ops with pagelist data for request parameters
Note that we *still* haven't gotten rid of the osd request's
r_data_in and r_data_out fields. All the osd ops refer to them for
their data. For now, these data fields are pointers assigned to the
appropriate r_data_* field when these new functions are called.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This patch just trivially moves around some code for consistency.
In preparation for initializing osd request data fields in
ceph_osdc_build_request(), I wanted to verify that rbd did in fact
call that immediately before it called ceph_osdc_start_request().
It was true (although image requests are built in a group and then
started as a group). But I made the changes here just to make
it more obvious, by making all of the calls follow a common
sequence:
osd_req_op_<optype>_init();
ceph_osd_data_<type>_init()
osd_req_op_<optype>_<datafield>()
rbd_osd_req_format()
...
ret = rbd_obj_request_submit()
I moved the initialization of the callback for image object requests
into rbd_img_request_fill_bio(), again, for consistency. To avoid
a forward reference, I moved the definition of rbd_img_obj_callback()
up in the file.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The osd data for a request is currently initialized inside
rbd_osd_req_create(), but that assumes an object request's data
belongs in the osd request's data in or data out field.
There are only three places where requests with data are set up, and
it turns out it's easier to call just the osd data init routines
directly there rather than handling it in rbd_osd_req_create().
(The real motivation here is moving toward getting rid of the
osd request in and out data fields.)
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Currently an object request has its osd request's data field set in
rbd_osd_req_format_op(). That assumes a single osd op per object
request, and that won't be the case for long.
Move the code that sets this out and into the caller.
Rename rbd_osd_req_format_op() to be just rbd_osd_req_format(),
removing the notion that it's doing anything op-specific.
This and the next patch resolve:
http://tracker.ceph.com/issues/4658
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request now holds all of its source op structures, and every
place that initializes one of these is in fact initializing one
of the entries in the the osd request's array.
So rather than supplying the address of the op to initialize, have
caller specify the osd request and an indication of which op it
would like to initialize. This better hides the details the
op structure (and faciltates moving the data pointers they use).
Since osd_req_op_init() is a common routine, and it's not used
outside the osd client code, give it static scope. Also make
it return the address of the specified op (so all the other
init routines don't have to repeat that code).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An extent type osd operation currently implies that there will
be corresponding data supplied in the data portion of the request
(for write) or response (for read) message. Similarly, an osd class
method operation implies a data item will be supplied to receive
the response data from the operation.
Add a ceph_osd_data pointer to each of those structures, and assign
it to point to eithre the incoming or the outgoing data structure in
the osd message. The data is not always available when an op is
initially set up, so add two new functions to allow setting them
after the op has been initialized.
Begin to make use of the data item pointer available in the osd
operation rather than the request data in or out structure in
places where it's convenient. Add some assertions to verify
pointers are always set the way they're expected to be.
This is a sort of stepping stone toward really moving the data
into the osd request ops, to allow for some validation before
making that jump.
This is the first in a series of patches that resolve:
http://tracker.ceph.com/issues/4657
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request keeps a pointer to the osd operations (ops) array
that it builds in its request message.
In order to allow each op in the array to have its own distinct
data, we will need to keep track of each op's data, and that
information does not go over the wire.
As long as we're tracking the data we might as well just track the
entire (source) op definition for each of the ops. And if we're
doing that, we'll have no more need to keep a pointer to the
wire-encoded version.
This patch makes the array of source ops be kept with the osd
request structure, and uses that instead of the version encoded in
the message in places where that was previously used. The array
will be embedded in the request structure, and the maximum number of
ops we ever actually use is currently 2. So reduce CEPH_OSD_MAX_OP
to 2 to reduce the size of the structure.
The result of doing this sort of ripples back up, and as a result
various function parameters and local variables become unnecessary.
Make r_num_ops be unsigned, and move the definition of struct
ceph_osd_req_op earlier to ensure it's defined where needed.
It does not yet add per-op data, that's coming soon.
This resolves:
http://tracker.ceph.com/issues/4656
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define rbd_osd_req_format_op(), which encapsulates formatting
an osd op into an object request's osd request message. Only
one op is supported right now.
Stop calling ceph_osdc_build_request() in rbd_osd_req_create().
Instead, call rbd_osd_req_format_op() in each of the callers of
rbd_osd_req_create().
This is to prepare for the next patch, in which the source ops for
an osd request will be held in the osd request itself. Because of
that, we won't have the source op to work with until after the
request is created, so we can't format the op until then.
This an the next patch resolve:
http://tracker.ceph.com/issues/4656
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Define and use functions that encapsulate the initializion of a
ceph_osd_data structure.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When rbd creates an object request containing an object method call
operation it is passing 0 for the size. I originally thought this
was because the length was not needed for method calls, but I think
it really should be supplied, to describe how much space is
available to receive response data. So provide the supplied length.
This resolves:
http://tracker.ceph.com/issues/4659
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
When assigning a bio pointer to an osd request, we don't have an
efficient way of knowing the total length bytes in the bio list.
That information is available at the point it's set up by the rbd
code, so record it with the osd data when it's set.
This and the next patch are related to maintaining the length of a
message's data independent of the message header, as described here:
http://tracker.ceph.com/issues/4589
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The rbd code has a function that allocates and populates a
ceph_osd_req_op structure (the in-core version of an osd request
operation). When reviewed, Josh suggested two things: that the
big varargs function might be better split into type-specific
functions; and that this functionality really belongs in the osd
client rather than rbd.
This patch implements both of Josh's suggestions. It breaks
up the rbd function into separate functions and defines them
in the osd client module as exported interfaces. Unlike the
rbd version, however, the functions don't allocate an osd_req_op
structure; they are provided the address of one and that is
initialized instead.
The rbd function has been eliminated and calls to it have been
replaced by calls to the new routines. The rbd code now now use a
stack (struct) variable to hold the op rather than allocating and
freeing it each time.
For now only the capabilities used by rbd are implemented.
Implementing all the other osd op types, and making the rest of the
code use it will be done separately, in the next few patches.
Note that only the extent, cls, and watch portions of the
ceph_osd_req_op structure are currently used. Delete the others
(xattr, pgls, and snap) from its definition so nobody thinks it's
actually implemented or needed. We can add it back again later
if needed, when we know it's been tested.
This (and a few follow-on patches) resolves:
http://tracker.ceph.com/issues/3861
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Move some definitions for max integer values out of the rbd code and
into the more central "decode.h" header file. These really belong
in a Linux (or libc) header somewhere, but I haven't gotten around
to proposing that yet.
This is in preparation for moving some code out of rbd.c and into
the osd client.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The length of outgoing data in an osd request is dependent on the
osd ops that are embedded in that request. Each op is encoded into
a request message using osd_req_encode_op(), so that should be used
to determine the amount of outgoing data implied by the op as it
is encoded.
Have osd_req_encode_op() return the number of bytes of outgoing data
implied by the op being encoded, and accumulate and use that in
ceph_osdc_build_request().
As a result, ceph_osdc_build_request() no longer requires its "len"
parameter, so get rid of it.
Using the sum of the op lengths rather than the length provided is
a valid change because:
- The only callers of osd ceph_osdc_build_request() are
rbd and the osd client (in ceph_osdc_new_request() on
behalf of the file system).
- When rbd calls it, the length provided is only non-zero for
write requests, and in that case the single op has the
same length value as what was passed here.
- When called from ceph_osdc_new_request(), (it's not all that
easy to see, but) the length passed is also always the same
as the extent length encoded in its (single) write op if
present.
This resolves:
http://tracker.ceph.com/issues/4406
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Record the byte count for an osd request rather than the page count.
The number of pages can always be derived from the byte count (and
alignment/offset) but the reverse is not true.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request defines information about where data to be read
should be placed as well as where data to write comes from.
Currently these are represented by common fields.
Keep information about data for writing separate from data to be
read by splitting these into data_in and data_out fields.
This is the key patch in this whole series, in that it actually
identifies which osd requests generate outgoing data and which
generate incoming data. It's less obvious (currently) that an osd
CALL op generates both outgoing and incoming data; that's the focus
of some upcoming work.
This resolves:
http://tracker.ceph.com/issues/4127
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request uses either pages or a bio list for its data. Use a
union to record information about the two, and add a data type
tag to select between them.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Pull the fields in an osd request structure that define the data for
the request out into a separate structure.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
It's possible that the reference to the object request dropped
inside the loop in rbd_img_request_submit() will be the last
one, in which case the content of the object pointer can't be
trusted.
Use a safe form of the object request list traversal to avoid
problems.
This resolves:
http://tracker.ceph.com/issues/4705
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
A result of ENOENT from a read request for an object that's part of
an rbd image indicates that there is a hole in that portion of the
image. Similarly, a short read for such an object indicates that
the remainder of the read should be interpreted a full read with
zeros filling out the end of the request.
This behavior is not correct for objects that are not backing rbd
image data. Currently rbd_img_obj_request_callback() assumes it
should be done for all objects.
Change rbd_img_obj_request_callback() so it only does this zeroing
for image objects. Encapsulate that special handling in its own
function. Add an assertion that the image object request is a bio
request, since we assume that (and we currently don't support any
other types).
This resolves a problem identified here:
http://tracker.ceph.com/issues/4559
The regression was introduced by bf0d5f503d.
Reported-by: Dan van der Ster <dan@vanderster.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-off-by: Sage Weil <sage@inktank.com>
Use the new version of the encoding for osd requests and replies. In the
process, update the way we are tracking request ops and reply lengths and
results in the struct ceph_osd_request. Update the rbd and fs/ceph users
appropriately.
The main changes are:
- we keep pointers into the request memory for fields we need to update
each time the request is sent out over the wire
- we keep information about the result in an array in the request struct
where the users can easily get at it.
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
The only thing type-specific osd completion functions do with their
osd op parameter is (in some cases) extract the number of bytes
transferred from it. In the other cases, the xferred bytes field
is not used, and total message data transfer byte count (which may
well be zero) is used.
Just set the object request transfer count in the main osd request
callback function and provide that to the other routines. There is
then no longer any need to pass the op pointer to the type-specific
completion routines, so drop those parameters.
Stop doing anything with the total message data length.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
This function is slightly out of place, probably the result
of an errant automatic merge or something.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Fengguang Wu reminded me that there were outstanding sparse reports
in the ceph and rbd code. This patch fixes these problems in rbd
that lead to those reports:
- Convert functions that are never referenced externally to have
static scope.
- Add a lockdep annotation to rbd_request_fn(), because it
releases a lock before acquiring it again.
This partially resolves:
http://tracker.ceph.com/issues/4184
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Add dout() calls to facilitate tracing of image and object requests.
Change a few existing calls so they use __func__ rather than the
hard-coded function name. Have calls always add ":" after the name
of the function, and prefix pointer values with a consistent tag
indicating what it represents. (Note that there remain some older
dout() calls that are left untouched by this patch.)
Issue a warning if rbd_osd_write_callback() ever gets a short write.
This resolves:
http://tracker.ceph.com/issues/4235
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Alex Elder
Laurent Barbe
Sage Weil