The only thing ceph_osdc_alloc_request() really does with the
flags value it is passed is assign it to the newly-created
osd request structure. Do that in the caller instead.
Both callers subsequently call ceph_osdc_build_request(), so have
that function (instead of ceph_osdc_alloc_request()) issue a warning
if a request comes through with neither the read nor write flags set.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The osdc parameter to ceph_calc_raw_layout() is not used, so get rid
of it. Consequently, the corresponding parameter in calc_layout()
becomes unused, so get rid of that as well.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
A snapshot id must be provided to ceph_calc_raw_layout() even though
it is not needed at all for calculating the layout.
Where the snapshot id *is* needed is when building the request
message for an osd operation.
Drop the snapid parameter from ceph_calc_raw_layout() and pass
that value instead in ceph_osdc_build_request().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
ceph_calc_file_object_mapping() takes (among other things) a "file"
offset and length, and based on the layout, determines the object
number ("bno") backing the affected portion of the file's data and
the offset into that object where the desired range begins. It also
computes the size that should be used for the request--either the
amount requested or something less if that would exceed the end of
the object.
This patch changes the input length parameter in this function so it
is used only for input. That is, the argument will be passed by
value rather than by address, so the value provided won't get
updated by the function.
The value would only get updated if the length would surpass the
current object, and in that case the value it got updated to would
be exactly that returned in *oxlen.
Only one of the two callers is affected by this change. Update
ceph_calc_raw_layout() so it records any updated value.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The len argument to ceph_osdc_build_request() is set up to be
passed by address, but that function never updates its value
so there's no need to do this. Tighten up the interface by
passing the length directly.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Since every osd message is now prepared to include trailing data,
there's no need to check ahead of time whether any operations will
make use of the trail portion of the message.
We can drop the second argument to get_num_ops(), and as a result we
can also get rid of op_needs_trail() which is no longer used.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
An osd request structure contains an optional trail portion, which
if present will contain data to be passed in the payload portion of
the message containing the request. The trail field is a
ceph_pagelist pointer, and if null it indicates there is no trail.
A ceph_pagelist structure contains a length field, and it can
legitimately hold value 0. Make use of this to change the
interpretation of the "trail" of an osd request so that every osd
request has trailing data, it just might have length 0.
This means we change the r_trail field in a ceph_osd_request
structure from a pointer to a structure that is always initialized.
Note that in ceph_osdc_start_request(), the trail pointer (or now
address of that structure) is assigned to a ceph message's trail
field. Here's why that's still OK (looking at net/ceph/messenger.c):
- What would have resulted in a null pointer previously will now
refer to a 0-length page list. That message trail pointer
is used in two functions, write_partial_msg_pages() and
out_msg_pos_next().
- In write_partial_msg_pages(), a null page list pointer is
handled the same as a message with 0-length trail, and both
result in a "in_trail" variable set to false. The trail
pointer is only used if in_trail is true.
- The only other place the message trail pointer is used is
out_msg_pos_next(). That function is only called by
write_partial_msg_pages() and only touches the trail pointer
if the in_trail value it is passed is true.
Therefore a null ceph_msg->trail pointer is equivalent to a non-null
pointer referring to a 0-length page list structure.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
For some reason, the snapid field of the osd request header is
explicitly set to CEPH_NOSNAP in rbd_do_request(). Just a few lines
later--with no code that would access this field in between--a call
is made to ceph_calc_raw_layout() passing the snapid provided to
rbd_do_request(), which encodes the snapid value it is provided into
that field instead.
In other words, there is no need to fill in CEPH_NOSNAP, and doing
so suggests it might be necessary. Don't do that any more.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The snapc and snapid parameters to rbd_req_sync_op() always take
the values NULL and CEPH_NOSNAP, respectively. So just get rid
of them and use those values where needed.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
All callers of rbd_req_sync_exec() pass CEPH_OSD_FLAG_READ as their
flags argument. Delete that parameter and use CEPH_OSD_FLAG_READ
within the function. If we find a need to support write operations
we can add it back again.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There is only one caller of rbd_req_sync_read(), and it passes
CEPH_NOSNAP as the snapshot id argument. Delete that parameter
and just use CEPH_NOSNAP within the function.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The last two parameters to ceph_osd_build_request() describe the
object id, but the values passed always come from the osd request
structure whose address is also provided. Get rid of those last
two parameters.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Pull a block of code that initializes the layout structure in an osd
request into its own function so it can be reused.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Right now we get the snapshot context for an rbd image (under
protection of the header semaphore) for every request processed.
There's no need to get the snap context if we're doing a read,
so avoid doing so in that case.
Note that we no longer need to hold the header semaphore to
check the rbd_dev's existence flag.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The rbd_device->exists field can be updated asynchronously, changing
from set to clear if a mapped snapshot disappears from the base
image's snapshot context.
Currently, value of the "exists" flag is only read and modified
under protection of the header semaphore, but that will change with
the next patch. Making it atomic ensures this won't be a problem
because the a the non-existence of device will be immediately known.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Now that a big hunk in the middle of rbd_rq_fn() has been moved
into its own routine we can simplify it a little more.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Only one of the three callers of rbd_do_request() provide a
collection structure to aggregate status.
If an error occurs in rbd_do_request(), have the caller
take care of calling rbd_coll_end_req() if necessary in
that one spot.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
In rbd_rq_fn(), requests are fetched from the block layer and each
request is processed, looping through the request's list of bio's
until they've all been consumed.
Separate the handling for a single request into its own function to
make it a bit easier to see what's going on.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
The result field in a ceph osd reply header is a signed 32-bit type,
but rbd code often casually uses int to represent it.
The following changes the types of variables that handle this result
value to be "s32" instead of "int" to be completely explicit about
it. Only at the point we pass that result to __blk_end_request()
does the type get converted to the plain old int defined for that
interface.
There is almost certainly no binary impact of this change, but I
prefer to show the exact size and signedness of the value since we
know it.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
There are spots where a ceph_osds_request pointer variable is given
the name "req". Since we're dealing with (at least) three types of
requests (block layer, rbd, and osd), I find this slightly
distracting.
Change such instances to use "osd_req" consistently to make the
abstraction represented a little more obvious.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
There are two names used for items of rbd_request structure type:
"req" and "req_data". The former name is also used to represent
items of pointers to struct ceph_osd_request.
Change all variables that have these names so they are instead
called "rbd_req" consistently.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Josh suggested adding warnings to this function to help users
diagnose problems.
Other than memory allocatino errors, there are two places where
errors can be returned. Both represent problems that should
have been caught earlier, and as such might well have been
handled with BUG_ON() calls. But if either ever did manage to
happen, it will be reported.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Add a warning in bio_chain_clone_range() to help a user determine
what exactly might have led to a failure. There is only one; please
say something if you disagree with the following reasoning.
There are three places this can return abnormally:
- Initially, if there is nothing to clone. It turns out that
right now this cannot happen anyway. The test is in place
because the code below it doesn't work if those conditions
don't hold. As such they could be assertions but since I can
return a null to indicate an error I just do that instead.
I have not added a warning here because it won't happen.
- While processing bio's, if none remain but there are supposed
to be more bytes to clone. Here I have added a warning.
- If bio_clone_range() returns a null pointer. That function
will have already produced a warning (at least the first
time, via WARN_ON_ONCE()) to distinguish the cause of the
error. The only exception is memory exhaustion, and I'd
rather not pepper the code with warnings in all those spots.
So no warning is added in that place.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Tell the user (via dmesg) what was wrong with the arguments provided
via /sys/bus/rbd/add.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
Define a new function rbd_warn() that produces a boilerplate warning
message, identifying in the resulting message the affected rbd
device in the best way available. Use it in a few places that now
use pr_warning().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Alex Elder
Alex Elder