If the layout is "fancy", we need to be able to rearrange the provided
bio_vecs in stripe unit chunks to make it possible for the messenger to
read/write directly from/to the provided data buffer, without employing
a temporary data buffer for assembling the result.
Higher level bio_vec arrays are generally immutable, so this requires
copying into a private array. Only the bio_vecs themselves are shuffled
around, not the actual data. OWN_BVECS doesn't own any pages.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
rbd_parent_request_create() takes a ref on obj_req for child_img_req.
There is no point in doing that because child_img_req is created on
behalf of obj_req -- obj_req is the initiator and can't be completed
before child_img_req.
Open-code the rest of rbd_parent_request_create() and remove it along
with rbd_parent_request_destroy().
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
A whole-object layered discard is implemented as a truncate rather
than a delete: a dummy object is needed to prevent the CoW machinery
from kicking in. However, a truncate on a non-existent object is
a no-op. If the object doesn't exist in HEAD, a discard request is
effectively ignored, which violates our "discard zeroes data" promise
and breaks REQ_OP_WRITE_ZEROES implementation.
A non-exclusive create on an existing object is also a no-op, so the
fix is to do a compound create+truncate instead.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
In preparation for rbd "fancy" striping, replace obj_req->img_offset
with obj_req->img_extents. A single starting offset isn't sufficient
because we want only one OSD request per object and will merge adjacent
object extents in ceph_file_to_extents(). The final object extent may
map into multiple different byte ranges in the image.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
obj_req->object_no -> obj_req->ex.oe_objno
obj_req->offset -> obj_req->ex.oe_off
obj_req->length -> obj_req->ex.oe_len
... and use ex for linking object requests to image requests.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
All object requests are associated with an image request now -- avoid
duplicating the same info in each object request.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Do away with partial request completions and all the associated
complexity. Individual object requests no longer need to be completed
in order -- when the last one becomes ready, we complete the entire
higher level request all at once.
This also wraps up the conversion to a state machine model and
eliminates the recursion described in commit 6d69bb536b ("rbd:
prevent kernel stack blow up on rbd map").
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
It should be void now. Also, object requests are unlinked only in
image request destructor, which can't run before rbd_img_request_put(),
so no need for _safe.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
No need to pass rbd_dev and op_type to rbd_osd_req_create(): there are
no standalone (!IMG_DATA) object requests anymore and osd_req->r_flags
can be set in rbd_osd_req_format_{read,write}().
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
The notable changes are:
- instead of explicitly stat'ing the object to see if it exists before
issuing the write, send the write optimistically along with the stat
in a single OSD request
- zero copyup optimization
- all object requests are associated with an image request and have
a valid ->img_request pointer; there are no standalone (!IMG_DATA)
object requests anymore
- code is structured as a state machine (vs a bunch of callbacks with
implicit state)
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
rbd needs this for null copyups -- if copyup data is all zeroes, we
want to save some I/O and network bandwidth. See rbd_obj_issue_copyup()
in the next commit.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
In preparation for rbd "fancy" striping which requires bio_vec arrays,
wire up BVECS data type and kill off PAGES data type. There is nothing
wrong with using page vectors for copyup requests -- it's just less
iterator boilerplate code to write for the new striping framework.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
In preparation for rbd "fancy" striping, introduce ceph_bvec_iter for
working with bio_vec array data buffers. The wrappers are trivial, but
make it look similar to ceph_bio_iter.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
The initiating object request is the proper owner -- save a bit of
space.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
obj_req->pages is for provided data buffers. stat requests are
internal and should be NODATA.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Ilya Dryomov