rbd: introduce OWN_BVECS data type
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>
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@ -215,6 +215,7 @@ enum obj_request_type {
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OBJ_REQUEST_NODATA = 1,
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OBJ_REQUEST_BIO, /* pointer into provided bio (list) */
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OBJ_REQUEST_BVECS, /* pointer into provided bio_vec array */
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OBJ_REQUEST_OWN_BVECS, /* private bio_vec array, doesn't own pages */
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};
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enum obj_operation_type {
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@ -261,6 +262,7 @@ struct rbd_obj_request {
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struct {
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struct ceph_bvec_iter bvec_pos;
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u32 bvec_count;
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u32 bvec_idx;
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};
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};
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struct bio_vec *copyup_bvecs;
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@ -1238,7 +1240,7 @@ static void zero_bvecs(struct ceph_bvec_iter *bvec_pos, u32 off, u32 bytes)
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/*
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* Zero a range in @obj_req data buffer defined by a bio (list) or
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* bio_vec array.
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* (private) bio_vec array.
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*
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* @off is relative to the start of the data buffer.
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*/
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@ -1250,6 +1252,7 @@ static void rbd_obj_zero_range(struct rbd_obj_request *obj_req, u32 off,
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zero_bios(&obj_req->bio_pos, off, bytes);
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break;
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case OBJ_REQUEST_BVECS:
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case OBJ_REQUEST_OWN_BVECS:
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zero_bvecs(&obj_req->bvec_pos, off, bytes);
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break;
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default:
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@ -1485,6 +1488,9 @@ static void rbd_obj_request_destroy(struct kref *kref)
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case OBJ_REQUEST_BIO:
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case OBJ_REQUEST_BVECS:
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break; /* Nothing to do */
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case OBJ_REQUEST_OWN_BVECS:
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kfree(obj_request->bvec_pos.bvecs);
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break;
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default:
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rbd_assert(0);
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}
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@ -1679,8 +1685,10 @@ static void rbd_osd_req_setup_data(struct rbd_obj_request *obj_req, u32 which)
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obj_req->ex.oe_len);
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break;
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case OBJ_REQUEST_BVECS:
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case OBJ_REQUEST_OWN_BVECS:
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rbd_assert(obj_req->bvec_pos.iter.bi_size ==
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obj_req->ex.oe_len);
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rbd_assert(obj_req->bvec_idx == obj_req->bvec_count);
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osd_req_op_extent_osd_data_bvec_pos(obj_req->osd_req, which,
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&obj_req->bvec_pos);
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break;
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@ -1893,6 +1901,8 @@ struct rbd_img_fill_ctx {
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union rbd_img_fill_iter *pos;
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union rbd_img_fill_iter iter;
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ceph_object_extent_fn_t set_pos_fn;
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ceph_object_extent_fn_t count_fn;
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ceph_object_extent_fn_t copy_fn;
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};
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static struct ceph_object_extent *alloc_object_extent(void *arg)
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@ -1909,15 +1919,18 @@ static struct ceph_object_extent *alloc_object_extent(void *arg)
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}
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/*
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* Map a list of image extents to a list of object extents, create the
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* corresponding object requests (normally each to a different object,
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* but not always) and add them to @img_req. For each object request,
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* set up its data descriptor to point to the corresponding chunk of
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* @fctx->pos data buffer.
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*
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* @fctx->pos data buffer is assumed to be large enough.
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* While su != os && sc == 1 is technically not fancy (it's the same
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* layout as su == os && sc == 1), we can't use the nocopy path for it
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* because ->set_pos_fn() should be called only once per object.
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* ceph_file_to_extents() invokes action_fn once per stripe unit, so
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* treat su != os && sc == 1 as fancy.
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*/
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static int rbd_img_fill_request(struct rbd_img_request *img_req,
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static bool rbd_layout_is_fancy(struct ceph_file_layout *l)
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{
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return l->stripe_unit != l->object_size;
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}
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static int rbd_img_fill_request_nocopy(struct rbd_img_request *img_req,
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struct ceph_file_extent *img_extents,
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u32 num_img_extents,
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struct rbd_img_fill_ctx *fctx)
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@ -1946,6 +1959,81 @@ static int rbd_img_fill_request(struct rbd_img_request *img_req,
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return __rbd_img_fill_request(img_req);
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}
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/*
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* Map a list of image extents to a list of object extents, create the
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* corresponding object requests (normally each to a different object,
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* but not always) and add them to @img_req. For each object request,
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* set up its data descriptor to point to the corresponding chunk(s) of
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* @fctx->pos data buffer.
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*
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* Because ceph_file_to_extents() will merge adjacent object extents
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* together, each object request's data descriptor may point to multiple
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* different chunks of @fctx->pos data buffer.
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*
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* @fctx->pos data buffer is assumed to be large enough.
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*/
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static int rbd_img_fill_request(struct rbd_img_request *img_req,
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struct ceph_file_extent *img_extents,
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u32 num_img_extents,
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struct rbd_img_fill_ctx *fctx)
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{
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struct rbd_device *rbd_dev = img_req->rbd_dev;
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struct rbd_obj_request *obj_req;
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u32 i;
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int ret;
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if (fctx->pos_type == OBJ_REQUEST_NODATA ||
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!rbd_layout_is_fancy(&rbd_dev->layout))
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return rbd_img_fill_request_nocopy(img_req, img_extents,
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num_img_extents, fctx);
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img_req->data_type = OBJ_REQUEST_OWN_BVECS;
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/*
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* Create object requests and determine ->bvec_count for each object
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* request. Note that ->bvec_count sum over all object requests may
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* be greater than the number of bio_vecs in the provided bio (list)
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* or bio_vec array because when mapped, those bio_vecs can straddle
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* stripe unit boundaries.
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*/
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fctx->iter = *fctx->pos;
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for (i = 0; i < num_img_extents; i++) {
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ret = ceph_file_to_extents(&rbd_dev->layout,
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img_extents[i].fe_off,
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img_extents[i].fe_len,
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&img_req->object_extents,
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alloc_object_extent, img_req,
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fctx->count_fn, &fctx->iter);
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if (ret)
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return ret;
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}
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for_each_obj_request(img_req, obj_req) {
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obj_req->bvec_pos.bvecs = kmalloc_array(obj_req->bvec_count,
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sizeof(*obj_req->bvec_pos.bvecs),
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GFP_NOIO);
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if (!obj_req->bvec_pos.bvecs)
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return -ENOMEM;
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}
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/*
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* Fill in each object request's private bio_vec array, splitting and
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* rearranging the provided bio_vecs in stripe unit chunks as needed.
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*/
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fctx->iter = *fctx->pos;
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for (i = 0; i < num_img_extents; i++) {
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ret = ceph_iterate_extents(&rbd_dev->layout,
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img_extents[i].fe_off,
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img_extents[i].fe_len,
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&img_req->object_extents,
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fctx->copy_fn, &fctx->iter);
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if (ret)
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return ret;
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}
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return __rbd_img_fill_request(img_req);
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}
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static int rbd_img_fill_nodata(struct rbd_img_request *img_req,
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u64 off, u64 len)
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{
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@ -1970,6 +2058,32 @@ static void set_bio_pos(struct ceph_object_extent *ex, u32 bytes, void *arg)
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ceph_bio_iter_advance(it, bytes);
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}
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static void count_bio_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
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{
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struct rbd_obj_request *obj_req =
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container_of(ex, struct rbd_obj_request, ex);
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struct ceph_bio_iter *it = arg;
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dout("%s objno %llu bytes %u\n", __func__, ex->oe_objno, bytes);
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ceph_bio_iter_advance_step(it, bytes, ({
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obj_req->bvec_count++;
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}));
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}
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static void copy_bio_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
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{
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struct rbd_obj_request *obj_req =
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container_of(ex, struct rbd_obj_request, ex);
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struct ceph_bio_iter *it = arg;
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dout("%s objno %llu bytes %u\n", __func__, ex->oe_objno, bytes);
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ceph_bio_iter_advance_step(it, bytes, ({
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obj_req->bvec_pos.bvecs[obj_req->bvec_idx++] = bv;
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obj_req->bvec_pos.iter.bi_size += bv.bv_len;
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}));
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}
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static int __rbd_img_fill_from_bio(struct rbd_img_request *img_req,
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struct ceph_file_extent *img_extents,
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u32 num_img_extents,
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@ -1979,6 +2093,8 @@ static int __rbd_img_fill_from_bio(struct rbd_img_request *img_req,
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.pos_type = OBJ_REQUEST_BIO,
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.pos = (union rbd_img_fill_iter *)bio_pos,
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.set_pos_fn = set_bio_pos,
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.count_fn = count_bio_bvecs,
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.copy_fn = copy_bio_bvecs,
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};
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return rbd_img_fill_request(img_req, img_extents, num_img_extents,
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@ -2005,6 +2121,29 @@ static void set_bvec_pos(struct ceph_object_extent *ex, u32 bytes, void *arg)
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ceph_bvec_iter_advance(it, bytes);
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}
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static void count_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
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{
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struct rbd_obj_request *obj_req =
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container_of(ex, struct rbd_obj_request, ex);
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struct ceph_bvec_iter *it = arg;
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ceph_bvec_iter_advance_step(it, bytes, ({
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obj_req->bvec_count++;
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}));
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}
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static void copy_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
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{
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struct rbd_obj_request *obj_req =
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container_of(ex, struct rbd_obj_request, ex);
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struct ceph_bvec_iter *it = arg;
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ceph_bvec_iter_advance_step(it, bytes, ({
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obj_req->bvec_pos.bvecs[obj_req->bvec_idx++] = bv;
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obj_req->bvec_pos.iter.bi_size += bv.bv_len;
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}));
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}
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static int __rbd_img_fill_from_bvecs(struct rbd_img_request *img_req,
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struct ceph_file_extent *img_extents,
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u32 num_img_extents,
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@ -2014,6 +2153,8 @@ static int __rbd_img_fill_from_bvecs(struct rbd_img_request *img_req,
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.pos_type = OBJ_REQUEST_BVECS,
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.pos = (union rbd_img_fill_iter *)bvec_pos,
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.set_pos_fn = set_bvec_pos,
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.count_fn = count_bvecs,
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.copy_fn = copy_bvecs,
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};
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return rbd_img_fill_request(img_req, img_extents, num_img_extents,
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@ -2071,6 +2212,7 @@ static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req)
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&obj_req->bio_pos);
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break;
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case OBJ_REQUEST_BVECS:
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case OBJ_REQUEST_OWN_BVECS:
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ret = __rbd_img_fill_from_bvecs(child_img_req,
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obj_req->img_extents,
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obj_req->num_img_extents,
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