From 788e2df3b92e30f1fff74139bb53e68ec13fe2a5 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Thu, 17 Jan 2013 12:25:27 -0600 Subject: [PATCH] rbd: implement sync object read with new code Reimplement the synchronous read operation used for reading a version 1 header using the new request tracking code. Name the resulting function rbd_obj_read_sync() to better reflect that it's a full object operation, not an object request. To do this, implement a new OBJ_REQUEST_PAGES object request type. This implements a new mechanism to allow the caller to wait for completion for an rbd_obj_request by calling rbd_obj_request_wait(). This partially resolves: http://tracker.newdream.net/issues/3755 Signed-off-by: Alex Elder Reviewed-by: Josh Durgin --- drivers/block/rbd.c | 96 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 92 insertions(+), 4 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index c1bb649b4ad1..3f5eaea444a0 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -170,7 +170,7 @@ typedef void (*rbd_img_callback_t)(struct rbd_img_request *); struct rbd_obj_request; typedef void (*rbd_obj_callback_t)(struct rbd_obj_request *); -enum obj_request_type { OBJ_REQUEST_BIO }; /* More types to come */ +enum obj_request_type { OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES }; struct rbd_obj_request { const char *object_name; @@ -182,7 +182,13 @@ struct rbd_obj_request { u32 which; /* posn image request list */ enum obj_request_type type; - struct bio *bio_list; + union { + struct bio *bio_list; + struct { + struct page **pages; + u32 page_count; + }; + }; struct ceph_osd_request *osd_req; @@ -192,6 +198,7 @@ struct rbd_obj_request { atomic_t done; rbd_obj_callback_t callback; + struct completion completion; struct kref kref; }; @@ -1077,6 +1084,7 @@ static bool obj_request_type_valid(enum obj_request_type type) { switch (type) { case OBJ_REQUEST_BIO: + case OBJ_REQUEST_PAGES: return true; default: return false; @@ -1291,14 +1299,23 @@ static void rbd_img_request_complete(struct rbd_img_request *img_request) rbd_img_request_put(img_request); } +/* Caller is responsible for rbd_obj_request_destroy(obj_request) */ + +static int rbd_obj_request_wait(struct rbd_obj_request *obj_request) +{ + return wait_for_completion_interruptible(&obj_request->completion); +} + static void rbd_obj_request_complete(struct rbd_obj_request *obj_request) { if (obj_request->callback) obj_request->callback(obj_request); + else + complete_all(&obj_request->completion); } /* - * Request sync osd read + * Synchronously read a range from an object into a provided buffer */ static int rbd_req_sync_read(struct rbd_device *rbd_dev, const char *object_name, @@ -1556,6 +1573,11 @@ static struct ceph_osd_request *rbd_osd_req_create( /* osd client requires "num pages" even for bio */ osd_req->r_num_pages = calc_pages_for(offset, length); break; + case OBJ_REQUEST_PAGES: + osd_req->r_pages = obj_request->pages; + osd_req->r_num_pages = obj_request->page_count; + osd_req->r_page_alignment = offset & ~PAGE_MASK; + break; } if (write_request) { @@ -1616,6 +1638,7 @@ static struct rbd_obj_request *rbd_obj_request_create(const char *object_name, obj_request->type = type; INIT_LIST_HEAD(&obj_request->links); atomic_set(&obj_request->done, 0); + init_completion(&obj_request->completion); kref_init(&obj_request->kref); return obj_request; @@ -1639,6 +1662,11 @@ static void rbd_obj_request_destroy(struct kref *kref) if (obj_request->bio_list) bio_chain_put(obj_request->bio_list); break; + case OBJ_REQUEST_PAGES: + if (obj_request->pages) + ceph_release_page_vector(obj_request->pages, + obj_request->page_count); + break; } kfree(obj_request); @@ -1987,6 +2015,65 @@ static void rbd_free_disk(struct rbd_device *rbd_dev) put_disk(disk); } +static int rbd_obj_read_sync(struct rbd_device *rbd_dev, + const char *object_name, + u64 offset, u64 length, + char *buf, u64 *version) + +{ + struct ceph_osd_req_op *op; + struct rbd_obj_request *obj_request; + struct ceph_osd_client *osdc; + struct page **pages = NULL; + u32 page_count; + int ret; + + page_count = (u32) calc_pages_for(offset, length); + pages = ceph_alloc_page_vector(page_count, GFP_KERNEL); + if (IS_ERR(pages)) + ret = PTR_ERR(pages); + + ret = -ENOMEM; + obj_request = rbd_obj_request_create(object_name, offset, length, + OBJ_REQUEST_PAGES); + if (!obj_request) + goto out; + + obj_request->pages = pages; + obj_request->page_count = page_count; + + op = rbd_osd_req_op_create(CEPH_OSD_OP_READ, offset, length); + if (!op) + goto out; + obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, + obj_request, op); + rbd_osd_req_op_destroy(op); + if (!obj_request->osd_req) + goto out; + + osdc = &rbd_dev->rbd_client->client->osdc; + ret = rbd_obj_request_submit(osdc, obj_request); + if (ret) + goto out; + ret = rbd_obj_request_wait(obj_request); + if (ret) + goto out; + + ret = obj_request->result; + if (ret < 0) + goto out; + ret = ceph_copy_from_page_vector(pages, buf, 0, obj_request->xferred); + if (version) + *version = obj_request->version; +out: + if (obj_request) + rbd_obj_request_put(obj_request); + else + ceph_release_page_vector(pages, page_count); + + return ret; +} + /* * Read the complete header for the given rbd device. * @@ -2025,7 +2112,8 @@ rbd_dev_v1_header_read(struct rbd_device *rbd_dev, u64 *version) if (!ondisk) return ERR_PTR(-ENOMEM); - ret = rbd_req_sync_read(rbd_dev, rbd_dev->header_name, + (void) rbd_req_sync_read; /* avoid a warning */ + ret = rbd_obj_read_sync(rbd_dev, rbd_dev->header_name, 0, size, (char *) ondisk, version); -- 2.20.1