rbd: extend the operation type

It could only handle the read and write operations now,
extend it for the coming discard support.

Signed-off-by: Guangliang Zhao <lucienchao@gmail.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 16eb247..d68c937 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -210,6 +210,11 @@ enum obj_request_type {
        OBJ_REQUEST_NODATA, OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES
 };
 
+enum obj_operation_type {
+       OBJ_OP_WRITE,
+       OBJ_OP_READ,
+};
+
 enum obj_req_flags {
        OBJ_REQ_DONE,           /* completion flag: not done = 0, done = 1 */
        OBJ_REQ_IMG_DATA,       /* object usage: standalone = 0, image = 1 */
@@ -785,6 +790,18 @@ static int parse_rbd_opts_token(char *c, void *private)
        return 0;
 }
 
+static char* obj_op_name(enum obj_operation_type op_type)
+{
+       switch (op_type) {
+       case OBJ_OP_READ:
+               return "read";
+       case OBJ_OP_WRITE:
+               return "write";
+       default:
+               return "???";
+       }
+}
+
 /*
  * Get a ceph client with specific addr and configuration, if one does
  * not exist create it.  Either way, ceph_opts is consumed by this
@@ -1823,7 +1840,7 @@ static void rbd_osd_req_format_write(struct rbd_obj_request *obj_request)
  */
 static struct ceph_osd_request *rbd_osd_req_create(
                                        struct rbd_device *rbd_dev,
-                                       bool write_request,
+                                       enum obj_operation_type op_type,
                                        unsigned int num_ops,
                                        struct rbd_obj_request *obj_request)
 {
@@ -1831,16 +1848,14 @@ static struct ceph_osd_request *rbd_osd_req_create(
        struct ceph_osd_client *osdc;
        struct ceph_osd_request *osd_req;
 
-       if (obj_request_img_data_test(obj_request)) {
+       if (obj_request_img_data_test(obj_request) && op_type == OBJ_OP_WRITE) {
                struct rbd_img_request *img_request = obj_request->img_request;
 
-               rbd_assert(write_request ==
-                               img_request_write_test(img_request));
-               if (write_request)
-                       snapc = img_request->snapc;
+               rbd_assert(img_request_write_test(img_request));
+               snapc = img_request->snapc;
        }
 
-       rbd_assert(num_ops == 1 || (write_request && num_ops == 2));
+       rbd_assert(num_ops == 1 || ((op_type == OBJ_OP_WRITE) && num_ops == 2));
 
        /* Allocate and initialize the request, for the num_ops ops */
 
@@ -1850,7 +1865,7 @@ static struct ceph_osd_request *rbd_osd_req_create(
        if (!osd_req)
                return NULL;    /* ENOMEM */
 
-       if (write_request)
+       if (op_type == OBJ_OP_WRITE)
                osd_req->r_flags = CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK;
        else
                osd_req->r_flags = CEPH_OSD_FLAG_READ;
@@ -2057,7 +2072,7 @@ static bool rbd_dev_parent_get(struct rbd_device *rbd_dev)
 static struct rbd_img_request *rbd_img_request_create(
                                        struct rbd_device *rbd_dev,
                                        u64 offset, u64 length,
-                                       bool write_request,
+                                       enum obj_operation_type op_type,
                                        struct ceph_snap_context *snapc)
 {
        struct rbd_img_request *img_request;
@@ -2071,7 +2086,7 @@ static struct rbd_img_request *rbd_img_request_create(
        img_request->offset = offset;
        img_request->length = length;
        img_request->flags = 0;
-       if (write_request) {
+       if (op_type == OBJ_OP_WRITE) {
                img_request_write_set(img_request);
                img_request->snapc = snapc;
        } else {
@@ -2088,8 +2103,7 @@ static struct rbd_img_request *rbd_img_request_create(
        kref_init(&img_request->kref);
 
        dout("%s: rbd_dev %p %s %llu/%llu -> img %p\n", __func__, rbd_dev,
-               write_request ? "write" : "read", offset, length,
-               img_request);
+               obj_op_name(op_type), offset, length, img_request);
 
        return img_request;
 }
@@ -2130,7 +2144,7 @@ static struct rbd_img_request *rbd_parent_request_create(
        rbd_dev = obj_request->img_request->rbd_dev;
 
        parent_request = rbd_img_request_create(rbd_dev->parent, img_offset,
-                                               length, false, NULL);
+                                               length, OBJ_OP_READ, NULL);
        if (!parent_request)
                return NULL;
 
@@ -2171,11 +2185,14 @@ static bool rbd_img_obj_end_request(struct rbd_obj_request *obj_request)
        result = obj_request->result;
        if (result) {
                struct rbd_device *rbd_dev = img_request->rbd_dev;
+               enum obj_operation_type op_type;
+
+               op_type = img_request_write_test(img_request) ? OBJ_OP_WRITE :
+                                                               OBJ_OP_READ;
 
                rbd_warn(rbd_dev, "%s %llx at %llx (%llx)",
-                       img_request_write_test(img_request) ? "write" : "read",
-                       obj_request->length, obj_request->img_offset,
-                       obj_request->offset);
+                       obj_op_name(op_type), obj_request->length,
+                       obj_request->img_offset, obj_request->offset);
                rbd_warn(rbd_dev, "  result %d xferred %x",
                        result, xferred);
                if (!img_request->result)
@@ -2254,10 +2271,10 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
        struct rbd_device *rbd_dev = img_request->rbd_dev;
        struct rbd_obj_request *obj_request = NULL;
        struct rbd_obj_request *next_obj_request;
-       bool write_request = img_request_write_test(img_request);
        struct bio *bio_list = NULL;
        unsigned int bio_offset = 0;
        struct page **pages = NULL;
+       enum obj_operation_type op_type;
        u64 img_offset;
        u64 resid;
        u16 opcode;
@@ -2265,7 +2282,6 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
        dout("%s: img %p type %d data_desc %p\n", __func__, img_request,
                (int)type, data_desc);
 
-       opcode = write_request ? CEPH_OSD_OP_WRITE : CEPH_OSD_OP_READ;
        img_offset = img_request->offset;
        resid = img_request->length;
        rbd_assert(resid > 0);
@@ -2327,16 +2343,24 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
                        pages += page_count;
                }
 
-               osd_req = rbd_osd_req_create(rbd_dev, write_request,
-                                            (write_request ? 2 : 1),
-                                            obj_request);
+               if (img_request_write_test(img_request)) {
+                       op_type = OBJ_OP_WRITE;
+                       opcode = CEPH_OSD_OP_WRITE;
+               } else {
+                       op_type = OBJ_OP_READ;
+                       opcode = CEPH_OSD_OP_READ;
+               }
+
+               osd_req = rbd_osd_req_create(rbd_dev, op_type,
+                                       (op_type == OBJ_OP_WRITE) ? 2 : 1,
+                                       obj_request);
                if (!osd_req)
                        goto out_unwind;
                obj_request->osd_req = osd_req;
                obj_request->callback = rbd_img_obj_callback;
                rbd_img_request_get(img_request);
 
-               if (write_request) {
+               if (op_type == OBJ_OP_WRITE) {
                        osd_req_op_alloc_hint_init(osd_req, which,
                                             rbd_obj_bytes(&rbd_dev->header),
                                             rbd_obj_bytes(&rbd_dev->header));
@@ -2353,7 +2377,7 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
                                        obj_request->pages, length,
                                        offset & ~PAGE_MASK, false, false);
 
-               if (write_request)
+               if (op_type == OBJ_OP_WRITE)
                        rbd_osd_req_format_write(obj_request);
                else
                        rbd_osd_req_format_read(obj_request);
@@ -2723,7 +2747,7 @@ static int rbd_img_obj_exists_submit(struct rbd_obj_request *obj_request)
 
        rbd_assert(obj_request->img_request);
        rbd_dev = obj_request->img_request->rbd_dev;
-       stat_request->osd_req = rbd_osd_req_create(rbd_dev, false, 1,
+       stat_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
                                                   stat_request);
        if (!stat_request->osd_req)
                goto out;
@@ -2947,7 +2971,7 @@ static int rbd_obj_notify_ack_sync(struct rbd_device *rbd_dev, u64 notify_id)
                return -ENOMEM;
 
        ret = -ENOMEM;
-       obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, 1,
+       obj_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
                                                  obj_request);
        if (!obj_request->osd_req)
                goto out;
@@ -3010,7 +3034,7 @@ static struct rbd_obj_request *rbd_obj_watch_request_helper(
        if (!obj_request)
                return ERR_PTR(-ENOMEM);
 
-       obj_request->osd_req = rbd_osd_req_create(rbd_dev, true, 1,
+       obj_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_WRITE, 1,
                                                  obj_request);
        if (!obj_request->osd_req) {
                ret = -ENOMEM;
@@ -3148,7 +3172,7 @@ static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
        obj_request->pages = pages;
        obj_request->page_count = page_count;
 
-       obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, 1,
+       obj_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
                                                  obj_request);
        if (!obj_request->osd_req)
                goto out;
@@ -3201,10 +3225,15 @@ static void rbd_handle_request(struct rbd_device *rbd_dev, struct request *rq)
        struct ceph_snap_context *snapc = NULL;
        u64 offset = (u64)blk_rq_pos(rq) << SECTOR_SHIFT;
        u64 length = blk_rq_bytes(rq);
-       bool wr = rq_data_dir(rq) == WRITE;
+       enum obj_operation_type op_type;
        u64 mapping_size;
        int result;
 
+       if (rq->cmd_flags & REQ_WRITE)
+               op_type = OBJ_OP_WRITE;
+       else
+               op_type = OBJ_OP_READ;
+
        /* Ignore/skip any zero-length requests */
 
        if (!length) {
@@ -3213,9 +3242,9 @@ static void rbd_handle_request(struct rbd_device *rbd_dev, struct request *rq)
                goto err_rq;
        }
 
-       /* Disallow writes to a read-only device */
+       /* Only reads are allowed to a read-only device */
 
-       if (wr) {
+       if (op_type != OBJ_OP_READ) {
                if (rbd_dev->mapping.read_only) {
                        result = -EROFS;
                        goto err_rq;
@@ -3245,7 +3274,7 @@ static void rbd_handle_request(struct rbd_device *rbd_dev, struct request *rq)
 
        down_read(&rbd_dev->header_rwsem);
        mapping_size = rbd_dev->mapping.size;
-       if (wr) {
+       if (op_type != OBJ_OP_READ) {
                snapc = rbd_dev->header.snapc;
                ceph_get_snap_context(snapc);
        }
@@ -3258,7 +3287,7 @@ static void rbd_handle_request(struct rbd_device *rbd_dev, struct request *rq)
                goto err_rq;
        }
 
-       img_request = rbd_img_request_create(rbd_dev, offset, length, wr,
+       img_request = rbd_img_request_create(rbd_dev, offset, length, op_type,
                                             snapc);
        if (!img_request) {
                result = -ENOMEM;
@@ -3281,7 +3310,7 @@ err_img_request:
 err_rq:
        if (result)
                rbd_warn(rbd_dev, "%s %llx at %llx result %d",
-                        wr ? "write" : "read", length, offset, result);
+                        obj_op_name(op_type), length, offset, result);
        if (snapc)
                ceph_put_snap_context(snapc);
        blk_end_request_all(rq, result);
@@ -3421,7 +3450,7 @@ static int rbd_obj_read_sync(struct rbd_device *rbd_dev,
        obj_request->pages = pages;
        obj_request->page_count = page_count;
 
-       obj_request->osd_req = rbd_osd_req_create(rbd_dev, false, 1,
+       obj_request->osd_req = rbd_osd_req_create(rbd_dev, OBJ_OP_READ, 1,
                                                  obj_request);
        if (!obj_request->osd_req)
                goto out;