From: Guangliang Zhao <lucienc...@gmail.com>

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

Signed-off-by: Guangliang Zhao <lucienc...@gmail.com>
Reviewed-by: Josh Durgin <josh.dur...@inktank.com>
Reviewed-by: Alex Elder <el...@linaro.org>
---
 drivers/block/rbd.c |   94 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 60 insertions(+), 34 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 282bfcd..c90a60a 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -209,6 +209,11 @@ 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 */
@@ -715,6 +720,18 @@ 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 "invalid op code";
+       }
+}
+
 /*
  * Get a ceph client with specific addr and configuration, if one does
  * not exist create it.  Either way, ceph_opts is consumed by this
@@ -1727,7 +1744,7 @@ 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)
 {
@@ -1735,16 +1752,14 @@ 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 */
 
@@ -1754,7 +1769,7 @@ 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;
@@ -1961,7 +1976,7 @@ 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;
@@ -1975,7 +1990,7 @@ 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 {
@@ -1992,8 +2007,7 @@ 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;
 }
@@ -2034,7 +2048,7 @@ 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;
 
@@ -2075,11 +2089,14 @@ 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)\n",
-                       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\n",
                        result, xferred);
                if (!img_request->result)
@@ -2157,10 +2174,10 @@ 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;
@@ -2168,7 +2185,6 @@ 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);
@@ -2230,15 +2246,21 @@ 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, obj_request);
                if (!osd_req)
                        goto out_unwind;
                obj_request->osd_req = osd_req;
                obj_request->callback = rbd_img_obj_callback;
 
-               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));
@@ -2255,7 +2277,7 @@ 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);
@@ -2625,7 +2647,7 @@ 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;
@@ -2848,7 +2870,7 @@ 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;
@@ -2912,7 +2934,7 @@ static int __rbd_dev_header_watch_sync(struct rbd_device 
*rbd_dev, bool start)
        if (!obj_request)
                goto out_cancel;
 
-       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)
                goto out_cancel;
@@ -3021,7 +3043,7 @@ 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;
@@ -3077,7 +3099,7 @@ static void rbd_request_fn(struct request_queue *q)
        int result;
 
        while ((rq = blk_fetch_request(q))) {
-               bool write_request = rq_data_dir(rq) == WRITE;
+               enum obj_operation_type op_type;
                struct rbd_img_request *img_request;
                struct ceph_snap_context *snapc = NULL;
                u64 offset;
@@ -3106,9 +3128,14 @@ static void rbd_request_fn(struct request_queue *q)
 
                spin_unlock_irq(q->queue_lock);
 
-               /* Disallow writes to a read-only device */
+               if (rq->cmd_flags & REQ_WRITE)
+                       op_type = OBJ_OP_WRITE;
+               else
+                       op_type = OBJ_OP_READ;
+
+               /* Only allow reads to a read-only device */
 
-               if (write_request) {
+               if (op_type != OBJ_OP_READ) {
                        result = -EROFS;
                        if (read_only)
                                goto end_request;
@@ -3153,7 +3180,7 @@ static void rbd_request_fn(struct request_queue *q)
 
                result = -ENOMEM;
                img_request = rbd_img_request_create(rbd_dev, offset, length,
-                                                       write_request, snapc);
+                                                       op_type, snapc);
                if (!img_request)
                        goto end_request;
 
@@ -3169,8 +3196,7 @@ end_request:
                spin_lock_irq(q->queue_lock);
                if (result < 0) {
                        rbd_warn(rbd_dev, "%s %llx at %llx result %d\n",
-                               write_request ? "write" : "read",
-                               length, offset, result);
+                               obj_op_name(op_type), length, offset, result);
                        if (snapc)
                                ceph_put_snap_context(snapc);
 
@@ -3267,7 +3293,7 @@ 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;
-- 
1.7.10.4

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