rbd: get rid of RBD_OBJ_WRITE_{FLAT,GUARD}

In preparation for moving OSD request allocation and submission into
object request state machines, get rid of RBD_OBJ_WRITE_{FLAT,GUARD}.
We would need to start in a new state, whether the request is guarded
or not.  Unify them into RBD_OBJ_WRITE_OBJECT and pass guard info
through obj_req->flags.

While at it, make our ENOENT handling a little more precise: only hide
ENOENT when it is actually expected, that is on delete.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 7925b2fdde79222e709997f3b973b62f78496807..488da877a2bbb7ac54ed822a6e2cab5a44da510f 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -219,6 +219,9 @@ enum obj_operation_type {
        OBJ_OP_ZEROOUT,
 };
 
+#define RBD_OBJ_FLAG_DELETION                  (1U << 0)
+#define RBD_OBJ_FLAG_COPYUP_ENABLED            (1U << 1)
+
 enum rbd_obj_read_state {
        RBD_OBJ_READ_OBJECT = 1,
        RBD_OBJ_READ_PARENT,
@@ -250,8 +253,7 @@ enum rbd_obj_read_state {
  * even if there is a parent).
  */
 enum rbd_obj_write_state {
-       RBD_OBJ_WRITE_FLAT = 1,
-       RBD_OBJ_WRITE_GUARD,
+       RBD_OBJ_WRITE_OBJECT = 1,
        RBD_OBJ_WRITE_READ_FROM_PARENT,
        RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC,
        RBD_OBJ_WRITE_COPYUP_OPS,
@@ -259,6 +261,7 @@ enum rbd_obj_write_state {
 
 struct rbd_obj_request {
        struct ceph_object_extent ex;
+       unsigned int            flags;  /* RBD_OBJ_FLAG_* */
        union {
                enum rbd_obj_read_state  read_state;    /* for reads */
                enum rbd_obj_write_state write_state;   /* for writes */
@@ -1858,7 +1861,6 @@ static void __rbd_obj_setup_write(struct rbd_obj_request *obj_req,
 static int rbd_obj_setup_write(struct rbd_obj_request *obj_req)
 {
        unsigned int num_osd_ops, which = 0;
-       bool need_guard;
        int ret;
 
        /* reverse map the entire object onto the parent */
@@ -1866,23 +1868,24 @@ static int rbd_obj_setup_write(struct rbd_obj_request *obj_req)
        if (ret)
                return ret;
 
-       need_guard = rbd_obj_copyup_enabled(obj_req);
-       num_osd_ops = need_guard + count_write_ops(obj_req);
+       if (rbd_obj_copyup_enabled(obj_req))
+               obj_req->flags |= RBD_OBJ_FLAG_COPYUP_ENABLED;
+
+       num_osd_ops = count_write_ops(obj_req);
+       if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED)
+               num_osd_ops++; /* stat */
 
        obj_req->osd_req = rbd_osd_req_create(obj_req, num_osd_ops);
        if (!obj_req->osd_req)
                return -ENOMEM;
 
-       if (need_guard) {
+       if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED) {
                ret = __rbd_obj_setup_stat(obj_req, which++);
                if (ret)
                        return ret;
-
-               obj_req->write_state = RBD_OBJ_WRITE_GUARD;
-       } else {
-               obj_req->write_state = RBD_OBJ_WRITE_FLAT;
        }
 
+       obj_req->write_state = RBD_OBJ_WRITE_OBJECT;
        __rbd_obj_setup_write(obj_req, which);
        return 0;
 }
@@ -1921,11 +1924,15 @@ static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
        if (ret)
                return ret;
 
+       if (rbd_obj_is_entire(obj_req) && !obj_req->num_img_extents)
+               obj_req->flags |= RBD_OBJ_FLAG_DELETION;
+
        obj_req->osd_req = rbd_osd_req_create(obj_req, 1);
        if (!obj_req->osd_req)
                return -ENOMEM;
 
        if (rbd_obj_is_entire(obj_req) && !obj_req->num_img_extents) {
+               rbd_assert(obj_req->flags & RBD_OBJ_FLAG_DELETION);
                osd_req_op_init(obj_req->osd_req, 0, CEPH_OSD_OP_DELETE, 0);
        } else {
                dout("%s %p %llu~%llu -> %llu~%llu\n", __func__,
@@ -1936,7 +1943,7 @@ static int rbd_obj_setup_discard(struct rbd_obj_request *obj_req)
                                       off, next_off - off, 0, 0);
        }
 
-       obj_req->write_state = RBD_OBJ_WRITE_FLAT;
+       obj_req->write_state = RBD_OBJ_WRITE_OBJECT;
        rbd_osd_req_format_write(obj_req);
        return 0;
 }
@@ -1961,11 +1968,12 @@ static void __rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req,
 
        if (rbd_obj_is_entire(obj_req)) {
                if (obj_req->num_img_extents) {
-                       if (!rbd_obj_copyup_enabled(obj_req))
+                       if (!(obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED))
                                osd_req_op_init(obj_req->osd_req, which++,
                                                CEPH_OSD_OP_CREATE, 0);
                        opcode = CEPH_OSD_OP_TRUNCATE;
                } else {
+                       rbd_assert(obj_req->flags & RBD_OBJ_FLAG_DELETION);
                        osd_req_op_init(obj_req->osd_req, which++,
                                        CEPH_OSD_OP_DELETE, 0);
                        opcode = 0;
@@ -1986,7 +1994,6 @@ static void __rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req,
 static int rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req)
 {
        unsigned int num_osd_ops, which = 0;
-       bool need_guard;
        int ret;
 
        /* reverse map the entire object onto the parent */
@@ -1994,23 +2001,28 @@ static int rbd_obj_setup_zeroout(struct rbd_obj_request *obj_req)
        if (ret)
                return ret;
 
-       need_guard = rbd_obj_copyup_enabled(obj_req);
-       num_osd_ops = need_guard + count_zeroout_ops(obj_req);
+       if (rbd_obj_copyup_enabled(obj_req))
+               obj_req->flags |= RBD_OBJ_FLAG_COPYUP_ENABLED;
+       if (!obj_req->num_img_extents) {
+               if (rbd_obj_is_entire(obj_req))
+                       obj_req->flags |= RBD_OBJ_FLAG_DELETION;
+       }
+
+       num_osd_ops = count_zeroout_ops(obj_req);
+       if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED)
+               num_osd_ops++; /* stat */
 
        obj_req->osd_req = rbd_osd_req_create(obj_req, num_osd_ops);
        if (!obj_req->osd_req)
                return -ENOMEM;
 
-       if (need_guard) {
+       if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED) {
                ret = __rbd_obj_setup_stat(obj_req, which++);
                if (ret)
                        return ret;
-
-               obj_req->write_state = RBD_OBJ_WRITE_GUARD;
-       } else {
-               obj_req->write_state = RBD_OBJ_WRITE_FLAT;
        }
 
+       obj_req->write_state = RBD_OBJ_WRITE_OBJECT;
        __rbd_obj_setup_zeroout(obj_req, which);
        return 0;
 }
@@ -2617,6 +2629,11 @@ static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
        return 0;
 }
 
+/*
+ * The target object doesn't exist.  Read the data for the entire
+ * target object up to the overlap point (if any) from the parent,
+ * so we can use it for a copyup.
+ */
 static int rbd_obj_handle_write_guard(struct rbd_obj_request *obj_req)
 {
        struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
@@ -2649,22 +2666,24 @@ static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req, int *result)
        int ret;
 
        switch (obj_req->write_state) {
-       case RBD_OBJ_WRITE_GUARD:
+       case RBD_OBJ_WRITE_OBJECT:
                if (*result == -ENOENT) {
+                       if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED) {
+                               ret = rbd_obj_handle_write_guard(obj_req);
+                               if (ret) {
+                                       *result = ret;
+                                       return true;
+                               }
+                               return false;
+                       }
                        /*
-                        * The target object doesn't exist.  Read the data for
-                        * the entire target object up to the overlap point (if
-                        * any) from the parent, so we can use it for a copyup.
+                        * On a non-existent object:
+                        *   delete - -ENOENT, truncate/zero - 0
                         */
-                       ret = rbd_obj_handle_write_guard(obj_req);
-                       if (ret) {
-                               *result = ret;
-                               return true;
-                       }
-                       return false;
+                       if (obj_req->flags & RBD_OBJ_FLAG_DELETION)
+                               *result = 0;
                }
                /* fall through */
-       case RBD_OBJ_WRITE_FLAT:
        case RBD_OBJ_WRITE_COPYUP_OPS:
                return true;
        case RBD_OBJ_WRITE_READ_FROM_PARENT:
@@ -2695,31 +2714,20 @@ static bool rbd_obj_handle_write(struct rbd_obj_request *obj_req, int *result)
 }
 
 /*
- * Returns true if @obj_req is completed, or false otherwise.
+ * Return true if @obj_req is completed.
  */
 static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req,
                                     int *result)
 {
-       switch (obj_req->img_request->op_type) {
-       case OBJ_OP_READ:
-               return rbd_obj_handle_read(obj_req, result);
-       case OBJ_OP_WRITE:
-               return rbd_obj_handle_write(obj_req, result);
-       case OBJ_OP_DISCARD:
-       case OBJ_OP_ZEROOUT:
-               if (rbd_obj_handle_write(obj_req, result)) {
-                       /*
-                        * Hide -ENOENT from delete/truncate/zero -- discarding
-                        * a non-existent object is not a problem.
-                        */
-                       if (*result == -ENOENT)
-                               *result = 0;
-                       return true;
-               }
-               return false;
-       default:
-               BUG();
-       }
+       struct rbd_img_request *img_req = obj_req->img_request;
+       bool done;
+
+       if (!rbd_img_is_write(img_req))
+               done = rbd_obj_handle_read(obj_req, result);
+       else
+               done = rbd_obj_handle_write(obj_req, result);
+
+       return done;
 }
 
 static void rbd_obj_end_request(struct rbd_obj_request *obj_req, int result)