rbd: support reading parent page data

[~andy/linux] / drivers / block / rbd.c

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index ae223819bbf0e04cffd27b60a8a35abf6d9da2c5..2a0e9b81be483e1d57ac3c3facc7a457b89be2df 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -425,7 +425,8 @@ static void rbd_img_parent_read(struct rbd_obj_request *obj_request);
 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev);
 
 static int rbd_dev_refresh(struct rbd_device *rbd_dev);
-static int rbd_dev_v2_refresh(struct rbd_device *rbd_dev);
+static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev);
+static int rbd_dev_v2_header_info(struct rbd_device *rbd_dev);
 static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
                                        u64 snap_id);
 static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
@@ -788,7 +789,7 @@ static int rbd_header_from_disk(struct rbd_device *rbd_dev,
                 * Copy the names, and fill in each snapshot's id
                 * and size.
                 *
-                * Note that rbd_dev_v1_header_read() guarantees the
+                * Note that rbd_dev_v1_header_info() guarantees the
                 * ondisk buffer we're working with has
                 * snap_names_len bytes beyond the end of the
                 * snapshot id array, this memcpy() is safe.
@@ -2185,13 +2186,13 @@ rbd_img_obj_parent_read_full_callback(struct rbd_img_request *img_request)
        result = img_request->result;
        obj_size = img_request->length;
        xferred = img_request->xferred;
+       rbd_img_request_put(img_request);
 
-       rbd_dev = img_request->rbd_dev;
+       rbd_assert(orig_request->img_request);
+       rbd_dev = orig_request->img_request->rbd_dev;
        rbd_assert(rbd_dev);
        rbd_assert(obj_size == (u64)1 << rbd_dev->header.obj_order);
 
-       rbd_img_request_put(img_request);
-
        if (result)
                goto out_err;
 
@@ -2573,7 +2574,7 @@ static void rbd_img_parent_read(struct rbd_obj_request *obj_request)
        rbd_assert(obj_request_img_data_test(obj_request));
        rbd_assert(obj_request->img_request != NULL);
        rbd_assert(obj_request->result == (s32) -ENOENT);
-       rbd_assert(obj_request->type == OBJ_REQUEST_BIO);
+       rbd_assert(obj_request_type_valid(obj_request->type));
 
        rbd_dev = obj_request->img_request->rbd_dev;
        rbd_assert(rbd_dev->parent != NULL);
@@ -2589,8 +2590,12 @@ static void rbd_img_parent_read(struct rbd_obj_request *obj_request)
        rbd_obj_request_get(obj_request);
        img_request->obj_request = obj_request;
 
-       result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
-                                       obj_request->bio_list);
+       if (obj_request->type == OBJ_REQUEST_BIO)
+               result = rbd_img_request_fill(img_request, OBJ_REQUEST_BIO,
+                                               obj_request->bio_list);
+       else
+               result = rbd_img_request_fill(img_request, OBJ_REQUEST_PAGES,
+                                               obj_request->pages);
        if (result)
                goto out_err;
 
@@ -3050,7 +3055,7 @@ out:
  * return, the rbd_dev->header field will contain up-to-date
  * information about the image.
  */
-static int rbd_dev_v1_header_read(struct rbd_device *rbd_dev)
+static int rbd_dev_v1_header_info(struct rbd_device *rbd_dev)
 {
        struct rbd_image_header_ondisk *ondisk = NULL;
        u32 snap_count = 0;
@@ -3105,14 +3110,6 @@ out:
        return ret;
 }
 
-/*
- * only read the first part of the ondisk header, without the snaps info
- */
-static int rbd_dev_v1_refresh(struct rbd_device *rbd_dev)
-{
-       return rbd_dev_v1_header_read(rbd_dev);
-}
-
 /*
  * Clear the rbd device's EXISTS flag if the snapshot it's mapped to
  * has disappeared from the (just updated) snapshot context.
@@ -3141,9 +3138,9 @@ static int rbd_dev_refresh(struct rbd_device *rbd_dev)
        mapping_size = rbd_dev->mapping.size;
        mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
        if (rbd_dev->image_format == 1)
-               ret = rbd_dev_v1_refresh(rbd_dev);
+               ret = rbd_dev_v1_header_info(rbd_dev);
        else
-               ret = rbd_dev_v2_refresh(rbd_dev);
+               ret = rbd_dev_v2_header_info(rbd_dev);
 
        /* If it's a mapped snapshot, validate its EXISTS flag */
 
@@ -4013,12 +4010,19 @@ out:
        return snap_name;
 }
 
-static int rbd_dev_v2_refresh(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_header_info(struct rbd_device *rbd_dev)
 {
+       bool first_time = rbd_dev->header.object_prefix == NULL;
        int ret;
 
        down_write(&rbd_dev->header_rwsem);
 
+       if (first_time) {
+               ret = rbd_dev_v2_header_onetime(rbd_dev);
+               if (ret)
+                       goto out;
+       }
+
        ret = rbd_dev_v2_image_size(rbd_dev);
        if (ret)
                goto out;
@@ -4467,27 +4471,18 @@ static void rbd_dev_unprobe(struct rbd_device *rbd_dev)
        memset(header, 0, sizeof (*header));
 }
 
-static int rbd_dev_v1_probe(struct rbd_device *rbd_dev)
-{
-       return rbd_dev_v1_header_read(rbd_dev);
-}
-
-static int rbd_dev_v2_probe(struct rbd_device *rbd_dev)
+static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev)
 {
        int ret;
 
-       ret = rbd_dev_v2_image_size(rbd_dev);
-       if (ret)
-               goto out_err;
-
-       /* Get the object prefix (a.k.a. block_name) for the image */
-
        ret = rbd_dev_v2_object_prefix(rbd_dev);
        if (ret)
                goto out_err;
 
-       /* Get the and check features for the image */
-
+       /*
+        * Get the and check features for the image.  Currently the
+        * features are assumed to never change.
+        */
        ret = rbd_dev_v2_features(rbd_dev);
        if (ret)
                goto out_err;
@@ -4517,17 +4512,7 @@ static int rbd_dev_v2_probe(struct rbd_device *rbd_dev)
                if (ret < 0)
                        goto out_err;
        }
-
-       /* crypto and compression type aren't (yet) supported for v2 images */
-
-       rbd_dev->header.crypt_type = 0;
-       rbd_dev->header.comp_type = 0;
-
-       /* Get the snapshot context, plus the header version */
-
-       ret = rbd_dev_v2_snap_context(rbd_dev);
-       if (ret)
-               goto out_err;
+       /* No support for crypto and compression type format 2 images */
 
        return 0;
 out_err:
@@ -4714,9 +4699,9 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool read_only)
                goto out_header_name;
 
        if (rbd_dev->image_format == 1)
-               ret = rbd_dev_v1_probe(rbd_dev);
+               ret = rbd_dev_v1_header_info(rbd_dev);
        else
-               ret = rbd_dev_v2_probe(rbd_dev);
+               ret = rbd_dev_v2_header_info(rbd_dev);
        if (ret)
                goto err_out_watch;