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authorAlex Elder <elder@inktank.com>2013-05-06 09:51:29 -0500
committerAlex Elder <elder@inktank.com>2013-05-08 17:00:37 -0500
commit662518b128c27def65e9af4bea2b56a1e04b3251 (patch)
tree195365fca5ff452ad5364fb876f2b9a720e8ee5a /drivers/block/rbd.c
parentbb23e37acb2ae9604130c4819fb8ae0f784a3a2b (diff)
rbd: update in-core header directly
Now that rbd_header_from_disk() only fills in one-time fields once, we can extend it slightly so it releases the other fields before replacing their values. This way there's no need to pass a temporary buffer and then copy all the results in. Just use the rbd device header structure in rbd_header_from_disk() so its values get updated directly. Note that this means we need to take the header semaphore at the point we update things. So pass the rbd_dev rather than the address of its header as its first argument to rbd_header_from_disk(), and have it return an error code. As a result, rbd_dev_v1_header_read() does all the work, rbd_read_header() becomes unnecessary, and rbd_dev_v1_refresh() becomes a very simple wrapper. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Diffstat (limited to 'drivers/block/rbd.c')
-rw-r--r--drivers/block/rbd.c98
1 files changed, 27 insertions, 71 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index a3b6bf5e9ae..e4586f2e04c 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -730,9 +730,10 @@ static bool rbd_dev_ondisk_valid(struct rbd_image_header_ondisk *ondisk)
* Fill an rbd image header with information from the given format 1
* on-disk header.
*/
-static int rbd_header_from_disk(struct rbd_image_header *header,
+static int rbd_header_from_disk(struct rbd_device *rbd_dev,
struct rbd_image_header_ondisk *ondisk)
{
+ struct rbd_image_header *header = &rbd_dev->header;
bool first_time = header->object_prefix == NULL;
struct ceph_snap_context *snapc;
char *object_prefix = NULL;
@@ -802,6 +803,7 @@ static int rbd_header_from_disk(struct rbd_image_header *header,
/* We won't fail any more, fill in the header */
+ down_write(&rbd_dev->header_rwsem);
if (first_time) {
header->object_prefix = object_prefix;
header->obj_order = ondisk->options.order;
@@ -811,6 +813,10 @@ static int rbd_header_from_disk(struct rbd_image_header *header,
header->stripe_unit = 0;
header->stripe_count = 0;
header->features = 0;
+ } else {
+ ceph_put_snap_context(header->snapc);
+ kfree(header->snap_names);
+ kfree(header->snap_sizes);
}
/* The remaining fields always get updated (when we refresh) */
@@ -820,6 +826,14 @@ static int rbd_header_from_disk(struct rbd_image_header *header,
header->snap_names = snap_names;
header->snap_sizes = snap_sizes;
+ /* Make sure mapping size is consistent with header info */
+
+ if (rbd_dev->spec->snap_id == CEPH_NOSNAP || first_time)
+ if (rbd_dev->mapping.size != header->image_size)
+ rbd_dev->mapping.size = header->image_size;
+
+ up_write(&rbd_dev->header_rwsem);
+
return 0;
out_2big:
ret = -EIO;
@@ -3032,17 +3046,11 @@ out:
}
/*
- * Read the complete header for the given rbd device.
- *
- * Returns a pointer to a dynamically-allocated buffer containing
- * the complete and validated header. Caller can pass the address
- * of a variable that will be filled in with the version of the
- * header object at the time it was read.
- *
- * Returns a pointer-coded errno if a failure occurs.
+ * Read the complete header for the given rbd device. On successful
+ * return, the rbd_dev->header field will contain up-to-date
+ * information about the image.
*/
-static struct rbd_image_header_ondisk *
-rbd_dev_v1_header_read(struct rbd_device *rbd_dev)
+static int rbd_dev_v1_header_read(struct rbd_device *rbd_dev)
{
struct rbd_image_header_ondisk *ondisk = NULL;
u32 snap_count = 0;
@@ -3067,22 +3075,22 @@ rbd_dev_v1_header_read(struct rbd_device *rbd_dev)
size += names_size;
ondisk = kmalloc(size, GFP_KERNEL);
if (!ondisk)
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
ret = rbd_obj_read_sync(rbd_dev, rbd_dev->header_name,
0, size, ondisk);
if (ret < 0)
- goto out_err;
+ goto out;
if ((size_t)ret < size) {
ret = -ENXIO;
rbd_warn(rbd_dev, "short header read (want %zd got %d)",
size, ret);
- goto out_err;
+ goto out;
}
if (!rbd_dev_ondisk_valid(ondisk)) {
ret = -ENXIO;
rbd_warn(rbd_dev, "invalid header");
- goto out_err;
+ goto out;
}
names_size = le64_to_cpu(ondisk->snap_names_len);
@@ -3090,27 +3098,8 @@ rbd_dev_v1_header_read(struct rbd_device *rbd_dev)
snap_count = le32_to_cpu(ondisk->snap_count);
} while (snap_count != want_count);
- return ondisk;
-
-out_err:
- kfree(ondisk);
-
- return ERR_PTR(ret);
-}
-
-/*
- * reload the ondisk the header
- */
-static int rbd_read_header(struct rbd_device *rbd_dev,
- struct rbd_image_header *header)
-{
- struct rbd_image_header_ondisk *ondisk;
- int ret;
-
- ondisk = rbd_dev_v1_header_read(rbd_dev);
- if (IS_ERR(ondisk))
- return PTR_ERR(ondisk);
- ret = rbd_header_from_disk(header, ondisk);
+ ret = rbd_header_from_disk(rbd_dev, ondisk);
+out:
kfree(ondisk);
return ret;
@@ -3121,40 +3110,7 @@ static int rbd_read_header(struct rbd_device *rbd_dev,
*/
static int rbd_dev_v1_refresh(struct rbd_device *rbd_dev)
{
- int ret;
- struct rbd_image_header h;
-
- memset(&h, 0, sizeof (h));
- ret = rbd_read_header(rbd_dev, &h);
- if (ret < 0)
- return ret;
-
- down_write(&rbd_dev->header_rwsem);
-
- /* Update image size, and check for resize of mapped image */
- rbd_dev->header.image_size = h.image_size;
- if (rbd_dev->spec->snap_id == CEPH_NOSNAP)
- if (rbd_dev->mapping.size != rbd_dev->header.image_size)
- rbd_dev->mapping.size = rbd_dev->header.image_size;
-
- /* rbd_dev->header.object_prefix shouldn't change */
- kfree(rbd_dev->header.snap_sizes);
- kfree(rbd_dev->header.snap_names);
- /* osd requests may still refer to snapc */
- ceph_put_snap_context(rbd_dev->header.snapc);
-
- rbd_dev->header.image_size = h.image_size;
- rbd_dev->header.snapc = h.snapc;
- rbd_dev->header.snap_names = h.snap_names;
- rbd_dev->header.snap_sizes = h.snap_sizes;
- /* Free the extra copy of the object prefix */
- if (strcmp(rbd_dev->header.object_prefix, h.object_prefix))
- rbd_warn(rbd_dev, "object prefix changed (ignoring)");
- kfree(h.object_prefix);
-
- up_write(&rbd_dev->header_rwsem);
-
- return ret;
+ return rbd_dev_v1_header_read(rbd_dev);
}
/*
@@ -4517,7 +4473,7 @@ static int rbd_dev_v1_probe(struct rbd_device *rbd_dev)
/* Populate rbd image metadata */
- ret = rbd_read_header(rbd_dev, &rbd_dev->header);
+ ret = rbd_dev_v1_header_read(rbd_dev);
if (ret < 0)
goto out_err;