[ 135/171] rbd: expose the correct size of the device in sysfs

Greg Kroah-Hartman
2013-01-15T23:26:09Z

From: Josh Durgin <josh.durgin@dreamhost.com>

If an image was mapped to a snapshot, the size of the head version
would be shown. Protect capacity with header_rwsem, since it may
change.

Signed-off-by: Josh Durgin <josh.durgin@dreamhost.com>
Reviewed-by: Alex Elder <elder@inktank.com>
(cherry picked from commit a51aa0c042fa39946dd017d5f91a073300a71577)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/block/rbd.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1720,6 +1720,8 @@ static int __rbd_update_snaps(struct rbd
if (ret < 0)
return ret;

+ down_write(&rbd_dev->header_rwsem);
+
/* resized? */
if (rbd_dev->snap_id == CEPH_NOSNAP) {
sector_t size = (sector_t) h.image_size / SECTOR_SIZE;
@@ -1728,8 +1730,6 @@ static int __rbd_update_snaps(struct rbd
set_capacity(rbd_dev->disk, size);
}

- down_write(&rbd_dev->header_rwsem);
-
snap_seq = rbd_dev->header.snapc->seq;
if (rbd_dev->header.total_snaps &&
rbd_dev->header.snapc->snaps[0] == snap_seq)
@@ -1844,8 +1844,13 @@ static ssize_t rbd_size_show(struct devi
struct device_attribute *attr, char *buf)
{
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
+ sector_t size;
+
+ down_read(&rbd_dev->header_rwsem);
+ size = get_capacity(rbd_dev->disk);
+ up_read(&rbd_dev->header_rwsem);

- return sprintf(buf, "%llu\n", (unsigned long long)rbd_dev->header.image_size);
+ return sprintf(buf, "%llu\n", (unsigned long long) size * SECTOR_SIZE);
}

static ssize_t rbd_major_show(struct device *dev,