android/android_kernel_asus_sm8350
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rbd: look up snapshot name in names buffer

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Rather than scanning the list of snapshot structures for it, scan
the snapshot context buffer containing snapshot names in order to
determine for a format 1 image the name associated with a given
snapshot id.

Pull out the part of rbd_dev_v1_snap_info() that does this scan into
a new function, _rbd_dev_v1_snap_name().  Have that function return
a dynamically-allocated copy of the name, and don't duplicate it in
rbd_dev_v1_snap_info().

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-04-30 00:44:33 -05:00 committed by Sage Weil
parent dedc81ea84
commit 9682fc6d3a
1 changed files with 30 additions and 10 deletions
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40
drivers/block/rbd.c
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@ -66,6 +66,8 @@
#define RBD_SNAP_HEAD_NAME "-"
#define BAD_SNAP_INDEX U32_MAX /* invalid index into snap array */
/* This allows a single page to hold an image name sent by OSD */
#define RBD_IMAGE_NAME_LEN_MAX (PAGE_SIZE - sizeof (__le32) - 1)
#define RBD_IMAGE_ID_LEN_MAX 64
@ -809,6 +811,33 @@ static int rbd_header_from_disk(struct rbd_image_header *header,
return -ENOMEM;
}
static const char *_rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, u32 which)
{
const char *snap_name;
rbd_assert(which < rbd_dev->header.snapc->num_snaps);
/* Skip over names until we find the one we are looking for */
snap_name = rbd_dev->header.snap_names;
while (which--)
snap_name += strlen(snap_name) + 1;
return kstrdup(snap_name, GFP_KERNEL);
}
static u32 rbd_dev_snap_index(struct rbd_device *rbd_dev, u64 snap_id)
{
struct ceph_snap_context *snapc = rbd_dev->header.snapc;
u32 which;
for (which = 0; which < snapc->num_snaps; which++)
if (snapc->snaps[which] == snap_id)
return which;
return BAD_SNAP_INDEX;
}
static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64 snap_id)
{
struct rbd_snap *snap;
@ -3421,17 +3450,8 @@ static const char *rbd_dev_v1_snap_info(struct rbd_device *rbd_dev, u32 which,
u64 *snap_size, u64 *snap_features)
{
const char *snap_name;
int i;
rbd_assert(which < rbd_dev->header.snapc->num_snaps);
/* Skip over names until we find the one we are looking for */
snap_name = rbd_dev->header.snap_names;
for (i = 0; i < which; i++)
snap_name += strlen(snap_name) + 1;
snap_name = kstrdup(snap_name, GFP_KERNEL);
snap_name = _rbd_dev_v1_snap_name(rbd_dev, which);
if (!snap_name)
return ERR_PTR(-ENOMEM);