[PATCH 07/16] rbd: dynamically allocate object prefix

[Alex Elder <elder@inktank.com>]

There is no need to impose a small limit the length of the object
prefix recorded for an rbd image in a struct rbd_image_header.
Remove the limitation by allocating space for the object prefix
dynamically.

Signed-off-by: Alex Elder <elder@inktank.com>
---
 drivers/block/rbd.c |   22 +++++++++++++++++-----
 1 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 57d264c..3aa0ca0 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -78,7 +78,7 @@
  */
 struct rbd_image_header {
 	u64 image_size;
-	char object_prefix[32];
+	char *object_prefix;
 	__u8 obj_order;
 	__u8 crypt_type;
 	__u8 comp_type;
@@ -518,8 +518,15 @@ static int rbd_header_from_disk(struct
rbd_image_header *header,
 		header->snap_names = NULL;
 		header->snap_sizes = NULL;
 	}
+
+	header->object_prefix = kmalloc(sizeof (ondisk->block_name) + 1,
+					gfp_flags);
+	if (!header->object_prefix)
+		goto err_sizes;
+
 	memcpy(header->object_prefix, ondisk->block_name,
 	       sizeof(ondisk->block_name));
+	header->object_prefix[sizeof (ondisk->block_name)] = '\0';

 	header->image_size = le64_to_cpu(ondisk->image_size);
 	header->obj_order = ondisk->options.order;
@@ -546,6 +553,8 @@ static int rbd_header_from_disk(struct
rbd_image_header *header,

 	return 0;

+err_sizes:
+	kfree(header->snap_sizes);
 err_names:
 	kfree(header->snap_names);
 err_snapc:
@@ -611,9 +620,10 @@ done:

 static void rbd_header_free(struct rbd_image_header *header)
 {
-	kfree(header->snapc);
-	kfree(header->snap_names);
+	kfree(header->object_prefix);
 	kfree(header->snap_sizes);
+	kfree(header->snap_names);
+	kfree(header->snapc);
 }

 /*
@@ -1711,15 +1721,17 @@ static int __rbd_refresh_header(struct
rbd_device *rbd_dev)
 		   if head moves */
 		follow_seq = 1;

-	kfree(rbd_dev->header.snapc);
-	kfree(rbd_dev->header.snap_names);
+	kfree(rbd_dev->header.object_prefix);
 	kfree(rbd_dev->header.snap_sizes);
+	kfree(rbd_dev->header.snap_names);
+	kfree(rbd_dev->header.snapc);

 	rbd_dev->header.total_snaps = h.total_snaps;
 	rbd_dev->header.snapc = h.snapc;
 	rbd_dev->header.snap_names = h.snap_names;
 	rbd_dev->header.snap_names_len = h.snap_names_len;
 	rbd_dev->header.snap_sizes = h.snap_sizes;
+	rbd_dev->header.object_prefix = h.object_prefix;
 	if (follow_seq)
 		rbd_dev->header.snapc->seq = rbd_dev->header.snapc->snaps[0];
 	else
-- 
1.7.5.4