ceph: buffer decoding helpers

Helper for decoding into a ceph_buffer, and other misc decoding helpers
we will need.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/ceph/buffer.c b/fs/ceph/buffer.c
index 2576bd452cb8..b98086c7aeba 100644
--- a/fs/ceph/buffer.c
+++ b/fs/ceph/buffer.c
@@ -1,6 +1,7 @@
 
 #include "ceph_debug.h"
 #include "buffer.h"
+#include "decode.h"
 
 struct ceph_buffer *ceph_buffer_new(size_t len, gfp_t gfp)
 {
@@ -59,3 +60,19 @@ int ceph_buffer_alloc(struct ceph_buffer *b, int len, gfp_t gfp)
 	return 0;
 }
 
+int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end)
+{
+	size_t len;
+
+	ceph_decode_need(p, end, sizeof(u32), bad);
+	len = ceph_decode_32(p);
+	dout("decode_buffer len %d\n", (int)len);
+	ceph_decode_need(p, end, len, bad);
+	*b = ceph_buffer_new(len, GFP_NOFS);
+	if (!*b)
+		return -ENOMEM;
+	ceph_decode_copy(p, (*b)->vec.iov_base, len);
+	return 0;
+bad:
+	return -EINVAL;
+}