[PATCH] fuse: add frsize to statfs reply

Add 'frsize' member to the statfs reply.

I'm not sure if sending f_fsid will ever be needed, but just in case leave
some space at the end of the structure, so less compatibility mess would be
required.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/fuse/inode.c

@@ -218,6 +218,7 @@ static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr
 {
 	stbuf->f_type    = FUSE_SUPER_MAGIC;
 	stbuf->f_bsize   = attr->bsize;
+	stbuf->f_frsize  = attr->frsize;
 	stbuf->f_blocks  = attr->blocks;
 	stbuf->f_bfree   = attr->bfree;
 	stbuf->f_bavail  = attr->bavail;
@@ -238,10 +239,12 @@ static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
 	if (!req)
 		return -EINTR;
 
+	memset(&outarg, 0, sizeof(outarg));
 	req->in.numargs = 0;
 	req->in.h.opcode = FUSE_STATFS;
 	req->out.numargs = 1;
-	req->out.args[0].size = sizeof(outarg);
+	req->out.args[0].size =
+		fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 	req->out.args[0].value = &outarg;
 	request_send(fc, req);
 	err = req->out.h.error;

include/linux/fuse.h

@@ -53,6 +53,9 @@ struct fuse_kstatfs {
 	__u64	ffree;
 	__u32	bsize;
 	__u32	namelen;
+	__u32	frsize;
+	__u32	padding;
+	__u32	spare[6];
 };
 
 #define FATTR_MODE	(1 << 0)
@@ -213,6 +216,8 @@ struct fuse_write_out {
 	__u32	padding;
 };
 
+#define FUSE_COMPAT_STATFS_SIZE 48
+
 struct fuse_statfs_out {
 	struct fuse_kstatfs st;
 };