[JFFS2] Support new device nodes

Device node major/minor numbers are just stored in the payload of a single
data node. Just extend that to 4 bytes and use new_encode_dev() for it.

We only use the 4-byte format if we _need_ to, if !old_valid_dev(foo).
This preserves backwards compatibility with older code as much as
possible. If we do make devices with major or minor numbers above 255, and
then mount the file system with the old code, it'll just read the first
two bytes and get the numbers wrong. If it comes to garbage-collect it,
it'll then write back those wrong numbers. But that's about the best we
can expect.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/jffs2/nodelist.h b/fs/jffs2/nodelist.h
index f6645afe88e4..24e0f28a8bac 100644
--- a/fs/jffs2/nodelist.h
+++ b/fs/jffs2/nodelist.h
@@ -268,6 +268,17 @@ static inline uint32_t ref_totlen(struct jffs2_sb_info *c,
 
 #define PAD(x) (((x)+3)&~3)
 
+static inline int jffs2_encode_dev(union jffs2_device_node *jdev, dev_t rdev)
+{
+	if (old_valid_dev(rdev)) {
+		jdev->old = cpu_to_je16(old_encode_dev(rdev));
+		return sizeof(jdev->old);
+	} else {
+		jdev->new = cpu_to_je32(new_encode_dev(rdev));
+		return sizeof(jdev->new);
+	}
+}
+
 static inline struct jffs2_inode_cache *jffs2_raw_ref_to_ic(struct jffs2_raw_node_ref *raw)
 {
 	while(raw->next_in_ino) {