[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, 18 insertions, 7 deletions

diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index ea1f37d..24cb4c6 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -33,7 +33,7 @@ static int jffs2_do_setattr (struct inode *inode, struct iattr *iattr)
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 	struct jffs2_raw_inode *ri;
-	unsigned short dev;
+	union jffs2_device_node dev;
 	unsigned char *mdata = NULL;
 	int mdatalen = 0;
 	unsigned int ivalid;
@@ -51,9 +51,8 @@ static int jffs2_do_setattr (struct inode *inode, struct iattr *iattr)
 	   it out again with the appropriate data attached */
 	if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
 		/* For these, we don't actually need to read the old node */
-		dev = old_encode_dev(inode->i_rdev);
+		mdatalen = jffs2_encode_dev(&dev, inode->i_rdev);
 		mdata = (char *)&dev;
-		mdatalen = sizeof(dev);
 		D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of kdev_t\n", mdatalen));
 	} else if (S_ISLNK(inode->i_mode)) {
 		down(&f->sem);
@@ -232,6 +231,8 @@ void jffs2_read_inode (struct inode *inode)
 	struct jffs2_inode_info *f;
 	struct jffs2_sb_info *c;
 	struct jffs2_raw_inode latest_node;
+	union jffs2_device_node jdev;
+	dev_t rdev = 0;
 	int ret;
 
 	D1(printk(KERN_DEBUG "jffs2_read_inode(): inode->i_ino == %lu\n", inode->i_ino));
@@ -263,7 +264,6 @@ void jffs2_read_inode (struct inode *inode)
 	inode->i_blocks = (inode->i_size + 511) >> 9;
 
 	switch (inode->i_mode & S_IFMT) {
-		jint16_t rdev;
 
 	case S_IFLNK:
 		inode->i_op = &jffs2_symlink_inode_operations;
@@ -297,8 +297,16 @@ void jffs2_read_inode (struct inode *inode)
 	case S_IFBLK:
 	case S_IFCHR:
 		/* Read the device numbers from the media */
+		if (f->metadata->size != sizeof(jdev.old) &&
+		    f->metadata->size != sizeof(jdev.new)) {
+			printk(KERN_NOTICE "Device node has strange size %d\n", f->metadata->size);
+			up(&f->sem);
+			jffs2_do_clear_inode(c, f);
+			make_bad_inode(inode);
+			return;
+		}
 		D1(printk(KERN_DEBUG "Reading device numbers from flash\n"));
-		if (jffs2_read_dnode(c, f, f->metadata, (char *)&rdev, 0, sizeof(rdev)) < 0) {
+		if (jffs2_read_dnode(c, f, f->metadata, (char *)&jdev, 0, f->metadata->size) < 0) {
 			/* Eep */
 			printk(KERN_NOTICE "Read device numbers for inode %lu failed\n", (unsigned long)inode->i_ino);
 			up(&f->sem);
@@ -306,12 +314,15 @@ void jffs2_read_inode (struct inode *inode)
 			make_bad_inode(inode);
 			return;
 		}
+		if (f->metadata->size == sizeof(jdev.old))
+			rdev = old_decode_dev(je16_to_cpu(jdev.old));
+		else
+			rdev = new_decode_dev(je32_to_cpu(jdev.new));
 
 	case S_IFSOCK:
 	case S_IFIFO:
 		inode->i_op = &jffs2_file_inode_operations;
-		init_special_inode(inode, inode->i_mode,
-				   old_decode_dev((je16_to_cpu(rdev))));
+		init_special_inode(inode, inode->i_mode, rdev);
 		break;
 
 	default: