adfs: add hexadecimal filetype suffix option

ADFS (FileCore) storage complies with the RISC OS filetype specification
(12 bits of file type information is stored in the file load address,
rather than using a file extension).  The existing driver largely ignores
this information and does not present it to the end user.

It is desirable that stored filetypes be made visible to the end user to
facilitate a precise copy of data and metadata from a hard disc (or image
thereof) into a RISC OS emulator (such as RPCEmu) or to a network share
which can be accessed by real Acorn systems.

This patch implements a per-mount filetype suffix option (use -o
ftsuffix=1) to present any filetype as a ,xyz hexadecimal suffix on each
file.  This type suffix is compatible with that used by RISC OS systems
that access network servers using NFS client software and by RPCemu's host
filing system.

Signed-off-by: Stuart Swales <stuart.swales.croftnuisk@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 18 deletions

diff --git a/fs/adfs/inode.c b/fs/adfs/inode.c
index 16d7ef2..92444e9 100644
--- a/fs/adfs/inode.c
+++ b/fs/adfs/inode.c
@@ -78,26 +78,13 @@ static const struct address_space_operations adfs_aops = {
 	.bmap		= _adfs_bmap
 };
 
-static inline unsigned int
-adfs_filetype(struct inode *inode)
-{
-	unsigned int type;
-
-	if (ADFS_I(inode)->stamped)
-		type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff;
-	else
-		type = (unsigned int) -1;
-
-	return type;
-}
-
 /*
  * Convert ADFS attributes and filetype to Linux permission.
  */
 static umode_t
 adfs_atts2mode(struct super_block *sb, struct inode *inode)
 {
-	unsigned int filetype, attr = ADFS_I(inode)->attr;
+	unsigned int attr = ADFS_I(inode)->attr;
 	umode_t mode, rmask;
 	struct adfs_sb_info *asb = ADFS_SB(sb);
 
@@ -106,9 +93,7 @@ adfs_atts2mode(struct super_block *sb, struct inode *inode)
 		return S_IFDIR | S_IXUGO | mode;
 	}
 
-	filetype = adfs_filetype(inode);
-
-	switch (filetype) {
+	switch (ADFS_I(inode)->filetype) {
 	case 0xfc0:	/* LinkFS */
 		return S_IFLNK|S_IRWXUGO;
 
@@ -277,7 +262,8 @@ adfs_iget(struct super_block *sb, struct object_info *obj)
 	ADFS_I(inode)->loadaddr  = obj->loadaddr;
 	ADFS_I(inode)->execaddr  = obj->execaddr;
 	ADFS_I(inode)->attr      = obj->attr;
-	ADFS_I(inode)->stamped	  = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
+	ADFS_I(inode)->filetype  = obj->filetype;
+	ADFS_I(inode)->stamped   = ((obj->loadaddr & 0xfff00000) == 0xfff00000);
 
 	inode->i_mode	 = adfs_atts2mode(sb, inode);
 	adfs_adfs2unix_time(&inode->i_mtime, inode);