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, 18 insertions, 0 deletions

diff --git a/fs/adfs/dir_fplus.c b/fs/adfs/dir_fplus.c
index a7f41da8115b..d9e3bee4e653 100644
--- a/fs/adfs/dir_fplus.c
+++ b/fs/adfs/dir_fplus.c
@@ -197,6 +197,24 @@ adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj)
                 if (obj->name[i] == '/')
                         obj->name[i] = '.';
 
+        obj->filetype = -1;
+
+        /*
+         * object is a file and is filetyped and timestamped?
+         * RISC OS 12-bit filetype is stored in load_address[19:8]
+         */
+        if ((0 == (obj->attr & ADFS_NDA_DIRECTORY)) &&
+                (0xfff00000 == (0xfff00000 & obj->loadaddr))) {
+                obj->filetype = (__u16) ((0x000fff00 & obj->loadaddr) >> 8);
+
+                /* optionally append the ,xyz hex filetype suffix */
+                if (ADFS_SB(dir->sb)->s_ftsuffix)
+                        obj->name_len +=
+                                append_filetype_suffix(
+                                        &obj->name[obj->name_len],
+                                        obj->filetype);
+        }
+
         dir->pos += 1;
         ret = 0;
 out: