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>

6 files changed, 99 insertions, 26 deletions

diff --git a/Documentation/filesystems/adfs.txt b/Documentation/filesystems/adfs.txt
index 9e8811f92b84..5949766353f7 100644
--- a/Documentation/filesystems/adfs.txt
+++ b/Documentation/filesystems/adfs.txt
@@ -9,6 +9,9 @@ Mount options for ADFS
                 will be nnn.  Default 0700.
   othmask=nnn   The permission mask for ADFS 'other' permissions
                 will be nnn.  Default 0077.
+  ftsuffix=n    When ftsuffix=0, no file type suffix will be applied.
+                When ftsuffix=1, a hexadecimal suffix corresponding to
+                the RISC OS file type will be added.  Default 0.
 
 Mapping of ADFS permissions to Linux permissions
 ------------------------------------------------
@@ -55,3 +58,18 @@ Mapping of ADFS permissions to Linux permissions
 
   You can therefore tailor the permission translation to whatever you
   desire the permissions should be under Linux.
+
+RISC OS file type suffix
+------------------------
+
+  RISC OS file types are stored in bits 19..8 of the file load address.
+
+  To enable non-RISC OS systems to be used to store files without losing
+  file type information, a file naming convention was devised (initially
+  for use with NFS) such that a hexadecimal suffix of the form ,xyz
+  denoted the file type: e.g. BasicFile,ffb is a BASIC (0xffb) file.  This
+  naming convention is now also used by RISC OS emulators such as RPCEmu.
+
+  Mounting an ADFS disc with option ftsuffix=1 will cause appropriate file
+  type suffixes to be appended to file names read from a directory.  If the
+  ftsuffix option is zero or omitted, no file type suffixes will be added.
diff --git a/fs/adfs/adfs.h b/fs/adfs/adfs.h
index 58588ddb178c..a8a58d864f96 100644
--- a/fs/adfs/adfs.h
+++ b/fs/adfs/adfs.h
@@ -50,6 +50,7 @@ struct adfs_sb_info {
         gid_t           s_gid;          /* owner gid                             */
         umode_t         s_owner_mask;   /* ADFS owner perm -> unix perm          */
         umode_t         s_other_mask;   /* ADFS other perm -> unix perm          */
+        int             s_ftsuffix;     /* ,xyz hex filetype suffix option */
 
         __u32           s_ids_per_zone; /* max. no ids in one zone               */
         __u32           s_idlen;        /* length of ID in map                   */
@@ -93,7 +94,7 @@ struct adfs_dir {
 /*
  * This is the overall maximum name length
  */
-#define ADFS_MAX_NAME_LEN       256
+#define ADFS_MAX_NAME_LEN       (256 + 4) /* +4 for ,xyz hex filetype suffix */
 struct object_info {
         __u32           parent_id;              /* parent object id     */
         __u32           file_id;                /* object id            */
@@ -101,10 +102,26 @@ struct object_info {
         __u32           execaddr;               /* execution address    */
         __u32           size;                   /* size                 */
         __u8            attr;                   /* RISC OS attributes   */
-        unsigned char   name_len;               /* name length          */
+        unsigned int    name_len;               /* name length          */
         char            name[ADFS_MAX_NAME_LEN];/* file name            */
+
+        /* RISC OS file type (12-bit: derived from loadaddr) */
+        __u16           filetype;
 };
 
+/* RISC OS 12-bit filetype converts to ,xyz hex filename suffix */
+static inline int append_filetype_suffix(char *buf, __u16 filetype)
+{
+        if (filetype == -1)
+                return 0;
+
+        *buf++ = ',';
+        *buf++ = hex_asc_lo(filetype >> 8);
+        *buf++ = hex_asc_lo(filetype >> 4);
+        *buf++ = hex_asc_lo(filetype >> 0);
+        return 4;
+}
+
 struct adfs_dir_ops {
         int     (*read)(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir);
         int     (*setpos)(struct adfs_dir *dir, unsigned int fpos);
diff --git a/fs/adfs/dir_f.c b/fs/adfs/dir_f.c
index bafc71222e25..4bbe853ee50a 100644
--- a/fs/adfs/dir_f.c
+++ b/fs/adfs/dir_f.c
@@ -52,7 +52,6 @@ static inline int adfs_readname(char *buf, char *ptr, int maxlen)
                         *buf++ = *ptr;
                 ptr++;
         }
-        *buf = '\0';
 
         return buf - old_buf;
 }
@@ -208,7 +207,8 @@ release_buffers:
  * convert a disk-based directory entry to a Linux ADFS directory entry
  */
 static inline void
-adfs_dir2obj(struct object_info *obj, struct adfs_direntry *de)
+adfs_dir2obj(struct adfs_dir *dir, struct object_info *obj,
+        struct adfs_direntry *de)
 {
         obj->name_len = adfs_readname(obj->name, de->dirobname, ADFS_F_NAME_LEN);
         obj->file_id  = adfs_readval(de->dirinddiscadd, 3);
@@ -216,6 +216,23 @@ adfs_dir2obj(struct object_info *obj, struct adfs_direntry *de)
         obj->execaddr = adfs_readval(de->direxec, 4);
         obj->size     = adfs_readval(de->dirlen,  4);
         obj->attr     = de->newdiratts;
+        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);
+        }
 }
 
 /*
@@ -260,7 +277,7 @@ __adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj)
         if (!de.dirobname[0])
                 return -ENOENT;
 
-        adfs_dir2obj(obj, &de);
+        adfs_dir2obj(dir, obj, &de);
 
         return 0;
 }
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:
diff --git a/fs/adfs/inode.c b/fs/adfs/inode.c
index 16d7ef2dffe1..92444e94f842 100644
--- a/fs/adfs/inode.c
+++ b/fs/adfs/inode.c
@@ -78,26 +78,13 @@ static const struct address_space_operations adfs_aops = {