1 files changed, 23 insertions, 40 deletions

diff --git a/fs/adfs/inode.c b/fs/adfs/inode.c
index 09fe40198d1c..d5250c5aae21 100644
--- a/fs/adfs/inode.c
+++ b/fs/adfs/inode.c
@@ -72,32 +72,18 @@ static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
 static const struct address_space_operations adfs_aops = {
         .readpage       = adfs_readpage,
         .writepage      = adfs_writepage,
-        .sync_page      = block_sync_page,
         .write_begin    = adfs_write_begin,
         .write_end      = generic_write_end,
         .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 +92,7 @@ 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;
 
@@ -174,50 +158,48 @@ adfs_mode2atts(struct super_block *sb, struct inode *inode)
 
 /*
  * Convert an ADFS time to Unix time.  ADFS has a 40-bit centi-second time
- * referenced to 1 Jan 1900 (til 2248)
+ * referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds
+ * of time to convert from RISC OS epoch to Unix epoch.
  */
 static void
 adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
 {
         unsigned int high, low;
+        /* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since
+         * 01 Jan 1900 00:00:00 (RISC OS epoch)
+         */
+        static const s64 nsec_unix_epoch_diff_risc_os_epoch =
+                                                        2208988800000000000LL;
+        s64 nsec;
 
         if (ADFS_I(inode)->stamped == 0)
                 goto cur_time;
 
-        high = ADFS_I(inode)->loadaddr << 24;
-        low  = ADFS_I(inode)->execaddr;
+        high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */
+        low  = ADFS_I(inode)->execaddr;    /* bottom 32 bits of timestamp */
 
-        high |= low >> 8;
-        low  &= 255;
+        /* convert 40-bit centi-seconds to 32-bit seconds
+         * going via nanoseconds to retain precision
+         */
+        nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */
 
         /* Files dated pre  01 Jan 1970 00:00:00. */
-        if (high < 0x336e996a)
+        if (nsec < nsec_unix_epoch_diff_risc_os_epoch)
                 goto too_early;
 
-        /* Files dated post 18 Jan 2038 03:14:05. */
-        if (high >= 0x656e9969)
-                goto too_late;
+        /* convert from RISC OS to Unix epoch */
+        nsec -= nsec_unix_epoch_diff_risc_os_epoch;
 
-        /* discard 2208988800 (0x336e996a00) seconds of time */
-        high -= 0x336e996a;
-
-        /* convert 40-bit centi-seconds to 32-bit seconds */
-        tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
-        tv->tv_nsec = 0;
+        *tv = ns_to_timespec(nsec);
         return;
 
  cur_time:
-        *tv = CURRENT_TIME_SEC;
+        *tv = CURRENT_TIME;
         return;
 
  too_early:
         tv->tv_sec = tv->tv_nsec = 0;
         return;
-
- too_late:
-        tv->tv_sec = 0x7ffffffd;
-        tv->tv_nsec = 0;
-        return;
 }
 
 /*
@@ -279,7 +261,8 @@ 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);