fat: Fix ATTR_RO for directory

[linux-2.6-omap-h63xx.git] / fs / fat / fat.h

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 2b8e94c3eef47f667e8abfa3ed3861fbb7c4b316..e9dce5d8e7a791b7a1f3f139a163f4dbeae7cfe1 100644 (file)
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -38,7 +38,8 @@ struct fat_mount_options {
                 flush:1,         /* write things quickly */
                 nocase:1,        /* Does this need case conversion? 0=need case conversion*/
                 usefree:1,       /* Use free_clusters for FAT32 */
-                tz_utc:1;        /* Filesystem timestamps are in UTC */
+                tz_utc:1,        /* Filesystem timestamps are in UTC */
+                rodir:1;         /* allow ATTR_RO for directory */
 };
 
 #define FAT_HASH_BITS  8
@@ -117,12 +118,60 @@ static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
        return container_of(inode, struct msdos_inode_info, vfs_inode);
 }
 
+/*
+ * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
+ * save ATTR_RO instead of ->i_mode.
+ *
+ * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
+ * bit, it's just used as flag for app.
+ */
+static inline int fat_mode_can_hold_ro(struct inode *inode)
+{
+       struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+       mode_t mask;
+
+       if (S_ISDIR(inode->i_mode)) {
+               if (!sbi->options.rodir)
+                       return 0;
+               mask = ~sbi->options.fs_dmask;
+       } else
+               mask = ~sbi->options.fs_fmask;
+
+       if (!(mask & S_IWUGO))
+               return 0;
+       return 1;
+}
+
+/* Convert attribute bits and a mask to the UNIX mode. */
+static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
+                                  u8 attrs, mode_t mode)
+{
+       if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
+               mode &= ~S_IWUGO;
+
+       if (attrs & ATTR_DIR)
+               return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
+       else
+               return (mode & ~sbi->options.fs_fmask) | S_IFREG;
+}
+
 /* Return the FAT attribute byte for this inode */
-static inline u8 fat_attr(struct inode *inode)
+static inline u8 fat_make_attrs(struct inode *inode)
+{
+       u8 attrs = MSDOS_I(inode)->i_attrs;
+       if (S_ISDIR(inode->i_mode))
+               attrs |= ATTR_DIR;
+       if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
+               attrs |= ATTR_RO;
+       return attrs;
+}
+
+static inline void fat_save_attrs(struct inode *inode, u8 attrs)
 {
-       return ((inode->i_mode & S_IWUGO) ? ATTR_NONE : ATTR_RO) |
-               (S_ISDIR(inode->i_mode) ? ATTR_DIR : ATTR_NONE) |
-               MSDOS_I(inode)->i_attrs;
+       if (fat_mode_can_hold_ro(inode))
+               MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
+       else
+               MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
 }
 
 static inline unsigned char fat_checksum(const __u8 *name)