patch-2.3.40 linux/fs/cramfs/cramfs.h

• Lines: 52
• Date: Tue Jan 11 10:24:58 2000
• Orig file: v2.3.39/linux/fs/cramfs/cramfs.h
• Orig date: Wed Dec 29 13:13:20 1999

diff -u --recursive --new-file v2.3.39/linux/fs/cramfs/cramfs.h linux/fs/cramfs/cramfs.h
@@ -5,17 +5,20 @@
 #define CRAMFS_SIGNATURE	"Compressed ROMFS"
 
 /*
- * Reasonably terse representation of the inode
- * data.. When the mode of the inode indicates
- * a special device node, the "offset" bits will
- * encode i_rdev. In other cases, "offset" points
- * to the ROM image for the actual file data
- * (whether that data be directory or compressed
- * file data depends on the inode type again)
+ * Reasonably terse representation of the inode data.
  */
 struct cramfs_inode {
 	u32 mode:16, uid:16;
+	/* SIZE for device files is i_rdev */
 	u32 size:24, gid:8;
+	/* NAMELEN is the length of the file name, divided by 4 and
+           rounded up.  (cramfs doesn't support hard links.) */
+	/* OFFSET: For symlinks and non-empty regular files, this
+	   contains the offset (divided by 4) of the file data in
+	   compressed form (starting with an array of block pointers;
+	   see README).  For non-empty directories it is the offset
+	   (divided by 4) of the inode of the first file in that
+	   directory.  For anything else, offset is zero. */
 	u32 namelen:6, offset:26;
 };
 
@@ -24,7 +27,8 @@
  */
 struct cramfs_super {
 	u32 magic;		/* 0x28cd3d45 - random number */
-	u32 size;		/* > offset, < 2**26 */
+	u32 size;		/* Not used.  mkcramfs currently
+                                   writes a constant 1<<16 here. */
 	u32 flags;		/* 0 */
 	u32 future;		/* 0 */
 	u8 signature[16];	/* "Compressed ROMFS" */
@@ -32,6 +36,13 @@
 	u8 name[16];		/* user-defined name */
 	struct cramfs_inode root;	/* Root inode data */
 };
+
+/*
+ * Valid values in super.flags.  Currently we refuse to mount
+ * if (flags & ~CRAMFS_SUPPORTED_FLAGS).  Maybe that should be
+ * changed to test super.future instead.
+ */
+#define CRAMFS_SUPPORTED_FLAGS (0xff)
 
 /* Uncompression interfaces to the underlying zlib */
 int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen);