Merge branch 'work.cramfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[sfrench/cifs-2.6.git] / include / uapi / linux / cramfs_fs.h

diff --git a/include/uapi/linux/cramfs_fs.h b/include/uapi/linux/cramfs_fs.h
index 5519504199e639ed261034b73c71ecfc48c3f83b..6713669aa2edd32c8e2b77cb563a9bfbb254c1e3 100644 (file)
--- a/include/uapi/linux/cramfs_fs.h
+++ b/include/uapi/linux/cramfs_fs.h
@@ -74,6 +74,7 @@ struct cramfs_super {
 #define CRAMFS_FLAG_HOLES              0x00000100      /* support for holes */
 #define CRAMFS_FLAG_WRONG_SIGNATURE    0x00000200      /* reserved */
 #define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET        0x00000400      /* shifted root fs */
+#define CRAMFS_FLAG_EXT_BLOCK_POINTERS 0x00000800      /* block pointer extensions */
 
 /*
  * Valid values in super.flags.  Currently we refuse to mount
@@ -83,7 +84,30 @@ struct cramfs_super {
 #define CRAMFS_SUPPORTED_FLAGS ( 0x000000ff \
                                | CRAMFS_FLAG_HOLES \
                                | CRAMFS_FLAG_WRONG_SIGNATURE \
-                               | CRAMFS_FLAG_SHIFTED_ROOT_OFFSET )
+                               | CRAMFS_FLAG_SHIFTED_ROOT_OFFSET \
+                               | CRAMFS_FLAG_EXT_BLOCK_POINTERS )
 
+/*
+ * Block pointer flags
+ *
+ * The maximum block offset that needs to be represented is roughly:
+ *
+ *   (1 << CRAMFS_OFFSET_WIDTH) * 4 +
+ *   (1 << CRAMFS_SIZE_WIDTH) / PAGE_SIZE * (4 + PAGE_SIZE)
+ *   = 0x11004000
+ *
+ * That leaves room for 3 flag bits in the block pointer table.
+ */
+#define CRAMFS_BLK_FLAG_UNCOMPRESSED   (1 << 31)
+#define CRAMFS_BLK_FLAG_DIRECT_PTR     (1 << 30)
+
+#define CRAMFS_BLK_FLAGS       ( CRAMFS_BLK_FLAG_UNCOMPRESSED \
+                               | CRAMFS_BLK_FLAG_DIRECT_PTR )
+
+/*
+ * Direct blocks are at least 4-byte aligned.
+ * Pointers to direct blocks are shifted down by 2 bits.
+ */
+#define CRAMFS_BLK_DIRECT_PTR_SHIFT    2
 
 #endif /* _UAPI__CRAMFS_H */