diff options
Diffstat (limited to 'include/uapi/linux/cramfs_fs.h')
| -rw-r--r-- | include/uapi/linux/cramfs_fs.h | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/include/uapi/linux/cramfs_fs.h b/include/uapi/linux/cramfs_fs.h index 5519504199e6..6713669aa2ed 100644 --- 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 */ |