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

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Pull cramfs updates from Al Viro:
 "Nicolas Pitre's cramfs work"

* 'work.cramfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  cramfs: rehabilitate it
  cramfs: add mmap support
  cramfs: implement uncompressed and arbitrary data block positioning
  cramfs: direct memory access support
This commit is contained in:
Linus Torvalds 2017-11-17 13:20:41 -08:00
commit cbda1b270f
6 changed files with 586 additions and 71 deletions
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26
include/uapi/linux/cramfs_fs.h
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@ -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 */