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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-18 00:20:41 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-18 00:20:41 +0300
commitcbda1b270f7ac23665f25fa513d2a73ea7149cbe (patch)
treedf7d08c6dda69a8a664f8595109874e87f62129c /include/uapi
parentca5b857cb0f42986520abd9dbb0c2508067342b2 (diff)
parent8d59598c35dc1071e6c36f86c9a95f26dd08b4e5 (diff)
downloadlinux-cbda1b270f7ac23665f25fa513d2a73ea7149cbe.tar.xz
Merge branch 'work.cramfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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
Diffstat (limited to 'include/uapi')
-rw-r--r--include/uapi/linux/cramfs_fs.h26
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 */