[PATCH] ext4: uninitialised extent handling
Make it possible to add file preallocation support in future as an RO_COMPAT
feature by recognizing uninitialized extents as holes and limiting extent
length to keep the top bit of ee_len free for marking uninitialized extents.
Signed-off-by: Suparna Bhattacharya <suparna@in.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/ext4_fs_extents.h b/include/linux/ext4_fs_extents.h
index facc766..0eba0ac 100644
--- a/include/linux/ext4_fs_extents.h
+++ b/include/linux/ext4_fs_extents.h
@@ -141,6 +141,8 @@
#define EXT_MAX_BLOCK 0xffffffff
+#define EXT_MAX_LEN ((1UL << 15) - 1)
+
#define EXT_FIRST_EXTENT(__hdr__) \
((struct ext4_extent *) (((char *) (__hdr__)) + \