ext3: Add replace-on-truncate hueristics for data=writeback mode

In data=writeback mode, start an asynchronous flush when closing a
file which had been previously truncated down to zero.  This lowers
the probability of data loss in the case of applications that attempt
to replace a file using truncate.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h
index dd495b8c3091..d2630c56cb34 100644
--- a/include/linux/ext3_fs.h
+++ b/include/linux/ext3_fs.h
@@ -208,6 +208,7 @@ static inline __u32 ext3_mask_flags(umode_t mode, __u32 flags)
 #define EXT3_STATE_JDATA                0x00000001 /* journaled data exists */
 #define EXT3_STATE_NEW                  0x00000002 /* inode is newly created */
 #define EXT3_STATE_XATTR                0x00000004 /* has in-inode xattrs */
+#define EXT3_STATE_FLUSH_ON_CLOSE       0x00000008
 
 /* Used to pass group descriptor data when online resize is done */
 struct ext3_new_group_input {