[PATCH] ext3,4:fdatasync should skip metadata writeout

[Hisashi Hifumi]

Hi.
Currently fdatasync is identical to fsync in ext3,4.
I think fdatasync should skip journal flush in data=ordered and data=writeback 
mode
because this syscall is not required to synchronize the metadata.

My patch as below is similar to the approach of GFS2's fsync code(gfs2_fsync).

Thanks.

Signed-off-by :Hisashi Hifumi <[EMAIL PROTECTED]>

diff -Nrup linux-2.6.24-rc2.org/fs/ext3/fsync.c linux-2.6.24-rc2/fs/ext3/fsync.c
--- linux-2.6.24-rc2.org/fs/ext3/fsync.c        2007-11-07 06:57:46.000000000 
+0900
+++ linux-2.6.24-rc2/fs/ext3/fsync.c    2007-11-15 17:50:24.000000000 +0900
@@ -72,6 +72,9 @@ int ext3_sync_file(struct file * file, s
                goto out;
        }
 
+       if (datasync)
+               goto out;       
+
        /*
        * The VFS has written the file data.  If the inode is unaltered
        * then we need not start a commit.
diff -Nrup linux-2.6.24-rc2.org/fs/ext4/fsync.c linux-2.6.24-rc2/fs/ext4/fsync.c
--- linux-2.6.24-rc2.org/fs/ext4/fsync.c        2007-11-07 06:57:46.000000000 
+0900
+++ linux-2.6.24-rc2/fs/ext4/fsync.c    2007-11-15 17:50:54.000000000 +0900
@@ -72,6 +72,9 @@ int ext4_sync_file(struct file * file, s
                goto out;
        }
 
+       if (datasync)
+               goto out;
+
        /*
        * The VFS has written the file data.  If the inode is unaltered
        * then we need not start a commit.

patch-2624rc2-ext34-fdatasync.txt
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