ext4: Don't treat a truncation of a zero-length file as replace-via-truncate

If a non-existent file is opened via O_WRONLY|O_CREAT|O_TRUNC, there's
no need to treat this as a true file truncation, so we shouldn't
activate the replace-via-truncate hueristic.

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

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2c10d34..875db94 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4127,7 +4127,8 @@ void ext4_truncate(struct inode *inode)
        if (!ext4_can_truncate(inode))
                return;
 
-       if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
+       if (ei->i_disksize && inode->i_size == 0 &&
+           !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
                ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
 
        if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {