On 07/05/2016 10:37 AM, Theodore Ts'o wrote:

On Tue, Jul 05, 2016 at 09:42:13AM -0400, Josef Bacik wrote:

quoted

quoted

diff --git a/fs/coredump.c b/fs/coredump.c
index 281b768000e6..9da7357773f0 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c

@@ -741,8 +741,10 @@ void do_coredump(const siginfo_t *siginfo)
 			goto close_fail;
 		if (!(cprm.file->f_mode & FMODE_CAN_WRITE))
 			goto close_fail;
-		if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
-			goto close_fail;
+		if (i_size_read(file_inode(cprm.file)) != 0) {
+			if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
+				goto close_fail;
+		}
 	}

 	/* get us an unshared descriptor table; almost always a no-op */

Omar, this probably breaks the case where we do
fallocate(FALLOC_FL_KEEP_SIZE), the i_size will be 0 but there will be
blocks to truncate.  Probably want to check i_blocks or something.  Thanks,

Sure, but this is in the coredump code; do we care there?  What are
the odds that someone will have fallocated blocks beyond i_size in a
file named "core"?  And if so, it's not like it's going to make the
coredump invalid or non-useful in any way.

Wow I totally didn't notice this was in coredump.c, I thought it was in ext4 
code because you said it failed regression tests, which I assumed were your ext4 
tests.  Ignore me.  Thanks,

Josef