Re: PATCH: Relax fdatasync checks to IEEE Std 1003.1-2008

[Paul Ripke <stix%stix.id.au@localhost>]

On Mon, Mar 16, 2020 at 08:47:27AM -0400, Greg Troxel wrote:
>   [lots of test reports about fdatasync patch]
> 
> Thanks -- that's enough for me to be comfortable.
> and it's been proposed for more than long enough, with no adverse
> comments, so I'll commit it soonish.

fwiw, I missed a comment at the top of the function... fixed in
attached patch.

-- 
Paul Ripke
"Great minds discuss ideas, average minds discuss events, small minds
 discuss people."
-- Disputed: Often attributed to Eleanor Roosevelt. 1948.

diff --git a/lib/libc/sys/fdatasync.2 b/lib/libc/sys/fdatasync.2
index 3f12119f0dbb..20da609191f5 100644
--- a/lib/libc/sys/fdatasync.2
+++ b/lib/libc/sys/fdatasync.2
@@ -68,7 +68,7 @@ function will fail if:
 .It Bq Er EBADF
 The
 .Fa fd
-argument is not a valid file descriptor open for writing.
+argument is not a valid file descriptor.
 .It Bq Er EINVAL
 This implementation does not support synchronized I/O for this file.
 .It Bq Er ENOSYS
@@ -93,4 +93,4 @@ and outstanding I/O operations are not guaranteed to have been completed.
 The
 .Fn fdatasync
 function conforms to
-.St -p1003.1b-93 .
+.St -p1003.1-2008 .
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index d51beedbfca9..8cfe5abe6cf8 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -4059,8 +4059,7 @@ sys_fsync(struct lwp *l, const struct sys_fsync_args *uap, register_t *retval)
  * Sync a range of file data.  API modeled after that found in AIX.
  *
  * FDATASYNC indicates that we need only save enough metadata to be able
- * to re-read the written data.  Note we duplicate AIX's requirement that
- * the file be open for writing.
+ * to re-read the written data.
  */
 /* ARGSUSED */
 int
@@ -4141,10 +4140,6 @@ sys_fdatasync(struct lwp *l, const struct sys_fdatasync_args *uap, register_t *r
 	/* fd_getvnode() will use the descriptor for us */
 	if ((error = fd_getvnode(SCARG(uap, fd), &fp)) != 0)
 		return (error);
-	if ((fp->f_flag & FWRITE) == 0) {
-		fd_putfile(SCARG(uap, fd));
-		return (EBADF);
-	}
 	vp = fp->f_vnode;
 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 	error = VOP_FSYNC(vp, fp->f_cred, FSYNC_WAIT|FSYNC_DATAONLY, 0, 0);