svn commit: r300142 - in head/sys: kern sys ufs/ufs

[Konstantin Belousov]

Author: kib
Date: Wed May 18 12:03:57 2016
New Revision: 300142
URL: https://svnweb.freebsd.org/changeset/base/300142

Log:
  Ensure that ftruncate(2) is performed synchronously when file is
  opened in O_SYNC mode, at least for UFS.  This also handles
  truncation, done due to the O_SYNC | O_TRUNC flags combination to
  open(2), in synchronous way.
  
  Noted by:	bde
  Sponsored by:	The FreeBSD Foundation
  MFC after:	2 weeks

Modified:
  head/sys/kern/vfs_vnops.c
  head/sys/sys/vnode.h
  head/sys/ufs/ufs/ufs_vnops.c

Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c	Wed May 18 12:02:05 2016	(r300141)
+++ head/sys/kern/vfs_vnops.c	Wed May 18 12:03:57 2016	(r300142)
@@ -1314,6 +1314,8 @@ vn_truncate(struct file *fp, off_t lengt
 	if (error == 0) {
 		VATTR_NULL(&vattr);
 		vattr.va_size = length;
+		if ((fp->f_flag & O_FSYNC) != 0)
+			vattr.va_vaflags |= VA_SYNC;
 		error = VOP_SETATTR(vp, &vattr, fp->f_cred);
 	}
 out:

Modified: head/sys/sys/vnode.h
==============================================================================
--- head/sys/sys/vnode.h	Wed May 18 12:02:05 2016	(r300141)
+++ head/sys/sys/vnode.h	Wed May 18 12:03:57 2016	(r300142)
@@ -286,6 +286,7 @@ struct vattr {
  */
 #define	VA_UTIMES_NULL	0x01		/* utimes argument was NULL */
 #define	VA_EXCLUSIVE	0x02		/* exclusive create request */
+#define	VA_SYNC		0x04		/* O_SYNC truncation */
 
 /*
  * Flags for ioflag. (high 16 bits used to ask for read-ahead and

Modified: head/sys/ufs/ufs/ufs_vnops.c
==============================================================================
--- head/sys/ufs/ufs/ufs_vnops.c	Wed May 18 12:02:05 2016	(r300141)
+++ head/sys/ufs/ufs/ufs_vnops.c	Wed May 18 12:03:57 2016	(r300142)
@@ -625,7 +625,8 @@ ufs_setattr(ap)
 			 */
 			return (0);
 		}
-		if ((error = UFS_TRUNCATE(vp, vap->va_size, IO_NORMAL,
+		if ((error = UFS_TRUNCATE(vp, vap->va_size, IO_NORMAL |
+		    ((vap->va_vaflags & VA_SYNC) != 0 ? IO_SYNC : 0),
 		    cred)) != 0)
 			return (error);
 	}