CVS commit: src/sys/ufs/lfs

[Taylor R Campbell]

Module Name:    src
Committed By:   riastradh
Date:           Sun Feb 23 08:40:59 UTC 2020

Modified Files:
        src/sys/ufs/lfs: lfs_inode.c

Log Message:
In lfs_update, hold lfs_writer around lfs_vflush.

Otherwise, we might do

lfs_vflush
-> lfs_seglock
-> lfs_segwait(SEGM_CKP)
   -> lfs_writer_enter

which is the reverse of the lfs_writer -> lfs_seglock ordering.


To generate a diff of this commit:
cvs rdiff -u -r1.157 -r1.158 src/sys/ufs/lfs/lfs_inode.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/ufs/lfs/lfs_inode.c
diff -u src/sys/ufs/lfs/lfs_inode.c:1.157 src/sys/ufs/lfs/lfs_inode.c:1.158
--- src/sys/ufs/lfs/lfs_inode.c:1.157	Sat Jun 10 05:29:36 2017
+++ src/sys/ufs/lfs/lfs_inode.c	Sun Feb 23 08:40:58 2020
@@ -1,4 +1,4 @@
-/*	$NetBSD: lfs_inode.c,v 1.157 2017/06/10 05:29:36 maya Exp $	*/
+/*	$NetBSD: lfs_inode.c,v 1.158 2020/02/23 08:40:58 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2000, 2001, 2002, 2003 The NetBSD Foundation, Inc.
@@ -60,7 +60,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lfs_inode.c,v 1.157 2017/06/10 05:29:36 maya Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lfs_inode.c,v 1.158 2020/02/23 08:40:58 riastradh Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_quota.h"
@@ -133,6 +133,7 @@ lfs_update(struct vnode *vp, const struc
 	struct inode *ip;
 	struct lfs *fs = VFSTOULFS(vp->v_mount)->um_lfs;
 	int flags;
+	int error;
 
 	ASSERT_NO_SEGLOCK(fs);
 	if (vp->v_mount->mnt_flag & MNT_RDONLY)
@@ -175,7 +176,7 @@ lfs_update(struct vnode *vp, const struc
 			      vp->v_iflag | vp->v_vflag | vp->v_uflag,
 			      ip->i_state));
 			if (fs->lfs_dirops == 0)
-				lfs_flush_fs(fs, SEGM_SYNC);
+				break;
 			else
 				mtsleep(&fs->lfs_writer, PRIBIO+1, "lfs_fsync",
 					0, &lfs_lock);
@@ -183,8 +184,18 @@ lfs_update(struct vnode *vp, const struc
 			twice? */
 		}
 		--fs->lfs_diropwait;
+		fs->lfs_writer++;
+		if (vp->v_uflag & VU_DIROP) {
+			KASSERT(fs->lfs_dirops == 0);
+			lfs_flush_fs(fs, SEGM_SYNC);
+		}
+		mutex_exit(&lfs_lock);
+		error = lfs_vflush(vp);
+		mutex_enter(&lfs_lock);
+		if (--fs->lfs_writer == 0)
+			cv_broadcast(&fs->lfs_diropscv);
 		mutex_exit(&lfs_lock);
-		return lfs_vflush(vp);
+		return error;
 	}
 	return 0;
 }