From 83154f853d9ca39deb1add01e032aff1f0678514 Mon Sep 17 00:00:00 2001
From: tegge <tegge@FreeBSD.org>
Date: Tue, 26 Sep 2006 04:12:49 +0000
Subject: Use mount interlock to protect all changes to mnt_flag and
 mnt_kern_flag. This eliminates a race where MNT_UPDATE flag could be lost
 when nmount() raced against sync(), sync_fsync() or quotactl().

---
 sys/fs/msdosfs/msdosfs_vfsops.c | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'sys/fs/msdosfs/msdosfs_vfsops.c')

diff --git a/sys/fs/msdosfs/msdosfs_vfsops.c b/sys/fs/msdosfs/msdosfs_vfsops.c
index a485632..c0963cb 100644
--- a/sys/fs/msdosfs/msdosfs_vfsops.c
+++ b/sys/fs/msdosfs/msdosfs_vfsops.c
@@ -706,7 +706,9 @@ mountmsdosfs(devvp, mp, td)
 	mp->mnt_data = (qaddr_t) pmp;
 	mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
 	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
+	MNT_ILOCK(mp);
 	mp->mnt_flag |= MNT_LOCAL;
+	MNT_IUNLOCK(mp);
 
 #ifdef MSDOSFS_LARGE
 	msdosfs_fileno_init(mp);
@@ -798,7 +800,9 @@ msdosfs_unmount(mp, mntflags, td)
 #endif
 	free(pmp, M_MSDOSFSMNT);
 	mp->mnt_data = (qaddr_t)0;
+	MNT_ILOCK(mp);
 	mp->mnt_flag &= ~MNT_LOCAL;
+	MNT_IUNLOCK(mp);
 	return (error);
 }
 
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