Date: Tue, 9 Dec 2014 10:00:47 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r275638 - in head/sys: fs/msdosfs kern Message-ID: <201412091000.sB9A0l9Z054543@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: kib Date: Tue Dec 9 10:00:47 2014 New Revision: 275638 URL: https://svnweb.freebsd.org/changeset/base/275638 Log: Do not call VFS_SYNC() before VFS_UNMOUNT() for forced unmount. Since VFS does not/cannot stop writes, sync might run indefinitely, or be a wrong thing to do at all. E. g. NFS ignores VFS_SYNC() for forced unmounts, since non-responding server does not allow sync to finish. On the other hand, filesystems can and do stop writes using fs-specific facilities, and should already fully flush caches in VFS_UNMOUNT() due to the race. Adjust msdosfs tp sync in unmount for forced call, to accomodate the new behaviour. Note that it is still racy, since writes are not stopped. Discussed with: avg, bjk, mckusick Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 3 weeks Modified: head/sys/fs/msdosfs/msdosfs_vfsops.c head/sys/kern/vfs_mount.c Modified: head/sys/fs/msdosfs/msdosfs_vfsops.c ============================================================================== --- head/sys/fs/msdosfs/msdosfs_vfsops.c Tue Dec 9 09:36:28 2014 (r275637) +++ head/sys/fs/msdosfs/msdosfs_vfsops.c Tue Dec 9 10:00:47 2014 (r275638) @@ -797,11 +797,15 @@ msdosfs_unmount(struct mount *mp, int mn int error, flags; flags = 0; - if (mntflags & MNT_FORCE) + error = msdosfs_sync(mp, MNT_WAIT); + if ((mntflags & MNT_FORCE) != 0) { flags |= FORCECLOSE; + } else if (error != 0) { + return (error); + } error = vflush(mp, 0, flags, curthread); - if (error && error != ENXIO) - return error; + if (error != 0 && error != ENXIO) + return (error); pmp = VFSTOMSDOSFS(mp); if ((pmp->pm_flags & MSDOSFSMNT_RONLY) == 0) { error = markvoldirty(pmp, 0); Modified: head/sys/kern/vfs_mount.c ============================================================================== --- head/sys/kern/vfs_mount.c Tue Dec 9 09:36:28 2014 (r275637) +++ head/sys/kern/vfs_mount.c Tue Dec 9 10:00:47 2014 (r275638) @@ -1305,8 +1305,8 @@ dounmount(mp, flags, td) } vput(fsrootvp); } - if (((mp->mnt_flag & MNT_RDONLY) || - (error = VFS_SYNC(mp, MNT_WAIT)) == 0) || (flags & MNT_FORCE) != 0) + if ((mp->mnt_flag & MNT_RDONLY) != 0 || (flags & MNT_FORCE) != 0 || + (error = VFS_SYNC(mp, MNT_WAIT)) == 0) error = VFS_UNMOUNT(mp, flags); vn_finished_write(mp); /*
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201412091000.sB9A0l9Z054543>