Author: rmacklem
Date: Sun Nov 18 22:59:54 2018
New Revision: 340588
URL: https://svnweb.freebsd.org/changeset/base/340588
Log:
MFC: r339999
Fix NFS client vnode locking to avoid a crash during forced dismount.
A crash was reported where the crash occurred in nfs_advlock() when the
NFS_ISV4(vp) macro was being executed. This was caused by the vnode
being VI_DOOMED due to a forced dismount in progress.
This patch fixes the problem by locking the vnode before executing the
NFS_ISV4() macro.
PR: 232673
Modified:
stable/11/sys/fs/nfsclient/nfs_clvnops.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/fs/nfsclient/nfs_clvnops.c
==============================================================================
--- stable/11/sys/fs/nfsclient/nfs_clvnops.c Sun Nov 18 19:55:03 2018
(r340587)
+++ stable/11/sys/fs/nfsclient/nfs_clvnops.c Sun Nov 18 22:59:54 2018
(r340588)
@@ -3008,14 +3008,19 @@ nfs_advlock(struct vop_advlock_args *ap)
int ret, error = EOPNOTSUPP;
u_quad_t size;
+ ret = NFSVOPLOCK(vp, LK_SHARED);
+ if (ret != 0)
+ return (EBADF);
if (NFS_ISV4(vp) && (ap->a_flags & (F_POSIX | F_FLOCK)) != 0) {
- if (vp->v_type != VREG)
+ if (vp->v_type != VREG) {
+ NFSVOPUNLOCK(vp, 0);
return (EINVAL);
+ }
if ((ap->a_flags & F_POSIX) != 0)
cred = p->p_ucred;
else
cred = td->td_ucred;
- NFSVOPLOCK(vp, LK_EXCLUSIVE | LK_RETRY);
+ NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
if (vp->v_iflag & VI_DOOMED) {
NFSVOPUNLOCK(vp, 0);
return (EBADF);
@@ -3094,9 +3099,6 @@ nfs_advlock(struct vop_advlock_args *ap)
NFSVOPUNLOCK(vp, 0);
return (0);
} else if (!NFS_ISV4(vp)) {
- error = NFSVOPLOCK(vp, LK_SHARED);
- if (error)
- return (error);
if ((VFSTONFS(vp->v_mount)->nm_flag & NFSMNT_NOLOCKD) != 0) {
size = VTONFS(vp)->n_size;
NFSVOPUNLOCK(vp, 0);
@@ -3119,7 +3121,8 @@ nfs_advlock(struct vop_advlock_args *ap)
NFSVOPUNLOCK(vp, 0);
}
}
- }
+ } else
+ NFSVOPUNLOCK(vp, 0);
return (error);
}
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