The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=161e9a97363d17caf0b47983b28a37f3f59f9978
commit 161e9a97363d17caf0b47983b28a37f3f59f9978
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2021-07-17 22:56:47 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2021-07-27 16:58:47 +0000
nullfs: provide custom null_advlock bypass
The advlock VOP takes the vnode unlocked, which makes the normal bypass
function racy. Same as null_pgcache_read(), nullfs implementation needs
to take interlock and reference lower vnode under it.
Reported and tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31310
---
sys/fs/nullfs/null_vnops.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/sys/fs/nullfs/null_vnops.c b/sys/fs/nullfs/null_vnops.c
index 56973530fd95..0d5092f5e33d 100644
--- a/sys/fs/nullfs/null_vnops.c
+++ b/sys/fs/nullfs/null_vnops.c
@@ -980,6 +980,28 @@ null_read_pgcache(struct vop_read_pgcache_args *ap)
return (error);
}
+static int
+null_advlock(struct vop_advlock_args *ap)
+{
+ struct vnode *lvp, *vp;
+ struct null_node *xp;
+ int error;
+
+ vp = ap->a_vp;
+ VI_LOCK(vp);
+ xp = VTONULL(vp);
+ if (xp == NULL) {
+ VI_UNLOCK(vp);
+ return (EBADF);
+ }
+ lvp = xp->null_lowervp;
+ vref(lvp);
+ VI_UNLOCK(vp);
+ error = VOP_ADVLOCK(lvp, ap->a_id, ap->a_op, ap->a_fl, ap->a_flags);
+ vrele(lvp);
+ return (error);
+}
+
/*
* Avoid standard bypass, since lower dvp and vp could be no longer
* valid after vput().
@@ -1052,6 +1074,7 @@ struct vop_vector null_vnodeops = {
.vop_bypass = null_bypass,
.vop_access = null_access,
.vop_accessx = null_accessx,
+ .vop_advlock = null_advlock,
.vop_advlockpurge = vop_stdadvlockpurge,
.vop_bmap = VOP_EOPNOTSUPP,
.vop_stat = null_stat,
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