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authorKonstantin Belousov <kib@FreeBSD.org>2021-01-24 13:22:48 +0000
committerKonstantin Belousov <kib@FreeBSD.org>2021-02-12 01:02:20 +0000
commite4aaf35ab54958f74409790fa2b7df8c2d230cee (patch)
treed9f6ad64a274e27e58f56dd936f7bf533f9ba28b
parent49c117c193768b10f5fb1c5e4d6b88300cfbcdd6 (diff)
downloadsrc-e4aaf35ab54958f74409790fa2b7df8c2d230cee.tar.gz
src-e4aaf35ab54958f74409790fa2b7df8c2d230cee.zip
nullfs: provide special bypass for VOP_VPUT_PAIR
Generic bypass cannot understand the rules of liveness for the VOP. Reviewed by: chs, mckusick Tested by: pho MFC after: 2 weeks Sponsored by: The FreeBSD Foundation
-rw-r--r--sys/fs/nullfs/null_vnops.c49
1 files changed, 49 insertions, 0 deletions
diff --git a/sys/fs/nullfs/null_vnops.c b/sys/fs/nullfs/null_vnops.c
index 1de0cdfca9ac..45065e0be7b5 100644
--- a/sys/fs/nullfs/null_vnops.c
+++ b/sys/fs/nullfs/null_vnops.c
@@ -968,6 +968,54 @@ null_read_pgcache(struct vop_read_pgcache_args *ap)
}
/*
+ * Avoid standard bypass, since lower dvp and vp could be no longer
+ * valid after vput().
+ */
+static int
+null_vput_pair(struct vop_vput_pair_args *ap)
+{
+ struct mount *mp;
+ struct vnode *dvp, *ldvp, *lvp, *vp, *vp1, **vpp;
+ int error, res;
+
+ dvp = ap->a_dvp;
+ ldvp = NULLVPTOLOWERVP(dvp);
+ vref(ldvp);
+
+ vpp = ap->a_vpp;
+ vp = NULL;
+ lvp = NULL;
+ if (vpp != NULL) {
+ vp = *vpp;
+ if (vp != NULL) {
+ vhold(vp);
+ mp = vp->v_mount;
+ lvp = NULLVPTOLOWERVP(vp);
+ if (ap->a_unlock_vp)
+ vref(lvp);
+ }
+ }
+
+ res = VOP_VPUT_PAIR(ldvp, &lvp, ap->a_unlock_vp);
+
+ /* lvp might have been unlocked and vp reclaimed */
+ if (vp != NULL) {
+ if (!ap->a_unlock_vp && vp->v_vnlock != lvp->v_vnlock) {
+ error = null_nodeget(mp, lvp, &vp1);
+ if (error == 0) {
+ vput(vp);
+ *vpp = vp1;
+ }
+ }
+ if (ap->a_unlock_vp)
+ vrele(vp);
+ vdrop(vp);
+ }
+ vrele(dvp);
+ return (res);
+}
+
+/*
* Global vfs data structures
*/
struct vop_vector null_vnodeops = {
@@ -997,5 +1045,6 @@ struct vop_vector null_vnodeops = {
.vop_vptocnp = null_vptocnp,
.vop_vptofh = null_vptofh,
.vop_add_writecount = null_add_writecount,
+ .vop_vput_pair = null_vput_pair,
};
VFS_VOP_VECTOR_REGISTER(null_vnodeops);