[src/trunk]: src/sys/fs Onionfs needs to know about parsepath too, in case it...

[dholland <dholland%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bed22c218d38
branches:  trunk
changeset: 379988:bed22c218d38
user:      dholland <dholland%NetBSD.org@localhost>
date:      Tue Jun 29 22:38:46 2021 +0000

description:
Onionfs needs to know about parsepath too, in case it has one of the
other cases underneath it.

The solution here is not really very good (take the longer
path-to-consume if they're different) but it will serve for the cases
that exist.

(If we were to add a fs that really uses different naming semantics,
we'd have to take additional steps; probably it doesn't make sense to
allow unionfs to union such a thing with a normal fs and attempting it
should fail at mount time.)

Update fs/unionfs as well to avoid increasing the current set of
compile failures there. Though maybe it's time to just remove
fs/unionfs.

diffstat:

 sys/fs/union/union_vnops.c     |  41 ++++++++++++++++++++++++++++++++++++++---
 sys/fs/unionfs/unionfs_vnops.c |  38 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 75 insertions(+), 4 deletions(-)

diffs (131 lines):

diff -r ad3cb699d80a -r bed22c218d38 sys/fs/union/union_vnops.c
--- a/sys/fs/union/union_vnops.c        Tue Jun 29 22:38:10 2021 +0000
+++ b/sys/fs/union/union_vnops.c        Tue Jun 29 22:38:46 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: union_vnops.c,v 1.75 2021/06/29 22:34:07 dholland Exp $        */
+/*     $NetBSD: union_vnops.c,v 1.76 2021/06/29 22:38:46 dholland Exp $        */
 
 /*
  * Copyright (c) 1992, 1993, 1994, 1995
@@ -72,7 +72,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.75 2021/06/29 22:34:07 dholland Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.76 2021/06/29 22:38:46 dholland Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -93,6 +93,7 @@
 #include <miscfs/genfs/genfs.h>
 #include <miscfs/specfs/specdev.h>
 
+int union_parsepath(void *);
 int union_lookup(void *);
 int union_create(void *);
 int union_whiteout(void *);
@@ -144,7 +145,7 @@ static int union_lookup1(struct vnode *,
 int (**union_vnodeop_p)(void *);
 const struct vnodeopv_entry_desc union_vnodeop_entries[] = {
        { &vop_default_desc, vn_default_error },
-       { &vop_parsepath_desc, genfs_parsepath },       /* parsepath */
+       { &vop_parsepath_desc, union_parsepath },       /* parsepath */
        { &vop_lookup_desc, union_lookup },             /* lookup */
        { &vop_create_desc, union_create },             /* create */
        { &vop_whiteout_desc, union_whiteout },         /* whiteout */
@@ -197,6 +198,40 @@ const struct vnodeopv_desc union_vnodeop
        ((vp)->v_type == VBLK || (vp)->v_type == VCHR || \
        (vp)->v_type == VSOCK || (vp)->v_type == VFIFO)
 
+int
+union_parsepath(void *v)
+{
+       struct vop_parsepath_args /* {
+               struct vnode *a_dvp;
+               const char *a_name;
+               size_t *a_retval;
+       } */ *ap = v;
+       struct vnode *upperdvp, *lowerdvp;
+       size_t upper, lower;
+       int error;
+
+       upperdvp = UPPERVP(ap->a_dvp);
+       lowerdvp = LOWERVP(ap->a_dvp);
+
+       error = VOP_PARSEPATH(upperdvp, ap->a_name, &upper);
+       if (error) {
+               return error;
+       }
+
+       error = VOP_PARSEPATH(lowerdvp, ap->a_name, &lower);
+       if (error) {
+               return error;
+       }
+
+       /*
+        * If they're different, use the larger one. This is not a
+        * comprehensive solution, but it's sufficient for the
+        * non-default cases of parsepath that currently exist.
+        */
+       *ap->a_retval = MAX(upper, lower);
+       return 0;
+}
+
 static int
 union_lookup1(struct vnode *udvp, struct vnode **dvpp, struct vnode **vpp,
        struct componentname *cnp)
diff -r ad3cb699d80a -r bed22c218d38 sys/fs/unionfs/unionfs_vnops.c
--- a/sys/fs/unionfs/unionfs_vnops.c    Tue Jun 29 22:38:10 2021 +0000
+++ b/sys/fs/unionfs/unionfs_vnops.c    Tue Jun 29 22:38:46 2021 +0000
@@ -65,6 +65,42 @@
 #endif
 
 static int
+unionfs_parsepath(void *v)
+{
+       struct vop_parsepath_args /* {
+               struct vnode *a_dvp;
+               const char *a_name;
+               size_t *a_retval;
+       } */ *ap = v;
+       struct unionfs_node *dunp;
+       struct vnode *upperdvp, *lowerdvp;
+       size_t upper, lower;
+       int error;
+
+       dunp = VTOUNIONFS(ap->a_dvp);
+       upperdvp = dunp->un_uppervp;
+       lowerdvp = dunp->un_lowervp;
+
+       error = VOP_PARSEPATH(upperdvp, ap->a_name, &upper);
+       if (error) {
+               return error;
+       }
+
+       error = VOP_PARSEPATH(lowerdvp, ap->a_name, &lower);
+       if (error) {
+               return error;
+       }
+
+       /*
+        * If they're different, use the larger one. This is not a
+        * comprehensive solution, but it's sufficient for the
+        * non-default cases of parsepath that currently exist.
+        */
+       *ap->a_retval = MAX(upper, lower);
+       return 0;
+}
+
+static int
 unionfs_lookup(void *v)
 {
        struct vop_lookup_args *ap = v;
@@ -1814,7 +1850,7 @@ unionfs_revoke(void *v)
 int (**unionfs_vnodeop_p)(void *);
 const struct vnodeopv_entry_desc unionfs_vnodeop_entries[] = {
        { &vop_default_desc, vn_default_error },
-       { &vop_parsepath_desc, genfs_parsepath },       /* parsepath */
+       { &vop_parsepath_desc, unionfs_parsepath },     /* parsepath */
        { &vop_lookup_desc, unionfs_lookup },           /* lookup */
        { &vop_create_desc, unionfs_create },           /* create */
        { &vop_whiteout_desc, unionfs_whiteout },       /* whiteout */