git: 9a0bee9f6a77 - main - Make vn_fullpath_hardlink() externally callable

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=9a0bee9f6a77a85e4dfb27c9a33d4e210d05b469

commit 9a0bee9f6a77a85e4dfb27c9a33d4e210d05b469
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2021-10-23 00:23:17 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2021-10-28 17:49:26 +0000

    Make vn_fullpath_hardlink() externally callable
    
    Reviewed by:    markj
    Tested by:      pho
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D32611
---
 sys/kern/vfs_cache.c | 28 +++++++++++++---------------
 sys/sys/vnode.h      |  3 +++
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index 99f7314822f0..006f16587021 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -579,8 +579,6 @@ DEBUGNODE_ULONG(vnodes_cel_3_failures, cache_lock_vnodes_cel_3_failures,
     "Number of times 3-way vnode locking failed");
 
 static void cache_zap_locked(struct namecache *ncp);
-static int vn_fullpath_hardlink(struct nameidata *ndp, char **retbuf,
-    char **freebuf, size_t *buflen);
 static int vn_fullpath_any_smr(struct vnode *vp, struct vnode *rdir, char *buf,
     char **retbuf, size_t *buflen, size_t addend);
 static int vn_fullpath_any(struct vnode *vp, struct vnode *rdir, char *buf,
@@ -3132,7 +3130,8 @@ kern___realpathat(struct thread *td, int fd, const char *path, char *buf,
 	    pathseg, path, fd, &cap_fstat_rights, td);
 	if ((error = namei(&nd)) != 0)
 		return (error);
-	error = vn_fullpath_hardlink(&nd, &retbuf, &freebuf, &size);
+	error = vn_fullpath_hardlink(nd.ni_vp, nd.ni_dvp, nd.ni_cnd.cn_nameptr,
+	    nd.ni_cnd.cn_namelen, &retbuf, &freebuf, &size);
 	if (error == 0) {
 		error = copyout(retbuf, buf, size);
 		free(freebuf, M_TEMP);
@@ -3593,8 +3592,9 @@ vn_fullpath_any(struct vnode *vp, struct vnode *rdir, char *buf, char **retbuf,
 /*
  * Resolve an arbitrary vnode to a pathname (taking care of hardlinks).
  *
- * Since the namecache does not track hardlinks, the caller is expected to first
- * look up the target vnode with SAVENAME | WANTPARENT flags passed to namei.
+ * Since the namecache does not track hardlinks, the caller is
+ * expected to first look up the target vnode with SAVENAME |
+ * WANTPARENT flags passed to namei to get dvp and vp.
  *
  * Then we have 2 cases:
  * - if the found vnode is a directory, the path can be constructed just by
@@ -3602,14 +3602,13 @@ vn_fullpath_any(struct vnode *vp, struct vnode *rdir, char *buf, char **retbuf,
  * - otherwise we populate the buffer with the saved name and start resolving
  *   from the parent
  */
-static int
-vn_fullpath_hardlink(struct nameidata *ndp, char **retbuf, char **freebuf,
-    size_t *buflen)
+int
+vn_fullpath_hardlink(struct vnode *vp, struct vnode *dvp,
+    const char *hrdl_name, size_t hrdl_name_length,
+    char **retbuf, char **freebuf, size_t *buflen)
 {
 	char *buf, *tmpbuf;
 	struct pwd *pwd;
-	struct componentname *cnp;
-	struct vnode *vp;
 	size_t addend;
 	int error;
 	enum vtype type;
@@ -3622,7 +3621,7 @@ vn_fullpath_hardlink(struct nameidata *ndp, char **retbuf, char **freebuf,
 	buf = malloc(*buflen, M_TEMP, M_WAITOK);
 
 	addend = 0;
-	vp = ndp->ni_vp;
+
 	/*
 	 * Check for VBAD to work around the vp_crossmp bug in lookup().
 	 *
@@ -3648,8 +3647,7 @@ vn_fullpath_hardlink(struct nameidata *ndp, char **retbuf, char **freebuf,
 		goto out_bad;
 	}
 	if (type != VDIR) {
-		cnp = &ndp->ni_cnd;
-		addend = cnp->cn_namelen + 2;
+		addend = hrdl_name_length + 2;
 		if (*buflen < addend) {
 			error = ENOMEM;
 			goto out_bad;
@@ -3657,9 +3655,9 @@ vn_fullpath_hardlink(struct nameidata *ndp, char **retbuf, char **freebuf,
 		*buflen -= addend;
 		tmpbuf = buf + *buflen;
 		tmpbuf[0] = '/';
-		memcpy(&tmpbuf[1], cnp->cn_nameptr, cnp->cn_namelen);
+		memcpy(&tmpbuf[1], hrdl_name, hrdl_name_length);
 		tmpbuf[addend - 1] = '\0';
-		vp = ndp->ni_dvp;
+		vp = dvp;
 	}
 
 	vfs_smr_enter();
diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
index a9b57dd4c25d..18bba17011e8 100644
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -697,6 +697,9 @@ int	vn_vptocnp(struct vnode **vp, char *buf, size_t *buflen);
 int	vn_getcwd(char *buf, char **retbuf, size_t *buflen);
 int	vn_fullpath(struct vnode *vp, char **retbuf, char **freebuf);
 int	vn_fullpath_global(struct vnode *vp, char **retbuf, char **freebuf);
+int	vn_fullpath_hardlink(struct vnode *vp, struct vnode *dvp,
+	    const char *hdrl_name, size_t hrdl_name_length, char **retbuf,
+	    char **freebuf, size_t *buflen);
 struct vnode *
 	vn_dir_dd_ino(struct vnode *vp);
 int	vn_commname(struct vnode *vn, char *buf, u_int buflen);