PERFORCE change 178714 for review

[Efstratios Karatzas]

http://p4web.freebsd.org/@@178714?ac=10

Change 178714 by gpf at gpf_desktop on 2010/05/24 14:06:34

	* the second parameter from VOP_VPTOCNP() should be vdrop()ed after
	the call - done
	* dont really need exclusive locks; now I use shared locks
	* dir_ilookup() still only works for UFS, added a check so that the
	function will return if the fs is not ufs 

Affected files ...

.. //depot/projects/soc2010/gpf_audit/vn_fullpath_nocache.c#3 edit

Differences ...

==== //depot/projects/soc2010/gpf_audit/vn_fullpath_nocache.c#3 (text+ko) ====

@@ -75,11 +75,18 @@
 	KASSERT("dvp != NULL", "dir_ilookup: dvp == NULL");
 	KASSERT("name != NULL", "dir_ilookup: name == NULL");
 
+	/* XXXgpf: temporary, must be a better way to check this than f_type or f_fstypename */
+	if (strcmp(vp->v_mount->mnt_stat.f_fstypename, "ufs")) {
+		uprintf("only ufs supported\n");
+		return 1;
+	}
+
 	foundit = 0;
 	dirbuflen = ((struct inode *)dvp->v_data)->i_size;
 	dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
 	td = curthread;
 	
+	/* prep the call to VOP_READDIR() */
 	iov.iov_base = dirbuf;
 	iov.iov_len = dirbuflen;
 	io.uio_iov = &iov;
@@ -90,7 +97,7 @@
 	io.uio_rw = UIO_READ;
 	io.uio_td = td;
 	eofflag = 0;
-	
+
 	error = VOP_READDIR(dvp, &io, td->td_ucred, &eofflag, NULL, NULL);
 	if (error) {
 		uprintf("VOP_READDIR failure %d\n", error);
@@ -146,9 +153,9 @@
  * Retrieve the full filesystem path that corresponds to a vnode without use of the 
  * name cache.
  * - A directory hint (UFS file_id of the directory that contains the vnode) may be 
- *   supplied to facilitate the search is our target is not a directory itself.
+ *   supplied to facilitate the search if our target is not a directory itself.
  * - flags should be set to PARENT_HINT, if the directory hint is supplied
- *   and to EXHAUSTIVE_SEARCH, if we are willing to go intro great trouble to get this path
+ *   and to EXHAUSTIVE_SEARCH, if we are willing to go intro great trouble to get this path.
  * 
  * Author's note: This only works for UFS filesystems (for now).
  * Oh, also EXHAUSTIVE_SEARCH will kernel panic :-D
@@ -187,12 +194,11 @@
 	 * - If our target is a directory, move on to the part where we traverse the '..' entries.
 	 * - If not, either use the directory_hint if it's available or do an exhaustive search on the fs (xD) so
 	 *   that we can connect the vp with 'a' parent directory.
-	 */	
+	 */
 	if (vp->v_type != VDIR) {
 		/* grab the parent directory using the directory_hint */
 		if ((flags & PARENT_HINT) && vp->v_type != VDIR) {
-			/* XXXgpf: should change the locktypes from excl to smth else */
-			error = VFS_VGET(vp->v_mount, directory_hint, LK_EXCLUSIVE, &dvp);
+			error = VFS_VGET(vp->v_mount, directory_hint, LK_SHARED, &dvp);
 			/* in case of failure, proceed to exhaustive search */
 			if (error) {
 				uprintf("VFS_VGET failure %d\n", error);
@@ -215,7 +221,7 @@
 		if ((flags & EXHAUSTIVE_SEARCH) && dvp == NULL) {
 			/*
 			 * XXXgpf: this actually does not work because when the thread will try to sleep,
-			 * e.g. in VOP_READDIR the kernel will panic because we have ilocked mp >.<
+			 * e.g. in VOP_READDIR, the kernel will panic because we have ilocked mp >.<
 			 */
 			MNT_ILOCK(mp);
 			if (!TAILQ_EMPTY(&mp->mnt_nvnodelist)) {
@@ -223,7 +229,7 @@
 
 				TAILQ_FOREACH(tvp, &mp->mnt_nvnodelist, v_nmntvnodes) {
 					if (tvp->v_type == VDIR) {
-						vn_lock(tvp, LK_EXCLUSIVE);
+						vn_lock(tvp, LK_SHARED);
 						/* grab the name that is being used to reference vp */
 						error = dir_ilookup(vp, tvp, fname, &fnamelen);
 						
@@ -267,7 +273,7 @@
 	else {
 		dvp = vp;
 		vref(dvp);
-		vn_lock(dvp, LK_EXCLUSIVE);
+		vn_lock(dvp, LK_SHARED);
 	}
 	
 	/*
@@ -318,9 +324,10 @@
 		buf[--buflen] = '/';		
 		if (dvp != NULL) 
 			vput(dvp);
-
+		
+		vdrop(upper_dvp);
 		dvp = upper_dvp;
-		vn_lock(dvp, LK_EXCLUSIVE);
+		vn_lock(dvp, LK_SHARED);
 		vref(dvp);
 	} /* while */