ext3-lookup-dotdot-2.6.9.patch

非常经典的一个分布式系统

Index: linux-2.6.9-full/fs/ext3/iopen.c
===================================================================
--- linux-2.6.9-full.orig/fs/ext3/iopen.c	2006-04-25 08:51:11.000000000 +0400
+++ linux-2.6.9-full/fs/ext3/iopen.c	2006-05-06 01:21:11.000000000 +0400
@@ -94,9 +94,12 @@ static struct dentry *iopen_lookup(struc
 		assert(!(alternate->d_flags & DCACHE_DISCONNECTED));
 	}
 
-	if (!list_empty(&inode->i_dentry)) {
-		alternate = list_entry(inode->i_dentry.next,
-				       struct dentry, d_alias);
+	list_for_each(lp, &inode->i_dentry) {
+		alternate = list_entry(lp, struct dentry, d_alias);
+		/* ignore dentries created for ".." to preserve
+		 * proper dcache hierarchy -- bug 10458 */
+		if (alternate->d_flags & DCACHE_NFSFS_RENAMED)
+			continue;
 		dget_locked(alternate);
 		spin_lock(&alternate->d_lock);
 		alternate->d_flags |= DCACHE_REFERENCED;
Index: linux-2.6.9-full/fs/ext3/namei.c
===================================================================
--- linux-2.6.9-full.orig/fs/ext3/namei.c	2006-05-06 01:21:10.000000000 +0400
+++ linux-2.6.9-full/fs/ext3/namei.c	2006-05-06 01:29:30.000000000 +0400
@@ -1003,6 +1003,38 @@ static struct dentry *ext3_lookup(struct
 			return ERR_PTR(-EACCES);
 	}
 
+	/* ".." shouldn't go into dcache to preserve dcache hierarchy
+	 * otherwise we'll get parent being a child of actual child.
+	 * see bug 10458 for details -bzzz */
+	if (inode && (dentry->d_name.name[0] == '.' && (dentry->d_name.len == 1 ||
+		(dentry->d_name.len == 2 && dentry->d_name.name[1] == '.')))) {
+		struct dentry *tmp, *goal = NULL;
+		struct list_head *lp;
+
+		/* first, look for an existing dentry - any one is good */
+		spin_lock(&dcache_lock);
+		list_for_each(lp, &inode->i_dentry) {
+			tmp = list_entry(lp, struct dentry, d_alias);
+			goal = tmp;
+			dget_locked(goal);
+			break;
+		}
+		if (goal == NULL) {
+			/* there is no alias, we need to make current dentry:
+			 *  a) inaccessible for __d_lookup()
+			 *  b) inaccessible for iopen */
+			J_ASSERT(list_empty(&dentry->d_alias));
+			dentry->d_flags |= DCACHE_NFSFS_RENAMED;
+			/* this is d_instantiate() ... */
+			list_add(&dentry->d_alias, &inode->i_dentry);
+			dentry->d_inode = inode;
+		}
+		spin_unlock(&dcache_lock);
+		if (goal)
+			iput(inode);
+		return goal;
+	}
+
 	return iopen_connect_dentry(dentry, inode, 1);
 }