From 98dc568bc2ebefe4c0cb315a7fb7eff8bbb43176 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 10 Aug 2010 11:41:38 +0200 Subject: [PATCH] vfs: __d_path: dont prepend the name of the root dentry In the old times pseudo-filesystems set the name of theroot dentry to some prefix like "pipe:" and the name of the child dentry to "[123]" and relied on a hack in __d_path() to replace the preceding slash with the root's name to get "pipe:[123]". Then the d_dname() dentry operation was introduced which solved the same problem without having to pre-fill the name in each dentry. Currently the following pseudo filesystems exist in the kernel: perfmon mtd anon_inode bdev pipe socket Of these only perfmon, anon_inode, pipe and socket create sub-dentries, all of which have now been switched to using d_dname(). bdev and mtd only create inodes. This means that now the hack to overwrite the slash can be removed, so for unreachable paths (e.g. within a detached mount) the path string won't be polluted with garbage. For these cases a subsequent patch will add a prefix, indicating that the path is unreachable. Signed-off-by: Miklos Szeredi Signed-off-by: Al Viro --- fs/dcache.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 995d08069d26..f1809e6b9fda 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1970,9 +1970,15 @@ char *__d_path(const struct path *path, struct path *root, return retval; global_root: - retval += 1; /* hit the slash */ - if (prepend_name(&retval, &buflen, &dentry->d_name) != 0) - goto Elong; + /* + * Filesystems needing to implement special "root names" + * should do so with ->d_dname() + */ + if (IS_ROOT(dentry) && + (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) { + WARN(1, "Root dentry has weird name <%.*s>\n", + (int) dentry->d_name.len, dentry->d_name.name); + } root->mnt = vfsmnt; root->dentry = dentry; goto out; -- GitLab