Re: linux-next: Tree for Jan 20 -- Kernel panic - Unable to mount root fs

Al Viro
2015-01-22T04:12:41Z

On Wed, Jan 21, 2015 at 09:28:51PM -0500, Paul Moore wrote:

> Al, do you mind if I fold your patch below into the existing patches?

No problem, but I'd probably prefer to put this series through vfs.git.
With the following as the first step:

Cut down on do_path_lookup() callers

Use filename_lookup() instead. And don't bother with creating new
struct filename when caller already has one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
diff --git a/fs/namei.c b/fs/namei.c
index bc35b02..73fcf42 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2046,7 +2046,8 @@ struct dentry *kern_path_locked(const char *name, struct path *path)
{
struct nameidata nd;
struct dentry *d;
- int err = do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, &nd);
+ struct filename filename = {.name = name};
+ int err = filename_lookup(AT_FDCWD, &filename, LOOKUP_PARENT, &nd);
if (err)
return ERR_PTR(err);
if (nd.last_type != LAST_NORM) {
@@ -3290,7 +3291,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
return file;
}

-struct dentry *kern_path_create(int dfd, const char *pathname,
+static struct dentry *filename_create(int dfd, struct filename *name,
struct path *path, unsigned int lookup_flags)
{
struct dentry *dentry = ERR_PTR(-EEXIST);
@@ -3305,7 +3306,7 @@ struct dentry *kern_path_create(int dfd, const char *pathname,
*/
lookup_flags &= LOOKUP_REVAL;

- error = do_path_lookup(dfd, pathname, LOOKUP_PARENT|lookup_flags, &nd);
+ error = filename_lookup(dfd, name, LOOKUP_PARENT|lookup_flags, &nd);
if (error)
return ERR_PTR(error);

@@ -3359,6 +3360,13 @@ out:
path_put(&nd.path);
return dentry;
}
+
+struct dentry *kern_path_create(int dfd, const char *pathname,
+ struct path *path, unsigned int lookup_flags)
+{
+ struct filename filename = {.name = pathname};
+ return filename_create(dfd, &filename, path, lookup_flags);
+}
EXPORT_SYMBOL(kern_path_create);

void done_path_create(struct path *path, struct dentry *dentry)
@@ -3377,7 +3385,7 @@ struct dentry *user_path_create(int dfd, const char __user *pathname,
struct dentry *res;
if (IS_ERR(tmp))
return ERR_CAST(tmp);
- res = kern_path_create(dfd, tmp->name, path, lookup_flags);
+ res = filename_create(dfd, tmp, path, lookup_flags);
putname(tmp);
return res;
}