[RFC][PATCH v3 39/55] path_connected(): pass mount and dentry separately

Al Viro
2020-03-01T21:54:05Z

eventually we'll want to do that check *before* mangling
nd->path.dentry...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index b73ff6dcca24..971d0ee11286 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -550,22 +550,20 @@ static int __nd_alloc_stack(struct nameidata *nd)
}

/**
- * path_connected - Verify that a path->dentry is below path->mnt.mnt_root
- * @path: nameidate to verify
+ * path_connected - Verify that a dentry is below mnt.mnt_root
*
* Rename can sometimes move a file or directory outside of a bind
* mount, path_connected allows those cases to be detected.
*/
-static bool path_connected(const struct path *path)
+static bool path_connected(struct vfsmount *mnt, struct dentry *dentry)
{
- struct vfsmount *mnt = path->mnt;
struct super_block *sb = mnt->mnt_sb;

/* Bind mounts and multi-root filesystems can have disconnected paths */
if (!(sb->s_iflags & SB_I_MULTIROOT) && (mnt->mnt_root == sb->s_root))
return true;

- return is_subdir(path->dentry, mnt->mnt_root);
+ return is_subdir(dentry, mnt->mnt_root);
}

static inline int nd_alloc_stack(struct nameidata *nd)
@@ -1386,7 +1384,7 @@ static int follow_dotdot_rcu(struct nameidata *nd)
return -ECHILD;
nd->path.dentry = parent;
nd->seq = seq;
- if (unlikely(!path_connected(&nd->path)))
+ if (unlikely(!path_connected(nd->path.mnt, parent)))
return -ECHILD;
break;
} else {
@@ -1448,7 +1446,7 @@ static int path_parent_directory(struct path *path)
/* rare case of legitimate dget_parent()... */
path->dentry = dget_parent(path->dentry);
dput(old);
- if (unlikely(!path_connected(path)))
+ if (unlikely(!path_connected(path->mnt, path->dentry)))
return -ENOENT;
return 0;
}
--
2.11.0