[RFC][PATCH v4 48/69] follow_dotdot{,_rcu}(): switch to use of step_into()

Al Viro
2020-03-13T23:56:02Z

gets the regular mount crossing on result of ..

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 31 +++++++------------------------
1 file changed, 7 insertions(+), 24 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 1749e435edc7..9c775013368a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1722,33 +1722,18 @@ static const char *follow_dotdot_rcu(struct nameidata *nd)
/* we know that mountpoint was pinned */
nd->path.dentry = mountpoint;
nd->path.mnt = &mparent->mnt;
- inode = inode2;
+ inode = nd->inode = inode2;
nd->seq = seq;
}
}
if (unlikely(!parent)) {
if (unlikely(nd->flags & LOOKUP_BENEATH))
return ERR_PTR(-ECHILD);
+ return step_into(nd, WALK_NOFOLLOW,
+ nd->path.dentry, nd->inode, nd->seq);
} else {
- nd->path.dentry = parent;
- nd->seq = seq;
+ return step_into(nd, WALK_NOFOLLOW, parent, inode, seq);
}
- while (unlikely(d_mountpoint(nd->path.dentry))) {
- struct mount *mounted;
- mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry);
- if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))
- return ERR_PTR(-ECHILD);
- if (!mounted)
- break;
- if (unlikely(nd->flags & LOOKUP_NO_XDEV))
- return ERR_PTR(-ECHILD);
- nd->path.mnt = &mounted->mnt;
- nd->path.dentry = mounted->mnt.mnt_root;
- inode = nd->path.dentry->d_inode;
- nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
- }
- nd->inode = inode;
- return NULL;
}

static const char *follow_dotdot(struct nameidata *nd)
@@ -1774,13 +1759,11 @@ static const char *follow_dotdot(struct nameidata *nd)
if (unlikely(!parent)) {
if (unlikely(nd->flags & LOOKUP_BENEATH))
return ERR_PTR(-EXDEV);
+ return step_into(nd, WALK_NOFOLLOW,
+ dget(nd->path.dentry), nd->inode, nd->seq);
} else {
- dput(nd->path.dentry);
- nd->path.dentry = parent;
+ return step_into(nd, WALK_NOFOLLOW, parent, parent->d_inode, 0);
}
- follow_mount(&nd->path);
- nd->inode = nd->path.dentry->d_inode;
- return NULL;
}

static const char *handle_dots(struct nameidata *nd, int type)
--
2.11.0