[PATCH 10/21] namei: shift nameidata inside filename_lookup()

From: Al Viro
Date: Wed May 13 2015 - 18:30:14 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

pass root instead; non-NULL => copy to nd.root and
set LOOKUP_ROOT in flags

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 17350c0..abf65b0 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2117,17 +2117,20 @@ static int path_lookupat(int dfd, const struct filename *name, unsigned flags,
}

static int filename_lookup(int dfd, struct filename *name, unsigned flags,
- struct nameidata *nd, struct path *path)
+ struct path *path, struct path *root)
{
int retval;
- struct nameidata *saved_nd = set_nameidata(nd);
-
- retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd, path);
+ struct nameidata nd, *saved_nd = set_nameidata(&nd);
+ if (unlikely(root)) {
+ nd.root = *root;
+ flags |= LOOKUP_ROOT;
+ }
+ retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, &nd, path);
if (unlikely(retval == -ECHILD))
- retval = path_lookupat(dfd, name, flags, nd, path);
+ retval = path_lookupat(dfd, name, flags, &nd, path);
if (unlikely(retval == -ESTALE))
retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL,
- nd, path);
+ &nd, path);

if (likely(!retval))
audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
@@ -2207,11 +2210,10 @@ out:

int kern_path(const char *name, unsigned int flags, struct path *path)
{
- struct nameidata nd;
struct filename *filename = getname_kernel(name);
if (IS_ERR(filename))
return PTR_ERR(filename);
- return filename_lookup(AT_FDCWD, filename, flags, &nd, path);
+ return filename_lookup(AT_FDCWD, filename, flags, path, NULL);
}
EXPORT_SYMBOL(kern_path);

@@ -2227,7 +2229,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
const char *name, unsigned int flags,
struct path *path)
{
- struct nameidata nd;
+ struct path root = {.mnt = mnt, .dentry = dentry};
struct filename *filename = getname_kernel(name);

BUG_ON(flags & LOOKUP_PARENT);
@@ -2235,11 +2237,8 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
if (IS_ERR(filename))
return PTR_ERR(filename);

- nd.root.dentry = dentry;
- nd.root.mnt = mnt;
- /* the first argument of filename_lookup() is ignored with LOOKUP_ROOT */
- return filename_lookup(AT_FDCWD, filename,
- flags | LOOKUP_ROOT, &nd, path);
+ /* the first argument of filename_lookup() is ignored with root */
+ return filename_lookup(AT_FDCWD, filename, flags , path, &root);
}
EXPORT_SYMBOL(vfs_path_lookup);

@@ -2297,14 +2296,13 @@ EXPORT_SYMBOL(lookup_one_len);
int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
struct path *path, int *empty)
{
- struct nameidata nd;
struct filename *tmp = getname_flags(name, flags, empty);
if (IS_ERR(tmp))
return PTR_ERR(tmp);

BUG_ON(flags & LOOKUP_PARENT);

- return filename_lookup(dfd, tmp, flags, &nd, path);
+ return filename_lookup(dfd, tmp, flags, path, NULL);
}

int user_path_at(int dfd, const char __user *name, unsigned flags,
--
2.1.4

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