namei: shift nameidata down into filename_parentat()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index a9c593e4f35e9d956eb05a3cbd5cb05f7ca4c051..593cf3b01e74c17c117da6938b760eac9f9b9d25 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2146,7 +2146,8 @@ static int filename_lookup(int dfd, struct filename *name, unsigned flags,
 
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
 static int path_parentat(int dfd, const struct filename *name,
-                               unsigned int flags, struct nameidata *nd)
+                               unsigned int flags, struct nameidata *nd,
+                               struct path *parent)
 {
        const char *s = path_init(dfd, name, flags, nd);
        int err;
@@ -2155,26 +2156,34 @@ static int path_parentat(int dfd, const struct filename *name,
        err = link_path_walk(s, nd);
        if (!err)
                err = complete_walk(nd);
-       if (err)
-               terminate_walk(nd);
+       if (!err) {
+               *parent = nd->path;
+               nd->path.mnt = NULL;
+               nd->path.dentry = NULL;
+       }
+       terminate_walk(nd);
        path_cleanup(nd);
        return err;
 }
 
 static int filename_parentat(int dfd, struct filename *name,
-                               unsigned int flags, struct nameidata *nd)
+                               unsigned int flags, struct path *parent,
+                               struct qstr *last, int *type)
 {
        int retval;
-       struct nameidata *saved_nd = set_nameidata(nd);
+       struct nameidata nd, *saved_nd = set_nameidata(&nd);
 
-       retval = path_parentat(dfd, name, flags | LOOKUP_RCU, nd);
+       retval = path_parentat(dfd, name, flags | LOOKUP_RCU, &nd, parent);
        if (unlikely(retval == -ECHILD))
-               retval = path_parentat(dfd, name, flags, nd);
+               retval = path_parentat(dfd, name, flags, &nd, parent);
        if (unlikely(retval == -ESTALE))
-               retval = path_parentat(dfd, name, flags | LOOKUP_REVAL, nd);
-
-       if (likely(!retval))
-               audit_inode(name, nd->path.dentry, LOOKUP_PARENT);
+               retval = path_parentat(dfd, name, flags | LOOKUP_REVAL,
+                                       &nd, parent);
+       if (likely(!retval)) {
+               *last = nd.last;
+               *type = nd.last_type;
+               audit_inode(name, parent->dentry, LOOKUP_PARENT);
+       }
        restore_nameidata(saved_nd);
        return retval;
 }
@@ -2183,31 +2192,30 @@ static int filename_parentat(int dfd, struct filename *name,
 struct dentry *kern_path_locked(const char *name, struct path *path)
 {
        struct filename *filename = getname_kernel(name);
-       struct nameidata nd;
+       struct qstr last;
+       int type;
        struct dentry *d;
        int err;
 
        if (IS_ERR(filename))
                return ERR_CAST(filename);
 
-       err = filename_parentat(AT_FDCWD, filename, 0, &nd);
+       err = filename_parentat(AT_FDCWD, filename, 0, path, &last, &type);
        if (err) {
                d = ERR_PTR(err);
                goto out;
        }
-       if (nd.last_type != LAST_NORM) {
-               path_put(&nd.path);
+       if (type != LAST_NORM) {
+               path_put(path);
                d = ERR_PTR(-EINVAL);
                goto out;
        }
-       mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
-       d = __lookup_hash(&nd.last, nd.path.dentry, 0);
+       mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+       d = __lookup_hash(&last, path->dentry, 0);
        if (IS_ERR(d)) {
-               mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
-               path_put(&nd.path);
-               goto out;
+               mutex_unlock(&path->dentry->d_inode->i_mutex);
+               path_put(path);
        }
-       *path = nd.path;
 out:
        putname(filename);
        return d;
@@ -2317,7 +2325,6 @@ user_path_parent(int dfd, const char __user *path,
                 int *type,
                 unsigned int flags)
 {
-       struct nameidata nd;
        struct filename *s = getname(path);
        int error;
 
@@ -2327,15 +2334,11 @@ user_path_parent(int dfd, const char __user *path,
        if (IS_ERR(s))
                return s;
 
-       error = filename_parentat(dfd, s, flags, &nd);
+       error = filename_parentat(dfd, s, flags, parent, last, type);
        if (error) {
                putname(s);
-               return ERR_PTR(error);
+               s = ERR_PTR(error);
        }
-       *parent = nd.path;
-       *last = nd.last;
-       *type = nd.last_type;
-
        return s;
 }
 
@@ -3394,7 +3397,8 @@ static struct dentry *filename_create(int dfd, struct filename *name,
                                struct path *path, unsigned int lookup_flags)
 {
        struct dentry *dentry = ERR_PTR(-EEXIST);
-       struct nameidata nd;
+       struct qstr last;
+       int type;
        int err2;
        int error;
        bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
@@ -3405,7 +3409,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
         */
        lookup_flags &= LOOKUP_REVAL;
 
-       error = filename_parentat(dfd, name, lookup_flags, &nd);
+       error = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
        if (error)
                return ERR_PTR(error);
 
@@ -3413,18 +3417,17 @@ static struct dentry *filename_create(int dfd, struct filename *name,
         * Yucky last component or no last component at all?
         * (foo/., foo/.., /////)
         */
-       if (nd.last_type != LAST_NORM)
+       if (type != LAST_NORM)
                goto out;
-       nd.flags &= ~LOOKUP_PARENT;
-       nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL;
 
        /* don't fail immediately if it's r/o, at least try to report other errors */
-       err2 = mnt_want_write(nd.path.mnt);
+       err2 = mnt_want_write(path->mnt);
        /*
         * Do the final lookup.
         */
-       mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
-       dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags);
+       lookup_flags |= LOOKUP_CREATE | LOOKUP_EXCL;
+       mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+       dentry = __lookup_hash(&last, path->dentry, lookup_flags);
        if (IS_ERR(dentry))
                goto unlock;
 
@@ -3438,7 +3441,7 @@ static struct dentry *filename_create(int dfd, struct filename *name,
         * all is fine. Let's be bastards - you had / on the end, you've
         * been asking for (non-existent) directory. -ENOENT for you.
         */
-       if (unlikely(!is_dir && nd.last.name[nd.last.len])) {
+       if (unlikely(!is_dir && last.name[last.len])) {
                error = -ENOENT;
                goto fail;
        }
@@ -3446,17 +3449,16 @@ static struct dentry *filename_create(int dfd, struct filename *name,
                error = err2;
                goto fail;
        }
-       *path = nd.path;
        return dentry;
 fail:
        dput(dentry);
        dentry = ERR_PTR(error);
 unlock:
-       mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+       mutex_unlock(&path->dentry->d_inode->i_mutex);
        if (!err2)
-               mnt_drop_write(nd.path.mnt);
+               mnt_drop_write(path->mnt);
 out:
-       path_put(&nd.path);
+       path_put(path);
        return dentry;
 }