namei: shift nameidata down into filename_parentat()

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

1 files changed, 43 insertions, 41 deletions

diff --git a/fs/namei.c b/fs/namei.c
index a9c593e4f35e..593cf3b01e74 100644
--- 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;
 }