[PATCH] new (local) helper: user_path_parent()

Preparation to untangling intents mess: reduce the number of do_path_lookup()
callers.

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

diff --git a/fs/namei.c b/fs/namei.c
index edb5e97..38ceb6e 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1352,6 +1352,24 @@ int user_path_at(int dfd, const char __user *name, unsigned flags,
        return err;
 }
 
+static int user_path_parent(int dfd, const char __user *path,
+                       struct nameidata *nd, char **name)
+{
+       char *s = getname(path);
+       int error;
+
+       if (IS_ERR(s))
+               return PTR_ERR(s);
+
+       error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd);
+       if (error)
+               putname(s);
+       else
+               *name = s;
+
+       return error;
+}
+
 /*
  * It's inline, so penalty for filesystems that don't use sticky bit is
  * minimal.
@@ -1989,20 +2007,18 @@ static int may_mknod(mode_t mode)
 asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
                                unsigned dev)
 {
-       int error = 0;
-       char * tmp;
-       struct dentry * dentry;
+       int error;
+       char *tmp;
+       struct dentry *dentry;
        struct nameidata nd;
 
        if (S_ISDIR(mode))
                return -EPERM;
-       tmp = getname(filename);
-       if (IS_ERR(tmp))
-               return PTR_ERR(tmp);
 
-       error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);
+       error = user_path_parent(dfd, filename, &nd, &tmp);
        if (error)
-               goto out;
+               return error;
+
        dentry = lookup_create(&nd, 0);
        if (IS_ERR(dentry)) {
                error = PTR_ERR(dentry);
@@ -2034,7 +2050,6 @@ out_dput:
 out_unlock:
        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
        path_put(&nd.path);
-out:
        putname(tmp);
 
        return error;
@@ -2074,14 +2089,10 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
        struct dentry *dentry;
        struct nameidata nd;
 
-       tmp = getname(pathname);
-       error = PTR_ERR(tmp);
-       if (IS_ERR(tmp))
+       error = user_path_parent(dfd, pathname, &nd, &tmp);
+       if (error)
                goto out_err;
 
-       error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);
-       if (error)
-               goto out;
        dentry = lookup_create(&nd, 1);
        error = PTR_ERR(dentry);
        if (IS_ERR(dentry))
@@ -2099,7 +2110,6 @@ out_dput:
 out_unlock:
        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
        path_put(&nd.path);
-out:
        putname(tmp);
 out_err:
        return error;
@@ -2177,13 +2187,9 @@ static long do_rmdir(int dfd, const char __user *pathname)
        struct dentry *dentry;
        struct nameidata nd;
 
-       name = getname(pathname);
-       if(IS_ERR(name))
-               return PTR_ERR(name);
-
-       error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd);
+       error = user_path_parent(dfd, pathname, &nd, &name);
        if (error)
-               goto exit;
+               return error;
 
        switch(nd.last_type) {
                case LAST_DOTDOT:
@@ -2212,7 +2218,6 @@ exit2:
        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 exit1:
        path_put(&nd.path);
-exit:
        putname(name);
        return error;
 }
@@ -2261,19 +2266,16 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
  */
 static long do_unlinkat(int dfd, const char __user *pathname)
 {
-       int error = 0;
-       char * name;
+       int error;
+       char *name;
        struct dentry *dentry;
        struct nameidata nd;
        struct inode *inode = NULL;
 
-       name = getname(pathname);
-       if(IS_ERR(name))
-               return PTR_ERR(name);
-
-       error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd);
+       error = user_path_parent(dfd, pathname, &nd, &name);
        if (error)
-               goto exit;
+               return error;
+
        error = -EISDIR;
        if (nd.last_type != LAST_NORM)
                goto exit1;
@@ -2300,7 +2302,6 @@ static long do_unlinkat(int dfd, const char __user *pathname)
                iput(inode);    /* truncate the inode here */
 exit1:
        path_put(&nd.path);
-exit:
        putname(name);
        return error;
 
@@ -2350,23 +2351,20 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
 asmlinkage long sys_symlinkat(const char __user *oldname,
                              int newdfd, const char __user *newname)
 {
-       int error = 0;
-       char * from;
-       char * to;
+       int error;
+       char *from;
+       char *to;
        struct dentry *dentry;
        struct nameidata nd;
 
        from = getname(oldname);
-       if(IS_ERR(from))
+       if (IS_ERR(from))
                return PTR_ERR(from);
-       to = getname(newname);
-       error = PTR_ERR(to);
-       if (IS_ERR(to))
-               goto out_putname;
 
-       error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
+       error = user_path_parent(newdfd, newname, &nd, &to);
        if (error)
-               goto out;
+               goto out_putname;
+
        dentry = lookup_create(&nd, 0);
        error = PTR_ERR(dentry);
        if (IS_ERR(dentry))
@@ -2382,7 +2380,6 @@ out_dput:
 out_unlock:
        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
        path_put(&nd.path);
-out:
        putname(to);
 out_putname:
        putname(from);
@@ -2449,21 +2446,18 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
        struct nameidata nd;
        struct path old_path;
        int error;
-       char * to;
+       char *to;
 
        if ((flags & ~AT_SYMLINK_FOLLOW) != 0)
                return -EINVAL;
 
-       to = getname(newname);
-       if (IS_ERR(to))
-               return PTR_ERR(to);
-
        error = user_path_at(olddfd, oldname,
                             flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
                             &old_path);
        if (error)
-               goto exit;
-       error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
+               return error;
+
+       error = user_path_parent(newdfd, newname, &nd, &to);
        if (error)
                goto out;
        error = -EXDEV;
@@ -2484,10 +2478,9 @@ out_unlock:
        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 out_release:
        path_put(&nd.path);
+       putname(to);
 out:
        path_put(&old_path);
-exit:
-       putname(to);
 
        return error;
 }
@@ -2643,20 +2636,22 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
        return error;
 }
 
-static int do_rename(int olddfd, const char *oldname,
-                       int newdfd, const char *newname)
+asmlinkage long sys_renameat(int olddfd, const char __user *oldname,
+                            int newdfd, const char __user *newname)
 {
-       int error = 0;
-       struct dentry * old_dir, * new_dir;
-       struct dentry * old_dentry, *new_dentry;
-       struct dentry * trap;
+       struct dentry *old_dir, *new_dir;
+       struct dentry *old_dentry, *new_dentry;
+       struct dentry *trap;
        struct nameidata oldnd, newnd;
+       char *from;
+       char *to;
+       int error;
 
-       error = do_path_lookup(olddfd, oldname, LOOKUP_PARENT, &oldnd);
+       error = user_path_parent(olddfd, oldname, &oldnd, &from);
        if (error)
                goto exit;
 
-       error = do_path_lookup(newdfd, newname, LOOKUP_PARENT, &newnd);
+       error = user_path_parent(newdfd, newname, &newnd, &to);
        if (error)
                goto exit1;
 
@@ -2718,29 +2713,11 @@ exit3:
        unlock_rename(new_dir, old_dir);
 exit2:
        path_put(&newnd.path);
+       putname(to);
 exit1:
        path_put(&oldnd.path);
-exit:
-       return error;
-}
-
-asmlinkage long sys_renameat(int olddfd, const char __user *oldname,
-                            int newdfd, const char __user *newname)
-{
-       int error;
-       char * from;
-       char * to;
-
-       from = getname(oldname);
-       if(IS_ERR(from))
-               return PTR_ERR(from);
-       to = getname(newname);
-       error = PTR_ERR(to);
-       if (!IS_ERR(to)) {
-               error = do_rename(olddfd, from, newdfd, to);
-               putname(to);
-       }
        putname(from);
+exit:
        return error;
 }