[PATCH] reiserfs: eliminate private use of struct file in xattr

After several posts and bug reports regarding interaction with the NULL
nameidata, here's a patch to clean up the mess with struct file in the
reiserfs xattr code.

As observed in several of the posts, there's really no need for struct file
to exist in the xattr code. It was really only passed around due to the
f_op->readdir() and a_ops->{prepare,commit}_write prototypes requiring it.

reiserfs_prepare_write() and reiserfs_commit_write() don't actually use the
struct file passed to it, and the xattr code uses a private version of
reiserfs_readdir() to enumerate the xattr directories.

Signed-off-by: Jeff Mahoney <[e-mail]>
Acked-by: Al Viro <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Dave Hansen <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

fs/reiserfs/xattr.c

···
 	dput(xadir);
 	if (err)
 		xafile = ERR_PTR(err);
-	return xafile;
-}
-
-/* Opens a file pointer to the attribute associated with inode */
-static struct file *open_xa_file(const struct inode *inode, const char *name,
-				 int flags)
-{
-	struct dentry *xafile;
-	struct file *fp;
-
-	xafile = get_xa_file_dentry(inode, name, flags);
-	if (IS_ERR(xafile))
-		return ERR_PTR(PTR_ERR(xafile));
 	else if (!xafile->d_inode) {
 		dput(xafile);
-		return ERR_PTR(-ENODATA);
+		xafile = ERR_PTR(-ENODATA);
 	}
-
-	fp = dentry_open(xafile, NULL, O_RDWR);
-	/* dentry_open dputs the dentry if it fails */
-
-	return fp;
+	return xafile;
 }
 
 /*
···
  * we're called with i_mutex held, so there are no worries about the directory
  * changing underneath us.
  */
-static int __xattr_readdir(struct file *filp, void *dirent, filldir_t filldir)
+static int __xattr_readdir(struct inode *inode, void *dirent, filldir_t filldir)
 {
-	struct inode *inode = filp->f_path.dentry->d_inode;
 	struct cpu_key pos_key;	/* key of current position in the directory (key of directory entry) */
 	INITIALIZE_PATH(path_to_entry);
 	struct buffer_head *bh;
···
  *
  */
 static
-int xattr_readdir(struct file *file, filldir_t filler, void *buf)
+int xattr_readdir(struct inode *inode, filldir_t filler, void *buf)
 {
-	struct inode *inode = file->f_path.dentry->d_inode;
-	int res = -ENOTDIR;
-	if (!file->f_op || !file->f_op->readdir)
-		goto out;
+	int res = -ENOENT;
 	mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR);
-//        down(&inode->i_zombie);
-	res = -ENOENT;
 	if (!IS_DEADDIR(inode)) {
 		lock_kernel();
-		res = __xattr_readdir(file, buf, filler);
+		res = __xattr_readdir(inode, buf, filler);
 		unlock_kernel();
 	}
-//        up(&inode->i_zombie);
 	mutex_unlock(&inode->i_mutex);
-      out:
 	return res;
 }
 
···
 		   size_t buffer_size, int flags)
 {
 	int err = 0;
-	struct file *fp;
+	struct dentry *dentry;
 	struct page *page;
 	char *data;
 	struct address_space *mapping;
···
 		xahash = xattr_hash(buffer, buffer_size);
 
       open_file:
-	fp = open_xa_file(inode, name, flags);
-	if (IS_ERR(fp)) {
-		err = PTR_ERR(fp);
+	dentry = get_xa_file_dentry(inode, name, flags);
+	if (IS_ERR(dentry)) {
+		err = PTR_ERR(dentry);
 		goto out;
 	}
 
-	xinode = fp->f_path.dentry->d_inode;
+	xinode = dentry->d_inode;
 	REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 
 	/* we need to copy it off.. */
 	if (xinode->i_nlink > 1) {
-		fput(fp);
+		dput(dentry);
 		err = reiserfs_xattr_del(inode, name);
 		if (err < 0)
 			goto out;
···
 	newattrs.ia_size = buffer_size;
 	newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
 	mutex_lock_nested(&xinode->i_mutex, I_MUTEX_XATTR);
-	err = notify_change(fp->f_path.dentry, &newattrs);
+	err = notify_change(dentry, &newattrs);
 	if (err)
 		goto out_filp;
 
···
 			rxh->h_hash = cpu_to_le32(xahash);
 		}
 
-		err = reiserfs_prepare_write(fp, page, page_offset,
+		err = reiserfs_prepare_write(NULL, page, page_offset,
 					    page_offset + chunk + skip);
 		if (!err) {
 			if (buffer)
 				memcpy(data + skip, buffer + buffer_pos, chunk);
-			err =
-			    reiserfs_commit_write(fp, page, page_offset,
-						  page_offset + chunk +
-						  skip);
+			err = reiserfs_commit_write(NULL, page, page_offset,
+						    page_offset + chunk +
+						    skip);
 		}
 		unlock_page(page);
 		reiserfs_put_page(page);
···
 
       out_filp:
 	mutex_unlock(&xinode->i_mutex);
-	fput(fp);
+	dput(dentry);
 
       out:
 	return err;
···
 		   size_t buffer_size)
 {
 	ssize_t err = 0;
-	struct file *fp;
+	struct dentry *dentry;
 	size_t isize;
 	size_t file_pos = 0;
 	size_t buffer_pos = 0;
···
 	if (get_inode_sd_version(inode) == STAT_DATA_V1)
 		return -EOPNOTSUPP;
 
-	fp = open_xa_file(inode, name, FL_READONLY);
-	if (IS_ERR(fp)) {
-		err = PTR_ERR(fp);
+	dentry = get_xa_file_dentry(inode, name, FL_READONLY);
+	if (IS_ERR(dentry)) {
+		err = PTR_ERR(dentry);
 		goto out;
 	}
 
-	xinode = fp->f_path.dentry->d_inode;
+	xinode = dentry->d_inode;
 	isize = xinode->i_size;
 	REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 
···
 	}
 
       out_dput:
-	fput(fp);
+	dput(dentry);
 
       out:
 	return err;
···
 /* This is called w/ inode->i_mutex downed */
 int reiserfs_delete_xattrs(struct inode *inode)
 {
-	struct file *fp;
 	struct dentry *dir, *root;
 	int err = 0;
 
···
 		return 0;
 	}
 
-	fp = dentry_open(dir, NULL, O_RDWR);
-	if (IS_ERR(fp)) {
-		err = PTR_ERR(fp);
-		/* dentry_open dputs the dentry if it fails */
-		goto out;
-	}
-
 	lock_kernel();
-	err = xattr_readdir(fp, reiserfs_delete_xattrs_filler, dir);
+	err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir);
 	if (err) {
 		unlock_kernel();
 		goto out_dir;
···
 	unlock_kernel();
 
       out_dir:
-	fput(fp);
+	dput(dir);
 
       out:
 	if (!err)
···
 
 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
 {
-	struct file *fp;
 	struct dentry *dir;
 	int err = 0;
 	struct reiserfs_chown_buf buf;
···
 		goto out;
 	}
 
-	fp = dentry_open(dir, NULL, O_RDWR);
-	if (IS_ERR(fp)) {
-		err = PTR_ERR(fp);
-		/* dentry_open dputs the dentry if it fails */
-		goto out;
-	}
-
 	lock_kernel();
 
 	attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME);
···
 	buf.attrs = attrs;
 	buf.inode = inode;
 
-	err = xattr_readdir(fp, reiserfs_chown_xattrs_filler, &buf);
+	err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf);
 	if (err) {
 		unlock_kernel();
 		goto out_dir;
···
 	unlock_kernel();
 
       out_dir:
-	fput(fp);
+	dput(dir);
 
       out:
 	attrs->ia_valid = ia_valid;
···
  */
 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
 {
-	struct file *fp;
 	struct dentry *dir;
 	int err = 0;
 	struct reiserfs_listxattr_buf buf;
···
 		goto out;
 	}
 
-	fp = dentry_open(dir, NULL, O_RDWR);
-	if (IS_ERR(fp)) {
-		err = PTR_ERR(fp);
-		/* dentry_open dputs the dentry if it fails */
-		goto out;
-	}
-
 	buf.r_buf = buffer;
 	buf.r_size = buffer ? size : 0;
 	buf.r_pos = 0;
···
 
 	REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir;
 
-	err = xattr_readdir(fp, reiserfs_listxattr_filler, &buf);
+	err = xattr_readdir(dir->d_inode, reiserfs_listxattr_filler, &buf);
 	if (err)
 		goto out_dir;
 
···
 		err = buf.r_pos;
 
       out_dir:
-	fput(fp);
+	dput(dir);
 
       out:
 	reiserfs_read_unlock_xattr_i(dentry->d_inode);