From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755657AbXLJCrK (ORCPT ); Sun, 9 Dec 2007 21:47:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754747AbXLJCnP (ORCPT ); Sun, 9 Dec 2007 21:43:15 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:49748 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751653AbXLJCnG (ORCPT ); Sun, 9 Dec 2007 21:43:06 -0500 From: Erez Zadok To: hch@infradead.org, viro@ftp.linux.org.uk, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Erez Zadok Subject: [PATCH 22/42] Unionfs: unlink/rmdir operations Date: Sun, 9 Dec 2007 21:41:55 -0500 Message-Id: <1197254548999-git-send-email-ezk@cs.sunysb.edu> X-Mailer: git-send-email 1.5.2.2 X-MailKey: Erez_Zadok In-Reply-To: <11972545353262-git-send-email-ezk@cs.sunysb.edu> References: <11972545353262-git-send-email-ezk@cs.sunysb.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Erez Zadok --- fs/unionfs/unlink.c | 236 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 236 insertions(+), 0 deletions(-) create mode 100644 fs/unionfs/unlink.c diff --git a/fs/unionfs/unlink.c b/fs/unionfs/unlink.c new file mode 100644 index 0000000..423ff36 --- /dev/null +++ b/fs/unionfs/unlink.c @@ -0,0 +1,236 @@ +/* + * Copyright (c) 2003-2007 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2007 Josef 'Jeff' Sipek + * Copyright (c) 2005-2006 Junjiro Okajima + * Copyright (c) 2005 Arun M. Krishnakumar + * Copyright (c) 2004-2006 David P. Quigley + * Copyright (c) 2003-2004 Mohammad Nayyer Zubair + * Copyright (c) 2003 Puja Gupta + * Copyright (c) 2003 Harikesavan Krishnan + * Copyright (c) 2003-2007 Stony Brook University + * Copyright (c) 2003-2007 The Research Foundation of SUNY + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "union.h" + +/* unlink a file by creating a whiteout */ +static int unionfs_unlink_whiteout(struct inode *dir, struct dentry *dentry) +{ + struct dentry *lower_dentry; + struct dentry *lower_dir_dentry; + int bindex; + int err = 0; + + err = unionfs_partial_lookup(dentry); + if (err) + goto out; + + bindex = dbstart(dentry); + + lower_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!lower_dentry) + goto out; + + lower_dir_dentry = lock_parent(lower_dentry); + + /* avoid destroying the lower inode if the file is in use */ + dget(lower_dentry); + err = is_robranch_super(dentry->d_sb, bindex); + if (!err) + err = vfs_unlink(lower_dir_dentry->d_inode, lower_dentry); + /* if vfs_unlink succeeded, update our inode's times */ + if (!err) + unionfs_copy_attr_times(dentry->d_inode); + dput(lower_dentry); + fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); + unlock_dir(lower_dir_dentry); + + if (err && !IS_COPYUP_ERR(err)) + goto out; + + /* + * We create whiteouts if (1) there was an error unlinking the main + * file; (2) there is a lower priority file with the same name + * (dbopaque); (3) the branch in which the file is not the last + * (rightmost0 branch. The last rule is an optimization to avoid + * creating all those whiteouts if there's no chance they'd be + * masking any lower-priority branch, as well as unionfs is used + * with only one branch (using only one branch, while odd, is still + * possible). + */ + if (err) { + if (dbstart(dentry) == 0) + goto out; + err = create_whiteout(dentry, dbstart(dentry) - 1); + } else if (dbopaque(dentry) != -1) { + err = create_whiteout(dentry, dbopaque(dentry)); + } else if (dbstart(dentry) < sbend(dentry->d_sb)) { + err = create_whiteout(dentry, dbstart(dentry)); + } + +out: + if (!err) + dentry->d_inode->i_nlink--; + + /* We don't want to leave negative leftover dentries for revalidate. */ + if (!err && (dbopaque(dentry) != -1)) + update_bstart(dentry); + + return err; +} + +int unionfs_unlink(struct inode *dir, struct dentry *dentry) +{ + int err = 0; + + unionfs_read_lock(dentry->d_sb); + unionfs_lock_dentry(dentry); + + if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) { + err = -ESTALE; + goto out; + } + unionfs_check_dentry(dentry); + + err = unionfs_unlink_whiteout(dir, dentry); + /* call d_drop so the system "forgets" about us */ + if (!err) { + if (!S_ISDIR(dentry->d_inode->i_mode)) + unionfs_postcopyup_release(dentry); + d_drop(dentry); + /* + * if unlink/whiteout succeeded, parent dir mtime has + * changed + */ + unionfs_copy_attr_times(dir); + } + +out: + if (!err) { + unionfs_check_dentry(dentry); + unionfs_check_inode(dir); + } + unionfs_unlock_dentry(dentry); + unionfs_read_unlock(dentry->d_sb); + return err; +} + +static int unionfs_rmdir_first(struct inode *dir, struct dentry *dentry, + struct unionfs_dir_state *namelist) +{ + int err; + struct dentry *lower_dentry; + struct dentry *lower_dir_dentry = NULL; + + /* Here we need to remove whiteout entries. */ + err = delete_whiteouts(dentry, dbstart(dentry), namelist); + if (err) + goto out; + + lower_dentry = unionfs_lower_dentry(dentry); + + lower_dir_dentry = lock_parent(lower_dentry); + + /* avoid destroying the lower inode if the file is in use */ + dget(lower_dentry); + err = is_robranch(dentry); + if (!err) + err = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); + dput(lower_dentry); + + fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); + /* propagate number of hard-links */ + dentry->d_inode->i_nlink = unionfs_get_nlinks(dentry->d_inode); + +out: + if (lower_dir_dentry) + unlock_dir(lower_dir_dentry); + return err; +} + +int unionfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + int err = 0; + struct unionfs_dir_state *namelist = NULL; + int dstart, dend; + + unionfs_read_lock(dentry->d_sb); + unionfs_lock_dentry(dentry); + + if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) { + err = -ESTALE; + goto out; + } + unionfs_check_dentry(dentry); + + /* check if this unionfs directory is empty or not */ + err = check_empty(dentry, &namelist); + if (err) + goto out; + + err = unionfs_rmdir_first(dir, dentry, namelist); + dstart = dbstart(dentry); + dend = dbend(dentry); + /* + * We create a whiteout for the directory if there was an error to + * rmdir the first directory entry in the union. Otherwise, we + * create a whiteout only if there is no chance that a lower + * priority branch might also have the same named directory. IOW, + * if there is not another same-named directory at a lower priority + * branch, then we don't need to create a whiteout for it. + */ + if (!err) { + if (dstart < dend) + err = create_whiteout(dentry, dstart); + } else { + int new_err; + + if (dstart == 0) + goto out; + + /* exit if the error returned was NOT -EROFS */ + if (!IS_COPYUP_ERR(err)) + goto out; + + new_err = create_whiteout(dentry, dstart - 1); + if (new_err != -EEXIST) + err = new_err; + } + +out: + /* + * Drop references to lower dentry/inode so storage space for them + * can be reclaimed. Then, call d_drop so the system "forgets" + * about us. + */ + if (!err) { + struct inode *inode = dentry->d_inode; + BUG_ON(!inode); + iput(unionfs_lower_inode_idx(inode, dstart)); + unionfs_set_lower_inode_idx(inode, dstart, NULL); + dput(unionfs_lower_dentry_idx(dentry, dstart)); + unionfs_set_lower_dentry_idx(dentry, dstart, NULL); + /* + * If the last directory is unlinked, then mark istart/end + * as -1, (to maintain the invariant that if there are no + * lower objects, then branch index start and end are set to + * -1). + */ + if (!unionfs_lower_inode_idx(inode, dstart) && + !unionfs_lower_inode_idx(inode, dend)) + ibstart(inode) = ibend(inode) = -1; + d_drop(dentry); + } + + if (namelist) + free_rdstate(namelist); + + unionfs_unlock_dentry(dentry); + unionfs_read_unlock(dentry->d_sb); + return err; +} -- 1.5.2.2