Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964880AbWIABo1 (ORCPT ); Thu, 31 Aug 2006 21:44:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964879AbWIABo0 (ORCPT ); Thu, 31 Aug 2006 21:44:26 -0400 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:55942 "EHLO filer.fsl.cs.sunysb.edu") by vger.kernel.org with ESMTP id S964877AbWIABoZ (ORCPT ); Thu, 31 Aug 2006 21:44:25 -0400 Date: Thu, 31 Aug 2006 21:44:14 -0400 From: Josef Sipek To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, hch@infradead.org, akpm@osdl.org, viro@ftp.linux.org.uk Subject: [PATCH 06/22][RFC] Unionfs: Dentry operations Message-ID: <20060901014414.GG5788@fsl.cs.sunysb.edu> References: <20060901013512.GA5788@fsl.cs.sunysb.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060901013512.GA5788@fsl.cs.sunysb.edu> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7565 Lines: 258 From: Josef "Jeff" Sipek This patch contains the dentry operations for Unionfs. Signed-off-by: Josef "Jeff" Sipek Signed-off-by: David Quigley Signed-off-by: Erez Zadok --- fs/unionfs/dentry.c | 236 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 236 insertions(+) diff -Nur -x linux-2.6-git/Documentation/dontdiff linux-2.6-git/fs/unionfs/dentry.c linux-2.6-git-unionfs/fs/unionfs/dentry.c --- linux-2.6-git/fs/unionfs/dentry.c 1969-12-31 19:00:00.000000000 -0500 +++ linux-2.6-git-unionfs/fs/unionfs/dentry.c 2006-08-31 19:04:00.000000000 -0400 @@ -0,0 +1,236 @@ +/* + * Copyright (c) 2003-2006 Erez Zadok + * Copyright (c) 2003-2006 Charles P. Wright + * Copyright (c) 2005-2006 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) 2003-2006 Stony Brook University + * Copyright (c) 2003-2006 The Research Foundation of State University of New York + * + * For specific licensing information, see the COPYING file distributed with + * this package. + * + * This Copyright notice must be kept intact and distributed with all sources. + */ + +#include "union.h" + +/* declarations added for "sparse" */ +extern int unionfs_d_revalidate_wrap(struct dentry *dentry, + struct nameidata *nd); +extern void unionfs_d_release(struct dentry *dentry); +extern void unionfs_d_iput(struct dentry *dentry, struct inode *inode); + +/* + * THIS IS A BOOLEAN FUNCTION: returns 1 if valid, 0 otherwise. + */ +int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + int valid = 1; /* default is valid (1); invalid is 0. */ + struct dentry *hidden_dentry; + int bindex, bstart, bend; + int sbgen, dgen; + int positive = 0; + int locked = 0; + int restart = 0; + int interpose_flag; + +restart: + verify_locked(dentry); + + /* if the dentry is unhashed, do NOT revalidate */ + if (d_deleted(dentry)) { + printk(KERN_DEBUG "unhashed dentry being revalidated: %*s\n", + dentry->d_name.len, dentry->d_name.name); + goto out; + } + + BUG_ON(dbstart(dentry) == -1); + if (dentry->d_inode) + positive = 1; + dgen = atomic_read(&dtopd(dentry)->udi_generation); + sbgen = atomic_read(&stopd(dentry->d_sb)->usi_generation); + /* If we are working on an unconnected dentry, then there is no + * revalidation to be done, because this file does not exist within the + * namespace, and Unionfs operates on the namespace, not data. + */ + if (sbgen != dgen) { + struct dentry *result; + int pdgen; + + unionfs_read_lock(dentry->d_sb); + locked = 1; + + /* The root entry should always be valid */ + BUG_ON(IS_ROOT(dentry)); + + /* We can't work correctly if our parent isn't valid. */ + pdgen = atomic_read(&dtopd(dentry->d_parent)->udi_generation); + if (!restart && (pdgen != sbgen)) { + unionfs_read_unlock(dentry->d_sb); + locked = 0; + /* We must be locked before our parent. */ + if (! + (dentry->d_parent->d_op-> + d_revalidate(dentry->d_parent, nd))) { + valid = 0; + goto out; + } + restart = 1; + goto restart; + } + BUG_ON(pdgen != sbgen); + + /* Free the pointers for our inodes and this dentry. */ + bstart = dbstart(dentry); + bend = dbend(dentry); + if (bstart >= 0) { + struct dentry *hidden_dentry; + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = + dtohd_index_nocheck(dentry, bindex); + if (!hidden_dentry) + continue; + dput(hidden_dentry); + } + } + set_dbstart(dentry, -1); + set_dbend(dentry, -1); + + interpose_flag = INTERPOSE_REVAL_NEG; + if (positive) { + interpose_flag = INTERPOSE_REVAL; + mutex_lock(&dentry->d_inode->i_mutex); + bstart = ibstart(dentry->d_inode); + bend = ibend(dentry->d_inode); + if (bstart >= 0) { + struct inode *hidden_inode; + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_inode = + itohi_index(dentry->d_inode, + bindex); + if (!hidden_inode) + continue; + iput(hidden_inode); + } + } + kfree(itohi_ptr(dentry->d_inode)); + itohi_ptr(dentry->d_inode) = NULL; + ibstart(dentry->d_inode) = -1; + ibend(dentry->d_inode) = -1; + mutex_unlock(&dentry->d_inode->i_mutex); + } + + result = unionfs_lookup_backend(dentry, interpose_flag); + if (result) { + if (IS_ERR(result)) { + valid = 0; + goto out; + } + /* current unionfs_lookup_backend() doesn't return + a valid dentry */ + dput(dentry); + dentry = result; + } + + if (positive && itopd(dentry->d_inode)->uii_stale) { + make_stale_inode(dentry->d_inode); + d_drop(dentry); + valid = 0; + goto out; + } + goto out; + } + + /* The revalidation must occur across all branches */ + bstart = dbstart(dentry); + bend = dbend(dentry); + BUG_ON(bstart == -1); + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = dtohd_index(dentry, bindex); + if (!hidden_dentry || !hidden_dentry->d_op + || !hidden_dentry->d_op->d_revalidate) + continue; + + if (!hidden_dentry->d_op->d_revalidate(hidden_dentry, nd)) + valid = 0; + } + + if (!dentry->d_inode) + valid = 0; + if (valid) + fist_copy_attr_all(dentry->d_inode, itohi(dentry->d_inode)); + +out: + if (locked) + unionfs_read_unlock(dentry->d_sb); + return valid; +} + +int unionfs_d_revalidate_wrap(struct dentry *dentry, struct nameidata *nd) +{ + int err; + + lock_dentry(dentry); + + err = unionfs_d_revalidate(dentry, nd); + + unlock_dentry(dentry); + return err; +} + +void unionfs_d_release(struct dentry *dentry) +{ + struct dentry *hidden_dentry; + int bindex, bstart, bend; + + /* There is no reason to lock the dentry, because we have the only + * reference, but the printing functions verify that we have a lock + * on the dentry before calling dbstart, etc. */ + lock_dentry(dentry); + + /* this could be a negative dentry, so check first */ + if (!dtopd(dentry)) { + printk(KERN_DEBUG "dentry without private data: %*s", + dentry->d_name.len, dentry->d_name.name); + goto out; + } else if (dbstart(dentry) < 0) { + /* this is due to a failed lookup */ + /* the failed lookup has a dtohd_ptr set to null, + but this is a better check */ + printk(KERN_DEBUG "dentry without hidden dentries : %*s", + dentry->d_name.len, dentry->d_name.name); + goto out_free; + } + + /* Release all the hidden dentries */ + bstart = dbstart(dentry); + bend = dbend(dentry); + for (bindex = bstart; bindex <= bend; bindex++) { + hidden_dentry = dtohd_index(dentry, bindex); + dput(hidden_dentry); + set_dtohd_index(dentry, bindex, NULL); + } + /* free private data (unionfs_dentry_info) here */ + kfree(dtohd_ptr(dentry)); + dtohd_ptr(dentry) = NULL; + +out_free: + /* No need to unlock it, because it is disappeared. */ + free_dentry_private_data(dtopd(dentry)); + dtopd_lhs(dentry) = NULL; /* just to be safe */ + +out: + /* This is here to make the compiler happy */ + return; +} + +struct dentry_operations unionfs_dops = { + .d_revalidate = unionfs_d_revalidate_wrap, + .d_release = unionfs_d_release, +}; + - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/