Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030527AbXAHEUA (ORCPT ); Sun, 7 Jan 2007 23:20:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030523AbXAHETi (ORCPT ); Sun, 7 Jan 2007 23:19:38 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:50441 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030492AbXAHES6 (ORCPT ); Sun, 7 Jan 2007 23:18:58 -0500 From: "Josef 'Jeff' Sipek" To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, hch@infradead.org, viro@ftp.linux.org.uk, torvalds@osdl.org, akpm@osdl.org, mhalcrow@us.ibm.com, Josef "Jeff" Sipek , David Quigley , Erez Zadok Subject: [PATCH 06/24] Unionfs: Dentry operations Date: Sun, 7 Jan 2007 23:12:58 -0500 Message-Id: <11682295974095-git-send-email-jsipek@cs.sunysb.edu> X-Mailer: git-send-email 1.4.4.2 In-Reply-To: <1168229596580-git-send-email-jsipek@cs.sunysb.edu> References: <1168229596580-git-send-email-jsipek@cs.sunysb.edu> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7714 Lines: 268 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 | 243 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 243 insertions(+), 0 deletions(-) diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c new file mode 100644 index 0000000..740c000 --- /dev/null +++ b/fs/unionfs/dentry.c @@ -0,0 +1,243 @@ +/* + * 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 + * + * 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" + +/* 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); + +/* + * 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; + + struct nameidata lowernd; /* TODO: be gentler to the stack */ + + if (nd) + memcpy(&lowernd, nd, sizeof(struct nameidata)); + else + memset(&lowernd, 0, sizeof(struct nameidata)); + +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(&UNIONFS_D(dentry)->generation); + sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->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(&UNIONFS_D(dentry->d_parent)->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 = + unionfs_lower_dentry_idx(dentry, bindex); + 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 = + unionfs_lower_inode_idx(dentry->d_inode, + bindex); + iput(hidden_inode); + } + } + kfree(UNIONFS_I(dentry->d_inode)->lower_inodes); + UNIONFS_I(dentry->d_inode)->lower_inodes = NULL; + ibstart(dentry->d_inode) = -1; + ibend(dentry->d_inode) = -1; + mutex_unlock(&dentry->d_inode->i_mutex); + } + + result = unionfs_lookup_backend(dentry, &lowernd, 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 && UNIONFS_I(dentry->d_inode)->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 = unionfs_lower_dentry_idx(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) { + fsstack_copy_attr_all(dentry->d_inode, + unionfs_lower_inode(dentry->d_inode), + unionfs_get_nlinks); + fsstack_copy_inode_size(dentry->d_inode, + unionfs_lower_inode(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) +{ + 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 (!UNIONFS_D(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 */ + 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++) { + dput(unionfs_lower_dentry_idx(dentry, bindex)); + mntput(unionfs_lower_mnt_idx(dentry, bindex)); + + unionfs_set_lower_dentry_idx(dentry, bindex, NULL); + unionfs_set_lower_mnt_idx(dentry, bindex, NULL); + } + /* free private data (unionfs_dentry_info) here */ + kfree(UNIONFS_D(dentry)->lower_paths); + UNIONFS_D(dentry)->lower_paths = NULL; + +out_free: + /* No need to unlock it, because it is disappeared. */ + free_dentry_private_data(UNIONFS_D(dentry)); + dentry->d_fsdata = NULL; /* just to be safe */ + +out: + return; +} + +struct dentry_operations unionfs_dops = { + .d_revalidate = unionfs_d_revalidate_wrap, + .d_release = unionfs_d_release, +}; + -- 1.4.4.2 - 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/