Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755801AbYAJCR2 (ORCPT ); Wed, 9 Jan 2008 21:17:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756816AbYAJCRA (ORCPT ); Wed, 9 Jan 2008 21:17:00 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:37445 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756513AbYAJCQ6 (ORCPT ); Wed, 9 Jan 2008 21:16:58 -0500 From: Erez Zadok To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@ftp.linux.org.uk, hch@infradead.org, Erez Zadok Subject: [PATCH 3/4] Unionfs: branch-management related locking fixes Date: Wed, 9 Jan 2008 21:16:31 -0500 Message-Id: <11999313944186-git-send-email-ezk@cs.sunysb.edu> X-Mailer: git-send-email 1.5.2.2 X-MailKey: Erez_Zadok In-Reply-To: <1199931392670-git-send-email-ezk@cs.sunysb.edu> References: <1199931392670-git-send-email-ezk@cs.sunysb.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4106 Lines: 116 Add necessary locking to dentry/inode branch-configuration, so we get consistent values during branch-management actions. In d_revalidate_chain, ->permission, and ->create, also lock parent dentry. Signed-off-by: Erez Zadok --- fs/unionfs/commonfops.c | 6 ++++++ fs/unionfs/dentry.c | 6 +++++- fs/unionfs/inode.c | 17 +++++++++++++++++ 3 files changed, 28 insertions(+), 1 deletions(-) diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c index 2c32ada..f37192f 100644 --- a/fs/unionfs/commonfops.c +++ b/fs/unionfs/commonfops.c @@ -318,6 +318,7 @@ int unionfs_file_revalidate(struct file *file, bool willwrite) * First revalidate the dentry inside struct file, * but not unhashed dentries. */ +reval_dentry: if (unlikely(!d_deleted(dentry) && !__unionfs_d_revalidate_chain(dentry, NULL, willwrite))) { err = -ESTALE; @@ -328,6 +329,11 @@ int unionfs_file_revalidate(struct file *file, bool willwrite) dgen = atomic_read(&UNIONFS_D(dentry)->generation); fgen = atomic_read(&UNIONFS_F(file)->generation); + if (unlikely(sbgen > dgen)) { + pr_debug("unionfs: retry dentry revalidation\n"); + schedule(); + goto reval_dentry; + } BUG_ON(sbgen > dgen); /* diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c index 7646828..d969640 100644 --- a/fs/unionfs/dentry.c +++ b/fs/unionfs/dentry.c @@ -203,7 +203,7 @@ bool is_newer_lower(const struct dentry *dentry) if (!dentry || !UNIONFS_D(dentry)) return false; inode = dentry->d_inode; - if (!inode || !UNIONFS_I(inode) || + if (!inode || !UNIONFS_I(inode)->lower_inodes || ibstart(inode) < 0 || ibend(inode) < 0) return false; @@ -295,6 +295,8 @@ bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd, chain_len = 0; sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation); dtmp = dentry->d_parent; + if (dentry != dtmp) + unionfs_lock_dentry(dtmp, UNIONFS_DMUTEX_REVAL_PARENT); dgen = atomic_read(&UNIONFS_D(dtmp)->generation); /* XXX: should we check if is_newer_lower all the way up? */ if (unlikely(is_newer_lower(dtmp))) { @@ -315,6 +317,8 @@ bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd, } purge_inode_data(dtmp->d_inode); } + if (dentry != dtmp) + unionfs_unlock_dentry(dtmp); while (sbgen != dgen) { /* The root entry should always be valid */ BUG_ON(IS_ROOT(dtmp)); diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c index 6095c4f..e15ddb9 100644 --- a/fs/unionfs/inode.c +++ b/fs/unionfs/inode.c @@ -30,6 +30,13 @@ static int unionfs_create(struct inode *parent, struct dentry *dentry, struct nameidata lower_nd; unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD); + unionfs_lock_dentry(dentry->d_parent, UNIONFS_DMUTEX_PARENT); + valid = __unionfs_d_revalidate_chain(dentry->d_parent, nd, false); + unionfs_unlock_dentry(dentry->d_parent); + if (unlikely(!valid)) { + err = -ESTALE; /* same as what real_lookup does */ + goto out; + } unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD); valid = __unionfs_d_revalidate_chain(dentry, nd, false); @@ -936,6 +943,14 @@ static int unionfs_permission(struct inode *inode, int mask, const int is_file = !S_ISDIR(inode->i_mode); const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ); + if (nd) + unionfs_lock_dentry(nd->dentry, UNIONFS_DMUTEX_CHILD); + + if (!UNIONFS_I(inode)->lower_inodes) { + if (is_file) /* dirs can be unlinked but chdir'ed to */ + err = -ESTALE; /* force revalidate */ + goto out; + } bstart = ibstart(inode); bend = ibend(inode); if (unlikely(bstart < 0 || bend < 0)) { @@ -1003,6 +1018,8 @@ static int unionfs_permission(struct inode *inode, int mask, out: unionfs_check_inode(inode); unionfs_check_nd(nd); + if (nd) + unionfs_unlock_dentry(nd->dentry); return err; } -- 1.5.2.2 -- 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/