Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754142AbYG3Co5 (ORCPT ); Tue, 29 Jul 2008 22:44:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753735AbYG3CoT (ORCPT ); Tue, 29 Jul 2008 22:44:19 -0400 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:46237 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753074AbYG3CoQ (ORCPT ); Tue, 29 Jul 2008 22:44:16 -0400 From: Erez Zadok To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, hch@infradead.org, miklos@szeredi.hu, Erez Zadok Subject: [PATCH 10/19] Unionfs: cache coherency fixes Date: Tue, 29 Jul 2008 22:43:40 -0400 Message-Id: <12173858381175-git-send-email-ezk@cs.sunysb.edu> X-Mailer: git-send-email 1.5.2.2 X-MailKey: Erez_Zadok In-Reply-To: <12173858291233-git-send-email-ezk@cs.sunysb.edu> References: <12173858291233-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: 5338 Lines: 163 Handle unhashed or silly-renamed lower dentries properly. Signed-off-by: Erez Zadok --- fs/unionfs/commonfops.c | 3 +- fs/unionfs/debug.c | 2 +- fs/unionfs/dentry.c | 49 +++++++++++++++++++++++++++++++++++++++++----- fs/unionfs/main.c | 3 -- 4 files changed, 46 insertions(+), 11 deletions(-) diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c index df002d5..d64272b 100644 --- a/fs/unionfs/commonfops.c +++ b/fs/unionfs/commonfops.c @@ -466,7 +466,8 @@ reval_dentry: dgen = atomic_read(&UNIONFS_D(dentry)->generation); if (unlikely(sbgen > dgen)) { - pr_debug("unionfs: retry (locked) dentry revalidation\n"); + pr_debug("unionfs: retry (locked) dentry %s revalidation\n", + dentry->d_name.name); schedule(); goto reval_dentry; } diff --git a/fs/unionfs/debug.c b/fs/unionfs/debug.c index d154c32..4da4f0b 100644 --- a/fs/unionfs/debug.c +++ b/fs/unionfs/debug.c @@ -313,7 +313,7 @@ check_inode: } } /* check if lower inode is newer than upper one (it shouldn't) */ - if (unlikely(is_newer_lower(dentry))) { + if (unlikely(is_newer_lower(dentry) && !is_negative_lower(dentry))) { PRINT_CALLER(fname, fxn, line); for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) { diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c index cd4611b..dfa4755 100644 --- a/fs/unionfs/dentry.c +++ b/fs/unionfs/dentry.c @@ -23,11 +23,16 @@ bool is_negative_lower(const struct dentry *dentry) int bindex; struct dentry *lower_dentry; - BUG_ON(!dentry || dbstart(dentry) < 0); + BUG_ON(!dentry); + /* cache coherency: check if file was deleted on lower branch */ + if (dbstart(dentry) < 0) + return true; for (bindex = dbstart(dentry); bindex <= dbend(dentry); bindex++) { lower_dentry = unionfs_lower_dentry_idx(dentry, bindex); - /* XXX: what if lower_dentry is NULL? */ - if (lower_dentry && lower_dentry->d_inode) + /* unhashed (i.e., unlinked) lower dentries don't count */ + if (lower_dentry && lower_dentry->d_inode && + !d_deleted(lower_dentry) && + !(lower_dentry->d_flags & DCACHE_NFSFS_RENAMED)) return false; } return true; @@ -75,6 +80,7 @@ static bool __unionfs_d_revalidate_one(struct dentry *dentry, verify_locked(dentry); verify_locked(dentry->d_parent); + sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation); /* if the dentry is unhashed, do NOT revalidate */ if (d_deleted(dentry)) goto out; @@ -83,7 +89,6 @@ static bool __unionfs_d_revalidate_one(struct dentry *dentry, 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 @@ -103,6 +108,21 @@ static bool __unionfs_d_revalidate_one(struct dentry *dentry, /* Free the pointers for our inodes and this dentry. */ bstart = dbstart(dentry); bend = dbend(dentry); + + /* + * mntput unhashed lower dentries, because those files got + * deleted or rmdir'ed. + */ + for (bindex = bstart; bindex <= bend; bindex++) { + lower_dentry = unionfs_lower_dentry_idx(dentry, bindex); + if (!lower_dentry) + continue; + if (!d_deleted(lower_dentry) && + !(lower_dentry->d_flags & DCACHE_NFSFS_RENAMED)) + continue; + unionfs_mntput(dentry, bindex); + } + __dput_lowers(dentry, bstart, bend); dbstart(dentry) = dbend(dentry) = -1; @@ -112,8 +132,12 @@ static bool __unionfs_d_revalidate_one(struct dentry *dentry, iput_lowers_all(dentry->d_inode, true); } - result = unionfs_lookup_backend(dentry, &lowernd, - interpose_flag); + if (realloc_dentry_private_data(dentry) != 0) { + valid = false; + goto out; + } + + result = unionfs_lookup_full(dentry, &lowernd, interpose_flag); if (result) { if (IS_ERR(result)) { valid = false; @@ -179,6 +203,9 @@ static bool __unionfs_d_revalidate_one(struct dentry *dentry, } out: + if (valid) + atomic_set(&UNIONFS_D(dentry)->generation, sbgen); + return valid; } @@ -241,6 +268,16 @@ bool is_newer_lower(const struct dentry *dentry) return true; } } + + /* + * Last check: if this is a positive dentry, but somehow all lower + * dentries are negative or unhashed, then this dentry needs to be + * revalidated, because someone probably deleted the objects from + * the lower branches directly. + */ + if (is_negative_lower(dentry)) + return true; + return false; /* default: lower is not newer */ } diff --git a/fs/unionfs/main.c b/fs/unionfs/main.c index a9d2cb6..1fd67c6 100644 --- a/fs/unionfs/main.c +++ b/fs/unionfs/main.c @@ -88,9 +88,6 @@ struct dentry *unionfs_interpose(struct dentry *dentry, struct super_block *sb, verify_locked(dentry); - /* Make sure that we didn't get a negative dentry. */ - BUG_ON(is_negative_lower(dentry)); - /* * We allocate our new inode below by calling unionfs_iget, * which will initialize some of the new inode's fields -- 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/