From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: find_fh_dentry returned a DISCONNECTED directory Date: Thu, 13 Feb 2014 16:27:01 -0500 Message-ID: <20140213212701.GB21982@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org To: jbacik@fb.com Return-path: Received: from fieldses.org ([174.143.236.118]:52943 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751277AbaBMV1D (ORCPT ); Thu, 13 Feb 2014 16:27:03 -0500 Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Yesterday you passed on a report of this printk from nfsdfh.c firing: printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n", dentry); I think the dentry probably comes from the FILEID_ROOT case of: if (fileid_type == FILEID_ROOT) dentry = dget(exp->ex_path.dentry); else { dentry = exportfs_decode_fh(exp->ex_path.mnt, fid, data_left, fileid_type, nfsd_acceptable, exp); } In that case the dentry was found using ordinary filesystem lookups, so doesn't go through the same DISCONNECTED-clearing logic as in the case of lookups by filehandle. Probably they have an export root that's not a filesystem root, and the lookups happened in the right order? I suspect that's fine, and that the printk is just stupid, but maybe we should clear DISCONNECTED when possible on normal lookups. The following is my attempt, though I'm not sure if d_alloc is the right place to do this. In any case it might help confirm this is what's happening. So if you pass along this patch to the person who was seeing that printk I'd be interested in the results. --b. commit 49fc5637ca951d2add808a695768512f8b5bd7ad Author: J. Bruce Fields Date: Thu Feb 13 14:04:43 2014 -0500 dcache: clear DCACHE_DISCONNECTED on child when cleared on parent Currently DCACHE_DISCONNECTED is only cleared by the filehandle lookup code. That's OK, it's only the filehandle code that really cares about this flag. But it might be kinder to also clear DCACHE_DISCONNECTED on regular lookups when we notice it's appropriate. Signed-off-by: J. Bruce Fields diff --git a/fs/dcache.c b/fs/dcache.c index 265e0ce..c4a9478 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1534,6 +1534,16 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) return dentry; } +static void d_inherit_connected(struct dentry *dentry) +{ + /* + * If the parent is connected, then the child is too. (But if + * DISCONNECTED is set, that doesn't tell us anything certain.) + */ + if (!(dentry->d_parent->d_flags & DCACHE_DISCONNECTED)) + dentry->d_flags &= ~DCACHE_DISCONNECTED; +} + /** * d_alloc - allocate a dcache entry * @parent: parent of entry to allocate @@ -1556,6 +1566,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) */ __dget_dlock(parent); dentry->d_parent = parent; + d_inherit_connected(dentry); list_add(&dentry->d_u.d_child, &parent->d_subdirs); spin_unlock(&parent->d_lock);