From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bhuna.collabora.co.uk ([46.235.227.227]:39396 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751748AbeEVUiO (ORCPT ); Tue, 22 May 2018 16:38:14 -0400 From: Gabriel Krisman Bertazi To: viro@ZenIV.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, Gabriel Krisman Bertazi Subject: [PATCH NOMERGE 05/13] vfs: Handle case-exact lookup in d_add_ci Date: Tue, 22 May 2018 17:38:10 -0300 Message-Id: <20180522203818.14666-6-krisman@collabora.co.uk> In-Reply-To: <20180522203818.14666-1-krisman@collabora.co.uk> References: <20180522203818.14666-1-krisman@collabora.co.uk> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: This prevents a soft hang if called d_add_ci is called from the FS layer, when doing a CI search but the result dentry is the exact match. Signed-off-by: Gabriel Krisman Bertazi --- fs/dcache.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 4bd28d7caa53..30c5eff31e88 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2049,6 +2049,20 @@ struct dentry *d_obtain_root(struct inode *inode) } EXPORT_SYMBOL(d_obtain_root); +static inline bool d_same_name(const struct dentry *dentry, + const struct dentry *parent, + const struct qstr *name) +{ + if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) { + if (dentry->d_name.len != name->len) + return false; + return dentry_cmp(dentry, name->name, name->len) == 0; + } + return parent->d_op->d_compare(dentry, + dentry->d_name.len, dentry->d_name.name, + name) == 0; +} + static inline bool d_same_name_ci(const struct dentry *dentry, const struct dentry *parent, const struct qstr *name) @@ -2080,6 +2094,10 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, { struct dentry *found, *res; + /* Trivial case: CI search is exact match. */ + if (d_same_name(dentry, dentry->d_parent, name)) + return d_splice_alias(inode, dentry); + /* * First check if a dentry matching the name already exists, * if not go ahead and create it now. @@ -2112,21 +2130,6 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, } EXPORT_SYMBOL(d_add_ci); - -static inline bool d_same_name(const struct dentry *dentry, - const struct dentry *parent, - const struct qstr *name) -{ - if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) { - if (dentry->d_name.len != name->len) - return false; - return dentry_cmp(dentry, name->name, name->len) == 0; - } - return parent->d_op->d_compare(dentry, - dentry->d_name.len, dentry->d_name.name, - name) == 0; -} - /** * __d_lookup_rcu - search for a dentry (racy, store-free) * @parent: parent dentry -- 2.17.0