From patchwork Tue Jan 17 22:00:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paulo Alcantara X-Patchwork-Id: 1727790 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=cjr.nz header.i=@cjr.nz header.a=rsa-sha256 header.s=dkim header.b=fT0xKTD0; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by legolas.ozlabs.org (Postfix) with ESMTP id 4NxNgT2DVBz23gM for ; Wed, 18 Jan 2023 09:22:45 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229831AbjAQWWm (ORCPT ); Tue, 17 Jan 2023 17:22:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230122AbjAQWVL (ORCPT ); Tue, 17 Jan 2023 17:21:11 -0500 Received: from mx.cjr.nz (mx.cjr.nz [51.158.111.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99AA95B5B9 for ; Tue, 17 Jan 2023 14:00:54 -0800 (PST) Received: from authenticated-user (mx.cjr.nz [51.158.111.142]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pc) by mx.cjr.nz (Postfix) with ESMTPSA id D1DA880268; Tue, 17 Jan 2023 22:00:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cjr.nz; s=dkim; t=1673992853; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NUi4SYM8lfBX5Z1sKmXuOJbDfolhTaxdrUws4C3czWA=; b=fT0xKTD0702OVVl3y9l37COk755BjDohhDGzaIWqshnWr9eNDeqBrpfaSFTqcRUqtG6hbD vcsgsnhd88vpMQL9Exrg2AcvV6IIchNYCOyYr/OyfpOaa0WVrXSpnH2wUtpx5DfSn01VoP kKROe780ekz+vVG/QssIVlF8wNZRuLNnu2SI2OYL26lLqNoMn5kfCuc5k4M2v+dHk2bPCI FFU6VfuHD7meLt6RQh9Gx+jhwxQ2oDSZnpJIkk6H9jO4nsZSFv1kk28n1u7eS2fa17bXrQ 4lZv9/3pobaijm9vthmrwMVeA4gtqtxv9p5jGX2dVBjbNtaWB5FH4FoHbP9TuQ== From: Paulo Alcantara To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org, aurelien.aptel@gmail.com, Paulo Alcantara Subject: [PATCH v2 1/5] cifs: fix potential deadlock in cache_refresh_path() Date: Tue, 17 Jan 2023 19:00:37 -0300 Message-Id: <20230117220041.15905-2-pc@cjr.nz> In-Reply-To: <20230117220041.15905-1-pc@cjr.nz> References: <20230117000952.9965-1-pc@cjr.nz> <20230117220041.15905-1-pc@cjr.nz> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Avoid getting DFS referral from an exclusive lock in cache_refresh_path() because the tcon IPC used for getting the referral could be disconnected and thus causing a deadlock as shown below: task A task B ====== ====== cifs_demultiplex_thread() dfs_cache_find() cifs_handle_standard() cache_refresh_path() reconnect_dfs_server() down_write() dfs_cache_noreq_find() get_dfs_referral() down_read() <- deadlock smb2_get_dfs_refer() SMB2_ioctl() cifs_send_recv() compound_send_recv() wait_for_response() where task A cannot wake up task B because it is blocked on down_read() due to the exclusive lock held in cache_refresh_path() and therefore not being able to make progress. Fixes: c9f711039905 ("cifs: keep referral server sessions alive") Signed-off-by: Paulo Alcantara (SUSE) --- fs/cifs/dfs_cache.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-) diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index e20f8880363f..a6d7ae5f49a4 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -770,26 +770,27 @@ static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses, const */ static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, const char *path) { - int rc; - struct cache_entry *ce; struct dfs_info3_param *refs = NULL; + struct cache_entry *ce; int numrefs = 0; - bool newent = false; + int rc; cifs_dbg(FYI, "%s: search path: %s\n", __func__, path); - down_write(&htable_rw_lock); + down_read(&htable_rw_lock); ce = lookup_cache_entry(path); - if (!IS_ERR(ce)) { - if (!cache_entry_expired(ce)) { - dump_ce(ce); - up_write(&htable_rw_lock); - return 0; - } - } else { - newent = true; + if (!IS_ERR(ce) && !cache_entry_expired(ce)) { + up_read(&htable_rw_lock); + return 0; } + /* + * Unlock shared access as we don't want to hold any locks while getting + * a new referral. The @ses used for performing the I/O could be + * reconnecting and it acquires @htable_rw_lock to look up the dfs cache + * in order to failover -- if necessary. + */ + up_read(&htable_rw_lock); /* * Either the entry was not found, or it is expired. @@ -797,19 +798,22 @@ static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, cons */ rc = get_dfs_referral(xid, ses, path, &refs, &numrefs); if (rc) - goto out_unlock; + goto out; dump_refs(refs, numrefs); - if (!newent) { - rc = update_cache_entry_locked(ce, refs, numrefs); - goto out_unlock; + down_write(&htable_rw_lock); + /* Re-check as another task might have it added or refreshed already */ + ce = lookup_cache_entry(path); + if (!IS_ERR(ce)) { + if (cache_entry_expired(ce)) + rc = update_cache_entry_locked(ce, refs, numrefs); + } else { + rc = add_cache_entry_locked(refs, numrefs); } - rc = add_cache_entry_locked(refs, numrefs); - -out_unlock: up_write(&htable_rw_lock); +out: free_dfs_info_array(refs, numrefs); return rc; } From patchwork Tue Jan 17 22:00:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paulo Alcantara X-Patchwork-Id: 1727792 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=cjr.nz header.i=@cjr.nz header.a=rsa-sha256 header.s=dkim header.b=mLkutIPY; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by legolas.ozlabs.org (Postfix) with ESMTP id 4NxNht14ztz23gM for ; Wed, 18 Jan 2023 09:23:58 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229704AbjAQWXw (ORCPT ); Tue, 17 Jan 2023 17:23:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230126AbjAQWVL (ORCPT ); Tue, 17 Jan 2023 17:21:11 -0500 Received: from mx.cjr.nz (mx.cjr.nz [51.158.111.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9962261882 for ; Tue, 17 Jan 2023 14:00:56 -0800 (PST) Received: from authenticated-user (mx.cjr.nz [51.158.111.142]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pc) by mx.cjr.nz (Postfix) with ESMTPSA id 2D3B080CF7; Tue, 17 Jan 2023 22:00:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cjr.nz; s=dkim; t=1673992855; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bM1gJFc+tNJJwlTFw9QEOZDd0XBC1HlF9j/fpfhnEYw=; b=mLkutIPY6KBdEis5b58fcvQ89y9e/cB/YhO6iFaj+Se1z+JiyGXm5/lxWgdueeGkkv6Usz iWTK41AVEEIhyEe0F7t8zI29Unp40FAvjcJqLB5YuzZ5scc5b1fu2QgQXGWqEbPcc9x4Mq lm16D/pdif0ZafJbM1fYWXnNXvPPNFECvKBS1bBGsn7bIG19LAWprpGw4xR7yb92j0S7bj I+vRqDcou0hrakSjo2mxTvW6ZHwE96QAPzTgSpcIZqHga+ruDkDXfaFUAU3ZI8T34qSquQ p55qmoJ9l4swIHPimPvBNN+WowGdDBYGgSgONNPRyClhiLg+toANOIaNGS2r7A== From: Paulo Alcantara To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org, aurelien.aptel@gmail.com, Paulo Alcantara Subject: [PATCH v2 2/5] cifs: avoid re-lookups in dfs_cache_find() Date: Tue, 17 Jan 2023 19:00:38 -0300 Message-Id: <20230117220041.15905-3-pc@cjr.nz> In-Reply-To: <20230117220041.15905-1-pc@cjr.nz> References: <20230117000952.9965-1-pc@cjr.nz> <20230117220041.15905-1-pc@cjr.nz> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Simply downgrade the write lock on cache updates from cache_refresh_path() and avoid unnecessary re-lookup in dfs_cache_find(). Signed-off-by: Paulo Alcantara (SUSE) --- fs/cifs/dfs_cache.c | 58 ++++++++++++++++++++++++++------------------- 1 file changed, 34 insertions(+), 24 deletions(-) diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index a6d7ae5f49a4..755a00c4cba1 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -558,7 +558,8 @@ static void remove_oldest_entry_locked(void) } /* Add a new DFS cache entry */ -static int add_cache_entry_locked(struct dfs_info3_param *refs, int numrefs) +static struct cache_entry *add_cache_entry_locked(struct dfs_info3_param *refs, + int numrefs) { int rc; struct cache_entry *ce; @@ -573,11 +574,11 @@ static int add_cache_entry_locked(struct dfs_info3_param *refs, int numrefs) rc = cache_entry_hash(refs[0].path_name, strlen(refs[0].path_name), &hash); if (rc) - return rc; + return ERR_PTR(rc); ce = alloc_cache_entry(refs, numrefs); if (IS_ERR(ce)) - return PTR_ERR(ce); + return ce; spin_lock(&cache_ttl_lock); if (!cache_ttl) { @@ -594,7 +595,7 @@ static int add_cache_entry_locked(struct dfs_info3_param *refs, int numrefs) atomic_inc(&cache_count); - return 0; + return ce; } /* Check if two DFS paths are equal. @s1 and @s2 are expected to be in @cache_cp's charset */ @@ -767,8 +768,12 @@ static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses, const * * For interlinks, cifs_mount() and expand_dfs_referral() are supposed to * handle them properly. + * + * On success, return entry with acquired lock for reading, otherwise error ptr. */ -static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, const char *path) +static struct cache_entry *cache_refresh_path(const unsigned int xid, + struct cifs_ses *ses, + const char *path) { struct dfs_info3_param *refs = NULL; struct cache_entry *ce; @@ -780,10 +785,9 @@ static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, cons down_read(&htable_rw_lock); ce = lookup_cache_entry(path); - if (!IS_ERR(ce) && !cache_entry_expired(ce)) { - up_read(&htable_rw_lock); - return 0; - } + if (!IS_ERR(ce) && !cache_entry_expired(ce)) + return ce; + /* * Unlock shared access as we don't want to hold any locks while getting * a new referral. The @ses used for performing the I/O could be @@ -797,8 +801,10 @@ static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, cons * Request a new DFS referral in order to create or update a cache entry. */ rc = get_dfs_referral(xid, ses, path, &refs, &numrefs); - if (rc) + if (rc) { + ce = ERR_PTR(rc); goto out; + } dump_refs(refs, numrefs); @@ -806,16 +812,24 @@ static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, cons /* Re-check as another task might have it added or refreshed already */ ce = lookup_cache_entry(path); if (!IS_ERR(ce)) { - if (cache_entry_expired(ce)) + if (cache_entry_expired(ce)) { rc = update_cache_entry_locked(ce, refs, numrefs); + if (rc) + ce = ERR_PTR(rc); + } } else { - rc = add_cache_entry_locked(refs, numrefs); + ce = add_cache_entry_locked(refs, numrefs); } - up_write(&htable_rw_lock); + if (IS_ERR(ce)) { + up_write(&htable_rw_lock); + goto out; + } + + downgrade_write(&htable_rw_lock); out: free_dfs_info_array(refs, numrefs); - return rc; + return ce; } /* @@ -935,15 +949,8 @@ int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nl if (IS_ERR(npath)) return PTR_ERR(npath); - rc = cache_refresh_path(xid, ses, npath); - if (rc) - goto out_free_path; - - down_read(&htable_rw_lock); - - ce = lookup_cache_entry(npath); + ce = cache_refresh_path(xid, ses, npath); if (IS_ERR(ce)) { - up_read(&htable_rw_lock); rc = PTR_ERR(ce); goto out_free_path; } @@ -1039,10 +1046,13 @@ int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses, cifs_dbg(FYI, "%s: update target hint - path: %s\n", __func__, npath); - rc = cache_refresh_path(xid, ses, npath); - if (rc) + ce = cache_refresh_path(xid, ses, npath); + if (IS_ERR(ce)) { + rc = PTR_ERR(ce); goto out_free_path; + } + up_read(&htable_rw_lock); down_write(&htable_rw_lock); ce = lookup_cache_entry(npath); From patchwork Tue Jan 17 22:00:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paulo Alcantara X-Patchwork-Id: 1727787 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=cjr.nz header.i=@cjr.nz header.a=rsa-sha256 header.s=dkim header.b=Io5Z1E3d; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by legolas.ozlabs.org (Postfix) with ESMTP id 4NxNgR5C8zz23gM for ; Wed, 18 Jan 2023 09:22:43 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229514AbjAQWWj (ORCPT ); Tue, 17 Jan 2023 17:22:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230125AbjAQWVL (ORCPT ); Tue, 17 Jan 2023 17:21:11 -0500 Received: from mx.cjr.nz (mx.cjr.nz [51.158.111.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A4FA61891 for ; Tue, 17 Jan 2023 14:00:58 -0800 (PST) Received: from authenticated-user (mx.cjr.nz [51.158.111.142]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pc) by mx.cjr.nz (Postfix) with ESMTPSA id 248A781774; Tue, 17 Jan 2023 22:00:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cjr.nz; s=dkim; t=1673992857; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RoLT6FGBevRDFW6c/3gZKJ10adla0KKHsK8YClygrKI=; b=Io5Z1E3dPgg7aVvdUJJqEdRevMRqhGZ/Gs9NcYrng5W/R6SXFQm3y4x4jJ0NPKpEyppmL+ zUSUp/louDeAhqoNAvzol+rDWkcwzMKrjP4QqO+OBdKZqDH5JdOJJjLrV3jxKXI9eEBpd7 SOnd6dagnIuq4topg/gzO6jE5ZzfrJYqRINtXB32ZIEDDNztPOppK4X5ySPMAZRkQBtJu1 2C8Rp9YrS2fBAN4Hw46iK9y8Z/qqkt0tvL/qkN96O6rAsxImpWnZq9L9to6ME8ALXWw+h0 uEunjr8oG12khXKpqKuCIeMen4HnntD4r5QBESpRipqr1EmkGxuqcGymzFtXXQ== From: Paulo Alcantara To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org, aurelien.aptel@gmail.com, Paulo Alcantara Subject: [PATCH v2 3/5] cifs: don't take exclusive lock for updating target hints Date: Tue, 17 Jan 2023 19:00:39 -0300 Message-Id: <20230117220041.15905-4-pc@cjr.nz> In-Reply-To: <20230117220041.15905-1-pc@cjr.nz> References: <20230117000952.9965-1-pc@cjr.nz> <20230117220041.15905-1-pc@cjr.nz> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Avoid contention while updating dfs target hints. This should be perfectly fine to update them under shared locks. Signed-off-by: Paulo Alcantara (SUSE) --- fs/cifs/dfs_cache.c | 47 +++++++++++++++++++-------------------------- 1 file changed, 20 insertions(+), 27 deletions(-) diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index 755a00c4cba1..19847f9114ba 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -269,7 +269,7 @@ static int dfscache_proc_show(struct seq_file *m, void *v) list_for_each_entry(t, &ce->tlist, list) { seq_printf(m, " %s%s\n", t->name, - ce->tgthint == t ? " (target hint)" : ""); + READ_ONCE(ce->tgthint) == t ? " (target hint)" : ""); } } } @@ -321,7 +321,7 @@ static inline void dump_tgts(const struct cache_entry *ce) cifs_dbg(FYI, "target list:\n"); list_for_each_entry(t, &ce->tlist, list) { cifs_dbg(FYI, " %s%s\n", t->name, - ce->tgthint == t ? " (target hint)" : ""); + READ_ONCE(ce->tgthint) == t ? " (target hint)" : ""); } } @@ -427,7 +427,7 @@ static int cache_entry_hash(const void *data, int size, unsigned int *hash) /* Return target hint of a DFS cache entry */ static inline char *get_tgt_name(const struct cache_entry *ce) { - struct cache_dfs_tgt *t = ce->tgthint; + struct cache_dfs_tgt *t = READ_ONCE(ce->tgthint); return t ? t->name : ERR_PTR(-ENOENT); } @@ -470,6 +470,7 @@ static struct cache_dfs_tgt *alloc_target(const char *name, int path_consumed) static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs, struct cache_entry *ce, const char *tgthint) { + struct cache_dfs_tgt *target; int i; ce->ttl = max_t(int, refs[0].ttl, CACHE_MIN_TTL); @@ -496,8 +497,9 @@ static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs, ce->numtgts++; } - ce->tgthint = list_first_entry_or_null(&ce->tlist, - struct cache_dfs_tgt, list); + target = list_first_entry_or_null(&ce->tlist, struct cache_dfs_tgt, + list); + WRITE_ONCE(ce->tgthint, target); return 0; } @@ -712,14 +714,15 @@ void dfs_cache_destroy(void) static int update_cache_entry_locked(struct cache_entry *ce, const struct dfs_info3_param *refs, int numrefs) { + struct cache_dfs_tgt *target; + char *th = NULL; int rc; - char *s, *th = NULL; WARN_ON(!rwsem_is_locked(&htable_rw_lock)); - if (ce->tgthint) { - s = ce->tgthint->name; - th = kstrdup(s, GFP_ATOMIC); + target = READ_ONCE(ce->tgthint); + if (target) { + th = kstrdup(target->name, GFP_ATOMIC); if (!th) return -ENOMEM; } @@ -896,7 +899,7 @@ static int get_targets(struct cache_entry *ce, struct dfs_cache_tgt_list *tl) } it->it_path_consumed = t->path_consumed; - if (ce->tgthint == t) + if (READ_ONCE(ce->tgthint) == t) list_add(&it->it_list, head); else list_add_tail(&it->it_list, head); @@ -1052,23 +1055,14 @@ int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses, goto out_free_path; } - up_read(&htable_rw_lock); - down_write(&htable_rw_lock); - - ce = lookup_cache_entry(npath); - if (IS_ERR(ce)) { - rc = PTR_ERR(ce); - goto out_unlock; - } - - t = ce->tgthint; + t = READ_ONCE(ce->tgthint); if (likely(!strcasecmp(it->it_name, t->name))) goto out_unlock; list_for_each_entry(t, &ce->tlist, list) { if (!strcasecmp(t->name, it->it_name)) { - ce->tgthint = t; + WRITE_ONCE(ce->tgthint, t); cifs_dbg(FYI, "%s: new target hint: %s\n", __func__, it->it_name); break; @@ -1076,7 +1070,7 @@ int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses, } out_unlock: - up_write(&htable_rw_lock); + up_read(&htable_rw_lock); out_free_path: kfree(npath); return rc; @@ -1106,21 +1100,20 @@ void dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt cifs_dbg(FYI, "%s: path: %s\n", __func__, path); - if (!down_write_trylock(&htable_rw_lock)) - return; + down_read(&htable_rw_lock); ce = lookup_cache_entry(path); if (IS_ERR(ce)) goto out_unlock; - t = ce->tgthint; + t = READ_ONCE(ce->tgthint); if (unlikely(!strcasecmp(it->it_name, t->name))) goto out_unlock; list_for_each_entry(t, &ce->tlist, list) { if (!strcasecmp(t->name, it->it_name)) { - ce->tgthint = t; + WRITE_ONCE(ce->tgthint, t); cifs_dbg(FYI, "%s: new target hint: %s\n", __func__, it->it_name); break; @@ -1128,7 +1121,7 @@ void dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt } out_unlock: - up_write(&htable_rw_lock); + up_read(&htable_rw_lock); } /** From patchwork Tue Jan 17 22:00:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paulo Alcantara X-Patchwork-Id: 1727791 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=cjr.nz header.i=@cjr.nz header.a=rsa-sha256 header.s=dkim header.b=zSiL5iIh; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by legolas.ozlabs.org (Postfix) with ESMTP id 4NxNhn0FWlz23gM for ; Wed, 18 Jan 2023 09:23:53 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229574AbjAQWXo (ORCPT ); Tue, 17 Jan 2023 17:23:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230161AbjAQWVb (ORCPT ); Tue, 17 Jan 2023 17:21:31 -0500 Received: from mx.cjr.nz (mx.cjr.nz [51.158.111.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26585618BD for ; Tue, 17 Jan 2023 14:01:00 -0800 (PST) Received: from authenticated-user (mx.cjr.nz [51.158.111.142]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pc) by mx.cjr.nz (Postfix) with ESMTPSA id 1F176817BD; Tue, 17 Jan 2023 22:00:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cjr.nz; s=dkim; t=1673992859; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XOpA3ZYf60cELahR+jMHbKwjUsjzrfMZLDtC+F+NupM=; b=zSiL5iIhx2uSJaRsOSjy2se6aCXC/f9RPvEBBrZtktxjUgjMNeXBwymU7ZSL4wHCSQj+S/ Mt305BMgFcCGfd/u6NE9g5w/rJ9cPxi1y687CGHkUiE47h+lwvu7X2xnhV8oCXedO6KVRx fYNa7gqwcPneTnZDijAXjXf3WZ9zQV3Vt9clMG/xo72gJYp6luFKx4coFfMAFtvpikMOaw rhPHD9KusDGusWJVHhAAp2GspA6lxHD1bF1W0j6kxI5y+Q+chdUBU6LRPnd3ikjjHsOjYj 7sw2kppJphuBgNFkfM2Y3qWx1jFx2Y4QQgLGbB8tHb28QNNpLFmII7ZfEDr8bw== From: Paulo Alcantara To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org, aurelien.aptel@gmail.com, Paulo Alcantara Subject: [PATCH v2 4/5] cifs: remove duplicate code in __refresh_tcon() Date: Tue, 17 Jan 2023 19:00:40 -0300 Message-Id: <20230117220041.15905-5-pc@cjr.nz> In-Reply-To: <20230117220041.15905-1-pc@cjr.nz> References: <20230117000952.9965-1-pc@cjr.nz> <20230117220041.15905-1-pc@cjr.nz> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org The logic for creating or updating a cache entry in __refresh_tcon() could be simply done with cache_refresh_path(), so use it instead. Signed-off-by: Paulo Alcantara (SUSE) --- fs/cifs/dfs_cache.c | 69 +++++++++++++++++++++------------------------ 1 file changed, 32 insertions(+), 37 deletions(-) diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index 19847f9114ba..58d11be9d020 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -776,7 +776,8 @@ static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses, const */ static struct cache_entry *cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, - const char *path) + const char *path, + bool force_refresh) { struct dfs_info3_param *refs = NULL; struct cache_entry *ce; @@ -788,7 +789,7 @@ static struct cache_entry *cache_refresh_path(const unsigned int xid, down_read(&htable_rw_lock); ce = lookup_cache_entry(path); - if (!IS_ERR(ce) && !cache_entry_expired(ce)) + if (!IS_ERR(ce) && !force_refresh && !cache_entry_expired(ce)) return ce; /* @@ -800,7 +801,8 @@ static struct cache_entry *cache_refresh_path(const unsigned int xid, up_read(&htable_rw_lock); /* - * Either the entry was not found, or it is expired. + * Either the entry was not found, or it is expired, or it is a forced + * refresh. * Request a new DFS referral in order to create or update a cache entry. */ rc = get_dfs_referral(xid, ses, path, &refs, &numrefs); @@ -815,7 +817,7 @@ static struct cache_entry *cache_refresh_path(const unsigned int xid, /* Re-check as another task might have it added or refreshed already */ ce = lookup_cache_entry(path); if (!IS_ERR(ce)) { - if (cache_entry_expired(ce)) { + if (force_refresh || cache_entry_expired(ce)) { rc = update_cache_entry_locked(ce, refs, numrefs); if (rc) ce = ERR_PTR(rc); @@ -952,7 +954,7 @@ int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nl if (IS_ERR(npath)) return PTR_ERR(npath); - ce = cache_refresh_path(xid, ses, npath); + ce = cache_refresh_path(xid, ses, npath, false); if (IS_ERR(ce)) { rc = PTR_ERR(ce); goto out_free_path; @@ -1049,7 +1051,7 @@ int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses, cifs_dbg(FYI, "%s: update target hint - path: %s\n", __func__, npath); - ce = cache_refresh_path(xid, ses, npath); + ce = cache_refresh_path(xid, ses, npath, false); if (IS_ERR(ce)) { rc = PTR_ERR(ce); goto out_free_path; @@ -1327,35 +1329,37 @@ static bool target_share_equal(struct TCP_Server_Info *server, const char *s1, c * Mark dfs tcon for reconnecting when the currently connected tcon does not match any of the new * target shares in @refs. */ -static void mark_for_reconnect_if_needed(struct cifs_tcon *tcon, struct dfs_cache_tgt_list *tl, - const struct dfs_info3_param *refs, int numrefs) +static void mark_for_reconnect_if_needed(struct TCP_Server_Info *server, + struct dfs_cache_tgt_list *old_tl, + struct dfs_cache_tgt_list *new_tl) { - struct dfs_cache_tgt_iterator *it; - int i; + struct dfs_cache_tgt_iterator *oit, *nit; - for (it = dfs_cache_get_tgt_iterator(tl); it; it = dfs_cache_get_next_tgt(tl, it)) { - for (i = 0; i < numrefs; i++) { - if (target_share_equal(tcon->ses->server, dfs_cache_get_tgt_name(it), - refs[i].node_name)) + for (oit = dfs_cache_get_tgt_iterator(old_tl); oit; + oit = dfs_cache_get_next_tgt(old_tl, oit)) { + for (nit = dfs_cache_get_tgt_iterator(new_tl); nit; + nit = dfs_cache_get_next_tgt(new_tl, nit)) { + if (target_share_equal(server, + dfs_cache_get_tgt_name(oit), + dfs_cache_get_tgt_name(nit))) return; } } cifs_dbg(FYI, "%s: no cached or matched targets. mark dfs share for reconnect.\n", __func__); - cifs_signal_cifsd_for_reconnect(tcon->ses->server, true); + cifs_signal_cifsd_for_reconnect(server, true); } /* Refresh dfs referral of tcon and mark it for reconnect if needed */ static int __refresh_tcon(const char *path, struct cifs_tcon *tcon, bool force_refresh) { - struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl); + struct dfs_cache_tgt_list old_tl = DFS_CACHE_TGT_LIST_INIT(old_tl); + struct dfs_cache_tgt_list new_tl = DFS_CACHE_TGT_LIST_INIT(new_tl); struct cifs_ses *ses = CIFS_DFS_ROOT_SES(tcon->ses); struct cifs_tcon *ipc = ses->tcon_ipc; - struct dfs_info3_param *refs = NULL; bool needs_refresh = false; struct cache_entry *ce; unsigned int xid; - int numrefs = 0; int rc = 0; xid = get_xid(); @@ -1364,9 +1368,8 @@ static int __refresh_tcon(const char *path, struct cifs_tcon *tcon, bool force_r ce = lookup_cache_entry(path); needs_refresh = force_refresh || IS_ERR(ce) || cache_entry_expired(ce); if (!IS_ERR(ce)) { - rc = get_targets(ce, &tl); - if (rc) - cifs_dbg(FYI, "%s: could not get dfs targets: %d\n", __func__, rc); + rc = get_targets(ce, &old_tl); + cifs_dbg(FYI, "%s: get_targets: %d\n", __func__, rc); } up_read(&htable_rw_lock); @@ -1383,26 +1386,18 @@ static int __refresh_tcon(const char *path, struct cifs_tcon *tcon, bool force_r } spin_unlock(&ipc->tc_lock); - rc = get_dfs_referral(xid, ses, path, &refs, &numrefs); - if (!rc) { - /* Create or update a cache entry with the new referral */ - dump_refs(refs, numrefs); - - down_write(&htable_rw_lock); - ce = lookup_cache_entry(path); - if (IS_ERR(ce)) - add_cache_entry_locked(refs, numrefs); - else if (force_refresh || cache_entry_expired(ce)) - update_cache_entry_locked(ce, refs, numrefs); - up_write(&htable_rw_lock); - - mark_for_reconnect_if_needed(tcon, &tl, refs, numrefs); + ce = cache_refresh_path(xid, ses, path, true); + if (!IS_ERR(ce)) { + rc = get_targets(ce, &new_tl); + up_read(&htable_rw_lock); + cifs_dbg(FYI, "%s: get_targets: %d\n", __func__, rc); + mark_for_reconnect_if_needed(tcon->ses->server, &old_tl, &new_tl); } out: free_xid(xid); - dfs_cache_free_tgts(&tl); - free_dfs_info_array(refs, numrefs); + dfs_cache_free_tgts(&old_tl); + dfs_cache_free_tgts(&new_tl); return rc; } From patchwork Tue Jan 17 22:00:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paulo Alcantara X-Patchwork-Id: 1727789 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=cjr.nz header.i=@cjr.nz header.a=rsa-sha256 header.s=dkim header.b=lSj6ctOt; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by legolas.ozlabs.org (Postfix) with ESMTP id 4NxNgS5sSHz23h4 for ; Wed, 18 Jan 2023 09:22:44 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230029AbjAQWWl (ORCPT ); Tue, 17 Jan 2023 17:22:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230138AbjAQWVW (ORCPT ); Tue, 17 Jan 2023 17:21:22 -0500 Received: from mx.cjr.nz (mx.cjr.nz [51.158.111.142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26089618B6 for ; Tue, 17 Jan 2023 14:01:05 -0800 (PST) Received: from authenticated-user (mx.cjr.nz [51.158.111.142]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pc) by mx.cjr.nz (Postfix) with ESMTPSA id 0F265817D4; Tue, 17 Jan 2023 22:00:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cjr.nz; s=dkim; t=1673992861; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ic9e4+ceYYlZYr/hlG2Eu49hTci5KP8LXbEt0apG5ec=; b=lSj6ctOtE0C5DVNdZvPnqgNlZdQ+kQk/jihLkiFX9cc1JW5NVQgb9n0IrZcIP1TOmApud5 39nwJqa5bmXeoZfC6wMi6JbJLuLXtozxmwrlPJqUh1LhzZpWUW4KPZFnIKqadaFELyjMPD QUXgw5k7mTPJtRkJsERdSz5rzlWHgbx/aVdURBP+oQL60aOIrIaWXNITDclpCloF72vHGY 7FYPa+JCrKb5H+P9cj+yMom36S6V7k92dWHOvjSlANAXyI+4B4asmpyetsWM2i6JHw6Tnd ILIDpwdTRulEaZPTBC9OXvhKnQUCeoungd6hGiKe0a2z9KHIaH7K70G91gfN4g== From: Paulo Alcantara To: smfrench@gmail.com Cc: linux-cifs@vger.kernel.org, aurelien.aptel@gmail.com, Paulo Alcantara Subject: [PATCH v2 5/5] cifs: handle cache lookup errors different than -ENOENT Date: Tue, 17 Jan 2023 19:00:41 -0300 Message-Id: <20230117220041.15905-6-pc@cjr.nz> In-Reply-To: <20230117220041.15905-1-pc@cjr.nz> References: <20230117000952.9965-1-pc@cjr.nz> <20230117220041.15905-1-pc@cjr.nz> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org lookup_cache_entry() might return an error different than -ENOENT (e.g. from ->char2uni), so handle those as well in cache_refresh_path(). Signed-off-by: Paulo Alcantara (SUSE) --- fs/cifs/dfs_cache.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index 58d11be9d020..308101d90006 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -644,7 +644,9 @@ static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int h * * Use whole path components in the match. Must be called with htable_rw_lock held. * + * Return cached entry if successful. * Return ERR_PTR(-ENOENT) if the entry is not found. + * Return error ptr otherwise. */ static struct cache_entry *lookup_cache_entry(const char *path) { @@ -789,8 +791,13 @@ static struct cache_entry *cache_refresh_path(const unsigned int xid, down_read(&htable_rw_lock); ce = lookup_cache_entry(path); - if (!IS_ERR(ce) && !force_refresh && !cache_entry_expired(ce)) + if (!IS_ERR(ce)) { + if (!force_refresh && !cache_entry_expired(ce)) + return ce; + } else if (PTR_ERR(ce) != -ENOENT) { + up_read(&htable_rw_lock); return ce; + } /* * Unlock shared access as we don't want to hold any locks while getting @@ -822,7 +829,7 @@ static struct cache_entry *cache_refresh_path(const unsigned int xid, if (rc) ce = ERR_PTR(rc); } - } else { + } else if (PTR_ERR(ce) == -ENOENT) { ce = add_cache_entry_locked(refs, numrefs); }