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[2620:137:e000::1:20]) by mx.google.com with ESMTP id a8-20020a656548000000b0050b508f68d8si4738742pgw.206.2023.04.14.10.29.22; Fri, 14 Apr 2023 10:29:35 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@bytedance.com header.s=google header.b=GwvrOTtJ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=bytedance.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230379AbjDNRYU (ORCPT + 99 others); Fri, 14 Apr 2023 13:24:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230233AbjDNRX4 (ORCPT ); Fri, 14 Apr 2023 13:23:56 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8265902A for ; Fri, 14 Apr 2023 10:23:29 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id my14-20020a17090b4c8e00b0024708e8e2ddso8441003pjb.4 for ; Fri, 14 Apr 2023 10:23:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1681493009; x=1684085009; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ySOXSnP6FL6oSMQRzhqbuOuGsOFMLOtSkAgA+zIYAhs=; b=GwvrOTtJ/qpLMxFnCQ9BNbH6VmRUx6fBicNS3ilywFLg7uhNJHZz/euh0PpduinHca mVzeJETlDXk9MICZ41xp5R4ySy026Ji6VYxLBAELLM6IhUgIbfvKzp1UUQfy9TQI3rAs bDYDGhZlQDqnkkxs2W8GWKCYc3Le1t4guIjxa9WgT4v86RnE/BlnhIKikjdlcAQxwmqZ exQcS4bmfvdRg9CP2O796tHKjkq4+cgfKoChX8biLVopb9T2bjwkclYioHRyD9lMgwEM SEoEICJqmtNABkTdegIgsBEQw3uzB8vrJAl2Zz715GwJE2h23zcUW/HD5TnNeou8K/7G Q7Uw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681493009; x=1684085009; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ySOXSnP6FL6oSMQRzhqbuOuGsOFMLOtSkAgA+zIYAhs=; b=Ak4IotQbHzncAZe+icA2UTXJs0qGlLce5Z8CLLiZxhtiul7mZejRqBY38QL3g7ZeAc VHpWmV8AAlrwY0JKWIZmy7TwTFmtnfkgdA2uTQIyhhx/ZlsjJ+2GWjgZmA/yuNWdN7+3 y6WX1iyCAPsUkoPJL9fXVE/SSJHeOEItfPbSTgGuDemBLnal9xvYdA2iOrS/fcKFid/G cLXVkjyQWwvGTBDbSn4/q+slSXWpv/JQhCsLJkk4wZOEcWp5As8L6lWd7JhrpvUnNaML 2xwKLBQHClt7Hr90k/6+IcgjzLRxTi8iy26sN1znnW/01J/MXGOlFYG1mb2aYXUg03gd 9zEQ== X-Gm-Message-State: AAQBX9dQK3w8nyzZ/kG0gSAUqybgimpj8HMVDs9eq3GUopNobDCjjd+M /QxpbAtanDctwYkYmzd4Rw/cepw8Sv9dLZYKNw5+pg== X-Received: by 2002:a17:90a:460e:b0:23f:7e2e:fe13 with SMTP id w14-20020a17090a460e00b0023f7e2efe13mr6442173pjg.0.1681493009218; Fri, 14 Apr 2023 10:23:29 -0700 (PDT) Received: from localhost.localdomain ([139.177.225.243]) by smtp.gmail.com with ESMTPSA id q12-20020a631f4c000000b0051b8172fa68sm370315pgm.38.2023.04.14.10.23.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Apr 2023 10:23:28 -0700 (PDT) From: Jia Zhu To: dhowells@redhat.com, linux-cachefs@redhat.com Cc: linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, jefflexu@linux.alibaba.com, hsiangkao@linux.alibaba.com, Jia Zhu Subject: [PATCH V6 3/5] cachefiles: resend an open request if the read request's object is closed Date: Sat, 15 Apr 2023 01:22:37 +0800 Message-Id: <20230414172239.33743-4-zhujia.zj@bytedance.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) In-Reply-To: <20230414172239.33743-1-zhujia.zj@bytedance.com> References: <20230414172239.33743-1-zhujia.zj@bytedance.com> 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,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE 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-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1763173598049994438?= X-GMAIL-MSGID: =?utf-8?q?1763173598049994438?= When an anonymous fd is closed by user daemon, if there is a new read request for this file comes up, the anonymous fd should be re-opened to handle that read request rather than fail it directly. 1. Introduce reopening state for objects that are closed but have inflight/subsequent read requests. 2. No longer flush READ requests but only CLOSE requests when anonymous fd is closed. 3. Enqueue the reopen work to workqueue, thus user daemon could get rid of daemon_read context and handle that request smoothly. Otherwise, the user daemon will send a reopen request and wait for itself to process the request. Signed-off-by: Jia Zhu --- fs/cachefiles/internal.h | 3 ++ fs/cachefiles/ondemand.c | 98 ++++++++++++++++++++++++++++------------ 2 files changed, 72 insertions(+), 29 deletions(-) diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index b0fe76964bc0d..b9a90f1a0c015 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -47,9 +47,11 @@ struct cachefiles_volume { enum cachefiles_object_state { CACHEFILES_ONDEMAND_OBJSTATE_CLOSE, /* Anonymous fd closed by daemon or initial state */ CACHEFILES_ONDEMAND_OBJSTATE_OPEN, /* Anonymous fd associated with object is available */ + CACHEFILES_ONDEMAND_OBJSTATE_REOPENING, /* Object that was closed and is being reopened. */ }; struct cachefiles_ondemand_info { + struct work_struct ondemand_work; int ondemand_id; enum cachefiles_object_state state; struct cachefiles_object *object; @@ -326,6 +328,7 @@ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \ CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN); CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE); +CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING); #else static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c index deb7e3007aa1d..8e130de952f7d 100644 --- a/fs/cachefiles/ondemand.c +++ b/fs/cachefiles/ondemand.c @@ -18,14 +18,10 @@ static int cachefiles_ondemand_fd_release(struct inode *inode, info->ondemand_id = CACHEFILES_ONDEMAND_ID_CLOSED; cachefiles_ondemand_set_object_close(object); - /* - * Flush all pending READ requests since their completion depends on - * anon_fd. - */ - xas_for_each(&xas, req, ULONG_MAX) { + /* Only flush CACHEFILES_REQ_NEW marked req to avoid race with daemon_read */ + xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) { if (req->msg.object_id == object_id && - req->msg.opcode == CACHEFILES_OP_READ) { - req->error = -EIO; + req->msg.opcode == CACHEFILES_OP_CLOSE) { complete(&req->done); xas_store(&xas, NULL); } @@ -179,6 +175,7 @@ int cachefiles_ondemand_copen(struct cachefiles_cache *cache, char *args) trace_cachefiles_ondemand_copen(req->object, id, size); cachefiles_ondemand_set_object_open(req->object); + wake_up_all(&cache->daemon_pollwq); out: complete(&req->done); @@ -222,7 +219,6 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) load = (void *)req->msg.data; load->fd = fd; - req->msg.object_id = object_id; object->ondemand->ondemand_id = object_id; cachefiles_get_unbind_pincount(cache); @@ -238,6 +234,43 @@ static int cachefiles_ondemand_get_fd(struct cachefiles_req *req) return ret; } +static void ondemand_object_worker(struct work_struct *work) +{ + struct cachefiles_ondemand_info *info = + container_of(work, struct cachefiles_ondemand_info, ondemand_work); + + cachefiles_ondemand_init_object(info->object); +} + +/* + * If there are any inflight or subsequent READ requests on the + * closed object, reopen it. + * Skip read requests whose related object is reopening. + */ +static struct cachefiles_req *cachefiles_ondemand_select_req(struct xa_state *xas, + unsigned long xa_max) +{ + struct cachefiles_req *req; + struct cachefiles_object *object; + struct cachefiles_ondemand_info *info; + + xas_for_each_marked(xas, req, xa_max, CACHEFILES_REQ_NEW) { + if (req->msg.opcode != CACHEFILES_OP_READ) + return req; + object = req->object; + info = object->ondemand; + if (cachefiles_ondemand_object_is_close(object)) { + cachefiles_ondemand_set_object_reopening(object); + queue_work(fscache_wq, &info->ondemand_work); + continue; + } + if (cachefiles_ondemand_object_is_reopening(object)) + continue; + return req; + } + return NULL; +} + ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, char __user *_buffer, size_t buflen) { @@ -248,16 +281,16 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, int ret = 0; XA_STATE(xas, &cache->reqs, cache->req_id_next); + xa_lock(&cache->reqs); /* * Cyclically search for a request that has not ever been processed, * to prevent requests from being processed repeatedly, and make * request distribution fair. */ - xa_lock(&cache->reqs); - req = xas_find_marked(&xas, UINT_MAX, CACHEFILES_REQ_NEW); + req = cachefiles_ondemand_select_req(&xas, ULONG_MAX); if (!req && cache->req_id_next > 0) { xas_set(&xas, 0); - req = xas_find_marked(&xas, cache->req_id_next - 1, CACHEFILES_REQ_NEW); + req = cachefiles_ondemand_select_req(&xas, cache->req_id_next - 1); } if (!req) { xa_unlock(&cache->reqs); @@ -277,14 +310,18 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache, xa_unlock(&cache->reqs); id = xas.xa_index; - msg->msg_id = id; if (msg->opcode == CACHEFILES_OP_OPEN) { ret = cachefiles_ondemand_get_fd(req); - if (ret) + if (ret) { + cachefiles_ondemand_set_object_close(req->object); goto error; + } } + msg->msg_id = id; + msg->object_id = req->object->ondemand->ondemand_id; + if (copy_to_user(_buffer, msg, n) != 0) { ret = -EFAULT; goto err_put_fd; @@ -317,19 +354,23 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, void *private) { struct cachefiles_cache *cache = object->volume->cache; - struct cachefiles_req *req; + struct cachefiles_req *req = NULL; XA_STATE(xas, &cache->reqs, 0); int ret; if (!test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags)) return 0; - if (test_bit(CACHEFILES_DEAD, &cache->flags)) - return -EIO; + if (test_bit(CACHEFILES_DEAD, &cache->flags)) { + ret = -EIO; + goto out; + } req = kzalloc(sizeof(*req) + data_len, GFP_KERNEL); - if (!req) - return -ENOMEM; + if (!req) { + ret = -ENOMEM; + goto out; + } req->object = object; init_completion(&req->done); @@ -367,7 +408,7 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, /* coupled with the barrier in cachefiles_flush_reqs() */ smp_mb(); - if (opcode != CACHEFILES_OP_OPEN && + if (opcode == CACHEFILES_OP_CLOSE && !cachefiles_ondemand_object_is_open(object)) { WARN_ON_ONCE(object->ondemand->ondemand_id == 0); xas_unlock(&xas); @@ -392,7 +433,15 @@ static int cachefiles_ondemand_send_req(struct cachefiles_object *object, wake_up_all(&cache->daemon_pollwq); wait_for_completion(&req->done); ret = req->error; + kfree(req); + return ret; out: + /* Reset the object to close state in error handling path. + * If error occurs after creating the anonymous fd, + * cachefiles_ondemand_fd_release() will set object to close. + */ + if (opcode == CACHEFILES_OP_OPEN) + cachefiles_ondemand_set_object_close(object); kfree(req); return ret; } @@ -439,7 +488,6 @@ static int cachefiles_ondemand_init_close_req(struct cachefiles_req *req, if (!cachefiles_ondemand_object_is_open(object)) return -ENOENT; - req->msg.object_id = object->ondemand->ondemand_id; trace_cachefiles_ondemand_close(object, &req->msg); return 0; } @@ -455,16 +503,7 @@ static int cachefiles_ondemand_init_read_req(struct cachefiles_req *req, struct cachefiles_object *object = req->object; struct cachefiles_read *load = (void *)req->msg.data; struct cachefiles_read_ctx *read_ctx = private; - int object_id = object->ondemand->ondemand_id; - - /* Stop enqueuing requests when daemon has closed anon_fd. */ - if (!cachefiles_ondemand_object_is_open(object)) { - WARN_ON_ONCE(object_id == 0); - pr_info_once("READ: anonymous fd closed prematurely.\n"); - return -EIO; - } - req->msg.object_id = object_id; load->off = read_ctx->off; load->len = read_ctx->len; trace_cachefiles_ondemand_read(object, &req->msg, load); @@ -513,6 +552,7 @@ int cachefiles_ondemand_init_obj_info(struct cachefiles_object *object, return -ENOMEM; object->ondemand->object = object; + INIT_WORK(&object->ondemand->ondemand_work, ondemand_object_worker); return 0; }