From patchwork Thu Dec 16 16:16:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12681785 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A6B0C433FE for ; Thu, 16 Dec 2021 16:17:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236081AbhLPQRU (ORCPT ); Thu, 16 Dec 2021 11:17:20 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:38582 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239522AbhLPQRE (ORCPT ); Thu, 16 Dec 2021 11:17:04 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639671423; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KLMNgmVAoRi/NMJEjfBUwrT1pdlHf9vhqCbKzHWcqWI=; b=Ji2fp4Irv/rLiCO7f2G2oAE5xNLj/27b8dwbJnWzKpTm5Zyg6ZVIm5+mxhn8mJ0Dg5HWrr eEsHHk9co6vXhvitAHpRopanDPa2F8h08L17rePpOHMnZouf003Q6/KhLpiQf/uc86P4i0 YnHJEJ1ii2dQdazZRe554fnTqyT9sxQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-625-EMw59qA4OiC-vGYIqS6Tfw-1; Thu, 16 Dec 2021 11:16:47 -0500 X-MC-Unique: EMw59qA4OiC-vGYIqS6Tfw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BE065100D844; Thu, 16 Dec 2021 16:16:44 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.122]) by smtp.corp.redhat.com (Postfix) with ESMTP id 59933795AD; Thu, 16 Dec 2021 16:16:41 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH v3 37/68] cachefiles: Provide a function to check how much space there is From: David Howells To: linux-cachefs@redhat.com Cc: dhowells@redhat.com, Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet , Jeff Layton , Matthew Wilcox , Alexander Viro , Omar Sandoval , JeffleXu , Linus Torvalds , linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 16 Dec 2021 16:16:40 +0000 Message-ID: <163967140058.1823006.7781243664702837128.stgit@warthog.procyon.org.uk> In-Reply-To: <163967073889.1823006.12237147297060239168.stgit@warthog.procyon.org.uk> References: <163967073889.1823006.12237147297060239168.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Provide a function to check how much space there is. This also flips the state on the cache and will signal the daemon to inform it of the change and to ask it to do some culling if necessary. We will also need to subtract the amount of data currently being written to the cache (cache->b_writing) from the amount of available space to avoid hitting ENOSPC accidentally. Signed-off-by: David Howells cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819629322.215744.13457425294680841213.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906930100.143852.1681026700865762069.stgit@warthog.procyon.org.uk/ # v2 --- fs/cachefiles/Makefile | 1 fs/cachefiles/cache.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++ fs/cachefiles/daemon.c | 2 - fs/cachefiles/internal.h | 7 +++ 4 files changed, 112 insertions(+), 1 deletion(-) create mode 100644 fs/cachefiles/cache.c diff --git a/fs/cachefiles/Makefile b/fs/cachefiles/Makefile index f008524bb78f..463e3d608b75 100644 --- a/fs/cachefiles/Makefile +++ b/fs/cachefiles/Makefile @@ -4,6 +4,7 @@ # cachefiles-y := \ + cache.o \ daemon.o \ main.o \ security.o diff --git a/fs/cachefiles/cache.c b/fs/cachefiles/cache.c new file mode 100644 index 000000000000..73636f89eefa --- /dev/null +++ b/fs/cachefiles/cache.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Manage high-level VFS aspects of a cache. + * + * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include "internal.h" + +/* + * See if we have space for a number of pages and/or a number of files in the + * cache + */ +int cachefiles_has_space(struct cachefiles_cache *cache, + unsigned fnr, unsigned bnr) +{ + struct kstatfs stats; + u64 b_avail, b_writing; + int ret; + + struct path path = { + .mnt = cache->mnt, + .dentry = cache->mnt->mnt_root, + }; + + //_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u", + // (unsigned long long) cache->frun, + // (unsigned long long) cache->fcull, + // (unsigned long long) cache->fstop, + // (unsigned long long) cache->brun, + // (unsigned long long) cache->bcull, + // (unsigned long long) cache->bstop, + // fnr, bnr); + + /* find out how many pages of blockdev are available */ + memset(&stats, 0, sizeof(stats)); + + ret = vfs_statfs(&path, &stats); + if (ret < 0) { + trace_cachefiles_vfs_error(NULL, d_inode(path.dentry), ret, + cachefiles_trace_statfs_error); + if (ret == -EIO) + cachefiles_io_error(cache, "statfs failed"); + _leave(" = %d", ret); + return ret; + } + + b_avail = stats.f_bavail >> cache->bshift; + b_writing = atomic_long_read(&cache->b_writing); + if (b_avail > b_writing) + b_avail -= b_writing; + else + b_avail = 0; + + //_debug("avail %llu,%llu", + // (unsigned long long)stats.f_ffree, + // (unsigned long long)b_avail); + + /* see if there is sufficient space */ + if (stats.f_ffree > fnr) + stats.f_ffree -= fnr; + else + stats.f_ffree = 0; + + if (b_avail > bnr) + b_avail -= bnr; + else + b_avail = 0; + + ret = -ENOBUFS; + if (stats.f_ffree < cache->fstop || + b_avail < cache->bstop) + goto begin_cull; + + ret = 0; + if (stats.f_ffree < cache->fcull || + b_avail < cache->bcull) + goto begin_cull; + + if (test_bit(CACHEFILES_CULLING, &cache->flags) && + stats.f_ffree >= cache->frun && + b_avail >= cache->brun && + test_and_clear_bit(CACHEFILES_CULLING, &cache->flags) + ) { + _debug("cease culling"); + cachefiles_state_changed(cache); + } + + //_leave(" = 0"); + return 0; + +begin_cull: + if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) { + _debug("### CULL CACHE ###"); + cachefiles_state_changed(cache); + } + + _leave(" = %d", ret); + return ret; +} diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c index 4cfb7c8b37d0..7d4691614cec 100644 --- a/fs/cachefiles/daemon.c +++ b/fs/cachefiles/daemon.c @@ -167,7 +167,7 @@ static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, return 0; /* check how much space the cache has */ - // PLACEHOLDER: Check space + cachefiles_has_space(cache, 0, 0); /* summarise */ f_released = atomic_xchg(&cache->f_released, 0); diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 7fd5429715ea..3783a3e01027 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -39,6 +39,7 @@ struct cachefiles_cache { atomic_t gravecounter; /* graveyard uniquifier */ atomic_t f_released; /* number of objects released lately */ atomic_long_t b_released; /* number of blocks released lately */ + atomic_long_t b_writing; /* Number of blocks being written */ unsigned frun_percent; /* when to stop culling (% files) */ unsigned fcull_percent; /* when to start culling (% files) */ unsigned fstop_percent; /* when to stop allocating (% files) */ @@ -74,6 +75,12 @@ static inline void cachefiles_state_changed(struct cachefiles_cache *cache) wake_up_all(&cache->daemon_pollwq); } +/* + * cache.c + */ +extern int cachefiles_has_space(struct cachefiles_cache *cache, + unsigned fnr, unsigned bnr); + /* * daemon.c */