From patchwork Mon Nov 29 14:31:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 12645015 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 D56CFC4332F for ; Mon, 29 Nov 2021 14:34:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378596AbhK2Ohk (ORCPT ); Mon, 29 Nov 2021 09:37:40 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:55493 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378566AbhK2Off (ORCPT ); Mon, 29 Nov 2021 09:35:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1638196336; 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=KBBNZ+OnXSpjgU3Tn3aeXgtU7JQePtMicZax2+gvBrI=; b=E9Z03MAwJj+fgG9C5JGrSvALa1MIEl8iqifMBlWe9L1Ec+Wi18wNK+whe/Zw+x8WMDFveP 0Mwot+xIvMMNnNXfDTuzGydFfl1/srjH7qZ8dOW/jn1hqRL0r5iU5JHFPgGwuXxBda59vF U5KYP7wIQk79YhAAzIOFixyK0P7us8I= 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-7-RsKyt9oINoaNCMgab2fL2w-1; Mon, 29 Nov 2021 09:32:10 -0500 X-MC-Unique: RsKyt9oINoaNCMgab2fL2w-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 82D93101F02C; Mon, 29 Nov 2021 14:32:06 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.25]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9F58445D64; Mon, 29 Nov 2021 14:31:52 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 39/64] cachefiles: Implement a function to get/create a directory in the cache 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 , 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: Mon, 29 Nov 2021 14:31:51 +0000 Message-ID: <163819631182.215744.3322471539523262619.stgit@warthog.procyon.org.uk> In-Reply-To: <163819575444.215744.318477214576928110.stgit@warthog.procyon.org.uk> References: <163819575444.215744.318477214576928110.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Implement a function to get/create structural directories in the cache. This is used for setting up a cache and creating volume substructures. The directory in memory are marked with the S_KERNEL_FILE inode flag whilst they're in use to tell rmdir to reject attempts to remove them. Signed-off-by: David Howells cc: linux-cachefs@redhat.com --- fs/cachefiles/internal.h | 8 +++ fs/cachefiles/namei.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 146 insertions(+) diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h index 3783a3e01027..65e01ac1da39 100644 --- a/fs/cachefiles/internal.h +++ b/fs/cachefiles/internal.h @@ -125,6 +125,14 @@ static inline int cachefiles_inject_remove_error(void) return cachefiles_error_injection_state & 2 ? -EIO : 0; } +/* + * namei.c + */ +extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, + struct dentry *dir, + const char *name); +extern void cachefiles_put_directory(struct dentry *dir); + /* * security.c */ diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index fef06d2a88ec..25ca41952dab 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -6,6 +6,7 @@ */ #include +#include #include "internal.h" /* @@ -42,3 +43,140 @@ static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object, inode->i_flags &= ~S_KERNEL_FILE; trace_cachefiles_mark_inactive(object, inode); } + +/* + * get a subdirectory + */ +struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache, + struct dentry *dir, + const char *dirname) +{ + struct dentry *subdir; + struct path path; + int ret; + + _enter(",,%s", dirname); + + /* search the current directory for the element name */ + inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); + +retry: + ret = cachefiles_inject_read_error(); + if (ret == 0) + subdir = lookup_one_len(dirname, dir, strlen(dirname)); + else + subdir = ERR_PTR(ret); + if (IS_ERR(subdir)) { + trace_cachefiles_vfs_error(NULL, d_backing_inode(dir), + PTR_ERR(subdir), + cachefiles_trace_lookup_error); + if (PTR_ERR(subdir) == -ENOMEM) + goto nomem_d_alloc; + goto lookup_error; + } + + _debug("subdir -> %pd %s", + subdir, d_backing_inode(subdir) ? "positive" : "negative"); + + /* we need to create the subdir if it doesn't exist yet */ + if (d_is_negative(subdir)) { + ret = cachefiles_has_space(cache, 1, 0); + if (ret < 0) + goto mkdir_error; + + _debug("attempt mkdir"); + + path.mnt = cache->mnt; + path.dentry = dir; + ret = security_path_mkdir(&path, subdir, 0700); + if (ret < 0) + goto mkdir_error; + ret = cachefiles_inject_write_error(); + if (ret == 0) + ret = vfs_mkdir(&init_user_ns, d_inode(dir), subdir, 0700); + if (ret < 0) { + trace_cachefiles_vfs_error(NULL, d_inode(dir), ret, + cachefiles_trace_mkdir_error); + goto mkdir_error; + } + + if (unlikely(d_unhashed(subdir))) { + cachefiles_put_directory(subdir); + goto retry; + } + ASSERT(d_backing_inode(subdir)); + + _debug("mkdir -> %pd{ino=%lu}", + subdir, d_backing_inode(subdir)->i_ino); + } + + /* Tell rmdir() it's not allowed to delete the subdir */ + inode_lock(d_inode(subdir)); + inode_unlock(d_inode(dir)); + + if (!__cachefiles_mark_inode_in_use(NULL, subdir)) + goto mark_error; + + inode_unlock(d_inode(subdir)); + + /* we need to make sure the subdir is a directory */ + ASSERT(d_backing_inode(subdir)); + + if (!d_can_lookup(subdir)) { + pr_err("%s is not a directory\n", dirname); + ret = -EIO; + goto check_error; + } + + ret = -EPERM; + if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) || + !d_backing_inode(subdir)->i_op->lookup || + !d_backing_inode(subdir)->i_op->mkdir || + !d_backing_inode(subdir)->i_op->rename || + !d_backing_inode(subdir)->i_op->rmdir || + !d_backing_inode(subdir)->i_op->unlink) + goto check_error; + + _leave(" = [%lu]", d_backing_inode(subdir)->i_ino); + return subdir; + +check_error: + cachefiles_put_directory(subdir); + _leave(" = %d [check]", ret); + return ERR_PTR(ret); + +mark_error: + inode_unlock(d_inode(subdir)); + dput(subdir); + return ERR_PTR(-EBUSY); + +mkdir_error: + inode_unlock(d_inode(dir)); + dput(subdir); + pr_err("mkdir %s failed with error %d\n", dirname, ret); + return ERR_PTR(ret); + +lookup_error: + inode_unlock(d_inode(dir)); + ret = PTR_ERR(subdir); + pr_err("Lookup %s failed with error %d\n", dirname, ret); + return ERR_PTR(ret); + +nomem_d_alloc: + inode_unlock(d_inode(dir)); + _leave(" = -ENOMEM"); + return ERR_PTR(-ENOMEM); +} + +/* + * Put a subdirectory. + */ +void cachefiles_put_directory(struct dentry *dir) +{ + if (dir) { + inode_lock(dir->d_inode); + __cachefiles_unmark_inode_in_use(NULL, dir); + inode_unlock(dir->d_inode); + dput(dir); + } +}