From patchwork Mon Jul 13 17:28:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Down X-Patchwork-Id: 11660813 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6385213B4 for ; Mon, 13 Jul 2020 17:28:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 45C2F206F5 for ; Mon, 13 Jul 2020 17:28:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="JNL0TMcu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730434AbgGMR23 (ORCPT ); Mon, 13 Jul 2020 13:28:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730380AbgGMR22 (ORCPT ); Mon, 13 Jul 2020 13:28:28 -0400 Received: from mail-ej1-x641.google.com (mail-ej1-x641.google.com [IPv6:2a00:1450:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3992C061755 for ; Mon, 13 Jul 2020 10:28:28 -0700 (PDT) Received: by mail-ej1-x641.google.com with SMTP id l12so18146515ejn.10 for ; Mon, 13 Jul 2020 10:28:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=gueaV2wIJr/nXnGZ1QG9gTmS9FKOEq1Ps1eBHo/++Xs=; b=JNL0TMcuk4UDCLWif2LH8K842tkj63LpxOOpwvVsoreKcWtI8kX5Y3Y/pjW2LvJde9 19Cl6JyvqLxD+0Eo7EdZOr/HsF+dSEsK3u3E+c3VP5iEB6cOGvfo9Zc3ONZrSM0AUpNC PJpdXxhiiGJpjkirDfQB3m5/MnP/bizl37Tog= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=gueaV2wIJr/nXnGZ1QG9gTmS9FKOEq1Ps1eBHo/++Xs=; b=IPIPYkOU8Uxkmg+IEbe43VMPNsxKtZdhRl8gNCUWDDgrdJI4UIS9EoK4vyBwc3YQGS JizMZ/p++++8tsyE6igoQXC3V3KUiNTv2G+/iUOr3WmoWL90Hxq9cU45KMS/5YifWs0D mrOTXnFuDeLXlKMA9/uZGHYnezNOybFejXoaFiMf/nr5hT9+KuxIC5RmleMV7vPokLPu a3ciOnWq6B55yfnVuydXnz1MQqBx66OUGS5hG773fZcsBfDsKmhg8FL5q6UQMZq1lL3N ezqYPYmcojXKdqW1BqNWosI5LdhvW/UOHtMyrItq0UyYnHIdW4v5xezjhqVxD0OjM7ML KJ5w== X-Gm-Message-State: AOAM530vmIB1FMvw4/5+AkHeeI8XB6vslaL9b6jwz8Wpo6Qm6aZyL4CX jLorYcK2pNcLprb2dQMOw4Glpg== X-Google-Smtp-Source: ABdhPJzGceRKr7Ho3EG48gwAk3TwXvpo8QcnBYzSqYibywqA+ihCr25RuKdCWVYt5p/2XCK8HAuGZw== X-Received: by 2002:a17:906:3e13:: with SMTP id k19mr748174eji.476.1594661307342; Mon, 13 Jul 2020 10:28:27 -0700 (PDT) Received: from localhost ([2620:10d:c093:400::5:ef88]) by smtp.gmail.com with ESMTPSA id gu15sm10117140ejb.111.2020.07.13.10.28.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jul 2020 10:28:26 -0700 (PDT) Date: Mon, 13 Jul 2020 18:28:26 +0100 From: Chris Down To: Andrew Morton Cc: Hugh Dickins , Al Viro , Matthew Wilcox , Amir Goldstein , Jeff Layton , Johannes Weiner , Tejun Heo , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v7 2/2] tmpfs: Support 64-bit inums per-sb Message-ID: <8b23758d0c66b5e2263e08baf9c4b6a7565cbd8f.1594661218.git.chris@chrisdown.name> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.14.5 (2020-06-23) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The default is still set to inode32 for backwards compatibility, but system administrators can opt in to the new 64-bit inode numbers by either: 1. Passing inode64 on the command line when mounting, or 2. Configuring the kernel with CONFIG_TMPFS_INODE64=y The inode64 and inode32 names are used based on existing precedent from XFS. Signed-off-by: Chris Down Reviewed-by: Amir Goldstein Cc: Hugh Dickins Cc: Andrew Morton Cc: Al Viro Cc: Matthew Wilcox Cc: Jeff Layton Cc: Johannes Weiner Cc: Tejun Heo Cc: linux-mm@kvack.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: kernel-team@fb.com Acked-by: Hugh Dickins --- Documentation/filesystems/tmpfs.rst | 11 +++++ fs/Kconfig | 15 +++++++ include/linux/shmem_fs.h | 1 + mm/shmem.c | 65 ++++++++++++++++++++++++++++- 4 files changed, 90 insertions(+), 2 deletions(-) diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst index 4e95929301a5..47b84ddaa8bb 100644 --- a/Documentation/filesystems/tmpfs.rst +++ b/Documentation/filesystems/tmpfs.rst @@ -150,6 +150,15 @@ These options do not have any effect on remount. You can change these parameters with chmod(1), chown(1) and chgrp(1) on a mounted filesystem. +tmpfs has a mount option to select whether it will wrap at 32- or 64-bit inode +numbers: + +inode64 Use 64-bit inode numbers +inode32 Use 32-bit inode numbers + +On 64-bit, the default is set by CONFIG_TMPFS_INODE64. On 32-bit, inode64 is +not legal and will produce an error at mount time. + So 'mount -t tmpfs -o size=10G,nr_inodes=10k,mode=700 tmpfs /mytmpfs' will give you tmpfs instance on /mytmpfs which can allocate 10GB RAM/SWAP in 10240 inodes and it is only accessible by root. @@ -161,3 +170,5 @@ RAM/SWAP in 10240 inodes and it is only accessible by root. Hugh Dickins, 4 June 2007 :Updated: KOSAKI Motohiro, 16 Mar 2010 +Updated: + Chris Down, 13 July 2020 diff --git a/fs/Kconfig b/fs/Kconfig index ff257b81fde5..64d530ba42f6 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -229,6 +229,21 @@ config TMPFS_XATTR If unsure, say N. +config TMPFS_INODE64 + bool "Use 64-bit ino_t by default in tmpfs" + depends on TMPFS && 64BIT + default n + help + tmpfs has historically used only inode numbers as wide as an unsigned + int. In some cases this can cause wraparound, potentially resulting in + multiple files with the same inode number on a single device. This option + makes tmpfs use the full width of ino_t by default, similarly to the + inode64 mount option. + + To override this default, use the inode32 or inode64 mount options. + + If unsure, say N. + config HUGETLBFS bool "HugeTLB file system support" depends on X86 || IA64 || SPARC64 || (S390 && 64BIT) || \ diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index eb628696ec66..a5a5d1d4d7b1 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -36,6 +36,7 @@ struct shmem_sb_info { unsigned char huge; /* Whether to try for hugepages */ kuid_t uid; /* Mount uid for root directory */ kgid_t gid; /* Mount gid for root directory */ + bool full_inums; /* If i_ino should be uint or ino_t */ ino_t next_ino; /* The next per-sb inode number to use */ ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ struct mempolicy *mpol; /* default memory policy for mappings */ diff --git a/mm/shmem.c b/mm/shmem.c index 0ae250b4da28..f3126ad7ba3d 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -114,11 +114,13 @@ struct shmem_options { kuid_t uid; kgid_t gid; umode_t mode; + bool full_inums; int huge; int seen; #define SHMEM_SEEN_BLOCKS 1 #define SHMEM_SEEN_INODES 2 #define SHMEM_SEEN_HUGE 4 +#define SHMEM_SEEN_INUMS 8 }; #ifdef CONFIG_TMPFS @@ -286,12 +288,17 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) ino = sbinfo->next_ino++; if (unlikely(is_zero_ino(ino))) ino = sbinfo->next_ino++; - if (unlikely(ino > UINT_MAX)) { + if (unlikely(!sbinfo->full_inums && + ino > UINT_MAX)) { /* * Emulate get_next_ino uint wraparound for * compatibility */ - ino = 1; + if (IS_ENABLED(CONFIG_64BIT)) + pr_warn("%s: inode number overflow on device %d, consider using inode64 mount option\n", + __func__, MINOR(sb->s_dev)); + sbinfo->next_ino = 1; + ino = sbinfo->next_ino++; } *inop = ino; } @@ -304,6 +311,10 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) * unknown contexts. As such, use a per-cpu batched allocator * which doesn't require the per-sb stat_lock unless we are at * the batch boundary. + * + * We don't need to worry about inode{32,64} since SB_KERNMOUNT + * shmem mounts are not exposed to userspace, so we don't need + * to worry about things like glibc compatibility. */ ino_t *next_ino; next_ino = per_cpu_ptr(sbinfo->ino_batch, get_cpu()); @@ -3397,6 +3408,8 @@ enum shmem_param { Opt_nr_inodes, Opt_size, Opt_uid, + Opt_inode32, + Opt_inode64, }; static const struct constant_table shmem_param_enums_huge[] = { @@ -3416,6 +3429,8 @@ const struct fs_parameter_spec shmem_fs_parameters[] = { fsparam_string("nr_inodes", Opt_nr_inodes), fsparam_string("size", Opt_size), fsparam_u32 ("uid", Opt_uid), + fsparam_flag ("inode32", Opt_inode32), + fsparam_flag ("inode64", Opt_inode64), {} }; @@ -3487,6 +3502,18 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param) break; } goto unsupported_parameter; + case Opt_inode32: + ctx->full_inums = false; + ctx->seen |= SHMEM_SEEN_INUMS; + break; + case Opt_inode64: + if (sizeof(ino_t) < 8) { + return invalfc(fc, + "Cannot use inode64 with <64bit inums in kernel\n"); + } + ctx->full_inums = true; + ctx->seen |= SHMEM_SEEN_INUMS; + break; } return 0; @@ -3578,8 +3605,16 @@ static int shmem_reconfigure(struct fs_context *fc) } } + if ((ctx->seen & SHMEM_SEEN_INUMS) && !ctx->full_inums && + sbinfo->next_ino > UINT_MAX) { + err = "Current inum too high to switch to 32-bit inums"; + goto out; + } + if (ctx->seen & SHMEM_SEEN_HUGE) sbinfo->huge = ctx->huge; + if (ctx->seen & SHMEM_SEEN_INUMS) + sbinfo->full_inums = ctx->full_inums; if (ctx->seen & SHMEM_SEEN_BLOCKS) sbinfo->max_blocks = ctx->blocks; if (ctx->seen & SHMEM_SEEN_INODES) { @@ -3619,6 +3654,29 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root) if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, sbinfo->gid)); + + /* + * Showing inode{64,32} might be useful even if it's the system default, + * since then people don't have to resort to checking both here and + * /proc/config.gz to confirm 64-bit inums were successfully applied + * (which may not even exist if IKCONFIG_PROC isn't enabled). + * + * We hide it when inode64 isn't the default and we are using 32-bit + * inodes, since that probably just means the feature isn't even under + * consideration. + * + * As such: + * + * +-----------------+-----------------+ + * | TMPFS_INODE64=y | TMPFS_INODE64=n | + * +------------------+-----------------+-----------------+ + * | full_inums=true | show | show | + * | full_inums=false | show | hide | + * +------------------+-----------------+-----------------+ + * + */ + if (IS_ENABLED(CONFIG_TMPFS_INODE64) || sbinfo->full_inums) + seq_printf(seq, ",inode%d", (sbinfo->full_inums ? 64 : 32)); #ifdef CONFIG_TRANSPARENT_HUGEPAGE /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */ if (sbinfo->huge) @@ -3667,6 +3725,8 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) ctx->blocks = shmem_default_max_blocks(); if (!(ctx->seen & SHMEM_SEEN_INODES)) ctx->inodes = shmem_default_max_inodes(); + if (!(ctx->seen & SHMEM_SEEN_INUMS)) + ctx->full_inums = IS_ENABLED(CONFIG_TMPFS_INODE64); } else { sb->s_flags |= SB_NOUSER; } @@ -3684,6 +3744,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) } sbinfo->uid = ctx->uid; sbinfo->gid = ctx->gid; + sbinfo->full_inums = ctx->full_inums; sbinfo->mode = ctx->mode; sbinfo->huge = ctx->huge; sbinfo->mpol = ctx->mpol;