From patchwork Fri Jul 1 20:11:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Bongio X-Patchwork-Id: 12903714 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 7952BCCA47F for ; Fri, 1 Jul 2022 20:12:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232495AbiGAUMq (ORCPT ); Fri, 1 Jul 2022 16:12:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232459AbiGAULy (ORCPT ); Fri, 1 Jul 2022 16:11:54 -0400 Received: from mail-pg1-x52d.google.com (mail-pg1-x52d.google.com [IPv6:2607:f8b0:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B31F58FE5; Fri, 1 Jul 2022 13:11:29 -0700 (PDT) Received: by mail-pg1-x52d.google.com with SMTP id s206so3361349pgs.3; Fri, 01 Jul 2022 13:11:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xWWq2l7x4j8QkihvnI7D4BaLA0CA33eSGP54fRTUtZ8=; b=SE0NlNgneYoUCa71nO0MLM7oRAsoepETaKTv8zddYwRrlWEw1qB22rkPq0mhaMfGBm F2Yf5D0cZhic4NNUB0BykZSdDexD3qJ9jiad5/nOJLSoQnhjboUCCkpKzePmar8/Y0Hl J+3voEG61Is30X4LZ/UcH0mJf4MIu39LxW7SKfwCfeJeI+/Mn6LMbr2PnwW/U+2ca6uX sK/B9tNXdzPKnwp+mj2EvBjNujbYLNEU2/9pmzH82yT5ATLy7OkycOya9I+oohc0tvlw IIFGUJjjsiTIbU/KK83AAUeRZ0SWfHYjDwvIyyHrlWxuM0sqhwv3B6f7iQ3pDSz5GLCK P1Xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=xWWq2l7x4j8QkihvnI7D4BaLA0CA33eSGP54fRTUtZ8=; b=WkHkKIL//LUqfu3uygQxk1atgy+pKHV1QP1YV3r4n4+IH9hqBUmLhSRZM73LZiXNVa hCdCTqJfEqdhlvhKxTumQ84HT7/0gXrYJcEor0GTKRftv0CkOvKqPcuKRlSpvuIu9QIS eBgqxPl7kpbixvKs7zY7U+enXCpRD7a9f89EHsBPSCrg39aJ5jLa0FShBzoHbRrmhbUX 3/q93BXxu9NjPrtMuyLno4BDgP44jlJT346Fi7W58n5uhiBlugLnUizvuHN0sQH0V4KJ UWmkU8E36TNhIHwXzpRbEUloLyUX6b/QlqO7cJpC5+18xuNYvCHBDIvTrWYTWqVisTVP trQQ== X-Gm-Message-State: AJIora/+XhkUwxMOlXbWVdregpW7gPxYtch3uGk7ligXhm5G7T+cGjZF pfSkiElJSsNyfDr9LNXVGur0svAXbXE= X-Google-Smtp-Source: AGRyM1urqKvkNTvHimy9bW2FV7QEut7gRKZd2WcpiYS5MOp0FhKpKfZHDOD4Ffa8p1LOpf2RtztzhA== X-Received: by 2002:a05:6a00:d9b:b0:525:7208:3d9 with SMTP id bf27-20020a056a000d9b00b00525720803d9mr21647774pfb.82.1656706288646; Fri, 01 Jul 2022 13:11:28 -0700 (PDT) Received: from jbongio9100214.corp.google.com ([2620:0:102f:1:443b:ca33:8b9a:ccba]) by smtp.googlemail.com with ESMTPSA id k11-20020aa79d0b000000b0050dc76281d3sm16574676pfp.173.2022.07.01.13.11.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 Jul 2022 13:11:28 -0700 (PDT) From: Jeremy Bongio To: Ted Tso Cc: linux-ext4@vger.kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jeremy Bongio Subject: [PATCH v2] Add ioctls to get/set the ext4 superblock uuid. Date: Fri, 1 Jul 2022 13:11:23 -0700 Message-Id: <20220701201123.183468-1-bongiojp@gmail.com> X-Mailer: git-send-email 2.37.0.rc0.161.g10f37bed90-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This fixes a race between changing the ext4 superblock uuid and operations like mounting, resizing, changing features, etc. Reviewed-by: Theodore Ts'o Signed-off-by: Jeremy Bongio --- fs/ext4/ext4.h | 13 ++++++++ fs/ext4/ioctl.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 96 insertions(+) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 75b8d81b2469..0cf960cb591e 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -724,6 +724,8 @@ enum { #define EXT4_IOC_GETSTATE _IOW('f', 41, __u32) #define EXT4_IOC_GET_ES_CACHE _IOWR('f', 42, struct fiemap) #define EXT4_IOC_CHECKPOINT _IOW('f', 43, __u32) +#define EXT4_IOC_GETFSUUID _IOR('f', 44, struct fsuuid) +#define EXT4_IOC_SETFSUUID _IOW('f', 44, struct fsuuid) #define EXT4_IOC_SHUTDOWN _IOR ('X', 125, __u32) @@ -753,6 +755,17 @@ enum { EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT | \ EXT4_IOC_CHECKPOINT_FLAG_DRY_RUN) +/* + * Structure for EXT4_IOC_GETFSUUID/EXT4_IOC_SETFSUUID + */ +struct fsuuid { + __u32 fu_len; + __u32 fu_flags; + __u8 __user fu_uuid[]; +}; + +#define EXT4_IOC_SETFSUUID_FLAG_BLOCKING 0x1 + #if defined(__KERNEL__) && defined(CONFIG_COMPAT) /* * ioctl commands in 32 bit emulation diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index cb01c1da0f9d..75069afc16ae 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "ext4_jbd2.h" #include "ext4.h" #include @@ -41,6 +42,15 @@ static void ext4_sb_setlabel(struct ext4_super_block *es, const void *arg) memcpy(es->s_volume_name, (char *)arg, EXT4_LABEL_MAX); } +/* + * Superblock modification callback function for changing file system + * UUID. + */ +static void ext4_sb_setuuid(struct ext4_super_block *es, const void *arg) +{ + memcpy(es->s_uuid, (__u8 *)arg, UUID_SIZE); +} + static int ext4_update_primary_sb(struct super_block *sb, handle_t *handle, ext4_update_sb_callback func, @@ -1131,6 +1141,73 @@ static int ext4_ioctl_getlabel(struct ext4_sb_info *sbi, char __user *user_label return 0; } +static int ext4_ioctl_getuuid(struct ext4_sb_info *sbi, + struct fsuuid __user *ufsuuid) +{ + int ret = 0; + __u8 uuid[UUID_SIZE]; + struct fsuuid fsuuid; + + if (copy_from_user(&fsuuid, ufsuuid, sizeof(fsuuid))) + return -EFAULT; + + if (fsuuid.fu_len != UUID_SIZE) + return -EINVAL; + + lock_buffer(sbi->s_sbh); + memcpy(uuid, sbi->s_es->s_uuid, UUID_SIZE); + unlock_buffer(sbi->s_sbh); + + if (copy_to_user(&ufsuuid->fu_uuid[0], uuid, UUID_SIZE)) + ret = -EFAULT; + return ret; +} + +static int ext4_ioctl_setuuid(struct file *filp, + const struct fsuuid __user *ufsuuid) +{ + int ret = 0; + struct super_block *sb = file_inode(filp)->i_sb; + struct fsuuid fsuuid; + __u8 uuid[UUID_SIZE]; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + /* + * If any checksums (group descriptors or metadata) are being used + * then the checksum seed feature is required to change the UUID. + */ + if (((ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb)) + && !ext4_has_feature_csum_seed(sb)) + || ext4_has_feature_stable_inodes(sb)) + return -EOPNOTSUPP; + + if (copy_from_user(&fsuuid, ufsuuid, sizeof(fsuuid))) + return -EFAULT; + + if (fsuuid.fu_len != UUID_SIZE) + return -EINVAL; + + if (copy_from_user(uuid, &ufsuuid->fu_uuid[0], UUID_SIZE)) + return -EFAULT; + + ret = mnt_want_write_file(filp); + if (ret) + return ret; + + do { + if (ret == -EBUSY) + msleep(1000); + ret = ext4_update_superblocks_fn(sb, ext4_sb_setuuid, &uuid); + } while (ret == -EBUSY && + fsuuid.fu_flags & EXT4_IOC_SETFSUUID_FLAG_BLOCKING); + + mnt_drop_write_file(filp); + + return ret; +} + static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); @@ -1509,6 +1586,10 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return ext4_ioctl_setlabel(filp, (const void __user *)arg); + case EXT4_IOC_GETFSUUID: + return ext4_ioctl_getuuid(EXT4_SB(sb), (void __user *)arg); + case EXT4_IOC_SETFSUUID: + return ext4_ioctl_setuuid(filp, (const void __user *)arg); default: return -ENOTTY; } @@ -1586,6 +1667,8 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case EXT4_IOC_CHECKPOINT: case FS_IOC_GETFSLABEL: case FS_IOC_SETFSLABEL: + case EXT4_IOC_GETFSUUID: + case EXT4_IOC_SETFSUUID: break; default: return -ENOIOCTLCMD;