From patchwork Mon Feb 5 20:05:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kent Overstreet X-Patchwork-Id: 13546210 Received: from out-187.mta0.migadu.com (out-187.mta0.migadu.com [91.218.175.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 95D2C12A177 for ; Mon, 5 Feb 2024 20:06:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.187 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707163570; cv=none; b=IBsyrQ6+9j8MxJZICATmfPa9bWUu+dh7PJATX7FAlTOh9mgCL6jVw3PNbzDbONi48SXtqNjfRITFX2k856QjU7DFPOuslCG0pLs3MZQc5/jVmFK9PwxZNq6yF+v8HOiN17usHOp06nxAY7joxC1zHBPW1ZnbQWPf9dYjmMX5TPs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707163570; c=relaxed/simple; bh=hPLAUyLLwUKEPrP5CZCmbgyMU8k8zrKbJNl29jrSSdk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bQ5JEngN7Vqr33HRs6puw0IAMo7UzXSJWRt7YzFpQRAdmFHwfNgUrhglmWu8OwkC2EetbejiR8rojq/+TqgjLi9j2L88TKYnQRhoNdnKP0bxLSmtz5lZoQjdU6XybjSEiuhIHo4gjxu2y01sT1sY6LaouqHfD9tUUM092/QHG2Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Wcr8U8fQ; arc=none smtp.client-ip=91.218.175.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Wcr8U8fQ" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1707163566; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MqXRwSUVpxeinEtP3l48LwjODcmqmNTThZB6l3iXHHM=; b=Wcr8U8fQCqYiiXre7rQymRda8iHSMIpNPM3+OFYG4WDeLA1Xpd1jwEnMK723HJDBKRO5l0 g0554M9yp0a1oAe+iJ5UMU98kzaBHHllX6DgrX82A0VDgaLHrEBCg1qxgYvy629vbxAx40 HOhKsQ9HMoJfioY7Yt4DCYRG9xNNBNs= From: Kent Overstreet To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org Cc: Kent Overstreet , Christian Brauner , Jan Kara , Dave Chinner , "Darrick J. Wong" , Theodore Ts'o , linux-fsdevel@vger.kernel.or Subject: [PATCH 2/6] fs: FS_IOC_GETUUID Date: Mon, 5 Feb 2024 15:05:13 -0500 Message-ID: <20240205200529.546646-3-kent.overstreet@linux.dev> In-Reply-To: <20240205200529.546646-1-kent.overstreet@linux.dev> References: <20240205200529.546646-1-kent.overstreet@linux.dev> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Add a new generic ioctls for querying the filesystem UUID. These are lifted versions of the ext4 ioctls, with one change: we're not using a flexible array member, because UUIDs will never be more than 16 bytes. This patch adds a generic implementation of FS_IOC_GETFSUUID, which reads from super_block->s_uuid; FS_IOC_SETFSUUID is left for individual filesystems to implement. Signed-off-by: Kent Overstreet Cc: Christian Brauner Cc: Jan Kara Cc: Dave Chinner Cc: "Darrick J. Wong" Cc: Theodore Ts'o Cc: linux-fsdevel@vger.kernel.or Signed-off-by: Kent Overstreet --- fs/ioctl.c | 16 ++++++++++++++++ include/uapi/linux/fs.h | 16 ++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/fs/ioctl.c b/fs/ioctl.c index 76cf22ac97d7..858801060408 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -763,6 +763,19 @@ static int ioctl_fssetxattr(struct file *file, void __user *argp) return err; } +static int ioctl_getfsuuid(struct file *file, void __user *argp) +{ + struct super_block *sb = file_inode(file)->i_sb; + + if (WARN_ON(sb->s_uuid_len > sizeof(sb->s_uuid))) + sb->s_uuid_len = sizeof(sb->s_uuid); + + struct fsuuid2 u = { .fsu_len = sb->s_uuid_len, }; + memcpy(&u.fsu_uuid[0], &sb->s_uuid, sb->s_uuid_len); + + return copy_to_user(argp, &u, sizeof(u)) ? -EFAULT : 0; +} + /* * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. * It's just a simple helper for sys_ioctl and compat_sys_ioctl. @@ -845,6 +858,9 @@ static int do_vfs_ioctl(struct file *filp, unsigned int fd, case FS_IOC_FSSETXATTR: return ioctl_fssetxattr(filp, argp); + case FS_IOC_GETFSUUID: + return ioctl_getfsuuid(filp, argp); + default: if (S_ISREG(inode->i_mode)) return file_ioctl(filp, cmd, argp); diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 48ad69f7722e..0389fea87db5 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -64,6 +64,20 @@ struct fstrim_range { __u64 minlen; }; +/* + * We include a length field because some filesystems (vfat) have an identifier + * that we do want to expose as a UUID, but doesn't have the standard length. + * + * We use a fixed size buffer beacuse this interface will, by fiat, never + * support "UUIDs" longer than 16 bytes; we don't want to force all downstream + * users to have to deal with that. + */ +struct fsuuid2 { + __u32 fsu_len; + __u32 fsu_flags; + __u8 fsu_uuid[16]; +}; + /* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */ #define FILE_DEDUPE_RANGE_SAME 0 #define FILE_DEDUPE_RANGE_DIFFERS 1 @@ -215,6 +229,8 @@ struct fsxattr { #define FS_IOC_FSSETXATTR _IOW('X', 32, struct fsxattr) #define FS_IOC_GETFSLABEL _IOR(0x94, 49, char[FSLABEL_MAX]) #define FS_IOC_SETFSLABEL _IOW(0x94, 50, char[FSLABEL_MAX]) +#define FS_IOC_GETFSUUID _IOR(0x94, 51, struct fsuuid2) +#define FS_IOC_SETFSUUID _IOW(0x94, 52, struct fsuuid2) /* * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)