From patchwork Tue Feb 6 20:18:51 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kent Overstreet X-Patchwork-Id: 13547769 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 ECA7218AF8 for ; Tue, 6 Feb 2024 20:19:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707250754; cv=none; b=O2FSbU3BnbvahNTYc7Du0ExO9vuK0g+l35cZ9MkRzlLP/afOSPaAEcPSCFZBaJMLD521+MoQyPik/o/97EFe2F3GwMgFhk38xCrDevdXgNN4fgha7CiRR1h93gpVtNKe7KiIuTdK6p9qG6ocamgTWGR8m6XWByR4llNvMmF/jxA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707250754; c=relaxed/simple; bh=Nl2uD7WLGO6LwYrdmtsTqVkhwhbUvhZiQtCqAfnLPOg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PrseR3PLVsn3s9zsQsIMGJDcUiDsd5OAwcx9VdBXh7nFB24HnorJXn8J3XUvE4r+4LQA0+YflTGUin5Z//8WmFHr/15E75xuJUodMflMF2lBjTiFWZf8fRv4RnbgSFOJ6rT0NGWYd8AhL+PutmyIkWg3GC6U30fM4uCPzkNn3xg= 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=pD1lnZx2; arc=none smtp.client-ip=91.218.175.181 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="pD1lnZx2" 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=1707250750; 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=cUWUWQYx2apHh584Rw7/E+yXOteLWIl9kYmQ30+LMmM=; b=pD1lnZx25k66T6d8cUseYkNdiKRM6rwnY7db3KlIqpszfG+WRNa4M1ZLVrYl1A5UUzrmlA 8rmQRWHdrv4nbzS32Te2wHIF16jdGH71+IzPLqbBBg6SSCH1L8qPJgUkC7bCt2ZnLaKxJB wp1uqbhAlwB5wC7OhMFhbRH6xiWI87c= From: Kent Overstreet To: brauner@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Kent Overstreet , Jan Kara , Dave Chinner , "Darrick J. Wong" , Theodore Ts'o , linux-fsdevel@vger.kernel.or Subject: [PATCH v2 3/7] fs: FS_IOC_GETUUID Date: Tue, 6 Feb 2024 15:18:51 -0500 Message-ID: <20240206201858.952303-4-kent.overstreet@linux.dev> In-Reply-To: <20240206201858.952303-1-kent.overstreet@linux.dev> References: <20240206201858.952303-1-kent.overstreet@linux.dev> Precedence: bulk X-Mailing-List: linux-fsdevel@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. We're not lifting SETFSUUID from ext4 - that can be done on offline filesystems by the people who need it, trying to do it online is just asking for too much trouble. 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 | 17 +++++++++++++++++ 2 files changed, 33 insertions(+) diff --git a/fs/ioctl.c b/fs/ioctl.c index 76cf22ac97d7..046c30294a82 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 (!sb->s_uuid_len) + return -ENOIOCTLCMD; + + struct fsuuid2 u = { .len = sb->s_uuid_len, }; + memcpy(&u.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..16a6ecadfd8d 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -64,6 +64,19 @@ 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 { + __u8 len; + __u8 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 @@ -190,6 +203,9 @@ struct fsxattr { * (see uapi/linux/blkzoned.h) */ +/* Returns the external filesystem UUID, the same one blkid returns */ +#define FS_IOC_GETFSUUID _IOR(0x12, 142, struct fsuuid2) + #define BMAP_IOCTL 1 /* obsolete - kept for compatibility */ #define FIBMAP _IO(0x00,1) /* bmap access */ #define FIGETBSZ _IO(0x00,2) /* get the block size used for bmap */ @@ -198,6 +214,7 @@ struct fsxattr { #define FITRIM _IOWR('X', 121, struct fstrim_range) /* Trim */ #define FICLONE _IOW(0x94, 9, int) #define FICLONERANGE _IOW(0x94, 13, struct file_clone_range) + #define FIDEDUPERANGE _IOWR(0x94, 54, struct file_dedupe_range) #define FSLABEL_MAX 256 /* Max chars for the interface; each fs may differ */