From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7D5191DA2E; Mon, 5 Feb 2024 22:27:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707172053; cv=none; b=bGtuY5Ppyxrhsd7saKUYBojtx+QgETQZ/peQZUYtk5pHevh3JYRKgdVqbT/HIwSbsZfYJKbab0rjqoJh4BvGSNckcal/Dyxhq1EJim8rr/2v1DnhXAGJyoHwNVIm3KZorMY50njCLfMrSuVRFOZvcWaF+2NmSq8/gfAVckZvmNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707172053; c=relaxed/simple; bh=VgPZEFsjPxFWOJWslIFFnnk8V9OLOMScwT6wloqjZW4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Zm053e7rvBOl8Sl/JmnZhr8MJEFTR2JSVB9qhmJhj82YBMSsn2H+Ra65yjYGS6xyANvb3On88Dy/LVx2bXmdiO0ZzKWqgIKnndH0VipoTEqe4B28v8vEwwOgayzKzy/vLF+r5vf12a4+E0Gu4ZgKLpTUf8GIel+sCAFAq+bTs0o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VOz8cddh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VOz8cddh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF1E5C433F1; Mon, 5 Feb 2024 22:27:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707172052; bh=VgPZEFsjPxFWOJWslIFFnnk8V9OLOMScwT6wloqjZW4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VOz8cddhQO2oXsZMmqmj55BZxz+lfOZdddnWRhBGgH7aV5jO4z2FqiK0E2dKU+R+z aIfBUn7anrIwfu3ZmJmCe6AszeJq3Lp7YaEuAqeF22fNX2snhvzz+flnhsB6q8Pxf3 OhMs0ff2cjcSyxXEkmADZjphuugzq11kOuzEYUdBH94IN4czgJQW+d5fhCk6gfOkRb +azugqWICyfKC28Od1OVebgk+hgPHUYM5KOh+SwVZf4NmyZNny9Ndok2zPrEopikjw rt1EicSQSBaGcNb+Jz04rcgqydQ80BKVacIx/NPpDm+9icGQ+U8sdGv03UNqqdZb5+ CL1u8ieD9T2Jw== Date: Mon, 5 Feb 2024 14:27:32 -0800 From: "Darrick J. Wong" To: Kent Overstreet Cc: 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, Christian Brauner , Jan Kara , Dave Chinner , Theodore Ts'o , Josef Bacik Subject: Re: [PATCH 4/6] fs: FS_IOC_GETSYSFSNAME Message-ID: <20240205222732.GO616564@frogsfrogsfrogs> References: <20240205200529.546646-1-kent.overstreet@linux.dev> <20240205200529.546646-5-kent.overstreet@linux.dev> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240205200529.546646-5-kent.overstreet@linux.dev> On Mon, Feb 05, 2024 at 03:05:15PM -0500, Kent Overstreet wrote: > Add a new ioctl for getting the sysfs name of a filesystem - the path > under /sys/fs. > > This is going to let us standardize exporting data from sysfs across > filesystems, e.g. time stats. > > The returned path will always be of the form "$FSTYP/$SYSFS_IDENTIFIER", > where the sysfs identifier may be a UUID (for bcachefs) or a device name > (xfs). > > Signed-off-by: Kent Overstreet > Cc: Christian Brauner > Cc: Jan Kara > Cc: Dave Chinner > Cc: "Darrick J. Wong" > Cc: Theodore Ts'o > Cc: Josef Bacik > --- > fs/ioctl.c | 17 +++++++++++++++++ > include/linux/fs.h | 1 + > include/uapi/linux/fs.h | 5 +++++ > 3 files changed, 23 insertions(+) > > diff --git a/fs/ioctl.c b/fs/ioctl.c > index 858801060408..cb3690811d3d 100644 > --- a/fs/ioctl.c > +++ b/fs/ioctl.c > @@ -776,6 +776,20 @@ static int ioctl_getfsuuid(struct file *file, void __user *argp) > return copy_to_user(argp, &u, sizeof(u)) ? -EFAULT : 0; > } > > +static int ioctl_getfssysfsname(struct file *file, void __user *argp) ackpthspacesplease. "ioctl_get_fs_sysfs_name"? > +{ > + struct super_block *sb = file_inode(file)->i_sb; > + > + if (!strlen(sb->s_sysfs_name)) > + return -ENOIOCTLCMD; > + > + struct fssysfsname u = {}; > + > + snprintf(u.name, sizeof(u.name), "%s/%s", sb->s_type->name, sb->s_sysfs_name); Does this actually guarantee that there will be a trailing null in the output? It's really stupid that GETFSLABEL can return an unterminated string if the label is exactly the size of the char array. > + > + 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. > @@ -861,6 +875,9 @@ static int do_vfs_ioctl(struct file *filp, unsigned int fd, > case FS_IOC_GETFSUUID: > return ioctl_getfsuuid(filp, argp); > > + case FS_IOC_GETFSSYSFSNAME: File System Ioctl Get File System System File System Name. Yuck. FS_IOC_GETSYSFSPATH? Also, do we want to establish that this works for /sys/fs and /sys/kernel/debug at the same time? > + return ioctl_getfssysfsname(filp, argp); > + > default: > if (S_ISREG(inode->i_mode)) > return file_ioctl(filp, cmd, argp); > diff --git a/include/linux/fs.h b/include/linux/fs.h > index ff41ea6c3a9c..7f23f593f17c 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1258,6 +1258,7 @@ struct super_block { > char s_id[32]; /* Informational name */ > uuid_t s_uuid; /* UUID */ > u8 s_uuid_len; /* Default 16, possibly smaller for weird filesystems */ > + char s_sysfs_name[UUID_STRING_LEN + 1]; > > unsigned int s_max_links; > > diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h > index 0389fea87db5..6dd14a453277 100644 > --- a/include/uapi/linux/fs.h > +++ b/include/uapi/linux/fs.h > @@ -78,6 +78,10 @@ struct fsuuid2 { > __u8 fsu_uuid[16]; > }; > > +struct fssysfsname { > + __u8 name[64]; > +}; > + > /* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */ > #define FILE_DEDUPE_RANGE_SAME 0 > #define FILE_DEDUPE_RANGE_DIFFERS 1 > @@ -231,6 +235,7 @@ struct fsxattr { > #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) > +#define FS_IOC_GETFSSYSFSNAME _IOR(0x94, 53, struct fssysfsname) 0x94 is btrfs, don't add things to their "name" space. --D > > /* > * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS) > -- > 2.43.0 > >