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From: Eric Sandeen <>
To: Eric Sandeen <>,
	fsdevel <>,
	"" <>,
	Linux API <>,
	"Michael Kerrisk (man-pages)" <>
Subject: [PATCH 2/2] man2: New page documenting filesystem get/set label ioctls
Date: Wed, 9 May 2018 11:04:03 -0500	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

This documents the proposed new vfs-level ioctls which can
get or set a mounted filesytem's label.

Signed-off-by: Eric Sandeen <>

btrfs folks, please verify that this accurately describes your
current behavior, thanks.

diff --git a/man2/ioctl_fslabel.2 b/man2/ioctl_fslabel.2
new file mode 100644
index 0000000..150aa53
--- /dev/null
+++ b/man2/ioctl_fslabel.2
@@ -0,0 +1,83 @@
+.\" Copyright (c) 2018, Red Hat, Inc.  All rights reserved.
+.\" This is free documentation; you can redistribute it and/or
+.\" modify it under the terms of the GNU General Public License as
+.\" published by the Free Software Foundation; either version 2 of
+.\" the License, or (at your option) any later version.
+.\" The GNU General Public License's references to "object code"
+.\" and "executables" are to be interpreted as the output of any
+.\" document formatting or typesetting system, including
+.\" intermediate and printed output.
+.\" This manual is distributed in the hope that it will be useful,
+.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
+.\" GNU General Public License for more details.
+.\" You should have received a copy of the GNU General Public
+.\" License along with this manual; if not, see
+.\" <>.
+.TH IOCTL-FSLABEL 2 2018-05-02 "Linux" "Linux Programmer's Manual"
+ioctl_fslabel \- get or set a filesystem label
+.B #include <sys/ioctl.h>
+.B #include <linux/fs.h>
+.BI "int ioctl(int " fd ", FS_IOC_GETFSLABEL, char " label [FSLABEL_MAX]);
+.BI "int ioctl(int " fd ", FS_IOC_SETFSLABEL, char " label [FSLABEL_MAX]);
+If a filesystem supports online label manipulation, these
+.BR ioctl (2)
+operations can be used to get or set the filesystem label for the filesystem
+on which
+.B fd
+On success zero is returned.  On error, \-1 is returned, and
+.I errno
+is set to indicate the error.
+Error codes can be one of, but are not limited to, the following:
+The specified label exceeds the maximum label length for the filesystem.
+This can appear if the filesystem does not support online label manipulation.
+The calling process does not have sufficient permissions to set the label.
+.I label
+references an inaccessible memory area.
+These ioctl operations first appeared in Linux 4.18.
+They were previously known as
+and were private to Btrfs.
+This API is Linux-specific.
+The maximum string length for this interface is
+including the terminating null byte (\(aq\\0\(aq).
+Filesystems have differing maximum label lengths, which may or
+may not include the terminating null.  The string provided to
+must always be null-terminated, and the string returned by
+will always be null-terminated.
+.BR ioctl (2),
+.BR blkid (8)
diff --git a/man2/ioctl_getfslabel.2 b/man2/ioctl_getfslabel.2
new file mode 100644
index 0000000..bfa8dca
--- /dev/null
+++ b/man2/ioctl_getfslabel.2
@@ -0,0 +1 @@ man2/ioctl_fslabel.2
diff --git a/man2/ioctl_setfslabel.2 b/man2/ioctl_setfslabel.2
new file mode 100644
index 0000000..bfa8dca
--- /dev/null
+++ b/man2/ioctl_setfslabel.2
@@ -0,0 +1 @@ man2/ioctl_fslabel.2

  parent reply	other threads:[~2018-05-09 16:04 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09 15:56 [PATCH 0/2] hoist btrfs' label set/get ioctls to vfs, and document Eric Sandeen
2018-05-09 16:01 ` [PATCH 1/2] fs: hoist BTRFS_IOC_[SG]ET_FSLABEL to vfs Eric Sandeen
2018-05-09 16:10   ` Darrick J. Wong
2018-05-09 17:15     ` Andreas Dilger
2018-05-09 17:26       ` Darrick J. Wong
2018-05-09 17:35   ` Randy Dunlap
2018-05-09 17:40     ` Eric Sandeen
2018-05-09 21:35   ` David Sterba
2018-05-10 18:13   ` [PATCH 1/2 V2] " Eric Sandeen
2018-05-10 19:16     ` Al Viro
2018-05-11 14:10       ` David Sterba
2018-05-11 14:32         ` [PATCH 1/2 V2] " Chris Mason
2018-05-11 14:36           ` Eric Sandeen
2018-05-11 14:41             ` David Sterba
2018-05-12  0:20               ` Darrick J. Wong
2018-05-09 16:04 ` Eric Sandeen [this message]
2018-05-09 16:15   ` [PATCH 2/2] man2: New page documenting filesystem get/set label ioctls Darrick J. Wong
2018-05-10 17:29   ` [PATCH 2/2 V2] " Eric Sandeen
2018-05-10 17:35     ` Eric Sandeen
2020-04-20 12:04     ` Michael Kerrisk (man-pages)
2020-04-20 13:48       ` Eric Sandeen
2020-04-20 15:29         ` Michael Kerrisk (man-pages)

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