On Wed, May 09, 2018 at 11:04:03AM -0500, Eric Sandeen wrote: > This documents the proposed new vfs-level ioctls which can > get or set a mounted filesytem's label. > > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > --- > > 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. > +.\" > +.\" %%%LICENSE_START(GPLv2+_DOC_FULL) > +.\" 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 > +.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > +.\" 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 > +.\" <http://www.gnu.org/licenses/>. > +.\" %%%LICENSE_END > +.TH IOCTL-FSLABEL 2 2018-05-02 "Linux" "Linux Programmer's Manual" > +.SH NAME > +ioctl_fslabel \- get or set a filesystem label > +.SH SYNOPSIS > +.br > +.B #include <sys/ioctl.h> > +.br > +.B #include <linux/fs.h> > +.sp > +.BI "int ioctl(int " fd ", FS_IOC_GETFSLABEL, char " label [FSLABEL_MAX]); > +.br > +.BI "int ioctl(int " fd ", FS_IOC_SETFSLABEL, char " label [FSLABEL_MAX]); > +.SH DESCRIPTION > +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 > +resides. Does the calling process need special capabilities or permissions? If so, those should be listed here. > +.SH RETURN VALUE > +On success zero is returned. On error, \-1 is returned, and > +.I errno > +is set to indicate the error. > +.PP > +.SH ERRORS > +Error codes can be one of, but are not limited to, the following: > +.TP > +.B EINVAL > +The specified label exceeds the maximum label length for the filesystem. > +.TP > +.B ENOTTY > +This can appear if the filesystem does not support online label manipulation. > +.TP > +.B EPERM > +The calling process does not have sufficient permissions to set the label. > +.TP > +.B EFAULT > +.I label > +references an inaccessible memory area. > +.SH VERSIONS > +These ioctl operations first appeared in Linux 4.18. > +They were previously known as > +.B BTRFS_IOC_GET_FSLABEL > +and > +.B BTRFS_IOC_SET_FSLABEL > +and were private to Btrfs. > +.SH CONFORMING TO > +This API is Linux-specific. > +.SH NOTES > +The maximum string length for this interface is > +.BR FSLABEL_MAX , > +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 > +.B FS_IOC_SETFSLABEL > +must always be null-terminated, and the string returned by > +.B FS_IOC_GETFSLABEL > +will always be null-terminated. > +.SH SEE ALSO > +.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 @@ > +.so 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 @@ > +.so man2/ioctl_fslabel.2 Put all the manpage content into ioctl_getfslabel.2 and have ioctl_setfslabel.2 point to it, rather than three files. --D > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-api" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html
