Manual pages: mount.8, umount.8: Clarify that "namespace" means "mount namespace"

[thirdparty/util-linux.git] / sys-utils / umount.8

diff --git a/sys-utils/umount.8 b/sys-utils/umount.8
index f94d2f41f4b6e4f48b01b8e0551798763a10fa94..edcb6cc1f9117aa02c8f8309c3fea3e15c268b8a 100644 (file)
--- a/sys-utils/umount.8
+++ b/sys-utils/umount.8
@@ -68,7 +68,8 @@ filesystems. This list of the filesystems may be replaced by \fB\-\-types\fR
 umount option.
 .TP
 .BR \-A , " \-\-all\-targets"
-Unmount all mountpoints in the current namespace for the specified filesystem.
+Unmount all mountpoints in the current mount namespace
+for the specified filesystem.
 The filesystem can be specified by one of the mountpoints or the device name (or
 UUID, etc.).  When this option is used together with \fB\-\-recursive\fR, then
 all nested mounts within the filesystem are recursively unmounted.
@@ -123,25 +124,26 @@ anymore.
 
 A system reboot would be expected in near future if you're going to use this
 option for network filesystem or local filesystem with submounts.  The
-recommended use-case for \fBumount -l\fR is to prevent hangs on shutdown due to
+recommended use-case for \fBumount \-l\fR is to prevent hangs on shutdown due to
 an unreachable network share where a normal umount will hang due to a downed
 server or a network partition. Remounts of the share will not be possible.
 
 .TP
 .BR \-N , " \-\-namespace " \fIns
-Perform umount in namespace specified by \fIns\fR.
+Perform umount in the mount namespace specified by \fIns\fR.
 \fIns\fR is either PID of process running in that namespace
 or special file representing that namespace.
 .sp
 .BR umount (8)
 switches to the namespace when it reads /etc/fstab, writes /etc/mtab (or writes to /run/mount) and calls
 .BR umount (2)
-system call, otherwise it runs in the original namespace. It means that the target namespace does not have
+system call, otherwise it runs in the original namespace.
+It means that the target mount namespace does not have
 to contain any libraries or another requirements necessary to execute
 .BR umount (2)
 command.
 .sp
-See \fBnamespaces\fR(7) for more information.
+See \fBmount_namespaces\fR(7) for more information.
 .TP
 .BR \-n , " \-\-no\-mtab"
 Unmount without writing in
@@ -180,7 +182,7 @@ Note that
 .B umount
 reads information about mounted filesystems from kernel (/proc/mounts) and
 filesystem names may be different than filesystem names used in the /etc/fstab
-(e.g. "nfs4" vs. "nfs").
+(e.g., "nfs4" vs. "nfs").
 .TP
 .BR \-v , " \-\-verbose"
 Verbose mode.
@@ -190,7 +192,26 @@ Display version information and exit.
 .TP
 .BR \-h , " \-\-help"
 Display help text and exit.
-.SH "LOOP DEVICE"
+.SH NON-SUPERUSER UMOUNTS
+Normally, only the superuser can umount filesystems.
+However, when
+.I fstab
+contains the
+.B user
+option on a line, anybody can umount the corresponding filesystem.  For more details see
+.BR mount (8)
+man page.
+.PP
+Since version 2.34 \fBumount\fR command allows to perform umount operation also
+for fuse filesystems if kernel mount table contains user's ID.  In this case fstab
+user= mount option is not required.
+.PP
+Since version 2.35 \fBumount\fR command does not exit when user permissions are
+inadequate by internal libmount security rules.  It drops suid permissions
+and continue as regular non-root user. It allows to support use-cases where
+root permissions are not necessary (e.g., fuse filesystems, user namespaces,
+etc).
+.SH LOOP DEVICE
 The
 .B umount
 command will automatically detach loop device previously initialized by
@@ -200,7 +221,7 @@ command independently of /etc/mtab.
 In this case the device is initialized with "autoclear" flag (see
 .BR losetup (8)
 output for more details), otherwise it's necessary to use the option \fB \-\-detach\-loop\fR
-or call \fBlosetup -d <device>\fR. The autoclear feature is supported since Linux 2.6.25.
+or call \fBlosetup \-d <device>\fR. The autoclear feature is supported since Linux 2.6.25.
 .SH EXTERNAL HELPERS
 The syntax of external unmount helpers is:
 .PP
@@ -234,6 +255,13 @@ to the \fB/sbin/umount.\fItype\fR helper independently of UID.
 .PP
 Note that \fI/etc/mtab\fR is currently deprecated and helper= and another
 userspace mount options are maintained by libmount.
+.SH ENVIRONMENT
+.IP LIBMOUNT_FSTAB=<path>
+overrides the default location of the fstab file (ignored for suid)
+.IP LIBMOUNT_MTAB=<path>
+overrides the default location of the mtab file (ignored for suid)
+.IP LIBMOUNT_DEBUG=all
+enables libmount debug output
 .SH FILES
 .TP
 .I /etc/mtab
@@ -245,21 +273,15 @@ table of known filesystems
 .TP
 .I /proc/self/mountinfo
 table of mounted filesystems generated by kernel.
-.SH ENVIRONMENT
-.IP LIBMOUNT_FSTAB=<path>
-overrides the default location of the fstab file (ignored for suid)
-.IP LIBMOUNT_MTAB=<path>
-overrides the default location of the mtab file (ignored for suid)
-.IP LIBMOUNT_DEBUG=all
-enables libmount debug output
-.SH "SEE ALSO"
-.BR umount (2),
-.BR losetup (8),
-.BR mount (8)
 .SH HISTORY
 A
 .B umount
 command appeared in Version 6 AT&T UNIX.
+.SH SEE ALSO
+.BR umount (2),
+.BR losetup (8),
+.BR mount_namespaces (7)
+.BR mount (8)
 .SH AVAILABILITY
 The umount command is part of the util-linux package and is available from
 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/