.Os BSD 4
.Sh NAME
.Nm mount ,
+.Nm fmount,
.Nm unmount
.Nd mount or dismount a filesystem
.Sh SYNOPSIS
.Ft int
.Fn mount "const char *type" "const char *dir" "int flags" "void *data"
.Ft int
+.Fn fmount "const char *type" "int fd" "int flags" "void *data"
+.Ft int
.Fn unmount "const char *dir" "int flags"
.Sh DESCRIPTION
The
.It Dv MNT_RDONLY
The filesystem should be treated as read-only;
Even the super-user may not write on it.
-.It Dv MNT_NOATIME
-Do not update the access time on files in the filesystem unless
-the modification or status change times are also being updated.
.It Dv MNT_NOEXEC
Do not allow files to be executed from the filesystem.
.It Dv MNT_NOSUID
Union with underlying filesystem instead of obscuring it.
.It Dv MNT_SYNCHRONOUS
All I/O to the filesystem should be done synchronously.
+.It Dv MNT_CPROTECT
+Enable data protection on the filesystem if the filesystem is configured for it.
.El
.Pp
The flag
For example,
most filesystems will not allow a change from read-write to read-only.
.Pp
+The flag
+.Dv MNT_RELOAD
+causes the vfs subsystem to update its data structures pertaining to
+the specified already mounted filesystem.
+.Pp
The
.Fa type
argument defines the type of the filesystem.
-The types of filesystems known to the system are defined in
-.Aq Pa sys/mount.h .
+.Pp
.Fa Data
is a pointer to a structure that contains the type
specific arguments to mount.
-The currently supported types of filesystems and
-their type specific data are:
-.Pp
-.Dv MOUNT_FFS
-.Bd -literal -offset indent -compact
-struct ufs_args {
- char *fspec; /* block special file to mount */
- struct export_args export; /* network export information */
-};
-.Ed
+The format for these argument structures is described in the
+manual page for each filesystem.
.Pp
-.Dv MOUNT_NFS
-.Bd -literal -offset indent -compact
-struct nfs_args {
- int version; /* args structure version */
- struct sockaddr *addr; /* file server address */
- int addrlen; /* length of address */
- int sotype; /* Socket type */
- int proto; /* and Protocol */
- u_char *fh; /* File handle to be mounted */
- int fhsize; /* Size, in bytes, of fh */
- int flags; /* flags */
- int wsize; /* write size in bytes */
- int rsize; /* read size in bytes */
- int readdirsize; /* readdir size in bytes */
- int timeo; /* initial timeout in .1 secs */
- int retrans; /* times to retry send */
- int maxgrouplist; /* Max. size of group list */
- int readahead; /* # of blocks to readahead */
- int leaseterm; /* Term (sec) of lease */
- int deadthresh; /* Retrans threshold */
- char *hostname; /* server's name */
-};
-.Ed
-.Pp
-.Dv MOUNT_MFS
-.Bd -literal -offset indent -compact
-struct mfs_args {
- char *fspec; /* name to export for statfs */
- struct export_args export; /* if we can export an MFS */
- caddr_t base; /* base of filesystem in mem */
- u_long size; /* size of filesystem */
-};
-.Ed
+The
+.Fn fmount
+function call is equivalent to the
+.Fn mount
+function call, except in the use of the second argument.
+It takes an open file descriptor representing mount point
+instead of the string literal containing full path to the mount
+point in the filesystem hierarchy.
.Pp
The
-.Fn umount
+.Fn unmount
function call disassociates the filesystem from the specified
mount point
.Fa dir .
.Sh RETURN VALUES
The
.Fn mount
-returns the value 0 if the mount was successful, otherwise -1 is returned
+and
+.Fn fmount
+return the value 0 if the mount was successful, otherwise -1 is returned
and the variable
.Va errno
is set to indicate the error.
.Pp
-.Nm Umount
-returns the value 0 if the umount succeeded; otherwise -1 is returned
+.Nm unmount
+returns the value 0 if the unmount succeeded; otherwise -1 is returned
and the variable
.Va errno
is set to indicate the error.
.Sh ERRORS
-.Fn Mount
+.Fn mount
+and
+.Fn fmount
will fail when one of the following occurs:
.Bl -tag -width [ENAMETOOLONG]
.It Bq Er EPERM
-The caller is not the super-user.
+The caller is not the super-user, and the device-node and the mountpoint
+do not have adequate ownership and permissions.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Dv {NAME_MAX}
points outside the process's allocated address space.
.El
.Pp
-The following errors can occur for a
-.Em ufs
-filesystem mount:
-.Bl -tag -width [ENOTBLK]
-.It Bq Er ENODEV
-A component of ufs_args
-.Ar fspec
-does not exist.
-.It Bq Er ENOTBLK
-.Ar Fspec
-is not a block device.
-.It Bq Er ENXIO
-The major device number of
-.Ar fspec
-is out of range (this indicates no device driver exists
-for the associated hardware).
-.It Bq Er EBUSY
-.Ar Fspec
-is already mounted.
-.It Bq Er EMFILE
-No space remains in the mount table.
-.It Bq Er EINVAL
-The super block for the filesystem had a bad magic
-number or an out of range block size.
-.It Bq Er ENOMEM
-Not enough memory was available to read the cylinder
-group information for the filesystem.
-.It Bq Er EIO
-An I/O error occurred while reading the super block or
-cylinder group information.
-.It Bq Er EFAULT
-.Ar Fspec
-points outside the process's allocated address space.
-.El
-.Pp
-The following errors can occur for a
-.Em nfs
-filesystem mount:
-.Bl -tag -width [ETIMEDOUT]
-.It Bq Er ETIMEDOUT
-.Em Nfs
-timed out trying to contact the server.
-.It Bq Er EFAULT
-Some part of the information described by nfs_args
-points outside the process's allocated address space.
-.El
-.Pp
-The following errors can occur for a
-.Em mfs
-filesystem mount:
-.Bl -tag -width [EMFILE]
-.It Bq Er EMFILE
-No space remains in the mount table.
-.It Bq Er EINVAL
-The super block for the filesystem had a bad magic
-number or an out of range block size.
-.It Bq Er ENOMEM
-Not enough memory was available to read the cylinder
-group information for the filesystem.
-.It Bq Er EIO
-A paging error occurred while reading the super block or
-cylinder group information.
-.It Bq Er EFAULT
-.Em Name
-points outside the process's allocated address space.
-.El
-.Pp
-.Nm Umount
+.Nm unmount
may fail with one of the following errors:
.Bl -tag -width [ENAMETOOLONG]
.It Bq Er EPERM
-The caller is not the super-user.
+The caller is not the super-user, and the
+.Nm mount()
+was not done by the user.
.It Bq Er ENOTDIR
A component of the path is not a directory.
.It Bq Er EINVAL
.Fa Dir
points outside the process's allocated address space.
.El
-.Pp
-A
-.Em ufs
-or
-.Em mfs
-mount can also fail if the maximum number of filesystems are currently
-mounted.
.Sh SEE ALSO
.Xr mount 8 ,
-.Xr umount 8 ,
-.Xr mfs 8
+.Xr unmount 8 ,
+.Xr open 2
.Sh BUGS
Some of the error codes need translation to more obvious messages.
.Sh HISTORY
-.Fn Mount
+.Fn mount
and
-.Fn umount
+.Fn unmount
function calls appeared in
.At v6 .
+.Fn fmount
+function call first appeared in macOS version 10.13.
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