mount.2nfs

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)mount.2nfs	8.2	12/3/90
.TH mount 2nfs
.SH Name
mount, umount \- mount or remove an NFS file system
.SH Syntax
#include <sys/types.h>
.br
#include <sys/fs_types.h>
.sp
mount(\fIspecial, name, rwflag, type, options\fP)
.br
char \fI*special, *name\fP;
.br
int \fIrwflag, type\fP;
.br
char \fI*options\fP;
.PP
.ft B
.B umount(\fIdev\fP)
.br
.B dev_t \fIdev\fP;
.SH Description
.NXB "mount system call (NFS)"
.NXB "NFS file system" "mounting remote"
.NXR "umount system call (NFS)"
The 
.PN mount
system call announces to the system that a remote NFS file system has
been mounted on
directory
.I name.
References to file
.I name
refer to
the root file on the newly mounted file system.
.PP
The 
.I special 
argument is a pointer to a null-terminated string containing
the pathname of the file system being mounted. It is of the form: 
.EX
host:pathname
.EE
The 
.I name 
argument is a pointer to a null-terminated string containing the
pathname of the root file on the newly mounted file system.
The
.I name
must already exist and must be a directory.
Its old contents
are inaccessible while the file system
is mounted.
.PP
The
.I rwflag
argument is used to determine whether
the file system can be written to; if it is 0, the file system is writable,
if nonzero, the file system is write-protected.
.PP
The 
.I type 
argument identifies the file system type that is being mounted.
The DEFINE statement for the
.I nfs
type is:
.EX
#define GT_NFS   0x04 
.EE
The
.I nfs 
file system type is defined in the <fs_types.h> file.
.PP
The 
.I options 
argument specifies certain parameters that can be used to define how
the file system is to be mounted.  The
.MS mount(8nfs)
description lists the available NFS options.
.PP
./" THE FOLLOWING COMMENTED-OUT TEXT HAS BEEN LEFT IN FOR HISTORICAL
./" PURPOSES.  THE TEXT IS FROM THE ORIGINAL NFS MOUNT ROUTINE AND MAY
./" NEEDED AT A LATER DATE.
./"The
./".I data
./"argument is a pointer to a structure which contains the type-specific
./"arguments to mount.  Below is a list of the filesystem types supported
./"and the type specific arguments to each:
./".nf
./".ta \w'#include'u +\w'fhandle_t\0\0'u +\w'retrans;\0\0'u
./".TP 4
./".B MOUNT_UFS
./"struct ufs_args {
./"	char    *fspec;		/* Block special file to mount */
./"};
./".TP 4
./".B MOUNT_NFS
./"#include	<nfs/nfs.h>
./"#include	<netinet/in.h>
./"struct nfs_args {
./"	struct sockaddr_in  *addr;  /* file server address */
./"	fhandle_t	*fh;	/* File handle to be mounted */
./"	int	flags;	/* flags */
./"	int	wsize;	/* write size in bytes */
./"	int	rsize;	/* read size in bytes */
./"	int	timeo;	/* initial timeout in .1 secs */
./"	int	retrans;	/* times to retry send */
./"};
./".fi

.PP
The following structure is used by the 
.PN nfs_mount 
user-level
routine as the fifth argument when making a 
.PN mount 
system call.
.EX 0
struct nfs_gfs_mount {                                        
       struct sockaddr_in addr;   /* File server address /* 
       fhandle_t  fh;             /* File handle to be mounted /* 
       int   flags;               /* Flags handler /*         
       int   wsize;               /* Write size in bytes /*     
       int   rsize;               /* Read size in bytes /*       
       int   timeo;               /* Initial timeout in .1 secs. /* 
       int   retrans;             /* Times to retry send /*   
       char *hostname;            /* Server's host name /*     
       char *optstr;              /* Options string /*
       int   gfs_flags;           /* GFS flags /*
       int   pg_thresh;           /* Page threshold for exec /*
    };
.EE
.SH Return Values
The
.PN mount
system call returns a value of 0 upon successful completion of a 
operation, \-1 if the operation fails.  
.PP
The
.PN umount
system call announces to the system that the remote file system mounted
on directory
.I name 
is no longer available.
The directory 
.I name 
reverts to its ordinary interpretation.
.PP
The
.PN umount
system call
returns 0 if the dismount operation succeeds, \-1 if it fails.  
.SH Diagnostics
.NXR "mount system call (NFS)" "diagnostics"
The
.PN mount
call fails under the following conditions:
.TP 15
[EPERM]
The caller is not the superuser and is not the owner of the mount point.
.TP 15
[ENODEV]
A component
of
.I special
does not exist.
.TP 15
[EINVAL]
The pathname contains a character with the high-order bit set.
.TP 15
[ENOTDIR]
A component of
.I name
is not a directory.
.TP 15
[EBUSY]
Another process currently holds a reference to
.I name.
.TP 15
[ENAMETOOLONG]
A component of the pathname exceeded 255 characters,
or the entire length of the pathname exceeded 1023
characters.
.TP 15
[ELOOP]
Too many symbolic links were encountered in translating
the pathname.
.TP 15
[ENOENT]
A component of
.I name
does not exist.
.TP 15
[EMFILE]
No space remains in the mount table.
.TP 15
[EFAULT]
The
.I special
or
.I name
points outside the process's allocated address space space.
.TP 15
[ESTALE]
The 
.I fhandle
given in the argument was invalid.  The file referred to by
that file handle no longer exists or has been revoked.
.PP
The
.PN umount
call fails under the following conditions:
.TP 15
[EPERM]
The caller is not the superuser and is not the owner of the mount point.
.TP 15
[EINVAL]
The requested mounted-on directory is not in the mount table.
.TP 15
[EBUSY]
A process is holding a reference to a file located
on the file system.
.TP 15
[EIO]
An I/O error occurred while writing cached file system information.
.SH See Also
mount(2), gfsi(5), mount(8nfs)
.NXE "mount system call (NFS)"
.NXE "NFS file system" "mounting remote"