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FSTAB(5)		    BSD	File Formats Manual		      FSTAB(5)

     fstab -- static information about the filesystems

     #include <fstab.h>

     The file fstab contains descriptive information about the various file
     systems.  fstab is	only read by programs, and not written;	it is the duty
     of	the system administrator to properly create and	maintain this file.
     Each filesystem is	described on a separate	line; fields on	each line are
     separated by tabs or spaces.  The order of	records	in fstab is important
     because fsck(8), mount(8),	and umount(8) sequentially iterate through
     fstab doing their thing.

     The first field, (fs_spec), describes the block special device or remote
     filesystem	to be mounted.	For filesystems	of type	ufs, the special file
     name is the block special file name, and not the character	special	file
     name.  If a program needs the character special file name,	the program
     must create it by appending a ``r'' after the last	``/'' in the special
     file name.

     The second	field, (fs_file), describes the	mount point for	the filesys-
     tem.  For swap partitions,	this field should be specified as ``none''.

     The third field, (fs_vfstype), describes the type of the filesystem.  The
     system can	support	various	filesystem types.  Only	the root, /usr,	and
     /tmp filesystems need be statically compiled into the kernel; everything
     else will be automatically	loaded at mount	time.  (Exception: the UFS
     family - FFS, MFS,	and LFS	cannot currently be demand-loaded.)  Some peo-
     ple still prefer to statically compile other filesystems as well.

	   ufs	   a local UNIX	filesystem

	   mfs	   a local memory-based	UNIX filesystem

	   nfs	   a Sun Microsystems compatible ``Network File	System''

	   swap	   a disk partition to be used for swapping

	   msdos   a DOS compatible filesystem

	   cd9660  a CD-ROM filesystem (as per ISO 9660)

	   procfs  a file system for accessing process data

     The fourth	field, (fs_mntops), describes the mount	options	associated
     with the filesystem.  It is formatted as a	comma separated	list of	op-
     tions.  It	contains at least the type of mount (see fs_type below)	plus
     any additional options appropriate	to the filesystem type.	 See the op-
     tions flag	(-o) in	the mount(8) page and the filesystem specific page,
     such as mount_nfs(8), for additional options that may be specified.

     If	the options ``userquota'' and/or ``groupquota''	are specified, the
     filesystem	is automatically processed by the quotacheck(8)	command, and
     user and/or group disk quotas are enabled with quotaon(8).	 By default,
     filesystem	quotas are maintained in files named quota.user	and which are located at the root of the associated filesystem.
     These defaults may	be overridden by putting an equal sign and an alterna-
     tive absolute pathname following the quota	option.	 Thus, if the user
     quota file	for /tmp is stored in /var/quotas/tmp.user, this location can
     be	specified as:


     If	the option ``noauto'' is specified, the	filesystem will	not be auto-
     matically mounted at system startup.  This	is recommended for all remote
     filesystems other than NFS, since only NFS	mounts are delayed until after
     network initialization by the rc startup scripts.

     The type of the mount is extracted	from the fs_mntops field and stored
     separately	in the fs_type field (it is not	deleted	from the fs_mntops
     field).  If fs_type is ``rw'' or ``ro'' then the filesystem whose name is
     given in the fs_file field	is normally mounted read-write or read-only on
     the specified special file.  If fs_type is	``sw'' then the	special	file
     is	made available as a piece of swap space	by the swapon(8) command at
     the end of	the system reboot procedure.  The fields other than fs_spec
     and fs_type are unused.  If fs_type is specified as ``xx''	the entry is
     ignored.  This is useful to show disk partitions which are	currently un-

     The fifth field, (fs_freq), is used for these filesystems by the dump(8)
     command to	determine which	filesystems need to be dumped.	If the fifth
     field is not present, a value of zero is returned and dump	will assume
     that the filesystem does not need to be dumped.

     The sixth field, (fs_passno), is used by the fsck(8) program to determine
     the order in which	filesystem checks are done at reboot time.  The	root
     filesystem	should be specified with a fs_passno of	1, and other filesys-
     tems should have a	fs_passno of 2.	 Filesystems within a drive will be
     checked sequentially, but filesystems on different	drives will be checked
     at	the same time to utilize parallelism available in the hardware.	 If
     the sixth field is	not present or is zero,	a value	of zero	is returned
     and fsck(8) will assume that the filesystem does not need to be checked.

     #define FSTAB_RW	     "rw"    /*	read/write device */
     #define FSTAB_RQ	     "rq"    /*	read/write with	quotas */
     #define FSTAB_RO	     "ro"    /*	read-only device */
     #define FSTAB_SW	     "sw"    /*	swap device */
     #define FSTAB_XX	     "xx"    /*	ignore totally */

     struct fstab {
	     char    *fs_spec;	     /*	block special device name */
	     char    *fs_file;	     /*	filesystem path	prefix */
	     char    *fs_vfstype;    /*	File system type, ufs, nfs */
	     char    *fs_mntops;     /*	Mount options ala -o */
	     char    *fs_type;	     /*	FSTAB_*	from fs_mntops */
	     int     fs_freq;	     /*	dump frequency,	in days	*/
	     int     fs_passno;	     /*	pass number on parallel	fsck */

     The proper	way to read records from fstab is to use the routines
     getfsent(3), getfsspec(3),	getfstype(3), and getfsfile(3).

     /etc/fstab	 The file fstab	resides	in /etc.

     getfsent(3), getvfsbyname(3), dump(8), fsck(8), mount(8), quotacheck(8),
     quotaon(8), swapon(8), umount(8)

     The fstab file format appeared in 4.0BSD.

BSD				 June 5, 1993				   BSD


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