Партнёры:
Хостинг:
fstab - static information about the file systems
The first field, (Fa fs_spec ) describes the special device or remote file system to be mounted.
The second field, (Fa fs_file ) describes the mount point for the file system. For swap partitions, this field should be specified as ``none''.
The third field, (Fa fs_vfstype ) describes the type of the file system. The system can support various file system types. Only the root, /usr, and /tmp file systems need be statically compiled into the kernel; everything else will be automatically loaded at mount time. (Exception: the UFS family - FFS and LFS cannot currently be demand-loaded.) Some people still prefer to statically compile other file systems as well.
The fourth field, (Fa fs_mntops ) describes the mount options associated with the file system. It is formatted as a comma separated list of options. It contains at least the type of mount (see Fa fs_type below) plus any additional options appropriate to the file system type. See the options flag (-o ) in the mount(8) page and the file system specific page, such as mount_nfs8, for additional options that may be specified. All options that can be given to the file system specific mount commands can be used in as well. They just need to be formatted a bit differently. The arguments of the -o option can be used without the preceding -o flag. Other options need both the file system specific flag and its argument, separated by an equal sign. For example, mounting an msdosfs(5) filesystem, the options
-o sync -o noatime -m 644 -M 755 -u foo -g bar
should be written as
sync,noatime,-m=644,-M=755,-u=foo,-g=bar
in the option field of .
If the options ``userquota'' and/or ``groupquota'' are specified, the file system is automatically processed by the quotacheck(8) command, and user and/or group disk quotas are enabled with quotaon(8). By default, file system quotas are maintained in files named quota.user and quota.group which are located at the root of the associated file system. These defaults may be overridden by putting an equal sign and an alternative 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:
userquota=/var/quotas/tmp.user
If the option ``noauto'' is specified, the file system will not be automatically mounted at system startup. Note that, for network file systems of third party types (i.e., types supported by additional software not included in the base system) to be automatically mounted at system startup, the extra_netfs_types rc.conf5 variable must be used to extend the rc(8) startup script's list of network file system types.
The type of the mount is extracted from the Fa fs_mntops field and stored separately in the Fa fs_type field (it is not deleted from the Fa fs_mntops field). If Fa fs_type is ``rw'' or ``ro'' then the file system whose name is given in the Fa fs_file field is normally mounted read-write or read-only on the specified special file. If Fa 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 Fa fs_spec and Fa fs_type are unused. If Fa fs_type is specified as ``xx'' the entry is ignored. This is useful to show disk partitions which are currently unused.
The fifth field, (Fa fs_freq ) is used for these file systems by the dump(8) command to determine which file systems need to be dumped. If the fifth field is not present, a value of zero is returned and dump will assume that the file system does not need to be dumped.
The sixth field, (Fa fs_passno ) is used by the fsck(8) and quotacheck(8) programs to determine the order in which file system and quota checks are done at reboot time. The Fa fs_passno field can be any value between 0 and `INT_MAX' Ns -1 .
The root file system should be specified with a Fa fs_passno of 1, and other file systems should have a Fa fs_passno of 2 or greater. A file system with a Fa fs_passno value of 1 is always checked sequentially and be completed before another file system is processed, and it will be processed before all file systems with a larger Fa fs_passno .
For any given value of Fa fs_passno , file systems within a drive will be checked sequentially, but file systems on different drives will be checked at the same time to utilize parallelism available in the hardware. Once all file system checks are complete for the current Fa fs_passno , the same process will start over for the next Fa fs_passno .
If the sixth field is not present or is zero, a value of zero is returned and fsck(8) and quotacheck(8) will assume that the file system does not need to be checked.
The Fa fs_passno field can be used to implement finer control when the system utilities may determine that the file system resides on a different physical device, when it actually does not, as with a ccd(4) device. All file systems with a lower Fa fs_passno value will be completed before starting on file systems with a higher Fa fs_passno value. E.g. all file systems with a Fa fs_passno of 2 will be completed before any file systems with a Fa fs_passno of 3 or greater are started. Gaps are allowed between the different Fa fs_passno values. E.g. file systems listed in /etc/fstab may have Fa fs_passno values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order within /etc/fstab
#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; /* file system 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).
|
Закладки на сайте Проследить за страницей |
Created 1996-2024 by Maxim Chirkov Добавить, Поддержать, Вебмастеру |