option

linux下的命令

 -o     Options are specified with a -o flag followed by a  comma  sepa-
              rated  string of options.  Some of these options are only useful
              when they appear in the /etc/fstab file.  The following  options
              apply  to  any  file system that is being mounted (but not every
              file system actually honors them - e.g., the sync  option  today
              has effect only for ext2, ext3, fat, vfat and ufs):

              async  All I/O to the file system should be done asynchronously.

              atime  Update inode access time for each  access.  This  is  the
                     default.

              auto   Can be mounted with the -a option.

              defaults
                     Use  default  options: rw, suid, dev, exec, auto, nouser,
                     and async.

              dev    Interpret character or block special devices on the  file
                     system.

              exec   Permit execution of binaries.
                     group  Allow an ordinary (i.e., non-root) user to mount the file
                     system if one of his groups  matches  the  group  of  the
                     device.  This option implies the options nosuid and nodev
                     (unless overridden  by  subsequent  options,  as  in  the
                     option line group,dev,suid).

              mand   Allow mandatory locks on this filesystem. See fcntl(2).

              _netdev
                     The  filesystem resides on a device that requires network
                     access (used to prevent the  system  from  attempting  to
                     mount  these  filesystems  until  the  network  has  been
                     enabled on the system).

              noatime
                     Do not update inode access  times  on  this  file  system
                     (e.g,  for  faster  access  on the news spool to speed up
                     news servers).

              nodiratime
                     Do not  update  directory  inode  access  times  on  this
                     filesystem.

              noauto Can  only be mounted explicitly (i.e., the -a option will
                     not cause the file system to be mounted).

              nodev  Do not interpret character or block  special  devices  on
                     the file system.

              noexec Do  not  allow  direct  execution  of any binaries on the
                     mounted file system.  (Until recently it was possible  to
                     run  binaries  anyway  using  a  command like /lib/ld*.so
                     /mnt/binary.  This  trick  fails  since  Linux  2.4.25  /
                     2.6.0.)

              nomand Do not allow mandatory locks on this filesystem.

              nosuid Do  not allow set-user-identifier or set-group-identifier
                     bits to take effect. (This seems safe,  but  is  in  fact
                     rather unsafe if you have suidperl(1) installed.)
 							nouser Forbid  an  ordinary  (i.e.,  non-root) user to mount the
                     file system.  This is the default.

              owner  Allow an ordinary (i.e., non-root) user to mount the file
                     system  if  he  is  the owner of the device.  This option
                     implies the options nosuid and nodev  (unless  overridden
                     by   subsequent   options,   as   in   the   option  line
                     owner,dev,suid).

              remount
                     Attempt to remount an already-mounted file system.   This
                     is  commonly  used  to  change the mount flags for a file
                     system, especially to make a readonly file system  write-
                     able. It does not change device or mount point.

              ro     Mount the file system read-only.

              rw     Mount the file system read-write.

              suid   Allow set-user-identifier or set-group-identifier bits to
                     take effect.

 				  sync   All I/O to the file system should be done  synchronously.
                     In  case  of  media  with  limited number of write cycles
                     (e.g. some flash  drives)  "sync"  may  cause  life-cycle
                     shortening.

              dirsync
                     All  directory  updates  within the file system should be
                     done synchronously.  This affects  the  following  system
                     calls:  creat, link, unlink, symlink, mkdir, rmdir, mknod
                     and rename.

              user   Allow an ordinary user to mount  the  file  system.   The
                     name  of  the mounting user is written to mtab so that he
                     can unmount the file system again.  This  option  implies
                     the  options noexec, nosuid, and nodev (unless overridden
                     by  subsequent   options,   as   in   the   option   line
                     user,exec,dev,suid).

              users  Allow  every  user  to mount and unmount the file system.
                     This option implies the options noexec, nosuid, and nodev
                     (unless  overridden  by  subsequent  options,  as  in the
                     option line users,exec,dev,suid).