bdflush

BDFLUSH(2)                 Linux Programmer's Manual                BDFLUSH(2)



NAME
       bdflush - start, flush, or tune buffer-dirty-flush daemon

SYNOPSIS
       int bdflush(int func, long *address);
       int bdflush(int func, long data);

DESCRIPTION
       bdflush  starts, flushes, or tunes the buffer-dirty-flush daemon.  Only
       the super-user may call bdflush.

       If func is negative or 0, and no daemon has been started, then  bdflush
       enters the daemon code and never returns.

       If func is 1, some dirty buffers are written to disk.

       If  func  is  2 or more and is even (low bit is 0), then address is the
       address of a long word, and the tuning parameter numbered (func-2)/2 is
       returned to the caller in that address.

       If  func  is  3  or more and is odd (low bit is 1), then data is a long
       word, and the kernel sets tuning parameter numbered (func-3)/2 to  that
       value.

       The set of parameters, their values, and their legal ranges are defined
       in the kernel source file fs/buffer.c.

RETURN VALUE
       If func is negative or 0 and the daemon  successfully  starts,  bdflush
       never  returns.   Otherwise, the return value is 0 on success and -1 on
       failure, with errno set to indicate the error.

ERRORS
       EPERM  Caller is not super-user.

       EFAULT address points outside your accessible address space.

       EBUSY  An attempt was made to enter the daemon code after another  pro-
              cess has already entered.

       EINVAL An  attempt  was made to read or write an invalid parameter num-
              ber, or to write an invalid value to a parameter.

CONFORMING TO
       bdflush is Linux specific and should not be used in  programs  intended
       to be portable.

SEE ALSO
       fsync(2), sync(2), update(8), sync(8)



Linux 1.2.4                       1995-04-15                        BDFLUSH(2)