VOP_BMAP — Logical to physical block number conversion

       This manual page was written by Alan Somers.

Debian                                            June 19, 2019                                      VOP_BMAP(9)

       This  vnode call is used to lookup the physical block number of the file system's underlying device where
       a given logical block of a file is stored.  Its arguments are:

       vp    The vnode of the file.

       bn    Logical block number within the file identified by vp.

       bop   Return storage for the buffer object associated with the file system's underlying device.

       bnp   Return storage for the physical block number.

       runp  Return storage for the number of succeeding logical blocks that may be efficiently read at the same
             time as the requested block.  This will usually be the number  of  logical  blocks  whose  physical
             blocks  are  contiguously allocated.  However a file system is free to define "efficient" as it see
             fit.

       runb  Like runp but for preceding rather than succeeding blocks.

       Any of the return arguments may be NULL to indicate that the caller does not care about that information.

       A bmap() function first appeared in 4.2BSD.

       The vnode will be locked on entry and should remain locked on return.

       VOP_BMAP — Logical to physical block number conversion

       Zero is returned on success, otherwise an error code is returned.

vnode(9),

#include<sys/param.h>#include<sys/vnode.h>intVOP_BMAP(structvnode*vp, daddr_tbn, structbufobj**bop, daddr_t*bnp, int*runp, int*runb);