VOP_BMAP(9)            FreeBSD Kernel Developer's Manual           VOP_BMAP(9)

NAME
     VOP_BMAP - Logical to physical block number conversion

SYNOPSIS
     #include <sys/param.h>
     #include <sys/vnode.h>

     int
     VOP_BMAP(struct vnode *vp, daddr_t bn, struct bufobj **bop, daddr_t *bnp,
         int *runp, int *runb);

DESCRIPTION
     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.

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

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

SEE ALSO
     vnode(9)

HISTORY
     A bmap() function first appeared in 4.2BSD.

AUTHORS
     This manual page was written by Alan Somers.

FreeBSD 13.1-RELEASE-p6          June 19, 2019         FreeBSD 13.1-RELEASE-p6