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.
