NAME¶
VOP_ADVISE
—
apply advice about use of file data
SYNOPSIS¶
#include
<sys/param.h>
#include
<sys/vnode.h>
int
VOP_ADVISE
(
struct
vnode *vp,
off_t
start,
off_t
end,
int
advice);
DESCRIPTION¶
This call applies advice for a range of a file's data. It is used to implement
the
posix_fadvise system call.
Its arguments are:
- vp
- The vnode of the file.
- start
- The start of the range of file data.
- end
- The end of the range of file data.
- advice
- The type of operation to apply to the file data. Possible values are:
POSIX_FADV_WILLNEED
- Initiate an asynchronous read of the file data if it is not already
resident.
POSIX_FADV_DONTNEED
- Decrease the in-memory priority of clean file data or discard clean
file data.
If the
start and
end offsets are both zero, then the operation
should be applied to the entire file. Note that this call is advisory only and
may perform the requested operation on a subset of the requested range
(including not performing it at all) and still return success.
LOCKS¶
The file should be unlocked on entry.
RETURN VALUES¶
Zero is returned if the call is successful, otherwise an appropriate error code
is returned.
ERRORS¶
- [
EINVAL
]
- An invalid value was given for
advice.
SEE ALSO¶
vnode(9)