NAME
vnsubr,
vn_bwrite,
vn_close,
vn_default_error,
vn_isunder,
vn_lock,
vn_markexec,
vn_marktext,
vn_rdwr,
vn_open,
vn_stat,
vn_writechk —
high-level convenience functions for vnode operations
SYNOPSIS
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/vnode.h>
int
vn_bwrite(
void
*ap);
int
vn_close(
struct
vnode *vp,
int flags,
kauth_cred_t cred);
int
vn_default_error(
void
*v);
int
vn_isunder(
struct
vnode *dvp,
struct vnode
*rvp,
struct lwp *l);
int
vn_lock(
struct
vnode *vp,
int
flags);
void
vn_markexec(
struct
vnode *vp);
void
vn_marktext(
struct
vnode *vp);
int
vn_open(
struct
nameidata *ndp,
int
fmode,
int cmode);
int
vn_rdwr(
enum uio_rw rw,
struct vnode *vp,
void *base,
int len,
off_t offset,
enum uio_seg segflg,
int ioflg,
kauth_cred_t cred,
size_t *aresid,
struct lwp *l);
int
vn_readdir(
file_t
*fp,
char *buf,
int segflg,
u_int count,
int *done,
struct lwp *l,
off_t **cookies,
int *ncookies);
int
vn_stat(
struct
vnode *vp,
struct stat
*sb);
int
vn_writechk(
struct
vnode *vp);
DESCRIPTION
The high-level functions described in this page are convenience functions for
simplified access to the vnode operations described in
vnodeops(9).
FUNCTIONS
-
-
- vn_bwrite(ap)
- Common code for block write operations.
-
-
- vn_close(vp,
flags, cred)
- Common code for a vnode close. The argument
vp is the unlocked vnode of the vnode to close.
vn_close() simply locks the vnode, invokes the vnode
operation VOP_CLOSE(9)
and calls vput() to return the vnode to the freelist or
holdlist. Note that vn_close() expects an unlocked,
referenced vnode and will dereference the vnode prior to returning. If the
operation is successful zero is returned, otherwise an appropriate error
is returned.
-
-
- vn_default_error(v)
- A generic "default" routine that just returns
error. It is used by a file system to specify unsupported operations in
the vnode operations vector.
-
-
- vn_isunder(dvp,
rvp, l)
- Common code to check if one directory specified by the
vnode rvp can be found inside the directory
specified by the vnode dvp. The argument
l is the calling process.
vn_isunder() is intended to be used in
chroot(2),
chdir(2),
fchdir(2), etc., to ensure
that chroot(2) actually
means something. If the operation is successful zero is returned,
otherwise 1 is returned.
-
-
- vn_lock(vp,
flags)
- Common code to acquire the lock for vnode
vp. The argument flags
specifies the flags used to lock the vnode. There are the following flags:
- LK_SHARED
- shared lock
- LK_EXCLUSIVE
- exclusive lock
- LK_NOWAIT
- do not sleep to await lock
- LK_RETRY
- allow lock operation on dead vnode
If the operation is successful zero is returned, otherwise an appropriate
error code is returned.
vn_lock() must not be called when the vnode's reference
count is zero.
-
-
- vn_markexec(vp)
- Common code to mark the vnode vp as
containing executable code of a running process.
-
-
- vn_marktext(vp)
- Common code to mark the vnode vp as
being the text of a running process.
-
-
- vn_open(ndp,
fmode, cmode)
- Common code for vnode open operations. The pathname is
described in the nameidata pointer (see
namei(9)). The arguments
fmode and cmode specify the
open(2) file mode and the
access permissions for creation. vn_open() checks
permissions and invokes the
VOP_OPEN(9) or
VOP_CREATE(9) vnode
operations. If the operation is successful zero is returned and the vnode
is locked, otherwise an appropriate error code is returned.
-
-
- vn_rdwr(rw,
vp, base,
len, offset,
segflg, ioflg,
cred, aresid,
l)
- Common code to package up an I/O request on a vnode into a
uio and then perform the I/O. The argument rw
specifies whether the I/O is a read (
UIO_READ
) or
write (UIO_WRITE
) operation. The vnode is
specified by vp. The arguments
l and cred are the calling lwp
and its credentials. If ioflg contains
IO_NODELOCKED
, it is expected that the vnode is
locked. ioflg will be passed to
VOP_READ()/VOP_WRITE().
The remaining arguments specify the uio parameters. For further
information on these parameters see
uiomove(9).
-
-
- vn_readdir(fp,
buf, segflg,
count, done,
l, cookies,
ncookies)
- Common code for reading the contents of a directory. The
argument fp is the file structure,
buf is the buffer for placing the struct dirent
structures. The arguments cookies and
ncookies specify the addresses for the list and
number of directory seek cookies generated for NFS. Both
cookies and ncookies should be
NULL
if they aren't required to be returned by
vn_readdir(). If the operation is successful zero is
returned, otherwise an appropriate error code is returned.
-
-
- vn_stat(vp,
sb)
- Common code for a vnode stat operation. The vnode is
specified by the argument vp, and
sb is the buffer to return the stat information.
vn_stat() basically calls the vnode operation
VOP_GETATTR(9) and
transfers the contents of a vattr structure into a struct stat. If the
operation is successful zero is returned, otherwise an appropriate error
code is returned.
-
-
- vn_writechk(vp)
- Common code to check for write permission on the vnode
vp. A vnode is read-only if it is in use as a
process's text image. If the vnode is read-only ETEXTBSY is returned,
otherwise zero is returned to indicate that the vnode can be written
to.
ERRORS
-
-
- [
EBUSY
]
- The LK_NOWAIT flag was set and vn_lock()
would have slept.
-
-
- [
ENOENT
]
- The vnode has been reclaimed and is dead. This error is
only returned if the LK_RETRY flag is not passed to
vn_lock().
-
-
- [
ETXTBSY
]
- Cannot write to a vnode since is a process's text
image.
CODE REFERENCES
The high-level convenience functions are implemented within the files
sys/kern/vfs_vnops.c and
sys/sys/vnode.h.
SEE ALSO
file(9),
intro(9),
lock(9),
namei(9),
vattr(9),
vfs(9),
vnode(9),
vnodeops(9)