Make ftruncate a 'struct file' operation rather than a vnode operation.

This makes it possible to support ftruncate() on non-vnode file types in
the future.
- 'struct fileops' grows a 'fo_truncate' method to handle an ftruncate() on
  a given file descriptor.
- ftruncate() moves to kern/sys_generic.c and now just fetches a file
  object and invokes fo_truncate().
- The vnode-specific portions of ftruncate() move to vn_truncate() in
  vfs_vnops.c which implements fo_truncate() for vnode file types.
- Non-vnode file types return EINVAL in their fo_truncate() method.

Submitted by:	rwatson

1 files changed, 14 insertions, 0 deletions

diff --git a/sys/opencrypto/cryptodev.c b/sys/opencrypto/cryptodev.c
index c9fc6d2..fe7372b 100644
--- a/sys/opencrypto/cryptodev.c
+++ b/sys/opencrypto/cryptodev.c
@@ -86,6 +86,8 @@ struct fcrypt {
 
 static	int cryptof_rw(struct file *fp, struct uio *uio,
 		    struct ucred *cred, int flags, struct thread *);
+static	int cryptof_truncate(struct file *, off_t, struct ucred *,
+		    struct thread *);
 static	int cryptof_ioctl(struct file *, u_long, void *,
 		    struct ucred *, struct thread *);
 static	int cryptof_poll(struct file *, int, struct ucred *, struct thread *);
@@ -97,6 +99,7 @@ static	int cryptof_close(struct file *, struct thread *);
 static struct fileops cryptofops = {
     .fo_read = cryptof_rw,
     .fo_write = cryptof_rw,
+    .fo_truncate = cryptof_truncate,
     .fo_ioctl = cryptof_ioctl,
     .fo_poll = cryptof_poll,
     .fo_kqfilter = cryptof_kqfilter,
@@ -129,6 +132,17 @@ cryptof_rw(
 	return (EIO);
 }
 
+static int
+cryptof_truncate(
+	struct file *fp,
+	off_t length,
+	struct ucred *active_cred,
+	struct thread *td)
+{
+
+	return (EINVAL);
+}
+
 /*
  * Check a crypto identifier to see if it requested
  * a software device/driver.  This can be done either