nbd: add set flags ioctl

Add a set-flags ioctl, allowing various option flags to be set on an nbd
device.  This allows the nbd-client to set the device flags (to enable
read-only mode, or enable discard support, etc.).

Flags are typically specified by the nbd-server.  During the negotiation
phase of the nbd connection, the server sends its flags to the client.
The client then uses NBD_SET_FLAGS to inform the kernel of the options.

Also included is a one-line fix to debug output for the set-timeout ioctl.

Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Paul Clements
2012-10-04 17:16:15 -07:00
committed by Linus Torvalds
parent de74e00a96
commit 2f01250888
2 changed files with 12 additions and 5 deletions

View File

@@ -27,6 +27,7 @@
#define NBD_SET_SIZE_BLOCKS _IO( 0xab, 7 )
#define NBD_DISCONNECT _IO( 0xab, 8 )
#define NBD_SET_TIMEOUT _IO( 0xab, 9 )
#define NBD_SET_FLAGS _IO( 0xab, 10)
enum {
NBD_CMD_READ = 0,
@@ -34,6 +35,10 @@ enum {
NBD_CMD_DISC = 2
};
/* values for flags field */
#define NBD_FLAG_HAS_FLAGS (1 << 0) /* nbd-server supports flags */
#define NBD_FLAG_READ_ONLY (1 << 1) /* device is read-only */
#define nbd_cmd(req) ((req)->cmd[0])
/* userspace doesn't need the nbd_device structure */
@@ -42,10 +47,6 @@ enum {
#include <linux/wait.h>
#include <linux/mutex.h>
/* values for flags field */
#define NBD_READ_ONLY 0x0001
#define NBD_WRITE_NOCHK 0x0002
struct request;
struct nbd_device {