Commit 2f012508 authored by Paul Clements's avatar Paul Clements Committed by Linus Torvalds
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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: default avatarPaul Clements <paul.clements@steeleye.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent de74e00a

drivers/block/nbd.c

+7 −1
Original line number Diff line number Diff line
@@ -78,6 +78,8 @@ static const char *ioctl_cmd_to_ascii(int cmd) 
	case NBD_SET_SOCK: return "set-sock";

	case NBD_SET_BLKSIZE: return "set-blksize";

	case NBD_SET_SIZE: return "set-size";

	case NBD_SET_TIMEOUT: return "set-timeout";

	case NBD_SET_FLAGS: return "set-flags";

	case NBD_DO_IT: return "do-it";

	case NBD_CLEAR_SOCK: return "clear-sock";

	case NBD_CLEAR_QUE: return "clear-que";
@@ -468,7 +470,7 @@ static void nbd_handle_req(struct nbd_device *nbd, struct request *req) 
	nbd_cmd(req) = NBD_CMD_READ;

	if (rq_data_dir(req) == WRITE) {

		nbd_cmd(req) = NBD_CMD_WRITE;

		if (nbd->flags & NBD_READ_ONLY) {

		if (nbd->flags & NBD_FLAG_READ_ONLY) {

			dev_err(disk_to_dev(nbd->disk),

				"Write on read-only\n");

			goto error_out;
@@ -651,6 +653,10 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, 
		nbd->xmit_timeout = arg * HZ;

		return 0;



	case NBD_SET_FLAGS:

		nbd->flags = arg;

		return 0;



	case NBD_SET_SIZE_BLOCKS:

		nbd->bytesize = ((u64) arg) * nbd->blksize;

		bdev->bd_inode->i_size = nbd->bytesize;

include/linux/nbd.h

+5 −4
Original line number Diff line number Diff line
@@ -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 {

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