From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932285Ab1IHHps (ORCPT ); Thu, 8 Sep 2011 03:45:48 -0400 Received: from mail-vx0-f174.google.com ([209.85.220.174]:65133 "EHLO mail-vx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932218Ab1IHHpL (ORCPT ); Thu, 8 Sep 2011 03:45:11 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org Cc: Paul Clements , Subject: [PATCH v2 1/2] nbd: add support for feature negotiation Date: Thu, 8 Sep 2011 09:44:57 +0200 Message-Id: <1315467898-23984-2-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.7.6 In-Reply-To: <1315467898-23984-1-git-send-email-pbonzini@redhat.com> References: <1315467898-23984-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a IOCTL to negotiate features between the server and the kernel module, with mediation from the userspace client. Features are stored in the pre-existing (but so far never written to) flags field; bits for the flags field are adjusted to actually match the network protocol. Also, zero out the flags when NBD_DO_IT completes. Cc: Paul Clements Cc: Signed-off-by: Paolo Bonzini --- drivers/block/nbd.c | 10 +++++++++- include/linux/nbd.h | 28 ++++++++++++++-------------- 2 files changed, 23 insertions(+), 15 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index be23aec..c4fe9c8 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -85,6 +85,7 @@ static const char *ioctl_cmd_to_ascii(int cmd) case NBD_PRINT_DEBUG: return "print-debug"; case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; case NBD_DISCONNECT: return "disconnect"; + case NBD_SET_FLAGS: return "set-flags"; case BLKROSET: return "set-read-only"; case BLKFLSBUF: return "flush-buffer-cache"; } @@ -453,7 +453,7 @@ static void nbd_handle_req(struct nbd_device *lo, struct request *req) nbd_cmd(req) = NBD_CMD_READ; if (rq_data_dir(req) == WRITE) { nbd_cmd(req) = NBD_CMD_WRITE; - if (lo->flags & NBD_READ_ONLY) { + if (lo->flags & NBD_FLAG_READ_ONLY) { printk(KERN_ERR "%s: Write on read-only\n", lo->disk->disk_name); goto error_out; @@ -634,6 +635,12 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo, lo->xmit_timeout = arg * HZ; return 0; + case NBD_SET_FLAGS: + if (((u64) arg) & (-1ULL << 32)) + return -EINVAL; + lo->flags = arg; + return 0; + case NBD_SET_SIZE_BLOCKS: lo->bytesize = ((u64) arg) * lo->blksize; bdev->bd_inode->i_size = lo->bytesize; @@ -672,6 +679,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo, printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); if (file) fput(file); + lo->flags = 0; lo->bytesize = 0; bdev->bd_inode->i_size = 0; set_capacity(lo->disk, 0); diff --git a/include/linux/nbd.h b/include/linux/nbd.h index 0582054..926f19d 100644 --- a/include/linux/nbd.h +++ b/include/linux/nbd.h @@ -17,16 +17,20 @@ #include -#define NBD_SET_SOCK _IO( 0xab, 0 ) -#define NBD_SET_BLKSIZE _IO( 0xab, 1 ) -#define NBD_SET_SIZE _IO( 0xab, 2 ) -#define NBD_DO_IT _IO( 0xab, 3 ) -#define NBD_CLEAR_SOCK _IO( 0xab, 4 ) -#define NBD_CLEAR_QUE _IO( 0xab, 5 ) -#define NBD_PRINT_DEBUG _IO( 0xab, 6 ) -#define NBD_SET_SIZE_BLOCKS _IO( 0xab, 7 ) -#define NBD_DISCONNECT _IO( 0xab, 8 ) -#define NBD_SET_TIMEOUT _IO( 0xab, 9 ) +#define NBD_SET_SOCK _IO(0xab, 0) +#define NBD_SET_BLKSIZE _IO(0xab, 1) +#define NBD_SET_SIZE _IO(0xab, 2) +#define NBD_DO_IT _IO(0xab, 3) +#define NBD_CLEAR_SOCK _IO(0xab, 4) +#define NBD_CLEAR_QUE _IO(0xab, 5) +#define NBD_PRINT_DEBUG _IO(0xab, 6) +#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) + +/* values for flags field */ +#define NBD_FLAG_READ_ONLY (1 << 1) enum { NBD_CMD_READ = 0, @@ -42,10 +46,6 @@ enum { #include #include -/* values for flags field */ -#define NBD_READ_ONLY 0x0001 -#define NBD_WRITE_NOCHK 0x0002 - struct request; struct nbd_device { -- 1.7.6