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Commit 86a54a48 authored by Jonathan Brassow's avatar Jonathan Brassow Committed by Alasdair G Kergon
Browse files

dm log userspace: add version number to comms 



This patch adds a 'version' field to the 'dm_ulog_request'
structure.

The 'version' field is taken from a portion of the unused
'padding' field in the 'dm_ulog_request' structure.  This
was done to avoid changing the size of the structure and
possibly disrupting backwards compatibility.

The version number will help notify user-space daemons
when a change has been made to the kernel/userspace
log API.

Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 085ae065

drivers/md/dm-log-userspace-base.c

+4 −2
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 


#include "dm-log-userspace-transfer.h"



#define DM_LOG_USERSPACE_VSN "1.1.0"



struct flush_entry {

	int type;

	region_t region;
@@ -765,7 +767,7 @@ static int __init userspace_dirty_log_init(void) 
		return r;

	}



	DMINFO("version 1.0.0 loaded");

	DMINFO("version " DM_LOG_USERSPACE_VSN " loaded");

	return 0;

}
@@ -775,7 +777,7 @@ static void __exit userspace_dirty_log_exit(void) 
	dm_ulog_tfr_exit();

	mempool_destroy(flush_entry_pool);



	DMINFO("version 1.0.0 unloaded");

	DMINFO("version " DM_LOG_USERSPACE_VSN " unloaded");

	return;

}

drivers/md/dm-log-userspace-transfer.c

+1 −0
Original line number Diff line number Diff line
@@ -198,6 +198,7 @@ int dm_consult_userspace(const char *uuid, uint64_t luid, int request_type, 


	memset(tfr, 0, DM_ULOG_PREALLOCED_SIZE - sizeof(struct cn_msg));

	memcpy(tfr->uuid, uuid, DM_UUID_LEN);

	tfr->version = DM_ULOG_REQUEST_VERSION;

	tfr->luid = luid;

	tfr->seq = dm_ulog_seq++;

include/linux/dm-log-userspace.h

+12 −1
Original line number Diff line number Diff line
@@ -370,6 +370,16 @@ 
#define DM_ULOG_REQUEST_TYPE(request_type) \

	(DM_ULOG_REQUEST_MASK & (request_type))



/*

 * DM_ULOG_REQUEST_VERSION is incremented when there is a

 * change to the way information is passed between kernel

 * and userspace.  This could be a structure change of

 * dm_ulog_request or a change in the way requests are

 * issued/handled.  Changes are outlined here:

 *	version 1:  Initial implementation

 */

#define DM_ULOG_REQUEST_VERSION 1



struct dm_ulog_request {

	/*

	 * The local unique identifier (luid) and the universally unique
@@ -383,8 +393,9 @@ struct dm_ulog_request { 
	 */

	uint64_t luid;

	char uuid[DM_UUID_LEN];

	char padding[7];        /* Padding because DM_UUID_LEN = 129 */

	char padding[3];        /* Padding because DM_UUID_LEN = 129 */



	uint32_t version;       /* See DM_ULOG_REQUEST_VERSION */

	int32_t error;          /* Used to report back processing errors */



	uint32_t seq;           /* Sequence number for request */