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xen/tools/blktap2/include/vhd-util.h
T
Keir Fraser bd5573a630 blktap2: a completely rewritten blktap implementation
Benefits to blktap2 over the old version of blktap:

* Isolation from xenstore - Blktap devices are now created directly on
   the linux dom0 command line, rather than being spawned in response
   to XenStore events.  This is handy for debugging, makes blktap
   generally easier to work with, and is a step toward a generic
   user-level block device implementation that is not Xen-specific.

* Improved tapdisk infrastructure: simpler request forwarding, new
   request scheduler, request merging, more efficient use of AIO.

* Improved tapdisk error handling and memory management.  No
   allocations on the block data path, IO retry logic to protect
   guests
   transient block device failures.  This has been tested and is known
   to work on weird environments such as NFS soft mounts.

* Pause and snapshot of live virtual disks (see xmsnap script).

* VHD support.  The VHD code in this release has been rigorously
   tested, and represents a very mature implementation of the VHD
   image
   format.

* No more duplication of mechanism with blkback.  The blktap kernel
   module has changed dramatically from the original blktap.  Blkback
   is now always used to talk to Xen guests, blktap just presents a
   Linux gendisk that blkback can export.  This is done while
   preserving the zero-copy data path from domU to physical device.

These patches deprecate the old blktap code, which can hopefully be
removed from the tree completely at some point in the future.

Signed-off-by: Jake Wires <jake.wires@citrix.com>
Signed-off-by: Dutch Meyer <dmeyer@cs.ubc.ca>
2009-05-26 11:52:31 +01:00

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/* Copyright (c) 2008, XenSource Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of XenSource Inc. nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#ifndef _VHD_UTIL_H_
#define _VHD_UTIL_H_
int vhd_util_create(int argc, char **argv);
int vhd_util_snapshot(int argc, char **argv);
int vhd_util_query(int argc, char **argv);
int vhd_util_read(int argc, char **argv);
int vhd_util_set_field(int argc, char **argv);
int vhd_util_repair(int argc, char **argv);
int vhd_util_fill(int argc, char **argv);
int vhd_util_resize(int argc, char **argv);
int vhd_util_coalesce(int argc, char **argv);
int vhd_util_modify(int argc, char **argv);
int vhd_util_scan(int argc, char **argv);
int vhd_util_check(int argc, char **argv);
int vhd_util_revert(int argc, char **argv);
#endif