Modify libxl to allow raw format file to use phy backend.
For the hotplug script part, learn from NetBSD's block hotplug script --
test the path and determine the actual type of file (block device or
regular file) then use the actual type to determine which branch to run.
With these changes, plus the current ordering of backend preference
(phy > qdisk > tap), we will use phy backend for raw format file by
default.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
These are provided using the "script=" syntax described in
docs/misc/xl-disk-configuration.txt.
The existing hotplug scripts currently conflate two different
concepts, namely that of making a datapath available in the backend
domain (logging into iSCSI LUNs and the like) and that of actually
connecting that datapath to a Xen backend path (e.g. writing
"physical-device" node in xenstore to bring up blkback).
For this reason the script support implemented here is only supported
in conjunction with backendtype=phy.
Eventually we hope to rework the hotplug scripts to separate the to
concepts, but that is not 4.2 material.
In addition there are some other subtleties:
- Previously in the blktap case we would add "script = .../blktap" to
the backend flex array, but then jumped to the PHY case which added
"script = .../block" too. The block one takes precendence since it
comes second.
This was, accidentally, correct. The blktap script is for blktap1
devices and not blktap2 devices. libxl completely manages the
blktap2 side of things without resorting to hotplug scripts and
creates a blkback device directly. Therefore the "block" script is
always the correct one to call. Custom script are not supported in
this context.
- libxl should not write the "physical-device" node. This is the
responsibility of the block script. Writing the "physical-device"
node in libxl basically completely short-cuts the standard block
hotplug script which uses "physical-device" to know if it has run
already or not.
In the case of more complex scripts libxl cannot know the right
value to write here anyway, in particular the device may not exist
until after the script is called.
This change has the side effect of re-enabling the checks for
device sharing aspect of the default block script, which I have tested
and which now cause libxl to properly abort now that libxl properly
checks for hotplug script errors.
There is no sharing check for blktap2 since even if you reuse the
same vhd the resulting tap device is different. I would have preferred
to simply write the "physical-device" node for the blktap2 case but
the hotplug script infrastructure is not currently setup to handle
LIBXL__DEVICE_KIND_VBD
devices without a hotplug script (backendtype phy and tap both end
up as KIND_VBD). Changing this was more surgery than I was happy doing
for 4.2 and therefore I have simply hardcoded to the block script for
the LIBXL_DISK_BACKEND_TAP case.
- libxl__device_disk_set_backend running against a phy device with a
script cannot stat the device to check its properties since it may
not exist until the script is run. Therefore I have special cased
this in disk_try_backend to simply assume that backend == phy is
always ok if a script was
configured. Similarly the other backend types are always rejected
if a script was configured.
Note that the reason for implementing the default script behaviour
in device_disk_add instead of libxl__device_disk_setdefault is
because we need to be able to tell when the script was
user-supplied rather than defaulted by libxl in order to correctly
implement the above. The setdefault function must be idempotent so
we cannot simply update disk->script.
I suspect that for 4.3 a script member should be added to
libxl__device, this would also help in the case above of handling
devices with no script in a consistent manner. This is not 4.2
material.
- When the block script falls through and shells out to a block-$type
script it used to pass "$node" however the only place this was
assigned was in the remove+phy case (in which case it contains the
file:// derived /dev/loopN device), and in that case the script
exits without falling through to the block-$type case.
Since libxl never creates a type other than phy this never happens
in practice anyway and we now call the correct block-$type script
directly. But fix it up anyway since it is confusing.
- The block-nbd and block-enbd scripts which we supply appear to be
broken WRT the hotplug calling convention, in that they seem to
expect a command line parameter (perhaps the $node described above)
rather than reading the appropriate node from xenstore.
I rather suspect this was broken by 7774:e2e7f47e6f79 in November
2005. I think it is safe to say no one is using these scripts! I
haven't fixed this here. It would be good to track down some working
scripts and either incorproate them or defer to them in their existing
home (e.g. if they live somewhere useful like the nbd tools
package).
- Added a few block script related entries to check-xl-disk-parse
from http://backdrift.org/xen-block-iscsi-script-with-multipath-support
and http://lists.linbit.com/pipermail/drbd-user/2008-September/010221.html /
http://www.drbd.org/users-guide-emb/s-xen-configure-domu.html (and
snuck in another interesting empty CDROM case)
This highlighted two bugs in the libxlu disk parser handling of the
deprecated "<script>:" prefix:
- It was failing to prefix with "block-" to construct the actual
script name
- The regex for matching iscsi or drdb or e?nbd was incorrect
- Use libxl__abs_path for the nic script too. Just because the
existing code nearly tricked me into repeating the mistake
I have tested with a custom block script which uses "lvchange -a" to
dynamically add remove the referenced device (simulates iSCSI
login/logout without requiring me to faff around setting up an iSCSI
target). I also tested on a blktap2 system.
I haven't directly tested anything more complex like iscsi: or nbd:
other than what check-xl-disk-parse exercises.
[ Recommit of correct version of 25727:a8d708fcb347, which was mangled
during commit. Sorry. -iwj ]
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
These are provided using the "script=" syntax described in
docs/misc/xl-disk-configuration.txt.
The existing hotplug scripts currently conflate two different
concepts, namely that of making a datapath available in the backend
domain (logging into iSCSI LUNs and the like) and that of actually
connecting that datapath to a Xen backend path (e.g. writing
"physical-device" node in xenstore to bring up blkback).
For this reason the script support implemented here is only supported
in conjunction with backendtype=phy.
Eventually we hope to rework the hotplug scripts to separate the to
concepts, but that is not 4.2 material.
In addition there are some other subtleties:
- Previously in the blktap case we would add "script = .../blktap" to
the backend flex array, but then jumped to the PHY case which added
"script = .../block" too. The block one takes precendence since it
comes second.
This was, accidentally, correct. The blktap script is for blktap1
devices and not blktap2 devices. libxl completely manages the
blktap2 side of things without resorting to hotplug scripts and
creates a blkback device directly. Therefore the "block" script is
always the correct one to call. Custom script are not supported in
this context.
- libxl should not write the "physical-device" node. This is the
responsibility of the block script. Writing the "physical-device"
node in libxl basically completely short-cuts the standard block
hotplug script which uses "physical-device" to know if it has run
already or not.
In the case of more complex scripts libxl cannot know the right
value to write here anyway, in particular the device may not exist
until after the script is called.
This change has the side effect of re-enabling the checks for
device sharing aspect of the default block script, which I have tested
and which now cause libxl to properly abort now that libxl properly
checks for hotplug script errors.
There is no sharing check for blktap2 since even if you reuse the
same vhd the resulting tap device is different. I would have preferred
to simply write the "physical-device" node for the blktap2 case but
the hotplug script infrastructure is not currently setup to handle
LIBXL__DEVICE_KIND_VBD
devices without a hotplug script (backendtype phy and tap both end
up as KIND_VBD). Changing this was more surgery than I was happy doing
for 4.2 and therefore I have simply hardcoded to the block script for
the LIBXL_DISK_BACKEND_TAP case.
- libxl__device_disk_set_backend running against a phy device with a
script cannot stat the device to check its properties since it may
not exist until the script is run. Therefore I have special cased
this in disk_try_backend to simply assume that backend == phy is
always ok if a script was
configured. Similarly the other backend types are always rejected
if a script was configured.
Note that the reason for implementing the default script behaviour
in device_disk_add instead of libxl__device_disk_setdefault is
because we need to be able to tell when the script was
user-supplied rather than defaulted by libxl in order to correctly
implement the above. The setdefault function must be idempotent so
we cannot simply update disk->script.
I suspect that for 4.3 a script member should be added to
libxl__device, this would also help in the case above of handling
devices with no script in a consistent manner. This is not 4.2
material.
- When the block script falls through and shells out to a block-$type
script it used to pass "$node" however the only place this was
assigned was in the remove+phy case (in which case it contains the
file:// derived /dev/loopN device), and in that case the script
exits without falling through to the block-$type case.
Since libxl never creates a type other than phy this never happens
in practice anyway and we now call the correct block-$type script
directly. But fix it up anyway since it is confusing.
- The block-nbd and block-enbd scripts which we supply appear to be
broken WRT the hotplug calling convention, in that they seem to
expect a command line parameter (perhaps the $node described above)
rather than reading the appropriate node from xenstore.
I rather suspect this was broken by 7774:e2e7f47e6f79 in November
2005. I think it is safe to say no one is using these scripts! I
haven't fixed this here. It would be good to track down some working
scripts and either incorproate them or defer to them in their existing
home (e.g. if they live somewhere useful like the nbd tools
package).
- Added a few block script related entries to check-xl-disk-parse
from http://backdrift.org/xen-block-iscsi-script-with-multipath-support
and http://lists.linbit.com/pipermail/drbd-user/2008-September/010221.html /
http://www.drbd.org/users-guide-emb/s-xen-configure-domu.html (and
snuck in another interesting empty CDROM case)
This highlighted two bugs in the libxlu disk parser handling of the
deprecated "<script>:" prefix:
- It was failing to prefix with "block-" to construct the actual
script name
- The regex for matching iscsi or drdb or e?nbd was incorrect
- Use libxl__abs_path for the nic script too. Just because the
existing code nearly tricked me into repeating the mistake
I have tested with a custom block script which uses "lvchange -a" to
dynamically add remove the referenced device (simulates iSCSI
login/logout without requiring me to faff around setting up an iSCSI
target). I also tested on a blktap2 system.
I haven't directly tested anything more complex like iscsi: or nbd:
other than what check-xl-disk-parse exercises.
[ reran flex/bison -iwj ]
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
We need to cope with 0 or more '0' prefixed to '$dev':
# stat -c '%D' "/system.img"
13
# losetup -a
/dev/loop0: [0013]:12062248 (/system.img)
Signed-off-by: Zhigang Wang <zhigang.x.wang@oracle.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Improve busy loop device detection after changeset 22773:02c0af2bf280
The intention is not to find the file to be mounted in the losetup -a
output. What matters are existing mounted files with the same dev:inode
as the new file. So the fix is to apply variable expansion which
happens only without double quotes. Otherwise $dev will contain
newlines for hardlinked files, as mentioned in the commit message from
the changeset above.
losetup -a does also truncate long filenames to 62 chars due to ioctl
limitations. This part is fixed with 2.6.37 where the filename can be
obtained from sysfs. As a result very long filenames will be missed.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
tools/hotplug/Linux/block change for this losetup -a output:
(inode 12 is listed twice due to hardlinks)
/dev/loop0: [0809]:139267 (/abuild/vdisk-sles11_2-disk0)
/dev/loop1: [0809]:139266 (/abuild/vdisk-sles11_1-disk1)
/dev/loop3: [0809]:139267 (/abuild/vdisk-sles11_2-disk0)
/dev/loop5: [0809]:139273 (/abuild/vdisk-sles11_5-disk1)
/dev/loop8: [0809]:12 (/abuild/bootiso-xenpaging-sles11_5.iso)
/dev/loop10: [0809]:12 (/abuild/bootiso-xenpaging-sles11_4.iso)
/dev/loop11: [0809]:139271 (/abuild/vdisk-sles11_4-disk0)
Without this change, $dev would contain /dev/loop8\n/dev/loop10
Applies to 4.0 and 4.1
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
c/s 20393 breaks existing domain configuration that contains
spaces in the vbd path name. Fixed by this trivial patch which
provides missing quotes.
Signed-off-by: Jim Fehlig <jfehlig@novell.com>
The failure to read "backend/tap/<domid>/*" in the xenstore is a usual
case since the domain is gone after xenstore-ls command is executed.
The error should be ignored.
Signed-off-by: Kouya Shimura <kouya@jp.fujitsu.com>
- Use the device and inode information provided by losetup to find
if the vbd backing file is in use on another vbd.
- Use losetup to find a free loopback device.
Signed-off-by: Gary Grebus <gary.grebus@oracle.com>
Avoid races between hotplug "add" and "remove" leading to "leaked"
loopback devices.
- Don't setup loopback device if xend is no longer waiting for the
vbd.
- Use the lock file to avoid add/remove races.
Signed-off-by: Gary Grebus <gary.grebus@oracle.com>
- Have the buid system generate a file which exports the install paths
for the hotplug scripts and stubdom / stubdom-dm
- Move file generation code from tools/python/Makefile into a gmake
macro
in Config.mk to avoid maintenance of three duplicates each with its
own
tweaks and bugs
- Export gmake variables into ioemu as shell variables
for upcoming ioemu patches
- Do above as a gmake macro to avoid maintenance of several duplicates
- Adjust hotplug scripts to find the right xen binaries from the
install directory
- Adjust stubdom-dm to use the install directories
Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
Allow 'file' based disks, that are blkback based disks, to be shared
between the guest domain and the stubdom. It does so exploiting the
same exception introduced in the previous patch "stubdoms phy disks
sharing". Now we can remove the hack in stubdom-dm that forces "file"
disks to be opened using blktap instead of blkback.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Ian Campbell
Wei Liu
Ian Jackson
Zhigang Wang
Olaf Hering
Keir Fraser