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2017-05-11block: Fix write/resize permissions for inactive imagesKevin Wolf
Format drivers for inactive nodes don't need write/resize permissions on their bs->file and can share write/resize with another VM (in fact, this is the whole point of keeping images inactive). Represent this fact in the op blocker system, so that image locking does the right thing without special-casing inactive images. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-05-11block: Inactivate parents before childrenKevin Wolf
The proper order for inactivating block nodes is that first the parents get inactivated and then the children. If we do things in this order, we can assert that we didn't accidentally leave a parent activated when one of its child nodes is inactive. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-05-11block: Drop permissions when migration completesKevin Wolf
With image locking, permissions affect other qemu processes as well. We want to be sure that the destination can run, so let's drop permissions on the source when migration completes. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-05-11block: New BdrvChildRole.activate() for blk_resume_after_migration()Kevin Wolf
Instead of manually calling blk_resume_after_migration() in migration code after doing bdrv_invalidate_cache_all(), integrate the BlockBackend activation with cache invalidation into a single function. This is achieved with a new callback in BdrvChildRole that is called by bdrv_invalidate_cache_all(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-05-11block: Respect "force-share" in perm propagatingFam Zheng
Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-05-11block: Add, parse and store "force-share" optionFam Zheng
Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-05-11block: Make bdrv_perm_names publicFam Zheng
It can be used outside of block.c for making user friendly messages. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-05-09block: Simplify bdrv_append_temp_snapshot() logicEric Blake
Noticed while checking Coccinelle results. Naming a label 'out:' when it is only used on error paths is weird. Also, we had some dead stores to 'ret'. Meanwhile we know that snapshot_options is NULL on success and that QDECREF(NULL) is safe. So merge the two exit paths into one by careful control over bs_snapshot. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20170427215821.19397-8-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-05-09qobject: Use simpler QDict/QList scalar insertion macrosEric Blake
We now have macros in place to make it less verbose to add a scalar to QDict and QList, so use them. Patch created mechanically via: spatch --sp-file scripts/coccinelle/qobject.cocci \ --macro-file scripts/cocci-macro-file.h --dir . --in-place then touched up manually to fix a couple of '?:' back to original spacing, as well as avoiding a long line in monitor.c. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20170427215821.19397-7-eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-05-08qobject: Drop useless QObject castsEric Blake
We have macros in place to make it less verbose to add a subtype of QObject to both QDict and QList. While we have made cleanups like this in the past (see commit fcfcd8ffc, for example), having it be automated by Coccinelle makes it easier to maintain. Patch created mechanically via: spatch --sp-file scripts/coccinelle/qobject.cocci \ --macro-file scripts/cocci-macro-file.h --dir . --in-place then I verified that no manual touchups were required. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20170427215821.19397-5-eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-04-28block: assert no image modification under BDRV_O_INACTIVEDenis V. Lunev
As long as BDRV_O_INACTIVE is set, the image file is only opened so we have a file descriptor for it. We're definitely not supposed to modify the image, it's still owned by the migration source. This commit is an addition to 09e0c771 but the assert() is added to bdrv_truncate(). Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Kevin Wolf <kwolf@redhat.com> CC: Max Reitz <mreitz@redhat.com> Message-id: 1491405505-31620-3-git-send-email-den@openvz.org Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28block: Add .bdrv_truncate() error messagesMax Reitz
Add missing error messages for the block driver implementations of .bdrv_truncate(); drop the generic one from block.c's bdrv_truncate(). Since one of these changes touches a mis-indented block in block/file-posix.c, this patch fixes that coding style issue along the way. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170328205129.15138-5-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28block: Add errp to BD.bdrv_truncate()Max Reitz
Add an Error parameter to the block drivers' bdrv_truncate() interface. If a block driver does not set this in case of an error, the generic bdrv_truncate() implementation will do so. Where it is obvious, this patch also makes some block drivers set this value. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170328205129.15138-4-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-28block: Add errp to b{lk,drv}_truncate()Max Reitz
For one thing, this allows us to drop the error message generation from qemu-img.c and blockdev.c and instead have it unified in bdrv_truncate(). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170328205129.15138-3-mreitz@redhat.com Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-04-27block: An empty filename counts as no filenameMax Reitz
Reproducer: $ ./qemu-img info '' qemu-img: ./block.c:1008: bdrv_open_driver: Assertion `!drv->bdrv_needs_filename || bs->filename[0]' failed. [1] 26105 abort (core dumped) ./qemu-img info '' This patch fixes this to be: $ ./qemu-img info '' qemu-img: Could not open '': The 'file' block driver requires a file name Cc: qemu-stable <qemu-stable@nongnu.org> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-04-27Revert "block/io: Comment out permission assertions"Max Reitz
This reverts commit e3e0003a8f6570aba1421ef99a0b383a43371a74. This commit was necessary for the 2.9 release because we were unable to fix the underlying issue(s) in time. However, we will be for 2.10. Signed-off-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-04-24block: use bdrv_can_set_read_only() during reopenJeff Cody
Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 00aed7ffdd7be4b9ed9ce1007d50028a72b34ebe.1491597120.git.jcody@redhat.com
2017-04-24block: introduce bdrv_can_set_read_only()Jeff Cody
Introduce check function for setting read_only flags. Will return < 0 on error, with appropriate Error value set. Does not alter any flags. Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: e2bba34ac3bc76a0c42adc390413f358ae0566e8.1491597120.git.jcody@redhat.com
2017-04-24block: code movementJeff Cody
Move bdrv_is_read_only() up with its friends. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Message-id: 73b2399459760c32506f9407efb9dddb3a2789de.1491597120.git.jcody@redhat.com
2017-04-24block: honor BDRV_O_ALLOW_RDWR when clearing bs->read_onlyJeff Cody
The BDRV_O_ALLOW_RDWR flag allows / prohibits the changing of the BDS 'read_only' state, but there are a few places where it is ignored. In the bdrv_set_read_only() helper, make sure to honor the flag. Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: be2e5fb2d285cbece2b6d06bed54a6f56520d251.1491597120.git.jcody@redhat.com
2017-04-24block: do not set BDS read_only if copy_on_read enabledJeff Cody
A few block drivers will set the BDS read_only flag from their .bdrv_open() function. This means the bs->read_only flag could be set after we enable copy_on_read, as the BDRV_O_COPY_ON_READ flag check occurs prior to the call to bdrv->bdrv_open(). This adds an error return to bdrv_set_read_only(), and an error will be return if we try to set the BDS to read_only while copy_on_read is enabled. This patch also changes the behavior of vvfat. Before, vvfat could override the drive 'readonly' flag with its own, internal 'rw' flag. For instance, this -drive parameter would result in a writable image: "-drive format=vvfat,dir=/tmp/vvfat,rw,if=virtio,readonly=on" This is not correct. Now, attempting to use the above -drive parameter will result in an error (i.e., 'rw' is incompatible with 'readonly=on'). Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 0c5b4c1cc2c651471b131f21376dfd5ea24d2196.1491597120.git.jcody@redhat.com
2017-04-24block: add bdrv_set_read_only() helper functionJeff Cody
We have a helper wrapper for checking for the BDS read_only flag, add a helper wrapper to set the read_only flag as well. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 9b18972d05f5fa2ac16c014f0af98d680553048d.1491597120.git.jcody@redhat.com
2017-04-24block: Make errp the last parameter of bdrv_img_createFam Zheng
Signed-off-by: Fam Zheng <famz@redhat.com> Message-Id: <20170421122710.15373-6-famz@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-04-11block/io: Comment out permission assertionsMax Reitz
In case of block migration, there may be writes to BlockBackends that do not have the write permission taken. Before this issue is fixed (which is not going to happen in 2.9), we therefore cannot assert that this is the case. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Tested-by: Kevin Wolf <kwolf@redhat.com> Message-id: 20170411145050.31290-1-mreitz@redhat.com Tested-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-04-11block: Introduce bdrv_coroutine_enterFam Zheng
Signed-off-by: Fam Zheng <famz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2017-04-11block: Quiesce old aio context during bdrv_set_aio_contextFam Zheng
The fact that the bs->aio_context is changing can confuse the dataplane iothread, because of the now fine granularity aio context lock. bdrv_drain should rather be a bdrv_drained_begin/end pair, but since bs->aio_context is changing, we can just use aio_disable_external and bdrv_parent_drained_begin. Reported-by: Ed Swierk <eswierk@skyportsystems.com> Signed-off-by: Fam Zheng <famz@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2017-04-07block: Assert attached child node has right aio contextFam Zheng
Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-04-03block: Document -drive problematic code and bugsMarkus Armbruster
-blockdev and blockdev_add convert their arguments via QObject to BlockdevOptions for qmp_blockdev_add(), which converts them back to QObject, then to a flattened QDict. The QDict's members are typed according to the QAPI schema. -drive converts its argument via QemuOpts to a (flat) QDict. This QDict's members are all QString. Thus, the QType of a flat QDict member depends on whether it comes from -drive or -blockdev/blockdev_add, except when the QAPI type maps to QString, which is the case for 'str' and enumeration types. The block layer core extracts generic configuration from the flat QDict, and the block driver extracts driver-specific configuration. Both commonly do so by converting (parts of) the flat QDict to QemuOpts, which turns all values into strings. Not exactly elegant, but correct. However, A few places access the flat QDict directly: * Most of them access members that are always QString. Correct. * bdrv_open_inherit() accesses a boolean, carefully. Correct. * nfs_config() uses a QObject input visitor. Correct only because the visited type contains nothing but QStrings. * nbd_config() and ssh_config() use a QObject input visitor, and the visited types contain non-QStrings: InetSocketAddress members @numeric, @to, @ipv4, @ipv6. -drive works as long as you don't try to use them (they're all optional). @to is ignored anyway. Reproducer: -drive driver=ssh,server.host=h,server.port=22,server.ipv4,path=p -drive driver=nbd,server.type=inet,server.data.host=h,server.data.port=22,server.data.ipv4 both fail with "Invalid parameter type for 'data.ipv4', expected: boolean" Add suitable comments to all these places. Mark the buggy ones FIXME. "Fortunately", -drive's driver-specific options are entirely undocumented. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-id: 1490895797-29094-5-git-send-email-armbru@redhat.com [mreitz: Fixed two typos] Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-03-17block: quiesce AioContext when detaching from itPaolo Bonzini
While it is true that bdrv_set_aio_context only works on a single BlockDriverState subtree (see commit message for 53ec73e, "block: Use bdrv_drain to replace uncessary bdrv_drain_all", 2015-07-07), it works at the AioContext level rather than the BlockDriverState level. Therefore, it is also necessary to trigger pending bottom halves too, even if no requests are pending. For NBD this ensures that the aio_co_schedule of a previous call to nbd_attach_aio_context is completed before detaching from the old AioContext; it fixes qemu-iotest 094. Another similar bug happens when the VM is stopped and the virtio-blk dataplane irqfd is torn down. In this case it's possible that guest I/O gets stuck if notify_guest_bh was scheduled but doesn't run. Calling aio_poll from another AioContext is safe if non-blocking; races such as the one mentioned in the commit message for c9d1a56 ("block: only call aio_poll on the current thread's AioContext", 2016-10-28) are a concern for blocking calls. I considered other options, including: - moving the bs->wakeup mechanism to AioContext, and letting the caller check. This might work for virtio which has a clear place to wakeup (notify_place_bh) and check the condition (virtio_blk_data_plane_stop). For aio_co_schedule I couldn't find a clear place to check the condition. - adding a dummy oneshot bottom half and waiting for it to trigger. This has the complication that bottom half list is LIFO for historical reasons. There were performance issues caused by bottom half ordering in the past, so I decided against it for 2.9. Fixes: 99723548561978da8ef44cf804fb7912698f5d88 Reported-by: Max Reitz <mreitz@redhat.com> Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com> Tested-by: Halil Pasic <pasic@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20170314111157.14464-2-pbonzini@redhat.com Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-03-17block: Propagate error in bdrv_open_backing_fileFam Zheng
Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-03-17block: Always call bdrv_child_check_perm firstFam Zheng
bdrv_child_set_perm alone is not very usable because the caller must call bdrv_child_check_perm first. This is already encapsulated conveniently in bdrv_child_try_set_perm, so remove the other prototypes from the header and fix the one wrong caller, block/mirror.c. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-03-13block: Refresh filename after changing backing fileKevin Wolf
In bdrv_open_inherit(), the filename is refreshed after opening the backing file, but we neglected to do the same when the backing file changes later. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-13block: Remove check_new_perm from bdrv_replace_child()Kevin Wolf
All callers pass false now, so the parameter can go away again. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-08Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into stagingPeter Maydell
Block layer fixes for 2.9.0-rc0 # gpg: Signature made Tue 07 Mar 2017 14:59:18 GMT # gpg: using RSA key 0x7F09B272C88F2FD6 # gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" # Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6 * remotes/kevin/tags/for-upstream: (27 commits) commit: Don't use error_abort in commit_start block: Don't use error_abort in blk_new_open sheepdog: Support blockdev-add qapi-schema: Rename SocketAddressFlat's variant tcp to inet qapi-schema: Rename GlusterServer to SocketAddressFlat gluster: Plug memory leaks in qemu_gluster_parse_json() gluster: Don't duplicate qapi-util.c's qapi_enum_parse() gluster: Drop assumptions on SocketTransport names sheepdog: Implement bdrv_parse_filename() sheepdog: Use SocketAddress and socket_connect() sheepdog: Report errors in pseudo-filename more usefully sheepdog: Don't truncate long VDI name in _open(), _create() sheepdog: Fix snapshot ID parsing in _open(), _create, _goto() sheepdog: Mark sd_snapshot_delete() lossage FIXME sheepdog: Fix error handling sd_create() sheepdog: Fix error handling in sd_snapshot_delete() sheepdog: Defuse time bomb in sd_open() error handling block: Fix error handling in bdrv_replace_in_backing_chain() block: Handle permission errors in change_parent_backing_link() block: Ignore multiple children in bdrv_check_update_perm() ... Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-03-07block: More detailed syntax error reporting for JSON filenamesMarkus Armbruster
Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <1488317230-26248-14-git-send-email-armbru@redhat.com>
2017-03-07qobject: Propagate parse errors through qobject_from_json()Markus Armbruster
The next few commits will put the errors to use where appropriate. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <1488317230-26248-13-git-send-email-armbru@redhat.com>
2017-03-07block: Fix error handling in bdrv_replace_in_backing_chain()Kevin Wolf
When adding an Error parameter, bdrv_replace_in_backing_chain() would become nothing more than a wrapper around change_parent_backing_link(). So make the latter public, renamed as bdrv_replace_node(), and remove bdrv_replace_in_backing_chain(). Most of the callers just remove a node from the graph that they just inserted, so they can use &error_abort, but completion of a mirror job with 'replaces' set can actually fail. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-07block: Handle permission errors in change_parent_backing_link()Kevin Wolf
Instead of just trying to change parents by parent over to reference @to instead of @from, and abort()ing whenever the permissions don't allow this, do proper permission checking beforehand and pass any error to the callers. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-07block: Ignore multiple children in bdrv_check_update_perm()Kevin Wolf
change_parent_backing_link() will need to update multiple BdrvChild objects at once. Checking permissions reference by reference doesn't work because permissions need to be consistent only with all parents moved to the new child. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-07block: Factor out bdrv_replace_child_noperm()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-07block: Factor out should_update_child()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2017-02-28block: Add Error parameter to bdrv_append()Kevin Wolf
Aborting on error in bdrv_append() isn't correct. This patch fixes it and lets the callers handle failures. Test case 085 needs a reference output update. This is caused by the reversed order of bdrv_set_backing_hd() and change_parent_backing_link() in bdrv_append(): When the backing file of the new node is set, the parent nodes are still pointing to the old top, so the backing blocker is now initialised with the node name rather than the BlockBackend name. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-28block: Add Error parameter to bdrv_set_backing_hd()Kevin Wolf
Not all callers of bdrv_set_backing_hd() know for sure that attaching the backing file will be allowed by the permission system. Return the error from the function rather than aborting. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-28block: Assertions for resize permissionKevin Wolf
This adds an assertion that ensures that the necessary resize permission has been granted before bdrv_truncate() is called. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28block: Allow backing file links in change_parent_backing_link()Kevin Wolf
Now that the backing file child role implements .attach/.detach callbacks, nothing prevents us from modifying the graph even if that involves changing backing file links. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28block: BdrvChildRole.attach/detach() callbacksKevin Wolf
Backing files are somewhat special compared to other kinds of children because they are attached and detached using bdrv_set_backing_hd() rather than the normal set of functions, which does a few more things like setting backing blockers, toggling the BDRV_O_NO_BACKING flag, setting parent_bs->backing_file, etc. These special features are a reason why change_parent_backing_link() can't handle backing files yet. With abstracting the additional features into .attach/.detach callbacks, we get a step closer to a function that can actually deal with this. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28block: Fix pending requests check in bdrv_append()Kevin Wolf
bdrv_append() cares about isolation of the node that it modifies, but not about activity in some subtree below it. Instead of using the recursive bdrv_requests_pending(), directly check bs->in_flight, which considers only the node in question. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28block: Add BdrvChildRole.stay_at_nodeKevin Wolf
When the parents' child links are updated in bdrv_append() or bdrv_replace_in_backing_chain(), this should affect all child links of BlockBackends or other nodes, but not on child links held for other purposes (like for setting permissions). This patch allows to control the behaviour per BdrvChildRole. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-28block: Include details on permission errors in messageKevin Wolf
Instead of just telling that there was some conflict, we can be specific and tell which permissions were in conflict and which way the conflict is. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-28block: Add BdrvChildRole.get_parent_desc()Kevin Wolf
For meaningful error messages in the permission system, we need to get some human-readable description of the parent of a BdrvChild. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>