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2020-05-18block: Drop @child_class from bdrv_child_perm()Max Reitz
Implementations should decide the necessary permissions based on @role. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-35-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Use bdrv_default_perms()Max Reitz
bdrv_default_perms() can decide which permission profile to use based on the BdrvChildRole, so block drivers do not need to select it explicitly. The blkverify driver now no longer shares the WRITE permission for the image to verify. We thus have to adjust two places in test-block-iothread not to take it. (Note that in theory, blkverify should behave like quorum in this regard and share neither WRITE nor RESIZE for both of its children. In practice, it does not really matter, because blkverify is used only for debugging, so we might as well keep its permissions rather liberal.) Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-30-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Make filter drivers use child_of_bdsMax Reitz
Note that some filters have secondary children, namely blkverify (the image to be verified) and blklogwrites (the log). This patch does not touch those children. Note that for blkverify, the filtered child should not be format-probed. While there is nothing enforcing this here, in practice, it will not be: blkverify implements .bdrv_file_open. The block layer ensures (and in fact, asserts) that BDRV_O_PROTOCOL is set for every BDS whose driver implements .bdrv_file_open. This flag will then be bequeathed to blkverify's children, and they will thus (by default) not be probed either. ("By default" refers to the fact that blkverify's other child (the non-filtered one) will have BDRV_O_PROTOCOL force-unset, because that is what happens for all non-filtered children of non-format drivers.) Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-27-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Pass BdrvChildRole to bdrv_child_perm()Max Reitz
For now, all callers pass 0 and no callee evaluates this value. Later patches will change both. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-7-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Add BdrvChildRole to BdrvChildMax Reitz
For now, it is always set to 0. Later patches in this series will ensure that all callers pass an appropriate combination of flags. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-6-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Rename BdrvChildRole to BdrvChildClassMax Reitz
This structure nearly only contains parent callbacks for child state changes. It cannot really reflect a child's role, because different roles may overlap (as we will see when real roles are introduced), and because parents can have custom callbacks even when the child fulfills a standard role. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-Id: <20200513110544.176672-4-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-01-06blkdebug: Allow taking/unsharing permissionsMax Reitz
Sometimes it is useful to be able to add a node to the block graph that takes or unshare a certain set of permissions for debugging purposes. This patch adds this capability to blkdebug. (Note that you cannot make blkdebug release or share permissions that it needs to take or cannot share, because this might result in assertion failures in the block layer. But if the blkdebug node has no parents, it will not take any permissions and share everything by default, so you can then freely choose what permissions to take and share.) Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20191108123455.39445-4-mreitz@redhat.com Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-06-14blkdebug: Inject errors on .bdrv_co_block_status()Max Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20190507203508.18026-6-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-06-14blkdebug: Add "none" eventMax Reitz
Together with @iotypes and @sector, this can be used to trap e.g. the first read or write access to a certain sector without having to know what happens internally in the block layer, i.e. which "real" events happen right before such an access. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20190507203508.18026-5-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-06-14blkdebug: Add @iotype error optionMax Reitz
This new error option allows users of blkdebug to inject errors only on certain kinds of I/O operations. Users usually want to make a very specific operation fail, not just any; but right now they simply hope that the event that triggers the error injection is followed up with that very operation. That may not be true, however, because the block layer is changing (including blkdebug, which may increase the number of types of I/O operations on which to inject errors). The new option's default has been chosen to keep backwards compatibility. Note that similar to the internal representation, we could choose to expose this option as a list of I/O types. But there is no practical use for this, because as described above, users usually know exactly which kind of operation they want to make fail, so there is no need to specify multiple I/O types at once. In addition, exposing this option as a list would require non-trivial changes to qemu_opts_absorb_qdict(). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20190507203508.18026-4-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-03-26block: Advertise BDRV_REQ_NO_FALLBACK in filter driversKevin Wolf
Filter drivers that support .bdrv_co_pwrite_zeroes can safely advertise BDRV_REQ_NO_FALLBACK because they just forward the request flags to their child node. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Acked-by: Eric Blake <eblake@redhat.com>
2019-02-25block: Purify .bdrv_refresh_filename()Max Reitz
Currently, BlockDriver.bdrv_refresh_filename() is supposed to both refresh the filename (BDS.exact_filename) and set BDS.full_open_options. Now that we have generic code in the central bdrv_refresh_filename() for creating BDS.full_open_options, we can drop the latter part from all BlockDriver.bdrv_refresh_filename() implementations. This also means that we can drop all of the existing default code for this from the global bdrv_refresh_filename() itself. Furthermore, we now have to call BlockDriver.bdrv_refresh_filename() after having set BDS.full_open_options, because the block driver's implementation should now be allowed to depend on BDS.full_open_options being set correctly. Finally, with this patch we can drop the @options parameter from BlockDriver.bdrv_refresh_filename(); also, add a comment on this function's purpose in block/block_int.h while touching its interface. This completely obsoletes blklogwrite's implementation of .bdrv_refresh_filename(). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20190201192935.18394-25-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-02-25block: Add strong_runtime_opts to BlockDriverMax Reitz
This new field can be set by block drivers to list the runtime options they accept that may influence the contents of the respective BDS. As of a follow-up patch, this list will be used by the common bdrv_refresh_filename() implementation to decide which options to put into BDS.full_open_options (and consequently whether a JSON filename has to be created), thus freeing the drivers of having to implement that logic themselves. Additionally, this patch adds the field to all of the block drivers that need it and sets it accordingly. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20190201192935.18394-22-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-07-28qstring: Move qstring_from_substr()'s @end one to the rightMarkus Armbruster
qstring_from_substr() takes the index of the substring's first and last character. qstring_from_substr(s, 0, SIZE_MAX) denotes an empty substring. Awkward. Shift the end index one to the right. This simplifies both qstring_from_substr() and its callers. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180727062204.10401-3-armbru@redhat.com>
2018-07-10block: Use BdrvChild to discardFam Zheng
Other I/O functions are already using a BdrvChild pointer in the API, so make discard do the same. It makes it possible to initiate the same permission checks before doing I/O, and much easier to share the helper functions for this, which will be added and used by write, truncate and copy range paths. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-05-15block: Support BDRV_REQ_WRITE_UNCHANGED in filtersMax Reitz
Update the rest of the filter drivers to support BDRV_REQ_WRITE_UNCHANGED. They already forward write request flags to their children, so we just have to announce support for it. This patch does not cover the replication driver because that currently does not support flags at all, and because it just grabs the WRITE permission for its children when it can, so we should be fine just submitting the incoming WRITE_UNCHANGED requests as normal writes. It also does not cover format drivers for similar reasons. They all use bdrv_format_default_perms() as their .bdrv_child_perm() implementation so they just always grab the WRITE permission for their file children whenever possible. In addition, it often would be difficult to ascertain whether incoming unchanging writes end up as unchanging writes in their files. So we just leave them as normal potentially changing writes. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180421132929.21610-7-mreitz@redhat.com Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-04qobject: Modify qobject_ref() to return objMarc-André Lureau
For convenience and clarity, make it possible to call qobject_ref() at the time when the reference is associated with a variable, or argument, by making qobject_ref() return the same pointer as given. Use that to simplify the callers. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180419150145.24795-5-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Useless change to qobject_ref_impl() dropped, commit message improved slightly] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2018-05-04qobject: Replace qobject_incref/QINCREF qobject_decref/QDECREFMarc-André Lureau
Now that we can safely call QOBJECT() on QObject * as well as its subtypes, we can have macros qobject_ref() / qobject_unref() that work everywhere instead of having to use QINCREF() / QDECREF() for QObject and qobject_incref() / qobject_decref() for its subtypes. The replacement is mechanical, except I broke a long line, and added a cast in monitor_qmp_cleanup_req_queue_locked(). Unlike qobject_decref(), qobject_unref() doesn't accept void *. Note that the new macros evaluate their argument exactly once, thus no need to shout them. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20180419150145.24795-4-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Rebased, semantic conflict resolved, commit message improved] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2018-03-02block: Switch passthrough drivers to .bdrv_co_block_status()Eric Blake
We are gradually moving away from sector-based interfaces, towards byte-based. Update the generic helpers, and all passthrough clients (blkdebug, commit, mirror, throttle) accordingly. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2018-02-09Move include qemu/option.h from qemu-common.h to actual usersMarkus Armbruster
qemu-common.h includes qemu/option.h, but most places that include the former don't actually need the latter. Drop the include, and add it to the places that actually need it. While there, drop superfluous includes of both headers, and separate #include from file comment with a blank line. This cleanup makes the number of objects depending on qemu/option.h drop from 4545 (out of 4743) to 284 in my "build everything" tree. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180201111846.21846-20-armbru@redhat.com> [Semantic conflict with commit bdd6a90a9e in block/nvme.c resolved]
2018-02-09Include qapi/qmp/qbool.h exactly where neededMarkus Armbruster
Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20180201111846.21846-15-armbru@redhat.com>
2017-10-26block: Align block status requestsEric Blake
Any device that has request_alignment greater than 512 should be unable to report status at a finer granularity; it may also be simpler for such devices to be guaranteed that the block layer has rounded things out to the granularity boundary (the way the block layer already rounds all other I/O out). Besides, getting the code correct for super-sector alignment also benefits us for the fact that our public interface now has byte granularity, even though none of our drivers have byte-level callbacks. Add an assertion in blkdebug that proves that the block layer never requests status of unaligned sections, similar to what it does on other requests (while still keeping the generic helper in place for when future patches add a throttle driver). Note that iotest 177 already covers this (it would fail if you use just the blkdebug.c hunk without the io.c changes). Meanwhile, we can drop assertions in callers that no longer have to pass in sector-aligned addresses. There is a mid-function scope added for 'count' and 'longret', for a couple of reasons: first, an upcoming patch will add an 'if' statement that checks whether a driver has an old- or new-style callback, and can conveniently use the same scope for less indentation churn at that time. Second, since we are trying to get rid of sector-based computations, wrapping things in a scope makes it easier to group and see what will be deleted in a final cleanup patch once all drivers have been converted to the new-style callback. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-10-09config: qemu_config_parse() return number of config groupsEduardo Habkost
Change qemu_config_parse() to return the number of config groups in success and -EINVAL on error. This will allow callers of qemu_config_parse() to check if something was really loaded from the config file. All existing callers of qemu_config_parse() and qemu_read_config_file() only check if the return value was negative, so the change shouldn't affect them. Reviewed-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Message-Id: <20171004025043.3788-2-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2017-09-04block: add default implementations for bdrv_co_get_block_status()Manos Pitsidianakis
bdrv_co_get_block_status_from_file() and bdrv_co_get_block_status_from_backing() set *file to bs->file and bs->backing respectively, so that bdrv_co_get_block_status() can recurse to them. Future block drivers won't have to duplicate code to implement this. Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-09-04block: remove bdrv_truncate callback in blkdebugManos Pitsidianakis
Now that bdrv_truncate is passed to bs->file by default, remove the callback from block/blkdebug.c and set is_filter to true. is_filter also gives access to other callbacks that are forwarded automatically to bs->file for filters. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-09-04qapi: Change data type of the FOO_lookup generated for enum FOOMarc-André Lureau
Currently, a FOO_lookup is an array of strings terminated by a NULL sentinel. A future patch will generate enums with "holes". NULL-termination will cease to work then. To prepare for that, store the length in the FOO_lookup by wrapping it in a struct and adding a member for the length. The sentinel will be dropped next. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20170822132255.23945-13-marcandre.lureau@redhat.com> [Basically redone] Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1503564371-26090-16-git-send-email-armbru@redhat.com> [Rebased]
2017-09-04qapi: Generate FOO_str() macro for QAPI enum FOOMarkus Armbruster
The next commit will put it to use. May look pointless now, but we're going to change the FOO_lookup's type, and then it'll help. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1503564371-26090-13-git-send-email-armbru@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
2017-09-04block: Use qemu_enum_parse() in blkdebug_debug_breakpoint()Marc-André Lureau
The error message on invalid blkdebug events changes from qemu-system-x86_64: LOCATION: Invalid event name "VALUE" to qemu-system-x86_64: LOCATION: invalid parameter value: VALUE Slight degradation, but the message is sub-par even before the patch. When complaining about a parameter value, both parameter name and value should be mentioned, as the value may well not be unique. Left for another day. Also left is the error message's unhelpful location: it points to the config=FILENAME rather than into that file. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20170822132255.23945-11-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [Rebased, commit message rewritten] Cc: Kevin Wolf <kwolf@redhat.com> Cc: Max Reitz <mreitz@redhat.com> Cc: qemu-block@nongnu.org Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1503564371-26090-8-git-send-email-armbru@redhat.com>
2017-07-11block: Add PreallocMode to bdrv_truncate()Max Reitz
For block drivers that just pass a truncate request to the underlying protocol, we can now pass the preallocation mode instead of aborting if it is not PREALLOC_MODE_OFF. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-3-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-11block: Add PreallocMode to BD.bdrv_truncate()Max Reitz
Add a PreallocMode parameter to the bdrv_truncate() function implemented by each block driver. Currently, we always pass PREALLOC_MODE_OFF and no driver accepts anything else. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20170613202107.10125-2-mreitz@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-07-10blkdebug: Support .bdrv_co_get_block_statusEric Blake
Without a passthrough status of BDRV_BLOCK_RAW, anything wrapped by blkdebug appears 100% allocated as data. Better is treating it the same as the underlying file being wrapped. Update iotest 177 for the new expected output. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-06-26blkdebug: Catch bs->exact_filename overflowMax Reitz
The bs->exact_filename field may not be sufficient to store the full blkdebug node filename. In this case, we should not generate a filename at all instead of an unusable one. Cc: qemu-stable@nongnu.org Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Message-id: 20170613172006.19685-2-mreitz@redhat.com Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-06-26block: change variable names in BlockDriverStateManos Pitsidianakis
Change the 'int count' parameter in *pwrite_zeros, *pdiscard related functions (and some others) to 'int bytes', as they both refer to bytes. This helps with code legibility. Signed-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr> Message-id: 20170609101808.13506-1-el13635@mail.ntua.gr Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-06-20qapi: merge QInt and QFloat in QNumMarc-André Lureau
We would like to use a same QObject type to represent numbers, whether they are int, uint, or floats. Getters will allow some compatibility between the various types if the number fits other representations. Add a few more tests while at it. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20170607163635.17635-7-marcandre.lureau@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> [parse_stats_intervals() simplified a bit, comment in test_visitor_in_int_overflow() tidied up, suppress bogus warnings] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-05-11blkdebug: Add ability to override unmap geometriesEric Blake
Make it easier to simulate various unusual hardware setups (for example, recent commits 3482b9b and b8d0a98 affect the Dell Equallogic iSCSI with its 15M preferred and maximum unmap and write zero sizing, or b2f95fe deals with the Linux loopback block device having a max_transfer of 64k), by allowing blkdebug to wrap any other device with further restrictions on various alignments. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-9-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11blkdebug: Simplify override logicEric Blake
Rather than store into a local variable, then copy to the struct if the value is valid, then reporting errors otherwise, it is simpler to just store into the struct and report errors if the value is invalid. This however requires that the struct store a 64-bit number, rather than a narrower type. Likewise, setting a sane errno value in ret prior to the sequence of parsing and jumping to out: on error makes it easier for the next patch to add a chain of similar checks. Signed-off-by: Eric Blake <eblake@redhat.com> Message-id: 20170429191419.30051-8-eblake@redhat.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11blkdebug: Add pass-through write_zero and discard supportEric Blake
In order to test the effects of artificial geometry constraints on operations like write zero or discard, we first need blkdebug to manage these actions. It also allows us to inject errors on those operations, just like we can for read/write/flush. We can also test the contract promised by the block layer; namely, if a device has specified limits on alignment or maximum size, then those limits must be obeyed (for now, the blkdebug driver merely inherits limits from whatever it is wrapping, but the next patch will further enhance it to allow specific limit overrides). This patch intentionally refuses to service requests smaller than the requested alignments; this is because an upcoming patch adds a qemu-iotest to prove that the block layer is correctly handling fragmentation, but the test only works if there is a way to tell the difference at artificial alignment boundaries when blkdebug is using a larger-than-default alignment. If we let the blkdebug layer always defer to the underlying layer, which potentially has a smaller granularity, the iotest will be thwarted. Tested by setting up an NBD server with export 'foo', then invoking: $ ./qemu-io qemu-io> open -o driver=blkdebug blkdebug::nbd://localhost:10809/foo qemu-io> d 0 15M qemu-io> w -z 0 15M Pre-patch, the server never sees the discard (it was silently eaten by the block layer); post-patch it is passed across the wire. Likewise, pre-patch the write is always passed with NBD_WRITE (with 15M of zeroes on the wire), while post-patch it can utilize NBD_WRITE_ZEROES (for less traffic). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-7-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11blkdebug: Refactor error injectionEric Blake
Rather than repeat the logic at each caller of checking if a Rule exists that warrants an error injection, fold that logic into inject_error(); and rename it to rule_check() for legibility. This will help the next patch, which adds two more callers that need to check rules for the potential of injecting errors. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-6-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2017-05-11blkdebug: Sanity check block layer guaranteesEric Blake
Commits 04ed95f4 and 1a62d0ac updated the block layer to auto-fragment any I/O to fit within device boundaries. Additionally, when using a minimum alignment of 4k, we want to ensure the block layer does proper read-modify-write rather than requesting I/O on a slice of a sector. Let's enforce that the contract is obeyed when using blkdebug. For now, blkdebug only allows alignment overrides, and just inherits other limits from whatever device it is wrapping, but a future patch will further enhance things. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20170429191419.30051-5-eblake@redhat.com Signed-off-by: Max Reitz <mreitz@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: 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: Do not unref bs->file on error in BD's openMax Reitz
The block layer takes care of removing the bs->file child if the block driver's bdrv_open()/bdrv_file_open() implementation fails. The block driver therefore does not need to do so, and indeed should not unless it sets bs->file to NULL afterwards -- because if this is not done, the bdrv_unref_child() in bdrv_open_inherit() will dereference the freed memory block at bs->file afterwards, which is not good. We can now decide whether to add a "bs->file = NULL;" after each of the offending bdrv_unref_child() invocations, or just drop them altogether. The latter is simpler, so let's do that. Cc: qemu-stable <qemu-stable@nongnu.org> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-02-28block: Request child permissions in filter driversKevin Wolf
All callers will have to request permissions for all of their child nodes. Block drivers that act as simply filters can use the default implementation of .bdrv_child_perm(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Acked-by: Fam Zheng <famz@redhat.com>
2017-02-24block: Pass BdrvChild to bdrv_truncate()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2017-02-21blkdebug: reschedule coroutine on the AioContext it is running onPaolo Bonzini
Keep the coroutine on the same AioContext. Without this change, there would be a race between yielding the coroutine and reentering it. While the race cannot happen now, because the code only runs from a single AioContext, this will change with multiqueue support in the block layer. While doing the change, replace custom bottom half with aio_co_schedule. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170213135235.12274-10-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-01-09blkdebug: Implement bdrv_co_preadv/pwritev/flushKevin Wolf
This enables byte granularity requests for blkdebug, and at the same time gets us rid of another user of the BDS-level AIO emulation. Note that unless align=512 is specified, this can behave subtly different from the old behaviour because bdrv_co_preadv/pwritev don't have to perform alignment adjustments any more. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2016-10-07block: use aio_bh_schedule_oneshotPaolo Bonzini
This simplifies bottom half handlers by removing calls to qemu_bh_delete and thus removing the need to stash the bottom half pointer in the opaque datum. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-08-15block/blkdebug: Store config filenameMax Reitz
Store the configuration file's filename so it can later be used in bdrv_refresh_filename() without having to directly access the options QDict which may contain a value of a non-string type. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>