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2014-10-20block: Split bdrv_new_root() off bdrv_new()Markus Armbruster
Creating an anonymous BDS can't fail. Make that obvious. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-14block/migration: Disable cache invalidate for incoming migrationAlexey Kardashevskiy
When migrated using libvirt with "--copy-storage-all", at the end of migration there is race between NBD mirroring task trying to do flush and migration completion, both end up invalidating cache. Since qcow2 driver does not handle this situation very well, random crashes happen. This disables the BDRV_O_INCOMING flag for the block device being migrated once the cache has been invalidated. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> -- fixed parens by hand Signed-off-by: Juan Quintela <quintela@redhat.com>
2014-10-03util: Emancipate id_wellformed() from QemuOptsMarkus Armbruster
IDs have long spread beyond QemuOpts: not everything with an ID necessarily goes through QemuOpts. Commit 9aebf3b is about such a case: block layer names are meant to be well-formed IDs, but some of them don't go through QemuOpts, and thus weren't checked. The commit fixed that the straightforward way: rename the internal QemuOpts helper id_wellformed() to qemu_opts_id_wellformed() and give it external linkage. Instead of using it directly in block.c, the commit adds wrapper bdrv_is_valid_name(), probably to hide the connection to QemuOpts. Go one logical step further: emancipate IDs from QemuOpts. Rename the function back to id_wellformed(), and put it in another file. While there, clean up its value to bool. Peel off the bdrv_is_valid_name() wrapper. [Replaced stray return 0 with return false to match bool returns used elsewhere in id_wellformed(). --Stefan] Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-25block: Validate node-nameKevin Wolf
The device_name of a BlockDriverState is currently checked because it is always used as a QemuOpts ID and qemu_opts_create() checks whether such IDs are wellformed. node-name is supposed to share the same namespace, but it isn't checked currently. This patch adds explicit checks both for device_name and node-name so that the same rules will still apply even if QemuOpts won't be used any more at some point. qemu-img used to use names with spaces in them, which isn't allowed any more. Replace them with underscores. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-25block: Improve message for device name clashing with node nameMarkus Armbruster
Suggested-by: Benoit Canet <benoit.canet@nodalink.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-25block: Keep DriveInfo alive until BlockDriverState diesMarkus Armbruster
If the BDS's refcnt > 0, drive_del() destroys the DriveInfo, but not the BDS. This can happen in three places: * Device model destruction during unplug: blockdev_auto_del() * Xen IDE unplug: pci_piix3_xen_ide_unplug() * drive_del command when no device model is attached: do_drive_del() The other callers of drive_del are on error paths where refcnt == 1. If the user somehow manages to plug in a device model using a BDS that has gone through drive_del(), the legacy configuration passed in DriveInfo doesn't reach the device model, and automatic deletion on unplug doesn't work. Worse, some device models such as scsi-disk crash when DriveInfo doesn't exist. This is theoretical; I didn't research an actual reproducer. The problem was introduced when we replaced DriveInfo reference counting by BDS reference counting in commit a94a3fa..fa510eb. Fix by keeping DriveInfo alive until its BDS dies. This affects qemu_drive_opts: now you can't reuse the same ID for new drive options until the BDS dies. Before, you could, but since the code always attempts to create a BDS with the same ID next, the enclosing operation "create a new drive" failed anyway. Different error path, same result. Unfortunately, the fix involves use of blockdev.c stuff from block.c, which is a layering violation. Fortunately, my forthcoming BlockBackend work will get rid of it again. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-22block: Rename qemu_aio_release -> qemu_aio_unrefFam Zheng
Suggested-by: Benoît Canet <benoit.canet@irqsave.net> Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22block: Drop AIOCBInfo.cancelFam Zheng
Now that all the implementations are converted to asynchronous version and we can emulate synchronous cancellation with it. Let's drop the unused member. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22block: Drop bdrv_em_aiocb_info.cancelFam Zheng
Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22block: Drop bdrv_em_co_aiocb_info.cancelFam Zheng
Also drop the now unused ->done pointer. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22block: Add bdrv_aio_cancel_asyncFam Zheng
This is the async version of bdrv_aio_cancel, which doesn't block the caller. It guarantees that the cb is called either before returning or some time later. bdrv_aio_cancel can base on bdrv_aio_cancel_async, later we can convert all .io_cancel implementations to .io_cancel_async, and the aio_poll is the common logic. In the end, .io_cancel can be dropped. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22block: Add refcnt in BlockDriverAIOCBFam Zheng
This will be useful in synchronous cancel emulation with bdrv_aio_cancel_async. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-11block: extend BLOCK_IO_ERROR with reason stringLuiz Capitulino
BLOCK_IO_ERROR events are logged by libvirt, which helps with post mortem analysis of guests. However, one information that we miss today is a human readable string describing the cause of the I/O error. This commit adds that string it to BLOCK_IO_ERROR. Note that this string is a debugging aid for humans, meaning that it should not parsed by applications. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10block: Make the block accounting functions operate on BlockAcctStatsBenoît Canet
This is the next step for decoupling block accounting functions from BlockDriverState. In a future commit the BlockAcctStats structure will be moved from BlockDriverState to the device models structures. Note that bdrv_get_stats was introduced so device models can retrieve the BlockAcctStats structure of a BlockDriverState without being aware of it's layout. This function should go away when BlockAcctStats will be embedded in the device models structures. CC: Kevin Wolf <kwolf@redhat.com> CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Keith Busch <keith.busch@intel.com> CC: Anthony Liguori <aliguori@amazon.com> CC: "Michael S. Tsirkin" <mst@redhat.com> CC: Paolo Bonzini <pbonzini@redhat.com> CC: Eric Blake <eblake@redhat.com> CC: Peter Maydell <peter.maydell@linaro.org> CC: Michael Tokarev <mjt@tls.msk.ru> CC: John Snow <jsnow@redhat.com> CC: Markus Armbruster <armbru@redhat.com> CC: Alexander Graf <agraf@suse.de> CC: Max Reitz <mreitz@redhat.com> Signed-off-by: Benoît Canet <benoit.canet@nodalink.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10block: Extract the block accounting codeBenoît Canet
The plan is to add new accounting metrics (latency, invalid requests, failed requests, queue depth) and block.c is overpopulated so it will be better to work in a separate module. Moreover the long term plan is to have statistics in each of the BDS of the graph for metrology purpose; this means that the device model statistics must move from the topmost BDS to the device model. So we need to decouple the statistic code from BlockDriverState. This is another argument for the extraction of the code in a separate module. CC: Kevin Wolf <kwolf@redhat.com> CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Max Reitz <mreitz@redhat.com> CC: Eric Blake <eblake@redhat.com> CC: Benoit Canet <benoit@irqsave.net> CC: Fam Zheng <famz@redhat.com> CC: Peter Crosthwaite <peter.crosthwaite@xilinx.com> CC: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Benoît Canet <benoit.canet@nodalink.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10block: Extract the BlockAcctStats structureBenoît Canet
Extract the block accounting statistics into a structure so the block device models can hold them in the future. CC: Kevin Wolf <kwolf@redhat.com> CC: Stefan Hajnoczi <stefanha@redhat.com> CC: Max Reitz <mreitz@redhat.com> CC: Eric Blake <eblake@redhat.com> Signed-off-by: Benoît Canet <benoit.canet@nodalink.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-10block: extend BLOCK_IO_ERROR event with nospace indicatorLuiz Capitulino
Management software, such as RHEV's vdsm, want to be able to allocate disk space on demand. The basic use case is to start a VM with a small disk and then the disk is enlarged when QEMU hits a ENOSPC condition. To this end, the management software has to be notified when QEMU encounters ENOSPC. The solution implemented by this commit is simple: it extends the BLOCK_IO_ERROR with a 'nospace' key, which is true when QEMU is stopped due to ENOSPC. Note that support for querying this event is already present in query-block by means of the 'io-status' key. Also, the new 'nospace' BLOCK_IO_ERROR field shares the same semantics with 'io-status', which basically means that werror= has to be set to either 'stop' or 'enospc' to enable 'nospace'. Finally, this commit also updates the 'io-status' key doc in the schema with a list of supported device models. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-08block: kill tail whitespace in block.cLiu Yuan
Cc: Kevin Wolf <kwolf@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Liu Yuan <namei.unix@gmail.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-29block: fix overlapping multiwrite requestsStefan Hajnoczi
When request A is a strict superset of request B: AAAAAAAA BBBB multiwrite_merge() merges them as follows: AABBBB The tail of request A should have been included: AABBBBAA This patch fixes data loss but this code path is probably rare. Since guests cannot assume ordering between in-flight requests, few applications submit overlapping write requests. Reported-by: Slava Pestov <sviatoslav.pestov@gmail.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-29block: Add AIO context notifiersMax Reitz
If a long-running operation on a BDS wants to always remain in the same AIO context, it somehow needs to keep track of the BDS changing its context. This adds a function for registering callbacks on a BDS which are called whenever the BDS is attached or detached from an AIO context. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-28block: sort formats alphabetically in bdrv_iterate_format()Stefan Hajnoczi
Format names are best consumed in alphabetical order. This makes human-readable output easy to produce. bdrv_iterate_format() already has an array of format strings. Sort them before invoking the iteration callback. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Benoît Canet <benoit.canet@nodalink.com>
2014-08-20block: Add bdrv_refresh_filename()Max Reitz
Some block devices may not have a filename in their BDS; and for some, there may not even be a normal filename at all. To work around this, add a function which tries to construct a valid filename for the BDS.filename field. If a filename exists or a block driver is able to reconstruct a valid filename (which is placed in BDS.exact_filename), this can directly be used. If no filename can be constructed, we can still construct an options QDict which is then converted to a JSON object and prefixed with the "json:" pseudo protocol prefix. The QDict is placed in BDS.full_open_options. For most block drivers, this process can be done automatically; those that need special handling may define a .bdrv_refresh_filename() method to fill BDS.exact_filename and BDS.full_open_options themselves. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-20block: Use g_new() & friends where that makes obvious senseMarkus Armbruster
g_new(T, n) is neater than g_malloc(sizeof(T) * n). It's also safer, for two reasons. One, it catches multiplication overflowing size_t. Two, it returns T * rather than void *, which lets the compiler catch more type errors. Patch created with Coccinelle, with two manual changes on top: * Add const to bdrv_iterate_format() to keep the types straight * Convert the allocation in bdrv_drop_intermediate(), which Coccinelle inexplicably misses Coccinelle semantic patch: @@ type T; @@ -g_malloc(sizeof(T)) +g_new(T, 1) @@ type T; @@ -g_try_malloc(sizeof(T)) +g_try_new(T, 1) @@ type T; @@ -g_malloc0(sizeof(T)) +g_new0(T, 1) @@ type T; @@ -g_try_malloc0(sizeof(T)) +g_try_new0(T, 1) @@ type T; expression n; @@ -g_malloc(sizeof(T) * (n)) +g_new(T, n) @@ type T; expression n; @@ -g_try_malloc(sizeof(T) * (n)) +g_try_new(T, n) @@ type T; expression n; @@ -g_malloc0(sizeof(T) * (n)) +g_new0(T, n) @@ type T; expression n; @@ -g_try_malloc0(sizeof(T) * (n)) +g_try_new0(T, n) @@ type T; expression p, n; @@ -g_realloc(p, sizeof(T) * (n)) +g_renew(T, p, n) @@ type T; expression p, n; @@ -g_try_realloc(p, sizeof(T) * (n)) +g_try_renew(T, p, n) Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block: Catch !bs->drv in bdrv_check()Max Reitz
qemu-img check calls bdrv_check() twice if the first run repaired some inconsistencies. If the first run however again triggered corruption prevention (on qcow2) due to very bad inconsistencies, bs->drv may be NULL afterwards. Thus, bdrv_check() should check whether bs->drv is set. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block: Handle failure for potentially large allocationsKevin Wolf
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses bounce buffer allocations in block.c. While at it, convert bdrv_commit() from plain g_malloc() to qemu_try_blockalign(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Introduce qemu_try_blockalign()Kevin Wolf
This function returns NULL instead of aborting when an allocation fails. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15block: allow bdrv_unref() to be passed NULL pointersJeff Cody
If bdrv_unref() is passed a NULL BDS pointer, it is safe to exit with no operation. This will allow cleanup code to blindly call bdrv_unref() on a BDS that has been initialized to NULL. Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15block: bump coroutine pool size for drivesStefan Hajnoczi
When a BlockDriverState is associated with a storage controller DeviceState we expect guest I/O. Use this opportunity to bump the coroutine pool size by 64. This patch ensures that the coroutine pool size scales with the number of drives attached to the guest. It should increase coroutine pool usage (which makes qemu_coroutine_create() fast) without hogging too much memory when fewer drives are attached. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-08-15block: Avoid bdrv_get_geometry() where errors should be detectedMarkus Armbruster
bdrv_get_geometry() hides errors. Use bdrv_nb_sectors() or bdrv_getlength() instead where that's obviously inappropriate. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Drop superfluous aligning of bdrv_getlength()'s valueMarkus Armbruster
It returns a multiple of the sector size. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Use bdrv_nb_sectors() where sectors, not bytes are wantedMarkus Armbruster
Instead of bdrv_getlength(). Aside: a few of these callers don't handle errors. I didn't investigate whether they should. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Use bdrv_nb_sectors() in bdrv_co_get_block_status()Markus Armbruster
Instead of bdrv_getlength(). Replace variables length, length2 by total_sectors, nb_sectors2. Bonus: use total_sectors instead of the slightly unclean bs->total_sectors. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Use bdrv_nb_sectors() in bdrv_aligned_preadv()Markus Armbruster
Instead of bdrv_getlength(). Eliminate variable len. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: Use bdrv_nb_sectors() in bdrv_make_zero()Markus Armbruster
Instead of bdrv_getlength(). Variable target_size is initially in bytes, then changes meaning to sectors. Ugh. Replace by target_sectors. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15block: New bdrv_nb_sectors()Markus Armbruster
A call to retrieve the image size converts between bytes and sectors several times: * BlockDriver method bdrv_getlength() returns bytes. * refresh_total_sectors() converts to sectors, rounding up, and stores in total_sectors. * bdrv_getlength() converts total_sectors back to bytes (now rounded up to a multiple of the sector size). * Callers wanting sectors rather bytes convert it right back. Example: bdrv_get_geometry(). bdrv_nb_sectors() provides a way to omit the last two conversions. It's exactly bdrv_getlength() with the conversion to bytes omitted. It's functionally like bdrv_get_geometry() without its odd error handling. Reimplement bdrv_getlength() and bdrv_get_geometry() on top of bdrv_nb_sectors(). The next patches will convert some users of bdrv_getlength() to bdrv_nb_sectors(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-18block: Add Error argument to bdrv_refresh_limits()Kevin Wolf
Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-14block: Assert qiov length matches request lengthKevin Wolf
At least raw-posix relies on this because it can allocate bounce buffers based on the request length, but access it using all of the qiov entries later. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-07-14block: Make qiov match the request size until EOFKevin Wolf
If a read request goes across EOF, the block driver sees a shortened request that stops at EOF (the rest is memsetted in block.c), however the original qiov was used for this request. This patch makes the qiov size match the request size, avoiding a potential buffer overflow in raw-posix. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2014-07-09block: prefer aio_poll to qemu_aio_waitPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-09block: Fix bdrv_is_allocated() return valueKevin Wolf
bdrv_is_allocated() should return either 0 or 1 in successful cases. We're lucky that currently, the callers that rely on this (e.g. because they check for ret == 1) don't seem to break badly. They just might skip some optimisation or in the case of qemu-io 'map' print separate lines where a single line would suffice. In theory, a wrong allocation status could lead to image corruption with certain operations, so let's fix this quickly. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-07-07block: block: introduce APIs for submitting IO as a batchMing Lei
This patch introduces three APIs so that following patches can support queuing I/O requests and submitting them as a batch for improving I/O performance. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01block: extend block-commit to accept a string for the backing fileJeff Cody
On some image chains, QEMU may not always be able to resolve the filenames properly, when updating the backing file of an image after a block commit. For instance, certain relative pathnames may fail, or drives may have been specified originally by file descriptor (e.g. /dev/fd/???), or a relative protocol pathname may have been used. In these instances, QEMU may lack the information to be able to make the correct choice, but the user or management layer most likely does have that knowledge. With this extension to the block-commit api, the user is able to change the backing file of the overlay image as part of the block-commit operation. This allows the change to be 'safe', in the sense that if the attempt to write the overlay image metadata fails, then the block-commit operation returns failure, without disrupting the guest. If the commit top is the active layer, then specifying the backing file string will be treated as an error (there is no overlay image to modify in that case). If a backing file string is not specified in the command, the backing file string to use is determined in the same manner as it was previously. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01block: add helper function to determine if a BDS is in a chainJeff Cody
This is a small helper function, to determine if 'base' is in the chain of BlockDriverState 'top'. It returns true if it is in the chain, and false otherwise. If either argument is NULL, it will also return false. Reviewed-by: Benoit Canet <benoit@irqsave.net> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01block: simplify bdrv_find_base() and bdrv_find_overlay()Jeff Cody
This simplifies the function bdrv_find_overlay(). With this change, bdrv_find_base() is just a subset of usage of bdrv_find_overlay(), so this also takes advantage of that. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-27block.c: Don't return success for bdrv_append_temp_snapshot() failureChen Gang
When failure occurs, 'ret' need be set, or may return 0 to indicate success. Previously, an error was set in errp, but 0 was returned anyway. So let bdrv_append_temp_snapshot() return an error code and use that for the bdrv_open() return value. Also, error_propagate() need be called only one time within a function. Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27block: Add replaces argument to drive-mirrorBenoît Canet
drive-mirror will bdrv_swap the new BDS named node-name with the one pointed by replaces when the mirroring is finished. Signed-off-by: Benoit Canet <benoit@irqsave.net> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27block: check for RESIZE blocker in the QMP command, not bdrv_truncate()Jeff Cody
If we check for the RESIZE blocker in bdrv_truncate(), that means a commit will fail if the overlay layer is larger than the base, due to the backing blocker. This is a regression in behavior from 2.0; currently, commit will try to grow the size of the base image to match the overlay size, if the overlay size is larger. By moving this into the QMP command qmp_block_resize(), it allows usage of bdrv_truncate() within block jobs. Signed-off-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-26block: Remove a special case for protocolsKevin Wolf
The only semantic change is that bs->open_flags gets BDRV_O_PROTOCOL set now. This isn't useful, but it doesn't hurt either. The code that was previously skipped by 'goto done' is automatically disabled because protocol drivers don't support backing files (and if they did, this would probably be a fix) and can't have snapshot_flags set. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26block: Catch backing files assigned to non-COW driversKevin Wolf
Since we parse backing.* options to add a backing file from the command line when the driver didn't assign one, it has been possible to have a backing file for e.g. raw images (it just was never accessed). This is obvious nonsense and should be rejected. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2014-06-26block: Remove second bdrv_open() recursionKevin Wolf
This recursion was introduced in commit 505d7583 in order to allow nesting image formats. It only ever takes effect when the user explicitly specifies a driver name and that driver isn't suitable for the protocol level. We can check this earlier in bdrv_open() and if the explicitly requested driver is a format driver, clear BDRV_O_PROTOCOL so that another bs->file layer is opened. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>