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2020-09-23qemu/atomic.h: rename atomic_ to qatomic_Stefan Hajnoczi
clang's C11 atomic_fetch_*() functions only take a C11 atomic type pointer argument. QEMU uses direct types (int, etc) and this causes a compiler error when a QEMU code calls these functions in a source file that also included <stdatomic.h> via a system header file: $ CC=clang CXX=clang++ ./configure ... && make ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid) Avoid using atomic_*() names in QEMU's atomic.h since that namespace is used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h and <stdatomic.h> can co-exist. I checked /usr/include on my machine and searched GitHub for existing "qatomic_" users but there seem to be none. This patch was generated using: $ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \ sort -u >/tmp/changed_identifiers $ for identifier in $(</tmp/changed_identifiers); do sed -i "s%\<$identifier\>%q$identifier%g" \ $(git grep -I -l "\<$identifier\>") done I manually fixed line-wrap issues and misaligned rST tables. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
2020-09-17qemu/: fix some comment spelling errorszhaolichang
I found that there are many spelling errors in the comments of qemu, so I used the spellcheck tool to check the spelling errors and finally found some spelling errors in the folder. Signed-off-by: zhaolichang <zhaolichang@huawei.com> Reviewed-by: Alex Bennee <alex.bennee@linaro.org> Message-Id: <20200917075029.313-2-zhaolichang@huawei.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2020-09-07block: Leave BDS.backing_{file,format} constantMax Reitz
Parts of the block layer treat BDS.backing_file as if it were whatever the image header says (i.e., if it is a relative path, it is relative to the overlay), other parts treat it like a cache for bs->backing->bs->filename (relative paths are relative to the CWD). Considering bs->backing->bs->filename exists, let us make it mean the former. Among other things, this now allows the user to specify a base when using qemu-img to commit an image file in a directory that is not the CWD (assuming, everything uses relative filenames). Before this patch: $ ./qemu-img create -f qcow2 foo/bot.qcow2 1M $ ./qemu-img create -f qcow2 -b bot.qcow2 foo/mid.qcow2 $ ./qemu-img create -f qcow2 -b mid.qcow2 foo/top.qcow2 $ ./qemu-img commit -b mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'mid.qcow2' in the backing chain of 'foo/top.qcow2' $ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.qcow2' $ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find '[...]/foo/mid.qcow2' in the backing chain of 'foo/top.qcow2' After this patch: $ ./qemu-img commit -b mid.qcow2 foo/top.qcow2 Image committed. $ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.qcow2' $ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2 Image committed. With this change, bdrv_find_backing_image() must look at whether the user has overridden a BDS's backing file. If so, it can no longer use bs->backing_file, but must instead compare the given filename against the backing node's filename directly. Note that this changes the QAPI output for a node's backing_file. We had very inconsistent output there (sometimes what the image header said, sometimes the actual filename of the backing image). This inconsistent output was effectively useless, so we have to decide one way or the other. Considering that bs->backing_file usually at runtime contained the path to the image relative to qemu's CWD (or absolute), this patch changes QAPI's backing_file to always report the bs->backing->bs->filename from now on. If you want to receive the image header information, you have to refer to full-backing-filename. This necessitates a change to iotest 228. The interesting information it really wanted is the image header, and it can get that now, but it has to use full-backing-filename instead of backing_file. Because of this patch's changes to bs->backing_file's behavior, we also need some reference output changes. Along with the changes to bs->backing_file, stop updating BDS.backing_format in bdrv_backing_attach() as well. This way, ImageInfo's backing-filename and backing-filename-format fields will represent what the image header says and nothing else. iotest 245 changes in behavior: With the backing node no longer overriding the parent node's backing_file string, you can now omit the @backing option when reopening a node with neither a default nor a current backing file even if it used to have a backing node at some point. 273 also changes: The base image is opened without a format layer, so ImageInfo.backing-filename-format used to report "file" for the base image's overlay after blockdev-snapshot. However, the image header never says "file" anywhere, so it now reports $IMGFMT. Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-07block: Improve get_allocated_file_size's defaultMax Reitz
There are two practical problems with bdrv_get_allocated_file_size()'s default right now: (1) For drivers with children, we should generally sum all their sizes instead of just passing the request through to bs->file. The latter is good for filters, but not so much for format drivers. (2) Filters need not have bs->file, so we should actually go to the filtered child instead of hard-coding bs->file. Fix this by splitting the default implementation into three branches: (1) For filter drivers: Return the size of the filtered child (2) For protocol drivers: Return -ENOTSUP, because the default implementation cannot make a guess (3) For other drivers: Sum all data-bearing children's sizes Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-07block: Use CAFs for debug breakpointsMax Reitz
When looking for a blkdebug node (which implements debug breakpoints), use bdrv_primary_bs() to iterate through the graph, because that is where a blkdebug node would be. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: Use CAFs in bdrv_refresh_filename()Max Reitz
bdrv_refresh_filename() and the kind of related bdrv_dirname() should look to the primary child when they wish to copy the underlying file's filename. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: Re-evaluate backing file handling in reopenMax Reitz
Reopening a node's backing child needs a bit of special handling because the "backing" child has different defaults than all other children (among other things). Adding filter support here is a bit more difficult than just using the child access functions. In fact, we often have to directly use bs->backing because these functions are about the "backing" child (which may or may not be the COW backing file). Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-07block: Use CAFs when working with backing chainsMax Reitz
Use child access functions when iterating through backing chains so filters do not break the chain. In addition, bdrv_find_overlay() will now always return the actual overlay; that is, it will never return a filter node but only one with a COW backing file (there may be filter nodes between that node and @bs). Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-07block: Use bdrv_filter_(bs|child) where obviousMax Reitz
Places that use patterns like if (bs->drv->is_filter && bs->file) { ... something about bs->file->bs ... } should be BlockDriverState *filtered = bdrv_filter_bs(bs); if (filtered) { ... something about @filtered ... } instead. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: Add bdrv_supports_compressed_writes()Max Reitz
Filters cannot compress data themselves but they have to implement .bdrv_co_pwritev_compressed() still (or they cannot forward compressed writes). Therefore, checking whether bs->drv->bdrv_co_pwritev_compressed is non-NULL is not sufficient to know whether the node can actually handle compressed writes. This function looks down the filter chain to see whether there is a non-filter that can actually convert the compressed writes into compressed data (and thus normal writes). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: Drop bdrv_is_encrypted()Max Reitz
The original purpose of bdrv_is_encrypted() was to inquire whether a BDS can be used without the user entering a password or not. It has not been used for that purpose for quite some time. Actually, it is not even fit for that purpose, because to answer that question, it would have recursively query all of the given node's children. So now we have to decide in which direction we want to fix bdrv_is_encrypted(): Recursively query all children, or drop it and just use bs->encrypted to get the current node's status? Nowadays, its only purpose is to report through bdrv_query_image_info() whether the given image is encrypted or not. For this purpose, it is probably more interesting to see whether a given node itself is encrypted or not (otherwise, a management application cannot discern for certain which nodes are really encrypted and which just have encrypted children). Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: Include filters when freezing backing chainMax Reitz
In order to make filters work in backing chains, the associated functions must be able to deal with them and freeze both COW and filter child links. While at it, add some comments that note which functions require their caller to ensure that a given child link is not frozen, and how the callers do so. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: bdrv_set_backing_hd() is about bs->backingMax Reitz
bdrv_set_backing_hd() is a function that explicitly cares about the bs->backing child. Highlight that in its description and use child_bs(bs->backing) instead of backing_bs(bs) to make it more obvious. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: bdrv_cow_child() for bdrv_has_zero_init()Max Reitz
bdrv_has_zero_init() should use bdrv_cow_child() if it wants to check whether the given BDS has a COW backing file. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2020-09-07block: Add chain helper functionsMax Reitz
Add some helper functions for skipping filters in a chain of block nodes. Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-09-07block: Add child access functionsMax Reitz
There are BDS children that the general block layer code can access, namely bs->file and bs->backing. Since the introduction of filters and external data files, their meaning is not quite clear. bs->backing can be a COW source, or it can be a filtered child; bs->file can be a filtered child, it can be data and metadata storage, or it can be just metadata storage. This overloading really is not helpful. This patch adds functions that retrieve the correct child for each exact purpose. Later patches in this series will make use of them. Doing so will allow us to handle filter nodes in a meaningful way. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2020-09-07block: Raise an error when backing file parameter is an empty stringConnor Kuehl
Providing an empty string for the backing file parameter like so: qemu-img create -f qcow2 -b '' /tmp/foo allows the flow of control to reach and subsequently fail an assert statement because passing an empty string to bdrv_get_full_backing_filename_from_filename() simply results in NULL being returned without an error being raised. To fix this, let's check for an empty string when getting the value from the opts list. Reported-by: Attila Fazekas <afazekas@redhat.com> Fixes: https://bugzilla.redhat.com/1809553 Signed-off-by: Connor Kuehl <ckuehl@redhat.com> Message-Id: <20200813134722.802180-1-ckuehl@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-08-21meson: replace create-config with meson configure_filePaolo Bonzini
Move the create-config logic to meson.build; create a configuration_data object and let meson handle the quoting and output. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-08-21meson: convert blockMarc-André Lureau
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-17block: Require aligned image size to avoid assertion failureKevin Wolf
Unaligned requests will automatically be aligned to bl.request_alignment and we can't extend write requests to access space beyond the end of the image without resizing the image, so if we have the WRITE permission, but not the RESIZE one, it's required that the image size is aligned. Failing to meet this requirement could cause assertion failures like this if RESIZE permissions weren't requested: qemu-img: block/io.c:1910: bdrv_co_write_req_prepare: Assertion `end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE' failed. This was e.g. triggered by qemu-img converting to a target image with 4k request alignment when the image was only aligned to 512 bytes, but not to 4k. Turn this into a graceful error in bdrv_check_perm() so that WRITE without RESIZE can only be taken if the image size is aligned. If a user holds both permissions and drops only RESIZE, the function will return an error, but bdrv_child_try_set_perm() will ignore the failure silently if permissions are only requested to be relaxed and just keep both permissions while returning success. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20200716142601.111237-2-kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-14qemu-img: Deprecate use of -b without -FEric Blake
Creating an image that requires format probing of the backing image is potentially unsafe (we've had several CVEs over the years based on probes leaking information to the guest on a subsequent boot, although these days tools like libvirt are aware of the issue enough to prevent the worst effects). For example, if our probing algorithm ever changes, or if other tools like libvirt determine a different probe result than we do, then subsequent use of that backing file under a different format will present corrupted data to the guest. Fortunately, the worst effects occur only when the backing image is originally raw, and we at least prevent commit into a probed raw backing file that would change its probed type. Still, it is worth starting a deprecation clock so that future qemu-img can refuse to create backing chains that would rely on probing, to encourage clients to avoid unsafe practices. Most warnings are intentionally emitted from bdrv_img_create() in the block layer, but qemu-img convert uses bdrv_create() which cannot emit its own warning without causing spurious warnings on other code paths. In the end, all command-line image creation or backing file rewriting now performs a check. Furthermore, if we probe a backing file as non-raw, then it is safe to explicitly record that result (rather than relying on future probes); only where we probe a raw image do we care about further warnings to the user when using such an image (for example, commits into a probed-raw backing file are prevented), to help them improve their tooling. But whether or not we make the probe results explicit, we still warn the user to remind them to upgrade their workflow to supply -F always. iotest 114 specifically wants to create an unsafe image for later amendment rather than defaulting to our new default of recording a probed format, so it needs an update. While touching it, expand it to cover all of the various warnings enabled by this patch. iotest 301 also shows a change to qcow messages. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200706203954.341758-11-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-14block: Add support to warn on backing file change without formatEric Blake
For now, this is a mechanical addition; all callers pass false. But the next patch will use it to improve 'qemu-img rebase -u' when selecting a backing file with no format. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Ján Tomko <jtomko@redhat.com> Message-Id: <20200706203954.341758-10-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-14block: Error if backing file fails during creation without -uEric Blake
Back in commit 6e6e55f5 (Jul 2017, v2.10), we tweaked the code to warn if the backing file could not be opened but the user gave a size, unless the user also passes the -u option to bypass the open of the backing file. As one common reason for failure to open the backing file is when there is mismatch in the requested backing format in relation to what the backing file actually contains, we actually want to open the backing file and ensure that it has the right format in as many cases as possible. iotest 301 for qcow demonstrates how detecting explicit format mismatch is useful to prevent the creation of an image that would probe differently than the user requested. Now is the time to finally turn the warning an error, as promised. Note that the original warning was added prior to our documentation of an official deprecation policy (eb22aeca, also Jul 2017), and because the warning didn't mention the word "deprecated", we never actually remembered to document it as such. But the warning has been around long enough that I don't see prolonging it another two releases. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200706203954.341758-7-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-14qemu-img: Flush stdout before before potential stderr messagesEric Blake
During 'qemu-img create ... 2>&1', if --quiet is not in force, we can end up with buffered I/O in stdout that was produced before failure, but which appears in output after failure. This is confusing; the fix is to flush stdout prior to attempting anything that might produce an error message. Several iotests demonstrate the resulting ordering change now that the merged outputs now reflect chronology. (An even better fix would be to avoid printf from within block.c altogether, but that's much more invasive...) Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20200706203954.341758-2-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-07-10error: Reduce unnecessary error propagationMarkus Armbruster
When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away, even when we need to keep error_propagate() for other error paths. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-38-armbru@redhat.com>
2020-07-10error: Eliminate error_propagate() with Coccinelle, part 2Markus Armbruster
When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away. The previous commit did that with a Coccinelle script I consider fairly trustworthy. This commit uses the same script with the matching of return taken out, i.e. we convert if (!foo(..., &err)) { ... error_propagate(errp, err); ... } to if (!foo(..., errp)) { ... ... } This is unsound: @err could still be read between afterwards. I don't know how to express "no read of @err without an intervening write" in Coccinelle. Instead, I manually double-checked for uses of @err. Suboptimal line breaks tweaked manually. qdev_realize() simplified further to placate scripts/checkpatch.pl. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-36-armbru@redhat.com>
2020-07-10error: Eliminate error_propagate() with Coccinelle, part 1Markus Armbruster
When all we do with an Error we receive into a local variable is propagating to somewhere else, we can just as well receive it there right away. Convert if (!foo(..., &err)) { ... error_propagate(errp, err); ... return ... } to if (!foo(..., errp)) { ... ... return ... } where nothing else needs @err. Coccinelle script: @rule1 forall@ identifier fun, err, errp, lbl; expression list args, args2; binary operator op; constant c1, c2; symbol false; @@ if ( ( - fun(args, &err, args2) + fun(args, errp, args2) | - !fun(args, &err, args2) + !fun(args, errp, args2) | - fun(args, &err, args2) op c1 + fun(args, errp, args2) op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; ) } @rule2 forall@ identifier fun, err, errp, lbl; expression list args, args2; expression var; binary operator op; constant c1, c2; symbol false; @@ - var = fun(args, &err, args2); + var = fun(args, errp, args2); ... when != err if ( ( var | !var | var op c1 ) ) { ... when != err when != lbl: when strict - error_propagate(errp, err); ... when != err ( return; | return c2; | return false; | return var; ) } @depends on rule1 || rule2@ identifier err; @@ - Error *err = NULL; ... when != err Not exactly elegant, I'm afraid. The "when != lbl:" is necessary to avoid transforming if (fun(args, &err)) { goto out } ... out: error_propagate(errp, err); even though other paths to label out still need the error_propagate(). For an actual example, see sclp_realize(). Without the "when strict", Coccinelle transforms vfio_msix_setup(), incorrectly. I don't know what exactly "when strict" does, only that it helps here. The match of return is narrower than what I want, but I can't figure out how to express "return where the operand doesn't use @err". For an example where it's too narrow, see vfio_intx_enable(). Silently fails to convert hw/arm/armsse.c, because Coccinelle gets confused by ARMSSE being used both as typedef and function-like macro there. Converted manually. Line breaks tidied up manually. One nested declaration of @local_err deleted manually. Preexisting unwanted blank line dropped in hw/riscv/sifive_e.c. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200707160613.848843-35-armbru@redhat.com>
2020-07-10block: Avoid error accumulation in bdrv_img_create()Markus Armbruster
When creating an image fails because the format doesn't support option "backing_file" or "backing_fmt", bdrv_img_create() first has qemu_opt_set() put a generic error into @local_err, then puts the real error into @errp with error_setg(), and then propagates the former to the latter, which throws away the generic error. A bit complicated, but works. Now that qemu_opt_set() returns a useful value, we can simply ignore the generic error instead. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20200707160613.848843-16-armbru@redhat.com>
2020-07-10qemu-option: Use returned bool to check for failureMarkus Armbruster
The previous commit enables conversion of foo(..., &err); if (err) { ... } to if (!foo(..., &err)) { ... } for QemuOpts functions that now return true / false on success / error. Coccinelle script: @@ identifier fun = { opts_do_parse, parse_option_bool, parse_option_number, parse_option_size, qemu_opt_parse, qemu_opt_rename, qemu_opt_set, qemu_opt_set_bool, qemu_opt_set_number, qemu_opts_absorb_qdict, qemu_opts_do_parse, qemu_opts_from_qdict_entry, qemu_opts_set, qemu_opts_validate }; expression list args, args2; typedef Error; Error *err; @@ - fun(args, &err, args2); - if (err) + if (!fun(args, &err, args2)) { ... } A few line breaks tidied up manually. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20200707160613.848843-15-armbru@redhat.com> [Conflict with commit 0b6786a9c1 "block/amend: refactor qcow2 amend options" resolved by rerunning Coccinelle on master's version]
2020-07-06block: inline bdrv_unallocated_blocks_are_zero()Vladimir Sementsov-Ogievskiy
The function has only one user: bdrv_co_block_status(). Inline it to simplify reviewing of the following patches, which will finally drop unallocated_blocks_are_zero field too. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200528094405.145708-3-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06block/amend: add 'force' optionMaxim Levitsky
'force' option will be used for some unsafe amend operations. This includes things like erasing last keyslot in luks based formats (which destroys the data, unless the master key is backed up by external means), but that _might_ be desired result. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200608094030.670121-4-mlevitsk@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-06-10block: Call attention to truncation of long NBD exportsEric Blake
Commit 93676c88 relaxed our NBD client code to request export names up to the NBD protocol maximum of 4096 bytes without NUL terminator, even though the block layer can't store anything longer than 4096 bytes including NUL terminator for display to the user. Since this means there are some export names where we have to truncate things, we can at least try to make the truncation a bit more obvious for the user. Note that in spite of the truncated display name, we can still communicate with an NBD server using such a long export name; this was deemed nicer than refusing to even connect to such a server (since the server may not be under our control, and since determining our actual length limits gets tricky when nbd://host:port/export and nbd+unix:///export?socket=/path are themselves variable-length expansions beyond the export name but count towards the block layer name length). Reported-by: Xueqiang Wei <xuwei@redhat.com> Fixes: https://bugzilla.redhat.com/1843684 Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20200610163741.3745251-3-eblake@redhat.com>
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: Drop child_fileMax Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-33-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Drop bdrv_format_default_perms()Max Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-32-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Make bdrv_filter_default_perms() staticMax Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-31-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Use child_of_bds in remaining placesMax Reitz
Replace child_file by child_of_bds in all remaining places (excluding tests). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-28-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Drop child_backingMax Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-25-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Make backing files child_of_bds childrenMax Reitz
Make all parents of backing files pass the appropriate BdrvChildRole. By doing so, we can switch their BdrvChildClass over to the generic child_of_bds, which will do the right thing when given a correct BdrvChildRole. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-24-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Drop child_formatMax Reitz
Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-23-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Add bdrv_default_perms()Max Reitz
This callback can be used by BDSs that use child_of_bds with the appropriate BdrvChildRole for their children. Also, make bdrv_format_default_perms() use it for child_of_bds children (just a temporary solution until we can drop bdrv_format_default_perms() altogether). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-20-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Relax *perms_for_storage for data childrenMax Reitz
We can be less restrictive about pure data children than those with metadata on them, so let bdrv_default_perms_for_storage() handle metadata children differently from pure data children. As explained in the code, the restrictions on metadata children are strictly stricter than those for pure data children, so in theory we just have to distinguish between pure-data and all other storage children (pure metadata or data+metadata). In practice, that is not obvious, though, so we have two independent code paths for metadata and for data children, and data+metadata children will go through both (without the path for data children doing anything meaningful). Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-19-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Pull out bdrv_default_perms_for_storage()Max Reitz
Right now, bdrv_format_default_perms() is used by format parents (generally). We want to switch to a model where most parents use a single BdrvChildClass, which then decides the permissions based on the child role. To do so, we have to split bdrv_format_default_perms() into separate functions for each such role. Note that bdrv_default_perms_for_storage() currently handles all DATA | METADATA children. A follow-up patch is going to split it further into one function for each case. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-18-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Pull out bdrv_default_perms_for_cow()Max Reitz
Right now, bdrv_format_default_perms() is used by format parents (generally). We want to switch to a model where most parents use a single BdrvChildClass, which then decides the permissions based on the child role. To do so, we have to split bdrv_format_default_perms() into separate functions for each such role. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-17-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Distinguish paths in *_format_default_permsMax Reitz
bdrv_format_default_perms() has one code path for backing files, and one for storage files. We want to pull them out into their own functions, so make sure they are completely distinct before so the next patches will be a bit cleaner. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20200513110544.176672-16-mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Add child_of_bdsMax Reitz
Any current user of child_file, child_format, and child_backing can and should use this generic BdrvChildClass instead, as it can handle all of these cases. However, to be able to do so, the users must pass the appropriate BdrvChildRole when the child is created/attached. (The following commits will take care of that.) Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-15-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Unify bdrv_child_cb_detach()Max Reitz
Make bdrv_child_cb_detach() call bdrv_backing_detach() for children with a COW role (and drop the reverse call from bdrv_backing_detach()), so it can be used for any child (with a proper role set). Because so far no child has a proper role set, we need a temporary new callback for child_backing.detach that ensures bdrv_backing_detach() is called for all COW children that do not have their role set yet. (Also, move bdrv_child_cb_detach() down to group it with bdrv_inherited_options() and bdrv_child_cb_attach().) Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-14-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Unify bdrv_child_cb_attach()Max Reitz
Make bdrv_child_cb_attach() call bdrv_backing_attach() for children with a COW role (and drop the reverse call from bdrv_backing_attach()), so it can be used for any child (with a proper role set). Because so far no child has a proper role set, we need a temporary new callback for child_backing.attach that ensures bdrv_backing_attach() is called for all COW children that do not have their role set yet. (Also, move bdrv_child_cb_attach() down to group it with bdrv_inherited_options().) Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-13-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Use bdrv_inherited_options()Max Reitz
Let child_file's, child_format's, and child_backing's .inherit_options() implementations fall back to bdrv_inherited_options() to show that it would really work for all of these cases, if only the parents passed the appropriate BdrvChildRole and parent_is_format values. (Also, make bdrv_open_inherit(), the only place to explicitly call bdrv_backing_options(), call bdrv_inherited_options() instead.) This patch should incur only two visible changes, both for child_format children, both of which are effectively bug fixes: First, they no longer have discard=unmap set by default. This reason it was set is because bdrv_inherited_fmt_options() fell through to bdrv_protocol_options(), and that set it because "format drivers take care to send flushes and respect unmap policy". None of the drivers that use child_format for their children (quorum and blkverify) are format drivers, though, so this reasoning does not apply here. Second, they no longer have BDRV_O_NO_IO force-cleared. child_format was used solely for children that do not store any metadata and as such will not be accessed by their parents as long as those parents do not receive I/O themselves. Thus, such children should inherit BDRV_O_NO_IO. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-12-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-05-18block: Add generic bdrv_inherited_options()Max Reitz
After the series this patch belongs to, we want to have a common BdrvChildClass that encompasses all of child_file, child_format, and child_backing. Such a single class needs a single .inherit_options() implementation, and this patch introduces it. The next patch will show how the existing implementations can fall back to it just by passing appropriate BdrvChildRole and parent_is_format values. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200513110544.176672-11-mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>