file-posix: Fix alignment after reopen changing O_DIRECT

At the end of a reopen, we already call bdrv_refresh_limits(), which
should update bs->request_alignment according to the new file
descriptor

file-posix: Fix alignment after reopen changing O_DIRECT

At the end of a reopen, we already call bdrv_refresh_limits(), which
should update bs->request_alignment according to the new file
descriptor. However, raw_probe_alignment() relies on s->needs_alignment
and just uses 1 if it isn't set. We neglected to update this field, so
starting with cache=writeback and then reopening with cache=none means
that we get an incorrect bs->request_alignment == 1 and unaligned
requests fail instead of being automatically aligned.

Fix this by recalculating s->needs_alignment in raw_refresh_limits()
before calling raw_probe_alignment().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20211104113109.56336-1-kwolf@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20211115145409.176785-13-kwolf@redhat.com>
[hreitz: Fix iotest 142 for block sizes greater than 512 by operating on
a file with a size of 1 MB]
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20211116101431.105252-1-hreitz@redhat.com>

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iotests: Specify explicit backing format where sensible

There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become

iotests: Specify explicit backing format where sensible

There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.

The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.

iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

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iotests: Use _rm_test_img for deleting test images

Just rm will not delete external data files. Use _rm_test_img every
time we delete a test image.

(In the process, clean up the indentation of eve

iotests: Use _rm_test_img for deleting test images

Just rm will not delete external data files. Use _rm_test_img every
time we delete a test image.

(In the process, clean up the indentation of every _cleanup() this patch
touches.)

((Also, use quotes consistently. I am happy to see unquoted instances
like "rm -rf $TEST_DIR/..." go.))

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-id: 20191107163708.833192-16-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

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tests/qemu-iotests: Remove the "_supported_os Linux" line from many tests

A lot of tests run fine on FreeBSD and macOS, too - the limitation
to Linux here was likely just copied-and-pasted from othe

tests/qemu-iotests: Remove the "_supported_os Linux" line from many tests

A lot of tests run fine on FreeBSD and macOS, too - the limitation
to Linux here was likely just copied-and-pasted from other tests.
Thus remove the "_supported_os Linux" line from tests that run
successful in our CI pipelines on FreeBSD and macOS.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20190502084506.8009-6-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

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qemu-iotests: Improve portability by searching bash in the $PATH

Bash is not always installed as /bin/bash. In particular on OpenBSD,
the package installs it in /usr/local/bin.
Use the 'env' shebang

qemu-iotests: Improve portability by searching bash in the $PATH

Bash is not always installed as /bin/bash. In particular on OpenBSD,
the package installs it in /usr/local/bin.
Use the 'env' shebang to search bash in the $PATH.

Patch created mechanically by running:

$ git grep -lE '#! ?/bin/bash' -- tests/qemu-iotests \
| while read f; do \
sed -i 's|^#!.\?/bin/bash$|#!/usr/bin/env bash|' $f; \
done

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

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iotests: Drop use of bash keyword 'function'

Bash allows functions to be declared with or without the leading
keyword 'function'; but including the keyword does not comply with
POSIX syntax, and is

iotests: Drop use of bash keyword 'function'

Bash allows functions to be declared with or without the leading
keyword 'function'; but including the keyword does not comply with
POSIX syntax, and is confusing to ksh users where the use of the
keyword changes the scoping rules for functions. Stick to the
POSIX form through iotests.

Done mechanically with:
sed -i 's/^function //' $(git ls-files tests/qemu-iotests)

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20181116215002.2124581-1-eblake@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

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qemu-iotests: remove unused variable 'here'

Running
git grep '\$here' tests/qemu-iotests

has 0 hits, which means we are setting a variable that has
no use. It appears that commit e8f8624d removed

qemu-iotests: remove unused variable 'here'

Running
git grep '\$here' tests/qemu-iotests

has 0 hits, which means we are setting a variable that has
no use. It appears that commit e8f8624d removed the last
use. So execute the following cmd to remove all of
the 'here=...' lines as dead code.

sed -i '/^here=/d' $(git grep -l '^here=' tests/qemu-iotests)

Cc: kwolf@redhat.com
Cc: mreitz@redhat.com
Cc: eblake@redhat.com
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Mao Zhongyi <maozhongyi@cmss.chinamobile.com>
Message-Id: <20181024094051.4470-3-maozhongyi@cmss.chinamobile.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: touch up commit message, reorder series, rebase to master]
Signed-off-by: Eric Blake <eblake@redhat.com>

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tests: Avoid non-portable 'echo -ARG'

POSIX says that backslashes in the arguments to 'echo', as well as
any use of 'echo -n' and 'echo -e', are non-portable; it recommends
people should favor 'prin

tests: Avoid non-portable 'echo -ARG'

POSIX says that backslashes in the arguments to 'echo', as well as
any use of 'echo -n' and 'echo -e', are non-portable; it recommends
people should favor 'printf' instead. This is definitely true where
we do not control which shell is running (such as in makefile snippets
or in documentation examples). But even for scripts where we
require bash (and therefore, where echo does what we want by default),
it is still possible to use 'shopt -s xpg_echo' to change bash's
behavior of echo. And setting a good example never hurts when we are
not sure if a snippet will be copied from a bash-only script to a
general shell script (although I don't change the use of non-portable
\e for ESC when we know the running shell is bash).

Replace 'echo -n "..."' with 'printf %s "..."', and 'echo -e "..."'
with 'printf %b "...\n"', with the optimization that the %s/%b
argument can be omitted if the string being printed is a strict
literal with no '%', '$', or '`' (we could technically also make
this optimization when there are $ or `` substitutions but where
we can prove their results will not be problematic, but proving
that such substitutions are safe makes the patch less trivial
compared to just being consistent).

In the qemu-iotests check script, fix unusual shell quoting
that would result in word-splitting if 'date' outputs a space.

In test 051, take an opportunity to shorten the line.

In test 068, get rid of a pointless second invocation of bash.

CC: qemu-trivial@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-id: 20170703180950.9895-1-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

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qemu-iotests: Filter HMP readline escape characters

The only thing the escape characters achieve is making the reference
output unreadable and lines that are potentially so long that git
doesn't wan

qemu-iotests: Filter HMP readline escape characters

The only thing the escape characters achieve is making the reference
output unreadable and lines that are potentially so long that git
doesn't want to put them into an email any more. Let's filter them out.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

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qemu-iotests: tests: do not set unused tmp variable

The previous commit removed the last usage of ${tmp} inside the tests
themselves; the only remaining users are sourced by check. So we can now
dro

qemu-iotests: tests: do not set unused tmp variable

The previous commit removed the last usage of ${tmp} inside the tests
themselves; the only remaining users are sourced by check. So we can now
drop this variable from the tests.

Signed-off-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Reviewed-by: Bo Tu <tubo@linux.vnet.ibm.com>
Message-id: 1460472980-26319-4-git-send-email-silbe@linux.vnet.ibm.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

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block: Remove BDRV_O_CACHE_WB

The previous patches have successively made blk->enable_write_cache the
true source for the information whether a writethrough mode must be
implemented. The correspondi

block: Remove BDRV_O_CACHE_WB

The previous patches have successively made blk->enable_write_cache the
true source for the information whether a writethrough mode must be
implemented. The corresponding BDRV_O_CACHE_WB is only useless baggage
we're carrying around, so now's the time to remove it.

At the same time, we remove the 'cache.writeback' option parsing on the
BDS level as the only effect was setting the BDRV_O_CACHE_WB flag.

This change requires test cases that explicitly enabled the option to
drop it. Other than that and the change of the error message when
writethrough is enabled on the BDS level (from "Can't set writethrough
mode" to "doesn't support the option"), there should be no change in
behaviour.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

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qemu-io: Use bdrv_parse_cache_mode() in reopen_f()

We must forbid changing the WCE flag in bdrv_reopen() in the same patch,
as otherwise the behaviour would change so that the flag takes
precedence

qemu-io: Use bdrv_parse_cache_mode() in reopen_f()

We must forbid changing the WCE flag in bdrv_reopen() in the same patch,
as otherwise the behaviour would change so that the flag takes
precedence over the explicitly specified option.

The correct value of the WCE flag depends on the BlockBackend user (e.g.
guest device) and isn't a decision that the QMP client makes, so this
change is what we want.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

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block/qapi: Use blk_enable_write_cache()

Now that WCE is handled on the BlockBackend level, the flag is
meaningless for BDSes. As the schema requires us to fill the field,
we return an enabled write

block/qapi: Use blk_enable_write_cache()

Now that WCE is handled on the BlockBackend level, the flag is
meaningless for BDSes. As the schema requires us to fill the field,
we return an enabled write cache for them.

Note that this means that querying the BlockBackend name may return
writethrough as the cache information, whereas querying the node-name of
the root of that same BlockBackend will return writeback.

This may appear odd at first, but it actually makes sense because it
correctly repesents the layer that implements the WCE handling. This
becomes more apparent when you consider nodes that are the root node of
multiple BlockBackends, where each BB can have its own WCE setting.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

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block: Move enable_write_cache to BB level

Whether a write cache is used or not is a decision that concerns the
user (e.g. the guest device) rather than the backend. It was already
logically part of

block: Move enable_write_cache to BB level

Whether a write cache is used or not is a decision that concerns the
user (e.g. the guest device) rather than the backend. It was already
logically part of the BB level as bdrv_move_feature_fields() always kept
it on top of the BDS tree; with this patch, the core of it (the actual
flag and the additional flushes) is also implemented there.

Direct callers of bdrv_open() must pass BDRV_O_CACHE_WB now if bs
doesn't have a BlockBackend attached.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

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block: Reject writethrough mode except at the root

Writethrough mode is going to become a BlockBackend feature rather than
a BDS one, so forbid it in places where we won't be able to support it
when

block: Reject writethrough mode except at the root

Writethrough mode is going to become a BlockBackend feature rather than
a BDS one, so forbid it in places where we won't be able to support it
when the code finally matches the envisioned design.

We only allowed setting the cache mode of non-root nodes after the 2.5
release, so we're still free to make this change.

The target of block jobs is now always opened in a writeback mode
because it doesn't have a BlockBackend attached. This makes more sense
anyway because block jobs know when to flush. If the graph is modified
on job completion, the original cache mode moves to the new root, so
for the guest device writethough always stays enabled if it was
configured this way.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

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qemu-iotests: Test cache mode option inheritance

This is doing a more complete test on setting cache modes both while
opening an image (i.e. in a -drive command line) and in reopen
situations. It ch

qemu-iotests: Test cache mode option inheritance

This is doing a more complete test on setting cache modes both while
opening an image (i.e. in a -drive command line) and in reopen
situations. It checks that reopen can specify options for child nodes
and that cache modes are correctly inherited from parent nodes where
they are not specified.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>

show more ...