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>
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>
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>
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>
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>
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>
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>
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>
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>
