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author | Peter Maydell <peter.maydell@linaro.org> | 2020-12-31 23:26:46 +0000 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2020-12-31 23:26:46 +0000 |
commit | 26f6b15e2636eb20cb6757093170341b22fe6fbc (patch) | |
tree | 147896371dd546414557fdbed8f35b622ee4aae2 /docs | |
parent | c7e48f91653d6ace9dc42ec6b5b627b57d5d49e0 (diff) | |
parent | 0e72078128229bf9efb542e396ab44bf91b91340 (diff) | |
download | qemu-26f6b15e2636eb20cb6757093170341b22fe6fbc.zip qemu-26f6b15e2636eb20cb6757093170341b22fe6fbc.tar.gz qemu-26f6b15e2636eb20cb6757093170341b22fe6fbc.tar.bz2 |
Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2020-12-18' into staging
Block patches:
- New block filter: preallocate (which, on writes beyond an image file's
end, allocates big chunks of data so that such post-EOF writes will
occur less frequently)
- write-zeroes and block-status support for Quorum
- Implementation of truncate for the nvme block driver similarly to the
existing implementations for host block devices and iscsi devices
- Block layer refactoring: Drop the tighten_restrictions concept in the
block permission functions
- iotest fixes
# gpg: Signature made Fri 18 Dec 2020 14:45:30 GMT
# gpg: using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40
# gpg: issuer "mreitz@redhat.com"
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full]
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1 1829 F407 DB00 61D5 CF40
* remotes/maxreitz/tags/pull-block-2020-12-18: (30 commits)
iotests: Fix _send_qemu_cmd with bash 5.1
iotests/102: Pass $QEMU_HANDLE to _send_qemu_cmd
block/nvme: Implement fake truncate() coroutine
quorum: Implement bdrv_co_pwrite_zeroes()
quorum: Implement bdrv_co_block_status()
scripts/simplebench: add bench_prealloc.py
simplebench/results_to_text: make executable
simplebench/results_to_text: add difference line to the table
simplebench/results_to_text: improve view of the table
simplebench: move results_to_text() into separate file
simplebench: rename ascii() to results_to_text()
scripts/simplebench: use standard deviation for +- error
scripts/simplebench: support iops
scripts/simplebench: fix grammar: s/successed/succeeded/
iotests: add 298 to test new preallocate filter driver
iotests.py: execute_setup_common(): add required_fmts argument
iotests: qemu_io_silent: support --image-opts
qemu-io: add preallocate mode parameter for truncate command
block: introduce preallocate filter
block: bdrv_check_perm(): process children anyway
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs')
-rw-r--r-- | docs/system/qemu-block-drivers.rst.inc | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc index b052a6d..60a064b 100644 --- a/docs/system/qemu-block-drivers.rst.inc +++ b/docs/system/qemu-block-drivers.rst.inc @@ -952,3 +952,29 @@ on host and see if there are locks held by the QEMU process on the image file. More than one byte could be locked by the QEMU instance, each byte of which reflects a particular permission that is acquired or protected by the running block driver. + +Filter drivers +~~~~~~~~~~~~~~ + +QEMU supports several filter drivers, which don't store any data, but perform +some additional tasks, hooking io requests. + +.. program:: filter-drivers +.. option:: preallocate + + The preallocate filter driver is intended to be inserted between format + and protocol nodes and preallocates some additional space + (expanding the protocol file) when writing past the file’s end. This can be + useful for file-systems with slow allocation. + + Supported options: + + .. program:: preallocate + .. option:: prealloc-align + + On preallocation, align the file length to this value (in bytes), default 1M. + + .. program:: preallocate + .. option:: prealloc-size + + How much to preallocate (in bytes), default 128M. |