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authorVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>2020-10-21 17:58:46 +0300
committerMax Reitz <mreitz@redhat.com>2020-12-18 12:35:55 +0100
commit33fa2222eb044147e75e5ec395e1fd53328bc9fb (patch)
treeab0ecf1c0054e6eefbbcad0d015c2b677e76f0ad /qapi
parent9530a25b8b7eb5cc1800b66ee617610cd43f0fad (diff)
downloadfocaccia-qemu-33fa2222eb044147e75e5ec395e1fd53328bc9fb.tar.gz
focaccia-qemu-33fa2222eb044147e75e5ec395e1fd53328bc9fb.zip
block: introduce preallocate filter
It's intended to be inserted between format and protocol nodes to
preallocate additional space (expanding protocol file) on writes
crossing EOF. It improves performance for file-systems with slow
allocation.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201021145859.11201-9-vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
[mreitz: Two comment fixes, and bumped the version from 5.2 to 6.0]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'qapi')
-rw-r--r--qapi/block-core.json20
1 files changed, 19 insertions, 1 deletions
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 04c5196e59..3484986d1c 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2829,7 +2829,7 @@
             'cloop', 'compress', 'copy-on-read', 'dmg', 'file', 'ftp', 'ftps',
             'gluster', 'host_cdrom', 'host_device', 'http', 'https', 'iscsi',
             'luks', 'nbd', 'nfs', 'null-aio', 'null-co', 'nvme', 'parallels',
-            'qcow', 'qcow2', 'qed', 'quorum', 'raw', 'rbd',
+            'preallocate', 'qcow', 'qcow2', 'qed', 'quorum', 'raw', 'rbd',
             { 'name': 'replication', 'if': 'defined(CONFIG_REPLICATION)' },
             'sheepdog',
             'ssh', 'throttle', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat' ] }
@@ -3099,6 +3099,23 @@
             'luks': 'QCryptoBlockOptionsLUKS'} }
 
 ##
+# @BlockdevOptionsPreallocate:
+#
+# Filter driver intended to be inserted between format and protocol node
+# and do preallocation in protocol node on write.
+#
+# @prealloc-align: on preallocation, align file length to this number,
+#                  default 1048576 (1M)
+#
+# @prealloc-size: how much to preallocate, default 134217728 (128M)
+#
+# Since: 6.0
+##
+{ 'struct': 'BlockdevOptionsPreallocate',
+  'base': 'BlockdevOptionsGenericFormat',
+  'data': { '*prealloc-align': 'int', '*prealloc-size': 'int' } }
+
+##
 # @BlockdevOptionsQcow2:
 #
 # Driver specific block device options for qcow2.
@@ -4006,6 +4023,7 @@
       'null-co':    'BlockdevOptionsNull',
       'nvme':       'BlockdevOptionsNVMe',
       'parallels':  'BlockdevOptionsGenericFormat',
+      'preallocate':'BlockdevOptionsPreallocate',
       'qcow2':      'BlockdevOptionsQcow2',
       'qcow':       'BlockdevOptionsQcow',
       'qed':        'BlockdevOptionsGenericCOWFormat',