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[Qemu-devel] [PATCH v4 1/3] block: add bdrv_get_format_alloc_stat format
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[Qemu-devel] [PATCH v4 1/3] block: add bdrv_get_format_alloc_stat format interface |
Date: |
Sat, 29 Jul 2017 19:41:02 +0300 |
The function should collect statistics, about used/unused by top-level
format driver space (in its .file) and allocation status
(data/zero/discarded/after-eof) of corresponding areas in this .file.
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
block.c | 16 +++++++++++
include/block/block.h | 3 ++
include/block/block_int.h | 2 ++
qapi/block-core.json | 72 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 93 insertions(+)
diff --git a/block.c b/block.c
index 50ba264143..7d720ae0c2 100644
--- a/block.c
+++ b/block.c
@@ -3407,6 +3407,22 @@ int64_t bdrv_get_allocated_file_size(BlockDriverState
*bs)
}
/**
+ * Collect format allocation info. See BlockFormatAllocInfo definition in
+ * qapi/block-core.json.
+ */
+int bdrv_get_format_alloc_stat(BlockDriverState *bs, BlockFormatAllocInfo
*bfai)
+{
+ BlockDriver *drv = bs->drv;
+ if (!drv) {
+ return -ENOMEDIUM;
+ }
+ if (drv->bdrv_get_format_alloc_stat) {
+ return drv->bdrv_get_format_alloc_stat(bs, bfai);
+ }
+ return -ENOTSUP;
+}
+
+/**
* Return number of sectors on success, -errno on error.
*/
int64_t bdrv_nb_sectors(BlockDriverState *bs)
diff --git a/include/block/block.h b/include/block/block.h
index 9b355e92d8..646376a772 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -335,6 +335,9 @@ typedef enum {
int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
+int bdrv_get_format_alloc_stat(BlockDriverState *bs,
+ BlockFormatAllocInfo *bfai);
+
/* The units of offset and total_work_size may be chosen arbitrarily by the
* block driver; total_work_size may change during the course of the amendment
* operation */
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8d3724cce6..458c715e99 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -208,6 +208,8 @@ struct BlockDriver {
int64_t (*bdrv_getlength)(BlockDriverState *bs);
bool has_variable_length;
int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
+ int (*bdrv_get_format_alloc_stat)(BlockDriverState *bs,
+ BlockFormatAllocInfo *bfai);
int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs,
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index ea0b3e8b13..93f6995381 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -139,6 +139,78 @@
'*format-specific': 'ImageInfoSpecific' } }
##
+# @BlockFormatAllocInfo:
+#
+#
+# Allocation information of an underlying protocol file, as partitioned by a
+# format driver's utilization of said allocations.
+# All fields are in bytes.
+#
+# Regions of the underlying protocol file may be considered used or unused by
+# the format driver interpreting these regions. It is at the discretion of the
+# format driver (e.g. qcow2) which regions of its backing storage are
considered
+# in-use or not.
+#
+# For now, the only format driver supporting this feature is Qcow2 which is a
+# cluster based format. Clusters considered in-use by qcow2 are those with a
+# non-zero refcount in the format metadata. All other clusters, if present, are
+# considered unused. Examples of unused allocations for the Qcow2 format are
+# leaked clusters, pre-allocated clusters, and recently freed clusters.
+#
+# Note: the whole underlying protocol file is described as well as all format
+# file allocations, not only virtual disk data (metadata, internal snapshots,
+# etc. are included).
+#
+# For the underlying protocol file there are native block-status types of the
+# regions:
+# - data: allocated data
+# - zero: reported as zero (for example, this type corresponds to holes for
+# POSIX files on sparce file-system)
+# - discarded: not allocated
+# 4th additional type is 'overrun', is data referenced by the format driver
+# located beyond EOF of the underlying protocol file. For example, a partially
+# allocated cluster at the end of a QCOW2 file, where Qcow2 generally operates
+# on complete clusters.
+#
+# So, the fields are:
+#
+# @used-data: used by the format file and backed by data in the underlying
+# protocol file
+#
+# @used-zero: used by the format file and backed by zeroes in the underlying
+# protocol file; which may be a filesystem hole for POSIX files.
+#
+# @used-discarded: used by the format file but actually unallocated in the
+# underlying protocol file
+#
+# @used-overrun: used by the format file beyond the end of the underlying
+# protocol file
+#
+# @unused-data: allocated data in the underlying protocol file not used by the
+# format file
+#
+# @unused-zero: reported-as-zero regions in the underlying protocol file not
+# used by the format file
+#
+# @unused-discarded: unallocated areas in the underlying protocol file not used
+# by the format file
+#
+# Note: sum of 6 fields {used,unused}-{data,zero,discarded} is equal to the
+# length of the underlying protocol file.
+#
+# Since: 2.11
+#
+##
+{ 'struct': 'BlockFormatAllocInfo',
+ 'data': {'used-data': 'uint64',
+ 'used-zero': 'uint64',
+ 'used-discarded': 'uint64',
+ 'used-overrun': 'uint64',
+ 'unused-data': 'uint64',
+ 'unused-zero': 'uint64',
+ 'unused-discarded': 'uint64' } }
+
+##
# @ImageCheck:
#
# Information about a QEMU image file check
--
2.11.1