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| author | Vladimir Sementsov-Ogievskiy | 2021-02-24 11:47:03 +0100 |
|---|---|---|
| committer | Kevin Wolf | 2021-03-08 14:56:54 +0100 |
| commit | 67ae4ace9bce25d37be8dd97630ed336c29d6b72 (patch) | |
| tree | b173ba2384d0108521616bec5f9a27eba3e70ace /docs | |
| parent | qcow2-bitmap: make bytes_covered_by_bitmap_cluster() public (diff) | |
| download | qemu-67ae4ace9bce25d37be8dd97630ed336c29d6b72.tar.gz qemu-67ae4ace9bce25d37be8dd97630ed336c29d6b72.tar.xz qemu-67ae4ace9bce25d37be8dd97630ed336c29d6b72.zip | |
parallels.txt: fix bitmap L1 table description
Actually L1 table entry offset is in 512 bytes sectors. Fix the spec.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210224104707.88430-3-vsementsov@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/interop/parallels.txt | 28 |
1 files changed, 16 insertions, 12 deletions
diff --git a/docs/interop/parallels.txt b/docs/interop/parallels.txt index f15bf35bd1..bb3fadf369 100644 --- a/docs/interop/parallels.txt +++ b/docs/interop/parallels.txt @@ -208,21 +208,25 @@ of its data area are: 28 - 31: l1_size The number of entries in the L1 table of the bitmap. - variable: l1_table (8 * l1_size bytes) - L1 offset table (in bytes) + variable: L1 offset table (l1_table), size: 8 * l1_size bytes -A dirty bitmap is stored using a one-level structure for the mapping to host -clusters - an L1 table. +The dirty bitmap described by this feature extension is stored in a set of +clusters inside the Parallels image file. The offsets of these clusters are +saved in the L1 offset table specified by the feature extension. Each L1 table +entry is a 64 bit integer as described below: -Given an offset in bytes into the bitmap data, the offset in bytes into the -image file can be obtained as follows: +Given an offset in bytes into the bitmap data, corresponding L1 entry is - offset = l1_table[offset / cluster_size] + (offset % cluster_size) + l1_table[offset / cluster_size] -If an L1 table entry is 0, the corresponding cluster of the bitmap is assumed -to be zero. +If an L1 table entry is 0, all bits in the corresponding cluster of the bitmap +are assumed to be 0. -If an L1 table entry is 1, the corresponding cluster of the bitmap is assumed -to have all bits set. +If an L1 table entry is 1, all bits in the corresponding cluster of the bitmap +are assumed to be 1. -If an L1 table entry is not 0 or 1, it allocates a cluster from the data area. +If an L1 table entry is not 0 or 1, it contains the corresponding cluster +offset (in 512b sectors). Given an offset in bytes into the bitmap data the +offset in bytes into the image file can be obtained as follows: + + offset = l1_table[offset / cluster_size] * 512 + (offset % cluster_size) |