| Message ID | 20210224104707.88430-3-vsementsov@virtuozzo.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/6] qcow2-bitmap: make bytes_covered_by_bitmap_cluster() public | expand |
On 2/24/21 1:47 PM, Vladimir Sementsov-Ogievskiy wrote: > Actually L1 table entry offset is in 512 bytes sectors. Fix the spec. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > docs/interop/parallels.txt | 27 +++++++++++++++------------ > 1 file changed, 15 insertions(+), 12 deletions(-) > > diff --git a/docs/interop/parallels.txt b/docs/interop/parallels.txt > index f15bf35bd1..73af9a2c4b 100644 > --- a/docs/interop/parallels.txt > +++ b/docs/interop/parallels.txt > @@ -208,21 +208,24 @@ 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. > +Dirty bitmap is stored in the array of clusters inside Parallels Image file. > +Offsets of these clusters are saved in L1 offset table here. Each L1 table > +entry is a 64bit integer 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 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 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 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) Reviewed-by: Denis V. Lunev <den@openvz.org>
Am 24.02.2021 um 11:47 hat Vladimir Sementsov-Ogievskiy geschrieben: > Actually L1 table entry offset is in 512 bytes sectors. Fix the spec. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > docs/interop/parallels.txt | 27 +++++++++++++++------------ > 1 file changed, 15 insertions(+), 12 deletions(-) > > diff --git a/docs/interop/parallels.txt b/docs/interop/parallels.txt > index f15bf35bd1..73af9a2c4b 100644 > --- a/docs/interop/parallels.txt > +++ b/docs/interop/parallels.txt > @@ -208,21 +208,24 @@ 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. > +Dirty bitmap is stored in the array of clusters inside Parallels Image file. > +Offsets of these clusters are saved in L1 offset table here. Each L1 table > +entry is a 64bit integer described below: I think the English grammar needs some fixes here (missing articles). If I understand correctly, it's also not really an array, which I would understand as consecutive clusters. Maybe something like this: 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 L1 table entry is 0, all bits in the corresponding cluster of the bitmap > +are assumed to be 0. "an L1 table", like before. > -If an L1 table entry is 1, the corresponding cluster of the bitmap is assumed > -to have all bits set. > +If L1 table entry is 1, all bits in the corresponding cluster of the bitmap > +are assumed to be 1. Same here. > -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 corresponding cluster offset "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) These changes can be made while applying the patch. Kevin
diff --git a/docs/interop/parallels.txt b/docs/interop/parallels.txt index f15bf35bd1..73af9a2c4b 100644 --- a/docs/interop/parallels.txt +++ b/docs/interop/parallels.txt @@ -208,21 +208,24 @@ 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. +Dirty bitmap is stored in the array of clusters inside Parallels Image file. +Offsets of these clusters are saved in L1 offset table here. Each L1 table +entry is a 64bit integer 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 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 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 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)
Actually L1 table entry offset is in 512 bytes sectors. Fix the spec. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- docs/interop/parallels.txt | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-)