* [PATCH v2] design: fix computation of buffer log item bitmap size
@ 2022-01-04 1:58 Darrick J. Wong
2022-01-04 4:22 ` Chandan Babu R
0 siblings, 1 reply; 2+ messages in thread
From: Darrick J. Wong @ 2022-01-04 1:58 UTC (permalink / raw)
To: xfs, chandan.babu; +Cc: Wengang Wang
From: Darrick J. Wong <djwong@kernel.org>
Wengang Wang was trying to work through a buffer log item by consulting
the ondisk format documentation, and was confused by the formula given
in section 14.3.14 regarding the size of blf_data_map, aka the dirty
bitmap for buffer log items. We noticed that the documentation doesn't
match what the kernel actually does, so let's fix this.
Reported-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
.../journaling_log.asciidoc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/design/XFS_Filesystem_Structure/journaling_log.asciidoc b/design/XFS_Filesystem_Structure/journaling_log.asciidoc
index 8421a53..ddcb87f 100644
--- a/design/XFS_Filesystem_Structure/journaling_log.asciidoc
+++ b/design/XFS_Filesystem_Structure/journaling_log.asciidoc
@@ -867,7 +867,7 @@ The size of +blf_data_map+, in 32-bit words.
This variable-sized array acts as a dirty bitmap for the logged buffer. Each
1 bit represents a dirty region in the buffer, and each run of 1 bits
corresponds to a subsequent log item containing the new contents of the buffer
-area. Each bit represents +(blf_len * 512) / (blf_map_size * NBBY)+ bytes.
+area. Each bit represents +XFS_BLF_CHUNK+ (i.e. 128) bytes.
[[Buffer_Data_Log_Item]]
=== Buffer Data Log Item
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] design: fix computation of buffer log item bitmap size
2022-01-04 1:58 [PATCH v2] design: fix computation of buffer log item bitmap size Darrick J. Wong
@ 2022-01-04 4:22 ` Chandan Babu R
0 siblings, 0 replies; 2+ messages in thread
From: Chandan Babu R @ 2022-01-04 4:22 UTC (permalink / raw)
To: Darrick J. Wong; +Cc: xfs, Wengang Wang
On 04 Jan 2022 at 07:28, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Wengang Wang was trying to work through a buffer log item by consulting
> the ondisk format documentation, and was confused by the formula given
> in section 14.3.14 regarding the size of blf_data_map, aka the dirty
> bitmap for buffer log items. We noticed that the documentation doesn't
> match what the kernel actually does, so let's fix this.
>
> Reported-by: Wengang Wang <wen.gang.wang@oracle.com>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Looks good.
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
> ---
> .../journaling_log.asciidoc | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/design/XFS_Filesystem_Structure/journaling_log.asciidoc b/design/XFS_Filesystem_Structure/journaling_log.asciidoc
> index 8421a53..ddcb87f 100644
> --- a/design/XFS_Filesystem_Structure/journaling_log.asciidoc
> +++ b/design/XFS_Filesystem_Structure/journaling_log.asciidoc
> @@ -867,7 +867,7 @@ The size of +blf_data_map+, in 32-bit words.
> This variable-sized array acts as a dirty bitmap for the logged buffer. Each
> 1 bit represents a dirty region in the buffer, and each run of 1 bits
> corresponds to a subsequent log item containing the new contents of the buffer
> -area. Each bit represents +(blf_len * 512) / (blf_map_size * NBBY)+ bytes.
> +area. Each bit represents +XFS_BLF_CHUNK+ (i.e. 128) bytes.
>
> [[Buffer_Data_Log_Item]]
> === Buffer Data Log Item
--
chandan
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2022-01-04 4:22 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-01-04 1:58 [PATCH v2] design: fix computation of buffer log item bitmap size Darrick J. Wong
2022-01-04 4:22 ` Chandan Babu R
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox