[PATCH 02/24] Add number of nodes to bitmap structure for clustering

[PATCH 02/24] Add number of nodes to bitmap structure for clustering

[Goldwyn Rodrigues]

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
---
 drivers/md/bitmap.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h
index 30210b9..6872945 100644
--- a/drivers/md/bitmap.h
+++ b/drivers/md/bitmap.h
@@ -128,10 +128,11 @@ typedef struct bitmap_super_s {
 	__le32 chunksize;    /* 52  the bitmap chunk size in bytes */
 	__le32 daemon_sleep; /* 56  seconds between disk flushes */
 	__le32 write_behind; /* 60  number of outstanding write-behind writes */
-	__le32 sectors_reserved; /* 64 number of 512-byte sectors that are
+	__le32 nodes;        /* 64 the maximum number of nodes in cluster. */
+	__le32 sectors_reserved; /* 68 number of 512-byte sectors that are
 				  * reserved for the bitmap. */
 
-	__u8  pad[256 - 68]; /* set to zero */
+	__u8  pad[256 - 72]; /* set to zero */
 } bitmap_super_t;
 
 /* notes:
-- 
2.1.2

Re: [PATCH 02/24] Add number of nodes to bitmap structure for clustering

[NeilBrown]

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On Thu, 18 Dec 2014 10:15:23 -0600 Goldwyn Rodrigues <rgoldwyn@suse.de> wrote:

> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
> ---
>  drivers/md/bitmap.h | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h
> index 30210b9..6872945 100644
> --- a/drivers/md/bitmap.h
> +++ b/drivers/md/bitmap.h
> @@ -128,10 +128,11 @@ typedef struct bitmap_super_s {
>  	__le32 chunksize;    /* 52  the bitmap chunk size in bytes */
>  	__le32 daemon_sleep; /* 56  seconds between disk flushes */
>  	__le32 write_behind; /* 60  number of outstanding write-behind writes */
> -	__le32 sectors_reserved; /* 64 number of 512-byte sectors that are
> +	__le32 nodes;        /* 64 the maximum number of nodes in cluster. */
> +	__le32 sectors_reserved; /* 68 number of 512-byte sectors that are
>  				  * reserved for the bitmap. */
>  
> -	__u8  pad[256 - 68]; /* set to zero */
> +	__u8  pad[256 - 72]; /* set to zero */
>  } bitmap_super_t;
>  
>  /* notes:

Hi Goldwyn,
 I was reviewing you latest series to make sure it wouldn't affect the
 non-clustered use case at all, and I found this.  I really should have
 noticed it earlier....

 You are changing the location of 'sectors_reserved' in the bitmap superblock.
 That obviously cannot be allowed - new fields must always be added to the
 end.

 Can you update the series in git to fix that please?  Then I will pull it in
 for -next.

Thanks,
NeilBrown

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Re: [PATCH 02/24] Add number of nodes to bitmap structure for clustering

[Goldwyn Rodrigues]

Hi Neil,

On 02/22/2015 07:38 PM, NeilBrown wrote:
> On Thu, 18 Dec 2014 10:15:23 -0600 Goldwyn Rodrigues <rgoldwyn@suse.de> wrote:
>
>> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
>> ---
>>   drivers/md/bitmap.h | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/md/bitmap.h b/drivers/md/bitmap.h
>> index 30210b9..6872945 100644
>> --- a/drivers/md/bitmap.h
>> +++ b/drivers/md/bitmap.h
>> @@ -128,10 +128,11 @@ typedef struct bitmap_super_s {
>>   	__le32 chunksize;    /* 52  the bitmap chunk size in bytes */
>>   	__le32 daemon_sleep; /* 56  seconds between disk flushes */
>>   	__le32 write_behind; /* 60  number of outstanding write-behind writes */
>> -	__le32 sectors_reserved; /* 64 number of 512-byte sectors that are
>> +	__le32 nodes;        /* 64 the maximum number of nodes in cluster. */
>> +	__le32 sectors_reserved; /* 68 number of 512-byte sectors that are
>>   				  * reserved for the bitmap. */
>>
>> -	__u8  pad[256 - 68]; /* set to zero */
>> +	__u8  pad[256 - 72]; /* set to zero */
>>   } bitmap_super_t;
>>
>>   /* notes:
>
> Hi Goldwyn,
>   I was reviewing you latest series to make sure it wouldn't affect the
>   non-clustered use case at all, and I found this.  I really should have
>   noticed it earlier....
>
>   You are changing the location of 'sectors_reserved' in the bitmap superblock.
>   That obviously cannot be allowed - new fields must always be added to the
>   end.

Oops. Sorry.

>
>   Can you update the series in git to fix that please?  Then I will pull it in
>   for -next.

I have done this and re-tested. However, I also rebased against 
upstream. There were some conflicts with respect to md_personality. I 
have re-done those patches, but it would be worth a second look. The one 
which may need special review attention is "bitmap_create returns bitmap 
pointer"


Regards,

-- 
Goldwyn