[PATCH v2] md/bitmap: don't read page from device with Bitmap_sync

[PATCH v2] md/bitmap: don't read page from device with Bitmap_sync

[Guoqing Jiang]

The device owns Bitmap_sync flag needs recovery
to become in sync, and read page from this type
device could get stale status.

Also add comments for Bitmap_sync bit per the
suggestion from Shaohua and Neil.

Previous disscussion can be found here:
https://marc.info/?t=149760428900004&r=1&w=2

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
---
 drivers/md/bitmap.c | 3 ++-
 drivers/md/md.h     | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index f4eace5..40f3cd7 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -156,7 +156,8 @@ static int read_sb_page(struct mddev *mddev, loff_t offset,
 
 	rdev_for_each(rdev, mddev) {
 		if (! test_bit(In_sync, &rdev->flags)
-		    || test_bit(Faulty, &rdev->flags))
+		    || test_bit(Faulty, &rdev->flags)
+		    || test_bit(Bitmap_sync, &rdev->flags))
 			continue;
 
 		target = offset + index * (PAGE_SIZE/512);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 991f0fe..b50eb4a 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -134,7 +134,9 @@ enum flag_bits {
 	Faulty,			/* device is known to have a fault */
 	In_sync,		/* device is in_sync with rest of array */
 	Bitmap_sync,		/* ..actually, not quite In_sync.  Need a
-				 * bitmap-based recovery to get fully in sync
+				 * bitmap-based recovery to get fully in sync.
+				 * The bit is only meaningful before device
+				 * has been passed to pers->hot_add_disk.
 				 */
 	WriteMostly,		/* Avoid reading if at all possible */
 	AutoDetected,		/* added by auto-detect */
-- 
2.10.0

Re: [PATCH v2] md/bitmap: don't read page from device with Bitmap_sync

[Shaohua Li]

On Tue, Jul 04, 2017 at 11:20:30AM +0800, Guoqing Jiang wrote:
> The device owns Bitmap_sync flag needs recovery
> to become in sync, and read page from this type
> device could get stale status.
> 
> Also add comments for Bitmap_sync bit per the
> suggestion from Shaohua and Neil.
> 
> Previous disscussion can be found here:
> https://marc.info/?t=149760428900004&r=1&w=2
> 
> Signed-off-by: Guoqing Jiang <gqjiang@suse.com>

Applied!
> ---
>  drivers/md/bitmap.c | 3 ++-
>  drivers/md/md.h     | 4 +++-
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
> index f4eace5..40f3cd7 100644
> --- a/drivers/md/bitmap.c
> +++ b/drivers/md/bitmap.c
> @@ -156,7 +156,8 @@ static int read_sb_page(struct mddev *mddev, loff_t offset,
>  
>  	rdev_for_each(rdev, mddev) {
>  		if (! test_bit(In_sync, &rdev->flags)
> -		    || test_bit(Faulty, &rdev->flags))
> +		    || test_bit(Faulty, &rdev->flags)
> +		    || test_bit(Bitmap_sync, &rdev->flags))
>  			continue;
>  
>  		target = offset + index * (PAGE_SIZE/512);
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 991f0fe..b50eb4a 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -134,7 +134,9 @@ enum flag_bits {
>  	Faulty,			/* device is known to have a fault */
>  	In_sync,		/* device is in_sync with rest of array */
>  	Bitmap_sync,		/* ..actually, not quite In_sync.  Need a
> -				 * bitmap-based recovery to get fully in sync
> +				 * bitmap-based recovery to get fully in sync.
> +				 * The bit is only meaningful before device
> +				 * has been passed to pers->hot_add_disk.
>  				 */
>  	WriteMostly,		/* Avoid reading if at all possible */
>  	AutoDetected,		/* added by auto-detect */
> -- 
> 2.10.0
>