[PATCH] rbd: add new snapshots at the tail

[PATCH] rbd: add new snapshots at the tail

[Alex Elder]

This fixes a bug that went in with this commit:

    commit f6e0c99092cca7be00fca4080cfc7081739ca544
    Author: Alex Elder <elder@inktank.com>
    Date:   Thu Aug 2 11:29:46 2012 -0500
    rbd: simplify __rbd_init_snaps_header()

The problem is that a new rbd snapshot needs to go either after an
existing snapshot entry, or at the *end* of an rbd device's snapshot
list.  As originally coded, it is placed at the beginning.  This was
based on the assumption the list would be empty (so it wouldn't
matter), but in fact if multiple new snapshots are added to an empty
list in one shot the list will be non-empty after the first one is
added.

This addresses http://tracker.newdream.net/issues/3063

Signed-off-by: Alex Elder <elder@inktank.com>
---
 drivers/block/rbd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 8e6e29e..fd51f9d 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2187,7 +2187,7 @@ static int __rbd_init_snaps_header(struct
rbd_device *rbd_dev)
 			if (snap)
 				list_add_tail(&new_snap->node, &snap->node);
 			else
-				list_add(&new_snap->node, head);
+				list_add_tail(&new_snap->node, head);
 		} else {
 			/* Already have this one */

-- 
1.7.9.5

Re: [PATCH] rbd: add new snapshots at the tail

[Josh Durgin]

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

On 09/04/2012 11:08 AM, Alex Elder wrote:
> This fixes a bug that went in with this commit:
>
>      commit f6e0c99092cca7be00fca4080cfc7081739ca544
>      Author: Alex Elder <elder@inktank.com>
>      Date:   Thu Aug 2 11:29:46 2012 -0500
>      rbd: simplify __rbd_init_snaps_header()
>
> The problem is that a new rbd snapshot needs to go either after an
> existing snapshot entry, or at the *end* of an rbd device's snapshot
> list.  As originally coded, it is placed at the beginning.  This was
> based on the assumption the list would be empty (so it wouldn't
> matter), but in fact if multiple new snapshots are added to an empty
> list in one shot the list will be non-empty after the first one is
> added.
>
> This addresses http://tracker.newdream.net/issues/3063
>
> Signed-off-by: Alex Elder <elder@inktank.com>
> ---
>   drivers/block/rbd.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 8e6e29e..fd51f9d 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -2187,7 +2187,7 @@ static int __rbd_init_snaps_header(struct
> rbd_device *rbd_dev)
>   			if (snap)
>   				list_add_tail(&new_snap->node, &snap->node);
>   			else
> -				list_add(&new_snap->node, head);
> +				list_add_tail(&new_snap->node, head);
>   		} else {
>   			/* Already have this one */
>