At Mon, 2 Mar 2015 16:02:37 +0800,
Liu Yuan wrote:
>
> From: Liu Yuan <liuy...@cmss.chinamobile.com>
>
> One of the acceleration for recovery is we try to recover the object from
> local
> node as much as possible. It is straightforward implemented:
>
> 1 firstly get the hash of the object to be recoveried from stale directry if
> any
> 2 then compare the fingerprint to the remote node
> 3 if identical, then we can safely recover it from local stale directory.
>
> But this logic is never executed in the following case:
>
> 0 sheep try to recover object A at from epoch 5, we note it as A.5
> 1 but sheep find we have a local copy A.2 due to a multiple node events
> 2 then sheep get the fingerprint of A.2 and then compare to remote node.
> 3 the figerprints are identical, so this sheep tries to recover it from A.2
> 4 if, unfortunately, A.5 is as well calcuated onto this node, even though this
> sheep dosen't have it, our code will first try to link A.5
> 5 unfortunately, A.5 is never out there and before we really try to link A.2,
> sheep fail out because ->link(A.5) return error.
>
> The fix is easy, just try to ->link(A.2) before ->link(A.5).
>
> Signed-off-by: Liu Yuan <liuy...@cmss.chinamobile.com>
> ---
> sheep/recovery.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
Applied this series, thanks.
Hitoshi
>
> diff --git a/sheep/recovery.c b/sheep/recovery.c
> index 8d94d4f..36ef8a0 100644
> --- a/sheep/recovery.c
> +++ b/sheep/recovery.c
> @@ -265,13 +265,6 @@ static int recover_object_from(struct recovery_obj_work
> *row,
> struct sd_rsp *rsp = (struct sd_rsp *)&hdr;
> struct siocb iocb = { 0 };
>
> - if (node_is_local(node)) {
> - if (tgt_epoch < sys_epoch())
> - return sd_store->link(oid, tgt_epoch);
> -
> - return SD_RES_NO_OBJ;
> - }
> -
> /* compare sha1 hash value first */
> if (local_epoch > 0) {
> sd_init_req(&hdr, SD_OP_GET_HASH);
> @@ -290,6 +283,13 @@ static int recover_object_from(struct recovery_obj_work
> *row,
> }
> }
>
> + if (node_is_local(node)) {
> + if (tgt_epoch < sys_epoch())
> + return sd_store->link(oid, tgt_epoch);
> +
> + return SD_RES_NO_OBJ;
> + }
> +
> rlen = get_store_objsize(oid);
> buf = xvalloc(rlen);
>
> --
> 1.9.1
>
> --
> sheepdog mailing list
> sheepdog@lists.wpkg.org
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