diff mbox

[2/3] mds: fix cap revoke race

Message ID 1372056089-11603-2-git-send-email-zheng.z.yan@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Yan, Zheng June 24, 2013, 6:41 a.m. UTC 
From: "Yan, Zheng" <zheng.z.yan@intel.com>

If caps are been revoking by the auth MDS, don't consider them as
issued even they are still issued by non-auth MDS. The non-auth
MDS should also be revoking/exporting these caps, the client just
hasn't received the cap revoke/export message.

The race I encountered is: When caps are exporting to new MDS, the
client receives cap import message and cap revoke message from the
new MDS, then receives cap export message from the old MDS. When
the client receives cap revoke message from the new MDS, the revoking
caps are still issued by the old MDS, so the client does nothing.
Later when the cap export message is received, the client removes
the caps issued by the old MDS. (Another way to fix the race is
calling ceph_check_caps() in handle_cap_export())

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
---
 fs/ceph/caps.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Yan, Zheng June 24, 2013, 8:19 a.m. UTC | #1 
This patch's title is wrong, please ignore it.

Thanks
Yan, Zheng

On 06/24/2013 02:41 PM, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@intel.com>
> 
> If caps are been revoking by the auth MDS, don't consider them as
> issued even they are still issued by non-auth MDS. The non-auth
> MDS should also be revoking/exporting these caps, the client just
> hasn't received the cap revoke/export message.
> 
> The race I encountered is: When caps are exporting to new MDS, the
> client receives cap import message and cap revoke message from the
> new MDS, then receives cap export message from the old MDS. When
> the client receives cap revoke message from the new MDS, the revoking
> caps are still issued by the old MDS, so the client does nothing.
> Later when the cap export message is received, the client removes
> the caps issued by the old MDS. (Another way to fix the race is
> calling ceph_check_caps() in handle_cap_export())
> 
> Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
> ---
>  fs/ceph/caps.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 9a5ccc9..a8c616b 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -697,6 +697,15 @@ int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented)
>  		if (implemented)
>  			*implemented |= cap->implemented;
>  	}
> +	/*
> +	 * exclude caps issued by non-auth MDS, but are been revoking
> +	 * by the auth MDS. The non-auth MDS should be revoking/exporting
> +	 * these caps, but the message is delayed.
> +	 */
> +	if (ci->i_auth_cap) {
> +		cap = ci->i_auth_cap;
> +		have &= ~cap->implemented | cap->issued;
> +	}
>  	return have;
>  }
>  
> 

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diff mbox

Patch

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 9a5ccc9..a8c616b 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -697,6 +697,15 @@  int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented)
 		if (implemented)
 			*implemented |= cap->implemented;
 	}
+	/*
+	 * exclude caps issued by non-auth MDS, but are been revoking
+	 * by the auth MDS. The non-auth MDS should be revoking/exporting
+	 * these caps, but the message is delayed.
+	 */
+	if (ci->i_auth_cap) {
+		cap = ci->i_auth_cap;
+		have &= ~cap->implemented | cap->issued;
+	}
 	return have;
 }