[Ocfs2-devel] [PATCH 1/3] ocfs2: avoid inode removed while nfsd access it

[Junxiao Bi <junxiao.bi@oracle.com>]

On 6/14/20 5:26 AM, Joseph Qi wrote:

> Hi Junxiao,
>
> On 2020/6/12 08:19, Junxiao Bi wrote:
>> When nfsd is getting file dentry using handle or parent dentry of some
>> dentry, one cluster lock is used to avoid inode removed from other node,
>> but it still could be removed from local node, so use a rw lock to avoid
>> this.
>>
>> Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
>> ---
>>   fs/ocfs2/dlmglue.c | 17 ++++++++++++++---
>>   fs/ocfs2/ocfs2.h   |  1 +
>>   2 files changed, 15 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
>> index 152a0fc4e905..c5e84314e203 100644
>> --- a/fs/ocfs2/dlmglue.c
>> +++ b/fs/ocfs2/dlmglue.c
>> @@ -678,15 +678,17 @@ static void ocfs2_rename_lock_res_init(struct ocfs2_lock_res *res,
>>   				   &ocfs2_rename_lops, osb);
>>   }
>>   
>> -static void ocfs2_nfs_sync_lock_res_init(struct ocfs2_lock_res *res,
>> -					 struct ocfs2_super *osb)
>> +static void ocfs2_nfs_sync_lock_res_init(struct ocfs2_super *osb)
>>   {
>> +	struct ocfs2_lock_res *res = &osb->osb_nfs_sync_lockres;
>> +
>>   	/* nfs_sync lockres doesn't come from a slab so we call init
>>   	 * once on it manually.  */
>>   	ocfs2_lock_res_init_once(res);
>>   	ocfs2_build_lock_name(OCFS2_LOCK_TYPE_NFS_SYNC, 0, 0, res->l_name);
>>   	ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_NFS_SYNC,
>>   				   &ocfs2_nfs_sync_lops, osb);
>> +	init_rwsem(&osb->nfs_sync_rwlock);
>>   }
> Can we leave this and introduce a new one to initialize both
> osb_nfs_sync_lockres and nfs_sync_rwlock? Then we can let all
> lockres initialization look the same.
> Something like:
> static void ocfs2_nfs_sync_lock_init(struct ocfs2_super *osb)
> {
> 	ocfs2_nfs_sync_lock_res_init(&osb->osb_nfs_sync_lockres, osb);
> 	init_rwsem(&osb->nfs_sync_rwlock);
> }

No problem, will do it in v2.

Thanks,

Junxiao,.

>
> Thanks,
> Joseph
>
>>   
>>   void ocfs2_trim_fs_lock_res_init(struct ocfs2_super *osb)
>> @@ -2855,6 +2857,11 @@ int ocfs2_nfs_sync_lock(struct ocfs2_super *osb, int ex)
>>   	if (ocfs2_is_hard_readonly(osb))
>>   		return -EROFS;
>>   
>> +	if (ex)
>> +		down_write(&osb->nfs_sync_rwlock);
>> +	else
>> +		down_read(&osb->nfs_sync_rwlock);
>> +
>>   	if (ocfs2_mount_local(osb))
>>   		return 0;
>>   
>> @@ -2873,6 +2880,10 @@ void ocfs2_nfs_sync_unlock(struct ocfs2_super *osb, int ex)
>>   	if (!ocfs2_mount_local(osb))
>>   		ocfs2_cluster_unlock(osb, lockres,
>>   				     ex ? LKM_EXMODE : LKM_PRMODE);
>> +	if (ex)
>> +		up_write(&osb->nfs_sync_rwlock);
>> +	else
>> +		up_read(&osb->nfs_sync_rwlock);
>>   }
>>   
>>   int ocfs2_trim_fs_lock(struct ocfs2_super *osb,
>> @@ -3340,7 +3351,7 @@ int ocfs2_dlm_init(struct ocfs2_super *osb)
>>   local:
>>   	ocfs2_super_lock_res_init(&osb->osb_super_lockres, osb);
>>   	ocfs2_rename_lock_res_init(&osb->osb_rename_lockres, osb);
>> -	ocfs2_nfs_sync_lock_res_init(&osb->osb_nfs_sync_lockres, osb);
>> +	ocfs2_nfs_sync_lock_res_init(osb);
>>   	ocfs2_orphan_scan_lock_res_init(&osb->osb_orphan_scan.os_lockres, osb);
>>   
>>   	osb->cconn = conn;
>> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
>> index ee5d98516212..2dd71d626196 100644
>> --- a/fs/ocfs2/ocfs2.h
>> +++ b/fs/ocfs2/ocfs2.h
>> @@ -395,6 +395,7 @@ struct ocfs2_super
>>   	struct ocfs2_lock_res osb_super_lockres;
>>   	struct ocfs2_lock_res osb_rename_lockres;
>>   	struct ocfs2_lock_res osb_nfs_sync_lockres;
>> +	struct rw_semaphore nfs_sync_rwlock;
>>   	struct ocfs2_lock_res osb_trim_fs_lockres;
>>   	struct mutex obs_trim_fs_mutex;
>>   	struct ocfs2_dlm_debug *osb_dlm_debug;
>>