On 07/12/2012 11:43 AM, J. Bruce Fields wrote:
> On Fri, May 25, 2012 at 06:38:50PM +0400, Stanislav Kinsbursky wrote:
>> v2: dl_recall_lru list is used for delegations collect because it's modified
>> both in unhash_delegation() and nfsd_break_one_deleg().
>>
>> This patch adds recall_lock hold to nfsd_forget_delegations() to protect
>> nfsd_process_n_delegations() call.
>> Also, looks like it would be better to collect delegations to some local
>> on-stack list, and then unhash collected list. This split allows to
>> simplify locking, because delegation traversing is protected by recall_lock,
>> when delegation unhash is protected by client_mutex.
>
> Thanks, applying for 3.6 (assuming Bryan doesn't have any objection).
Nope, I don't have any objections.
- Bryan
>
> --b.
>
>>
>> Signed-off-by: Stanislav Kinsbursky <skinsbur...@parallels.com>
>> ---
>> fs/nfsd/nfs4state.c | 21 +++++++++++++++++----
>> 1 files changed, 17 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 21266c7..3d6848b 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -4694,7 +4694,7 @@ void nfsd_forget_openowners(u64 num)
>> printk(KERN_INFO "NFSD: Forgot %d open owners", count);
>> }
>>
>> -int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct
>> nfs4_delegation *))
>> +int nfsd_process_n_delegations(u64 num, struct list_head *list)
>> {
>> int i, count = 0;
>> struct nfs4_file *fp, *fnext;
>> @@ -4703,7 +4703,7 @@ int nfsd_process_n_delegations(u64 num, void
>> (*deleg_func)(struct nfs4_delegatio
>> for (i = 0; i < FILE_HASH_SIZE; i++) {
>> list_for_each_entry_safe(fp, fnext, &file_hashtbl[i], fi_hash) {
>> list_for_each_entry_safe(dp, dnext,
>> &fp->fi_delegations, dl_perfile) {
>> - deleg_func(dp);
>> + list_move(&dp->dl_recall_lru, list);
>> if (++count == num)
>> return count;
>> }
>> @@ -4716,9 +4716,16 @@ int nfsd_process_n_delegations(u64 num, void
>> (*deleg_func)(struct nfs4_delegatio
>> void nfsd_forget_delegations(u64 num)
>> {
>> unsigned int count;
>> + LIST_HEAD(victims);
>> + struct nfs4_delegation *dp, *dnext;
>> +
>> + spin_lock(&recall_lock);
>> + count = nfsd_process_n_delegations(num, &victims);
>> + spin_unlock(&recall_lock);
>>
>> nfs4_lock_state();
>> - count = nfsd_process_n_delegations(num, unhash_delegation);
>> + list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru)
>> + unhash_delegation(dp);
>> nfs4_unlock_state();
>>
>> printk(KERN_INFO "NFSD: Forgot %d delegations", count);
>> @@ -4727,10 +4734,16 @@ void nfsd_forget_delegations(u64 num)
>> void nfsd_recall_delegations(u64 num)
>> {
>> unsigned int count;
>> + LIST_HEAD(victims);
>> + struct nfs4_delegation *dp, *dnext;
>>
>> nfs4_lock_state();
>> spin_lock(&recall_lock);
>> - count = nfsd_process_n_delegations(num, nfsd_break_one_deleg);
>> + count = nfsd_process_n_delegations(num, &victims);
>> + list_for_each_entry_safe(dp, dnext, &victims, dl_recall_lru) {
>> + list_del(&dp->dl_recall_lru);
>> + nfsd_break_one_deleg(dp);
>> + }
>> spin_unlock(&recall_lock);
>> nfs4_unlock_state();
>>
>>
>> --
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