[Ocfs2-devel] [PATCH v2] ocfs2/dlm: fix race between convert and recovery
Junxiao Bi
junxiao.bi at oracle.com
Sun Sep 20 00:20:17 PDT 2015
Reviewed-by: Junxiao Bi <junxiao.bi at oracle.com>
> 在 2015年9月18日，下午7:25，Joseph Qi <joseph.qi at huawei.com> 写道：
>
> There is a race window between dlmconvert_remote and
> dlm_move_lockres_to_recovery_list, which will cause a lock with
> OCFS2_LOCK_BUSY in grant list, thus system hangs.
>
> dlmconvert_remote
> {
> spin_lock(&res->spinlock);
> list_move_tail(&lock->list, &res->converting);
> lock->convert_pending = 1;
> spin_unlock(&res->spinlock);
>
> status = dlm_send_remote_convert_request();
>>>>>>> race window, master has queued ast and return DLM_NORMAL,
> and then down before sending ast.
> this node detects master down and calls
> dlm_move_lockres_to_recovery_list, which will revert the
> lock to grant list.
> Then OCFS2_LOCK_BUSY won't be cleared as new master won't
> send ast any more because it thinks already be authorized.
>
> spin_lock(&res->spinlock);
> lock->convert_pending = 0;
> if (status != DLM_NORMAL)
> dlm_revert_pending_convert(res, lock);
> spin_unlock(&res->spinlock);
> }
>
> In this case, just leave it in convert list and new master will take care
> of it after recovery. And if convert request returns other than
> DLM_NORMAL, convert thread will do the revert itself. So remove the
> revert logic in dlm_move_lockres_to_recovery_list.
>
> changelog since v1:
> Clean up convert_pending since it is now useless.
>
> Signed-off-by: Joseph Qi <joseph.qi at huawei.com>
> Reported-by: Yiwen Jiang <jiangyiwen at huawei.com>
> Cc: <stable at vger.kernel.org>
> ---
> fs/ocfs2/dlm/dlmcommon.h | 1 -
> fs/ocfs2/dlm/dlmconvert.c | 2 --
> fs/ocfs2/dlm/dlmdebug.c | 7 +++----
> fs/ocfs2/dlm/dlmlock.c | 1 -
> fs/ocfs2/dlm/dlmrecovery.c | 10 +---------
> 5 files changed, 4 insertions(+), 17 deletions(-)
>
> diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
> index e88ccf8..25853d7 100644
> --- a/fs/ocfs2/dlm/dlmcommon.h
> +++ b/fs/ocfs2/dlm/dlmcommon.h
> @@ -369,7 +369,6 @@ struct dlm_lock
> struct dlm_lockstatus *lksb;
> unsigned ast_pending:1,
> bast_pending:1,
> - convert_pending:1,
> lock_pending:1,
> cancel_pending:1,
> unlock_pending:1,
> diff --git a/fs/ocfs2/dlm/dlmconvert.c b/fs/ocfs2/dlm/dlmconvert.c
> index e36d63f..82ba8d5 100644
> --- a/fs/ocfs2/dlm/dlmconvert.c
> +++ b/fs/ocfs2/dlm/dlmconvert.c
> @@ -291,7 +291,6 @@ enum dlm_status dlmconvert_remote(struct dlm_ctxt *dlm,
> /* move lock to local convert queue */
> /* do not alter lock refcount. switching lists. */
> list_move_tail(&lock->list, &res->converting);
> - lock->convert_pending = 1;
> lock->ml.convert_type = type;
>
> if (flags & LKM_VALBLK) {
> @@ -315,7 +314,6 @@ enum dlm_status dlmconvert_remote(struct dlm_ctxt *dlm,
>
> spin_lock(&res->spinlock);
> res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
> - lock->convert_pending = 0;
> /* if it failed, move it back to granted queue */
> if (status != DLM_NORMAL) {
> if (status != DLM_NOTQUEUED)
> diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
> index 8251360..710e94c 100644
> --- a/fs/ocfs2/dlm/dlmdebug.c
> +++ b/fs/ocfs2/dlm/dlmdebug.c
> @@ -77,7 +77,7 @@ static void __dlm_print_lock(struct dlm_lock *lock)
>
> printk(" type=%d, conv=%d, node=%u, cookie=%u:%llu, "
> "ref=%u, ast=(empty=%c,pend=%c), bast=(empty=%c,pend=%c), "
> - "pending=(conv=%c,lock=%c,cancel=%c,unlock=%c)\n",
> + "pending=(lock=%c,cancel=%c,unlock=%c)\n",
> lock->ml.type, lock->ml.convert_type, lock->ml.node,
> dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
> dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
> @@ -86,7 +86,6 @@ static void __dlm_print_lock(struct dlm_lock *lock)
> (lock->ast_pending ? 'y' : 'n'),
> (list_empty(&lock->bast_list) ? 'y' : 'n'),
> (lock->bast_pending ? 'y' : 'n'),
> - (lock->convert_pending ? 'y' : 'n'),
> (lock->lock_pending ? 'y' : 'n'),
> (lock->cancel_pending ? 'y' : 'n'),
> (lock->unlock_pending ? 'y' : 'n'));
> @@ -502,7 +501,7 @@ static int dump_lock(struct dlm_lock *lock, int list_type, char *buf, int len)
>
> #define DEBUG_LOCK_VERSION 1
> spin_lock(&lock->spinlock);
> - out = snprintf(buf, len, "LOCK:%d,%d,%d,%d,%d,%d:%lld,%d,%d,%d,%d,%d,"
> + out = snprintf(buf, len, "LOCK:%d,%d,%d,%d,%d,%d:%lld,%d,%d,%d,%d,"
> "%d,%d,%d,%d\n",
> DEBUG_LOCK_VERSION,
> list_type, lock->ml.type, lock->ml.convert_type,
> @@ -512,7 +511,7 @@ static int dump_lock(struct dlm_lock *lock, int list_type, char *buf, int len)
> !list_empty(&lock->ast_list),
> !list_empty(&lock->bast_list),
> lock->ast_pending, lock->bast_pending,
> - lock->convert_pending, lock->lock_pending,
> + lock->lock_pending,
> lock->cancel_pending, lock->unlock_pending,
> atomic_read(&lock->lock_refs.refcount));
> spin_unlock(&lock->spinlock);
> diff --git a/fs/ocfs2/dlm/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c
> index 66c2a49..857dd15 100644
> --- a/fs/ocfs2/dlm/dlmlock.c
> +++ b/fs/ocfs2/dlm/dlmlock.c
> @@ -411,7 +411,6 @@ static void dlm_init_lock(struct dlm_lock *newlock, int type,
> newlock->ml.cookie = cpu_to_be64(cookie);
> newlock->ast_pending = 0;
> newlock->bast_pending = 0;
> - newlock->convert_pending = 0;
> newlock->lock_pending = 0;
> newlock->unlock_pending = 0;
> newlock->cancel_pending = 0;
> diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
> index 3d90ad7..2402ef7 100644
> --- a/fs/ocfs2/dlm/dlmrecovery.c
> +++ b/fs/ocfs2/dlm/dlmrecovery.c
> @@ -2062,15 +2062,7 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
> queue = dlm_list_idx_to_ptr(res, i);
> list_for_each_entry_safe(lock, next, queue, list) {
> dlm_lock_get(lock);
> - if (lock->convert_pending) {
> - /* move converting lock back to granted */
> - BUG_ON(i != DLM_CONVERTING_LIST);
> - mlog(0, "node died with convert pending "
> - "on %.*s. move back to granted list.\n",
> - res->lockname.len, res->lockname.name);
> - dlm_revert_pending_convert(res, lock);
> - lock->convert_pending = 0;
> - } else if (lock->lock_pending) {
> + if (lock->lock_pending) {
> /* remove pending lock requests completely */
> BUG_ON(i != DLM_BLOCKED_LIST);
> mlog(0, "node died with lock pending "
> --
> 1.8.4.3
>
>
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