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authorBenjamin Coddington <bcodding@redhat.com>2017-04-11 12:50:10 -0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2017-04-21 10:45:01 -0400
commit7d6ddf88c4db372689c8aa65ea652d0514d66c06 (patch)
tree8fb586be995259ff4c98a01ee9ed183b107195b5 /fs/nfs/pagelist.c
parent50f2112cf7a3e62a8d33838eb205d5fef306457a (diff)
NFS: Add an iocounter wait function for async RPC tasks
By sleeping on a new NFS Unlock-On-Close waitqueue, rpc tasks may wait for a lock context's iocounter to reach zero. The rpc waitqueue is only woken when the open_context has the NFS_CONTEXT_UNLOCK flag set in order to mitigate spurious wake-ups for any iocounter reaching zero. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/pagelist.c')
-rw-r--r--fs/nfs/pagelist.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index f53610672f03..ad92b401326c 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -102,6 +102,35 @@ nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
TASK_KILLABLE);
}
+/**
+ * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
+ * to complete
+ * @task: the rpc_task that should wait
+ * @l_ctx: nfs_lock_context with io_counter to check
+ *
+ * Returns true if there is outstanding I/O to wait on and the
+ * task has been put to sleep.
+ */
+bool
+nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
+{
+ struct inode *inode = d_inode(l_ctx->open_context->dentry);
+ bool ret = false;
+
+ if (atomic_read(&l_ctx->io_count) > 0) {
+ rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
+ ret = true;
+ }
+
+ if (atomic_read(&l_ctx->io_count) == 0) {
+ rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
+ ret = false;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
+
/*
* nfs_page_group_lock - lock the head of the page group
* @req - request in group that is to be locked
@@ -385,8 +414,11 @@ static void nfs_clear_request(struct nfs_page *req)
req->wb_page = NULL;
}
if (l_ctx != NULL) {
- if (atomic_dec_and_test(&l_ctx->io_count))
+ if (atomic_dec_and_test(&l_ctx->io_count)) {
wake_up_atomic_t(&l_ctx->io_count);
+ if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
+ rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
+ }
nfs_put_lock_context(l_ctx);
req->wb_lock_context = NULL;
}