NFS: Use an atomic_long_t to count the number of commits

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/inode.c

@@ -2012,7 +2012,7 @@ static void init_once(void *foo)
 	INIT_LIST_HEAD(&nfsi->access_cache_inode_lru);
 	INIT_LIST_HEAD(&nfsi->commit_info.list);
 	atomic_long_set(&nfsi->nrequests, 0);
-	nfsi->commit_info.ncommit = 0;
+	atomic_long_set(&nfsi->commit_info.ncommit, 0);
 	atomic_set(&nfsi->commit_info.rpcs_out, 0);
 	init_rwsem(&nfsi->rmdir_sem);
 	mutex_init(&nfsi->commit_mutex);

fs/nfs/write.c

@@ -857,7 +857,7 @@ nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
 {
 	set_bit(PG_CLEAN, &req->wb_flags);
 	nfs_list_add_request(req, dst);
-	cinfo->mds->ncommit++;
+	atomic_long_inc(&cinfo->mds->ncommit);
 }
 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 
@@ -903,7 +903,7 @@ nfs_request_remove_commit_list(struct nfs_page *req,
 	if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 		return;
 	nfs_list_remove_request(req);
-	cinfo->mds->ncommit--;
+	atomic_long_dec(&cinfo->mds->ncommit);
 }
 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 
@@ -1017,7 +1017,7 @@ out:
 unsigned long
 nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
 {
-	return cinfo->mds->ncommit;
+	return atomic_long_read(&cinfo->mds->ncommit);
 }
 
 /* NFS_I(cinfo->inode)->commit_mutex held by caller */
@@ -1057,8 +1057,10 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst,
 {
 	int ret = 0;
 
+	if (!atomic_long_read(&cinfo->mds->ncommit))
+		return 0;
 	mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
-	if (cinfo->mds->ncommit > 0) {
+	if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
 		const int max = INT_MAX;
 
 		ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
@@ -1890,7 +1892,7 @@ int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 	int ret = 0;
 
 	/* no commits means nothing needs to be done */
-	if (!nfsi->commit_info.ncommit)
+	if (!atomic_long_read(&nfsi->commit_info.ncommit))
 		return ret;
 
 	if (wbc->sync_mode == WB_SYNC_NONE) {

include/linux/nfs_xdr.h

@@ -1476,7 +1476,7 @@ struct nfs_pgio_header {
 
 struct nfs_mds_commit_info {
 	atomic_t rpcs_out;
-	unsigned long		ncommit;
+	atomic_long_t		ncommit;
 	struct list_head	list;
 };