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Commit ba8b06e6 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Ensure that nfs_wb_page() waits for Pg_writeback to clear 

Neil Brown reports that he is seeing the BUG_ON(ret == 0) trigger in
nfs_page_async_flush. According to the trace in
     https://bugzilla.novell.com/show_bug.cgi?id=599628


the problem appears to be due to nfs_wb_page() not waiting for the
PG_writeback flag to clear.

There is a ditto problem in nfs_wb_page_cancel()

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 71d0a611

fs/nfs/write.c

+4 −15
Original line number Diff line number Diff line
@@ -1472,6 +1472,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page) 


	BUG_ON(!PageLocked(page));

	for (;;) {

		wait_on_page_writeback(page);

		req = nfs_page_find_request(page);

		if (req == NULL)

			break;
@@ -1506,31 +1507,19 @@ int nfs_wb_page(struct inode *inode, struct page *page) 
		.range_start = range_start,

		.range_end = range_end,

	};

	struct nfs_page *req;

	int need_commit;

	int ret;



	while(PagePrivate(page)) {

		wait_on_page_writeback(page);

		if (clear_page_dirty_for_io(page)) {

			ret = nfs_writepage_locked(page, &wbc);

			if (ret < 0)

				goto out_error;

		}

		req = nfs_find_and_lock_request(page);

		if (!req)

			break;

		if (IS_ERR(req)) {

			ret = PTR_ERR(req);

			goto out_error;

		}

		need_commit = test_bit(PG_CLEAN, &req->wb_flags);

		nfs_clear_page_tag_locked(req);

		if (need_commit) {

			ret = nfs_commit_inode(inode, FLUSH_SYNC);

		ret = sync_inode(inode, &wbc);

		if (ret < 0)

			goto out_error;

	}

	}

	return 0;

out_error:

	return ret;