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Commit a6305ddb authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Fix a race with the new commit code 



This patch fixes a race which occurs due to the fact that we release the
PG_writeback flag while still holding the nfs_page locked.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent b80c3cb6

fs/nfs/write.c

+10 −7
Original line number Diff line number Diff line
@@ -201,6 +201,7 @@ static int nfs_set_page_writeback(struct page *page) 
		struct inode *inode = page->mapping->host;

		struct nfs_server *nfss = NFS_SERVER(inode);



		page_cache_get(page);

		if (atomic_long_inc_return(&nfss->writeback) >

				NFS_CONGESTION_ON_THRESH) {

			set_bdi_congested(&nfss->backing_dev_info,
@@ -216,6 +217,7 @@ static void nfs_end_page_writeback(struct page *page) 
	struct nfs_server *nfss = NFS_SERVER(inode);



	end_page_writeback(page);

	page_cache_release(page);

	if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)

		clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);

}
@@ -665,6 +667,7 @@ static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page, 
	/* Update file length */

	nfs_grow_file(page, offset, count);

	nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);

	nfs_mark_request_dirty(req);

	nfs_clear_page_tag_locked(req);

	return 0;

}
@@ -749,13 +752,12 @@ int nfs_updatepage(struct file *file, struct page *page, 


static void nfs_writepage_release(struct nfs_page *req)

{

	struct page *page = req->wb_page;



	if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {

		nfs_end_page_writeback(req->wb_page);

	if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req))

		nfs_inode_remove_request(req);

	} else

		nfs_end_page_writeback(req->wb_page);

	nfs_clear_page_tag_locked(req);

	nfs_end_page_writeback(page);

}



static int flush_task_priority(int how)
@@ -847,9 +849,11 @@ static int nfs_write_rpcsetup(struct nfs_page *req, 
 */

static void nfs_redirty_request(struct nfs_page *req)

{

	struct page *page = req->wb_page;



	nfs_mark_request_dirty(req);

	nfs_end_page_writeback(req->wb_page);

	nfs_clear_page_tag_locked(req);

	nfs_end_page_writeback(page);

}



/*
@@ -1084,16 +1088,15 @@ static void nfs_writeback_release_full(void *calldata) 
		if (nfs_write_need_commit(data)) {

			memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));

			nfs_mark_request_commit(req);

			nfs_end_page_writeback(page);

			dprintk(" marked for commit\n");

			goto next;

		}

		dprintk(" OK\n");

remove_request:

		nfs_end_page_writeback(page);

		nfs_inode_remove_request(req);

	next:

		nfs_clear_page_tag_locked(req);

		nfs_end_page_writeback(page);

	}

	nfs_writedata_release(calldata);

}