NFSv4.2/pnfs: Use GFP_NOIO for layoutstat reporting in the writeback path

Prevent a potential deadlock.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index ba74b15..2a93bec 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -510,7 +510,8 @@
 	spin_unlock(&mirror->lock);
 
 	if (report)
-		pnfs_report_layoutstat(mirror->lseg->pls_layout->plh_inode);
+		pnfs_report_layoutstat(mirror->lseg->pls_layout->plh_inode,
+				GFP_KERNEL);
 }
 
 static void
@@ -538,7 +539,8 @@
 	spin_unlock(&mirror->lock);
 
 	if (report)
-		pnfs_report_layoutstat(mirror->lseg->pls_layout->plh_inode);
+		pnfs_report_layoutstat(mirror->lseg->pls_layout->plh_inode,
+				GFP_NOIO);
 }
 
 static void