From c829013dca33110d57c7f625443b716bd7a17671 Mon Sep 17 00:00:00 2001
From: Peng Tao <tao.peng@primarydata.com>
Date: Mon, 1 Dec 2014 08:22:18 +0800
Subject: [PATCH] nfs41: add NFS_LAYOUT_RETRY_LAYOUTGET to layout header flags

Use it to indicate that LD wants to retry layoutget. LD can set
it whenever it wants the common pnfs code to return and retry
pnfs path through a new layout.

The bit gets cleared when client does a new layoutget, when client
closes the file (ROC case), or when kernel needs to evict the inode
(non-ROC case).

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
---
 fs/nfs/pnfs.c |  3 +++
 fs/nfs/pnfs.h | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 108a619861e5..893f6b5afe6a 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -615,6 +615,7 @@ pnfs_destroy_layout(struct nfs_inode *nfsi)
 		pnfs_get_layout_hdr(lo);
 		pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
 		pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
+		pnfs_clear_retry_layoutget(lo);
 		spin_unlock(&nfsi->vfs_inode.i_lock);
 		pnfs_free_lseg_list(&tmp_list);
 		pnfs_put_layout_hdr(lo);
@@ -1066,6 +1067,7 @@ bool pnfs_roc(struct inode *ino)
 	if (!lo || !test_and_clear_bit(NFS_LAYOUT_ROC, &lo->plh_flags) ||
 	    test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
 		goto out_nolayout;
+	pnfs_clear_retry_layoutget(lo);
 	list_for_each_entry_safe(lseg, tmp, &lo->plh_segs, pls_list)
 		if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
 			mark_lseg_invalid(lseg, &tmp_list);
@@ -1491,6 +1493,7 @@ lookup_again:
 		arg.length = PAGE_CACHE_ALIGN(arg.length);
 
 	lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
+	pnfs_clear_retry_layoutget(lo);
 	atomic_dec(&lo->plh_outstanding);
 out_put_layout_hdr:
 	if (first) {
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 080bf90498d4..fed6ae067acb 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -99,6 +99,7 @@ enum {
 	NFS_LAYOUT_RETURN_BEFORE_CLOSE,	/* Return this layout before close */
 	NFS_LAYOUT_INVALID_STID,	/* layout stateid id is invalid */
 	NFS_LAYOUT_FIRST_LAYOUTGET,	/* Serialize first layoutget */
+	NFS_LAYOUT_RETRY_LAYOUTGET,	/* Retry layoutget */
 };
 
 enum layoutdriver_policy_flags {
@@ -350,6 +351,23 @@ nfs4_get_deviceid(struct nfs4_deviceid_node *d)
 	return d;
 }
 
+static inline void pnfs_set_retry_layoutget(struct pnfs_layout_hdr *lo)
+{
+	if (!test_and_set_bit(NFS_LAYOUT_RETRY_LAYOUTGET, &lo->plh_flags))
+		atomic_inc(&lo->plh_refcount);
+}
+
+static inline void pnfs_clear_retry_layoutget(struct pnfs_layout_hdr *lo)
+{
+	if (test_and_clear_bit(NFS_LAYOUT_RETRY_LAYOUTGET, &lo->plh_flags))
+		atomic_dec(&lo->plh_refcount);
+}
+
+static inline bool pnfs_should_retry_layoutget(struct pnfs_layout_hdr *lo)
+{
+	return test_bit(NFS_LAYOUT_RETRY_LAYOUTGET, &lo->plh_flags);
+}
+
 static inline struct pnfs_layout_segment *
 pnfs_get_lseg(struct pnfs_layout_segment *lseg)
 {