[v5,41/51] pnfs: allow LD to ask to resend read through pnfs

Commit Message

Thomas Haynes Jan. 22, 2015, 11:36 p.m. UTC

From: Peng Tao <[e-mail]>

If current IO cannot be completed due to some transient errors,
LD may want to ask generic layer to resend the request through
pnfs again.

Signed-off-by: Peng Tao <[e-mail]>
Signed-off-by: Tom Haynes <[e-mail]>
---
 fs/nfs/pnfs.c | 15 ++++++++++++++-
 fs/nfs/pnfs.h |  2 ++
 2 files changed, 16 insertions(+), 1 deletion(-)

Patch

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index b822b17..685af4f 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1880,15 +1880,28 @@  pnfs_try_to_read_data(struct nfs_pgio_header *hdr,
 	return trypnfs;
 }
 
+/* Resend all requests through pnfs. */
+int pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr)
+{
+	struct nfs_pageio_descriptor pgio;
+
+	nfs_pageio_init_read(&pgio, hdr->inode, false, hdr->completion_ops);
+	return nfs_pageio_resend(&pgio, hdr);
+}
+EXPORT_SYMBOL_GPL(pnfs_read_resend_pnfs);
+
 static void
 pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
 {
 	const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
 	struct pnfs_layout_segment *lseg = desc->pg_lseg;
 	enum pnfs_try_status trypnfs;
+	int err = 0;
 
 	trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg);
-	if (trypnfs == PNFS_NOT_ATTEMPTED)
+	if (trypnfs == PNFS_TRY_AGAIN)
+		err = pnfs_read_resend_pnfs(hdr);
+	if (trypnfs == PNFS_NOT_ATTEMPTED || err)
 		pnfs_read_through_mds(desc, hdr);
 }
 
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 3d4a83b..6d2b544 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -72,6 +72,7 @@  struct pnfs_layout_segment {
 enum pnfs_try_status {
 	PNFS_ATTEMPTED     = 0,
 	PNFS_NOT_ATTEMPTED = 1,
+	PNFS_TRY_AGAIN     = 2,
 };
 
 #ifdef CONFIG_NFS_V4_1
@@ -268,6 +269,7 @@  int _pnfs_return_layout(struct inode *);
 int pnfs_commit_and_return_layout(struct inode *);
 void pnfs_ld_write_done(struct nfs_pgio_header *);
 void pnfs_ld_read_done(struct nfs_pgio_header *);
+int pnfs_read_resend_pnfs(struct nfs_pgio_header *);
 struct pnfs_layout_segment *pnfs_update_layout(struct inode *ino,
 					       struct nfs_open_context *ctx,
 					       loff_t pos,