pnfs: allow LD to ask to resend read through pnfs

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 <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index b822b1749643dcf485b5b2dd94eda17093e53676..685af4fb39cabd1f1d0c2f0187e0a495aab68844 100644 (file)
--- 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 a0ab81cc9cf3724441fa431e4e0f21ba0a05b167..84c25cd476f85d8bfc905bd139fb89ebe4a19a69 100644 (file)
--- 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,