NFS: merge _full and _partial read rpc_ops

Decouple nfs_pgio_header and nfs_read_data, and have (possibly
multiple) nfs_read_datas each take a refcount on nfs_pgio_header.

For the moment keeps nfs_read_header as a way to preallocate a single
nfs_read_data with the nfs_pgio_header.  The code doesn't need this,
and would be prettier without, but given the amount of churn I am
already introducing I didn't want to play with tuning new mempools.

This also fixes bug in pnfs_ld_handle_read_error.  In the case of
desc->pg_bsize < PAGE_CACHE_SIZE, the pages list was empty, causing
replay attempt to do nothing.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d349bd4c48db..cd4c038135a7 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -39,6 +39,30 @@ bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount)
         return p->pagevec != NULL;
 }
 
+void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
+                       struct nfs_pgio_header *hdr,
+                       void (*release)(struct nfs_pgio_header *hdr))
+{
+        hdr->req = nfs_list_entry(desc->pg_list.next);
+        hdr->inode = desc->pg_inode;
+        hdr->cred = hdr->req->wb_context->cred;
+        hdr->io_start = req_offset(hdr->req);
+        hdr->good_bytes = desc->pg_count;
+        hdr->release = release;
+}
+
+void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
+{
+        spin_lock(&hdr->lock);
+        if (pos < hdr->io_start + hdr->good_bytes) {
+                set_bit(NFS_IOHDR_ERROR, &hdr->flags);
+                clear_bit(NFS_IOHDR_EOF, &hdr->flags);
+                hdr->good_bytes = pos - hdr->io_start;
+                hdr->error = error;
+        }
+        spin_unlock(&hdr->lock);
+}
+
 static inline struct nfs_page *
 nfs_page_alloc(void)
 {