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, 8 insertions, 2 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 0faba4cb531d..90b00ce42cbe 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -319,10 +319,16 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
                 bytes = min(rsize,count);
 
                 result = -ENOMEM;
-                rhdr = nfs_readhdr_alloc(nfs_page_array_len(pgbase, bytes));
+                rhdr = nfs_readhdr_alloc();
                 if (unlikely(!rhdr))
                         break;
-                data = &rhdr->rpc_data;
+                data = nfs_readdata_alloc(&rhdr->header, nfs_page_array_len(pgbase, bytes));
+                if (!data) {
+                        nfs_readhdr_free(&rhdr->header);
+                        break;
+                }
+                data->header = &rhdr->header;
+                atomic_inc(&data->header->refcnt);
                 pages = &data->pages;
 
                 down_read(&current->mm->mmap_sem);