patch 14/38: CLIENT: add ->setup_read() nfs_rpc_op for async read, part 1

Kendrick M. Smith
2002-08-13T22:59:53Z

This is a nontrivial change to the NFS client.

Synchronous READ operations are currently done via the ->read() nfs_rpc_op.
Therefore, the synchronous READ path can easily be adapted for NFSv4. On
the other hand, the asynchronous READ path contains several NFSv3-specific
features, which make it difficult to adapt for NFSv4.

In this patch and the next, we modify the async READ path to be
version-agnostic. This patch just changes the 'struct nfs_read_data'
so that the v2- and v3-specific parts are moved into a private area,
with room for a v4-specific part in parallel. None of the logic is
changed.

--- old/fs/nfs/read.c Wed Jul 24 16:03:17 2002
+++ new/fs/nfs/read.c Sat Aug 10 22:20:39 2002
@@ -38,11 +38,18 @@ struct nfs_read_data {
struct rpc_task task;
struct inode *inode;
struct rpc_cred *cred;
- struct nfs_readargs args; /* XDR argument struct */
- struct nfs_readres res; /* ... and result struct */
struct nfs_fattr fattr; /* fattr storage */
struct list_head pages; /* Coalesced read requests */
struct page *pagevec[NFS_READ_MAXIOV];
+ union {
+ struct {
+ struct nfs_readargs args;
+ struct nfs_readres res;
+ } v3; /* also v2 */
+#ifdef CONFIG_NFS_V4
+ /* NFSv4 data will come here... */
+#endif
+ } u;
};

/*
@@ -64,7 +71,6 @@ static __inline__ struct nfs_read_data *
if (p) {
memset(p, 0, sizeof(*p));
INIT_LIST_HEAD(&p->pages);
- p->args.pages = p->pagevec;
}
return p;
}
@@ -194,7 +200,7 @@ nfs_read_rpcsetup(struct list_head *head
struct page **pages;
unsigned int count;

- pages = data->args.pages;
+ pages = data->pagevec;
count = 0;
while (!list_empty(head)) {
struct nfs_page *req = nfs_list_entry(head->next);
@@ -206,13 +212,14 @@ nfs_read_rpcsetup(struct list_head *head
req = nfs_list_entry(data->pages.next);
data->inode = req->wb_inode;
data->cred = req->wb_cred;
- data->args.fh = NFS_FH(req->wb_inode);
- data->args.offset = page_offset(req->wb_page) + req->wb_offset;
- data->args.pgbase = req->wb_offset;
- data->args.count = count;
- data->res.fattr = &data->fattr;
- data->res.count = count;
- data->res.eof = 0;
+ data->u.v3.args.fh = NFS_FH(req->wb_inode);
+ data->u.v3.args.offset = page_offset(req->wb_page) + req->wb_offset;
+ data->u.v3.args.pgbase = req->wb_offset;
+ data->u.v3.args.pages = pages;
+ data->u.v3.args.count = count;
+ data->u.v3.res.fattr = &data->fattr;
+ data->u.v3.res.count = count;
+ data->u.v3.res.eof = 0;
}

static void
@@ -264,8 +271,8 @@ nfs_pagein_one(struct list_head *head, s
#else
msg.rpc_proc = NFSPROC_READ;
#endif
- msg.rpc_argp = &data->args;
- msg.rpc_resp = &data->res;
+ msg.rpc_argp = &data->u.v3.args;
+ msg.rpc_resp = &data->u.v3.res;
msg.rpc_cred = data->cred;

/* Start the async call */
@@ -273,8 +280,8 @@ nfs_pagein_one(struct list_head *head, s
task->tk_pid,
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
- (unsigned int)data->args.count,
- (unsigned long long)data->args.offset);
+ (unsigned int)data->u.v3.args.count,
+ (unsigned long long)data->u.v3.args.offset);

rpc_clnt_sigmask(clnt, &oldset);
rpc_call_setup(task, &msg, 0);
@@ -404,7 +411,7 @@ nfs_readpage_result(struct rpc_task *tas
{
struct nfs_read_data *data = (struct nfs_read_data *) task->tk_calldata;
struct inode *inode = data->inode;
- unsigned int count = data->res.count;
+ unsigned int count = data->u.v3.res.count;

dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
task->tk_pid, task->tk_status);