netfs, 9p: Implement helpers for new write code

[linux-2.6-block.git] / fs / 9p / vfs_addr.c

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 5a943c122d831785864caf4817177f8fbe368cf5..07d03efdd594e8d17f3fcef1bb71e9db31b26582 100644 (file)
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -26,6 +26,40 @@
 #include "cache.h"
 #include "fid.h"
 
+/*
+ * Writeback calls this when it finds a folio that needs uploading.  This isn't
+ * called if writeback only has copy-to-cache to deal with.
+ */
+static void v9fs_begin_writeback(struct netfs_io_request *wreq)
+{
+       struct p9_fid *fid;
+
+       fid = v9fs_fid_find_inode(wreq->inode, true, INVALID_UID, true);
+       if (!fid) {
+               WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n",
+                         wreq->inode->i_ino);
+               return;
+       }
+
+       wreq->wsize = fid->clnt->msize - P9_IOHDRSZ;
+       if (fid->iounit)
+               wreq->wsize = min(wreq->wsize, fid->iounit);
+       wreq->netfs_priv = fid;
+       wreq->io_streams[0].avail = true;
+}
+
+/*
+ * Issue a subrequest to write to the server.
+ */
+static void v9fs_issue_write(struct netfs_io_subrequest *subreq)
+{
+       struct p9_fid *fid = subreq->rreq->netfs_priv;
+       int err, len;
+
+       len = p9_client_write(fid, subreq->start, &subreq->io_iter, &err);
+       netfs_write_subrequest_terminated(subreq, len ?: err, false);
+}
+
 static void v9fs_upload_to_server(struct netfs_io_subrequest *subreq)
 {
        struct p9_fid *fid = subreq->rreq->netfs_priv;
@@ -92,6 +126,14 @@ static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
                        rreq->origin == NETFS_UNBUFFERED_WRITE ||
                        rreq->origin == NETFS_DIO_WRITE);
 
+#if 0 // TODO: Cut over
+       if (rreq->origin == NETFS_WRITEBACK)
+               return 0; /* We don't get the write handle until we find we
+                          * have actually dirty data and not just
+                          * copy-to-cache data.
+                          */
+#endif
+
        if (file) {
                fid = file->private_data;
                if (!fid)
@@ -103,6 +145,10 @@ static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
                        goto no_fid;
        }
 
+       rreq->wsize = fid->clnt->msize - P9_IOHDRSZ;
+       if (fid->iounit)
+               rreq->wsize = min(rreq->wsize, fid->iounit);
+
        /* we might need to read from a fid that was opened write-only
         * for read-modify-write of page cache, use the writeback fid
         * for that */
@@ -131,6 +177,8 @@ const struct netfs_request_ops v9fs_req_ops = {
        .init_request           = v9fs_init_request,
        .free_request           = v9fs_free_request,
        .issue_read             = v9fs_issue_read,
+       .begin_writeback        = v9fs_begin_writeback,
+       .issue_write            = v9fs_issue_write,
        .create_write_requests  = v9fs_create_write_requests,
 };