X-Git-Url: https://git.whamcloud.com/?a=blobdiff_plain;f=lustre%2Fobdfs%2Frw.c;h=558cfedf6ee3661592171e7558e065154fc62c60;hb=86ada49822948e9cf3a8488b3297f111bcaef72e;hp=2be005b04570dcbf9d471ff6b71f662302235432;hpb=8688197f18b85befc95d8bb812c71cc6bec47284;p=fs%2Flustre-release.git

diff --git a/lustre/obdfs/rw.c b/lustre/obdfs/rw.c
index 2be005b..558cfed 100644
--- a/lustre/obdfs/rw.c
+++ b/lustre/obdfs/rw.c
@@ -47,10 +47,10 @@ int obdfs_brw(struct inode *dir, int rw, struct page *page, int create)
 int obdfs_readpage(struct dentry *dentry, struct page *page)
 {
 	struct inode *inode = dentry->d_inode;
-	int rc;
+	struct obdfs_wreq *wreq;
+	int rc = 0;
 
         ENTRY;
-	/* XXX flush stuff */
 	PDEBUG(page, "READ");
 	rc =  iops(inode)->o_brw(READ, iid(inode),inode, page, 0);
 	if (rc == PAGE_SIZE ) {
@@ -60,10 +60,124 @@ int obdfs_readpage(struct dentry *dentry, struct page *page)
 	PDEBUG(page, "READ");
 	if ( rc == PAGE_SIZE ) 
 		rc = 0;
+	} 
+	EXIT;
 	return rc;
+}
+
+static kmem_cache_t *obdfs_wreq_cachep;
+
+int obdfs_init_wreqcache(void)
+{
+	/* XXX need to free this somewhere? */
+	ENTRY;
+	obdfs_wreq_cachep = kmem_cache_create("obdfs_wreq",
+					      sizeof(struct obdfs_wreq),
+					      0, SLAB_HWCACHE_ALIGN,
+					      NULL, NULL);
+	if (obdfs_wreq_cachep == NULL) {
+		EXIT;
+		return -ENOMEM;
+	}
+	EXIT;
+	return 0;
+}
+
+/*
+ * Find a specific page in the page cache.  If it is found, we return
+ * the write request struct associated with it, if not found return NULL.
+ */
+static struct obdfs_wreq *
+obdfs_find_in_page_cache(struct inode *inode, struct page *page)
+{
+	struct list_head *list_head = &OBD_LIST(inode);
+	struct obdfs_wreq *head, *wreq;
+
+	ENTRY;
+	CDEBUG(D_INODE, "looking for inode %ld page %p\n", inode->i_ino, page);
+	if (list_empty(list_head)) {
+		CDEBUG(D_INODE, "empty list\n");
+		EXIT;
+		return NULL;
+	}
+	wreq = head = WREQ(list_head->next);
+	do {
+		CDEBUG(D_INODE, "checking page %p\n", wreq->wb_page);
+		if (wreq->wb_page == page) {
+			CDEBUG(D_INODE, "found page %p in list\n", page);
+			EXIT;
+			return wreq;
+		}
+	} while ((wreq = WB_NEXT(wreq)) != head);
 
+	EXIT;
+	return NULL;
 }
 
+
+/*
+ * Remove a writeback request from a list
+ */
+static inline int
+obdfs_remove_from_page_cache(struct obdfs_wreq *wreq)
+{
+	struct inode *inode = wreq->wb_inode;
+	struct page *page = wreq->wb_page;
+	int rc;
+
+	ENTRY;
+	CDEBUG(D_INODE, "removing inode %ld page %p, wreq: %p\n",
+	       inode->i_ino, page, wreq);
+	rc = iops(inode)->o_brw(WRITE, iid(inode), inode, page, 1);
+	/* XXX probably should handle error here somehow.  I think that
+	 *     ext2 also does the same thing - discard write even if error?
+	 */
+	put_page(page);
+        list_del(&wreq->wb_list);
+	kmem_cache_free(obdfs_wreq_cachep, wreq);
+
+	EXIT;
+	return rc;
+}
+
+/*
+ * Add a page to the write request cache list for later writing
+ */
+static int
+obdfs_add_to_page_cache(struct inode *inode, struct page *page)
+{
+	struct obdfs_wreq *wreq;
+
+	ENTRY;
+	wreq = kmem_cache_alloc(obdfs_wreq_cachep, SLAB_KERNEL);
+	CDEBUG(D_INODE, "adding inode %ld page %p, wreq: %p\n",
+	       inode->i_ino, page, wreq);
+	if (!wreq) {
+		EXIT;
+		return -ENOMEM;
+	}
+	memset(wreq, 0, sizeof(*wreq)); 
+
+	wreq->wb_page = page;
+	wreq->wb_inode = inode;
+
+	get_page(wreq->wb_page);
+	list_add(&wreq->wb_list, &OBD_LIST(inode));
+
+	/* For testing purposes, we write out the page here.
+	 * In the future, a flush daemon will write out the page.
+	 */
+	wreq = obdfs_find_in_page_cache(inode, page);
+	if (!wreq) {
+		CDEBUG(D_INODE, "XXXX Can't find page after adding it!!!\n");
+		return -EINVAL;
+	} else
+		return obdfs_remove_from_page_cache(wreq);
+
+	return 0;
+}
+
+
 /* returns the page unlocked, but with a reference */
 int obdfs_writepage(struct dentry *dentry, struct page *page)
 {
@@ -73,10 +187,10 @@ int obdfs_writepage(struct dentry *dentry, struct page *page)
         ENTRY;
 	PDEBUG(page, "WRITEPAGE");
 	/* XXX flush stuff */
+	rc = obdfs_add_to_page_cache(inode, page);
 
-	rc = iops(inode)->o_brw(WRITE, iid(inode), inode, page, 1);
-
-	SetPageUptodate(page);
+	if (!rc)
+		SetPageUptodate(page);
 	PDEBUG(page,"WRITEPAGE");
 	return rc;
 }