}
#endif
+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;
+}
+
/* returns the page unlocked, but with a reference */
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 ) {
- SetPageUptodate(page);
- UnlockPage(page);
+ wreq = obdfs_find_in_page_cache(inode, page);
+ if (!wreq) {
+ PDEBUG(page, "READ");
+ rc = iops(inode)->o_brw(READ, iid(inode),inode, page, 0);
+ if (rc == PAGE_SIZE ) {
+ SetPageUptodate(page);
+ UnlockPage(page);
+ }
+ PDEBUG(page, "READ");
+ if ( rc == PAGE_SIZE )
+ rc = 0;
}
- PDEBUG(page, "READ");
- if ( rc == PAGE_SIZE )
- rc = 0;
+ EXIT;
+ return rc;
+}
+
+/*
+ * 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)
{
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;
}