diff --git a/fs/fuse/file.c b/fs/fuse/file.c index e573b0cd2737..57721570c005 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -1674,7 +1674,8 @@ __acquires(fi->lock) } } -static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa) +static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root, + struct fuse_writepage_args *wpa) { pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT; pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1; @@ -1697,11 +1698,17 @@ static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa) else if (idx_to < curr_index) p = &(*p)->rb_left; else - return (void) WARN_ON(true); + return curr; } rb_link_node(&wpa->writepages_entry, parent, p); rb_insert_color(&wpa->writepages_entry, root); + return NULL; +} + +static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa) +{ + WARN_ON(fuse_insert_writeback(root, wpa)); } static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_args *args, @@ -1952,14 +1959,14 @@ static void fuse_writepages_send(struct fuse_fill_wb_data *data) } /* - * First recheck under fi->lock if the offending offset is still under - * writeback. If yes, then iterate auxiliary write requests, to see if there's + * Check under fi->lock if the page is under writeback, and insert it onto the + * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's * one already added for a page at this offset. If there's none, then insert * this new request onto the auxiliary list, otherwise reuse the existing one by - * copying the new page contents over to the old temporary page. + * swapping the new temp page with the old one. */ -static bool fuse_writepage_in_flight(struct fuse_writepage_args *new_wpa, - struct page *page) +static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa, + struct page *page) { struct fuse_inode *fi = get_fuse_inode(new_wpa->inode); struct fuse_writepage_args *tmp; @@ -1967,17 +1974,15 @@ static bool fuse_writepage_in_flight(struct fuse_writepage_args *new_wpa, struct fuse_args_pages *new_ap = &new_wpa->ia.ap; WARN_ON(new_ap->num_pages != 0); + new_ap->num_pages = 1; spin_lock(&fi->lock); - rb_erase(&new_wpa->writepages_entry, &fi->writepages); - old_wpa = fuse_find_writeback(fi, page->index, page->index); + old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa); if (!old_wpa) { - tree_insert(&fi->writepages, new_wpa); spin_unlock(&fi->lock); - return false; + return true; } - new_ap->num_pages = 1; for (tmp = old_wpa->next; tmp; tmp = tmp->next) { pgoff_t curr_index; @@ -2006,7 +2011,7 @@ static bool fuse_writepage_in_flight(struct fuse_writepage_args *new_wpa, fuse_writepage_free(new_wpa); } - return true; + return false; } static int fuse_writepages_fill(struct page *page, @@ -2085,12 +2090,6 @@ static int fuse_writepages_fill(struct page *page, ap->args.end = fuse_writepage_end; ap->num_pages = 0; wpa->inode = inode; - - spin_lock(&fi->lock); - tree_insert(&fi->writepages, wpa); - spin_unlock(&fi->lock); - - data->wpa = wpa; } set_page_writeback(page); @@ -2103,20 +2102,22 @@ static int fuse_writepages_fill(struct page *page, inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP); err = 0; - if (is_writeback && fuse_writepage_in_flight(wpa, page)) { + if (data->wpa) { + /* + * Protected by fi->lock against concurrent access by + * fuse_page_is_writeback(). + */ + spin_lock(&fi->lock); + ap->num_pages++; + spin_unlock(&fi->lock); + } else if (fuse_writepage_add(wpa, page)) { + data->wpa = wpa; + } else { end_page_writeback(page); data->wpa = NULL; goto out_unlock; } - data->orig_pages[ap->num_pages] = page; - - /* - * Protected by fi->lock against concurrent access by - * fuse_page_is_writeback(). - */ - spin_lock(&fi->lock); - ap->num_pages++; - spin_unlock(&fi->lock); + data->orig_pages[ap->num_pages-1] = page; out_unlock: unlock_page(page);