Commit 6ddf3af9 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: clean up condition for writepage sending 



fuse_writepages_fill uses following construction:

if (wpa && ap->num_pages &&
    (A || B || C)) {
        action;
} else if (wpa && D) {
        if (E) {
                the same action;
        }
}

 - ap->num_pages check is always true and can be removed

 - "if" and "else if" calls the same action and can be merged.

Move checking A, B, C, D, E conditions to a helper, add comments.

Original-patch-by: default avatarVasily Averin <vvs@virtuozzo.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent b330966f

fs/fuse/file.c

+35 −18
Original line number Diff line number Diff line
@@ -2015,6 +2015,40 @@ static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa, 
	return false;

}



static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,

				     struct fuse_args_pages *ap,

				     struct fuse_fill_wb_data *data)

{

	WARN_ON(!ap->num_pages);



	/*

	 * Being under writeback is unlikely but possible.  For example direct

	 * read to an mmaped fuse file will set the page dirty twice; once when

	 * the pages are faulted with get_user_pages(), and then after the read

	 * completed.

	 */

	if (fuse_page_is_writeback(data->inode, page->index))

		return true;



	/* Reached max pages */

	if (ap->num_pages == fc->max_pages)

		return true;



	/* Reached max write bytes */

	if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)

		return true;



	/* Discontinuity */

	if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)

		return true;



	/* Need to grow the pages array?  If so, did the expansion fail? */

	if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))

		return true;



	return false;

}



static int fuse_writepages_fill(struct page *page,

		struct writeback_control *wbc, void *_data)

{
@@ -2025,7 +2059,6 @@ static int fuse_writepages_fill(struct page *page, 
	struct fuse_inode *fi = get_fuse_inode(inode);

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct page *tmp_page;

	bool is_writeback;

	int err;



	if (!data->ff) {
@@ -2035,25 +2068,9 @@ static int fuse_writepages_fill(struct page *page, 
			goto out_unlock;

	}



	/*

	 * Being under writeback is unlikely but possible.  For example direct

	 * read to an mmaped fuse file will set the page dirty twice; once when

	 * the pages are faulted with get_user_pages(), and then after the read

	 * completed.

	 */

	is_writeback = fuse_page_is_writeback(inode, page->index);



	if (wpa && ap->num_pages &&

	    (is_writeback || ap->num_pages == fc->max_pages ||

	     (ap->num_pages + 1) * PAGE_SIZE > fc->max_write ||

	     data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)) {

	if (wpa && fuse_writepage_need_send(fc, page, ap, data)) {

		fuse_writepages_send(data);

		data->wpa = NULL;

	} else if (wpa && ap->num_pages == data->max_pages) {

		if (!fuse_pages_realloc(data)) {

			fuse_writepages_send(data);

			data->wpa = NULL;

		}

	}



	err = -ENOMEM;

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