Commit d72ddcba authored by Weston Andros Adamson's avatar Weston Andros Adamson Committed by Trond Myklebust
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nfs: page group support in nfs_mark_uptodate 



Change how nfs_mark_uptodate checks to see if writes cover a whole page.

This patch should have no effect yet since all page groups currently
have one request, but will come into play when pg_test functions are
modified to split pages into sub-page regions.

Signed-off-by: default avatarWeston Andros Adamson <dros@primarydata.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 20633f04

fs/nfs/write.c

+67 −7
Original line number Diff line number Diff line
@@ -154,18 +154,78 @@ static void nfs_set_pageerror(struct page *page) 
	nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));

}



/*

 * nfs_page_group_search_locked

 * @head - head request of page group

 * @page_offset - offset into page

 *

 * Search page group with head @head to find a request that contains the

 * page offset @page_offset.

 *

 * Returns a pointer to the first matching nfs request, or NULL if no

 * match is found.

 *

 * Must be called with the page group lock held

 */

static struct nfs_page *

nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)

{

	struct nfs_page *req;



	WARN_ON_ONCE(head != head->wb_head);

	WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_head->wb_flags));



	req = head;

	do {

		if (page_offset >= req->wb_pgbase &&

		    page_offset < (req->wb_pgbase + req->wb_bytes))

			return req;



		req = req->wb_this_page;

	} while (req != head);



	return NULL;

}



/*

 * nfs_page_group_covers_page

 * @head - head request of page group

 *

 * Return true if the page group with head @head covers the whole page,

 * returns false otherwise

 */

static bool nfs_page_group_covers_page(struct nfs_page *req)

{

	struct nfs_page *tmp;

	unsigned int pos = 0;

	unsigned int len = nfs_page_length(req->wb_page);



	nfs_page_group_lock(req);



	do {

		tmp = nfs_page_group_search_locked(req->wb_head, pos);

		if (tmp) {

			/* no way this should happen */

			WARN_ON_ONCE(tmp->wb_pgbase != pos);

			pos += tmp->wb_bytes - (pos - tmp->wb_pgbase);

		}

	} while (tmp && pos < len);



	nfs_page_group_unlock(req);

	WARN_ON_ONCE(pos > len);

	return pos == len;

}



/* We can set the PG_uptodate flag if we see that a write request

 * covers the full page.

 */

static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)

static void nfs_mark_uptodate(struct nfs_page *req)

{

	if (PageUptodate(page))

		return;

	if (base != 0)

	if (PageUptodate(req->wb_page))

		return;

	if (count != nfs_page_length(page))

	if (!nfs_page_group_covers_page(req))

		return;

	SetPageUptodate(page);

	SetPageUptodate(req->wb_page);

}



static int wb_priority(struct writeback_control *wbc)
@@ -796,7 +856,7 @@ static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page, 
		return PTR_ERR(req);

	/* Update file length */

	nfs_grow_file(page, offset, count);

	nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);

	nfs_mark_uptodate(req);

	nfs_mark_request_dirty(req);

	nfs_unlock_and_release_request(req);

	return 0;

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