From d72ddcbab60a70258d0cd5752db3f53824df78d6 Mon Sep 17 00:00:00 2001 From: Weston Andros Adamson Date: Thu, 15 May 2014 11:56:48 -0400 Subject: [PATCH] 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: Weston Andros Adamson Signed-off-by: Trond Myklebust --- fs/nfs/write.c | 74 +++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 67 insertions(+), 7 deletions(-) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 5d752766139d..17b98952f7bd 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -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; -- 2.34.1