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 <dros@xxxxxxxxxxxxxxx>
---
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 a3e3065..eb1ab6a 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;
--
1.8.5.2 (Apple Git-48)
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