[PATCH] splice: fixup writeout path after ->map changes
Since ->map() no longer locks the page, we need to adjust the handling
of those pages (and stealing) a little. This now passes full regressions
again.
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/fs/splice.c b/fs/splice.c
index 27d6408..22fac87 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -50,7 +50,8 @@
struct page *page = buf->page;
struct address_space *mapping = page_mapping(page);
- WARN_ON(!PageLocked(page));
+ lock_page(page);
+
WARN_ON(!PageUptodate(page));
/*
@@ -65,8 +66,10 @@
if (PagePrivate(page))
try_to_release_page(page, mapping_gfp_mask(mapping));
- if (!remove_mapping(mapping, page))
+ if (!remove_mapping(mapping, page)) {
+ unlock_page(page);
return 1;
+ }
buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU;
return 0;
@@ -507,14 +510,12 @@
if (sd->flags & SPLICE_F_MOVE) {
/*
* If steal succeeds, buf->page is now pruned from the vm
- * side (LRU and page cache) and we can reuse it.
+ * side (LRU and page cache) and we can reuse it. The page
+ * will also be looked on successful return.
*/
if (buf->ops->steal(info, buf))
goto find_page;
- /*
- * this will also set the page locked
- */
page = buf->page;
if (add_to_page_cache(page, mapping, index, gfp_mask))
goto find_page;
@@ -523,15 +524,27 @@
lru_cache_add(page);
} else {
find_page:
- ret = -ENOMEM;
- page = find_or_create_page(mapping, index, gfp_mask);
- if (!page)
- goto out_nomem;
+ page = find_lock_page(mapping, index);
+ if (!page) {
+ ret = -ENOMEM;
+ page = page_cache_alloc_cold(mapping);
+ if (unlikely(!page))
+ goto out_nomem;
+
+ /*
+ * This will also lock the page
+ */
+ ret = add_to_page_cache_lru(page, mapping, index,
+ gfp_mask);
+ if (unlikely(ret))
+ goto out;
+ }
/*
- * If the page is uptodate, it is also locked. If it isn't
- * uptodate, we can mark it uptodate if we are filling the
- * full page. Otherwise we need to read it in first...
+ * We get here with the page locked. If the page is also
+ * uptodate, we don't need to do more. If it isn't, we
+ * may need to bring it in if we are not going to overwrite
+ * the full page.
*/
if (!PageUptodate(page)) {
if (sd->len < PAGE_CACHE_SIZE) {
@@ -553,10 +566,8 @@
ret = -EIO;
goto out;
}
- } else {
- WARN_ON(!PageLocked(page));
+ } else
SetPageUptodate(page);
- }
}
}
@@ -585,10 +596,10 @@
mark_page_accessed(page);
balance_dirty_pages_ratelimited(mapping);
out:
- if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) {
+ if (!(buf->flags & PIPE_BUF_FLAG_STOLEN))
page_cache_release(page);
- unlock_page(page);
- }
+
+ unlock_page(page);
out_nomem:
buf->ops->unmap(info, buf);
return ret;