Fix a buglet in invalidate_list_pages2(): there is a small window in
which writeback could start against the page before this function locks
it.
The patch closes the race by performing the PageWriteback test inside
PageLocked.
Testing PageWriteback inside PageLocked is "definitive" - when a page
is locked, writeback cannot start against it.
filemap.c | 16 +++++++++-------
1 files changed, 9 insertions(+), 7 deletions(-)
--- 2.5.24/mm/filemap.c~invalidate-race Thu Jul 4 16:17:32 2002
+++ 2.5.24-akpm/mm/filemap.c Thu Jul 4 16:17:32 2002
@@ -367,16 +367,18 @@ static int invalidate_list_pages2(struct
while (curr != head) {
page = list_entry(curr, struct page, list);
- if (PageWriteback(page)) {
- write_unlock(&mapping->page_lock);
- wait_on_page_writeback(page);
- unlocked = 1;
- write_lock(&mapping->page_lock);
- goto restart;
- }
if (!TestSetPageLocked(page)) {
int __unlocked;
+ if (PageWriteback(page)) {
+ write_unlock(&mapping->page_lock);
+ wait_on_page_writeback(page);
+ unlocked = 1;
+ write_lock(&mapping->page_lock);
+ unlock_page(page);
+ goto restart;
+ }
+
__unlocked = invalidate_this_page2(mapping, page, curr, head);
unlock_page(page);
unlocked |= __unlocked;
-
-
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This archive was generated by hypermail 2b29 : Sun Jul 07 2002 - 22:00:14 EST