Commit 46d2277c authored by Linus Torvalds's avatar Linus Torvalds

Clean up and make try_to_free_buffers() not race with dirty pages

This is preparatory work in our continuing saga on some hard-to-trigger
file corruption with shared writable mmap() after the dirty page
tracking changes (commit d08b3851 etc)
were merged.
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9bfb1839
...@@ -2834,7 +2834,7 @@ int try_to_free_buffers(struct page *page) ...@@ -2834,7 +2834,7 @@ int try_to_free_buffers(struct page *page)
int ret = 0; int ret = 0;
BUG_ON(!PageLocked(page)); BUG_ON(!PageLocked(page));
if (PageWriteback(page)) if (PageDirty(page) || PageWriteback(page))
return 0; return 0;
if (mapping == NULL) { /* can this still happen? */ if (mapping == NULL) { /* can this still happen? */
...@@ -2845,22 +2845,6 @@ int try_to_free_buffers(struct page *page) ...@@ -2845,22 +2845,6 @@ int try_to_free_buffers(struct page *page)
spin_lock(&mapping->private_lock); spin_lock(&mapping->private_lock);
ret = drop_buffers(page, &buffers_to_free); ret = drop_buffers(page, &buffers_to_free);
spin_unlock(&mapping->private_lock); spin_unlock(&mapping->private_lock);
if (ret) {
/*
* If the filesystem writes its buffers by hand (eg ext3)
* then we can have clean buffers against a dirty page. We
* clean the page here; otherwise later reattachment of buffers
* could encounter a non-uptodate page, which is unresolvable.
* This only applies in the rare case where try_to_free_buffers
* succeeds but the page is not freed.
*
* Also, during truncate, discard_buffer will have marked all
* the page's buffers clean. We discover that here and clean
* the page also.
*/
if (test_clear_page_dirty(page))
task_io_account_cancelled_write(PAGE_CACHE_SIZE);
}
out: out:
if (buffers_to_free) { if (buffers_to_free) {
struct buffer_head *bh = buffers_to_free; struct buffer_head *bh = buffers_to_free;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment