return 0;
write_lock_irq(&mapping->tree_lock);
- if (PageDirty(page)) {
- write_unlock_irq(&mapping->tree_lock);
- return 0;
- }
+ if (PageDirty(page))
+ goto failed;
+ if (page_count(page) != 2) /* caller's ref + pagecache ref */
+ goto failed;
BUG_ON(PagePrivate(page));
__remove_from_page_cache(page);
ClearPageUptodate(page);
page_cache_release(page); /* pagecache ref */
return 1;
+failed:
+ write_unlock_irq(&mapping->tree_lock);
+ return 0;
}
/**
* @mapping: mapping to truncate
* @lstart: offset from which to truncate
*
- * Called under (and serialised by) inode->i_sem.
+ * Called under (and serialised by) inode->i_mutex.
*/
void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
{
pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
+ pgoff_t index;
+ int lock_failed;
- if (TestSetPageLocked(page)) {
- next++;
- continue;
- }
- if (page->index > next)
- next = page->index;
+ lock_failed = TestSetPageLocked(page);
+
+ /*
+ * We really shouldn't be looking at the ->index of an
+ * unlocked page. But we're not allowed to lock these
+ * pages. So we rely upon nobody altering the ->index
+ * of this (pinned-by-us) page.
+ */
+ index = page->index;
+ if (index > next)
+ next = index;
next++;
+ if (lock_failed)
+ continue;
+
if (PageDirty(page) || PageWriteback(page))
goto unlock;
if (page_mapped(page))
break;
}
pagevec_release(&pvec);
- cond_resched();
}
return ret;
}