VFS: fix dio write returning EIO when try_to_release_page fails

[safe/jmp/linux-2.6] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index 42bbc69..876bc59 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -558,14 +558,14 @@ EXPORT_SYMBOL(wait_on_page_bit);
  * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep.
  *
  * The first mb is necessary to safely close the critical section opened by the
- * TestSetPageLocked(), the second mb is necessary to enforce ordering between
- * the clear_bit and the read of the waitqueue (to avoid SMP races with a
- * parallel wait_on_page_locked()).
+ * test_and_set_bit() to lock the page; the second mb is necessary to enforce
+ * ordering between the clear_bit and the read of the waitqueue (to avoid SMP
+ * races with a parallel wait_on_page_locked()).
  */
 void unlock_page(struct page *page)
 {
        smp_mb__before_clear_bit();
-       if (!TestClearPageLocked(page))
+       if (!test_and_clear_bit(PG_locked, &page->flags))
                BUG();
        smp_mb__after_clear_bit(); 
        wake_up_page(page, PG_locked);
@@ -931,7 +931,7 @@ grab_cache_page_nowait(struct address_space *mapping, pgoff_t index)
        struct page *page = find_get_page(mapping, index);
 
        if (page) {
-               if (!TestSetPageLocked(page))
+               if (trylock_page(page))
                        return page;
                page_cache_release(page);
                return NULL;
@@ -1027,7 +1027,7 @@ find_page:
                        if (inode->i_blkbits == PAGE_CACHE_SHIFT ||
                                        !mapping->a_ops->is_partially_uptodate)
                                goto page_not_up_to_date;
-                       if (TestSetPageLocked(page))
+                       if (!trylock_page(page))
                                goto page_not_up_to_date;
                        if (!mapping->a_ops->is_partially_uptodate(page,
                                                                desc, offset))
@@ -1879,7 +1879,7 @@ void iov_iter_advance(struct iov_iter *i, size_t bytes)
                 * The !iov->iov_len check ensures we skip over unlikely
                 * zero-length segments (without overruning the iovec).
                 */
-               while (bytes || unlikely(!iov->iov_len && i->count)) {
+               while (bytes || unlikely(i->count && !iov->iov_len)) {
                        int copy;
 
                        copy = min(bytes, iov->iov_len - base);
@@ -2129,13 +2129,20 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
         * After a write we want buffered reads to be sure to go to disk to get
         * the new data.  We invalidate clean cached page from the region we're
         * about to write.  We do this *before* the write so that we can return
-        * -EIO without clobbering -EIOCBQUEUED from ->direct_IO().
+        * without clobbering -EIOCBQUEUED from ->direct_IO().
         */
        if (mapping->nrpages) {
                written = invalidate_inode_pages2_range(mapping,
                                        pos >> PAGE_CACHE_SHIFT, end);
-               if (written)
+               /*
+                * If a page can not be invalidated, return 0 to fall back
+                * to buffered write.
+                */
+               if (written) {
+                       if (written == -EBUSY)
+                               return 0;
                        goto out;
+               }
        }
 
        written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs);