Commit 3d08bcc8 authored May 27, 2011 by Darrick J. Wong Committed by Al Viro May 28, 2011

mm: Wait for writeback when grabbing pages to begin a write



When grabbing a page for a buffered IO write, the mm should wait for writeback
on the page to complete so that the page does not become writable during the IO
operation.  This change is needed to provide page stability during writes for
all filesystems.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent 98702467

mm/filemap.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2327,7 +2327,7 @@ struct page grab_cache_page_write_begin(struct address_space mapping,
		repeat:
		page = find_lock_page(mapping, index);
		if (page)
		return page;
		goto found;

		page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask);
		if (!page)
		@@ -2340,6 +2340,8 @@ repeat:
		goto repeat;
		return NULL;
		}
		found:
		wait_on_page_writeback(page);
		return page;
		}
		EXPORT_SYMBOL(grab_cache_page_write_begin);

Admin message