[PATCH] drop_buffers() oops fix

In rare situations, drop_buffers() can be called for a page which has buffers,
but no ->mapping (it was truncated, but the buffers were left behind because
ext3 was still fiddling with them).

But if there was an I/O error in a buffer_head, drop_buffers() will try to get
at the address_space and will oops.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 3b12cf947aba..665db84a1f9f 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2917,7 +2917,7 @@ drop_buffers(struct page *page, struct buffer_head **buffers_to_free)
 
         bh = head;
         do {
-                if (buffer_write_io_error(bh))
+                if (buffer_write_io_error(bh) && page->mapping)
                         set_bit(AS_EIO, &page->mapping->flags);
                 if (buffer_busy(bh))
                         goto failed;