path: root/fs
diff options
authorDave Kleikamp <shaggy@linux.vnet.ibm.com>2009-02-06 14:59:26 -0600
committerLinus Torvalds <torvalds@linux-foundation.org>2009-02-06 13:34:22 -0800
commitd4cf109f05ff04c6f5065c3e14165ef01a57dd53 (patch)
tree898a0d6b4d8934ec4939a8572e1b78dbb9689d93 /fs
parent6cec50838ed04a9833fb5549f698d3756bbe7e72 (diff)
vfs: Don't call attach_nobh_buffers() with an empty list
This is a modification of a patch by Bill Pemberton <wfp5p@virginia.edu> nobh_write_end() could call attach_nobh_buffers() with head == NULL. This would result in a trap when attach_nobh_buffers() attempted to access bh->b_this_page. This can be illustrated by running the writev01 testcase from LTP on jfs. This error was introduced by commit 5b41e74a "vfs: fix data leak in nobh_write_end()". That patch did not take into account that if PageMappedToDisk() is true upon entry to nobh_write_begin(), then no buffers will be allocated for the page. In that case, we won't have to worry about a failed write leaving unitialized data in the page. Of course, head != NULL implies !page_has_buffers(page), so no need to test both. Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: Bill Pemberton <wfp5p@virginia.edu> Cc: Dmitri Monakhov <dmonakhov@openvz.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index b58208f1640..665d446b25b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2688,7 +2688,7 @@ int nobh_write_end(struct file *file, struct address_space *mapping,
struct buffer_head *bh;
BUG_ON(fsdata != NULL && page_has_buffers(page));
- if (unlikely(copied < len) && !page_has_buffers(page))
+ if (unlikely(copied < len) && head)
attach_nobh_buffers(page, head);
if (page_has_buffers(page))
return generic_write_end(file, mapping, pos, len,