[patch 01/28] md: fix loading of out-of-date bitmap.

Greg KH
2009-05-14T23:02:48Z

[-- Attachment #1: md-fix-loading-of-out-of-date-bitmap.patch --]
[-- Type: text/plain, Size: 1726 bytes --]

2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------

From: NeilBrown <neilb@suse.de>

commit b74fd2826c5acce20e6f691437b2d19372bc2057 upstream.

When md is loading a bitmap which it knows is out of date, it fills
each page with 1s and writes it back out again. However the
write_page call makes used of bitmap->file_pages and
bitmap->last_page_size which haven't been set correctly yet. So this
can sometimes fail.

Move the setting of file_pages and last_page_size to before the call
to write_page.

This bug can cause the assembly on an array to fail, thus making the
data inaccessible. Hence I think it is a suitable candidate for
-stable.

Reported-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/md/bitmap.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -986,6 +986,9 @@ static int bitmap_init_from_disk(struct
oldindex = index;
oldpage = page;

+ bitmap->filemap[bitmap->file_pages++] = page;
+ bitmap->last_page_size = count;
+
if (outofdate) {
/*
* if bitmap is out of date, dirty the
@@ -998,15 +1001,9 @@ static int bitmap_init_from_disk(struct
write_page(bitmap, page, 1);

ret = -EIO;
- if (bitmap->flags & BITMAP_WRITE_ERROR) {
- /* release, page not in filemap yet */
- put_page(page);
+ if (bitmap->flags & BITMAP_WRITE_ERROR)
goto err;
- }
}
-
- bitmap->filemap[bitmap->file_pages++] = page;
- bitmap->last_page_size = count;
}
paddr = kmap_atomic(page, KM_USER0);
if (bitmap->flags & BITMAP_HOSTENDIAN)