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md: fix loading of out-of-date bitmap.

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When md is loading a bitmap which it knows is out of date, it fills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.

Cc: stable@kernel.org
Reported-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2009-05-07 12:47:19 +10:00
parent b4348f32da
commit b74fd2826c
1 changed files with 4 additions and 7 deletions
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11
drivers/md/bitmap.c
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@ -986,6 +986,9 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
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* if bitmap is out of date, dirty the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 bitmap *bitmap, sector_t start)
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)