In most cases we check the size of the bitmap file before
reading data from it. However when reading the superblock,
we always read the first PAGE_SIZE bytes, which might not
always be appropriate. So limit that read to the size of the
file if appropriate.
Also, we get the count of available bytes wrong in one place,
so that too can read past the end of the file.
Cc: "yang yin" <[EMAIL PROTECTED]>
Signed-off-by: Neil Brown <[EMAIL PROTECTED]>
### Diffstat output
./drivers/md/bitmap.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff .prev/drivers/md/bitmap.c ./drivers/md/bitmap.c
--- .prev/drivers/md/bitmap.c 2007-01-23 11:13:43.000000000 +1100
+++ ./drivers/md/bitmap.c 2007-01-23 11:24:09.000000000 +1100
@@ -479,9 +479,12 @@ static int bitmap_read_sb(struct bitmap
int err = -EINVAL;
/* page 0 is the superblock, read it... */
- if (bitmap->file)
- bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
- else {
+ if (bitmap->file) {
+ loff_t isize = i_size_read(bitmap->file->f_mapping->host);
+ int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
+
+ bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
+ } else {
bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset,
0);
}
if (IS_ERR(bitmap->sb_page)) {
@@ -877,7 +880,8 @@ static int bitmap_init_from_disk(struct
int count;
/* unmap the old page, we're done with it */
if (index == num_pages-1)
- count = bytes - index * PAGE_SIZE;
+ count = bytes + sizeof(bitmap_super_t)
+ - index * PAGE_SIZE;
else
count = PAGE_SIZE;
if (index == 0) {
-
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