[PATCH] md: avoid reading past the end of a bitmap file

[pandora-kernel.git] / drivers / md / bitmap.c

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 5432d07..1110816 100644 (file)
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -479,9 +479,12 @@ static int bitmap_read_sb(struct bitmap *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 bitmap *bitmap, sector_t start)
                        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) {