bfs: check that filesystem fits on the blockdevice

Since all sanity checks rely on the validity of s_start which gets only checked to be smaller than s_end, we should also check if s_end is sane. Now we also try to retrieve the last block of the filesystem, which is computed by s_end. If this fails, something is bogus. Signed-off-by: Eric Sesterhenn <[email protected]> Acked-by: Tigran Aivazian <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
iegor · Jan 6, 2009 · 50682bb · 50682bb
1 parent e1f89ec
commit 50682bb
Showing 1 changed file with 12 additions and 0 deletions.
diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
@@ -390,6 +390,18 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
 			- le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
 	info->si_freei = 0;
 	info->si_lf_eblk = 0;
+
+	/* can we read the last block? */
+	bh = sb_bread(s, info->si_blocks - 1);
+	if (!bh) {
+		printf("Last block not available: %lu\n", info->si_blocks - 1);
+		iput(inode);
+		ret = -EIO;
+		kfree(info->si_imap);
+		goto out;
+	}
+	brelse(bh);
+
 	bh = NULL;
 	for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
 		struct bfs_inode *di;