2008-10-21 10:51:53

by Eric Sesterhenn

[permalink] [raw]
Subject: [PATCH 2/2] 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]>


--- linux/fs/bfs/inode.c.1 2008-09-17 16:00:06.000000000 +0200
+++ linux/fs/bfs/inode.c 2008-09-17 16:17:54.000000000 +0200
@@ -390,6 +390,18 @@ static int bfs_fill_super(struct super_b
- 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;