Diskfs Questions

[sajith]

Hi,

My friends and I are trying to do a JFS translator for the Hurd.
Right at the moment, while simply trying to read the superblock, we're
blocked, and can't comprehend what could be the problem. After the
usual diskfs initialization chores, our create_disk_pager() is doing
this:

struct jfs_superblock *jfs_sb;
struct user_pager_info *upi;
struct port_bucket *pager_bucket;
[..]

diskfs_start_disk_pager (upi, pager_bucket, 1, store->size,
                        &disk_image);
jfs_sb = (struct jfs_superblock *) ((char *)disk_image + SUPER1_OFF);
printf ("jfs_sb->s_magic : %s\n", jfs_sb->s_magic);

With the last printf, translator crashes with this message:

jfs_sb->s_magic ./my_jfs: BUG: unexpected fault on disk image (10,
0x10053000) in [0x1004b000,0x305fb600) eip 0x112d2de err 0xa.

settrans: ./my_jfs: Translator died

And yes, I've done diskfs_console_stdio(). The error message is
apparently from fault-handler() in diskfs/disk-pager.c

Without the printf, the translator appears to startup normally, and I
can attach gdb to it. But when attempted to examine the disk_image,
gdb  stopped. As though disk_image is banned for us.

We haven't implemented all callbacks, could that be the problem?

If anyone have experience with this, please help. I'm new to the Hurd,
so please set your thresholds accordingly.

Thanks, Sajith.