2011/5/25 Josef Bacik <josef@xxxxxxxxxx>:
> On 05/25/2011 01:41 PM, matthieu Barthélemy wrote:
>> Finally I successfully remounted my partition. Here is how I've done
>> to recover, in case it can help someone else :
>> I had to clone btrfs-progs-unstable tree.
>> Then checkout branch "tmp" (because I use compression, default
>> btrfs-progs are "too old"
>> Then I compiled btrfs-zero-log with "make btrfs-zero-log"
>> And finally ran "./btrfs-zero-log /dev/sda2"
>>
>> Now I'm copying everything to a new partition, because I don't know if
>> can safely use the damaged one.
>>
>> But wouldn't it be possible to avoid the "Null pointer" kernel crash
>> by checking what we do inside replay_one_buffer, and then
>> automatically clear log, or provide a "clear_log" mount option?
>> Any idea about what could have caused my problem?
>>
>
> Can you do a
>
> gdb btrfs.ko
>
> and then do
>
> list *(add_inode_ref+0x1e7)
Sure, here it is :
# gdb fs/btrfs/btrfs.ko
GNU gdb (GDB) SUSE (7.2-3.3)
[...]
Reading symbols from /home/btrfs-unstable/fs/btrfs/btrfs.ko...done.
(gdb) list *(add_inode_ref+0x1e7)
0x5ce47 is in add_inode_ref (fs/btrfs/tree-log.c:879).
874 * if they are in the log. if so, we allow them to stay
875 * otherwise they must be unlinked as a conflict
876 */
877 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
878 ptr_end = ptr + btrfs_item_size_nr(leaf,
path->slots[0]);
879 while (ptr < ptr_end) {
880 victim_ref = (struct btrfs_inode_ref *)ptr;
881 victim_name_len = btrfs_inode_ref_name_len(leaf,
882
victim_ref);
883 victim_name = kmalloc(victim_name_len,
GFP_NOFS);
> so I can see where it is. It doesn't seem like either of those
> read_extent_buffer's should screw up, either we do the proper checks or
> it should have gone sideways before you got there. Thanks,
Let me know everything I can do to help, I keep my old Btrfs partition
untouched just in case.
I've read in another thread that a new btrfsck will be released "in a
couple of days", this is great news, even if it doesn't handle my
particular problem.
Thanks for your help, and for working so hard on btrfs :-)
>
> Josef
>
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