On 09/21/2012 11:46 AM, Marc MERLIN wrote:

On Thu, Sep 20, 2012 at 10:17:47AM -0700, Marc MERLIN wrote:

quoted

I had a btrfs built on top of 5 drives (dmcrypt devices).

The drive then died while I was writing to the filesystem and my system
crashed and rebooted:

[384555.534020] sd 10:0:0:0: rejecting I/O to offline device                    
[384555.535057] sd 10:0:0:0: rejecting I/O to offline device                    
[384556.666885] ------------[ cut here ]------------                            
[384556.667909] sd 10:0:0:0: [sdj] Synchronizing SCSI cache                     
[384556.677509] kernel BUG at fs/btrfs/ctree.c:3451!                            
[384556.682551] invalid opcode: 0000 [#1] PREEMPT SMP                           
[384556.687878] CPU 2                                                           

 
Oh my, now I'm trying again with a new drive, and a big cp from an
existing array to a new one dies with:
[32042.079411] ------------[ cut here ]------------                             
[32042.085799] kernel BUG at fs/btrfs/extent_io.c:1884!                         
[32042.092528] invalid opcode: 0000 [#1] PREEMPT SMP                            
[32042.099227] CPU 1                                                            
[32042.101095] Modules linked in:[32042.105950]  raid456 async_raid6_recov async
_pq raid6_pq async_xor xor async_memcpy async_tx ppdev lp tun autofs4 kl5kusb105
 ftdi_sio keyspan nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc rc_ati_x10 s
nd_timer i915 usbserial snd drm_kms_helper eeepc_wmi drm ati_remote asus_wmi rc_
core sparse_keymap    

    int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start,
			    u64 length, u64 logical, struct page *page,
			    int mirror_num)
    {
	    struct bio *bio;
	    struct btrfs_device *dev;
	    DECLARE_COMPLETION_ONSTACK(compl);
	    u64 map_length = 0;
	    u64 sector;
	    struct btrfs_bio *bbio = NULL;
	    int ret;

	    BUG_ON(!mirror_num); <<<<<

This is more of a problem since I can't backup my filesystem (source is
ext4 and destination is btrfs).

Any suggestion on what went wrong here?

Could you please show us the complete stack info?

thanks,
liubo

Thanks,
Marc