Re: bcache detach lead to xfs force shutdown

[Coly Li <colyli@suse.de>]

On 2/21/22 5:33 PM, Zhang Zhen wrote:
> Hi coly，
>
> We encounted a bcache detach problem, during the io process，the cache 
> device become missing.
>
> The io error status returned to xfs， and in some case， the xfs do 
> force shutdown.
>
> The dmesg as follows:
> Feb  2 20:59:23  kernel: bcache: bch_count_io_errors() nvme0n1p56: IO 
> error on writing btree.
> Feb  2 20:59:23  kernel: bcache: bch_count_io_errors() nvme0n1p44: IO 
> error on writing btree.
> Feb  2 20:59:23  kernel: bcache: bch_count_io_errors() nvme0n1p44: IO 
> error on writing btree.
> Feb  2 20:59:23  kernel: bcache: bch_count_io_errors() nvme0n1p57: IO 
> error on writing btree.
> Feb  2 20:59:23  kernel: bcache: bch_count_io_errors() nvme0n1p56: IO 
> error on writing btree.
> Feb  2 20:59:23  kernel: bcache: bch_count_io_errors() nvme0n1p57: IO 
> error on writing btree.
> Feb  2 20:59:23  kernel: bcache: bch_count_io_errors() nvme0n1p56: IO 
> error on writing btree.
> Feb  2 20:59:23  kernel: bcache: bch_btree_insert() error -5
> Feb  2 20:59:23  kernel: XFS (bcache43): metadata I/O error in 
> "xfs_buf_iodone_callback_error" at daddr 0x80034658 len 32 error 12
> Feb  2 20:59:23  kernel: bcache: bch_btree_insert() error -5
> Feb  2 20:59:23  kernel: bcache: bch_btree_insert() error -5
> Feb  2 20:59:23  kernel: bcache: bch_btree_insert() error -5
> Feb  2 20:59:23  kernel: bcache: bch_btree_insert() error -5
> Feb  2 20:59:23  kernel: bcache: bch_cache_set_error() bcache: error 
> on 004f8aa7-561a-4ba7-bf7b-292e461d3f18:
> Feb  2 20:59:23  kernel: journal io error
> Feb  2 20:59:23  kernel: bcache: bch_cache_set_error() , disabling 
> caching
> Feb  2 20:59:23  kernel: bcache: bch_btree_insert() error -5
> Feb  2 20:59:23  kernel: bcache: conditional_stop_bcache_device() 
> stop_when_cache_set_failed of bcache43 is "auto" and cache is clean, 
> keep it alive.
> Feb  2 20:59:23  kernel: XFS (bcache43): metadata I/O error in 
> "xlog_iodone" at daddr 0x400123e60 len 64 error 12
> Feb  2 20:59:23  kernel: XFS (bcache43): xfs_do_force_shutdown(0x2) 
> called from line 1298 of file fs/xfs/xfs_log.c. Return address = 
> 00000000c1c8077f
> Feb  2 20:59:23  kernel: XFS (bcache43): Log I/O Error Detected. 
> Shutting down filesystem
> Feb  2 20:59:23  kernel: XFS (bcache43): Please unmount the filesystem 
> and rectify the problem(s)
>
>
> We checked the code, the error status is returned in 
> cached_dev_make_request and closure_bio_submit function.
>
> 1180 static blk_qc_t cached_dev_make_request(struct request_queue *q,
> 1181                     struct bio *bio)
> 1182 {
> 1183     struct search *s;
> 1184     struct bcache_device *d = bio->bi_disk->private_data;
> 1185     struct cached_dev *dc = container_of(d, struct cached_dev, 
> disk);
> 1186     int rw = bio_data_dir(bio);
> 1187
> 1188     if (unlikely((d->c && test_bit(CACHE_SET_IO_DISABLE, 
> &d->c->flags)) ||
> 1189              dc->io_disable)) {
> 1190         bio->bi_status = BLK_STS_IOERR;
> 1191         bio_endio(bio);
> 1192         return BLK_QC_T_NONE;
> 1193     }
>
>  901 static inline void closure_bio_submit(struct cache_set *c,
>  902                       struct bio *bio,
>  903                       struct closure *cl)
>  904 {
>  905     closure_get(cl);
>  906     if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags))) {
>  907         bio->bi_status = BLK_STS_IOERR;
>  908         bio_endio(bio);
>  909         return;
>  910     }
>  911     generic_make_request(bio);
>  912 }
>
> Can the cache set detached and don't return error status to fs?


Hi Zhang,


What is your kernel version and where do you get the kernel?

It seems like an as designed behavior, could you please describe more 
detail about the operation sequence?


Thanks.


Coly Li