ACK: [D/E][PATCH 1/1] Revert "bcache: set CACHE_SET_IO_DISABLE in bch_cached_dev_error()"

[Connor Kuehl]

On 7/7/19 7:51 PM, Mauricio Faria de Oliveira wrote:
> From: Coly Li <colyli at suse.de>
> 
> BugLink: https://bugs.launchpad.net/bugs/1829563
> 
> This reverts commit 6147305c73e4511ca1a975b766b97a779d442567.
> 
> Although this patch helps the failed bcache device to stop faster when
> too many I/O errors detected on corresponding cached device, setting
> CACHE_SET_IO_DISABLE bit to cache set c->flags was not a good idea. This
> operation will disable all I/Os on cache set, which means other attached
> bcache devices won't work neither.
> 
> Without this patch, the failed bcache device can also be stopped
> eventually if internal I/O accomplished (e.g. writeback). Therefore here
> I revert it.
> 
> Fixes: 6147305c73e4 ("bcache: set CACHE_SET_IO_DISABLE in bch_cached_dev_error()")
> Reported-by: Yong Li <mr.liyong at qq.com>
> Signed-off-by: Coly Li <colyli at suse.de>
> Cc: stable at vger.kernel.org
> Signed-off-by: Jens Axboe <axboe at kernel.dk>
> (cherry picked from commit 695277f16b3a102fcc22c97fdf2de77c7b19f0b3 linux-next)
> Signed-off-by: Mauricio Faria de Oliveira <mfo at canonical.com>

Acked-by: Connor Kuehl <connor.kuehl at canonical.com>

> ---
>  drivers/md/bcache/super.c | 17 -----------------
>  1 file changed, 17 deletions(-)
> 
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 169a959593e4..97db3daf3a77 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1436,8 +1436,6 @@ int bch_flash_dev_create(struct cache_set *c, uint64_t size)
>  
>  bool bch_cached_dev_error(struct cached_dev *dc)
>  {
> -	struct cache_set *c;
> -
>  	if (!dc || test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
>  		return false;
>  
> @@ -1448,21 +1446,6 @@ bool bch_cached_dev_error(struct cached_dev *dc)
>  	pr_err("stop %s: too many IO errors on backing device %s\n",
>  		dc->disk.disk->disk_name, dc->backing_dev_name);
>  
> -	/*
> -	 * If the cached device is still attached to a cache set,
> -	 * even dc->io_disable is true and no more I/O requests
> -	 * accepted, cache device internal I/O (writeback scan or
> -	 * garbage collection) may still prevent bcache device from
> -	 * being stopped. So here CACHE_SET_IO_DISABLE should be
> -	 * set to c->flags too, to make the internal I/O to cache
> -	 * device rejected and stopped immediately.
> -	 * If c is NULL, that means the bcache device is not attached
> -	 * to any cache set, then no CACHE_SET_IO_DISABLE bit to set.
> -	 */
> -	c = dc->disk.c;
> -	if (c && test_and_set_bit(CACHE_SET_IO_DISABLE, &c->flags))
> -		pr_info("CACHE_SET_IO_DISABLE already set");
> -
>  	bcache_device_stop(&dc->disk);
>  	return true;
>  }
>