Linux-BTRFS Archive on lore.kernel.org
 help / Atom feed
From: Nikolay Borisov <nborisov@suse.com>
To: Josef Bacik <josef@toxicpanda.com>,
	linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 7/8] btrfs: be more explicit about allowed flush states
Date: Wed, 12 Dec 2018 10:40:49 +0200
Message-ID: <4048c478-67b9-68a8-0c3e-da4cae995db9@suse.com> (raw)
In-Reply-To: <20181203152459.21630-8-josef@toxicpanda.com>



On 3.12.18 г. 17:24 ч., Josef Bacik wrote:
> For FLUSH_LIMIT flushers (think evict, truncate) we can deadlock when
> running delalloc because we may be holding a tree lock.  We can also
> deadlock with delayed refs rsv's that are running via the committing
> mechanism.  The only safe operations for FLUSH_LIMIT is to run the
> delayed operations and to allocate chunks, everything else has the
> potential to deadlock.  Future proof this by explicitly specifying the
> states that FLUSH_LIMIT is allowed to use.  This will keep us from
> introducing bugs later on when adding new flush states.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  fs/btrfs/extent-tree.c | 21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 0e1a499035ac..ab9d915d9289 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -5123,12 +5123,18 @@ void btrfs_init_async_reclaim_work(struct work_struct *work)
>  	INIT_WORK(work, btrfs_async_reclaim_metadata_space);
>  }
>  
> +static const enum btrfs_flush_state priority_flush_states[] = {
> +	FLUSH_DELAYED_ITEMS_NR,
> +	FLUSH_DELAYED_ITEMS,
> +	ALLOC_CHUNK,
> +};
> +
>  static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
>  					    struct btrfs_space_info *space_info,
>  					    struct reserve_ticket *ticket)
>  {
>  	u64 to_reclaim;
> -	int flush_state = FLUSH_DELAYED_ITEMS_NR;
> +	int flush_state = 0;
>  
>  	spin_lock(&space_info->lock);
>  	to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
> @@ -5140,7 +5146,8 @@ static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
>  	spin_unlock(&space_info->lock);
>  
>  	do {
> -		flush_space(fs_info, space_info, to_reclaim, flush_state);
> +		flush_space(fs_info, space_info, to_reclaim,
> +			    priority_flush_states[flush_state]);
>  		flush_state++;
>  		spin_lock(&space_info->lock);
>  		if (ticket->bytes == 0) {
> @@ -5148,15 +5155,7 @@ static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
>  			return;
>  		}
>  		spin_unlock(&space_info->lock);
> -
> -		/*
> -		 * Priority flushers can't wait on delalloc without
> -		 * deadlocking.
> -		 */
> -		if (flush_state == FLUSH_DELALLOC ||
> -		    flush_state == FLUSH_DELALLOC_WAIT)
> -			flush_state = ALLOC_CHUNK;
> -	} while (flush_state < COMMIT_TRANS);
> +	} while (flush_state < ARRAY_SIZE(priority_flush_states));
>  }
>  
>  static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
> 

  parent reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-03 15:24 [PATCH 0/8][V2] Enospc cleanups and fixeS Josef Bacik
2018-12-03 15:24 ` [PATCH 1/8] btrfs: check if free bgs for commit Josef Bacik
2018-12-03 15:24 ` [PATCH 2/8] btrfs: dump block_rsv whe dumping space info Josef Bacik
2018-12-03 15:24 ` [PATCH 3/8] btrfs: don't use global rsv for chunk allocation Josef Bacik
2018-12-11  9:59   ` Nikolay Borisov
2018-12-03 15:24 ` [PATCH 4/8] btrfs: add ALLOC_CHUNK_FORCE to the flushing code Josef Bacik
2018-12-11 10:08   ` Nikolay Borisov
2018-12-11 16:47     ` David Sterba
2018-12-11 16:51       ` Nikolay Borisov
2018-12-11 19:04         ` David Sterba
2018-12-03 15:24 ` [PATCH 5/8] btrfs: don't enospc all tickets on flush failure Josef Bacik
2018-12-11 14:32   ` Nikolay Borisov
2018-12-03 15:24 ` [PATCH 6/8] btrfs: loop in inode_rsv_refill Josef Bacik
2018-12-12 16:01   ` Nikolay Borisov
2019-02-06 18:20     ` David Sterba
2019-01-30 16:41   ` David Sterba
2018-12-03 15:24 ` [PATCH 7/8] btrfs: be more explicit about allowed flush states Josef Bacik
2018-12-11 18:28   ` David Sterba
2018-12-12  8:40   ` Nikolay Borisov [this message]
2018-12-03 15:24 ` [PATCH 8/8] btrfs: reserve extra space during evict() Josef Bacik
2018-12-14  8:20   ` Nikolay Borisov
2018-12-13 14:11 ` [PATCH 0/8][V2] Enospc cleanups and fixeS David Sterba
2018-12-13 14:36   ` Nikolay Borisov
2018-12-13 14:45   ` Josef Bacik
2018-12-13 18:17     ` David Sterba
2018-12-13 18:28       ` Josef Bacik
2018-12-13 18:41         ` David Sterba
2019-02-08 16:08 ` David Sterba
  -- strict thread matches above, loose matches on Subject: below --
2018-11-21 19:03 [PATCH 0/8] Enospc cleanups and fixes Josef Bacik
2018-11-21 19:03 ` [PATCH 7/8] btrfs: be more explicit about allowed flush states Josef Bacik
2018-11-26 12:41   ` Nikolay Borisov
2018-11-26 12:45     ` Nikolay Borisov

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4048c478-67b9-68a8-0c3e-da4cae995db9@suse.com \
    --to=nborisov@suse.com \
    --cc=josef@toxicpanda.com \
    --cc=kernel-team@fb.com \
    --cc=linux-btrfs@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-BTRFS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-btrfs/0 linux-btrfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-btrfs linux-btrfs/ https://lore.kernel.org/linux-btrfs \
		linux-btrfs@vger.kernel.org linux-btrfs@archiver.kernel.org
	public-inbox-index linux-btrfs


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-btrfs


AGPL code for this site: git clone https://public-inbox.org/ public-inbox