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From: Anand Jain <anand.jain@oracle.com>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v3.1 1/7] btrfs: Introduce a function to check if all chunks a OK for degraded rw mount
Date: Mon, 13 Mar 2017 15:29:06 +0800	[thread overview]
Message-ID: <f01fd9f3-85fe-c390-5358-be8c5d67ebc6@oracle.com> (raw)
In-Reply-To: <20170309013442.19957-2-quwenruo@cn.fujitsu.com>



On 03/09/2017 09:34 AM, Qu Wenruo wrote:
> Introduce a new function, btrfs_check_rw_degradable(), to check if all
> chunks in btrfs is OK for degraded rw mount.
>
> It provides the new basis for accurate btrfs mount/remount and even
> runtime degraded mount check other than old one-size-fit-all method.
>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> Tested-by: Austin S. Hemmelgarn <ahferroin7@gmail.com>
> Tested-by: Adam Borowski <kilobyte@angband.pl>
> Tested-by: Dmitrii Tcvetkov <demfloro@demfloro.ru>
> ---
>  fs/btrfs/volumes.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/btrfs/volumes.h |  1 +
>  2 files changed, 56 insertions(+)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 73d56eef5e60..83613955e3c2 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -6765,6 +6765,61 @@ int btrfs_read_sys_array(struct btrfs_fs_info *fs_info)
>  	return -EIO;
>  }
>
> +/*
> + * Check if all chunks in the fs is OK for read-write degraded mount
> + *
> + * Return true if the fs is OK to be mounted degraded read-write
> + * Return false if the fs is not OK to be mounted degraded
> + */
> +bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info)
> +{
> +	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
> +	struct extent_map *em;
> +	u64 next_start = 0;
> +	bool ret = true;
> +
> +	read_lock(&map_tree->map_tree.lock);
> +	em = lookup_extent_mapping(&map_tree->map_tree, 0, (u64)-1);
> +	read_unlock(&map_tree->map_tree.lock);
> +	/* No chunk at all? Return false anyway */
> +	if (!em) {
> +		ret = false;
> +		goto out;
> +	}
> +	while (em) {
> +		struct map_lookup *map;
> +		int missing = 0;
> +		int max_tolerated;
> +		int i;
> +
> +		map = (struct map_lookup *) em->bdev;


    any idea why not   map = em->map_lookup;  here?

Thanks, Anand


> +		max_tolerated =
> +			btrfs_get_num_tolerated_disk_barrier_failures(
> +					map->type);
> +		for (i = 0; i < map->num_stripes; i++) {
> +			if (map->stripes[i].dev->missing)
> +				missing++;
> +		}
> +		if (missing > max_tolerated) {
> +			ret = false;
> +			btrfs_warn(fs_info,
> +	"chunk %llu missing %d devices, max tolerance is %d for writeble mount",
> +				   em->start, missing, max_tolerated);
> +			free_extent_map(em);
> +			goto out;
> +		}
> +		next_start = extent_map_end(em);
> +		free_extent_map(em);
> +
> +		read_lock(&map_tree->map_tree.lock);
> +		em = lookup_extent_mapping(&map_tree->map_tree, next_start,
> +					   (u64)(-1) - next_start);
> +		read_unlock(&map_tree->map_tree.lock);
> +	}
> +out:
> +	return ret;
> +}
> +
>  int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info)
>  {
>  	struct btrfs_root *root = fs_info->chunk_root;
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index 59be81206dd7..db1b5ef479cf 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -538,4 +538,5 @@ struct list_head *btrfs_get_fs_uuids(void);
>  void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info);
>  void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info);
>
> +bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info);
>  #endif
>

  reply	other threads:[~2017-03-13  7:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-09  1:34 [PATCH v3.1 0/7] Chunk level degradable check Qu Wenruo
2017-03-09  1:34 ` [PATCH v3.1 1/7] btrfs: Introduce a function to check if all chunks a OK for degraded rw mount Qu Wenruo
2017-03-13  7:29   ` Anand Jain [this message]
2017-03-13  7:25     ` Qu Wenruo
2017-05-01 10:21       ` Dmitrii Tcvetkov
2017-05-02  0:20         ` Qu Wenruo
2017-05-02  2:28           ` Anand Jain
2017-03-09  1:34 ` [PATCH v3.1 2/7] btrfs: Do chunk level rw degrade check at mount time Qu Wenruo
2017-03-09  1:34 ` [PATCH v3.1 3/7] btrfs: Do chunk level degradation check for remount Qu Wenruo
2017-03-09  1:34 ` [PATCH v3.1 4/7] btrfs: Introduce extra_rw_degrade_errors parameter for btrfs_check_rw_degradable Qu Wenruo
2017-03-09  1:34 ` [PATCH v3.1 5/7] btrfs: Allow barrier_all_devices to do chunk level device check Qu Wenruo
2017-03-13  8:00   ` Anand Jain
2017-03-09  1:34 ` [PATCH v3.1 6/7] btrfs: Cleanup num_tolerated_disk_barrier_failures Qu Wenruo
2017-03-09  1:34 ` [PATCH v3.1 7/7] btrfs: Enhance missing device kernel message Qu Wenruo
2017-06-26 18:59 ` [PATCH v3.1 0/7] Chunk level degradable check David Sterba
2017-06-27  1:05   ` Qu Wenruo
2017-06-27  1:59     ` Anand Jain
2017-06-27  2:49       ` Qu Wenruo
2017-06-27 11:20         ` Austin S. Hemmelgarn
2017-06-27 12:20           ` David Sterba

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