From: Anand Jain <anand.jain@oracle.com>
To: Naohiro Aota <naohiro.aota@wdc.com>,
linux-btrfs@vger.kernel.org, dsterba@suse.com
Cc: hare@suse.com, linux-fsdevel@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>,
Josef Bacik <josef@toxicpanda.com>
Subject: Re: [PATCH v14 05/42] btrfs: release path before calling into btrfs_load_block_group_zone_info
Date: Sun, 31 Jan 2021 07:21:38 +0800 [thread overview]
Message-ID: <d7e18cf7-ad33-7052-15c7-3dff3fa8f635@oracle.com> (raw)
In-Reply-To: <d931b0c588dda740d140a1d8e87eb5b138869fc5.1611627788.git.naohiro.aota@wdc.com>
On 1/26/2021 10:24 AM, Naohiro Aota wrote:
> From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> Since we have no write pointer in conventional zones, we cannot determine
> the allocation offset from it. Instead, we set the allocation offset after
> the highest addressed extent. This is done by reading the extent tree in
> btrfs_load_block_group_zone_info().
>
> However, this function is called from btrfs_read_block_groups(), so the
> read lock for the tree node can recursively taken.
>
> To avoid this unsafe locking scenario, release the path before reading the
> extent tree to get the allocation offset.
>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Looks good to me.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Thanks.
> ---
> fs/btrfs/block-group.c | 39 ++++++++++++++++++---------------------
> 1 file changed, 18 insertions(+), 21 deletions(-)
>
> diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
> index 763a3671b7af..bdd20af69dde 100644
> --- a/fs/btrfs/block-group.c
> +++ b/fs/btrfs/block-group.c
> @@ -1805,24 +1805,8 @@ static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
> return ret;
> }
>
> -static void read_block_group_item(struct btrfs_block_group *cache,
> - struct btrfs_path *path,
> - const struct btrfs_key *key)
> -{
> - struct extent_buffer *leaf = path->nodes[0];
> - struct btrfs_block_group_item bgi;
> - int slot = path->slots[0];
> -
> - cache->length = key->offset;
> -
> - read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
> - sizeof(bgi));
> - cache->used = btrfs_stack_block_group_used(&bgi);
> - cache->flags = btrfs_stack_block_group_flags(&bgi);
> -}
> -
> static int read_one_block_group(struct btrfs_fs_info *info,
> - struct btrfs_path *path,
> + struct btrfs_block_group_item *bgi,
> const struct btrfs_key *key,
> int need_clear)
> {
> @@ -1837,7 +1821,9 @@ static int read_one_block_group(struct btrfs_fs_info *info,
> if (!cache)
> return -ENOMEM;
>
> - read_block_group_item(cache, path, key);
> + cache->length = key->offset;
> + cache->used = btrfs_stack_block_group_used(bgi);
> + cache->flags = btrfs_stack_block_group_flags(bgi);
>
> set_free_space_tree_thresholds(cache);
>
> @@ -1996,19 +1982,30 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
> need_clear = 1;
>
> while (1) {
> + struct btrfs_block_group_item bgi;
> + struct extent_buffer *leaf;
> + int slot;
> +
> ret = find_first_block_group(info, path, &key);
> if (ret > 0)
> break;
> if (ret != 0)
> goto error;
>
> - btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
> - ret = read_one_block_group(info, path, &key, need_clear);
> + leaf = path->nodes[0];
> + slot = path->slots[0];
> +
> + read_extent_buffer(leaf, &bgi,
> + btrfs_item_ptr_offset(leaf, slot),
> + sizeof(bgi));
> +
> + btrfs_item_key_to_cpu(leaf, &key, slot);
> + btrfs_release_path(path);
> + ret = read_one_block_group(info, &bgi, &key, need_clear);
> if (ret < 0)
> goto error;
> key.objectid += key.offset;
> key.offset = 0;
> - btrfs_release_path(path);
> }
> btrfs_release_path(path);
>
>
next prev parent reply other threads:[~2021-01-30 23:22 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 2:24 [PATCH v14 00/42] btrfs: zoned block device support Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 01/42] block: add bio_add_zone_append_page Naohiro Aota
2021-01-26 16:08 ` Jens Axboe
2021-01-26 2:24 ` [PATCH v14 02/42] iomap: support REQ_OP_ZONE_APPEND Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 03/42] btrfs: defer loading zone info after opening trees Naohiro Aota
2021-01-30 22:09 ` Anand Jain
2021-01-26 2:24 ` [PATCH v14 04/42] btrfs: use regular SB location on emulated zoned mode Naohiro Aota
2021-01-30 22:28 ` Anand Jain
2021-01-26 2:24 ` [PATCH v14 05/42] btrfs: release path before calling into btrfs_load_block_group_zone_info Naohiro Aota
2021-01-30 23:21 ` Anand Jain [this message]
2021-01-26 2:24 ` [PATCH v14 06/42] btrfs: do not load fs_info->zoned from incompat flag Naohiro Aota
2021-01-30 23:40 ` Anand Jain
2021-01-26 2:24 ` [PATCH v14 07/42] btrfs: disallow fitrim in ZONED mode Naohiro Aota
2021-01-30 23:44 ` Anand Jain
2021-01-26 2:24 ` [PATCH v14 08/42] btrfs: allow zoned mode on non-zoned block devices Naohiro Aota
2021-01-31 1:17 ` Anand Jain
2021-02-01 11:06 ` Johannes Thumshirn
2021-02-02 1:49 ` Anand Jain
2021-01-26 2:24 ` [PATCH v14 09/42] btrfs: implement zoned chunk allocator Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 10/42] btrfs: verify device extent is aligned to zone Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 11/42] btrfs: load zone's allocation offset Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 12/42] btrfs: calculate allocation offset for conventional zones Naohiro Aota
2021-01-27 18:03 ` Josef Bacik
2021-02-03 5:19 ` Anand Jain
2021-02-03 6:10 ` Damien Le Moal
2021-02-03 6:56 ` Anand Jain
2021-02-03 7:10 ` Damien Le Moal
2021-01-26 2:24 ` [PATCH v14 13/42] btrfs: track unusable bytes for zones Naohiro Aota
2021-01-27 18:06 ` Josef Bacik
2021-01-26 2:24 ` [PATCH v14 14/42] btrfs: do sequential extent allocation in ZONED mode Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 15/42] btrfs: redirty released extent buffers " Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 16/42] btrfs: advance allocation pointer after tree log node Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 17/42] btrfs: enable to mount ZONED incompat flag Naohiro Aota
2021-01-31 12:21 ` Anand Jain
2021-01-26 2:24 ` [PATCH v14 18/42] btrfs: reset zones of unused block groups Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 19/42] btrfs: extract page adding function Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 20/42] btrfs: use bio_add_zone_append_page for zoned btrfs Naohiro Aota
2021-01-26 2:24 ` [PATCH v14 21/42] btrfs: handle REQ_OP_ZONE_APPEND as writing Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 22/42] btrfs: split ordered extent when bio is sent Naohiro Aota
2021-01-27 19:00 ` Josef Bacik
2021-01-26 2:25 ` [PATCH v14 23/42] btrfs: check if bio spans across an ordered extent Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 24/42] btrfs: extend btrfs_rmap_block for specifying a device Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 25/42] btrfs: cache if block-group is on a sequential zone Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 26/42] btrfs: save irq flags when looking up an ordered extent Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 27/42] btrfs: use ZONE_APPEND write for ZONED btrfs Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 28/42] btrfs: enable zone append writing for direct IO Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 29/42] btrfs: introduce dedicated data write path for ZONED mode Naohiro Aota
2021-02-02 15:00 ` David Sterba
2021-02-04 8:25 ` Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 30/42] btrfs: serialize meta IOs on " Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 31/42] btrfs: wait existing extents before truncating Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 32/42] btrfs: avoid async metadata checksum on ZONED mode Naohiro Aota
2021-02-02 14:54 ` David Sterba
2021-02-02 16:50 ` Johannes Thumshirn
2021-02-02 19:28 ` David Sterba
2021-01-26 2:25 ` [PATCH v14 33/42] btrfs: mark block groups to copy for device-replace Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 34/42] btrfs: implement cloning for ZONED device-replace Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 35/42] btrfs: implement copying " Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 36/42] btrfs: support dev-replace in ZONED mode Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 37/42] btrfs: enable relocation " Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 38/42] btrfs: relocate block group to repair IO failure in ZONED Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 39/42] btrfs: split alloc_log_tree() Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 40/42] btrfs: extend zoned allocator to use dedicated tree-log block group Naohiro Aota
2021-01-26 2:25 ` [PATCH v14 41/42] btrfs: serialize log transaction on ZONED mode Naohiro Aota
2021-01-27 19:01 ` Josef Bacik
2021-02-01 15:48 ` Filipe Manana
2021-01-26 2:25 ` [PATCH v14 42/42] btrfs: reorder log node allocation Naohiro Aota
2021-02-01 15:48 ` Filipe Manana
2021-02-01 15:54 ` Johannes Thumshirn
2021-01-29 7:56 ` [PATCH v14 00/42] btrfs: zoned block device support Johannes Thumshirn
2021-01-29 20:44 ` David Sterba
2021-01-30 11:30 ` Johannes Thumshirn
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