From: Anand Jain <anand.jain@oracle.com>
To: dsterba@suse.cz, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 10/15] btrfs: drop uuid_mutex in btrfs_free_extra_devids()
Date: Tue, 22 May 2018 17:11:58 +0800 [thread overview]
Message-ID: <2d44cf7d-46e1-194e-06d5-b060859e9a44@oracle.com> (raw)
In-Reply-To: <20180515162647.GT6649@twin.jikos.cz>
On 05/16/2018 12:26 AM, David Sterba wrote:
> On Thu, Apr 12, 2018 at 10:29:33AM +0800, Anand Jain wrote:
>> btrfs_free_extra_devids() frees the orphan fsid::devid but its search is
>> limited to btrfs_fs_devices::devices, so we dont need uuid_mutex.
>
> From that it's not clear why there's no locking at all now:
>
>> @@ -897,7 +897,6 @@ void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step)
>> struct btrfs_device *device, *next;
>> struct btrfs_device *latest_dev = NULL;
>>
>> - mutex_lock(&uuid_mutex);
>
> ie. why is this not replaced by the device_list_lock. Please resend this
> patch and explain in the changelog.
My apologies for the delay.
btrfs_free_extra_devids() needs device_list_mutex, will send a v2 for
this.
Thanks.
>> again:
>> /* This is the initialized path, it is safe to release the devices. */
>> list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
>> @@ -951,8 +950,6 @@ void btrfs_free_extra_devids(struct btrfs_fs_devices *fs_devices, int step)
>> }
>>
>> fs_devices->latest_bdev = latest_dev->bdev;
>> -
>> - mutex_unlock(&uuid_mutex);
>> }
>>
>> static void free_device_rcu(struct rcu_head *head)
> --
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next prev parent reply other threads:[~2018-05-22 9:09 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-12 2:29 [PATCH 0/15] Review uuid_mutex usage Anand Jain
2018-04-12 2:29 ` [PATCH 01/15] btrfs: optimize move uuid_mutex closer to the critical section Anand Jain
2018-04-12 2:29 ` [PATCH 02/15] btrfs: rename struct btrfs_fs_devices::list Anand Jain
2018-04-12 2:29 ` [PATCH 03/15] btrfs: cleanup __btrfs_open_devices() drop head pointer Anand Jain
2018-04-12 2:29 ` [PATCH 04/15] btrfs: rename __btrfs_close_devices to close_fs_devices Anand Jain
2018-04-12 2:29 ` [PATCH 05/15] btrfs: rename __btrfs_open_devices to open_fs_devices Anand Jain
2018-04-12 2:29 ` [PATCH 06/15] btrfs: cleanup find_device() drop list_head pointer Anand Jain
2018-04-12 2:29 ` [PATCH 07/15] btrfs: cleanup btrfs_rm_device() promote fs_devices pointer Anand Jain
2018-04-12 2:29 ` [PATCH 08/15] btrfs: cleanup btrfs_rm_device() use cur_devices Anand Jain
2018-04-12 2:29 ` [PATCH 09/15] btrfs: uuid_mutex in read_chunk_tree, add a comment Anand Jain
2018-04-12 2:29 ` [PATCH 10/15] btrfs: drop uuid_mutex in btrfs_free_extra_devids() Anand Jain
2018-05-15 16:26 ` David Sterba
2018-05-22 9:11 ` Anand Jain [this message]
2018-05-23 2:54 ` [PATCH v3] " Anand Jain
2018-05-25 15:55 ` David Sterba
2018-05-28 10:14 ` [PATCH v4] " Anand Jain
2018-04-12 2:29 ` [PATCH 11/15] btrfs: drop uuid_mutex in btrfs_open_devices() Anand Jain
2018-04-12 2:29 ` [PATCH 12/15] btrfs: drop uuid_mutex in close_fs_devices() Anand Jain
2018-05-15 16:30 ` David Sterba
2018-05-22 9:12 ` Anand Jain
2018-04-12 2:29 ` [PATCH 13/15] btrfs: drop uuid_mutex in btrfs_dev_replace_finishing() Anand Jain
2018-04-12 2:29 ` [PATCH 14/15] btrfs: drop uuid_mutex in btrfs_destroy_dev_replace_tgtdev() Anand Jain
2018-04-12 2:29 ` [PATCH 15/15] btrfs: cleanup btrfs_destroy_dev_replace_tgtdev() localize btrfs_fs_devices Anand Jain
2018-04-16 19:52 ` [PATCH 0/15] Review uuid_mutex usage David Sterba
2018-04-18 9:56 ` [PATCH] btrfs: update uuid_mutex and device_list_mutex comments Anand Jain
2018-04-24 15:48 ` David Sterba
2018-05-16 5:09 ` Anand Jain
2018-04-19 15:22 ` [PATCH 0/15] Review uuid_mutex usage David Sterba
2018-05-15 16:33 ` David Sterba
2018-05-22 9:27 ` Anand Jain
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