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[3/4] btrfs: fix rw_devices miss match after seed replace

Message ID 1407750176-15853-3-git-send-email-anand.jain@oracle.com (mailing list archive)
State Superseded
Headers show

Commit Message

Anand Jain Aug. 11, 2014, 9:42 a.m. UTC
reproducer:
    reproducer:
    mount /dev/sdb /btrfs
    btrfs dev add /dev/sdc /btrfs
    btrfs rep start -B /dev/sdb /dev/sdd /btrfs
    umount /btrfs

WARNING: CPU: 0 PID: 3882 at fs/btrfs/volumes.c:892 __btrfs_close_devices+0x1c8/0x200 [btrfs]()

which is

        WARN_ON(fs_devices->rw_devices);

   The problem here is that we did not add one to the rw_devices when
   we replace the seed device with a writable device.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 fs/btrfs/dev-replace.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Miao Xie Aug. 12, 2014, 7:29 a.m. UTC | #1
On Mon, 11 Aug 2014 17:42:55 +0800, Anand Jain wrote:
> reproducer:
>     reproducer:
>     mount /dev/sdb /btrfs
>     btrfs dev add /dev/sdc /btrfs
>     btrfs rep start -B /dev/sdb /dev/sdd /btrfs
>     umount /btrfs
> 
> WARNING: CPU: 0 PID: 3882 at fs/btrfs/volumes.c:892 __btrfs_close_devices+0x1c8/0x200 [btrfs]()
> 
> which is
> 
>         WARN_ON(fs_devices->rw_devices);
> 
>    The problem here is that we did not add one to the rw_devices when
>    we replace the seed device with a writable device.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
>  fs/btrfs/dev-replace.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index eea26e1..fb0a7fa 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -562,6 +562,8 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
>  	if (fs_info->fs_devices->latest_bdev == src_device->bdev)
>  		fs_info->fs_devices->latest_bdev = tgt_device->bdev;
>  	list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
> +	if (src_device->fs_devices->seeding)
> +		fs_info->fs_devices->rw_devices++;

As I said in the previous version of this patch, we might increase ->rw_devices twice if
the source device is a missing device in the seed filesystem. Once is here, the other is
in btrfs_rm_dev_replace_srcdev().

Thanks
Miao

>  
>  	/* replace the sysfs entry */
>  	btrfs_kobj_rm_device(fs_info, src_device);
> 

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Anand Jain Aug. 12, 2014, 8 a.m. UTC | #2
On 12/08/2014 15:29, Miao Xie wrote:
> On Mon, 11 Aug 2014 17:42:55 +0800, Anand Jain wrote:
>> reproducer:
>>      reproducer:
>>      mount /dev/sdb /btrfs
>>      btrfs dev add /dev/sdc /btrfs
>>      btrfs rep start -B /dev/sdb /dev/sdd /btrfs
>>      umount /btrfs
>>
>> WARNING: CPU: 0 PID: 3882 at fs/btrfs/volumes.c:892 __btrfs_close_devices+0x1c8/0x200 [btrfs]()
>>
>> which is
>>
>>          WARN_ON(fs_devices->rw_devices);
>>
>>     The problem here is that we did not add one to the rw_devices when
>>     we replace the seed device with a writable device.
>>
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>> ---
>>   fs/btrfs/dev-replace.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
>> index eea26e1..fb0a7fa 100644
>> --- a/fs/btrfs/dev-replace.c
>> +++ b/fs/btrfs/dev-replace.c
>> @@ -562,6 +562,8 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
>>   	if (fs_info->fs_devices->latest_bdev == src_device->bdev)
>>   		fs_info->fs_devices->latest_bdev = tgt_device->bdev;
>>   	list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
>> +	if (src_device->fs_devices->seeding)
>> +		fs_info->fs_devices->rw_devices++;
>
> As I said in the previous version of this patch, we might increase ->rw_devices twice if
> the source device is a missing device in the seed filesystem. Once is here, the other is
> in btrfs_rm_dev_replace_srcdev().

   Yes that should be fixed. I think a separate patch will do since
   btrfs_rm_dev_replace_srcdev() is invariably incrementing the
   ->rw_devices without checking if the fs is a seed fs.

Anand

> Thanks
> Miao
>
>>
>>   	/* replace the sysfs entry */
>>   	btrfs_kobj_rm_device(fs_info, src_device);
>>
>
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>
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diff mbox

Patch

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index eea26e1..fb0a7fa 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -562,6 +562,8 @@  static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 	if (fs_info->fs_devices->latest_bdev == src_device->bdev)
 		fs_info->fs_devices->latest_bdev = tgt_device->bdev;
 	list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list);
+	if (src_device->fs_devices->seeding)
+		fs_info->fs_devices->rw_devices++;
 
 	/* replace the sysfs entry */
 	btrfs_kobj_rm_device(fs_info, src_device);