Re: [PATCH]btrfs: Update existing btrfs_device for renaming device

[Yang Hongyang <yanghy@cn.fujitsu.com>]

TARUISI Hiroaki wrote:
> This patch updates device name in btrfs device.
> We can mount a device if its name are changed.
>=20
> Signed-off-by: TARUISI Hiroaki <taruishi.hiroak@jp.fujitsu.com>
> ---
>  fs/btrfs/volumes.c |    7 +++++++
>  1 file changed, 7 insertions(+)
>=20
> Index: b/fs/btrfs/volumes.c
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> --- a/fs/btrfs/volumes.c	2010-02-09 12:11:33.000000000 +0900
> +++ b/fs/btrfs/volumes.c	2010-02-09 12:43:29.000000000 +0900
> @@ -365,6 +365,7 @@ static noinline int device_list_add(cons
>  	struct btrfs_device *device;
>  	struct btrfs_fs_devices *fs_devices;
>  	u64 found_transid =3D btrfs_super_generation(disk_super);
> +	char *name;
>=20
>  	fs_devices =3D find_fsid(disk_super->fsid);
>  	if (!fs_devices) {
> @@ -411,6 +412,12 @@ static noinline int device_list_add(cons
>=20
>  		device->fs_devices =3D fs_devices;
>  		fs_devices->num_devices++;
> +	} else if (strcmp(device->name, path)) {
> +		name =3D kstrdup(path, GFP_NOFS);
> +		if (!device->name)

		It should be "if (!name)" here?

> +			return -ENOMEM;
> +		kfree(device->name);
> +		device->name =3D name;
>  	}
>=20
>  	if (found_transid > fs_devices->latest_trans) {
>=20
> (2009/11/08 6:44), Gustavo Alves wrote:
>> Hi Chris,
>>
>> I found the same problem on 2.6.32-0.33.rc5.git1 with btrfs-progs
>> 0.19. This problem is already fixed?
>>
>> Thanks
>>
>> ----
>> Gustavo Junior Alves
>> Specchio Solu=E7=F5es em TI
>> http://specchio.inf.br
>> Tel: +55 19 9223-0500
>>
>>
>>> From: Chris Mason <chris.mason_=E4t_oracle.com>
>>> Date: Tue, 07 Apr 2009 07:35:56 -0400
>>>
>>> On Mon, 2009-04-06 at 18:41 +0100, Hugo Mills wrote:
>>>> There seems to be some issue over changing the names of the device
>>>> that a btrfs filesystem lives on:
>>>>
>>>> # lvcreate scratch -n fstest -L 2G
>>>> Logical volume "fstest" created
>>>> # mkfs -t btrfs /dev/scratch/fstest
>>>>
>>>> WARNING! - Btrfs v0.18-ge3b0f66 IS EXPERIMENTAL
>>>> WARNING! - see http://btrfs.wiki.kernel.org before using
>>>>
>>>> fs created label (null) on /dev/scratch/fs1
>>>> nodesize 4096 leafsize 4096 sectorsize 4096 size 2.00GB
>>>> Btrfs v0.18-ge3b0f66
>>>>
>>>> # mount /dev/scratch/fstest /mnt
>>>> # umount /mnt
>>>>
>>>> # lvrename scratch fstest derek
>>>> Renamed "fstest" to "derek" in volume group "scratch"
>>>> # mount /dev/scratch/derek /mnt
>>>> mount: /dev/mapper/scratch-derek: can't read superblock
>>>>
>>>> # lvrename scratch derek fstest
>>>> Renamed "derek" to "fstest" in volume group "scratch"
>>>> # mount /dev/scratch/fstest /mnt
>>>> [success]
>>>>
>>>> The rename works properly on a completely virgin filesystem, but
>>>> not on one that's been mounted and unmounted (as above).
>>> Whoops, we need to reset the pathname when a probe finds a given de=
v
>>> uuid on a given device. I'll patch it up when I get back next week.
>>>
>>> Thanks for this bug report.
>>>
>>> -chris
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>=20
>=20


--=20
Regards
Yang Hongyang
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