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From: "Yan, Zheng " <yanzheng@21cn.com>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: Chris Mason <chris.mason@oracle.com>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH 12/12] Btrfs: Fix file clone when source offset is not 0
Date: Thu, 2 Feb 2012 14:44:08 +0800	[thread overview]
Message-ID: <CAAM7YAk7xa7BVov5LdHgEzsTJF7+ot4yk53NVavS2SPvnqNqKw@mail.gmail.com> (raw)
In-Reply-To: <4F2A1FA5.9020606@cn.fujitsu.com>

On Thu, Feb 2, 2012 at 1:31 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
> Yan, Zheng wrote:
>> On Thu, Jan 27, 2011 at 4:46 PM, Li Zefan <lizf@cn.fujitsu.com> wrot=
e:
>>> Suppose:
>>> - the source extent is: [0, 100]
>>> - the src offset is 10
>>> - the clone length is 90
>>> - the dest offset is 0
>>>
>>> This statement:
>>>
>>> =A0 =A0 =A0 =A0new_key.offset =3D key.offset + destoff - off
>>>
>>> will produce such an extent for the dest file:
>>>
>>> =A0 =A0 =A0 =A0[ino, BTRFS_EXTENT_DATA_KEY, -10]
>>>
>>> , which is obviously wrong.
>>>
>>> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
>>> ---
>>> =A0fs/btrfs/ioctl.c | =A0 =A05 ++++-
>>> =A01 files changed, 4 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>>> index f87552a..1b61dab 100644
>>> --- a/fs/btrfs/ioctl.c
>>> +++ b/fs/btrfs/ioctl.c
>>> @@ -1788,7 +1788,10 @@ static noinline long btrfs_ioctl_clone(struc=
t file *file, unsigned long srcfd,
>>>
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0memcpy(&new_key, &ke=
y, sizeof(new_key));
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0new_key.objectid =3D=
 inode->i_ino;
>>> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 new_key.offset =3D ke=
y.offset + destoff - off;
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 if (off <=3D key.offs=
et)
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 new_k=
ey.offset =3D key.offset + destoff - off;
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 else
>>> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 new_k=
ey.offset =3D destoff;
>>>
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0trans =3D btrfs_star=
t_transaction(root, 1);
>>> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0if (IS_ERR(trans)) {
>>
>> This is a disk format change, will cause Oops when deleting or
>> truncating the file.
>>
>
> This is a bug fix, never mean to make a change on disk format. I'll
> appreciate if you point out what exactly is wrong in this fix.

sorry, I was misleaded by the backref discuss, your fix is correct
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  reply	other threads:[~2012-02-02  6:44 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-27  8:42 [PATCH 00/12] Btrfs: Some bug fixes Li Zefan
2011-01-27  8:42 ` [PATCH 01/12] btrfs: Fix threshold calculation for block groups smaller than 1GB Li Zefan
2011-01-27  8:42 ` [PATCH 02/12] btrfs: Add helper function free_bitmap() Li Zefan
2011-01-27  8:43 ` [PATCH 03/12] btrfs: Free fully occupied bitmap in cluster Li Zefan
2011-01-27  8:43 ` [PATCH 04/12] btrfs: Update stats when allocating from a cluster Li Zefan
2011-01-27  8:44 ` [PATCH 05/12] btrfs: Add a helper try_merge_free_space() Li Zefan
2011-01-27  8:44 ` [PATCH 06/12] btrfs: Check mergeable free space when removing a cluster Li Zefan
2011-01-27  8:44 ` [PATCH 07/12] Btrfs: Fix memory leak at umount Li Zefan
2011-01-27  8:44 ` [PATCH 08/12] Btrfs: Fix memory leak on finding existing super Li Zefan
2011-01-27  8:45 ` [PATCH 09/12] Btrfs: Free correct pointer after using strsep Li Zefan
2011-01-27  8:45 ` [PATCH 10/12] Btrfs: Don't return acl info when mounting with noacl option Li Zefan
2011-01-27  8:45 ` [PATCH 11/12] Btrfs: Fix memory leak in writepage fixup work Li Zefan
2011-01-27  8:46 ` [PATCH 12/12] Btrfs: Fix file clone when source offset is not 0 Li Zefan
2012-01-26 13:52   ` Jan Schmidt
2012-01-26 16:17     ` David Sterba
2012-01-30  6:33     ` Li Zefan
2012-01-30 10:03       ` Jan Schmidt
2012-02-01  9:44         ` Li Zefan
2012-02-02  4:31         ` Yan, Zheng 
2012-02-02 21:00           ` Jan Schmidt
2012-02-02  4:25   ` Yan, Zheng 
2012-02-02  5:31     ` Li Zefan
2012-02-02  6:44       ` Yan, Zheng  [this message]
2011-01-30 23:48 ` [PATCH 00/12] Btrfs: Some bug fixes Chris Mason

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