Yan, Zheng wrote:
> On Thu, Jan 27, 2011 at 4:46 PM, Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:
>> Suppose:
>> - the source extent is: [0, 100]
>> - the src offset is 10
>> - the clone length is 90
>> - the dest offset is 0
>>
>> This statement:
>>
>> new_key.offset = key.offset + destoff - off
>>
>> will produce such an extent for the dest file:
>>
>> [ino, BTRFS_EXTENT_DATA_KEY, -10]
>>
>> , which is obviously wrong.
>>
>> Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
>> ---
>> fs/btrfs/ioctl.c | 5 ++++-
>> 1 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(struct file *file, unsigned long srcfd,
>>
>> memcpy(&new_key, &key, sizeof(new_key));
>> new_key.objectid = inode->i_ino;
>> - new_key.offset = key.offset + destoff - off;
>> + if (off <= key.offset)
>> + new_key.offset = key.offset + destoff - off;
>> + else
>> + new_key.offset = destoff;
>>
>> trans = btrfs_start_transaction(root, 1);
>> if (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.
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