[RFC] Btrfs design defect in extent backref ?

2011-08-25 Thread Li Zefan
We have an offset in file extent to indicate its position in the corresponding extent item in extent tree. We also have an offset in extent item to indicate the start position of the file extent that uses this item. The math is: extent_item.extent_data_ref.offset = file_pos -

Re: [RFC] Btrfs design defect in extent backref ?

2011-08-25 Thread Yan, Zheng
On Thu, Aug 25, 2011 at 3:56 PM, Li Zefan l...@cn.fujitsu.com wrote: We have an offset in file extent to indicate its position in the corresponding extent item in extent tree. We also have an offset in extent item to indicate the start position of the file extent that uses this item. The

Re: [RFC] Btrfs design defect in extent backref ?

2011-08-25 Thread Li Zefan
Yan, Zheng wrote: On Thu, Aug 25, 2011 at 3:56 PM, Li Zefan l...@cn.fujitsu.com wrote: We have an offset in file extent to indicate its position in the corresponding extent item in extent tree. We also have an offset in extent item to indicate the start position of the file extent that uses

Re: [RFC] Btrfs design defect in extent backref ?

2011-08-25 Thread Yan, Zheng
On Fri, Aug 26, 2011 at 10:00 AM, Li Zefan l...@cn.fujitsu.com wrote: Yan, Zheng wrote: On Thu, Aug 25, 2011 at 3:56 PM, Li Zefan l...@cn.fujitsu.com wrote: We have an offset in file extent to indicate its position in the corresponding extent item in extent tree. We also have an offset in

Re: [RFC] Btrfs design defect in extent backref ?

2011-08-25 Thread Li Zefan
Yan, Zheng wrote: On Fri, Aug 26, 2011 at 10:00 AM, Li Zefan l...@cn.fujitsu.com wrote: Yan, Zheng wrote: On Thu, Aug 25, 2011 at 3:56 PM, Li Zefan l...@cn.fujitsu.com wrote: We have an offset in file extent to indicate its position in the corresponding extent item in extent tree. We also