-------- Original Message --------
Subject: [Question] disk_bytenr with multiple devices
From: Zhe Zhang <zhe.zhang.research@xxxxxxxxx>
To: linux-btrfs@xxxxxxxxxxxxxxx
Date: 2014年07月11日 02:21
When a btrfs has multiple devices (e.g. /dev/sdb, /dev/sdc), how
should I interpret disk_bytenr in btrfs_file_extent_item?
Does it depend on the striping config? Say I used raid0, then
disk_bytenr 0~64K will be on /dev/sdb, and 64K~128K on /dev/sdc?
Thanks,
Zhe
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https://btrfs.wiki.kernel.org/index.php/Data_Structures#btrfs_file_extent_item
As you can see in the btrfs wiki,
disk_bytenr is *logical* address in btrfs linear space. Not really on
disk address.
If you really want the address on device, you need to find the chunk
containing the address,
then the stripe in chunk item will show the raid profile and device
address on each device.
Thanks,
Qu
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