On 2017-04-12 12:44, Andrei Borzenkov wrote:
12.04.2017 14:20, Austin S. Hemmelgarn пишет:
On 2017-04-12 00:18, Chris Murphy wrote:
On Tue, Apr 11, 2017 at 3:00 PM, Adam Borowski <kilobyte@xxxxxxxxxx>
wrote:
On Tue, Apr 11, 2017 at 12:15:32PM -0700, Amin Hassani wrote:
I am working on a project with Btrfs and I was wondering if there is
any way to see the disk layout of the btrfs image. Let's assume I have
a read-only btrfs image with compression on and only using one disk
(no raid or anything). Is it possible to get a set of offset-lengths
for each file
While btrfs-specific ioctls give more information, you might want to
look at
FIEMAP (Documentation/filesystems/fiemap.txt) as it works on most
filesystems, not just btrfs. One interface to FIEMAP is provided in
"/usr/sbin/filefrag -v".
Good idea. Although, on Btrfs I'm pretty sure it reports the Btrfs
(internal) logical addressing; not the actual physical sector address
on the drive. So it depends on what the original poster is trying to
discover.
That said, there is a tool to translate that back, and depending on how
detailed you want to get, that may be more efficient than debug tree.
Could you give pointer to this tool? I use filefrag on bootinfoscript to
display physical disk offset of files of interest to bootloader. I was
not aware it shows logical offset which makes it kinda pointless.
Looking again, I think I was thinking of `btrfs inspect-internal
logical-resolve`, which actually is more like a reverse fiemap (you give
it a logical address, and it spits out paths to all the files that
include that logical address), so such a tool may not actually exist (at
least, not in the standard tools).
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
