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From: "Nathaniel W. Turner" <nate@houseofnate.net>
To: xfs@oss.sgi.com
Subject: Re: XFS, empty files after a crash
Date: Thu, 23 Feb 2012 17:15:23 -0500	[thread overview]
Message-ID: <4F46BA7B.70600@houseofnate.net> (raw)
In-Reply-To: <4F469C7F.9020208@gmail.com>

On 02/23/2012 03:07 PM, kadafax@gmail.com wrote:
>
>> kfx, try getting the inode number of the file (via stat or ls -i) and then 
>> doing something like this:
>>
>> xfs_db -r $DEV -c "inode $INO" -c "bmap" 
>
>
> # xfs_db -r /dev/sdc1 -c "inode 114748" -c "bmap"
> data offset 0 startblock 1881705728 (7/2657536) count 6460 flag 0
>
> # xfs_db -r /dev/sdc1 -c "inode 114754" -c "bmap"
> data offset 0 startblock 1077794560 (4/4052736) count 6582 flag 0

If you want to see what's behind those data extents (which are probably 
partially written), you could do something along these lines:

# Determine the AG size
agblocks=$(xfs_db -r /dev/sdc1 -c sb -c p | grep ^agblocks | sed 's/.* = //')

# Copy the extent in the first file, which consists of 6460 blocks (~26MB)
# in AG 7 starting at AG-relative block 2657536:
dd if=/dev/sdc1 bs=4096 skip=$(($agblocks * 7 + 2657536)) count=6460 of=./blob
# examine ./blob
...

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  reply	other threads:[~2012-02-23 22:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-21 12:01 XFS, empty files after a crash kfx
2012-02-21 16:25 ` Peter Grandi
2012-02-22  3:18   ` Eric Sandeen
2012-02-23 19:38     ` Nathaniel W. Turner
2012-02-23 20:07       ` kadafax
2012-02-23 22:15         ` Nathaniel W. Turner [this message]
2012-02-24 10:21           ` kadafax
2012-02-21 17:39 ` Stan Hoeppner
2012-02-27  1:04 ` Dave Chinner
2012-02-27  8:43   ` kadafax
2012-02-28  1:39     ` Dave Chinner

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