From: Eric Sandeen <sandeen@redhat.com>
To: ext4 development <linux-ext4@vger.kernel.org>
Subject: RFC: "file" magic for ext4
Date: Wed, 30 Jan 2008 11:19:59 -0600 [thread overview]
Message-ID: <47A0B1BF.4010109@redhat.com> (raw)
This seems to work fine; any comments, either about
the logic, or the text descriptions, or the various
options I've shown/not shown?
To test, copy your "magic" file somewhere local,
replace the ext2/3 section with the following,
and do something like:
# file -C -m magic; file -m ./magic -s /dev/sda1
-Eric
# ext2/ext3 filesystems - Andreas Dilger <adilger@turbolabs.com>
0x438 leshort 0xEF53 Linux
>0x44c lelong x rev %d
>0x43e leshort x \b.%d
# No journal? ext2
>0x45c lelong ^0x0000004 ext2 filesystem data
>>0x43a leshort ^0x0000001 (mounted or unclean)
# Has a journal? ext3 or ext4
>0x45c lelong &0x0000004
# and small INCOMPAT?
>>0x460 lelong <0x0000040
# and small RO_COMPAT?
>>>0x464 lelong <0x0000008 ext3 filesystem data
# else large RO_COMPAT?
>>>0x464 lelong >0x0000007 ext4 filesystem data
# else large INCOMPAT?
>>0x460 lelong >0x000003f ext4 filesystem data
# General flags for any ext* fs
>0x460 lelong &0x0000004 (needs journal recovery)
>0x43a leshort &0x0000002 (errors)
# INCOMPAT flags
>0x460 lelong &0x0000001 (compressed)
#>0x460 lelong &0x0000002 (filetype)
#>0x460 lelong &0x0000010 (meta bg)
>0x460 lelong &0x0000040 (extents)
>0x460 lelong &0x0000080 (64bit)
#>0x460 lelong &0x0000100 (mmp)
#>0x460 lelong &0x0000200 (flex bg)
# RO_INCOMPAT flags
#>0x464 lelong &0x0000001 (sparse super)
>0x464 lelong &0x0000002 (large files)
>0x464 lelong &0x0000008 (huge files)
#>0x464 lelong &0x0000010 (gdt checksum)
#>0x464 lelong &0x0000020 (many subdirs)
#>0x463 lelong &0x0000040 (extra isize)
next reply other threads:[~2008-01-30 17:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-30 17:19 Eric Sandeen [this message]
2008-01-31 0:34 ` RFC: "file" magic for ext4 Andreas Dilger
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