linux-ext4 - Re: e4defrag doesn't work on root filesystem

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Date:	Tue, 08 Sep 2009 08:42:13 -0500
From:	Ravi Pinjala <ravi@...tatic.net>
To:	Eric Sandeen <sandeen@...hat.com>
CC:	linux-ext4@...r.kernel.org
Subject: Re: e4defrag doesn't work on root filesystem

Eric Sandeen wrote:
> Ravi Pinjala wrote:
>> Hi,
>>
>> I'm playing with e4defrag from e2frprogs git, and I've run into a bug.
>> When I try to defragment files on my root filesystem, it refuses to
>> acknowledge that the filesystem is ext4. I believe the problem is that
>> it checks the filesystem type by parsing /etc/mtab, but the root
>> filesystem shows up there like this:
>>
>> rootfs on / type rootfs (rw)
>> /dev/root on / type ext4 (rw,noatime,barrier=1,data=ordered)
>>
>> so it gets confused by the bogus first entry. It works just fine on
>> other ext4 filesystems I have.
>>
>> (If this is the wrong mailing list, I apologize; I couldn't find one for
>> e2fsprogs, so I thought this was the next best thing.)
>>
>> --Ravi
>> -- 
>>   
> This list is a fine place to report it, thanks.
> 
> In is_ext4() it does a statfs on the file, and checks that the magic is
> EXT4,
> but then that's the same as ext2 and ext3 unfortunately  ....
> 
> It later does getmntent for the actual fs type, but fails, as you said.
> 
> Does this fix it for you?

Yeah, that works great. Thanks!

--Ravi

> 
> =========
> 
> Skip "rootfs" entry when checking for ext4 filesystem.
> 
> Signed-off-by: Eric Sandeen <sandeen@...hat.com>
> ---
> 
> diff --git a/misc/e4defrag.c b/misc/e4defrag.c
> index 82e3868..0d04df9 100644
> --- a/misc/e4defrag.c
> +++ b/misc/e4defrag.c
> @@ -430,6 +430,8 @@ static int is_ext4(const char *file)
>     }
> 
>     while ((mnt = getmntent(fp)) != NULL) {
> +        if (mnt->mnt_fsname[0] != '/')
> +            continue;
>         len = strlen(mnt->mnt_dir);
>         ret = memcmp(file_path, mnt->mnt_dir, len);
>         if (ret != 0)
> 
> 
> -- 
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