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Date:   Mon, 17 Jan 2022 21:32:44 -0500
From:   "Theodore Ts'o" <tytso@mit.edu>
To:     Yang Xu <xuyang2018.jy@fujitsu.com>
Cc:     fstests@vger.kernel.org
Subject: Re: [PATCH] src/ext4_resize.c: set errno to 0 before the strtoull
 call
Message-ID: <YeYmzJG5M0y9BcMc@mit.edu>
References: <1642405014-3287-1-git-send-email-xuyang2018.jy@fujitsu.com>
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On Mon, Jan 17, 2022 at 03:36:54PM +0800, Yang Xu wrote:
> On my test machine, ext4/033 fails even use the non-overflow size.
> It reports invalid new size when using strtoull because errno is 1.
> 
> As man-pages said "Since  strtoul()  can legitimately return 0 or ULONG_MAX
> (ULLONG_MAX for strtoull()) on both success and failure, the calling program
> should set errno to 0 before the call, and then determine if an error occurred
> by checking whether errno has a nonzero value after the call".
> 
> So add a step to set errno to 0 before strtoull call.
> 
> Fixes: 92b9c0dedace ("ext4/033: test EXT4_IOC_RESIZE_FS by calling the ioctl directly")
> Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>

Reviewed-by: Theodore Ts'o <tytso@mit.edu>

You're right of course, but out of curiosity, which C library are you
using?

						- Ted