linux-ext4 - Re: [PATCH 1/3] e2fsck: Clarify overflow link count error message

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Message-Id: <23FB58CC-BE93-4602-8B1C-9DA06FAE0F1A@dilger.ca>
Date:   Wed, 5 Feb 2020 10:38:04 -0700
From:   Andreas Dilger <adilger@...ger.ca>
To:     Jan Kara <jack@...e.cz>
Cc:     Ted Tso <tytso@....edu>, linux-ext4@...r.kernel.org
Subject: Re: [PATCH 1/3] e2fsck: Clarify overflow link count error message

On Feb 5, 2020, at 3:01 AM, Jan Kara <jack@...e.cz> wrote:
> 
> When directory link count is set to overflow value (1) but during pass 4
> we find out the exact link count would fit, we either silently fix this
> (which is not great because e2fsck then reports the fs was modified but
> output doesn't indicate why in any way), or we report that link count is
> wrong and ask whether we should fix it (in case -n option was
> specified). The second case is even more misleading because it suggests
> non-trivial fs corruption which then gets silently fixed on the next
> run. Similarly to how we fix up other non-problems, just create a new
> error message for the case directory link count is not overflown anymore
> and always report it to clarify what is going on.
> 
> 
> diff --git a/e2fsck/problem.c b/e2fsck/problem.c
> index c7c0ba986006..cde369d03034 100644
> --- a/e2fsck/problem.c
> +++ b/e2fsck/problem.c
> @@ -2035,6 +2035,11 @@ static struct e2fsck_problem problem_table[] = {
> 	  N_("@d exceeds max links, but no DIR_NLINK feature in @S.\n"),
> 	  PROMPT_FIX, 0, 0, 0, 0 },
> 
> +	/* Directory ref count set to overflow but it doesn't have to be */

> +	{ PR_4_DIR_OVERFLOW_REF_COUNT,
> +	  N_("@d @i %i ref count set to overflow value %Il but could be exact value %N.  "),

IMHO, you don't need to print "value %Il" since that will always be "1"?
That would shorten the message to fit on a single line.

Also, lease keep the comment and the actual error message identical.
Otherwise, it is harder to find the PR_* number and the related code in
e2fsck when trying to debug a problem.  So the comment should be:

	/* Directory inode ref count set to overflow but could be exact value */

To be honest, I don't see the benefit of the @d, @i, etc. abbreviations
in the messages anymore.  The few bytes of space savings is IMHO outweighed
by the added complexity in understanding and finding the messages in the
code, and added complexity in e2fsck itself when printing the messages.


Cheers, Andreas






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