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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Frank Sorenson <sorenson@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, dwysocha@redhat.com, lvaz@redhat.com
Subject: Re: [PATCH 3/5] fs: add trace events for freeze_super() and thaw_super()
Date: Wed, 2 Mar 2016 20:12:15 +0000	[thread overview]
Message-ID: <20160302201215.GL17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1456945319-16283-4-git-send-email-sorenson@redhat.com>

On Wed, Mar 02, 2016 at 01:01:57PM -0600, Frank Sorenson wrote:
> There is currently no visibility into when or how
> a filesystem became frozen, and no record of freeze/
> thaw activity.  Add tracepoints for these events.

NAK.

> +	TP_fast_assign(
> +		memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
> +		memcpy(__entry->super_id, sb->s_id, SUPER_ID_MAX_LEN);
> +		memcpy(__entry->fstype, sb->s_type->name, FSTYPE_MAX_LEN);
> +		__entry->dev = sb->s_dev;
> +		__entry->frozen = sb->s_writers.frozen;

This turns the value of ->s_writers.frozen into a fucking userland ABI.
Committing us to maintain it forever.  No, thanks.

BTW, how is your "record the pid" supposed to interact with containers and
pidns?

  reply	other threads:[~2016-03-02 20:12 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-02 19:01 [PATCH 0/5] Add trace events for filesystem freeze/thaw events Frank Sorenson
2016-03-02 19:01 ` [PATCH 1/5] fs: simplify freeze_super()/thaw_super() exit handling Frank Sorenson
2016-03-02 20:06   ` Al Viro
2016-03-02 19:01 ` [PATCH 2/5] fs/block_dev.c: simplify freeze_bdev() and thaw_bdev() " Frank Sorenson
2016-03-02 19:01 ` [PATCH 3/5] fs: add trace events for freeze_super() and thaw_super() Frank Sorenson
2016-03-02 20:12   ` Al Viro [this message]
2016-03-02 19:01 ` [PATCH 4/5] fs/block_dev.c: add trace events for freeze_bdev() and thaw_bdev() Frank Sorenson
2016-03-02 19:01 ` [PATCH 5/5] fs: enable filesystem freeze/thaw events Frank Sorenson
2016-03-02 20:15   ` Al Viro
2016-03-02 21:47 ` [PATCH 0/5] Add trace events for " Al Viro
2016-03-02 22:47   ` Dave Chinner
2016-03-02 23:22     ` Al Viro
2016-03-02 23:52       ` Dave Chinner
2016-03-03 11:18 ` Dave Wysochanski

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