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From: Kai Tomerius <kai@tomerius.de>
To: Theodore Ts'o <tytso@mit.edu>
Cc: "Bjørn Forsman" <bjorn.forsman@gmail.com>,
	dm-devel@redhat.com,
	"Ext4 Developers List" <linux-ext4@vger.kernel.org>,
	"Alan C. Assis" <acassis@gmail.com>,
	linux-embedded@vger.kernel.org
Subject: Re: [dm-devel] File system robustness
Date: Wed, 19 Jul 2023 12:51:39 +0200	[thread overview]
Message-ID: <20230719105138.GA19936@tomerius.de> (raw)
In-Reply-To: <20230718213212.GE3842864@mit.edu>

> In answer to Kai's original question, the setup that was described
> should be fine --- assuming high quality hardware.

I wonder how to judge that ... it's an eMMC supposedly complying to
some JEDEC standard, so it *should* be ok.

> ... if power is cut suddenly, the data used by the Flash
> Translation Layer can be corrupted, in which case data written months
> or years ago (not just recent data) could be lost.

At least I haven't observed anything like that up to now.

But on another aspect: how about the interaction between dm-integrity
and ext4? Sure, they each have their own journal, and they're
independent layers. Is there anything that could go wrong, say a block
that can't be recovered in the dm-integrity layer, causing ext4 to run
into trouble, e.g., an I/O error that prevents ext4 from mounting?

I assume tne answer is "No", but can I be sure?

Thx
regards
Kai

--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel


WARNING: multiple messages have this Message-ID (diff)
From: Kai Tomerius <kai@tomerius.de>
To: Theodore Ts'o <tytso@mit.edu>
Cc: "Alan C. Assis" <acassis@gmail.com>,
	"Bjørn Forsman" <bjorn.forsman@gmail.com>,
	linux-embedded@vger.kernel.org,
	"Ext4 Developers List" <linux-ext4@vger.kernel.org>,
	dm-devel@redhat.com
Subject: Re: File system robustness
Date: Wed, 19 Jul 2023 12:51:39 +0200	[thread overview]
Message-ID: <20230719105138.GA19936@tomerius.de> (raw)
In-Reply-To: <20230718213212.GE3842864@mit.edu>

> In answer to Kai's original question, the setup that was described
> should be fine --- assuming high quality hardware.

I wonder how to judge that ... it's an eMMC supposedly complying to
some JEDEC standard, so it *should* be ok.

> ... if power is cut suddenly, the data used by the Flash
> Translation Layer can be corrupted, in which case data written months
> or years ago (not just recent data) could be lost.

At least I haven't observed anything like that up to now.

But on another aspect: how about the interaction between dm-integrity
and ext4? Sure, they each have their own journal, and they're
independent layers. Is there anything that could go wrong, say a block
that can't be recovered in the dm-integrity layer, causing ext4 to run
into trouble, e.g., an I/O error that prevents ext4 from mounting?

I assume tne answer is "No", but can I be sure?

Thx
regards
Kai

  parent reply	other threads:[~2023-07-20  6:33 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20230717075035.GA9549@tomerius.de>
2023-07-17  9:08 ` [dm-devel] File system robustness Geert Uytterhoeven
2023-07-17  9:08   ` Geert Uytterhoeven
2023-07-17  9:08   ` Geert Uytterhoeven
     [not found] ` <CAG4Y6eTU=WsTaSowjkKT-snuvZwqWqnH3cdgGoCkToH02qEkgg@mail.gmail.com>
     [not found]   ` <20230718053017.GB6042@tomerius.de>
2023-07-18 12:56     ` [dm-devel] " Alan C. Assis
2023-07-18 12:56       ` Alan C. Assis
     [not found]     ` <CAEYzJUGC8Yj1dQGsLADT+pB-mkac0TAC-typAORtX7SQ1kVt+g@mail.gmail.com>
2023-07-18 13:04       ` [dm-devel] " Alan C. Assis
2023-07-18 13:04         ` Alan C. Assis
2023-07-18 14:47         ` [dm-devel] " Chris
2023-07-18 14:47           ` Chris
2023-07-18 21:32         ` [dm-devel] " Theodore Ts'o
2023-07-18 21:32           ` Theodore Ts'o
2023-07-19  6:22           ` [dm-devel] " Martin Steigerwald
2023-07-19  6:22             ` Martin Steigerwald
2023-07-20  4:20             ` [dm-devel] " Theodore Ts'o
2023-07-20  4:20               ` Theodore Ts'o
2023-07-20  7:55               ` [dm-devel] Nobarrier mount option (was: Re: File system robustness) Martin Steigerwald
2023-07-20  7:55                 ` Martin Steigerwald
2023-07-21 13:35                 ` [dm-devel] " Theodore Ts'o
2023-07-21 13:35                   ` Theodore Ts'o
2023-07-21 14:51                   ` [dm-devel] " Martin Steigerwald
2023-07-21 14:51                     ` Martin Steigerwald
2023-07-19 10:51           ` Kai Tomerius [this message]
2023-07-19 10:51             ` File system robustness Kai Tomerius
2023-07-20  4:41             ` [dm-devel] " Theodore Ts'o
2023-07-20  4:41               ` Theodore Ts'o

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