linux-kernel - Re: ext4 iomap SEEK broken [was: [GIT PULL] ext4 updates for 4.15]

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Message-ID: <45062110-e80c-f1e8-3710-743c1ae4d232@suse.cz>
Date:   Mon, 12 Feb 2018 13:14:07 +0100
From:   Jiri Slaby <jslaby@...e.cz>
To:     Theodore Ts'o <tytso@....edu>, linux-kernel@...r.kernel.org,
        linux-ext4@...r.kernel.org, Christoph Hellwig <hch@...radead.org>
Subject: Re: ext4 iomap SEEK broken [was: [GIT PULL] ext4 updates for 4.15]

On 02/12/2018, 11:02 AM, Jiri Slaby wrote:
> Given this happens only on 32bit kernel, I assume some 32bit overflow.
> But I am unable to see it (yet).

Just to add, a diff of strace in good and bad kernels:
@@ -655,14 +655,4 @@
 _llseek(3, 4275568640, [4286054400], SEEK_DATA) = 0
 _llseek(3, 4286054400, [4288675840], SEEK_HOLE) = 0
 _llseek(3, 4288675840, [4299161600], SEEK_DATA) = 0
-_llseek(3, 4299161600, [4301783040], SEEK_HOLE) = 0
+_llseek(3, 4299161600, [4299161600], SEEK_HOLE) = 2621440

llseek returns a very invalid value when it comes to 0x100400000.

regards,
-- 
js
suse labs