From: Jan Kara <jack@suse.cz>
To: Steve French <sfrench@samba.org>
Cc: linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Hole punch races in CIFS
Date: Thu, 22 Apr 2021 13:58:38 +0200 [thread overview]
Message-ID: <20210422115838.GG26221@quack2.suse.cz> (raw)
Hello,
I was looking into what protects CIFS from races between hole punching and
operations like page fault or readahead and AFAICT there's nothing to
prevent a race like:
CPU1 CPU2
smb3_fallocate()
smb3_punch_hole()
truncate_pagecache_range()
filemap_fault()
- loads old data into the
page cache
SMB2_ioctl(..., FSCTL_SET_ZERO_DATA, ...)
And now we have stale data in the page cache and if the page gets later
dirtied and written out, even persistent data corruption. Is there anything
I'm missing?
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
reply other threads:[~2021-04-22 11:58 UTC|newest]
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