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Date:	Wed, 31 Aug 2011 00:12:40 +0200
From:	Bernd Schubert <>
To:	Bernd Schubert <>
CC:,,,,, "J. Bruce Fields" <>,
	Ted Ts'o <>
Subject: Re: [PATCH 0/4] 32/64 bit llseek hashes (v4)

On 08/17/2011 11:57 AM, Bernd Schubert wrote:
> With the ext3/ext4 directory index implementation hashes are used to specify
> offsets for llseek(). For compatibility with NFSv2 and 32-bit user space
> on 64-bit systems (kernel space) ext3/ext4 currently only return 32-bit
> hashes and therefore the probability of hash collisions for larger directories
> is rather high. As recently reported on the NFS mailing list that theoretical
> problem also happens on real systems:
> The following series adds two new f_mode flags to tell ext4
> to use 32-bit or 64-bit hash values for llseek() calls.
> These flags can then used by network file systems, such as NFS, to
> request 32-bit or 64-bit offsets (hashes).
> Version 4
> - Andreas noticed there was HAVE_IS_COMPAT_TASK instead of
>    CONFIG_COMPAT in the
>    "Return 32/64-bit dir name hash according to usage type"
>    patch
> Version 3:
> - remove patch "RFC: Remove check for a 32-bit cookie in nfsd4_readdir()",
>    I think Bruce wanted to take it seperately as bug fix. It should be applied
>    before applying the remaining NFS patches, as without it NFSv4 will always
>    fail with the new 64-bit ext4 seek hashes.
> - split "nfsd: vfs_llseek() with 32 or 64 bit offsets (hashes)" into two
>    two separate patches as suggested by Bruce, one patch to rename
>    'access' to 'may_flags'. And the remainder of the original patch to set
>    FMODE_32BITHASH/FMODE_64BITHASH flags and to introduce the new
> Version 2:
> - use f_mode instead of O_* flags and also in a separate patch
> - introduce EXT4_HTREE_EOF_32BIT and EXT4_HTREE_EOF_64BIT
> - fix SEEK_END in ext4_dir_llseek()
> - set f_mode flags in NFS code as early as possible and introduce a new
>    NFSD_MAY_64BIT_COOKIE flag for that


any chance you could take this series or at least ack the ext4 part? 
Bruce already acked the NFS patches.

	Acked-by: J. Bruce Fields <>

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