[RFC,PATCH] libfs dcache_readdir() and dcache_dir_lseek() bugfix

jblunck_at_suse.de
Date: 11/04/05

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    Date:	Fri, 4 Nov 2005 12:38:51 +0100
To: linux-kernel@vger.kernel.org
"From:	jblunck@suse.de"

    This patch effects all users of libfs' dcache directory implementation.

    Old glibc implementations (e.g. glibc-2.2.5) are lseeking after every call to
    getdents(), subsequent calls to getdents() are starting to read from a wrong
    f_pos, when the directory is modified in between. Therefore not all directory
    entries are returned. IMHO this is a bug and it breaks applications, e.g. "rm
    -fr" on tmpfs.

    SuSV3 only says:
    "If a file is removed from or added to the directory after the most recent
    call to opendir() or rewinddir(), whether a subsequent call to readdir_r()
    returns an entry for that file is unspecified."

    Although I tried to provide a small fix, this is a complete rework of the
    libfs' dcache_readdir() and dcache_dir_lseek(). This patch use the dentries
    name hashes as the offsets for the directory entries. I'm not that sure it is
    maybe a problem to use full_name_hash() for that. If hash collisions occur,
    readdir() might return duplicate entries after an lseek(). Any ideas?

    This patch is compile and boot tested. This patch is against 2.6.14-git of
    today.

    Comments, please.
            Jan 

    -- 
Jan Blunck                                               jblunck@suse.de
SuSE LINUX AG - A Novell company
Maxfeldstr. 5                                          +49-911-74053-608
D-90409 Nürnberg                                      http://www.suse.de

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