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    Subject[patch 1/9] fs: make sure data stored into inode is properly seen before unlocking new inode
    2.6.27-stable review patch.  If anyone has any objections, please let us know.

    ------------------

    From: Jan Kara <jack@suse.cz>

    commit 580be0837a7a59b207c3d5c661d044d8dd0a6a30 upstream.

    In theory it could happen that on one CPU we initialize a new inode but
    clearing of I_NEW | I_LOCK gets reordered before some of the
    initialization. Thus on another CPU we return not fully uptodate inode
    from iget_locked().

    This seems to fix a corruption issue on ext3 mounted over NFS.

    [akpm@linux-foundation.org: add some commentary]
    Signed-off-by: Jan Kara <jack@suse.cz>
    Cc: Christoph Hellwig <hch@infradead.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    fs/inode.c | 14 ++++++++------
    1 file changed, 8 insertions(+), 6 deletions(-)

    --- a/fs/inode.c
    +++ b/fs/inode.c
    @@ -590,13 +590,15 @@ void unlock_new_inode(struct inode *inod
    }
    #endif
    /*
    - * This is special! We do not need the spinlock
    - * when clearing I_LOCK, because we're guaranteed
    - * that nobody else tries to do anything about the
    - * state of the inode when it is locked, as we
    - * just created it (so there can be no old holders
    - * that haven't tested I_LOCK).
    + * This is special! We do not need the spinlock when clearing I_LOCK,
    + * because we're guaranteed that nobody else tries to do anything about
    + * the state of the inode when it is locked, as we just created it (so
    + * there can be no old holders that haven't tested I_LOCK).
    + * However we must emit the memory barrier so that other CPUs reliably
    + * see the clearing of I_LOCK after the other inode initialisation has
    + * completed.
    */
    + smp_mb();
    WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW));
    inode->i_state &= ~(I_LOCK|I_NEW);
    wake_up_inode(inode);



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