[Ocfs2-devel] [PATCH 1/1] Ocfs2: Teach 'coherency=full' O_DIRECT writes to correctly up_read i_alloc_sem.

[Tao Ma]

Hi Tristan,
	Your patch forgets to set the new flag properly in direct read.

Regards,
Tao
On 11/29/2010 03:54 PM, Tristan Ye wrote:
> Due to newly-introduced 'coherency=full' O_DIRECT writes also takes the EX
> rw_lock like buffered writes did(rw_level == 1), it turns out messing the
> usage of 'level' in ocfs2_dio_end_io() up, which caused i_alloc_sem being
> failed to get up_read'd correctly.
>
> This patch tries to teach ocfs2_dio_end_io to understand well on all locking
> stuffs by explicitly introducing a new bit for i_alloc_sem in iocb's private
> data, just like what we did for rw_lock.

>
> Signed-off-by: Tristan Ye<tristan.ye at oracle.com>
> ---
>   fs/ocfs2/aops.c |    6 ++++--
>   fs/ocfs2/aops.h |    6 ++++++
>   fs/ocfs2/file.c |    5 ++++-
>   3 files changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index f1e962c..857e013 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -568,7 +568,7 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
>   			     bool is_async)
>   {
>   	struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
> -	int level;
> +	int level, sem_locked;
>
>   	/* this io's submitter should not have unlocked this before we could */
>   	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
> @@ -576,7 +576,9 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
>   	ocfs2_iocb_clear_rw_locked(iocb);
>
>   	level = ocfs2_iocb_rw_locked_level(iocb);
> -	if (!level)
> +	sem_locked = ocfs2_iocb_is_sem_locked(iocb);
> +	ocfs2_iocb_clear_sem_locked(iocb);
> +	if (sem_locked)
>   		up_read(&inode->i_alloc_sem);
>   	ocfs2_rw_unlock(inode, level);
>
> diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h
> index 76bfdfd..c7a3e5f 100644
> --- a/fs/ocfs2/aops.h
> +++ b/fs/ocfs2/aops.h
> @@ -72,4 +72,10 @@ static inline void ocfs2_iocb_set_rw_locked(struct kiocb *iocb, int level)
>   	clear_bit(0, (unsigned long *)&iocb->private)
>   #define ocfs2_iocb_rw_locked_level(iocb) \
>   	test_bit(1, (unsigned long *)&iocb->private)
> +#define ocfs2_iocb_set_sem_locked(iocb) \
> +	set_bit(2, (unsigned long *)&iocb->private)
> +#define ocfs2_iocb_clear_sem_locked(iocb) \
> +	clear_bit(2, (unsigned long *)&iocb->private)
> +#define ocfs2_iocb_is_sem_locked(iocb) \
> +	test_bit(2, (unsigned long *)&iocb->private)
>   #endif /* OCFS2_FILE_H */
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index 77b4c04..4e66990 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -2246,7 +2246,10 @@ relock:
>   	if (direct_io) {
>   		down_read(&inode->i_alloc_sem);
>   		have_alloc_sem = 1;
> -	}
> +		/* communicate with ocfs2_dio_end_io */
> +		ocfs2_iocb_set_sem_locked(iocb);
> +	} else
> +		ocfs2_iocb_clear_sem_locked(iocb);
>
>   	/*
>   	 * Concurrent O_DIRECT writes are allowed with