[Ocfs2-devel] [patch 09/11] ocfs2: add ocfs2_try_rw_lock() and ocfs2_try_inode_lock()

[alex chen <alex.chen@huawei.com>]

Looks good to me.

On 2017/12/1 6:24, akpm at linux-foundation.org wrote:
> From: Gang He <ghe@suse.com>
> Subject: ocfs2: add ocfs2_try_rw_lock() and ocfs2_try_inode_lock()
> 
> Patch series "ocfs2: add nowait aio support".
> 
> VFS layer has introduced the non-blocking aio flag IOCB_NOWAIT, which
> tells the kernel to bail out if an AIO request will block for reasons such
> as file allocations, or writeback triggering, or would block while
> allocating requests while performing direct I/O.
> 
> Subsequently, pwritev2/preadv2 also can leverage this part of kernel code.
> So far, ext4/xfs/btrfs have supported this feature.  Add the related code
> for the ocfs2 file system.  
> 
> 
> This patch (of 3):
> 
> Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which will be
> used in non-blocking IO scenarios.
> 
> [ghe at suse.com: v2]
>   Link: https://urldefense.proofpoint.com/v2/url?u=http-3A__lkml.kernel.org_r_1511944612-2D9629-2D2-2Dgit-2Dsend-2Demail-2Dghe-40suse.com&d=DwICAg&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=C7gAd4uDxlAvTdc0vmU6X8CMk6L2iDY8-HD0qT6Fo7Y&m=W4UpDjVlWv5DIIPCelEteB-SienntqWxnPDHSOG7DBo&s=O9wstNpVrzaQNqjJyE21XFRb16ul0wQp9AtfJ4Jr9hI&e=
> Link: https://urldefense.proofpoint.com/v2/url?u=http-3A__lkml.kernel.org_r_1511775987-2D841-2D2-2Dgit-2Dsend-2Demail-2Dghe-40suse.com&d=DwICAg&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=C7gAd4uDxlAvTdc0vmU6X8CMk6L2iDY8-HD0qT6Fo7Y&m=W4UpDjVlWv5DIIPCelEteB-SienntqWxnPDHSOG7DBo&s=fhdJtmG-qeTxswCoTvc42Is_mJIFHda4B0pHag4jzFk&e=
> Signed-off-by: Gang He <ghe@suse.com>
Reviewed-by: Alex Chen <alex.chen@huawei.com>
> Cc: Mark Fasheh <mfasheh@versity.com>
> Cc: Joel Becker <jlbec@evilplan.org>
> Cc: Junxiao Bi <junxiao.bi@oracle.com>
> Cc: Joseph Qi <jiangqi903@gmail.com>
> Cc: Changwei Ge <ge.changwei@h3c.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  fs/ocfs2/dlmglue.c |   21 +++++++++++++++++++++
>  fs/ocfs2/dlmglue.h |    4 ++++
>  2 files changed, 25 insertions(+)
> 
> diff -puN fs/ocfs2/dlmglue.c~ocfs2-add-ocfs2_try_rw_lock-and-ocfs2_try_inode_lock fs/ocfs2/dlmglue.c
> --- a/fs/ocfs2/dlmglue.c~ocfs2-add-ocfs2_try_rw_lock-and-ocfs2_try_inode_lock
> +++ a/fs/ocfs2/dlmglue.c
> @@ -1742,6 +1742,27 @@ int ocfs2_rw_lock(struct inode *inode, i
>  	return status;
>  }
>  
> +int ocfs2_try_rw_lock(struct inode *inode, int write)
> +{
> +	int status, level;
> +	struct ocfs2_lock_res *lockres;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +
> +	mlog(0, "inode %llu try to take %s RW lock\n",
> +	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
> +	     write ? "EXMODE" : "PRMODE");
> +
> +	if (ocfs2_mount_local(osb))
> +		return 0;
> +
> +	lockres = &OCFS2_I(inode)->ip_rw_lockres;
> +
> +	level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
> +
> +	status = ocfs2_cluster_lock(osb, lockres, level, DLM_LKF_NOQUEUE, 0);
> +	return status;
> +}
> +
>  void ocfs2_rw_unlock(struct inode *inode, int write)
>  {
>  	int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
> diff -puN fs/ocfs2/dlmglue.h~ocfs2-add-ocfs2_try_rw_lock-and-ocfs2_try_inode_lock fs/ocfs2/dlmglue.h
> --- a/fs/ocfs2/dlmglue.h~ocfs2-add-ocfs2_try_rw_lock-and-ocfs2_try_inode_lock
> +++ a/fs/ocfs2/dlmglue.h
> @@ -116,6 +116,7 @@ void ocfs2_lock_res_free(struct ocfs2_lo
>  int ocfs2_create_new_inode_locks(struct inode *inode);
>  int ocfs2_drop_inode_locks(struct inode *inode);
>  int ocfs2_rw_lock(struct inode *inode, int write);
> +int ocfs2_try_rw_lock(struct inode *inode, int write);
>  void ocfs2_rw_unlock(struct inode *inode, int write);
>  int ocfs2_open_lock(struct inode *inode);
>  int ocfs2_try_open_lock(struct inode *inode, int write);
> @@ -140,6 +141,9 @@ int ocfs2_inode_lock_with_page(struct in
>  /* 99% of the time we don't want to supply any additional flags --
>   * those are for very specific cases only. */
>  #define ocfs2_inode_lock(i, b, e) ocfs2_inode_lock_full_nested(i, b, e, 0, OI_LS_NORMAL)
> +#define ocfs2_try_inode_lock(i, b, e)\
> +		ocfs2_inode_lock_full_nested(i, b, e, OCFS2_META_LOCK_NOQUEUE,\
> +		OI_LS_NORMAL)
>  void ocfs2_inode_unlock(struct inode *inode,
>  		       int ex);
>  int ocfs2_super_lock(struct ocfs2_super *osb,
> _
> 
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