lkml.org 
[lkml]   [2017]   [Nov]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [Ocfs2-devel] [PATCH 1/3] ocfs2: add ocfs2_try_rw_lock and ocfs2_try_inode_lock
Date
Hi Gang,

On 2017/11/27 17:48, Gang He wrote:
> Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which
> will be used in non-block IO scenarios.
>
> Signed-off-by: Gang He <ghe@suse.com>
> ---
> fs/ocfs2/dlmglue.c | 22 ++++++++++++++++++++++
> fs/ocfs2/dlmglue.h | 4 ++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index 4689940..5cfbd04 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -1742,6 +1742,28 @@ int ocfs2_rw_lock(struct inode *inode, int write)
> 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(OCFS2_SB(inode->i_sb), lockres, level,
> + DLM_LKF_NOQUEUE, 0);
> + return status;
> +}

The newly added function ocfs2_try_rw_lock almost has the same logic
with ocfs2_rw_lock.Is it possible to combine them into an unique one?
That will be more elegant.

Moreover, can you elaborate further why we need a *NOQUEUE* lock for
supporting non-block aio?

Why can't we wait for a while to grant a lock request? Is this necessary?

Thanks,
Changwei

> +
> void ocfs2_rw_unlock(struct inode *inode, int write)
> {
> int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
> diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
> index a7fc18b..05910fc 100644
> --- a/fs/ocfs2/dlmglue.h
> +++ b/fs/ocfs2/dlmglue.h
> @@ -116,6 +116,7 @@ void ocfs2_refcount_lock_res_init(struct ocfs2_lock_res *lockres,
> 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 inode *inode,
> /* 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,
>

\
 
 \ /
  Last update: 2017-11-28 02:55    [W:0.089 / U:1.508 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site