[Cluster-devel] [PATCH 1/4] GFS2: Prevent delete work from occurring on glocks used for create

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

Acked-by: Steven Whitehouse <swhiteho@redhat.com>

Steve.


On 18/12/15 19:02, Bob Peterson wrote:
> This patch tries to prevent delete work (queued via iopen callback)
> from executing if the glock is currently being used to create
> a new inode.
>
> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
> ---
>   fs/gfs2/glock.c  | 7 +++++++
>   fs/gfs2/incore.h | 1 +
>   fs/gfs2/inode.c  | 7 ++++++-
>   3 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
> index a4ff7b5..cb5ed3a 100644
> --- a/fs/gfs2/glock.c
> +++ b/fs/gfs2/glock.c
> @@ -572,6 +572,12 @@ static void delete_work_func(struct work_struct *work)
>   	struct inode *inode;
>   	u64 no_addr = gl->gl_name.ln_number;
>   
> +	/* If someone's using this glock to create a new dinode, the block must
> +	   have been freed by another node, then re-used, in which case our
> +	   iopen callback is too late after the fact. Ignore it. */
> +	if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
> +		goto out;
> +
>   	ip = gl->gl_object;
>   	/* Note: Unsafe to dereference ip as we don't hold right refs/locks */
>   
> @@ -583,6 +589,7 @@ static void delete_work_func(struct work_struct *work)
>   		d_prune_aliases(inode);
>   		iput(inode);
>   	}
> +out:
>   	gfs2_glock_put(gl);
>   }
>   
> diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
> index 845fb09..a6a3389 100644
> --- a/fs/gfs2/incore.h
> +++ b/fs/gfs2/incore.h
> @@ -328,6 +328,7 @@ enum {
>   	GLF_LRU				= 13,
>   	GLF_OBJECT			= 14, /* Used only for tracing */
>   	GLF_BLOCKING			= 15,
> +	GLF_INODE_CREATING		= 16, /* Inode creation occurring */
>   };
>   
>   struct gfs2_glock {
> diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
> index 009b551..6cdafed 100644
> --- a/fs/gfs2/inode.c
> +++ b/fs/gfs2/inode.c
> @@ -592,7 +592,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
>   	struct inode *inode = NULL;
>   	struct gfs2_inode *dip = GFS2_I(dir), *ip;
>   	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
> -	struct gfs2_glock *io_gl;
> +	struct gfs2_glock *io_gl = NULL;
>   	int error, free_vfs_inode = 1;
>   	u32 aflags = 0;
>   	unsigned blocks = 1;
> @@ -729,6 +729,8 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
>   	if (error)
>   		goto fail_gunlock2;
>   
> +	BUG_ON(test_and_set_bit(GLF_INODE_CREATING, &io_gl->gl_flags));
> +
>   	error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, &ip->i_iopen_gh);
>   	if (error)
>   		goto fail_gunlock2;
> @@ -771,12 +773,15 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
>   	}
>   	gfs2_glock_dq_uninit(ghs);
>   	gfs2_glock_dq_uninit(ghs + 1);
> +	clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
>   	return error;
>   
>   fail_gunlock3:
>   	gfs2_glock_dq_uninit(&ip->i_iopen_gh);
>   	gfs2_glock_put(io_gl);
>   fail_gunlock2:
> +	if (io_gl)
> +		clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
>   	gfs2_glock_dq_uninit(ghs + 1);
>   fail_free_inode:
>   	if (ip->i_gl)