[Cluster-devel] [GFS2 PATCH v2] GFS2: Check if iopen is held when deleting inode

[Steven Whitehouse]

Hi,

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

Steve.

On 12/01/16 15:25, Bob Peterson wrote:
> Hi,
>
> On 18 December 2015, I posted this upstream GFS2 patch. Since that time,
> I discovered a bug that warrants expanding the scope of the patch.
> This is the revised patch.
>
> Patch description:
>
> GFS2: Check if iopen is held when deleting inode
>
> This patch fixes an error condition in which an inode is partially
> created in gfs2_create_inode() but then some error is discovered,
> which causes it to fail and call iput() before the iopen glock is
> created or held. In that case, gfs2_delete_inode would try to
> unlock an iopen glock that doesn't yet exist. Therefore, we test
> its holder (which must exist) for the HIF_HOLDER bit before trying
> to dq it.
>
> Signed-off-by: Bob Peterson <rpeterso at redhat.com>
>
> diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
> index 795c2f3..8dedece 100644
> --- a/fs/gfs2/glock.c
> +++ b/fs/gfs2/glock.c
> @@ -1015,6 +1015,7 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
>   		handle_callback(gl, LM_ST_UNLOCKED, 0, false);
>   
>   	list_del_init(&gh->gh_list);
> +	clear_bit(HIF_HOLDER, &gh->gh_iflags);
>   	if (find_first_holder(gl) == NULL) {
>   		if (glops->go_unlock) {
>   			GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
> diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
> index 8f960a5..f8a0cd8 100644
> --- a/fs/gfs2/super.c
> +++ b/fs/gfs2/super.c
> @@ -1551,12 +1551,16 @@ static void gfs2_evict_inode(struct inode *inode)
>   			goto out_truncate;
>   	}
>   
> -	ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
> -	gfs2_glock_dq_wait(&ip->i_iopen_gh);
> -	gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE, &ip->i_iopen_gh);
> -	error = gfs2_glock_nq(&ip->i_iopen_gh);
> -	if (error)
> -		goto out_truncate;
> +	if (ip->i_iopen_gh.gh_gl &&
> +	    test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
> +		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
> +		gfs2_glock_dq_wait(&ip->i_iopen_gh);
> +		gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE,
> +				   &ip->i_iopen_gh);
> +		error = gfs2_glock_nq(&ip->i_iopen_gh);
> +		if (error)
> +			goto out_truncate;
> +	}
>   
>   	/* Case 1 starts here */
>   
> @@ -1606,11 +1610,13 @@ out_unlock:
>   	if (gfs2_rs_active(&ip->i_res))
>   		gfs2_rs_deltree(&ip->i_res);
>   
> -	if (test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
> -		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
> -		gfs2_glock_dq_wait(&ip->i_iopen_gh);
> +	if (ip->i_iopen_gh.gh_gl) {
> +		if (test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
> +			ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
> +			gfs2_glock_dq_wait(&ip->i_iopen_gh);
> +		}
> +		gfs2_holder_uninit(&ip->i_iopen_gh);
>   	}
> -	gfs2_holder_uninit(&ip->i_iopen_gh);
>   	gfs2_glock_dq_uninit(&gh);
>   	if (error && error != GLR_TRYFAILED && error != -EROFS)
>   		fs_warn(sdp, "gfs2_evict_inode: %d\n", error);
>