[Cluster-devel] [GFS2 PATCH] GFS2: Fix up some sparse warnings

[Andrew Price <anprice@redhat.com>]

On Fri, Aug 18, 2017 at 10:20:56AM -0400, Bob Peterson wrote:
> Hi,
> 
> This patch cleans up various pieces of GFS2 to avoid sparse errors.
> This doesn't fix them all, but it fixes several. The first error,
> in function glock_hash_walk was a genuine bug where the rhashtable
> could be started and not stopped.
> 
> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
> ---
> diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
> index ffca19598525..db78720f3c89 100644
> --- a/fs/gfs2/glock.c
> +++ b/fs/gfs2/glock.c
> @@ -1550,14 +1550,13 @@ static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
>  
>  	do {
>  		gl = ERR_PTR(rhashtable_walk_start(&iter));

Couldn't the rhashtable_walk_start() call be moved before the outer loop?

"* Returns -EAGAIN if resize event occured.  Note that the iterator
 * will rewind back to the beginning and you may use it immediately
 * by calling rhashtable_walk_next."

so it looks like -EAGAIN doesn't require a stop and restart of the walk.

> -		if (gl)
> -			continue;
> -
> -		while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
> -			if ((gl->gl_name.ln_sbd == sdp) &&
> -			    lockref_get_not_dead(&gl->gl_lockref))
> -				examiner(gl);
> -
> +		if (!gl) {

This looks like it should be if (!IS_ERR(gl)) { ...

> +			while ((gl = rhashtable_walk_next(&iter)) &&
> +			       !IS_ERR(gl))
> +				if ((gl->gl_name.ln_sbd == sdp) &&
> +				    lockref_get_not_dead(&gl->gl_lockref))
> +					examiner(gl);
> +		}
>  		rhashtable_walk_stop(&iter);

See above.

Cheers,
Andy

>  	} while (cond_resched(), gl == ERR_PTR(-EAGAIN));
>  
> @@ -1940,6 +1939,7 @@ static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
>  }
>  
>  static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
> +	__acquires(RCU)
>  {
>  	struct gfs2_glock_iter *gi = seq->private;
>  	loff_t n = *pos;
> @@ -1972,6 +1972,7 @@ static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
>  }
>  
>  static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
> +	__releases(RCU)
>  {
>  	struct gfs2_glock_iter *gi = seq->private;
>  
> diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
> index 1d98b8a36eb3..65f33a0ac190 100644
> --- a/fs/gfs2/lock_dlm.c
> +++ b/fs/gfs2/lock_dlm.c
> @@ -23,8 +23,6 @@
>  #include "sys.h"
>  #include "trace_gfs2.h"
>  
> -extern struct workqueue_struct *gfs2_control_wq;
> -
>  /**
>   * gfs2_update_stats - Update time based stats
>   * @mv: Pointer to mean/variance structure to update
> @@ -1176,7 +1174,7 @@ static void gdlm_recovery_result(struct gfs2_sbd *sdp, unsigned int jid,
>  	spin_unlock(&ls->ls_recover_spin);
>  }
>  
> -const struct dlm_lockspace_ops gdlm_lockspace_ops = {
> +static const struct dlm_lockspace_ops gdlm_lockspace_ops = {
>  	.recover_prep = gdlm_recover_prep,
>  	.recover_slot = gdlm_recover_slot,
>  	.recover_done = gdlm_recover_done,
> diff --git a/fs/gfs2/main.c b/fs/gfs2/main.c
> index 0a89e6f7a314..899329cfd733 100644
> --- a/fs/gfs2/main.c
> +++ b/fs/gfs2/main.c
> @@ -32,8 +32,6 @@
>  #include "dir.h"
>  #include "glops.h"
>  
> -struct workqueue_struct *gfs2_control_wq;
> -
>  static void gfs2_init_inode_once(void *foo)
>  {
>  	struct gfs2_inode *ip = foo;
> diff --git a/fs/gfs2/util.h b/fs/gfs2/util.h
> index c81295f407f6..3926f95a6eb7 100644
> --- a/fs/gfs2/util.h
> +++ b/fs/gfs2/util.h
> @@ -151,6 +151,7 @@ extern struct kmem_cache *gfs2_rgrpd_cachep;
>  extern struct kmem_cache *gfs2_quotad_cachep;
>  extern struct kmem_cache *gfs2_qadata_cachep;
>  extern mempool_t *gfs2_page_pool;
> +extern struct workqueue_struct *gfs2_control_wq;
>  
>  static inline unsigned int gfs2_tune_get_i(struct gfs2_tune *gt,
>  					   unsigned int *p)
> diff --git a/fs/gfs2/xattr.c b/fs/gfs2/xattr.c
> index 54179554c7d2..cf694de4991a 100644
> --- a/fs/gfs2/xattr.c
> +++ b/fs/gfs2/xattr.c
> @@ -25,6 +25,7 @@
>  #include "meta_io.h"
>  #include "quota.h"
>  #include "rgrp.h"
> +#include "super.h"
>  #include "trans.h"
>  #include "util.h"
>  
>