From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Peterson Date: Wed, 23 Aug 2017 11:27:22 -0400 (EDT) Subject: [Cluster-devel] [GFS2 PATCH] [v2] GFS2: Fix up some sparse warnings In-Reply-To: <359006668.1872591.1503066056464.JavaMail.zimbra@redhat.com> Message-ID: <150960766.1169716.1503502042099.JavaMail.zimbra@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi, I've been doing some investigation with regard to Andy Price's questions about the glock / rhashtable portion of this patch. It turns out that the rhashtable code in function glock_hash_walk was patterned after the code in function tipc_sk_reinit() in net/tips/socket.c. The loop in Andy's question was added recently by Herbert Xu in commit 40f9f439706073b4b0a654b3b99e18296b7990b3 and comments in that patch explain why the loop was added. This differs, however, from net/netlink/diag.c which does not have the loop. As far as I can tell, the difference between having and not having the loop comes down to what happens when an rhashtable resize event occurs: Would you rather have it (a) process some unpredictable number of glocks twice, or (b) skip some altogether? Since the callers of function glock_hash_walk are gfs2_glock_thaw and gfs2_gl_hash_clear, it makes more sense to me to process them twice than not at all. In doing this investigation, I found a bug in the original tipc code, and submitted a patch for it this morning. That bug was one I has proposed fixing with version 1 of this patch. I've therefore revised this patch to (a) use IS_ERR(gl) rather than just (gl) as Andy suggested. (b) Added a goto instead of using braces, so that it more closely matches the patched tipc code, and (c) got rid of some parenthesis to appease Andreas. Bob Peterson Patch description: ------------------ 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 --- diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index ffca19598525..4178417249c3 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1550,14 +1550,15 @@ static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp) do { gl = ERR_PTR(rhashtable_walk_start(&iter)); - if (gl) - continue; + if (IS_ERR(gl)) + goto walk_stop; while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl)) - if ((gl->gl_name.ln_sbd == sdp) && + if (gl->gl_name.ln_sbd == sdp && lockref_get_not_dead(&gl->gl_lockref)) examiner(gl); +walk_stop: rhashtable_walk_stop(&iter); } while (cond_resched(), gl == ERR_PTR(-EAGAIN)); @@ -1940,6 +1941,7 @@ 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 +1974,7 @@ 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"