gfs2: dump fsid when dumping glock problems

Before this patch, if a glock error was encountered, the glock with
the problem was dumped. But sometimes you may have lots of file systems
mounted, and that doesn't tell you which file system it was for.

This patch adds a new boolean parameter fsid to the dump_glock family
of functions. For non-error cases, such as dumping the glocks debugfs
file, the fsid is not dumped in order to keep lock dumps and glocktop
as clean as possible. For all error cases, such as GLOCK_BUG_ON, the
file system id is now printed. This will make it easier to debug.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

1 files changed, 21 insertions, 13 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index f114a4045fcc..e23fb8b7b020 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1075,7 +1075,7 @@ trap_recursive:
 	fs_err(sdp, "pid: %d\n", pid_nr(gh->gh_owner_pid));
 	fs_err(sdp, "lock type: %d req lock state : %d\n",
 	       gh->gh_gl->gl_name.ln_type, gh->gh_state);
-	gfs2_dump_glock(NULL, gl);
+	gfs2_dump_glock(NULL, gl, true);
 	BUG();
 }
 
@@ -1610,16 +1610,16 @@ void gfs2_glock_thaw(struct gfs2_sbd *sdp)
 	glock_hash_walk(thaw_glock, sdp);
 }
 
-static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
+static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid)
 {
 	spin_lock(&gl->gl_lockref.lock);
-	gfs2_dump_glock(seq, gl);
+	gfs2_dump_glock(seq, gl, fsid);
 	spin_unlock(&gl->gl_lockref.lock);
 }
 
 static void dump_glock_func(struct gfs2_glock *gl)
 {
-	dump_glock(NULL, gl);
+	dump_glock(NULL, gl, true);
 }
 
 /**
@@ -1704,10 +1704,12 @@ static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
  * dump_holder - print information about a glock holder
  * @seq: the seq_file struct
  * @gh: the glock holder
+ * @fs_id_buf: pointer to file system id (if requested)
  *
  */
 
-static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
+static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh,
+			const char *fs_id_buf)
 {
 	struct task_struct *gh_owner = NULL;
 	char flags_buf[32];
@@ -1715,8 +1717,8 @@ static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
 	rcu_read_lock();
 	if (gh->gh_owner_pid)
 		gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
-	gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
-		       state2str(gh->gh_state),
+	gfs2_print_dbg(seq, "%s H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
+		       fs_id_buf, state2str(gh->gh_state),
 		       hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
 		       gh->gh_error,
 		       gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
@@ -1766,6 +1768,7 @@ static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
  * gfs2_dump_glock - print information about a glock
  * @seq: The seq_file struct
  * @gl: the glock
+ * @fsid: If true, also dump the file system id
  *
  * The file format is as follows:
  * One line per object, capital letters are used to indicate objects
@@ -1779,19 +1782,24 @@ static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
  *
  */
 
-void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
+void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid)
 {
 	const struct gfs2_glock_operations *glops = gl->gl_ops;
 	unsigned long long dtime;
 	const struct gfs2_holder *gh;
 	char gflags_buf[32];
+	char fs_id_buf[GFS2_FSNAME_LEN + 3 * sizeof(int) + 2];
+	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 
+	memset(fs_id_buf, 0, sizeof(fs_id_buf));
+	if (fsid && sdp) /* safety precaution */
+		sprintf(fs_id_buf, "fsid=%s: ", sdp->sd_fsname);
 	dtime = jiffies - gl->gl_demote_time;
 	dtime *= 1000000/HZ; /* demote time in uSec */
 	if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
 		dtime = 0;
-	gfs2_print_dbg(seq, "G:  s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d v:%d r:%d m:%ld\n",
-		  state2str(gl->gl_state),
+	gfs2_print_dbg(seq, "%sG:  s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d "
+		       "v:%d r:%d m:%ld\n", fs_id_buf, state2str(gl->gl_state),
 		  gl->gl_name.ln_type,
 		  (unsigned long long)gl->gl_name.ln_number,
 		  gflags2str(gflags_buf, gl),
@@ -1802,10 +1810,10 @@ void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
 		  (int)gl->gl_lockref.count, gl->gl_hold_time);
 
 	list_for_each_entry(gh, &gl->gl_holders, gh_list)
-		dump_holder(seq, gh);
+		dump_holder(seq, gh, fs_id_buf);
 
 	if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
-		glops->go_dump(seq, gl);
+		glops->go_dump(seq, gl, fs_id_buf);
 }
 
 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
@@ -2006,7 +2014,7 @@ static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
 
 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
 {
-	dump_glock(seq, iter_ptr);
+	dump_glock(seq, iter_ptr, false);
 	return 0;
 }