GFS2: Log the reason for log flushes in every log header

This patch just adds the capability for GFS2 to track which function
called gfs2_log_flush. This should make it easier to diagnose
problems based on the sequence of events found in the journals.

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

fs/gfs2/aops.c

@@ -448,7 +448,8 @@ static int gfs2_jdata_writepages(struct address_space *mapping,
 
 	ret = gfs2_write_cache_jdata(mapping, wbc);
 	if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
-		gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL);
+		gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
+			       GFS2_LFC_JDATA_WPAGES);
 		ret = gfs2_write_cache_jdata(mapping, wbc);
 	}
 	return ret;

fs/gfs2/file.c

@@ -247,7 +247,8 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
 	if ((flags ^ new_flags) & GFS2_DIF_JDATA) {
 		if (new_flags & GFS2_DIF_JDATA)
 			gfs2_log_flush(sdp, ip->i_gl,
-				       GFS2_LOG_HEAD_FLUSH_NORMAL);
+				       GFS2_LOG_HEAD_FLUSH_NORMAL |
+				       GFS2_LFC_SET_FLAGS);
 		error = filemap_fdatawrite(inode->i_mapping);
 		if (error)
 			goto out;

fs/gfs2/glops.c

@@ -107,7 +107,8 @@ static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
 	__gfs2_ail_flush(gl, 0, tr.tr_revokes);
 
 	gfs2_trans_end(sdp);
-	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL);
+	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
+		       GFS2_LFC_AIL_EMPTY_GL);
 }
 
 void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
@@ -128,7 +129,8 @@ void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
 		return;
 	__gfs2_ail_flush(gl, fsync, max_revokes);
 	gfs2_trans_end(sdp);
-	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL);
+	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
+		       GFS2_LFC_AIL_FLUSH);
 }
 
 /**
@@ -157,7 +159,8 @@ static void rgrp_go_sync(struct gfs2_glock *gl)
 		return;
 	GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);
 
-	gfs2_log_flush(sdp, gl, GFS2_LOG_HEAD_FLUSH_NORMAL);
+	gfs2_log_flush(sdp, gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
+		       GFS2_LFC_RGRP_GO_SYNC);
 	filemap_fdatawrite_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
 	error = filemap_fdatawait_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
 	mapping_set_error(mapping, error);
@@ -252,7 +255,8 @@ static void inode_go_sync(struct gfs2_glock *gl)
 
 	GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);
 
-	gfs2_log_flush(gl->gl_name.ln_sbd, gl, GFS2_LOG_HEAD_FLUSH_NORMAL);
+	gfs2_log_flush(gl->gl_name.ln_sbd, gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
+		       GFS2_LFC_INODE_GO_SYNC);
 	filemap_fdatawrite(metamapping);
 	if (isreg) {
 		struct address_space *mapping = ip->i_inode.i_mapping;
@@ -304,7 +308,8 @@ static void inode_go_inval(struct gfs2_glock *gl, int flags)
 
 	if (ip == GFS2_I(gl->gl_name.ln_sbd->sd_rindex)) {
 		gfs2_log_flush(gl->gl_name.ln_sbd, NULL,
-			       GFS2_LOG_HEAD_FLUSH_NORMAL);
+			       GFS2_LOG_HEAD_FLUSH_NORMAL |
+			       GFS2_LFC_INODE_GO_INVAL);
 		gl->gl_name.ln_sbd->sd_rindex_uptodate = 0;
 	}
 	if (ip && S_ISREG(ip->i_inode.i_mode))
@@ -496,7 +501,8 @@ static void freeze_go_sync(struct gfs2_glock *gl)
 			gfs2_assert_withdraw(sdp, 0);
 		}
 		queue_work(gfs2_freeze_wq, &sdp->sd_freeze_work);
-		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE);
+		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE |
+			       GFS2_LFC_FREEZE_GO_SYNC);
 	}
 }
 

fs/gfs2/log.c

@@ -757,7 +757,7 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags)
  * gfs2_log_flush - flush incore transaction(s)
  * @sdp: the filesystem
  * @gl: The glock structure to flush.  If NULL, flush the whole incore log
- * @flags: The log header flags: GFS2_LOG_HEAD_FLUSH_*
+ * @flags: The log header flags: GFS2_LOG_HEAD_FLUSH_* and debug flags
  *
  */
 
@@ -773,7 +773,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 		up_write(&sdp->sd_log_flush_lock);
 		return;
 	}
-	trace_gfs2_log_flush(sdp, 1);
+	trace_gfs2_log_flush(sdp, 1, flags);
 
 	if (flags & GFS2_LOG_HEAD_FLUSH_SHUTDOWN)
 		clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
@@ -841,7 +841,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 			atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
 	}
 
-	trace_gfs2_log_flush(sdp, 0);
+	trace_gfs2_log_flush(sdp, 0, flags);
 	up_write(&sdp->sd_log_flush_lock);
 
 	kfree(tr);
@@ -937,7 +937,7 @@ void gfs2_log_shutdown(struct gfs2_sbd *sdp)
 
 	sdp->sd_log_flush_head = sdp->sd_log_head;
 
-	log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT);
+	log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT | GFS2_LFC_SHUTDOWN);
 
 	gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
 	gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
@@ -993,7 +993,8 @@ int gfs2_logd(void *data)
 		did_flush = false;
 		if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
 			gfs2_ail1_empty(sdp);
-			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL);
+			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
+				       GFS2_LFC_LOGD_JFLUSH_REQD);
 			did_flush = true;
 		}
 
@@ -1001,7 +1002,8 @@ int gfs2_logd(void *data)
 			gfs2_ail1_start(sdp);
 			gfs2_ail1_wait(sdp);
 			gfs2_ail1_empty(sdp);
-			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL);
+			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
+				       GFS2_LFC_LOGD_AIL_FLUSH_REQD);
 			did_flush = true;
 		}
 

fs/gfs2/ops_fstype.c

@@ -1382,7 +1382,7 @@ static void gfs2_kill_sb(struct super_block *sb)
 		return;
 	}
 
-	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SYNC);
+	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SYNC | GFS2_LFC_KILL_SB);
 	dput(sdp->sd_root_dir);
 	dput(sdp->sd_master_dir);
 	sdp->sd_root_dir = NULL;

fs/gfs2/quota.c

@@ -956,7 +956,7 @@ out:
 	inode_unlock(&ip->i_inode);
 	kfree(ghs);
 	gfs2_log_flush(ip->i_gl->gl_name.ln_sbd, ip->i_gl,
-		       GFS2_LOG_HEAD_FLUSH_NORMAL);
+		       GFS2_LOG_HEAD_FLUSH_NORMAL | GFS2_LFC_DO_SYNC);
 	return error;
 }
 

fs/gfs2/rgrp.c

@@ -2093,7 +2093,8 @@ next_rgrp:
 		}
 		/* Flushing the log may release space */
 		if (loops == 2)
-			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL);
+			gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
+				       GFS2_LFC_INPLACE_RESERVE);
 	}
 
 	return -ENOSPC;

fs/gfs2/super.c

@@ -758,7 +758,8 @@ static int gfs2_write_inode(struct inode *inode, struct writeback_control *wbc)
 
 	if (flush_all)
 		gfs2_log_flush(GFS2_SB(inode), ip->i_gl,
-			       GFS2_LOG_HEAD_FLUSH_NORMAL);
+			       GFS2_LOG_HEAD_FLUSH_NORMAL |
+			       GFS2_LFC_WRITE_INODE);
 	if (bdi->wb.dirty_exceeded)
 		gfs2_ail1_flush(sdp, wbc);
 	else
@@ -854,7 +855,8 @@ static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
 	gfs2_quota_sync(sdp->sd_vfs, 0);
 	gfs2_statfs_sync(sdp->sd_vfs, 0);
 
-	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SHUTDOWN);
+	gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SHUTDOWN |
+		       GFS2_LFC_MAKE_FS_RO);
 	wait_event(sdp->sd_reserving_log_wait, atomic_read(&sdp->sd_reserving_log) == 0);
 	gfs2_assert_warn(sdp, atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks);
 
@@ -947,7 +949,8 @@ static int gfs2_sync_fs(struct super_block *sb, int wait)
 
 	gfs2_quota_sync(sb, -1);
 	if (wait)
-		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL);
+		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
+			       GFS2_LFC_SYNC_FS);
 	return sdp->sd_log_error;
 }
 
@@ -1651,7 +1654,8 @@ alloc_failed:
 	goto out_unlock;
 
 out_truncate:
-	gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL);
+	gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
+		       GFS2_LFC_EVICT_INODE);
 	metamapping = gfs2_glock2aspace(ip->i_gl);
 	if (test_bit(GLF_DIRTY, &ip->i_gl->gl_flags)) {
 		filemap_fdatawrite(metamapping);

fs/gfs2/trace_gfs2.h

@@ -353,26 +353,29 @@ TRACE_EVENT(gfs2_pin,
 /* Flushing the log */
 TRACE_EVENT(gfs2_log_flush,
 
-	TP_PROTO(const struct gfs2_sbd *sdp, int start),
+	TP_PROTO(const struct gfs2_sbd *sdp, int start, u32 flags),
 
-	TP_ARGS(sdp, start),
+	TP_ARGS(sdp, start, flags),
 
 	TP_STRUCT__entry(
 		__field(        dev_t,  dev                     )
 		__field(	int,	start			)
 		__field(	u64,	log_seq			)
+		__field(	u32,	flags			)
 	),
 
 	TP_fast_assign(
 		__entry->dev            = sdp->sd_vfs->s_dev;
 		__entry->start		= start;
 		__entry->log_seq	= sdp->sd_log_sequence;
+		__entry->flags		= flags;
 	),
 
-	TP_printk("%u,%u log flush %s %llu",
+	TP_printk("%u,%u log flush %s %llu %llx",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->start ? "start" : "end",
-		  (unsigned long long)__entry->log_seq)
+		  (unsigned long long)__entry->log_seq,
+		  (unsigned long long)__entry->flags)
 );
 
 /* Reserving/releasing blocks in the log */

fs/gfs2/trans.c

@@ -117,7 +117,8 @@ void gfs2_trans_end(struct gfs2_sbd *sdp)
 	up_read(&sdp->sd_log_flush_lock);
 
 	if (sdp->sd_vfs->s_flags & SB_SYNCHRONOUS)
-		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL);
+		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
+			       GFS2_LFC_TRANS_END);
 	if (alloced)
 		sb_end_intwrite(sdp->sd_vfs);
 }

include/uapi/linux/gfs2_ondisk.h

@@ -411,6 +411,27 @@ struct gfs2_ea_header {
 #define GFS2_LOG_HEAD_RECOVERY		0x00000020 /* Journal recovery */
 #define GFS2_LOG_HEAD_USERSPACE		0x80000000 /* Written by gfs2-utils */
 
+/* Log flush callers */
+#define GFS2_LFC_SHUTDOWN		0x00000100
+#define GFS2_LFC_JDATA_WPAGES		0x00000200
+#define GFS2_LFC_SET_FLAGS		0x00000400
+#define GFS2_LFC_AIL_EMPTY_GL		0x00000800
+#define GFS2_LFC_AIL_FLUSH		0x00001000
+#define GFS2_LFC_RGRP_GO_SYNC		0x00002000
+#define GFS2_LFC_INODE_GO_SYNC		0x00004000
+#define GFS2_LFC_INODE_GO_INVAL		0x00008000
+#define GFS2_LFC_FREEZE_GO_SYNC		0x00010000
+#define GFS2_LFC_KILL_SB		0x00020000
+#define GFS2_LFC_DO_SYNC		0x00040000
+#define GFS2_LFC_INPLACE_RESERVE	0x00080000
+#define GFS2_LFC_WRITE_INODE		0x00100000
+#define GFS2_LFC_MAKE_FS_RO		0x00200000
+#define GFS2_LFC_SYNC_FS		0x00400000
+#define GFS2_LFC_EVICT_INODE		0x00800000
+#define GFS2_LFC_TRANS_END		0x01000000
+#define GFS2_LFC_LOGD_JFLUSH_REQD	0x02000000
+#define GFS2_LFC_LOGD_AIL_FLUSH_REQD	0x04000000
+
 #define LH_V1_SIZE (offsetofend(struct gfs2_log_header, lh_hash))
 
 struct gfs2_log_header {