GFS2: Add tracepoints

This patch adds the ability to trace various aspects of the GFS2
filesystem. The trace points are divided into three groups,
glocks, logging and bmap. These points have been chosen because
they allow inspection of the major internal functions of GFS2
and they are also generic enough that they are unlikely to need
any major changes as the filesystem evolves.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/Makefile

+EXTRA_CFLAGS := -I$(src)
 obj-$(CONFIG_GFS2_FS) += gfs2.o
 gfs2-y := acl.o bmap.o dir.o eaops.o eattr.o glock.o \
 	glops.o inode.o log.o lops.o main.o meta_io.o \

fs/gfs2/bmap.c

@@ -25,6 +25,7 @@
 #include "trans.h"
 #include "dir.h"
 #include "util.h"
+#include "trace_gfs2.h"
 
 /* This doesn't need to be that large as max 64 bit pointers in a 4k
  * block is 512, so __u16 is fine for that. It saves stack space to
@@ -589,6 +590,7 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
 	clear_buffer_mapped(bh_map);
 	clear_buffer_new(bh_map);
 	clear_buffer_boundary(bh_map);
+	trace_gfs2_bmap(ip, bh_map, lblock, create, 1);
 	if (gfs2_is_dir(ip)) {
 		bsize = sdp->sd_jbsize;
 		arr = sdp->sd_jheightsize;
@@ -623,6 +625,7 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
 	ret = 0;
 out:
 	release_metapath(&mp);
+	trace_gfs2_bmap(ip, bh_map, lblock, create, ret);
 	bmap_unlock(ip, create);
 	return ret;
 

fs/gfs2/glock.c

@@ -39,6 +39,8 @@
 #include "super.h"
 #include "util.h"
 #include "bmap.h"
+#define CREATE_TRACE_POINTS
+#include "trace_gfs2.h"
 
 struct gfs2_gl_hash_bucket {
         struct hlist_head hb_list;
@@ -155,7 +157,7 @@ static void glock_free(struct gfs2_glock *gl)
 
 	if (aspace)
 		gfs2_aspace_put(aspace);
-
+	trace_gfs2_glock_put(gl);
 	sdp->sd_lockstruct.ls_ops->lm_put_lock(gfs2_glock_cachep, gl);
 }
 
@@ -317,14 +319,17 @@ restart:
 						return 2;
 					gh->gh_error = ret;
 					list_del_init(&gh->gh_list);
+					trace_gfs2_glock_queue(gh, 0);
 					gfs2_holder_wake(gh);
 					goto restart;
 				}
 				set_bit(HIF_HOLDER, &gh->gh_iflags);
+				trace_gfs2_promote(gh, 1);
 				gfs2_holder_wake(gh);
 				goto restart;
 			}
 			set_bit(HIF_HOLDER, &gh->gh_iflags);
+			trace_gfs2_promote(gh, 0);
 			gfs2_holder_wake(gh);
 			continue;
 		}
@@ -354,6 +359,7 @@ static inline void do_error(struct gfs2_glock *gl, const int ret)
 		else
 			continue;
 		list_del_init(&gh->gh_list);
+		trace_gfs2_glock_queue(gh, 0);
 		gfs2_holder_wake(gh);
 	}
 }
@@ -422,6 +428,7 @@ static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
 	int rv;
 
 	spin_lock(&gl->gl_spin);
+	trace_gfs2_glock_state_change(gl, state);
 	state_change(gl, state);
 	gh = find_first_waiter(gl);
 
@@ -851,6 +858,7 @@ static void handle_callback(struct gfs2_glock *gl, unsigned int state,
 			gl->gl_demote_state != state) {
 		gl->gl_demote_state = LM_ST_UNLOCKED;
 	}
+	trace_gfs2_demote_rq(gl);
 }
 
 /**
@@ -936,6 +944,7 @@ fail:
 			goto do_cancel;
 		return;
 	}
+	trace_gfs2_glock_queue(gh, 1);
 	list_add_tail(&gh->gh_list, insert_pt);
 do_cancel:
 	gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
@@ -1032,6 +1041,7 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
 		    !test_bit(GLF_DEMOTE, &gl->gl_flags))
 			fast_path = 1;
 	}
+	trace_gfs2_glock_queue(gh, 0);
 	spin_unlock(&gl->gl_spin);
 	if (likely(fast_path))
 		return;

fs/gfs2/log.c

@@ -28,6 +28,7 @@
 #include "meta_io.h"
 #include "util.h"
 #include "dir.h"
+#include "trace_gfs2.h"
 
 #define PULL 1
 
@@ -313,6 +314,7 @@ int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 		gfs2_log_lock(sdp);
 	}
 	atomic_sub(blks, &sdp->sd_log_blks_free);
+	trace_gfs2_log_blocks(sdp, -blks);
 	gfs2_log_unlock(sdp);
 	mutex_unlock(&sdp->sd_log_reserve_mutex);
 
@@ -333,6 +335,7 @@ void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 
 	gfs2_log_lock(sdp);
 	atomic_add(blks, &sdp->sd_log_blks_free);
+	trace_gfs2_log_blocks(sdp, blks);
 	gfs2_assert_withdraw(sdp,
 			     atomic_read(&sdp->sd_log_blks_free) <= sdp->sd_jdesc->jd_blocks);
 	gfs2_log_unlock(sdp);
@@ -558,6 +561,7 @@ static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 
 	gfs2_log_lock(sdp);
 	atomic_add(dist, &sdp->sd_log_blks_free);
+	trace_gfs2_log_blocks(sdp, dist);
 	gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <= sdp->sd_jdesc->jd_blocks);
 	gfs2_log_unlock(sdp);
 
@@ -715,6 +719,7 @@ void __gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 		up_write(&sdp->sd_log_flush_lock);
 		return;
 	}
+	trace_gfs2_log_flush(sdp, 1);
 
 	ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
 	INIT_LIST_HEAD(&ai->ai_ail1_list);
@@ -746,6 +751,7 @@ void __gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 	else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
 		gfs2_log_lock(sdp);
 		atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
+		trace_gfs2_log_blocks(sdp, -1);
 		gfs2_log_unlock(sdp);
 		log_write_header(sdp, 0, PULL);
 	}
@@ -763,7 +769,7 @@ void __gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
 		ai = NULL;
 	}
 	gfs2_log_unlock(sdp);
-
+	trace_gfs2_log_flush(sdp, 0);
 	up_write(&sdp->sd_log_flush_lock);
 
 	kfree(ai);
@@ -787,6 +793,7 @@ static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 	gfs2_assert_withdraw(sdp, sdp->sd_log_blks_reserved + tr->tr_reserved >= reserved);
 	unused = sdp->sd_log_blks_reserved - reserved + tr->tr_reserved;
 	atomic_add(unused, &sdp->sd_log_blks_free);
+	trace_gfs2_log_blocks(sdp, unused);
 	gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 			     sdp->sd_jdesc->jd_blocks);
 	sdp->sd_log_blks_reserved = reserved;

fs/gfs2/lops.c

@@ -27,6 +27,7 @@
 #include "rgrp.h"
 #include "trans.h"
 #include "util.h"
+#include "trace_gfs2.h"
 
 /**
  * gfs2_pin - Pin a buffer in memory
@@ -53,6 +54,7 @@ static void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
 	if (bd->bd_ail)
 		list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
 	get_bh(bh);
+	trace_gfs2_pin(bd, 1);
 }
 
 /**
@@ -89,6 +91,7 @@ static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
 	bd->bd_ail = ai;
 	list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
 	clear_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
+	trace_gfs2_pin(bd, 0);
 	gfs2_log_unlock(sdp);
 	unlock_buffer(bh);
 }

fs/gfs2/ops_fstype.c

@@ -33,6 +33,7 @@
 #include "log.h"
 #include "quota.h"
 #include "dir.h"
+#include "trace_gfs2.h"
 
 #define DO 0
 #define UNDO 1
@@ -775,6 +776,7 @@ static int init_journal(struct gfs2_sbd *sdp, int undo)
 		/* Map the extents for this journal's blocks */
 		map_journal_extents(sdp);
 	}
+	trace_gfs2_log_blocks(sdp, atomic_read(&sdp->sd_log_blks_free));
 
 	if (sdp->sd_lockstruct.ls_first) {
 		unsigned int x;

fs/gfs2/rgrp.c

@@ -29,6 +29,7 @@
 #include "util.h"
 #include "log.h"
 #include "inode.h"
+#include "trace_gfs2.h"
 
 #define BFITNOENT ((u32)~0)
 #define NO_BLOCK ((u64)~0)
@@ -1519,7 +1520,7 @@ int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n)
 	spin_lock(&sdp->sd_rindex_spin);
 	rgd->rd_free_clone -= *n;
 	spin_unlock(&sdp->sd_rindex_spin);
-
+	trace_gfs2_block_alloc(ip, block, *n, GFS2_BLKST_USED);
 	*bn = block;
 	return 0;
 
@@ -1571,7 +1572,7 @@ u64 gfs2_alloc_di(struct gfs2_inode *dip, u64 *generation)
 	spin_lock(&sdp->sd_rindex_spin);
 	rgd->rd_free_clone--;
 	spin_unlock(&sdp->sd_rindex_spin);
-
+	trace_gfs2_block_alloc(dip, block, 1, GFS2_BLKST_DINODE);
 	return block;
 }
 
@@ -1591,7 +1592,7 @@ void gfs2_free_data(struct gfs2_inode *ip, u64 bstart, u32 blen)
 	rgd = rgblk_free(sdp, bstart, blen, GFS2_BLKST_FREE);
 	if (!rgd)
 		return;
-
+	trace_gfs2_block_alloc(ip, bstart, blen, GFS2_BLKST_FREE);
 	rgd->rd_free += blen;
 
 	gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
@@ -1619,7 +1620,7 @@ void gfs2_free_meta(struct gfs2_inode *ip, u64 bstart, u32 blen)
 	rgd = rgblk_free(sdp, bstart, blen, GFS2_BLKST_FREE);
 	if (!rgd)
 		return;
-
+	trace_gfs2_block_alloc(ip, bstart, blen, GFS2_BLKST_FREE);
 	rgd->rd_free += blen;
 
 	gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
@@ -1642,6 +1643,7 @@ void gfs2_unlink_di(struct inode *inode)
 	rgd = rgblk_free(sdp, blkno, 1, GFS2_BLKST_UNLINKED);
 	if (!rgd)
 		return;
+	trace_gfs2_block_alloc(ip, blkno, 1, GFS2_BLKST_UNLINKED);
 	gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
 	gfs2_rgrp_out(rgd, rgd->rd_bits[0].bi_bh->b_data);
 	gfs2_trans_add_rg(rgd);
@@ -1673,6 +1675,7 @@ static void gfs2_free_uninit_di(struct gfs2_rgrpd *rgd, u64 blkno)
 void gfs2_free_di(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip)
 {
 	gfs2_free_uninit_di(rgd, ip->i_no_addr);
+	trace_gfs2_block_alloc(ip, ip->i_no_addr, 1, GFS2_BLKST_FREE);
 	gfs2_quota_change(ip, -1, ip->i_inode.i_uid, ip->i_inode.i_gid);
 	gfs2_meta_wipe(ip, ip->i_no_addr, 1);
 }