GFS2: Improve block reservation tracing

This patch improves the tracing of block reservations by
removing some corner cases and also providing more useful
detail in the traces.

A new field is added to the reservation structure to contain
the inode number. This is used since in certain contexts it is
not possible to access the inode itself to obtain this information.
As a result we can then display the inode number for all tracepoints
and also in case we dump the resource group.

The "del" tracepoint operation has been removed. This could be called
with the reservation rgrp set to NULL. That resulted in not printing
the device number, and thus making the information largely useless
anyway. Also, the conditional on the rgrp being NULL can then be
removed from the tracepoint. After this change, all the block
reservation tracepoint calls will be called with the rgrp information.

The existing ins,clm and tdel calls to the block reservation tracepoint
are sufficient to track the entire life of the block reservation.

In gfs2_block_alloc() the error detection is updated to print out
the inode number of the problematic inode. This can then be compared
against the information in the glock dump,tracepoints, etc.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 30c864e..87ee0b7 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -448,10 +448,11 @@ int gfs2_rs_alloc(struct gfs2_inode *ip)
 	return error;
 }
 
-static void dump_rs(struct seq_file *seq, struct gfs2_blkreserv *rs)
+static void dump_rs(struct seq_file *seq, const struct gfs2_blkreserv *rs)
 {
-	gfs2_print_dbg(seq, "  r: %llu s:%llu b:%u f:%u\n",
-		       rs->rs_rbm.rgd->rd_addr, gfs2_rbm_to_block(&rs->rs_rbm),
+	gfs2_print_dbg(seq, "  B: n:%llu s:%llu b:%u f:%u\n",
+		       (unsigned long long)rs->rs_inum,
+		       (unsigned long long)gfs2_rbm_to_block(&rs->rs_rbm),
 		       rs->rs_rbm.offset, rs->rs_free);
 }
 
@@ -468,7 +469,7 @@ static void __rs_deltree(struct gfs2_inode *ip, struct gfs2_blkreserv *rs)
 		return;
 
 	rgd = rs->rs_rbm.rgd;
-	trace_gfs2_rs(ip, rs, TRACE_RS_TREEDEL);
+	trace_gfs2_rs(rs, TRACE_RS_TREEDEL);
 	rb_erase(&rs->rs_node, &rgd->rd_rstree);
 	RB_CLEAR_NODE(&rs->rs_node);
 	BUG_ON(!rgd->rd_rs_cnt);
@@ -511,7 +512,6 @@ void gfs2_rs_delete(struct gfs2_inode *ip)
 	down_write(&ip->i_rw_mutex);
 	if (ip->i_res) {
 		gfs2_rs_deltree(ip, ip->i_res);
-		trace_gfs2_rs(ip, ip->i_res, TRACE_RS_DELETE);
 		BUG_ON(ip->i_res->rs_free);
 		kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
 		ip->i_res = NULL;
@@ -1253,6 +1253,7 @@ static struct gfs2_blkreserv *rs_insert(struct gfs2_bitmap *bi,
 	rs->rs_free = amount;
 	rs->rs_rbm.offset = biblk;
 	rs->rs_rbm.bi = bi;
+	rs->rs_inum = ip->i_no_addr;
 	rb_link_node(&rs->rs_node, parent, newn);
 	rb_insert_color(&rs->rs_node, &rgd->rd_rstree);
 
@@ -1260,7 +1261,7 @@ static struct gfs2_blkreserv *rs_insert(struct gfs2_bitmap *bi,
 	rgd->rd_reserved += amount; /* blocks reserved */
 	rgd->rd_rs_cnt++; /* number of in-tree reservations */
 	spin_unlock(&rgd->rd_rsspin);
-	trace_gfs2_rs(ip, rs, TRACE_RS_INSERT);
+	trace_gfs2_rs(rs, TRACE_RS_INSERT);
 	return rs;
 }
 
@@ -1966,7 +1967,7 @@ static void gfs2_adjust_reservation(struct gfs2_inode *ip,
 			rlen = min(rs->rs_free, len);
 			rs->rs_free -= rlen;
 			rgd->rd_reserved -= rlen;
-			trace_gfs2_rs(ip, rs, TRACE_RS_CLAIM);
+			trace_gfs2_rs(rs, TRACE_RS_CLAIM);
 			if (rs->rs_free && !ret)
 				goto out;
 		}
@@ -2005,10 +2006,6 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
 	else
 		goal = rbm.rgd->rd_last_alloc + rbm.rgd->rd_data0;
 
-	if ((goal < rbm.rgd->rd_data0) ||
-	    (goal >= rbm.rgd->rd_data0 + rbm.rgd->rd_data))
-		rbm.rgd = gfs2_blk2rgrpd(sdp, goal, 1);
-
 	gfs2_rbm_from_block(&rbm, goal);
 	error = gfs2_rbm_find(&rbm, GFS2_BLKST_FREE, ip, false);
 
@@ -2019,7 +2016,8 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
 
 	/* Since all blocks are reserved in advance, this shouldn't happen */
 	if (error) {
-		fs_warn(sdp, "error=%d, nblocks=%u, full=%d\n", error, *nblocks,
+		fs_warn(sdp, "inum=%llu error=%d, nblocks=%u, full=%d\n",
+			(unsigned long long)ip->i_no_addr, error, *nblocks,
 			test_bit(GBF_FULL, &rbm.rgd->rd_bits->bi_flags));
 		goto rgrp_error;
 	}