ext4: Add markers for better debuggability

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 05d9f81..918aec0 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2878,8 +2878,9 @@
 		discard_block = (ext4_fsblk_t) entry->group * EXT4_BLOCKS_PER_GROUP(sb)
 			+ entry->start_blk
 			+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
-		trace_mark(ext4_discard_blocks, "dev %s blk %llu count %u", sb->s_id,
-			   (unsigned long long) discard_block, entry->count);
+		trace_mark(ext4_discard_blocks, "dev %s blk %llu count %u",
+			   sb->s_id, (unsigned long long) discard_block,
+			   entry->count);
 		sb_issue_discard(sb, discard_block, entry->count);
 
 		kmem_cache_free(ext4_free_ext_cachep, entry);
@@ -3697,6 +3698,10 @@
 
 	mb_debug("new inode pa %p: %llu/%u for %u\n", pa,
 			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
+	trace_mark(ext4_mb_new_inode_pa,
+		   "dev %s ino %lu pstart %llu len %u lstart %u",
+		   sb->s_id, ac->ac_inode->i_ino,
+		   pa->pa_pstart, pa->pa_len, pa->pa_lstart);
 
 	ext4_mb_use_inode_pa(ac, pa);
 	atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
@@ -3754,7 +3759,9 @@
 	pa->pa_linear = 1;
 
 	mb_debug("new group pa %p: %llu/%u for %u\n", pa,
-			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
+		 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
+	trace_mark(ext4_mb_new_group_pa, "dev %s pstart %llu len %u lstart %u",
+		   sb->s_id, pa->pa_pstart, pa->pa_len, pa->pa_lstart);
 
 	ext4_mb_use_group_pa(ac, pa);
 	atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
@@ -3807,12 +3814,14 @@
 	unsigned int next;
 	ext4_group_t group;
 	ext4_grpblk_t bit;
+	unsigned long long grp_blk_start;
 	sector_t start;
 	int err = 0;
 	int free = 0;
 
 	BUG_ON(pa->pa_deleted == 0);
 	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
+	grp_blk_start = pa->pa_pstart - bit;
 	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
 	end = bit + pa->pa_len;
 
@@ -3842,6 +3851,10 @@
 			ext4_mb_store_history(ac);
 		}
 
+		trace_mark(ext4_mb_release_inode_pa,
+			   "dev %s ino %lu block %llu count %u",
+			   sb->s_id, pa->pa_inode->i_ino, grp_blk_start + bit,
+			   next - bit);
 		mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
 		bit = next + 1;
 	}
@@ -3875,6 +3888,8 @@
 	if (ac)
 		ac->ac_op = EXT4_MB_HISTORY_DISCARD;
 
+	trace_mark(ext4_mb_release_group_pa, "dev %s pstart %llu len %d",
+		   sb->s_id, pa->pa_pstart, pa->pa_len);
 	BUG_ON(pa->pa_deleted == 0);
 	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
 	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
@@ -4040,6 +4055,8 @@
 	}
 
 	mb_debug("discard preallocation for inode %lu\n", inode->i_ino);
+	trace_mark(ext4_discard_preallocations, "dev %s ino %lu", sb->s_id,
+		   inode->i_ino);
 
 	INIT_LIST_HEAD(&list);
 
@@ -4492,6 +4509,8 @@
 	int ret;
 	int freed = 0;
 
+	trace_mark(ext4_mb_discard_preallocations, "dev %s needed %d",
+		   sb->s_id, needed);
 	for (i = 0; i < EXT4_SB(sb)->s_groups_count && needed > 0; i++) {
 		ret = ext4_mb_discard_group_preallocations(sb, i, needed);
 		freed += ret;
@@ -4520,6 +4539,18 @@
 	sb = ar->inode->i_sb;
 	sbi = EXT4_SB(sb);
 
+	trace_mark(ext4_request_blocks, "dev %s flags %u len %u ino %lu "
+		   "lblk %llu goal %llu lleft %llu lright %llu "
+		   "pleft %llu pright %llu ",
+		   sb->s_id, ar->flags, ar->len,
+		   ar->inode ? ar->inode->i_ino : 0,
+		   (unsigned long long) ar->logical,
+		   (unsigned long long) ar->goal,
+		   (unsigned long long) ar->lleft,
+		   (unsigned long long) ar->lright,
+		   (unsigned long long) ar->pleft,
+		   (unsigned long long) ar->pright);
+
 	if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag) {
 		/*
 		 * With delalloc we already reserved the blocks
@@ -4622,6 +4653,19 @@
 						reserv_blks);
 	}
 
+	trace_mark(ext4_allocate_blocks,
+		   "dev %s block %llu flags %u len %u ino %lu "
+		   "logical %llu goal %llu lleft %llu lright %llu "
+		   "pleft %llu pright %llu ",
+		   sb->s_id, (unsigned long long) block,
+		   ar->flags, ar->len, ar->inode ? ar->inode->i_ino : 0,
+		   (unsigned long long) ar->logical,
+		   (unsigned long long) ar->goal,
+		   (unsigned long long) ar->lleft,
+		   (unsigned long long) ar->lright,
+		   (unsigned long long) ar->pleft,
+		   (unsigned long long) ar->pright);
+
 	return block;
 }
 
@@ -4755,6 +4799,10 @@
 	}
 
 	ext4_debug("freeing block %lu\n", block);
+	trace_mark(ext4_free_blocks,
+		   "dev %s block %llu count %lu metadata %d ino %lu",
+		   sb->s_id, (unsigned long long) block, count, metadata,
+		   inode ? inode->i_ino : 0);
 
 	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
 	if (ac) {