f2fs: support to trace f2fs_bmap()

to show f2fs_bmap()'s result as below:

f2fs_bmap: dev = (251,0), ino = 7, lblock:0, pblock:396800
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -3713,18 +3713,26 @@ static sector_t f2fs_bmap_compress(struct inode *inode, sector_t block)
 static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
 {
 	struct inode *inode = mapping->host;
+	struct buffer_head tmp = {
+		.b_size = i_blocksize(inode),
+	};
+	sector_t blknr = 0;
 
 	if (f2fs_has_inline_data(inode))
-		return 0;
+		goto out;
 
 	/* make sure allocating whole blocks */
 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
 		filemap_write_and_wait(mapping);
 
 	if (f2fs_compressed_file(inode))
-		return f2fs_bmap_compress(inode, block);
+		blknr = f2fs_bmap_compress(inode, block);
 
-	return generic_block_bmap(mapping, block, get_data_block_bmap);
+	if (!get_data_block_bmap(inode, block, &tmp, 0))
+		blknr = tmp.b_blocknr;
+out:
+	trace_f2fs_bmap(inode, block, blknr);
+	return blknr;
 }
 
 #ifdef CONFIG_MIGRATION

include/trace/events/f2fs.h

@@ -1891,6 +1891,32 @@ TRACE_EVENT(f2fs_iostat,
 		__entry->fs_cdrio, __entry->fs_nrio, __entry->fs_mrio)
 );
 
+TRACE_EVENT(f2fs_bmap,
+
+	TP_PROTO(struct inode *inode, sector_t lblock, sector_t pblock),
+
+	TP_ARGS(inode, lblock, pblock),
+
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(ino_t, ino)
+		__field(sector_t, lblock)
+		__field(sector_t, pblock)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= inode->i_sb->s_dev;
+		__entry->ino		= inode->i_ino;
+		__entry->lblock		= lblock;
+		__entry->pblock		= pblock;
+	),
+
+	TP_printk("dev = (%d,%d), ino = %lu, lblock:%lld, pblock:%lld",
+		show_dev_ino(__entry),
+		(unsigned long long)__entry->lblock,
+		(unsigned long long)__entry->pblock)
+);
+
 #endif /* _TRACE_F2FS_H */
 
  /* This part must be outside protection */