dax: add tracepoints to dax_writeback_mapping_range()

Add tracepoints to dax_writeback_mapping_range(), following the same
logging conventions as the rest of DAX.

Here is an example writeback call:

  msync-1085  [006] ....
   200.902565: dax_writeback_range: dev 259:0 ino 0x1003 pgoff 0x200-0x2ff

  msync-1085  [006] ....
   200.902579: dax_writeback_range_done: dev 259:0 ino 0x1003 pgoff 0x200-0x2ff

[ross.zwisler@linux.intel.com: fix regression in dax_writeback_mapping_range()]
Link: http://lkml.kernel.org/r/20170314215358.31451-1-ross.zwisler@linux.intel.com
Link: http://lkml.kernel.org/r/20170221195116.13278-5-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/dax.c b/fs/dax.c
index 36fafff2e82fa54aa87e8304bcd6e6c17e42fe56..7cf2686761e2d2ae6e2ff94385b61d08f0ec0ba2 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -863,6 +863,8 @@ int dax_writeback_mapping_range(struct address_space *mapping,
        start_index = wbc->range_start >> PAGE_SHIFT;
        end_index = wbc->range_end >> PAGE_SHIFT;
 
+       trace_dax_writeback_range(inode, start_index, end_index);
+
        tag_pages_for_writeback(mapping, start_index, end_index);
 
        pagevec_init(&pvec, 0);
@@ -882,14 +884,14 @@ int dax_writeback_mapping_range(struct address_space *mapping,
 
                        ret = dax_writeback_one(bdev, dax_dev, mapping,
                                        indices[i], pvec.pages[i]);
-                       if (ret < 0) {
-                               put_dax(dax_dev);
-                               return ret;
-                       }
+                       if (ret < 0)
+                               goto out;
                }
        }
+out:
        put_dax(dax_dev);
-       return 0;
+       trace_dax_writeback_range_done(inode, start_index, end_index);
+       return (ret < 0 ? ret : 0);
 }
 EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
 

diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index 2f15dfea7fb17d8e2ce5368e1372de5d6741ccdd..9afe8c8f0beff7b59fe9c8f738572101375a3e82 100644 (file)
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -194,6 +194,38 @@ DEFINE_PTE_FAULT_EVENT(dax_pfn_mkwrite_no_entry);
 DEFINE_PTE_FAULT_EVENT(dax_pfn_mkwrite);
 DEFINE_PTE_FAULT_EVENT(dax_load_hole);
 
+DECLARE_EVENT_CLASS(dax_writeback_range_class,
+       TP_PROTO(struct inode *inode, pgoff_t start_index, pgoff_t end_index),
+       TP_ARGS(inode, start_index, end_index),
+       TP_STRUCT__entry(
+               __field(unsigned long, ino)
+               __field(pgoff_t, start_index)
+               __field(pgoff_t, end_index)
+               __field(dev_t, dev)
+       ),
+       TP_fast_assign(
+               __entry->dev = inode->i_sb->s_dev;
+               __entry->ino = inode->i_ino;
+               __entry->start_index = start_index;
+               __entry->end_index = end_index;
+       ),
+       TP_printk("dev %d:%d ino %#lx pgoff %#lx-%#lx",
+               MAJOR(__entry->dev),
+               MINOR(__entry->dev),
+               __entry->ino,
+               __entry->start_index,
+               __entry->end_index
+       )
+)
+
+#define DEFINE_WRITEBACK_RANGE_EVENT(name) \
+DEFINE_EVENT(dax_writeback_range_class, name, \
+       TP_PROTO(struct inode *inode, pgoff_t start_index, pgoff_t end_index),\
+       TP_ARGS(inode, start_index, end_index))
+
+DEFINE_WRITEBACK_RANGE_EVENT(dax_writeback_range);
+DEFINE_WRITEBACK_RANGE_EVENT(dax_writeback_range_done);
+
 #endif /* _TRACE_FS_DAX_H */
 
 /* This part must be outside protection */