NFS: Replace dfprintks with tracepoints in fscache read and write page functions

Most of fscache and other NFS IO paths are now using tracepoints.
Remove the dfprintks in the NFS fscache read/write page functions
and replace with tracepoints at the begin and end of the functions.

Signed-off-by: Dave Wysochanski <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/fscache.c

···
 #include "internal.h"
 #include "iostat.h"
 #include "fscache.h"
+#include "nfstrace.h"
 
 #define NFSDBG_FACILITY		NFSDBG_FSCACHE
 
···
 {
 	int ret;
 
-	dfprintk(FSCACHE,
-		 "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n",
-		 nfs_i_fscache(inode), page, page->index, page->flags, inode);
-
+	trace_nfs_fscache_read_page(inode, page);
 	if (PageChecked(page)) {
-		dfprintk(FSCACHE, "NFS:    readpage_from_fscache: PageChecked\n");
 		ClearPageChecked(page);
-		return 1;
+		ret = 1;
+		goto out;
 	}
 
 	ret = fscache_fallback_read_page(inode, page);
 	if (ret < 0) {
 		nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL);
-		dfprintk(FSCACHE,
-			 "NFS:    readpage_from_fscache failed %d\n", ret);
 		SetPageChecked(page);
-		return ret;
+		goto out;
 	}
 
 	/* Read completed synchronously */
-	dfprintk(FSCACHE, "NFS:    readpage_from_fscache: read successful\n");
 	nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK);
 	SetPageUptodate(page);
-	return 0;
+	ret = 0;
+out:
+	trace_nfs_fscache_read_page_exit(inode, page, ret);
+	return ret;
 }
 
 /*
···
 {
 	int ret;
 
-	dfprintk(FSCACHE,
-		 "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx))\n",
-		 nfs_i_fscache(inode), page, page->index, page->flags);
+	trace_nfs_fscache_write_page(inode, page);
 
 	ret = fscache_fallback_write_page(inode, page, true);
-
-	dfprintk(FSCACHE,
-		 "NFS:     nfs_fscache_write_page: p:%p(i:%lu f:%lx) ret %d\n",
-		 page, page->index, page->flags, ret);
 
 	if (ret != 0) {
 		nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL);
···
 	} else {
 		nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_OK);
 	}
+	trace_nfs_fscache_write_page_exit(inode, page, ret);
 }

fs/nfs/nfstrace.h

···
 		)
 );
 
+DECLARE_EVENT_CLASS(nfs_fscache_page_event,
+		TP_PROTO(
+			const struct inode *inode,
+			struct page *page
+		),
+
+		TP_ARGS(inode, page),
+
+		TP_STRUCT__entry(
+			__field(dev_t, dev)
+			__field(u32, fhandle)
+			__field(u64, fileid)
+			__field(loff_t, offset)
+		),
+
+		TP_fast_assign(
+			const struct nfs_inode *nfsi = NFS_I(inode);
+			const struct nfs_fh *fh = &nfsi->fh;
+
+			__entry->offset = page_index(page) << PAGE_SHIFT;
+			__entry->dev = inode->i_sb->s_dev;
+			__entry->fileid = nfsi->fileid;
+			__entry->fhandle = nfs_fhandle_hash(fh);
+		),
+
+		TP_printk(
+			"fileid=%02x:%02x:%llu fhandle=0x%08x "
+			"offset=%lld",
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->fileid,
+			__entry->fhandle,
+			(long long)__entry->offset
+		)
+);
+DECLARE_EVENT_CLASS(nfs_fscache_page_event_done,
+		TP_PROTO(
+			const struct inode *inode,
+			struct page *page,
+			int error
+		),
+
+		TP_ARGS(inode, page, error),
+
+		TP_STRUCT__entry(
+			__field(int, error)
+			__field(dev_t, dev)
+			__field(u32, fhandle)
+			__field(u64, fileid)
+			__field(loff_t, offset)
+		),
+
+		TP_fast_assign(
+			const struct nfs_inode *nfsi = NFS_I(inode);
+			const struct nfs_fh *fh = &nfsi->fh;
+
+			__entry->offset = page_index(page) << PAGE_SHIFT;
+			__entry->dev = inode->i_sb->s_dev;
+			__entry->fileid = nfsi->fileid;
+			__entry->fhandle = nfs_fhandle_hash(fh);
+			__entry->error = error;
+		),
+
+		TP_printk(
+			"fileid=%02x:%02x:%llu fhandle=0x%08x "
+			"offset=%lld error=%d",
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->fileid,
+			__entry->fhandle,
+			(long long)__entry->offset, __entry->error
+		)
+);
+#define DEFINE_NFS_FSCACHE_PAGE_EVENT(name) \
+	DEFINE_EVENT(nfs_fscache_page_event, name, \
+			TP_PROTO( \
+				const struct inode *inode, \
+				struct page *page \
+			), \
+			TP_ARGS(inode, page))
+#define DEFINE_NFS_FSCACHE_PAGE_EVENT_DONE(name) \
+	DEFINE_EVENT(nfs_fscache_page_event_done, name, \
+			TP_PROTO( \
+				const struct inode *inode, \
+				struct page *page, \
+				int error \
+			), \
+			TP_ARGS(inode, page, error))
+DEFINE_NFS_FSCACHE_PAGE_EVENT(nfs_fscache_read_page);
+DEFINE_NFS_FSCACHE_PAGE_EVENT_DONE(nfs_fscache_read_page_exit);
+DEFINE_NFS_FSCACHE_PAGE_EVENT(nfs_fscache_write_page);
+DEFINE_NFS_FSCACHE_PAGE_EVENT_DONE(nfs_fscache_write_page_exit);
+
 TRACE_EVENT(nfs_pgio_error,
 	TP_PROTO(
 		const struct nfs_pgio_header *hdr,