NFS: Replace dprintk callsites in nfs_readpage(s)

These new events report slightly different information for readpage
and readpages/readahead.

For readpage:
             fsx-1387  [006]   380.761896: nfs_aop_readpage:    fileid=00:28:2 fhandle=0x36fbbe51 version=1752899355910932437 offset=131072
             fsx-1387  [006]   380.761900: nfs_aop_readpage_done: fileid=00:28:2 fhandle=0x36fbbe51 version=1752899355910932437 offset=131072 ret=0

The index of a synchronous single-page read is reported.

For readpages:

             fsx-1387  [006]   380.760847: nfs_aop_readahead:   fileid=00:28:2 fhandle=0x36fbbe51 version=1752899355909932456 nr_pages=3
             fsx-1387  [006]   380.760853: nfs_aop_readahead_done: fileid=00:28:2 fhandle=0x36fbbe51 version=1752899355909932456 nr_pages=3 ret=0

The count of pages requested is reported. nfs_readpages does not
wait for the READ requests to complete.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfstrace.h

@@ -862,6 +862,152 @@ TRACE_EVENT(nfs_sillyrename_unlink,
 		)
 );
 
+TRACE_EVENT(nfs_aop_readpage,
+		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(u64, version)
+			__field(loff_t, offset)
+		),
+
+		TP_fast_assign(
+			const struct nfs_inode *nfsi = NFS_I(inode);
+
+			__entry->dev = inode->i_sb->s_dev;
+			__entry->fileid = nfsi->fileid;
+			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);
+			__entry->version = inode_peek_iversion_raw(inode);
+			__entry->offset = page_index(page) << PAGE_SHIFT;
+		),
+
+		TP_printk(
+			"fileid=%02x:%02x:%llu fhandle=0x%08x version=%llu offset=%lld",
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->fileid,
+			__entry->fhandle, __entry->version,
+			__entry->offset
+		)
+);
+
+TRACE_EVENT(nfs_aop_readpage_done,
+		TP_PROTO(
+			const struct inode *inode,
+			struct page *page,
+			int ret
+		),
+
+		TP_ARGS(inode, page, ret),
+
+		TP_STRUCT__entry(
+			__field(dev_t, dev)
+			__field(u32, fhandle)
+			__field(int, ret)
+			__field(u64, fileid)
+			__field(u64, version)
+			__field(loff_t, offset)
+		),
+
+		TP_fast_assign(
+			const struct nfs_inode *nfsi = NFS_I(inode);
+
+			__entry->dev = inode->i_sb->s_dev;
+			__entry->fileid = nfsi->fileid;
+			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);
+			__entry->version = inode_peek_iversion_raw(inode);
+			__entry->offset = page_index(page) << PAGE_SHIFT;
+			__entry->ret = ret;
+		),
+
+		TP_printk(
+			"fileid=%02x:%02x:%llu fhandle=0x%08x version=%llu offset=%lld ret=%d",
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->fileid,
+			__entry->fhandle, __entry->version,
+			__entry->offset, __entry->ret
+		)
+);
+
+TRACE_EVENT(nfs_aop_readahead,
+		TP_PROTO(
+			const struct inode *inode,
+			unsigned int nr_pages
+		),
+
+		TP_ARGS(inode, nr_pages),
+
+		TP_STRUCT__entry(
+			__field(dev_t, dev)
+			__field(u32, fhandle)
+			__field(u64, fileid)
+			__field(u64, version)
+			__field(unsigned int, nr_pages)
+		),
+
+		TP_fast_assign(
+			const struct nfs_inode *nfsi = NFS_I(inode);
+
+			__entry->dev = inode->i_sb->s_dev;
+			__entry->fileid = nfsi->fileid;
+			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);
+			__entry->version = inode_peek_iversion_raw(inode);
+			__entry->nr_pages = nr_pages;
+		),
+
+		TP_printk(
+			"fileid=%02x:%02x:%llu fhandle=0x%08x version=%llu nr_pages=%u",
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->fileid,
+			__entry->fhandle, __entry->version,
+			__entry->nr_pages
+		)
+);
+
+TRACE_EVENT(nfs_aop_readahead_done,
+		TP_PROTO(
+			const struct inode *inode,
+			unsigned int nr_pages,
+			int ret
+		),
+
+		TP_ARGS(inode, nr_pages, ret),
+
+		TP_STRUCT__entry(
+			__field(dev_t, dev)
+			__field(u32, fhandle)
+			__field(int, ret)
+			__field(u64, fileid)
+			__field(u64, version)
+			__field(unsigned int, nr_pages)
+		),
+
+		TP_fast_assign(
+			const struct nfs_inode *nfsi = NFS_I(inode);
+
+			__entry->dev = inode->i_sb->s_dev;
+			__entry->fileid = nfsi->fileid;
+			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);
+			__entry->version = inode_peek_iversion_raw(inode);
+			__entry->nr_pages = nr_pages;
+			__entry->ret = ret;
+		),
+
+		TP_printk(
+			"fileid=%02x:%02x:%llu fhandle=0x%08x version=%llu nr_pages=%u ret=%d",
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->fileid,
+			__entry->fhandle, __entry->version,
+			__entry->nr_pages, __entry->ret
+		)
+);
+
 TRACE_EVENT(nfs_initiate_read,
 		TP_PROTO(
 			const struct nfs_pgio_header *hdr

fs/nfs/read.c

@@ -337,8 +337,7 @@ int nfs_readpage(struct file *file, struct page *page)
 	struct inode *inode = page_file_mapping(page)->host;
 	int ret;
 
-	dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
-		page, PAGE_SIZE, page_index(page));
+	trace_nfs_aop_readpage(inode, page);
 	nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
 
 	/*
@@ -390,9 +389,11 @@ int nfs_readpage(struct file *file, struct page *page)
 	}
 out:
 	put_nfs_open_context(desc.ctx);
+	trace_nfs_aop_readpage_done(inode, page, ret);
 	return ret;
 out_unlock:
 	unlock_page(page);
+	trace_nfs_aop_readpage_done(inode, page, ret);
 	return ret;
 }
 
@@ -403,10 +404,7 @@ int nfs_readpages(struct file *file, struct address_space *mapping,
 	struct inode *inode = mapping->host;
 	int ret;
 
-	dprintk("NFS: nfs_readpages (%s/%Lu %d)\n",
-			inode->i_sb->s_id,
-			(unsigned long long)NFS_FILEID(inode),
-			nr_pages);
+	trace_nfs_aop_readahead(inode, nr_pages);
 	nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
 
 	ret = -ESTALE;
@@ -439,6 +437,7 @@ int nfs_readpages(struct file *file, struct address_space *mapping,
 read_complete:
 	put_nfs_open_context(desc.ctx);
 out:
+	trace_nfs_aop_readahead_done(inode, nr_pages, ret);
 	return ret;
 }