xfs: add writable tracepoint for xfs file buffer read

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I3UHF8
CVE: NA

-------------------------------------------------

This patch adds a new struct xfs_writable_file into file
uapi/include/linux/xfs.h and adds a tracepoint that can modify
struct xfs_writable_file. Then we can set file->f_mode in ebpf
program to control the file.
Signed-off-by: NYufen Yu <yuyufen@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/xfs/xfs_file.c

@@ -232,10 +232,21 @@ xfs_file_buffered_aio_read(
 	struct kiocb		*iocb,
 	struct iov_iter		*to)
 {
-	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
+	struct file		*filp = iocb->ki_filp;
+	struct xfs_inode	*ip = XFS_I(file_inode(filp));
 	ssize_t			ret;
+	struct xfs_writable_file file;
+
+	file.name = file_dentry(filp)->d_name.name;
+	file.f_mode = 0;
+	file.i_size = file_inode(filp)->i_size;
+	file.prev_pos = filp->f_ra.prev_pos;
 
 	trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);
+	trace_xfs_file_read(&file, ip, iov_iter_count(to), iocb->ki_pos);
+
+	if (file.f_mode)
+		filp->f_mode |= file.f_mode;
 
 	if (iocb->ki_flags & IOCB_NOWAIT) {
 		if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED))

fs/xfs/xfs_linux.h

@@ -60,6 +60,7 @@ typedef __u32			xfs_nlink_t;
 #include <linux/list_sort.h>
 #include <linux/ratelimit.h>
 #include <linux/rhashtable.h>
+#include <uapi/linux/xfs.h>
 
 #include <asm/page.h>
 #include <asm/div64.h>

fs/xfs/xfs_trace.h

@@ -3371,6 +3371,52 @@ TRACE_EVENT(xfs_iunlink_update_bucket,
 		  __entry->new_ptr)
 );
 
+DECLARE_EVENT_CLASS(xfs_file_read,
+		TP_PROTO(struct xfs_writable_file *file, struct xfs_inode *ip,
+			size_t count, loff_t offset),
+		TP_ARGS(file, ip, count, offset),
+		TP_STRUCT__entry(
+			__field(struct xfs_writable_file *, file)
+			__field(dev_t, dev)
+			__field(xfs_ino_t, ino)
+			__field(loff_t, offset)
+			__field(size_t, count)
+		),
+		TP_fast_assign(
+			__entry->file = 0;
+			__entry->dev = VFS_I(ip)->i_sb->s_dev;
+			__entry->ino = ip->i_ino;
+			__entry->offset = offset;
+			__entry->count = count;
+		),
+		TP_printk("dev %d:%d ino 0x%llx offset 0x%llx count 0x%zx",
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			__entry->ino,
+			__entry->offset,
+			__entry->count)
+);
+
+#ifdef DEFINE_EVENT_WRITABLE
+#undef XFS_DEFINE_EVENT
+#define XFS_DEFINE_EVENT(template, call, proto, args, size)		\
+	DEFINE_EVENT_WRITABLE(template, call, PARAMS(proto),		\
+			      PARAMS(args), size)
+#else
+#undef XFS_DEFINE_EVENT
+#define XFS_DEFINE_EVENT(template, call, proto, args, size)		\
+	DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args))
+#endif
+
+XFS_DEFINE_EVENT(xfs_file_read, xfs_file_read,
+
+		TP_PROTO(struct xfs_writable_file *file, struct xfs_inode *ip,
+			size_t count, loff_t offset),
+
+		TP_ARGS(file, ip, count, offset),
+
+		sizeof(struct xfs_writable_file)
+);
+
 #endif /* _TRACE_XFS_H */
 
 #undef TRACE_INCLUDE_PATH

include/uapi/linux/xfs.h

+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+
+#ifndef _UAPI_LINUX_XFS_H
+#define _UAPI_LINUX_XFS_H
+
+#include <linux/types.h>
+
+struct xfs_writable_file {
+	const unsigned char *name;
+	unsigned int f_mode; /* can be set into file->f_mode */
+	long long i_size; /* file size */
+	long long prev_pos;  /* ra->prev_pos */
+};
+
+#endif /* _UAPI_LINUX_XFS_H */