[PATCH 06/38] vfs: Introduce logging functions [ver #10]

David Howells
2018-07-27T17:36:29Z

Introduce a set of logging functions through which informational messages,
warnings and error messages incurred by the mount procedure can be logged
and, in a future patch, passed to userspace instead by way of the
filesystem configuration context file descriptor.

There are four functions:

(1) infof(const char *fmt, ...);

Logs an informational message.

(2) warnf(const char *fmt, ...);

Logs a warning message.

(3) errorf(const char *fmt, ...);

Logs an error message.

(4) invalf(const char *fmt, ...);

As errof(), but returns -EINVAL so can be used on a return statement.

Signed-off-by: David Howells <dhowells@redhat.com>
---

include/linux/fs_context.h | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)

diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 0ff4969f9d5a..a88b54752f86 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -98,4 +98,46 @@ struct fs_context_operations {
int (*get_tree)(struct fs_context *fc);
};

+#define logfc(FC, FMT, ...) pr_notice(FMT, ## __VA_ARGS__)
+
+/**
+ * infof - Store supplementary informational message
+ * @fc: The context in which to log the informational message
+ * @fmt: The format string
+ *
+ * Store the supplementary informational message for the process if the process
+ * has enabled the facility.
+ */
+#define infof(fc, fmt, ...) ({ logfc(fc, fmt, ## __VA_ARGS__); })
+
+/**
+ * warnf - Store supplementary warning message
+ * @fc: The context in which to log the error message
+ * @fmt: The format string
+ *
+ * Store the supplementary warning message for the process if the process has
+ * enabled the facility.
+ */
+#define warnf(fc, fmt, ...) ({ logfc(fc, fmt, ## __VA_ARGS__); })
+
+/**
+ * errorf - Store supplementary error message
+ * @fc: The context in which to log the error message
+ * @fmt: The format string
+ *
+ * Store the supplementary error message for the process if the process has
+ * enabled the facility.
+ */
+#define errorf(fc, fmt, ...) ({ logfc(fc, fmt, ## __VA_ARGS__); })
+
+/**
+ * invalf - Store supplementary invalid argument error message
+ * @fc: The context in which to log the error message
+ * @fmt: The format string
+ *
+ * Store the supplementary error message for the process if the process has
+ * enabled the facility and return -EINVAL.
+ */
+#define invalf(fc, fmt, ...) ({ errorf(fc, fmt, ## __VA_ARGS__); -EINVAL; })
+
#endif /* _LINUX_FS_CONTEXT_H */