bcachefs: Improved errcodes

Instead of overloading standard error codes (EINTR/EAGAIN), and defining
short lists of error codes in multiple places that potentially end up
overlapping & conflicting, we're now going to have one master list of
error codes.

Error codes are defined with an x-macro: thus we also have
bch2_err_str() now.

Also, error codes have a class field. Now, instead of checking for
errors with ==, code should use bch2_err_matches(), which returns true
if the error is equal to or a sub-error of the error class.

This means we can define unique errors for every source location where
an error is generated, which will help improve our error messages.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 27 insertions, 6 deletions

diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
index 0581f3c7a0d8..69cc7cdd1c06 100644
--- a/fs/bcachefs/errcode.h
+++ b/fs/bcachefs/errcode.h
@@ -2,12 +2,33 @@
 #ifndef _BCACHEFS_ERRCODE_H
 #define _BCACHEFS_ERRCODE_H
 
-enum {
-	/* Bucket allocator: */
-	OPEN_BUCKETS_EMPTY =	2048,
-	FREELIST_EMPTY,		/* Allocator thread not keeping up */
-	INSUFFICIENT_DEVICES,
-	NEED_SNAPSHOT_CLEANUP,
+#define BCH_ERRCODES()							\
+	x(0,			open_buckets_empty)			\
+	x(0,			freelist_empty)				\
+	x(freelist_empty,	no_buckets_found)			\
+	x(0,			insufficient_devices)			\
+	x(0,			need_snapshot_cleanup)
+
+enum bch_errcode {
+	BCH_ERR_START		= 2048,
+#define x(class, err) BCH_ERR_##err,
+	BCH_ERRCODES()
+#undef x
+	BCH_ERR_MAX
 };
 
+const char *bch2_err_str(int);
+bool __bch2_err_matches(int, int);
+
+static inline bool _bch2_err_matches(int err, int class)
+{
+	return err && __bch2_err_matches(err, class);
+}
+
+#define bch2_err_matches(_err, _class)			\
+({							\
+	BUILD_BUG_ON(!__builtin_constant_p(_class));	\
+	_bch2_err_matches(_err, _class);		\
+})
+
 #endif /* _BCACHFES_ERRCODE_H */