summaryrefslogtreecommitdiffstats
path: root/Documentation/filesystems/bcachefs
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/filesystems/bcachefs')
-rw-r--r--Documentation/filesystems/bcachefs/errorcodes.rst30
-rw-r--r--Documentation/filesystems/bcachefs/index.rst11
2 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/filesystems/bcachefs/errorcodes.rst b/Documentation/filesystems/bcachefs/errorcodes.rst
new file mode 100644
index 0000000000..2cccaa0ba7
--- /dev/null
+++ b/Documentation/filesystems/bcachefs/errorcodes.rst
@@ -0,0 +1,30 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+bcachefs private error codes
+----------------------------
+
+In bcachefs, as a hard rule we do not throw or directly use standard error
+codes (-EINVAL, -EBUSY, etc.). Instead, we define private error codes as needed
+in fs/bcachefs/errcode.h.
+
+This gives us much better error messages and makes debugging much easier. Any
+direct uses of standard error codes you see in the source code are simply old
+code that has yet to be converted - feel free to clean it up!
+
+Private error codes may subtype another error code, this allows for grouping of
+related errors that should be handled similarly (e.g. transaction restart
+errors), as well as specifying which standard error code should be returned at
+the bcachefs module boundary.
+
+At the module boundary, we use bch2_err_class() to convert to a standard error
+code; this also emits a trace event so that the original error code be
+recovered even if it wasn't logged.
+
+Do not reuse error codes! Generally speaking, a private error code should only
+be thrown in one place. That means that when we see it in a log message we can
+see, unambiguously, exactly which file and line number it was returned from.
+
+Try to give error codes names that are as reasonably descriptive of the error
+as possible. Frequently, the error will be logged at a place far removed from
+where the error was generated; good names for error codes mean much more
+descriptive and useful error messages.
diff --git a/Documentation/filesystems/bcachefs/index.rst b/Documentation/filesystems/bcachefs/index.rst
new file mode 100644
index 0000000000..e2bd61ccd9
--- /dev/null
+++ b/Documentation/filesystems/bcachefs/index.rst
@@ -0,0 +1,11 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================
+bcachefs Documentation
+======================
+
+.. toctree::
+ :maxdepth: 2
+ :numbered:
+
+ errorcodes