| .. 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. |
