I've been working on set of patches to clean up how writeback errors are tracked and handled in the kernel:
http://marc.info/?l=linux-fsdevel&m=149304074111261&w=2 The basic idea is that rather than having a set of flags that are cleared whenever they are checked, we have a sequence counter and error that are tracked on a per-mapping basis, and can then use that sequence counter to tell whether the error should be reported. This changes the way that things like filemap_write_and_wait work. Rather than having to ensure that AS_EIO/AS_ENOSPC are not cleared inappropriately (and thus losing errors that should be reported), you can now tell whether there has been a writeback error since a certain point in time, irrespective of whether anyone else is checking for errors. I've been doing some conversions of the existing code to the new scheme, but btrfs has _really_ complicated error handling. I think it could probably be simplified with this new scheme, but I could use some help here. What I think we probably want to do is to sample the error sequence in the mapping at well-defined points in time (probably when starting a transaction?) and then use that to determine whether writeback errors have occurred since then. Is there anyone in the btrfs community who could help me here? Thanks, -- Jeff Layton <jlay...@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
