Hi all, This is a couple small error handling fixes for ->iomap_end() errors (via iomap_iter()). The immediate problem here was that the ->iomap_end() error return started overriding an iter.status error code, which on ext4 happened to trigger dio fallback to buffered I/O in some cases. Jan has actually fixed that separately in ext4 [1], but I wanted to take an independent look at iomap to see if it is worth fixing as well. The more I poked around the more it seemed like it's more appropriate to return the initial error code in iter.status if one is pending. I also eventually noticed the DAX vs. reflink case documented in patch 2, which further tweaks the error handling and supports the former reasoning. These are separate patches because they are separate issues. This has survived my testing since the RFC was posted and some Reviewed-by's have trickled in, so there are no real changes for v1 other than adding those tags. Thoughts, reviews, flames appreciated. Brian [1] https://lore.kernel.org/linux-ext4/20250901112739.32484-2-jack@xxxxxxx/ v1: - Added R-b tags. rfc: https://lore.kernel.org/linux-fsdevel/20250902150755.289469-1-bfoster@xxxxxxxxxx/ Brian Foster (2): iomap: prioritize iter.status error over ->iomap_end() iomap: revert the iomap_iter pos on ->iomap_end() error fs/iomap/iter.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) -- 2.51.0
