On 2019/09/04 7:16, Darrick J. Wong wrote: > On Tue, Sep 03, 2019 at 03:03:25PM +0200, Christoph Hellwig wrote: >> Hi all, >> >> this series contains two updates to the end_io handling for the iomap >> direct I/O code. The first patch is from Matthew and passes the size and >> error separately, and has been taken from his series to convert ext4 to >> use iomap for direct I/O. The second one moves the end_io handler into a >> separate ops structure. This should help with Goldwyns series to use the >> iomap code in btrfs, but as-is already ensures that we don't store a >> function pointer in a mutable data structure. > > The biggest problem with merging these patches (and while we're at it, > Goldwyn's patch adding a srcmap parameter to ->iomap_begin) for 5.4 is > that they'll break whatever Andreas and Damien have been preparing for > gfs2 and zonefs (respectively) based off the iomap-writeback work branch > that I created off of 5.3-rc2 a month ago. > > Digging through the gfs2 and zonefs code, it doesn't look like it would > be difficult to adapt them to the changes, but forcing a rebase at this > point would (a) poke holes in the idea of creating stable work branches > and (b) shoot holes in all the regression testing they've done so far. > I do not have the hardware to test either in detail. For zonefs, the changes are not that big (thanks for sending them :)) and testing does not take long given the lower amount of functionalities compared to a regular FS. So regression testing with changes to iomap will not be a huge problem for me. I can do it if needed. > So the question is: Are all three (xfs/gfs2/zonefs?) downstream users of > iomap ok with a rebase a week and a half before the 5.4 merge window > opens? I'm still inclined to push all these patches (iomap cow and the > directio improvements) into a work branch for 5.5, but if someone wants > this for 5.4 badly enough to persuade everyone else to start their > testing again, then I could see trying to make this happen (no later > than 5pm Pacific on Thursday). Bear in mind I'm on vacation starting > Friday and going until the 15th... No strong opinion either way. I will adjust to what you decide. > > Once iomap accumulates more users (ext4, btrfs) then this sort of thing > will never scale and will likely never happen again. > > Thoughts? Flames? :) > > --D > -- Damien Le Moal Western Digital Research
