On Thu, Apr 16, 2020 at 02:46:10PM -0700, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@xxxxxx>
>
> Hi,
>
> This is version 2 of my series of fixes, cleanups, and improvements to
> direct I/O and read repair. It's preparation for adding read repair to
> my RWF_ENCODED series [1], but it can go in independently.
>
> Patch 1 adds a new bio helper needed for patch 4. Patches 2 and 3 are
> direct I/O error handling fixes. Patch 4 is a buffered read repair fix.
> Patch 5 is a buffered read repair improvement. Patches 6-9 are trivial
> cleanups. Patch 10 converts direct I/O to use refcount_t, which would've
> helped catch the bug fixed by patch 2. Patches 11-14 drastically
> simplify the direct I/O code. Patch 15 unifies buffered and direct I/O
> read repair, which also makes direct I/O repair actually do validation
> for large failed reads instead of rewriting the whole thing.
>
> Overall, this is net about -350 lines of code and actually makes direct
> I/O more functional.
>
> Note that this series causes btrfs/142 to fail. This is a bug in the
> test, as it assumes that direct I/O doesn't do read validation. This is
> fixed by the fstests patch "btrfs/14{2,3}: use dm-dust instead of
> fail_make_request" which I sent up yesterday [2].
>
> Jens and Christoph are cc'd for patches 1 and 4. Instead of looking at
> the bio internals like I did in v1, I added a new
> bio_for_each_bvec_all() helper.
>
> Changes from v1 [3]:
>
> * Added patch 1 with bio_for_each_bvec_all() helper
> * Dropped patch 8 which moved struct definition
> * Fixed performance regression [4] in patch 13 caused by accidentally
> making all direct I/O submission asynchronous
> * Fixed uninitialized assert in patch 12
> * Fixed misplaced assert in btrfs_check_read_dio_bio in patch 13
> * Added reviewed-bys
> * Refactored btrfs_submit_direct() and btrfs_submit_direct_hook() in
> patch 2 (I didn't add Nikolay's reviewed-by to that one because the
> new patch looks fairly different from patch 1 in v1)
> * Rewrapped csum calculations in patch 10 for easier readability
> * Clarified several commit messages and comments
Thanks, I haven't read the changes yet but fstests passed. There are
some conflicts with the dio-iomap patches, all seem to be in the
expected range and solvable.
