On Thu, Mar 12, 2020 at 8:33 PM David Sterba <dsterba@xxxxxxx> wrote:
>
> On Mon, Mar 09, 2020 at 12:41:04PM +0000, fdmanana@xxxxxxxxxx wrote:
> > From: Filipe Manana <fdmanana@xxxxxxxx>
> >
> > This patchset fixes a bug when not using NO_HOLES and makes ranged fsyncs
> > respect the given file range when using the NO_HOLES feature.
> >
> > The bug is about missing file extents items representing a hole after doing
> > a ranged fsync on a file and replaying the log.
> >
> > Btrfs doesn't respect the given range for a fsync when the inode's has the
> > "need full sync" bit set - it treats the fsync as a full ranged one, operating
> > on the whole file, doing more IO and cpu work then needed.
> >
> > That behaviour was needed to fix a corruption bug. Commit 0c713cbab6200b
> > ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges")
> > fixed that bug by turning the ranged fsync into a full ranged one.
> >
> > Later the hole detection code of fsync was simplified a lot in order to
> > fix another bug when using the NO_HOLES feature - done by commit
> > 0e56315ca147b3 ("Btrfs: fix missing hole after hole punching and fsync when
> > using NO_HOLES"). That commit now makes it easy to avoid turning the ranged
> > fsyncs into non-ranged fsyncs.
> >
> > This patchset does those two changes. The first patch fixes the bug mentioned
> > before, patches 2 and 3 are preparation cleanups for patch 4, which is the
> > one that makes fsync respect the given file range when using NO_HOLES.
> >
> > V3: Updated patch one so that the ranged is set to full before locking the
> > inode. To make sure we do writeback and wait for ordered extent
> > completion as much as possible before locking the inode.
> > Remaining patches are unchanged.
> >
> > V2: Added one more patch to the series, which is the first patch, that
> > fixes the bug regarding missing holes after doing a ranged fsync.
> >
> > The remaining patches remain the same, only patch 4 had a trivial
> > conflict when rebasing against patch 1 and got its changelog
> > updated. Now all fstests pass with version 2 of this patchset.
> >
> > Filipe Manana (4):
> > Btrfs: fix missing file extent item for hole after ranged fsync
> > Btrfs: add helper to get the end offset of a file extent item
> > Btrfs: factor out inode items copy loop from btrfs_log_inode()
> > Btrfs: make ranged full fsyncs more efficient
>
> Moved from for-next to misc-next, thanks.
Btw, Josef's reviewed-by tag is missing in the changelog of patch 4
(however there's an unusual reviewed-by tag from you).
Thanks.
