On Mon, Feb 15, 2021 at 11:05:33AM +0000, Filipe Manana wrote:
> On Sat, Feb 13, 2021 at 1:07 AM Wang Yugui <wangyu...@e16-tech.com> wrote:
> > > This bug only affects 5.10 kernels, and the regression was introduced in
> > > 5.10-rc1 by commit 0eb79294dbe328 ("btrfs: dio iomap DSYNC workaround").
> > > The bug does not exist in 5.11 kernels due to commit ecfdc08b8cc65d
> > > ("btrfs: remove dio iomap DSYNC workaround"), which depends on other
> > > changes that went into the merge window for 5.11. So this is a fix only
> > > for 5.10.x stable kernels, as there are people hitting this.
> >
> > It is OK too to backport commit ecfdc08b8cc65d
> > ("btrfs: remove dio iomap DSYNC workaround") to 5.10 for this problem?
> >
> > the iomap issue for commit 0eb79294dbe328 ("btrfs: dio iomap DSYNC
> > workaround")
> > is already fixed in 5.10?
>
> Quoting the changelog:
>
> "commit ecfdc08b8cc65d
> ("btrfs: remove dio iomap DSYNC workaround"), which depends on other
> changes that went into the merge window for 5.11."
>
> All the changes, are (at least):
>
> commit ecfdc08b8cc65d737eebc26a1ee1875a097fd6a0 --> 5.11-rc1
> Author: Goldwyn Rodrigues <rgold...@suse.com>
> Date: Thu Sep 24 11:39:21 2020 -0500
>
> btrfs: remove dio iomap DSYNC workaround
>
> commit a42fa643169d2325602572633fcaa16862990e28
> Author: Goldwyn Rodrigues <rgold...@suse.com>
> Date: Thu Sep 24 11:39:20 2020 -0500
>
> btrfs: call iomap_dio_complete() without inode_lock
>
> commit 502756b380938022c848761837f8fa3976906aa1
> Author: Goldwyn Rodrigues <rgold...@suse.com>
> Date: Thu Sep 24 11:39:19 2020 -0500
>
> btrfs: remove btrfs_inode::dio_sem
>
> commit e9adabb9712ef9424cbbeeaa027d962ab5262e19
> Author: Goldwyn Rodrigues <rgold...@suse.com>
> Date: Thu Sep 24 11:39:18 2020 -0500
>
> btrfs: use shared lock for direct writes within EOF
>
> commit c352370633400d13765cc88080c969799ea51108
> Author: Goldwyn Rodrigues <rgold...@suse.com>
> Date: Thu Sep 24 11:39:17 2020 -0500
>
> btrfs: push inode locking and unlocking into buffered/direct write
>
> commit a14b78ad06aba0fa7e76d2bc13c5ba581a7f331a
> Author: Goldwyn Rodrigues <rgold...@suse.com>
> Date: Thu Sep 24 11:39:16 2020 -0500
>
> btrfs: introduce btrfs_inode_lock()/unlock()
>
> commit b8d8e1fd570a194904f545b135efc880d96a41a4
> Author: Goldwyn Rodrigues <rgold...@suse.com>
> Date: Thu Sep 24 11:39:15 2020 -0500
>
> btrfs: introduce btrfs_write_check()
>
> That's probably too much to add to stable at once, plus I'm assuming
> all required iomap dependencies are in 5.10 already (it seems so,
> unless I missed something).
>
> Usually we don't add patches to stable that didn't go through Linus'
> tree either (there were 1 or 2 very rare exceptions in the past I
> think), but when a backport depends on so many patches, and not all
> from the same patchset, the risk of getting something wrong is
> significant. That's why I opted to send this patch, which is much more
> simple.
Agreed, in this case the backport would be too big, just the diffstat
between b8d8e1fd570^..ecfdc08b8cc6 is
5 files changed, 213 insertions(+), 240 deletions(-)
This fix is minimal and suitable for stable as an exception. You did not
CC sta...@vger.kernel.org so you'll need to send it again. Please CC me
too in case there are some questions from stable team. Thanks.
