On Sat, Feb 13, 2021 at 1:07 AM Wang Yugui <wangyu...@e16-tech.com> wrote:
>
> Hi,
>
> > 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.
David has more experience on that and it's up to him to decide.
>
> Best Regards
> Wang Yugui (wangyu...@e16-tech.com)
> 2021/02/13
>
>
> > Fixes: 0eb79294dbe328 ("btrfs: dio iomap DSYNC workaround")
> > CC: sta...@vger.kernel.org # 5.10 (and only 5.10)
> > Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1181605
> > Signed-off-by: Filipe Manana <fdman...@suse.com>
> > ---
> > fs/btrfs/inode.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> > index acc47e2ffb46..b536d21541a9 100644
> > --- a/fs/btrfs/inode.c
> > +++ b/fs/btrfs/inode.c
> > @@ -8026,8 +8026,12 @@ ssize_t btrfs_direct_IO(struct kiocb *iocb, struct
> > iov_iter *iter)
> > bool relock = false;
> > ssize_t ret;
> >
> > - if (check_direct_IO(fs_info, iter, offset))
> > + if (check_direct_IO(fs_info, iter, offset)) {
> > + ASSERT(current->journal_info == NULL ||
> > + current->journal_info == BTRFS_DIO_SYNC_STUB);
> > + current->journal_info = NULL;
> > return 0;
> > + }
> >
> > count = iov_iter_count(iter);
> > if (iov_iter_rw(iter) == WRITE) {
> > --
> > 2.28.0
>
>
