On Tue, Jul 4, 2017 at 9:02 PM, Goldwyn Rodrigues <rgoldwyn@xxxxxxx> wrote: > From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx> > > Assigning pos for usage early messes up in append mode, where > the pos is re-assigned in generic_write_checks(). Re-assign > pos to get the correct position to write from iocb->ki_pos. > > Fixes: edf064e7c6fe ("btrfs: nowait aio support") > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx> > Tested-by: Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx> > --- > fs/btrfs/file.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 59e2dccdf75b..7947781229e5 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -1931,6 +1931,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, > */ > update_time_for_write(inode); > > + pos = iocb->ki_pos; > start_pos = round_down(pos, fs_info->sectorsize); > oldsize = i_size_read(inode); > if (start_pos > oldsize) { > -- > 2.12.0 For an append, shouldn't you also be using this updated pos from generic_write_checks when calling check_can_nocow at the top of the function? Marc