There were multiple issues with direct_io_allow_mmap: - fuse_link_write_file() was missing, resulting in warnings in fuse_write_file_get() and EIO from msync() - "vma->vm_ops = &fuse_file_vm_ops" was not set, but especially fuse_page_mkwrite is needed.

The semantics of invalidate_inode_pages2() is so far not clearly defined in fuse_file_mmap. It dates back to commit 3121bfe76311 ("fuse: fix "direct_io" private mmap") Though, as direct_io_allow_mmap is a new feature, that was for MAP_PRIVATE only. As invalidate_inode_pages2() is calling into fuse_launder_folio() and writes out dirty pages, it should be safe to call invalidate_inode_pages2 for MAP_PRIVATE and MAP_SHARED as well.

Cc: Hao Xu howeyxu@tencent.com Cc: stable@vger.kernel.org Fixes: e78662e818f9 ("fuse: add a new fuse init flag to relax restrictions in no cache mode") Signed-off-by: Bernd Schubert bschubert@ddn.com Reviewed-by: Amir Goldstein amir73il@gmail.com --- fs/fuse/file.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c index a660f1f21540a..174aa16407c4b 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2475,7 +2475,10 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)

invalidate_inode_pages2(file->f_mapping);

- return generic_file_mmap(file, vma); + if (!(vma->vm_flags & VM_MAYSHARE)) { + /* MAP_PRIVATE */ + return generic_file_mmap(file, vma); + } }

if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))