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@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: e78662e818f9 ("fuse: add a new fuse init flag to relax restrictions in no cache mode")
Signed-off-by: Bernd Schubert <bschubert@xxxxxxx>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
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 148a71b8b4d0..243f469cac07 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2476,7 +2476,10 @@ 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))
--
2.40.1
