This is a note to let you know that I've just added the patch titled
fuse: fix VM_MAYSHARE and direct_io_allow_mmap
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fuse-fix-vm_mayshare-and-direct_io_allow_mmap.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2a30a0975895e66259482267dabd286416bf52d4
Author: Bernd Schubert <bschubert@xxxxxxx>
Date: Tue Dec 12 14:33:23 2023 +0100
fuse: fix VM_MAYSHARE and direct_io_allow_mmap
[ Upstream commit 9511176bbaee0ac60ecc84e7b01cf5972a59ea17 ]
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>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 148a71b8b4d0e..b9cff9b6ca1b8 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2468,7 +2468,8 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
return fuse_dax_mmap(file, vma);
if (ff->open_flags & FOPEN_DIRECT_IO) {
- /* Can't provide the coherency needed for MAP_SHARED
+ /*
+ * Can't provide the coherency needed for MAP_SHARED
* if FUSE_DIRECT_IO_ALLOW_MMAP isn't set.
*/
if ((vma->vm_flags & VM_MAYSHARE) && !fc->direct_io_allow_mmap)
@@ -2476,7 +2477,10 @@ 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))
