fuse: invalidate page cache after DIO and async DIO writes

This fixe does page cache invalidation after DIO and async DIO writes for
both O_DIRECT and FOPEN_DIRECT_IO cases.

Commit b359af8275a9 ("fuse: Invalidate the page cache after FOPEN_DIRECT_IO
write") fixed xfstests generic/209 for DIO writes in the FOPEN_DIRECT_IO
path. DIO writes without FOPEN_DIRECT_IO are already handled by
generic_file_direct_write().
However, async DIO writes (xfstests generic/451) remain unhandled.

After this fix:
- Async write with FUSE_ASYNC_DIO:
    invalidate in fuse_aio_invalidate_worker()

- Otherwise (Sync or async write without FUSE_ASYNC_DIO):
    - With FOPEN_DIRECT_IO:
        invalidate in fuse_direct_write_iter()
    - Without FOPEN_DIRECT_IO:
        invalidate in generic_file_direct_write()

Workqueue is required for async write invalidation to prevent deadlock:
calling it directly in the I/O end routine (which is in fuse worker thread
context) can block on a folio lock held by a buffered I/O thread waiting
for the same fuse worker thread.

Co-developed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Cheng Ding <cding@ddn.com>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/fs/super.h b/include/linux/fs/super.h
index f21ffbb6dea5..405612678115 100644
--- a/include/linux/fs/super.h
+++ b/include/linux/fs/super.h
@@ -235,4 +235,6 @@ int freeze_super(struct super_block *super, enum freeze_holder who,
 int thaw_super(struct super_block *super, enum freeze_holder who,
 	       const void *freeze_owner);
 
+int sb_init_dio_done_wq(struct super_block *sb);
+
 #endif /* _LINUX_FS_SUPER_H */