From: Russ Fellows fuse_file_io_open() currently strips FOPEN_PARALLEL_DIRECT_WRITES whenever FOPEN_DIRECT_IO is absent. That rule is correct for the regular direct-IO path, but it is too strict for passthrough opens. Passthrough I/O already bypasses the page cache through the backing file, so it does not need FOPEN_DIRECT_IO to preserve direct-I/O semantics. Clearing the parallel-write flag for passthrough opens causes the kernel to drop the server's request for parallel direct writes before the passthrough write path ever sees it. Keep FOPEN_PARALLEL_DIRECT_WRITES for opens that also carry FOPEN_PASSTHROUGH, and continue to clear it for non-passthrough opens that lack FOPEN_DIRECT_IO. This is a prerequisite for passthrough write parallelism: without it, the subsequent shared-lock path never activates. Signed-off-by: Russ Fellows --- fs/fuse/iomode.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/fuse/iomode.c b/fs/fuse/iomode.c index c99e285f3..0301a48d8 100644 --- a/fs/fuse/iomode.c +++ b/fs/fuse/iomode.c @@ -216,9 +216,12 @@ int fuse_file_io_open(struct file *file, struct inode *inode) goto fail; /* - * FOPEN_PARALLEL_DIRECT_WRITES requires FOPEN_DIRECT_IO. + * FOPEN_PARALLEL_DIRECT_WRITES requires FOPEN_DIRECT_IO, except for + * passthrough opens which bypass the page cache regardless and do not + * need FOPEN_DIRECT_IO to guarantee direct I/O semantics. */ - if (!(ff->open_flags & FOPEN_DIRECT_IO)) + if (!(ff->open_flags & FOPEN_DIRECT_IO) && + !(ff->open_flags & FOPEN_PASSTHROUGH)) ff->open_flags &= ~FOPEN_PARALLEL_DIRECT_WRITES; /* -- 2.51.0