fuse: add flag to turn on async direct IO
Without async DIO write requests to a single file were always serialized.
With async DIO that's no longer the case.
So don't turn on async DIO by default for fear of breaking backward
compatibility.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 1f8e3d6..6ab7ca4 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2371,14 +2371,14 @@
loff_t offset, unsigned long nr_segs)
{
ssize_t ret = 0;
- struct file *file = NULL;
+ struct file *file = iocb->ki_filp;
+ struct fuse_file *ff = file->private_data;
loff_t pos = 0;
struct inode *inode;
loff_t i_size;
size_t count = iov_length(iov, nr_segs);
struct fuse_io_priv *io;
- file = iocb->ki_filp;
pos = offset;
inode = file->f_mapping->host;
i_size = i_size_read(inode);
@@ -2403,9 +2403,9 @@
io->file = file;
/*
* By default, we want to optimize all I/Os with async request
- * submission to the client filesystem.
+ * submission to the client filesystem if supported.
*/
- io->async = 1;
+ io->async = ff->fc->async_dio;
io->iocb = iocb;
/*
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 53b830e..fde7249 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -541,6 +541,9 @@
/** Does the filesystem want adaptive readdirplus? */
unsigned readdirplus_auto:1;
+ /** Does the filesystem support asynchronous direct-IO submission? */
+ unsigned async_dio:1;
+
/** The number of requests waiting for completion */
atomic_t num_waiting;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 17ec1f7..6201f81 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -871,6 +871,8 @@
fc->do_readdirplus = 1;
if (arg->flags & FUSE_READDIRPLUS_AUTO)
fc->readdirplus_auto = 1;
+ if (arg->flags & FUSE_ASYNC_DIO)
+ fc->async_dio = 1;
} else {
ra_pages = fc->max_read / PAGE_CACHE_SIZE;
fc->no_lock = 1;
@@ -898,7 +900,7 @@
FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
- FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO;
+ FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);