In case of synchronous DIO request (i.e. read(2) or write(2) for a file
opened with O_DIRECT), the patch submits fuse requests asynchronously, but
waits for their completions before return from fuse_direct_IO().
In case of asynchronous DIO request (i.e. libaio io_submit() or a file opened
with O_DIRECT), the patch submits fuse requests asynchronously and return
-EIOCBQUEUED immediately.
The only special case is async DIO extending file. Here the patch falls back
to old behaviour because we can't return -EIOCBQUEUED and update i_size later,
without i_mutex hold.
Signed-off-by: Maxim Patlasov <mpatla...@parallels.com>
---
fs/fuse/file.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 42 insertions(+), 2 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index c585158..ef6d3de 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2348,14 +2348,54 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct
iovec *iov,
ssize_t ret = 0;
struct file *file = NULL;
loff_t pos = 0;
+ struct inode *inode;
+ loff_t i_size;
+ size_t count = iov_length(iov, nr_segs);
+ struct kiocb *async_cb = NULL;
file = iocb->ki_filp;
pos = offset;
+ inode = file->f_mapping->host;
+ i_size = i_size_read(inode);
+
+ /* cannot write beyond eof asynchronously */
+ if (is_sync_kiocb(iocb) || (offset + count <= i_size) || rw != WRITE) {
+ struct fuse_io_priv *io;
+
+ io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
+ if (!io)
+ return -ENOMEM;
+
+ spin_lock_init(&io->lock);
+ io->reqs = 1;
+ io->bytes = -1;
+ io->size = 0;
+ io->offset = offset;
+ io->write = (rw == WRITE);
+ io->err = 0;
+ io->iocb = iocb;
+ iocb->private = io;
+
+ async_cb = iocb;
+ }
if (rw == WRITE)
- ret = __fuse_direct_write(file, iov, nr_segs, &pos, NULL);
+ ret = __fuse_direct_write(file, iov, nr_segs, &pos, async_cb);
else
- ret = __fuse_direct_read(file, iov, nr_segs, &pos, NULL);
+ ret = __fuse_direct_read(file, iov, nr_segs, &pos, async_cb);
+
+ if (async_cb) {
+ fuse_aio_complete(async_cb->private, ret == count ? 0 : -EIO,
+ -1);
+
+ if (!is_sync_kiocb(iocb))
+ return -EIOCBQUEUED;
+
+ ret = wait_on_sync_kiocb(iocb);
+
+ if (rw == WRITE && ret > 0)
+ fuse_write_update_size(inode, pos);
+ }
return ret;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
