[PATCH 9/9] aio: implement IOCB_CMD_FSYNC and IOCB_CMD_FDSYNC

[Christoph Hellwig]

Simple workqueue offload for now, but prepared for adding a real aio_fsync
method if the need arises.  Based on an earlier patch from Dave Chinner.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 fs/aio.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/fs/aio.c b/fs/aio.c
index da87cbf7c67a..79d3eb3d2dd9 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -156,9 +156,16 @@ struct kioctx {
        unsigned                id;
 };
 
+struct fsync_iocb {
+       struct work_struct      work;
+       struct file             *file;
+       bool                    datasync;
+};
+
 struct aio_kiocb {
        union {
                struct kiocb            rw;
+               struct fsync_iocb       fsync;
        };
 
        struct kioctx           *ki_ctx;
@@ -1565,6 +1572,43 @@ static ssize_t aio_write(struct kiocb *req, struct iocb 
*iocb, bool vectored,
        return ret;
 }
 
+static void aio_fsync_work(struct work_struct *work)
+{
+       struct fsync_iocb *req = container_of(work, struct fsync_iocb, work);
+       int ret;
+
+       ret = vfs_fsync(req->file, req->datasync);
+       fput(req->file);
+       aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0);
+}
+
+static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync)
+{
+       int ret;
+
+       if (iocb->aio_buf)
+               return -EINVAL;
+       if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
+               return -EINVAL;
+
+       req->file = fget(iocb->aio_fildes);
+       if (unlikely(!req->file))
+               return -EBADF;
+
+       ret = -EINVAL;
+       if (!req->file->f_op->fsync)
+               goto out_fput;
+
+       req->datasync = datasync;
+       INIT_WORK(&req->work, aio_fsync_work);
+       schedule_work(&req->work);
+       return -EIOCBQUEUED;
+out_fput:
+       if (unlikely(ret && ret != -EIOCBQUEUED))
+               fput(req->file);
+       return ret;
+}
+
 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
                         struct iocb *iocb, bool compat)
 {
@@ -1628,6 +1672,12 @@ static int io_submit_one(struct kioctx *ctx, struct iocb 
__user *user_iocb,
        case IOCB_CMD_PWRITEV:
                ret = aio_write(&req->rw, iocb, true, compat);
                break;
+       case IOCB_CMD_FSYNC:
+               ret = aio_fsync(&req->fsync, iocb, false);
+               break;
+       case IOCB_CMD_FDSYNC:
+               ret = aio_fsync(&req->fsync, iocb, true);
+               break;
        default:
                pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
                ret = -EINVAL;
-- 
2.14.2