On 2/8/19 3:36 PM, Jann Horn wrote:
> On Fri, Feb 8, 2019 at 6:34 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
>> From: Christoph Hellwig <hch@xxxxxx>
>>
>> Add a new fsync opcode, which either syncs a range if one is passed,
>> or the whole file if the offset and length fields are both cleared
>> to zero. A flag is provided to use fdatasync semantics, that is only
>> force out metadata which is required to retrieve the file data, but
>> not others like metadata.
>>
>> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>> ---
> [...]
>> +static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
>> + bool force_nonblock)
>> +{
>> + struct io_ring_ctx *ctx = req->ctx;
>> + loff_t sqe_off = READ_ONCE(sqe->off);
>> + loff_t sqe_len = READ_ONCE(sqe->len);
>> + loff_t end = sqe_off + sqe_len;
>> + unsigned fsync_flags;
>> + struct file *file;
>> + int ret, fd;
>> +
>> + /* fsync always requires a blocking context */
>> + if (force_nonblock)
>> + return -EAGAIN;
>> +
>> + if (unlikely(sqe->addr || sqe->ioprio))
>> + return -EINVAL;
>> +
>> + fsync_flags = READ_ONCE(sqe->fsync_flags);
>> + if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC))
>> + return -EINVAL;
>> +
>> + fd = READ_ONCE(sqe->fd);
>> + file = fget(fd);
>
> This always runs on the workqueue, right? Is it possible to call
> fget() on a workqueue?
Oops yes, I've now split that into a io_prep_fsync() and io_fsync()
part so that it works correctly with this new method. Also added a
liburing test for this.
--
Jens Axboe
