On Sat, 2021-10-30 at 13:16 +0800, xiubli@xxxxxxxxxx wrote:
> From: Xiubo Li <xiubli@xxxxxxxxxx>
>
> Currently, if we end up reading more from the last object in the file
> than the i_size indicates then we'll end up returning the wrong length.
> Ensure that we cap the returned length and pos at the EOF.
>
> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
> ---
>
> Changed in V4:
> - move the i_size_read() into the while loop and use the lastest i_size
> read to do the check at the end of ceph_sync_read().
>
>
> fs/ceph/file.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 91173d3aa161..6005b430f6f7 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -847,6 +847,7 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
> ssize_t ret;
> u64 off = iocb->ki_pos;
> u64 len = iov_iter_count(to);
> + u64 i_size;
>
> dout("sync_read on file %p %llu~%u %s\n", file, off, (unsigned)len,
> (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
> @@ -870,7 +871,6 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
> struct page **pages;
> int num_pages;
> size_t page_off;
> - u64 i_size;
> bool more;
> int idx;
> size_t left;
> @@ -953,11 +953,14 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
> }
>
> if (off > iocb->ki_pos) {
> - if (ret >= 0 &&
> - iov_iter_count(to) > 0 && off >= i_size_read(inode))
> + if (off >= i_size) {
> *retry_op = CHECK_EOF;
> - ret = off - iocb->ki_pos;
> - iocb->ki_pos = off;
> + ret = i_size - iocb->ki_pos;
> + iocb->ki_pos = i_size;
> + } else {
> + ret = off - iocb->ki_pos;
> + iocb->ki_pos = off;
> + }
> }
>
> dout("sync_read result %zd retry_op %d\n", ret, *retry_op);
Thanks, looks good. I dropped the two patches I had merged for this on
Friday and merged this one instead.
--
Jeff Layton <jlayton@xxxxxxxxxx>
