Reviewed-by: Shirish Pargaonkar <spargaonkar@xxxxxxxx>
On Mon, Jul 21, 2014 at 10:45 AM, Pavel Shilovsky <pshilovsky@xxxxxxxxx> wrote:
> If a server changes maximum buffer size for read requests (rsize)
> on reconnect we can fail on repeating with a big size buffer on
> -EAGAIN error in cifs_read. Fix this by checking rsize all the
> time before repeating requests.
>
> Signed-off-by: Pavel Shilovsky <pshilovsky@xxxxxxxxx>
> ---
> fs/cifs/file.c | 26 ++++++++++++++------------
> 1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index bbc3859..00b2a25 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -3148,18 +3148,19 @@ cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
>
> for (total_read = 0, cur_offset = read_data; read_size > total_read;
> total_read += bytes_read, cur_offset += bytes_read) {
> - current_read_size = min_t(uint, read_size - total_read, rsize);
> - /*
> - * For windows me and 9x we do not want to request more than it
> - * negotiated since it will refuse the read then.
> - */
> - if ((tcon->ses) && !(tcon->ses->capabilities &
> + do {
> + current_read_size = min_t(uint, read_size - total_read,
> + rsize);
> + /*
> + * For windows me and 9x we do not want to request more
> + * than it negotiated since it will refuse the read
> + * then.
> + */
> + if ((tcon->ses) && !(tcon->ses->capabilities &
> tcon->ses->server->vals->cap_large_files)) {
> - current_read_size = min_t(uint, current_read_size,
> - CIFSMaxBufSize);
> - }
> - rc = -EAGAIN;
> - while (rc == -EAGAIN) {
> + current_read_size = min_t(uint,
> + current_read_size, CIFSMaxBufSize);
> + }
> if (open_file->invalidHandle) {
> rc = cifs_reopen_file(open_file, true);
> if (rc != 0)
> @@ -3172,7 +3173,8 @@ cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
> rc = server->ops->sync_read(xid, open_file, &io_parms,
> &bytes_read, &cur_offset,
> &buf_type);
> - }
> + } while (rc == -EAGAIN);
> +
> if (rc || (bytes_read == 0)) {
> if (total_read) {
> break;
> --
> 1.8.1.2
>
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