Sorry I put mailing list in  "cc",  but not "to"

Andreas

Thank you for pointing that out

at this moment "total" is READ_BUF_SIZE

```c
/* emacs/src/fileio.c:4613 */

/* In the following loop, HOW_MUCH contains the total bytes read so
   far for a regular file, and not changed for a special file.  But,
   before exiting the loop, it is set to a negative value if I/O
   error occurs.  */
how_much = 0;
```

I have confirmed the file is not seekable on my side using,  which is different from /proc files

```c
/* test.c:11 */

int fd = open("/proc/2051/arch_status", O_RDONLY);
int sek = lseek(fd, 0, SEEK_CUR);
printf("proc file is seekable %d\n", sek); // returns 0

fd = open("/run/test.json", O_RDONLY);
sek = lseek(fd, 0, SEEK_CUR);
printf("fuse file is seekable %d\n", sek); // returns -1
```

I think it hits this block. But I don't see anything special to increase the count. Could that mean emacs only reads "READ_BUF_SIZE" amount of data?

```c
/* emacs/src/fileio.c:4627 */

while (how_much < total)
  {
    /* `try' is reserved in some compilers (Microsoft C).  */
    ptrdiff_t trytry = min (total - how_much, READ_BUF_SIZE);
    ptrdiff_t this;

    if (!seekable && NILP (end))
```

Should the fix be quitting at actual io?