https://bugzilla.kernel.org/show_bug.cgi?id=205957 --- Comment #12 from Andreas Dilger (adilger.kernelbugzilla@xxxxxxxxx) --- Created attachment 286491 --> https://bugzilla.kernel.org/attachment.cgi?id=286491&action=edit add ioctl(EXT4_IOC_SET_DIRLIMIT) to limit directory cookie size Totally untested prototype patch to add ioctl(fd, EXT4_IOC_SET_DIRLIMIT, 32) that could be used by glibc/QEMU to force ext4 to return a 32-bit directory offset cookie for the 64-bit getdirent64() syscall on a per-fd basis. The glibc patch would look something like the following, though this could potentially be done only once per open: + // It is affected by "__USE_FILE_OFFSET64" and "__USE_LARGEFILE64". + if (sizeof (outp->u.d_off) != sizeof (inp->k.d_off)) + (void *) ioctl (fd, EXT4_IOC_SET_DIRLIMIT, 32); // ignore error return + retval = INLINE_SYSCALL_CALL (getdents64, fd, kbuf, kbytes); If glibc/QEMU want ext4 to be totally transparent w.r.t. the behavior of the syscalls, then glibc/QEMU would need set the kernel task state so that is_32bit_api()->in_compat_syscall() return true and hash2pos() and related functions can determine this directly to return a 32-bit pos in a manner similar to x86. That is outside my area of expertise, so I can't really suggest how it might be done. It would also be possible to add some different logic to is_32bit_api() for ARM/etc. so that it is more transparent to userspace, but I don't know what it should check. -- You are receiving this mail because: You are watching the assignee of the bug.
