https://bugzilla.kernel.org/show_bug.cgi?id=205957 --- Comment #15 from aladjev.andrew@xxxxxxxxx (aladjev.andrew@xxxxxxxxx) --- I've investigated mips related linux-user qemu and glibc source and mosaic looks complete. See qemu: https://github.com/qemu/qemu/blob/master/linux-user/syscall.c#L9465-L9536 emulates getdents via getdents or getdents64, but don't emulate getdents64 using getdents. Is it possible to emulate getdents64 using getdents? Yes, it was implemented in glibc for mips 64: https://github.com/bminor/glibc/blob/master/sysdeps/unix/sysv/linux/mips/mips64/getdents64.c#L49-L139 This emulation has been done because getdents64 was not available for some ancient kernels on mips n64. But this emulation should be a part of kernel. It has almost nothing to do with qemu or glibc. Qemu should just launch compat syscall instead of regular and that's it. Please see the following easy example: https://github.com/torvalds/linux/blob/master/fs/read_write.c#L322-L332 SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence) { return ksys_lseek(fd, offset, whence); } #ifdef CONFIG_COMPAT COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence) { return ksys_lseek(fd, offset, whence); } #endif We need to declear compat syscall in the same way, like: COMPAT_SYSCALL_DEFINE3(getdents64, unsigned int, fd, struct compat_linux_dirent64 __user *, dirent, unsigned int, count) "COMPAT_SYSCALL_DEFINE" will guarantee that "in_compat_syscall" will return true and ext4 will use 32 bit hash. Than we need to add this syscall to https://github.com/torvalds/linux/blob/master/arch/x86/entry/syscalls/syscall_64.tbl#L361-L402 -- You are receiving this mail because: You are watching the assignee of the bug.
