On May 13, 2025 2:53:23 AM PDT, Arnd Bergmann <a...@arndb.de> wrote: >On Tue, May 13, 2025, at 11:17, Andrey Albershteyn wrote: > >> >> long syscall(SYS_file_getattr, int dirfd, const char *pathname, >> struct fsxattr *fsx, size_t size, unsigned int at_flags); >> long syscall(SYS_file_setattr, int dirfd, const char *pathname, >> struct fsxattr *fsx, size_t size, unsigned int at_flags); > >I don't think we can have both the "struct fsxattr" from the uapi >headers, and a variable size as an additional argument. I would >still prefer not having the extensible structure at all and just >use fsxattr, but if you want to make it extensible in this way, >it should use a different structure (name). Otherwise adding >fields after fsx_pad[] would break the ioctl interface. > >I also find the bit confusing where the argument contains both >"ignored but assumed zero" flags, and "required to be zero" >flags depending on whether it's in the fsx_pad[] field or >after it. This would be fine if it was better documented. > > >> fsx.fsx_xflags |= FS_XFLAG_NODUMP; >> error = syscall(468, dfd, "./foo", &fsx, 0); > >The example still uses the calling conventions from a previous >version. > > Arnd
Well, ioctls carry the structure size in the ioctl number, so changing the structure size would change the ioctl number with it.
