Fix assignment of quota IDs for XFS quotas

It appears that setting the FS_XFLAG_PROJINHERIT flag when
assigning a quota to a directory overrides any requested project
ID set (even in the same ioctl!) if a parent directory already
has a project ID. And our parent directories always do, as we set
the top-level directory to the base project ID for all volumes.

The result of this is that the inherit flag forces every
subdirectory to share the same project ID, and thus every time we
set a quota, it's set for everything using quotas - not just the
single directory we wanted to set it on.

Lacking the inherit flag made me a bit worried about
subdirectories, but I can confirm that the quotas themselves are
still function (creating a subdirectory in a dir with a quota set
and creating files in that directory still applies their size
towards the quota). There's a chance it would impact doing a
separate project ID in a subdirectory of a subdirectory but from
my read of the code that isn't supported at all right now.

Fixes RH Jira RHEL-18038

Signed-off-by: Matt Heon <mheon@redhat.com>

drivers/quota/projectquota_supported.go

@@ -19,16 +19,6 @@ package quota
 #include <linux/quota.h>
 #include <linux/dqblk_xfs.h>
 
-#ifndef FS_XFLAG_PROJINHERIT
-struct fsxattr {
-	__u32		fsx_xflags;
-	__u32		fsx_extsize;
-	__u32		fsx_nextents;
-	__u32		fsx_projid;
-	unsigned char	fsx_pad[12];
-};
-#define FS_XFLAG_PROJINHERIT	0x00000200
-#endif
 #ifndef FS_IOC_FSGETXATTR
 #define FS_IOC_FSGETXATTR		_IOR ('X', 31, struct fsxattr)
 #endif
@@ -357,7 +347,6 @@ func setProjectID(targetPath string, projectID uint32) error {
 		return fmt.Errorf("failed to get projid for %s: %w", targetPath, errno)
 	}
 	fsx.fsx_projid = C.__u32(projectID)
-	fsx.fsx_xflags |= C.FS_XFLAG_PROJINHERIT
 	_, _, errno = unix.Syscall(unix.SYS_IOCTL, getDirFd(dir), C.FS_IOC_FSSETXATTR,
 		uintptr(unsafe.Pointer(&fsx)))
 	if errno != 0 {