f_flags in Linux statfs implementation.

The 2.6.36 kernel provides an additional field in the statfs results.
Use this value in the statvfs emulation to avoid filling in f_flag
the hard way.

ChangeLog

@@ -1,5 +1,18 @@
 2010-08-11  Ulrich Drepper  <drepper@redhat.com>
 
+	* sysdeps/unix/sysv/linux/bits/statfs.h (struct statfs): Add f_flags
+	field.
+	(struct statfs64): Likewise.
+	(_STATFS_F_FLAGS): Define.
+	* sysdeps/unix/sysv/linux/s390/bits/statfs.h: Likewise.
+	* sysdeps/unix/sysv/linux/internal_statvfs.c (__statvfs_getflags):
+	Don't define if __ASSUME_STATFS_F_FLAGS is defined.
+	(ST_VALID): Define locally.
+	(INTERNAL_STATVFS): If f_flags has ST_VALID set don't call
+	__statvfs_getflags, use the provided value.
+	* sysdeps/unix/sysv/linux/kernel-features.h: Define
+	__ASSUME_STATFS_F_FLAGS.
+
 	* sysdeps/unix/sysv/linux/sys/inotify.h (IN_EXCL_UNLINK): Define.
 
 	* sysdeps/unix/sysv/linux/Makefile [subdir=misc] (sysdep_headers):

sysdeps/unix/sysv/linux/bits/statfs.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 1997, 1998, 2000, 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 1997,1998,2000,2002,2003,2010 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -42,7 +42,8 @@ struct statfs
     __fsid_t f_fsid;
     __SWORD_TYPE f_namelen;
     __SWORD_TYPE f_frsize;
-    __SWORD_TYPE f_spare[5];
+    __SWORD_TYPE f_flags;
+    __SWORD_TYPE f_spare[4];
   };
 
 #ifdef __USE_LARGEFILE64
@@ -58,10 +59,12 @@ struct statfs64
     __fsid_t f_fsid;
     __SWORD_TYPE f_namelen;
     __SWORD_TYPE f_frsize;
-    __SWORD_TYPE f_spare[5];
+    __SWORD_TYPE f_flags;
+    __SWORD_TYPE f_spare[4];
   };
 #endif
 
 /* Tell code we have these members.  */
 #define _STATFS_F_NAMELEN
 #define _STATFS_F_FRSIZE
+#define _STATFS_F_FLAGS

sysdeps/unix/sysv/linux/internal_statvfs.c

@@ -29,6 +29,11 @@
 #include <sys/statfs.h>
 #include <sys/statvfs.h>
 #include "linux_fsinfo.h"
+#include "kernel-features.h"
+
+
+/* Special internal-only bit value.  */
+#define ST_VALID 0x0020
 
 
 #ifndef STATFS
@@ -37,6 +42,7 @@
 # define INTERNAL_STATVFS __internal_statvfs
 
 
+# ifndef __ASSUME_STATFS_F_FLAGS
 int
 __statvfs_getflags (const char *name, int fstype, struct stat64 *st)
 {
@@ -200,6 +206,7 @@ __statvfs_getflags (const char *name, int fstype, struct stat64 *st)
 
   return result;
 }
+# endif
 #else
 extern int __statvfs_getflags (const char *name, int fstype,
 			       struct stat64 *st);
@@ -240,9 +247,14 @@ INTERNAL_STATVFS (const char *name, struct STATVFS *buf,
   /* XXX I have no idea how to compute f_favail.  Any idea???  */
   buf->f_favail = buf->f_ffree;
 
-  /* Determining the flags is tricky.  We have to read /proc/mounts or
+#ifndef __ASSUME_STATFS_F_FLAGS
-     the /etc/mtab file and search for the entry which matches the given
+  if ((fsbuf->f_flags & ST_VALID) == 0)
-     file.  The way we can test for matching filesystem is using the
+    /* Determining the flags is tricky.  We have to read /proc/mounts or
-     device number.  */
+       the /etc/mtab file and search for the entry which matches the given
-  buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
+       file.  The way we can test for matching filesystem is using the
+       device number.  */
+    buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
+  else
+#endif
+    buf->f_flag = fsbuf->f_flags ^ ST_VALID;
 }

sysdeps/unix/sysv/linux/kernel-features.h

@@ -530,3 +530,8 @@
 #if __LINUX_KERNEL_VERSION >= 0x020621
 # define __ASSUME_RECVMMSG	1
 #endif
+
+/* statfs fills in f_flags since 2.6.36.  */
+#if __LINUX_KERNEL_VERSION >= 0x020624
+# define __ASSUME_STATFS_F_FLAGS	1
+#endif

sysdeps/unix/sysv/linux/s390/bits/statfs.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 1997, 1998, 2000, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 1997, 1998, 2000, 2003, 2010 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -42,7 +42,8 @@ struct statfs
     __fsid_t f_fsid;
     int f_namelen;
     int f_frsize;
-    int f_spare[5];
+    int f_flags;
+    int f_spare[4];
   };
 
 #ifdef __USE_LARGEFILE64
@@ -58,10 +59,12 @@ struct statfs64
     __fsid_t f_fsid;
     int f_namelen;
     int f_frsize;
-    int f_spare[5];
+    int f_flags;
+    int f_spare[4];
   };
 #endif
 
 /* Tell code we have this member.  */
 #define _STATFS_F_NAMELEN
 #define _STATFS_F_FRSIZE
+#define _STATFS_F_FLAGS