add f_flags to struct statfs(64)

Add a flags field to help glibc implementing statvfs(3) efficiently.

We copy the flag values from glibc, and add a new ST_VALID flag to
denote that f_flags is implemented.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 29 insertions, 5 deletions

diff --git a/include/asm-generic/statfs.h b/include/asm-generic/statfs.h
index 3b4fb3e52f0d..0fd28e028de1 100644
--- a/include/asm-generic/statfs.h
+++ b/include/asm-generic/statfs.h
@@ -33,7 +33,8 @@ struct statfs {
         __kernel_fsid_t f_fsid;
         __statfs_word f_namelen;
         __statfs_word f_frsize;
-        __statfs_word f_spare[5];
+        __statfs_word f_flags;
+        __statfs_word f_spare[4];
 };
 
 /*
@@ -55,7 +56,8 @@ struct statfs64 {
         __kernel_fsid_t f_fsid;
         __statfs_word f_namelen;
         __statfs_word f_frsize;
-        __statfs_word f_spare[5];
+        __statfs_word f_flags;
+        __statfs_word f_spare[4];
 } ARCH_PACK_STATFS64;
 
 /* 
@@ -77,7 +79,8 @@ struct compat_statfs64 {
         __kernel_fsid_t f_fsid;
         __u32 f_namelen;
         __u32 f_frsize;
-        __u32 f_spare[5];
+        __u32 f_flags;
+        __u32 f_spare[4];
 } ARCH_PACK_COMPAT_STATFS64;
 
 #endif
diff --git a/include/linux/statfs.h b/include/linux/statfs.h
index b34cc829f98d..0166d320a75d 100644
--- a/include/linux/statfs.h
+++ b/include/linux/statfs.h
@@ -2,7 +2,6 @@
 #define _LINUX_STATFS_H
 
 #include <linux/types.h>
-
 #include <asm/statfs.h>
 
 struct kstatfs {
@@ -16,7 +15,29 @@ struct kstatfs {
         __kernel_fsid_t f_fsid;
         long f_namelen;
         long f_frsize;
-        long f_spare[5];
+        long f_flags;
+        long f_spare[4];
 };
 
+/*
+ * Definitions for the flag in f_flag.
+ *
+ * Generally these flags are equivalent to the MS_ flags used in the mount
+ * ABI.  The exception is ST_VALID which has the same value as MS_REMOUNT
+ * which doesn't make any sense for statfs.
+ */
+#define ST_RDONLY       0x0001  /* mount read-only */
+#define ST_NOSUID       0x0002  /* ignore suid and sgid bits */
+#define ST_NODEV        0x0004  /* disallow access to device special files */
+#define ST_NOEXEC       0x0008  /* disallow program execution */
+#define ST_SYNCHRONOUS  0x0010  /* writes are synced at once */
+#define ST_VALID        0x0020  /* f_flags support is implemented */
+#define ST_MANDLOCK     0x0040  /* allow mandatory locks on an FS */
+/* 0x0080 used for ST_WRITE in glibc */
+/* 0x0100 used for ST_APPEND in glibc */
+/* 0x0200 used for ST_IMMUTABLE in glibc */
+#define ST_NOATIME      0x0400  /* do not update access times */
+#define ST_NODIRATIME   0x0800  /* do not update directory access times */
+#define ST_RELATIME     0x1000  /* update atime relative to mtime/ctime */
+
 #endif