+#define EXT4_EPOCH_BITS 2
+#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
+#define EXT4_NSEC_MASK (~0UL << EXT4_EPOCH_BITS)
+
+/*
+ * Extended fields will fit into an inode if the filesystem was formatted
+ * with large inodes (-I 256 or larger) and there are not currently any EAs
+ * consuming all of the available space. For new inodes we always reserve
+ * enough space for the kernel's known extended fields, but for inodes
+ * created with an old kernel this might not have been the case. None of
+ * the extended inode fields is critical for correct filesystem operation.
+ * This macro checks if a certain field fits in the inode. Note that
+ * inode-size = GOOD_OLD_INODE_SIZE + i_extra_isize
+ */
+#define EXT4_FITS_IN_INODE(ext4_inode, einode, field) \
+ ((offsetof(typeof(*ext4_inode), field) + \
+ sizeof((ext4_inode)->field)) \
+ <= (EXT4_GOOD_OLD_INODE_SIZE + \
+ (einode)->i_extra_isize)) \
+
+static inline __le32 ext4_encode_extra_time(struct timespec *time)
+{
+ return cpu_to_le32((sizeof(time->tv_sec) > 4 ?
+ time->tv_sec >> 32 : 0) |
+ ((time->tv_nsec << 2) & EXT4_NSEC_MASK));
+}
+
+static inline void ext4_decode_extra_time(struct timespec *time, __le32 extra)
+{
+ if (sizeof(time->tv_sec) > 4)
+ time->tv_sec |= (__u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK)
+ << 32;
+ time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> 2;
+}
+
+#define EXT4_INODE_SET_XTIME(xtime, inode, raw_inode) \
+do { \
+ (raw_inode)->xtime = cpu_to_le32((inode)->xtime.tv_sec); \
+ if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra)) \
+ (raw_inode)->xtime ## _extra = \
+ ext4_encode_extra_time(&(inode)->xtime); \
+} while (0)
+
+#define EXT4_EINODE_SET_XTIME(xtime, einode, raw_inode) \
+do { \
+ if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime)) \
+ (raw_inode)->xtime = cpu_to_le32((einode)->xtime.tv_sec); \
+ if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra)) \
+ (raw_inode)->xtime ## _extra = \
+ ext4_encode_extra_time(&(einode)->xtime); \
+} while (0)
+
+#define EXT4_INODE_GET_XTIME(xtime, inode, raw_inode) \
+do { \
+ (inode)->xtime.tv_sec = (signed)le32_to_cpu((raw_inode)->xtime); \
+ if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra)) \
+ ext4_decode_extra_time(&(inode)->xtime, \
+ raw_inode->xtime ## _extra); \
+} while (0)
+
+#define EXT4_EINODE_GET_XTIME(xtime, einode, raw_inode) \
+do { \
+ if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime)) \
+ (einode)->xtime.tv_sec = \
+ (signed)le32_to_cpu((raw_inode)->xtime); \
+ if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra)) \
+ ext4_decode_extra_time(&(einode)->xtime, \
+ raw_inode->xtime ## _extra); \
+} while (0)
+