Kernel bump from 4.1.3-rt to 4.1.7-rt.

[kvmfornfv.git] / kernel / fs / xfs / xfs_inode.h

diff --git a/kernel/fs/xfs/xfs_inode.h b/kernel/fs/xfs/xfs_inode.h
index 8f22d20..ee26a60 100644 (file)
--- a/kernel/fs/xfs/xfs_inode.h
+++ b/kernel/fs/xfs/xfs_inode.h
@@ -284,9 +284,9 @@ static inline int xfs_isiflocked(struct xfs_inode *ip)
  * Flags for lockdep annotations.
  *
  * XFS_LOCK_PARENT - for directory operations that require locking a
- * parent directory inode and a child entry inode.  The parent gets locked
- * with this flag so it gets a lockdep subclass of 1 and the child entry
- * lock will have a lockdep subclass of 0.
+ * parent directory inode and a child entry inode. IOLOCK requires nesting,
+ * MMAPLOCK does not support this class, ILOCK requires a single subclass
+ * to differentiate parent from child.
  *
  * XFS_LOCK_RTBITMAP/XFS_LOCK_RTSUM - the realtime device bitmap and summary
  * inodes do not participate in the normal lock order, and thus have their
@@ -295,30 +295,63 @@ static inline int xfs_isiflocked(struct xfs_inode *ip)
  * XFS_LOCK_INUMORDER - for locking several inodes at the some time
  * with xfs_lock_inodes().  This flag is used as the starting subclass
  * and each subsequent lock acquired will increment the subclass by one.
- * So the first lock acquired will have a lockdep subclass of 4, the
- * second lock will have a lockdep subclass of 5, and so on. It is
- * the responsibility of the class builder to shift this to the correct
- * portion of the lock_mode lockdep mask.
+ * However, MAX_LOCKDEP_SUBCLASSES == 8, which means we are greatly
+ * limited to the subclasses we can represent via nesting. We need at least
+ * 5 inodes nest depth for the ILOCK through rename, and we also have to support
+ * XFS_ILOCK_PARENT, which gives 6 subclasses. Then we have XFS_ILOCK_RTBITMAP
+ * and XFS_ILOCK_RTSUM, which are another 2 unique subclasses, so that's all
+ * 8 subclasses supported by lockdep.
+ *
+ * This also means we have to number the sub-classes in the lowest bits of
+ * the mask we keep, and we have to ensure we never exceed 3 bits of lockdep
+ * mask and we can't use bit-masking to build the subclasses. What a mess.
+ *
+ * Bit layout:
+ *
+ * Bit         Lock Region
+ * 16-19       XFS_IOLOCK_SHIFT dependencies
+ * 20-23       XFS_MMAPLOCK_SHIFT dependencies
+ * 24-31       XFS_ILOCK_SHIFT dependencies
+ *
+ * IOLOCK values
+ *
+ * 0-3         subclass value
+ * 4-7         PARENT subclass values
+ *
+ * MMAPLOCK values
+ *
+ * 0-3         subclass value
+ * 4-7         unused
+ *
+ * ILOCK values
+ * 0-4         subclass values
+ * 5           PARENT subclass (not nestable)
+ * 6           RTBITMAP subclass (not nestable)
+ * 7           RTSUM subclass (not nestable)
+ *
  */
-#define XFS_LOCK_PARENT                1
-#define XFS_LOCK_RTBITMAP      2
-#define XFS_LOCK_RTSUM         3
-#define XFS_LOCK_INUMORDER     4
-
-#define XFS_IOLOCK_SHIFT       16
-#define        XFS_IOLOCK_PARENT       (XFS_LOCK_PARENT << XFS_IOLOCK_SHIFT)
-
-#define XFS_MMAPLOCK_SHIFT     20
-
-#define XFS_ILOCK_SHIFT                24
-#define        XFS_ILOCK_PARENT        (XFS_LOCK_PARENT << XFS_ILOCK_SHIFT)
-#define        XFS_ILOCK_RTBITMAP      (XFS_LOCK_RTBITMAP << XFS_ILOCK_SHIFT)
-#define        XFS_ILOCK_RTSUM         (XFS_LOCK_RTSUM << XFS_ILOCK_SHIFT)
-
-#define XFS_IOLOCK_DEP_MASK    0x000f0000
-#define XFS_MMAPLOCK_DEP_MASK  0x00f00000
-#define XFS_ILOCK_DEP_MASK     0xff000000
-#define XFS_LOCK_DEP_MASK      (XFS_IOLOCK_DEP_MASK | \
+#define XFS_IOLOCK_SHIFT               16
+#define XFS_IOLOCK_PARENT_VAL          4
+#define XFS_IOLOCK_MAX_SUBCLASS                (XFS_IOLOCK_PARENT_VAL - 1)
+#define XFS_IOLOCK_DEP_MASK            0x000f0000
+#define        XFS_IOLOCK_PARENT               (XFS_IOLOCK_PARENT_VAL << XFS_IOLOCK_SHIFT)
+
+#define XFS_MMAPLOCK_SHIFT             20
+#define XFS_MMAPLOCK_NUMORDER          0
+#define XFS_MMAPLOCK_MAX_SUBCLASS      3
+#define XFS_MMAPLOCK_DEP_MASK          0x00f00000
+
+#define XFS_ILOCK_SHIFT                        24
+#define XFS_ILOCK_PARENT_VAL           5
+#define XFS_ILOCK_MAX_SUBCLASS         (XFS_ILOCK_PARENT_VAL - 1)
+#define XFS_ILOCK_RTBITMAP_VAL         6
+#define XFS_ILOCK_RTSUM_VAL            7
+#define XFS_ILOCK_DEP_MASK             0xff000000
+#define        XFS_ILOCK_PARENT                (XFS_ILOCK_PARENT_VAL << XFS_ILOCK_SHIFT)
+#define        XFS_ILOCK_RTBITMAP              (XFS_ILOCK_RTBITMAP_VAL << XFS_ILOCK_SHIFT)
+#define        XFS_ILOCK_RTSUM                 (XFS_ILOCK_RTSUM_VAL << XFS_ILOCK_SHIFT)
+
+#define XFS_LOCK_SUBCLASS_MASK (XFS_IOLOCK_DEP_MASK | \
                                 XFS_MMAPLOCK_DEP_MASK | \
                                 XFS_ILOCK_DEP_MASK)