xfs: prepare xfs_break_layouts() for another layout type

[linux-2.6-microblaze.git] / fs / xfs / xfs_inode.h

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 1eebc53..e5b8498 100644 (file)
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -378,6 +378,20 @@ static inline void xfs_ifunlock(struct xfs_inode *ip)
 #define XFS_ILOCK_DEP(flags)   (((flags) & XFS_ILOCK_DEP_MASK) \
                                        >> XFS_ILOCK_SHIFT)
 
+/*
+ * Layouts are broken in the BREAK_WRITE case to ensure that
+ * layout-holders do not collide with local writes. Additionally,
+ * layouts are broken in the BREAK_UNMAP case to make sure the
+ * layout-holder has a consistent view of the file's extent map. While
+ * BREAK_WRITE breaks can be satisfied by recalling FL_LAYOUT leases,
+ * BREAK_UNMAP breaks additionally require waiting for busy dax-pages to
+ * go idle.
+ */
+enum layout_break_reason {
+        BREAK_WRITE,
+        BREAK_UNMAP,
+};
+
 /*
  * For multiple groups support: if S_ISGID bit is set in the parent
  * directory, group of new file is set to that of the parent, and
@@ -443,6 +457,8 @@ enum xfs_prealloc_flags {
 
 int    xfs_update_prealloc_flags(struct xfs_inode *ip,
                                  enum xfs_prealloc_flags flags);
+int    xfs_break_layouts(struct inode *inode, uint *iolock,
+               enum layout_break_reason reason);
 
 /* from xfs_iops.c */
 extern void xfs_setup_inode(struct xfs_inode *ip);