xfs: define locking primitives for realtime groups

Define helper functions to lock all metadata inodes related to a
realtime group.  There's not much to look at now, but this will become
important when we add per-rtgroup metadata files and online fsck code
for them.

Signed-off-by: Darrick J. Wong <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>

Author: Darrick J. Wong

fs/xfs/libxfs/xfs_rtgroup.c

@@ -149,3 +149,52 @@ xfs_update_last_rtgroup_size(
 	xfs_rtgroup_rele(rtg);
 	return 0;
 }
+
+/* Lock metadata inodes associated with this rt group. */
+void
+xfs_rtgroup_lock(
+	struct xfs_rtgroup	*rtg,
+	unsigned int		rtglock_flags)
+{
+	ASSERT(!(rtglock_flags & ~XFS_RTGLOCK_ALL_FLAGS));
+	ASSERT(!(rtglock_flags & XFS_RTGLOCK_BITMAP_SHARED) ||
+	       !(rtglock_flags & XFS_RTGLOCK_BITMAP));
+
+	if (rtglock_flags & XFS_RTGLOCK_BITMAP)
+		xfs_rtbitmap_lock(rtg_mount(rtg));
+	else if (rtglock_flags & XFS_RTGLOCK_BITMAP_SHARED)
+		xfs_rtbitmap_lock_shared(rtg_mount(rtg), XFS_RBMLOCK_BITMAP);
+}
+
+/* Unlock metadata inodes associated with this rt group. */
+void
+xfs_rtgroup_unlock(
+	struct xfs_rtgroup	*rtg,
+	unsigned int		rtglock_flags)
+{
+	ASSERT(!(rtglock_flags & ~XFS_RTGLOCK_ALL_FLAGS));
+	ASSERT(!(rtglock_flags & XFS_RTGLOCK_BITMAP_SHARED) ||
+	       !(rtglock_flags & XFS_RTGLOCK_BITMAP));
+
+	if (rtglock_flags & XFS_RTGLOCK_BITMAP)
+		xfs_rtbitmap_unlock(rtg_mount(rtg));
+	else if (rtglock_flags & XFS_RTGLOCK_BITMAP_SHARED)
+		xfs_rtbitmap_unlock_shared(rtg_mount(rtg), XFS_RBMLOCK_BITMAP);
+}
+
+/*
+ * Join realtime group metadata inodes to the transaction.  The ILOCKs will be
+ * released on transaction commit.
+ */
+void
+xfs_rtgroup_trans_join(
+	struct xfs_trans	*tp,
+	struct xfs_rtgroup	*rtg,
+	unsigned int		rtglock_flags)
+{
+	ASSERT(!(rtglock_flags & ~XFS_RTGLOCK_ALL_FLAGS));
+	ASSERT(!(rtglock_flags & XFS_RTGLOCK_BITMAP_SHARED));
+
+	if (rtglock_flags & XFS_RTGLOCK_BITMAP)
+		xfs_rtbitmap_trans_join(tp);
+}

fs/xfs/libxfs/xfs_rtgroup.h

@@ -197,6 +197,19 @@ xfs_rtxnum_t xfs_rtgroup_extents(struct xfs_mount *mp, xfs_rgnumber_t rgno);
 
 int xfs_update_last_rtgroup_size(struct xfs_mount *mp,
 		xfs_rgnumber_t prev_rgcount);
+
+/* Lock the rt bitmap inode in exclusive mode */
+#define XFS_RTGLOCK_BITMAP		(1U << 0)
+/* Lock the rt bitmap inode in shared mode */
+#define XFS_RTGLOCK_BITMAP_SHARED	(1U << 1)
+
+#define XFS_RTGLOCK_ALL_FLAGS	(XFS_RTGLOCK_BITMAP | \
+				 XFS_RTGLOCK_BITMAP_SHARED)
+
+void xfs_rtgroup_lock(struct xfs_rtgroup *rtg, unsigned int rtglock_flags);
+void xfs_rtgroup_unlock(struct xfs_rtgroup *rtg, unsigned int rtglock_flags);
+void xfs_rtgroup_trans_join(struct xfs_trans *tp, struct xfs_rtgroup *rtg,
+		unsigned int rtglock_flags);
 #else
 static inline void xfs_free_rtgroups(struct xfs_mount *mp,
 		xfs_rgnumber_t first_rgno, xfs_rgnumber_t end_rgno)
@@ -212,6 +225,9 @@ static inline int xfs_initialize_rtgroups(struct xfs_mount *mp,
 
 # define xfs_rtgroup_extents(mp, rgno)		(0)
 # define xfs_update_last_rtgroup_size(mp, rgno)	(-EOPNOTSUPP)
+# define xfs_rtgroup_lock(rtg, gf)		((void)0)
+# define xfs_rtgroup_unlock(rtg, gf)		((void)0)
+# define xfs_rtgroup_trans_join(tp, rtg, gf)	((void)0)
 #endif /* CONFIG_XFS_RT */
 
 #endif /* __LIBXFS_RTGROUP_H */