1 files changed, 75 insertions, 0 deletions
diff --git a/fs/xfs/xfs_extfree_item.h b/fs/xfs/xfs_extfree_item.h
new file mode 100644
index 000000000..cd2860c87
--- /dev/null
+++ b/fs/xfs/xfs_extfree_item.h
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000,2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#ifndef	__XFS_EXTFREE_ITEM_H__
+#define	__XFS_EXTFREE_ITEM_H__
+
+/* kernel only EFI/EFD definitions */
+
+struct xfs_mount;
+struct kmem_zone;
+
+/*
+ * Max number of extents in fast allocation path.
+ */
+#define	XFS_EFI_MAX_FAST_EXTENTS	16
+
+/*
+ * This is the "extent free intention" log item.  It is used to log the fact
+ * that some extents need to be free.  It is used in conjunction with the
+ * "extent free done" log item described below.
+ *
+ * The EFI is reference counted so that it is not freed prior to both the EFI
+ * and EFD being committed and unpinned. This ensures the EFI is inserted into
+ * the AIL even in the event of out of order EFI/EFD processing. In other words,
+ * an EFI is born with two references:
+ *
+ * 	1.) an EFI held reference to track EFI AIL insertion
+ * 	2.) an EFD held reference to track EFD commit
+ *
+ * On allocation, both references are the responsibility of the caller. Once the
+ * EFI is added to and dirtied in a transaction, ownership of reference one
+ * transfers to the transaction. The reference is dropped once the EFI is
+ * inserted to the AIL or in the event of failure along the way (e.g., commit
+ * failure, log I/O error, etc.). Note that the caller remains responsible for
+ * the EFD reference under all circumstances to this point. The caller has no
+ * means to detect failure once the transaction is committed, however.
+ * Therefore, an EFD is required after this point, even in the event of
+ * unrelated failure.
+ *
+ * Once an EFD is allocated and dirtied in a transaction, reference two
+ * transfers to the transaction. The EFD reference is dropped once it reaches
+ * the unpin handler. Similar to the EFI, the reference also drops in the event
+ * of commit failure or log I/O errors. Note that the EFD is not inserted in the
+ * AIL, so at this point both the EFI and EFD are freed.
+ */
+struct xfs_efi_log_item {
+	struct xfs_log_item	efi_item;
+	atomic_t		efi_refcount;
+	atomic_t		efi_next_extent;
+	xfs_efi_log_format_t	efi_format;
+};
+
+/*
+ * This is the "extent free done" log item.  It is used to log
+ * the fact that some extents earlier mentioned in an efi item
+ * have been freed.
+ */
+struct xfs_efd_log_item {
+	struct xfs_log_item	efd_item;
+	struct xfs_efi_log_item *efd_efip;
+	uint			efd_next_extent;
+	xfs_efd_log_format_t	efd_format;
+};
+
+/*
+ * Max number of extents in fast allocation path.
+ */
+#define	XFS_EFD_MAX_FAST_EXTENTS	16
+
+extern struct kmem_zone	*xfs_efi_zone;
+extern struct kmem_zone	*xfs_efd_zone;
+
+#endif	/* __XFS_EXTFREE_ITEM_H__ */