Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
new file mode 100644
index 0000000..8867e84
--- /dev/null
+++ b/fs/btrfs/space-info.h
@@ -0,0 +1,143 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BTRFS_SPACE_INFO_H
+#define BTRFS_SPACE_INFO_H
+
+struct btrfs_space_info {
+	spinlock_t lock;
+
+	u64 total_bytes;	/* total bytes in the space,
+				   this doesn't take mirrors into account */
+	u64 bytes_used;		/* total bytes used,
+				   this doesn't take mirrors into account */
+	u64 bytes_pinned;	/* total bytes pinned, will be freed when the
+				   transaction finishes */
+	u64 bytes_reserved;	/* total bytes the allocator has reserved for
+				   current allocations */
+	u64 bytes_may_use;	/* number of bytes that may be used for
+				   delalloc/allocations */
+	u64 bytes_readonly;	/* total bytes that are read only */
+
+	u64 max_extent_size;	/* This will hold the maximum extent size of
+				   the space info if we had an ENOSPC in the
+				   allocator. */
+
+	unsigned int full:1;	/* indicates that we cannot allocate any more
+				   chunks for this space */
+	unsigned int chunk_alloc:1;	/* set if we are allocating a chunk */
+
+	unsigned int flush:1;		/* set if we are trying to make space */
+
+	unsigned int force_alloc;	/* set if we need to force a chunk
+					   alloc for this space */
+
+	u64 disk_used;		/* total bytes used on disk */
+	u64 disk_total;		/* total bytes on disk, takes mirrors into
+				   account */
+
+	u64 flags;
+
+	/*
+	 * bytes_pinned is kept in line with what is actually pinned, as in
+	 * we've called update_block_group and dropped the bytes_used counter
+	 * and increased the bytes_pinned counter.  However this means that
+	 * bytes_pinned does not reflect the bytes that will be pinned once the
+	 * delayed refs are flushed, so this counter is inc'ed every time we
+	 * call btrfs_free_extent so it is a realtime count of what will be
+	 * freed once the transaction is committed.  It will be zeroed every
+	 * time the transaction commits.
+	 */
+	struct percpu_counter total_bytes_pinned;
+
+	struct list_head list;
+	/* Protected by the spinlock 'lock'. */
+	struct list_head ro_bgs;
+	struct list_head priority_tickets;
+	struct list_head tickets;
+	/*
+	 * tickets_id just indicates the next ticket will be handled, so note
+	 * it's not stored per ticket.
+	 */
+	u64 tickets_id;
+
+	struct rw_semaphore groups_sem;
+	/* for block groups in our same type */
+	struct list_head block_groups[BTRFS_NR_RAID_TYPES];
+	wait_queue_head_t wait;
+
+	struct kobject kobj;
+	struct kobject *block_group_kobjs[BTRFS_NR_RAID_TYPES];
+};
+
+struct reserve_ticket {
+	u64 bytes;
+	int error;
+	struct list_head list;
+	wait_queue_head_t wait;
+};
+
+static inline bool btrfs_mixed_space_info(struct btrfs_space_info *space_info)
+{
+	return ((space_info->flags & BTRFS_BLOCK_GROUP_METADATA) &&
+		(space_info->flags & BTRFS_BLOCK_GROUP_DATA));
+}
+
+/*
+ *
+ * Declare a helper function to detect underflow of various space info members
+ */
+#define DECLARE_SPACE_INFO_UPDATE(name, trace_name)			\
+static inline void							\
+btrfs_space_info_update_##name(struct btrfs_fs_info *fs_info,		\
+			       struct btrfs_space_info *sinfo,		\
+			       s64 bytes)				\
+{									\
+	const u64 abs_bytes = (bytes < 0) ? -bytes : bytes;		\
+	lockdep_assert_held(&sinfo->lock);				\
+	trace_update_##name(fs_info, sinfo, sinfo->name, bytes);	\
+	trace_btrfs_space_reservation(fs_info, trace_name,		\
+				      sinfo->flags, abs_bytes,		\
+				      bytes > 0);			\
+	if (bytes < 0 && sinfo->name < -bytes) {			\
+		WARN_ON(1);						\
+		sinfo->name = 0;					\
+		return;							\
+	}								\
+	sinfo->name += bytes;						\
+}
+
+DECLARE_SPACE_INFO_UPDATE(bytes_may_use, "space_info");
+DECLARE_SPACE_INFO_UPDATE(bytes_pinned, "pinned");
+
+int btrfs_init_space_info(struct btrfs_fs_info *fs_info);
+void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
+			     u64 total_bytes, u64 bytes_used,
+			     u64 bytes_readonly,
+			     struct btrfs_space_info **space_info);
+struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
+					       u64 flags);
+u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
+			  bool may_use_included);
+void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
+void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
+			   struct btrfs_space_info *info, u64 bytes,
+			   int dump_block_groups);
+int btrfs_reserve_metadata_bytes(struct btrfs_root *root,
+				 struct btrfs_block_rsv *block_rsv,
+				 u64 orig_bytes,
+				 enum btrfs_reserve_flush_enum flush);
+void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
+				struct btrfs_space_info *space_info);
+
+static inline void btrfs_space_info_free_bytes_may_use(
+				struct btrfs_fs_info *fs_info,
+				struct btrfs_space_info *space_info,
+				u64 num_bytes)
+{
+	spin_lock(&space_info->lock);
+	btrfs_space_info_update_bytes_may_use(fs_info, space_info, -num_bytes);
+	btrfs_try_granting_tickets(fs_info, space_info);
+	spin_unlock(&space_info->lock);
+}
+
+#endif /* BTRFS_SPACE_INFO_H */