Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index dec14b7..ee6f605 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -14,6 +14,7 @@
 #include "disk-io.h"
 #include "transaction.h"
 #include "dev-replace.h"
+#include "block-group.h"
 
 #undef DEBUG
 
@@ -376,26 +377,28 @@
 		goto error;
 	}
 
+	/* Insert extent in reada tree + all per-device trees, all or nothing */
+	down_read(&fs_info->dev_replace.rwsem);
 	ret = radix_tree_preload(GFP_KERNEL);
-	if (ret)
+	if (ret) {
+		up_read(&fs_info->dev_replace.rwsem);
 		goto error;
+	}
 
-	/* insert extent in reada_tree + all per-device trees, all or nothing */
-	btrfs_dev_replace_read_lock(&fs_info->dev_replace);
 	spin_lock(&fs_info->reada_lock);
 	ret = radix_tree_insert(&fs_info->reada_tree, index, re);
 	if (ret == -EEXIST) {
 		re_exist = radix_tree_lookup(&fs_info->reada_tree, index);
 		re_exist->refcnt++;
 		spin_unlock(&fs_info->reada_lock);
-		btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
 		radix_tree_preload_end();
+		up_read(&fs_info->dev_replace.rwsem);
 		goto error;
 	}
 	if (ret) {
 		spin_unlock(&fs_info->reada_lock);
-		btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
 		radix_tree_preload_end();
+		up_read(&fs_info->dev_replace.rwsem);
 		goto error;
 	}
 	radix_tree_preload_end();
@@ -437,13 +440,13 @@
 			}
 			radix_tree_delete(&fs_info->reada_tree, index);
 			spin_unlock(&fs_info->reada_lock);
-			btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
+			up_read(&fs_info->dev_replace.rwsem);
 			goto error;
 		}
 		have_zone = 1;
 	}
 	spin_unlock(&fs_info->reada_lock);
-	btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
+	up_read(&fs_info->dev_replace.rwsem);
 
 	if (!have_zone)
 		goto error;
@@ -636,6 +639,35 @@
 	return 1;
 }
 
+static int reada_tree_block_flagged(struct btrfs_fs_info *fs_info, u64 bytenr,
+				    int mirror_num, struct extent_buffer **eb)
+{
+	struct extent_buffer *buf = NULL;
+	int ret;
+
+	buf = btrfs_find_create_tree_block(fs_info, bytenr);
+	if (IS_ERR(buf))
+		return 0;
+
+	set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
+
+	ret = read_extent_buffer_pages(buf, WAIT_PAGE_LOCK, mirror_num);
+	if (ret) {
+		free_extent_buffer_stale(buf);
+		return ret;
+	}
+
+	if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
+		free_extent_buffer_stale(buf);
+		return -EIO;
+	} else if (extent_buffer_uptodate(buf)) {
+		*eb = buf;
+	} else {
+		free_extent_buffer(buf);
+	}
+	return 0;
+}
+
 static int reada_start_machine_dev(struct btrfs_device *dev)
 {
 	struct btrfs_fs_info *fs_info = dev->fs_info;
@@ -745,6 +777,7 @@
 	u64 total = 0;
 	int i;
 
+again:
 	do {
 		enqueued = 0;
 		mutex_lock(&fs_devices->device_list_mutex);
@@ -756,6 +789,10 @@
 		mutex_unlock(&fs_devices->device_list_mutex);
 		total += enqueued;
 	} while (enqueued && total < 10000);
+	if (fs_devices->seed) {
+		fs_devices = fs_devices->seed;
+		goto again;
+	}
 
 	if (enqueued == 0)
 		return;