Merge tag 'for-6.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two fixes for NOCOW files, a regression fix in scrub and an assertion
  fix:

   - NOCOW fixes:
      - keep length of iomap direct io request in case of a failure
      - properly pass mode of extent reference checking, this can break
        some cases for swapfile

   - fix error value confusion when scrubbing a stripe

   - convert assertion to a proper error handling when loading global
     roots, reported by syzbot"

* tag 'for-6.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: scrub: fix a return value overwrite in scrub_stripe()
  btrfs: do not ASSERT() on duplicated global roots
  btrfs: can_nocow_file_extent should pass down args->strict from callers
  btrfs: fix iomap_begin length for nocow writes

fs/btrfs/disk-io.c

@@ -996,13 +996,18 @@ int btrfs_global_root_insert(struct btrfs_root *root)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct rb_node *tmp;
+	int ret = 0;
 
 	write_lock(&fs_info->global_root_lock);
 	tmp = rb_find_add(&root->rb_node, &fs_info->global_root_tree, global_root_cmp);
 	write_unlock(&fs_info->global_root_lock);
-	ASSERT(!tmp);
 
-	return tmp ? -EEXIST : 0;
+	if (tmp) {
+		ret = -EEXIST;
+		btrfs_warn(fs_info, "global root %llu %llu already exists",
+				root->root_key.objectid, root->root_key.offset);
+	}
+	return ret;
 }
 
 void btrfs_global_root_delete(struct btrfs_root *root)
@@ -2842,6 +2847,7 @@ static int __cold init_tree_roots(struct btrfs_fs_info *fs_info)
 			/* We can't trust the free space cache either */
 			btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
 
+			btrfs_warn(fs_info, "try to load backup roots slot %d", i);
 			ret = read_backup_root(fs_info, i);
 			backup_index = ret;
 			if (ret < 0)

fs/btrfs/inode.c

@@ -1864,7 +1864,7 @@ static int can_nocow_file_extent(struct btrfs_path *path,
 
 	ret = btrfs_cross_ref_exist(root, btrfs_ino(inode),
 				    key->offset - args->extent_offset,
-				    args->disk_bytenr, false, path);
+				    args->disk_bytenr, args->strict, path);
 	WARN_ON_ONCE(ret > 0 && is_freespace_inode);
 	if (ret != 0)
 		goto out;
@@ -7264,7 +7264,7 @@ static struct extent_map *create_io_em(struct btrfs_inode *inode, u64 start,
 static int btrfs_get_blocks_direct_write(struct extent_map **map,
 					 struct inode *inode,
 					 struct btrfs_dio_data *dio_data,
-					 u64 start, u64 len,
+					 u64 start, u64 *lenp,
 					 unsigned int iomap_flags)
 {
 	const bool nowait = (iomap_flags & IOMAP_NOWAIT);
@@ -7275,6 +7275,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
 	struct btrfs_block_group *bg;
 	bool can_nocow = false;
 	bool space_reserved = false;
+	u64 len = *lenp;
 	u64 prev_len;
 	int ret = 0;
 
@@ -7345,15 +7346,19 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
 		free_extent_map(em);
 		*map = NULL;
 
-		if (nowait)
-			return -EAGAIN;
+		if (nowait) {
+			ret = -EAGAIN;
+			goto out;
+		}
 
 		/*
 		 * If we could not allocate data space before locking the file
 		 * range and we can't do a NOCOW write, then we have to fail.
 		 */
-		if (!dio_data->data_space_reserved)
-			return -ENOSPC;
+		if (!dio_data->data_space_reserved) {
+			ret = -ENOSPC;
+			goto out;
+		}
 
 		/*
 		 * We have to COW and we have already reserved data space before,
@@ -7394,6 +7399,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
 		btrfs_delalloc_release_extents(BTRFS_I(inode), len);
 		btrfs_delalloc_release_metadata(BTRFS_I(inode), len, true);
 	}
+	*lenp = len;
 	return ret;
 }
 
@@ -7570,7 +7576,7 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start,
 
 	if (write) {
 		ret = btrfs_get_blocks_direct_write(&em, inode, dio_data,
-						    start, len, flags);
+						    start, &len, flags);
 		if (ret < 0)
 			goto unlock_err;
 		unlock_extents = true;

fs/btrfs/scrub.c

@@ -2266,7 +2266,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 	}
 out:
 	ret2 = flush_scrub_stripes(sctx);
-	if (!ret2)
+	if (!ret)
 		ret = ret2;
 	if (sctx->raid56_data_stripes) {
 		for (int i = 0; i < nr_data_stripes(map); i++)