erofs: add erofs_sb_free() helper

Unify the common parts of erofs_fc_free() and erofs_kill_sb() as
erofs_sb_free().

Thus, fput() in erofs_fc_get_tree() is no longer needed, too.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241212133504.2047178-1-hsiangkao@linux.alibaba.com

Author: hsiangkao

fs/erofs/super.c

@@ -703,16 +703,19 @@ static int erofs_fc_get_tree(struct fs_context *fc)
 			GET_TREE_BDEV_QUIET_LOOKUP : 0);
 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
 	if (ret == -ENOTBLK) {
+		struct file *file;
+
 		if (!fc->source)
 			return invalf(fc, "No source specified");
-		sbi->fdev = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
-		if (IS_ERR(sbi->fdev))
-			return PTR_ERR(sbi->fdev);
+
+		file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
+		if (IS_ERR(file))
+			return PTR_ERR(file);
+		sbi->fdev = file;
 
 		if (S_ISREG(file_inode(sbi->fdev)->i_mode) &&
 		    sbi->fdev->f_mapping->a_ops->read_folio)
 			return get_tree_nodev(fc, erofs_fc_fill_super);
-		fput(sbi->fdev);
 	}
 #endif
 	return ret;
@@ -763,19 +766,24 @@ static void erofs_free_dev_context(struct erofs_dev_context *devs)
 	kfree(devs);
 }
 
-static void erofs_fc_free(struct fs_context *fc)
+static void erofs_sb_free(struct erofs_sb_info *sbi)
 {
-	struct erofs_sb_info *sbi = fc->s_fs_info;
-
-	if (!sbi)
-		return;
-
 	erofs_free_dev_context(sbi->devs);
 	kfree(sbi->fsid);
 	kfree(sbi->domain_id);
+	if (sbi->fdev)
+		fput(sbi->fdev);
 	kfree(sbi);
 }
 
+static void erofs_fc_free(struct fs_context *fc)
+{
+	struct erofs_sb_info *sbi = fc->s_fs_info;
+
+	if (sbi) /* free here if an error occurs before transferring to sb */
+		erofs_sb_free(sbi);
+}
+
 static const struct fs_context_operations erofs_context_ops = {
 	.parse_param	= erofs_fc_parse_param,
 	.get_tree       = erofs_fc_get_tree,
@@ -813,15 +821,9 @@ static void erofs_kill_sb(struct super_block *sb)
 		kill_anon_super(sb);
 	else
 		kill_block_super(sb);
-
-	erofs_free_dev_context(sbi->devs);
 	fs_put_dax(sbi->dax_dev, NULL);
 	erofs_fscache_unregister_fs(sb);
-	kfree(sbi->fsid);
-	kfree(sbi->domain_id);
-	if (sbi->fdev)
-		fput(sbi->fdev);
-	kfree(sbi);
+	erofs_sb_free(sbi);
 	sb->s_fs_info = NULL;
 }