erofs: convert to use the new mount fs_context api

Convert the erofs to use new internal mount API as the old one will
be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20200529104836.17843-1-hsiangkao@redhat.com
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>

fs/erofs/internal.h

@@ -46,6 +46,17 @@ typedef u64 erofs_off_t;
 /* data type for filesystem-wide blocks number */
 typedef u32 erofs_blk_t;
 
+struct erofs_fs_context {
+#ifdef CONFIG_EROFS_FS_ZIP
+	/* current strategy of how to use managed cache */
+	unsigned char cache_strategy;
+
+	/* threshold for decompression synchronously */
+	unsigned int max_sync_decompress_pages;
+#endif
+	unsigned int mount_opt;
+};
+
 struct erofs_sb_info {
 #ifdef CONFIG_EROFS_FS_ZIP
 	/* list for all registered superblocks, mainly for shrinker */
@@ -55,14 +66,8 @@ struct erofs_sb_info {
 	/* managed XArray arranged in physical block number */
 	struct xarray managed_pslots;
 
-	/* threshold for decompression synchronously */
-	unsigned int max_sync_decompress_pages;
-
 	unsigned int shrinker_run_no;
 
-	/* current strategy of how to use managed cache */
-	unsigned char cache_strategy;
-
 	/* pseudo inode to manage cached pages */
 	struct inode *managed_cache;
 #endif	/* CONFIG_EROFS_FS_ZIP */
@@ -88,7 +93,7 @@ struct erofs_sb_info {
 	u32 feature_compat;
 	u32 feature_incompat;
 
-	unsigned int mount_opt;
+	struct erofs_fs_context ctx;	/* options */
 };
 
 #define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
@@ -98,17 +103,17 @@ struct erofs_sb_info {
 #define EROFS_MOUNT_XATTR_USER		0x00000010
 #define EROFS_MOUNT_POSIX_ACL		0x00000020
 
-#define clear_opt(sbi, option)	((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
-#define set_opt(sbi, option)	((sbi)->mount_opt |= EROFS_MOUNT_##option)
-#define test_opt(sbi, option)	((sbi)->mount_opt & EROFS_MOUNT_##option)
+#define clear_opt(ctx, option)	((ctx)->mount_opt &= ~EROFS_MOUNT_##option)
+#define set_opt(ctx, option)	((ctx)->mount_opt |= EROFS_MOUNT_##option)
+#define test_opt(ctx, option)	((ctx)->mount_opt & EROFS_MOUNT_##option)
 
-#ifdef CONFIG_EROFS_FS_ZIP
 enum {
 	EROFS_ZIP_CACHE_DISABLED,
 	EROFS_ZIP_CACHE_READAHEAD,
 	EROFS_ZIP_CACHE_READAROUND
 };
 
+#ifdef CONFIG_EROFS_FS_ZIP
 #define EROFS_LOCKED_MAGIC     (INT_MIN | 0xE0F510CCL)
 
 /* basic unit of the workstation of a super_block */