fs-verity: add inode and superblock fields

Analogous to fs/crypto/, add fields to the VFS inode and superblock for
use by the fs/verity/ support layer:

- ->s_vop: points to the fsverity_operations if the filesystem supports
  fs-verity, otherwise is NULL.

- ->i_verity_info: points to cached fs-verity information for the inode
  after someone opens it, otherwise is NULL.

- S_VERITY: bit in ->i_flags that identifies verity inodes, even when
  they haven't been opened yet and thus still have NULL ->i_verity_info.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 56b8e35..b3a0f5b 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -64,6 +64,8 @@ struct workqueue_struct;
 struct iov_iter;
 struct fscrypt_info;
 struct fscrypt_operations;
+struct fsverity_info;
+struct fsverity_operations;
 struct fs_context;
 struct fs_parameter_description;
 
@@ -723,6 +725,10 @@ struct inode {
        struct fscrypt_info     *i_crypt_info;
 #endif
 
+#ifdef CONFIG_FS_VERITY
+       struct fsverity_info    *i_verity_info;
+#endif
+
        void                    *i_private; /* fs or device private pointer */
 } __randomize_layout;
 
@@ -1428,6 +1434,9 @@ struct super_block {
 #ifdef CONFIG_FS_ENCRYPTION
        const struct fscrypt_operations *s_cop;
 #endif
+#ifdef CONFIG_FS_VERITY
+       const struct fsverity_operations *s_vop;
+#endif
        struct hlist_bl_head    s_roots;        /* alternate root dentries for NFS */
        struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
        struct block_device     *s_bdev;
@@ -1965,6 +1974,7 @@ struct super_operations {
 #endif
 #define S_ENCRYPTED    16384   /* Encrypted file (using fs/crypto/) */
 #define S_CASEFOLD     32768   /* Casefolded file */
+#define S_VERITY       65536   /* Verity file (using fs/verity/) */
 
 /*
  * Note that nosuid etc flags are inode-specific: setting some file-system
@@ -2006,6 +2016,7 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags
 #define IS_DAX(inode)          ((inode)->i_flags & S_DAX)
 #define IS_ENCRYPTED(inode)    ((inode)->i_flags & S_ENCRYPTED)
 #define IS_CASEFOLDED(inode)   ((inode)->i_flags & S_CASEFOLD)
+#define IS_VERITY(inode)       ((inode)->i_flags & S_VERITY)
 
 #define IS_WHITEOUT(inode)     (S_ISCHR(inode->i_mode) && \
                                 (inode)->i_rdev == WHITEOUT_DEV)