fscrypt: eliminate ->prepare_context() operation

The only use of the ->prepare_context() fscrypt operation was to allow
ext4 to evict inline data from the inode before ->set_context().
However, there is no reason why this cannot be done as simply the first
step in ->set_context(), and in fact it makes more sense to do it that
way because then the policy modes and flags get validated before any
real work is done.  Therefore, merge ext4_prepare_context() into
ext4_set_context(), and remove ->prepare_context().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

3 files changed, 4 insertions, 14 deletions

diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index 14b76da71269..4908906d54d5 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -33,17 +33,10 @@ static int create_encryption_context_from_policy(struct inode *inode,
                                 const struct fscrypt_policy *policy)
 {
         struct fscrypt_context ctx;
-        int res;
 
         if (!inode->i_sb->s_cop->set_context)
                 return -EOPNOTSUPP;
 
-        if (inode->i_sb->s_cop->prepare_context) {
-                res = inode->i_sb->s_cop->prepare_context(inode);
-                if (res)
-                        return res;
-        }
-
         ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
         memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
                                         FS_KEY_DESCRIPTOR_SIZE);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 2e03a0a88d92..a9448db1cf7e 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1120,17 +1120,16 @@ static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
                                  EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
 }
 
-static int ext4_prepare_context(struct inode *inode)
-{
-        return ext4_convert_inline_data(inode);
-}
-
 static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
                                                         void *fs_data)
 {
         handle_t *handle = fs_data;
         int res, res2, retries = 0;
 
+        res = ext4_convert_inline_data(inode);
+        if (res)
+                return res;
+
         /*
          * If a journal handle was specified, then the encryption context is
          * being set on a new inode via inheritance and is part of a larger
@@ -1196,7 +1195,6 @@ static unsigned ext4_max_namelen(struct inode *inode)
 static const struct fscrypt_operations ext4_cryptops = {
         .key_prefix             = "ext4:",
         .get_context            = ext4_get_context,
-        .prepare_context        = ext4_prepare_context,
         .set_context            = ext4_set_context,
         .dummy_context          = ext4_dummy_context,
         .is_encrypted           = ext4_encrypted_inode,
diff --git a/include/linux/fscrypt_common.h b/include/linux/fscrypt_common.h
index 547f81592ba1..10c1abfbac6c 100644
--- a/include/linux/fscrypt_common.h
+++ b/include/linux/fscrypt_common.h
@@ -87,7 +87,6 @@ struct fscrypt_operations {
         unsigned int flags;
         const char *key_prefix;
         int (*get_context)(struct inode *, void *, size_t);
-        int (*prepare_context)(struct inode *);
         int (*set_context)(struct inode *, const void *, size_t, void *);
         int (*dummy_context)(struct inode *);
         bool (*is_encrypted)(struct inode *);