eCryptfs: Cleanup inode initialization code

The eCryptfs inode get, initialization, and dentry interposition code
has two separate paths. One is for when dentry interposition is needed
after doing things like a mkdir in the lower filesystem and the other
is needed after a lookup. Unlocking new inodes and doing a d_add() needs
to happen at different times, depending on which type of dentry
interposing is being done.

This patch cleans up the inode get and initialization code paths and
splits them up so that the locking and d_add() differences mentioned
above can be handled appropriately in a later patch.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Tested-by: David <david@unsolicited.net>

fs/ecryptfs/ecryptfs_kernel.h

@@ -628,9 +628,6 @@ struct ecryptfs_open_req {
 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 				 struct super_block *sb);
 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode);
-int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
-					struct dentry *lower_dentry,
-					struct inode *ecryptfs_dir_inode);
 int ecryptfs_decode_and_decrypt_filename(char **decrypted_name,
 					 size_t *decrypted_name_size,
 					 struct dentry *ecryptfs_dentry,

fs/ecryptfs/inode.c

@@ -58,85 +58,87 @@ static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
 	return 0;
 }
 
-static int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
+static int ecryptfs_inode_set(struct inode *inode, void *opaque)
 {
-	ecryptfs_set_inode_lower(inode, (struct inode *)lower_inode);
-	inode->i_ino = ((struct inode *)lower_inode)->i_ino;
+	struct inode *lower_inode = opaque;
+
+	ecryptfs_set_inode_lower(inode, lower_inode);
+	fsstack_copy_attr_all(inode, lower_inode);
+	/* i_size will be overwritten for encrypted regular files */
+	fsstack_copy_inode_size(inode, lower_inode);
+	inode->i_ino = lower_inode->i_ino;
 	inode->i_version++;
-	inode->i_op = &ecryptfs_main_iops;
-	inode->i_fop = &ecryptfs_main_fops;
 	inode->i_mapping->a_ops = &ecryptfs_aops;
+
+	if (S_ISLNK(inode->i_mode))
+		inode->i_op = &ecryptfs_symlink_iops;
+	else if (S_ISDIR(inode->i_mode))
+		inode->i_op = &ecryptfs_dir_iops;
+	else
+		inode->i_op = &ecryptfs_main_iops;
+
+	if (S_ISDIR(inode->i_mode))
+		inode->i_fop = &ecryptfs_dir_fops;
+	else if (special_file(inode->i_mode))
+		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+	else
+		inode->i_fop = &ecryptfs_main_fops;
+
 	return 0;
 }
 
-struct inode *ecryptfs_get_inode(struct inode *lower_inode,
-				 struct super_block *sb)
+static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
+					  struct super_block *sb)
 {
 	struct inode *inode;
-	int rc = 0;
 
-	if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
-		rc = -EXDEV;
-		goto out;
-	}
-	if (!igrab(lower_inode)) {
-		rc = -ESTALE;
-		goto out;
-	}
+	if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
+		return ERR_PTR(-EXDEV);
+	if (!igrab(lower_inode))
+		return ERR_PTR(-ESTALE);
 	inode = iget5_locked(sb, (unsigned long)lower_inode,
 			     ecryptfs_inode_test, ecryptfs_inode_set,
 			     lower_inode);
 	if (!inode) {
-		rc = -EACCES;
 		iput(lower_inode);
-		goto out;
+		return ERR_PTR(-EACCES);
 	}
-	if (inode->i_state & I_NEW)
-		unlock_new_inode(inode);
-	else
+	if (!(inode->i_state & I_NEW))
 		iput(lower_inode);
-	if (S_ISLNK(lower_inode->i_mode))
-		inode->i_op = &ecryptfs_symlink_iops;
-	else if (S_ISDIR(lower_inode->i_mode))
-		inode->i_op = &ecryptfs_dir_iops;
-	if (S_ISDIR(lower_inode->i_mode))
-		inode->i_fop = &ecryptfs_dir_fops;
-	if (special_file(lower_inode->i_mode))
-		init_special_inode(inode, lower_inode->i_mode,
-				   lower_inode->i_rdev);
-	fsstack_copy_attr_all(inode, lower_inode);
-	/* This size will be overwritten for real files w/ headers and
-	 * other metadata */
-	fsstack_copy_inode_size(inode, lower_inode);
+
+	return inode;
+}
+
+struct inode *ecryptfs_get_inode(struct inode *lower_inode,
+				 struct super_block *sb)
+{
+	struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
+
+	if (!IS_ERR(inode) && (inode->i_state & I_NEW))
+		unlock_new_inode(inode);
+
 	return inode;
-out:
-	return ERR_PTR(rc);
 }
 
-#define ECRYPTFS_INTERPOSE_FLAG_D_ADD                 0x00000001
 /**
  * ecryptfs_interpose
  * @lower_dentry: Existing dentry in the lower filesystem
  * @dentry: ecryptfs' dentry
  * @sb: ecryptfs's super_block
- * @flags: flags to govern behavior of interpose procedure
  *
  * Interposes upper and lower dentries.
  *
  * Returns zero on success; non-zero otherwise
  */
 static int ecryptfs_interpose(struct dentry *lower_dentry,
-			      struct dentry *dentry, struct super_block *sb,
-			      u32 flags)
+			      struct dentry *dentry, struct super_block *sb)
 {
-	struct inode *lower_inode = lower_dentry->d_inode;
-	struct inode *inode = ecryptfs_get_inode(lower_inode, sb);
+	struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
+
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
-	if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
-		d_add(dentry, inode);
-	else
-		d_instantiate(dentry, inode);
+	d_instantiate(dentry, inode);
+
 	return 0;
 }
 
@@ -218,7 +220,7 @@ ecryptfs_do_create(struct inode *directory_inode,
 		goto out_lock;
 	}
 	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
-				directory_inode->i_sb, 0);
+				directory_inode->i_sb);
 	if (rc) {
 		ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 		goto out_lock;
@@ -305,15 +307,15 @@ out:
 }
 
 /**
- * ecryptfs_lookup_and_interpose_lower - Perform a lookup
+ * ecryptfs_lookup_interpose - Dentry interposition for a lookup
  */
-int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
-					struct dentry *lower_dentry,
-					struct inode *ecryptfs_dir_inode)
+static int ecryptfs_lookup_interpose(struct dentry *ecryptfs_dentry,
+				     struct dentry *lower_dentry,
+				     struct inode *ecryptfs_dir_inode)
 {
 	struct dentry *lower_dir_dentry;
 	struct vfsmount *lower_mnt;
-	struct inode *lower_inode;
+	struct inode *inode, *lower_inode;
 	struct ecryptfs_crypt_stat *crypt_stat;
 	char *page_virt = NULL;
 	int put_lower = 0, rc = 0;
@@ -341,14 +343,16 @@ int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
 		d_add(ecryptfs_dentry, NULL);
 		goto out;
 	}
-	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
-				ecryptfs_dir_inode->i_sb,
-				ECRYPTFS_INTERPOSE_FLAG_D_ADD);
-	if (rc) {
+	inode = __ecryptfs_get_inode(lower_inode, ecryptfs_dir_inode->i_sb);
+	if (IS_ERR(inode)) {
+		rc = PTR_ERR(inode);
 		printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
 		       __func__, rc);
 		goto out;
 	}
+	if (inode->i_state & I_NEW)
+		unlock_new_inode(inode);
+	d_add(ecryptfs_dentry, inode);
 	if (S_ISDIR(lower_inode->i_mode))
 		goto out;
 	if (S_ISLNK(lower_inode->i_mode))
@@ -442,12 +446,12 @@ static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 		goto out_d_drop;
 	}
 	if (lower_dentry->d_inode)
-		goto lookup_and_interpose;
+		goto interpose;
 	mount_crypt_stat = &ecryptfs_superblock_to_private(
 				ecryptfs_dentry->d_sb)->mount_crypt_stat;
 	if (!(mount_crypt_stat
 	    && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
-		goto lookup_and_interpose;
+		goto interpose;
 	dput(lower_dentry);
 	rc = ecryptfs_encrypt_and_encode_filename(
 		&encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
@@ -470,9 +474,9 @@ static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 				encrypted_and_encoded_name);
 		goto out_d_drop;
 	}
-lookup_and_interpose:
-	rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
-						 ecryptfs_dir_inode);
+interpose:
+	rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
+				       ecryptfs_dir_inode);
 	goto out;
 out_d_drop:
 	d_drop(ecryptfs_dentry);
@@ -500,7 +504,7 @@ static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 		      lower_new_dentry);
 	if (rc || !lower_new_dentry->d_inode)
 		goto out_lock;
-	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
+	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 	if (rc)
 		goto out_lock;
 	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
@@ -567,7 +571,7 @@ static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 	kfree(encoded_symname);
 	if (rc || !lower_dentry->d_inode)
 		goto out_lock;
-	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 	if (rc)
 		goto out_lock;
 	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
@@ -591,7 +595,7 @@ static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 	rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 	if (rc || !lower_dentry->d_inode)
 		goto out;
-	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 	if (rc)
 		goto out;
 	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
@@ -639,7 +643,7 @@ ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 	rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 	if (rc || !lower_dentry->d_inode)
 		goto out;
-	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 	if (rc)
 		goto out;
 	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);