btrfs: reserve correct number of items for inode creation

The various inode creation code paths do not account for the compression
property, POSIX ACLs, or the parent inode item when starting a
transaction. Fix it by refactoring all of these code paths to use a new
function, btrfs_new_inode_prepare(), which computes the correct number
of items. To do so, it needs to know whether POSIX ACLs will be created,
so move the ACL creation into that function. To reduce the number of
arguments that need to be passed around for inode creation, define
struct btrfs_new_inode_args containing all of the relevant information.

btrfs_new_inode_prepare() will also be a good place to set up the
fscrypt context and encrypted filename in the future.

Reviewed-by: Sweet Tea Dorminy <[email protected]>
Signed-off-by: Omar Sandoval <[email protected]>
Signed-off-by: David Sterba <[email protected]>

fs/btrfs/acl.c

@@ -55,8 +55,8 @@ struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu)
 	return acl;
 }
 
-static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
-			   struct inode *inode, struct posix_acl *acl, int type)
+int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode,
+		    struct posix_acl *acl, int type)
 {
 	int ret, size = 0;
 	const char *name;
@@ -127,35 +127,3 @@ int btrfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		inode->i_mode = old_mode;
 	return ret;
 }
-
-int btrfs_init_acl(struct btrfs_trans_handle *trans,
-		   struct inode *inode, struct inode *dir)
-{
-	struct posix_acl *default_acl, *acl;
-	int ret = 0;
-
-	/* this happens with subvols */
-	if (!dir)
-		return 0;
-
-	ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
-	if (ret)
-		return ret;
-
-	if (default_acl) {
-		ret = __btrfs_set_acl(trans, inode, default_acl,
-				      ACL_TYPE_DEFAULT);
-		posix_acl_release(default_acl);
-	}
-
-	if (acl) {
-		if (!ret)
-			ret = __btrfs_set_acl(trans, inode, acl,
-					      ACL_TYPE_ACCESS);
-		posix_acl_release(acl);
-	}
-
-	if (!default_acl && !acl)
-		cache_no_acl(inode);
-	return ret;
-}

fs/btrfs/ctree.h

@@ -3284,11 +3284,32 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, long nr,
 int btrfs_set_extent_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
 			      unsigned int extra_bits,
 			      struct extent_state **cached_state);
+struct btrfs_new_inode_args {
+	/* Input */
+	struct inode *dir;
+	struct dentry *dentry;
+	struct inode *inode;
+	bool orphan;
+	bool subvol;
+
+	/*
+	 * Output from btrfs_new_inode_prepare(), input to
+	 * btrfs_create_new_inode().
+	 */
+	struct posix_acl *default_acl;
+	struct posix_acl *acl;
+};
+int btrfs_new_inode_prepare(struct btrfs_new_inode_args *args,
+			    unsigned int *trans_num_items);
+int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
+			   struct btrfs_new_inode_args *args,
+			   u64 *index);
+void btrfs_new_inode_args_destroy(struct btrfs_new_inode_args *args);
 struct inode *btrfs_new_subvol_inode(struct user_namespace *mnt_userns,
 				     struct inode *dir);
 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *parent_root,
-			     struct inode *inode);
+			     struct btrfs_new_inode_args *args);
  void btrfs_set_delalloc_extent(struct inode *inode, struct extent_state *state,
 			       unsigned *bits);
 void btrfs_clear_delalloc_extent(struct inode *inode,
@@ -3846,15 +3867,16 @@ static inline int __btrfs_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag)
 struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu);
 int btrfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 		  struct posix_acl *acl, int type);
-int btrfs_init_acl(struct btrfs_trans_handle *trans,
-		   struct inode *inode, struct inode *dir);
+int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode,
+		    struct posix_acl *acl, int type);
 #else
 #define btrfs_get_acl NULL
 #define btrfs_set_acl NULL
-static inline int btrfs_init_acl(struct btrfs_trans_handle *trans,
-				 struct inode *inode, struct inode *dir)
+static inline int __btrfs_set_acl(struct btrfs_trans_handle *trans,
+				  struct inode *inode, struct posix_acl *acl,
+				  int type)
 {
-	return 0;
+	return -EOPNOTSUPP;
 }
 #endif