[PATCH 6.1 035/162] btrfs: setup qstr from dentrys using fscrypt helper

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>

[ Upstream commit ab3c5c18e8fa3f8ea116016095d25adab466cd39 ]

Most places where we get a struct qstr, we are doing so from a dentry.
With fscrypt, the dentry's name may be encrypted on-disk, so fscrypt
provides a helper to convert a dentry name to the appropriate disk name
if necessary. Convert each of the dentry name accesses to use
fscrypt_setup_filename(), then convert the resulting fscrypt_name back
to an unencrypted qstr. This does not work for nokey names, but the
specific locations that could spawn nokey names are noted.

At present, since there are no encrypted directories, nothing goes down
the filename encryption paths.

Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 9af86694fd5d ("btrfs: file_remove_privs needs an exclusive lock in direct io write")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/ctree.h       |   3 +
 fs/btrfs/inode.c       | 192 +++++++++++++++++++++++++++++++----------
 fs/btrfs/transaction.c |  40 ++++++---
 fs/btrfs/tree-log.c    |  11 ++-
 4 files changed, 189 insertions(+), 57 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 6718cee57a94e..5120cea15b096 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -28,6 +28,7 @@
 #include <linux/refcount.h>
 #include <linux/crc32c.h>
 #include <linux/iomap.h>
+#include <linux/fscrypt.h>
 #include "extent-io-tree.h"
 #include "extent_io.h"
 #include "extent_map.h"
@@ -3396,6 +3397,8 @@ struct btrfs_new_inode_args {
 	 */
 	struct posix_acl *default_acl;
 	struct posix_acl *acl;
+	struct fscrypt_name fname;
+	struct qstr name;
 };
 int btrfs_new_inode_prepare(struct btrfs_new_inode_args *args,
 			    unsigned int *trans_num_items);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a5e61ad2ba696..b5224dbaa4165 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4415,28 +4415,41 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
 	struct btrfs_trans_handle *trans;
 	struct inode *inode = d_inode(dentry);
 	int ret;
+	struct fscrypt_name fname;
+	struct qstr name;
+
+	ret = fscrypt_setup_filename(dir, &dentry->d_name, 1, &fname);
+	if (ret)
+		return ret;
+	name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
+
+	/* This needs to handle no-key deletions later on */
 
 	trans = __unlink_start_trans(dir);
-	if (IS_ERR(trans))
-		return PTR_ERR(trans);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		goto fscrypt_free;
+	}
 
 	btrfs_record_unlink_dir(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
 			0);
 
 	ret = btrfs_unlink_inode(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
-				 &dentry->d_name);
+				 &name);
 	if (ret)
-		goto out;
+		goto end_trans;
 
 	if (inode->i_nlink == 0) {
 		ret = btrfs_orphan_add(trans, BTRFS_I(inode));
 		if (ret)
-			goto out;
+			goto end_trans;
 	}
 
-out:
+end_trans:
 	btrfs_end_transaction(trans);
 	btrfs_btree_balance_dirty(BTRFS_I(dir)->root->fs_info);
+fscrypt_free:
+	fscrypt_free_filename(&fname);
 	return ret;
 }
 
@@ -4449,11 +4462,19 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	struct extent_buffer *leaf;
 	struct btrfs_dir_item *di;
 	struct btrfs_key key;
-	const struct qstr *name = &dentry->d_name;
+	struct qstr name;
 	u64 index;
 	int ret;
 	u64 objectid;
 	u64 dir_ino = btrfs_ino(BTRFS_I(dir));
+	struct fscrypt_name fname;
+
+	ret = fscrypt_setup_filename(dir, &dentry->d_name, 1, &fname);
+	if (ret)
+		return ret;
+	name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
+
+	/* This needs to handle no-key deletions later on */
 
 	if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID) {
 		objectid = inode->root->root_key.objectid;
@@ -4461,14 +4482,17 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 		objectid = inode->location.objectid;
 	} else {
 		WARN_ON(1);
+		fscrypt_free_filename(&fname);
 		return -EINVAL;
 	}
 
 	path = btrfs_alloc_path();
-	if (!path)
-		return -ENOMEM;
+	if (!path) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
-	di = btrfs_lookup_dir_item(trans, root, path, dir_ino, name, -1);
+	di = btrfs_lookup_dir_item(trans, root, path, dir_ino, &name, -1);
 	if (IS_ERR_OR_NULL(di)) {
 		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;
@@ -4494,7 +4518,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	 * call btrfs_del_root_ref, and it _shouldn't_ fail.
 	 */
 	if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID) {
-		di = btrfs_search_dir_index_item(root, path, dir_ino, name);
+		di = btrfs_search_dir_index_item(root, path, dir_ino, &name);
 		if (IS_ERR_OR_NULL(di)) {
 			if (!di)
 				ret = -ENOENT;
@@ -4511,7 +4535,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 	} else {
 		ret = btrfs_del_root_ref(trans, objectid,
 					 root->root_key.objectid, dir_ino,
-					 &index, name);
+					 &index, &name);
 		if (ret) {
 			btrfs_abort_transaction(trans, ret);
 			goto out;
@@ -4524,7 +4548,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 
-	btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name->len * 2);
+	btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name.len * 2);
 	inode_inc_iversion(dir);
 	dir->i_mtime = current_time(dir);
 	dir->i_ctime = dir->i_mtime;
@@ -4533,6 +4557,7 @@ static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
 		btrfs_abort_transaction(trans, ret);
 out:
 	btrfs_free_path(path);
+	fscrypt_free_filename(&fname);
 	return ret;
 }
 
@@ -4796,6 +4821,8 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 	int err = 0;
 	struct btrfs_trans_handle *trans;
 	u64 last_unlink_trans;
+	struct fscrypt_name fname;
+	struct qstr name;
 
 	if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
 		return -ENOTEMPTY;
@@ -4808,9 +4835,18 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 		return btrfs_delete_subvolume(dir, dentry);
 	}
 
+	err = fscrypt_setup_filename(dir, &dentry->d_name, 1, &fname);
+	if (err)
+		return err;
+	name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
+
+	/* This needs to handle no-key deletions later on */
+
 	trans = __unlink_start_trans(dir);
-	if (IS_ERR(trans))
-		return PTR_ERR(trans);
+	if (IS_ERR(trans)) {
+		err = PTR_ERR(trans);
+		goto out_notrans;
+	}
 
 	if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
 		err = btrfs_unlink_subvol(trans, dir, dentry);
@@ -4825,7 +4861,7 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 
 	/* now the directory is empty */
 	err = btrfs_unlink_inode(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
-				 &dentry->d_name);
+				 &name);
 	if (!err) {
 		btrfs_i_size_write(BTRFS_I(inode), 0);
 		/*
@@ -4844,7 +4880,9 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 	}
 out:
 	btrfs_end_transaction(trans);
+out_notrans:
 	btrfs_btree_balance_dirty(fs_info);
+	fscrypt_free_filename(&fname);
 
 	return err;
 }
@@ -5525,18 +5563,27 @@ void btrfs_evict_inode(struct inode *inode)
 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 			       struct btrfs_key *location, u8 *type)
 {
-	const struct qstr *name = &dentry->d_name;
+	struct qstr name;
 	struct btrfs_dir_item *di;
 	struct btrfs_path *path;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
 	int ret = 0;
+	struct fscrypt_name fname;
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 
+	ret = fscrypt_setup_filename(dir, &dentry->d_name, 1, &fname);
+	if (ret)
+		goto out;
+
+	name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
+
+	/* This needs to handle no-key deletions later on */
+
 	di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
-				   name, 0);
+				   &name, 0);
 	if (IS_ERR_OR_NULL(di)) {
 		ret = di ? PTR_ERR(di) : -ENOENT;
 		goto out;
@@ -5548,12 +5595,13 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
 		ret = -EUCLEAN;
 		btrfs_warn(root->fs_info,
 "%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, location(%llu %u %llu))",
-			   __func__, name->name, btrfs_ino(BTRFS_I(dir)),
+			   __func__, name.name, btrfs_ino(BTRFS_I(dir)),
 			   location->objectid, location->type, location->offset);
 	}
 	if (!ret)
 		*type = btrfs_dir_type(path->nodes[0], di);
 out:
+	fscrypt_free_filename(&fname);
 	btrfs_free_path(path);
 	return ret;
 }
@@ -5576,6 +5624,14 @@ static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
 	struct btrfs_key key;
 	int ret;
 	int err = 0;
+	struct fscrypt_name fname;
+	struct qstr name;
+
+	ret = fscrypt_setup_filename(dir, &dentry->d_name, 0, &fname);
+	if (ret)
+		return ret;
+
+	name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
 
 	path = btrfs_alloc_path();
 	if (!path) {
@@ -5598,12 +5654,11 @@ static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
 	leaf = path->nodes[0];
 	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
 	if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)) ||
-	    btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
+	    btrfs_root_ref_name_len(leaf, ref) != name.len)
 		goto out;
 
-	ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
-				   (unsigned long)(ref + 1),
-				   dentry->d_name.len);
+	ret = memcmp_extent_buffer(leaf, name.name, (unsigned long)(ref + 1),
+				   name.len);
 	if (ret)
 		goto out;
 
@@ -5622,6 +5677,7 @@ static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
 	err = 0;
 out:
 	btrfs_free_path(path);
+	fscrypt_free_filename(&fname);
 	return err;
 }
 
@@ -6230,9 +6286,19 @@ int btrfs_new_inode_prepare(struct btrfs_new_inode_args *args,
 	struct inode *inode = args->inode;
 	int ret;
 
+	if (!args->orphan) {
+		ret = fscrypt_setup_filename(dir, &args->dentry->d_name, 0,
+					     &args->fname);
+		if (ret)
+			return ret;
+		args->name = (struct qstr)FSTR_TO_QSTR(&args->fname.disk_name);
+	}
+
 	ret = posix_acl_create(dir, &inode->i_mode, &args->default_acl, &args->acl);
-	if (ret)
+	if (ret) {
+		fscrypt_free_filename(&args->fname);
 		return ret;
+	}
 
 	/* 1 to add inode item */
 	*trans_num_items = 1;
@@ -6272,6 +6338,7 @@ void btrfs_new_inode_args_destroy(struct btrfs_new_inode_args *args)
 {
 	posix_acl_release(args->acl);
 	posix_acl_release(args->default_acl);
+	fscrypt_free_filename(&args->fname);
 }
 
 /*
@@ -6697,6 +6764,8 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	struct btrfs_root *root = BTRFS_I(dir)->root;
 	struct inode *inode = d_inode(old_dentry);
 	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+	struct fscrypt_name fname;
+	struct qstr name;
 	u64 index;
 	int err;
 	int drop_inode = 0;
@@ -6708,6 +6777,12 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	if (inode->i_nlink >= BTRFS_LINK_MAX)
 		return -EMLINK;
 
+	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &fname);
+	if (err)
+		goto fail;
+
+	name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
+
 	err = btrfs_set_inode_index(BTRFS_I(dir), &index);
 	if (err)
 		goto fail;
@@ -6734,7 +6809,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
 
 	err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
-			     &dentry->d_name, 1, index);
+			     &name, 1, index);
 
 	if (err) {
 		drop_inode = 1;
@@ -6758,6 +6833,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
 	}
 
 fail:
+	fscrypt_free_filename(&fname);
 	if (trans)
 		btrfs_end_transaction(trans);
 	if (drop_inode) {
@@ -9030,6 +9106,8 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	int ret;
 	int ret2;
 	bool need_abort = false;
+	struct fscrypt_name old_fname, new_fname;
+	struct qstr old_name, new_name;
 
 	/*
 	 * For non-subvolumes allow exchange only within one subvolume, in the
@@ -9041,6 +9119,19 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	     new_ino != BTRFS_FIRST_FREE_OBJECTID))
 		return -EXDEV;
 
+	ret = fscrypt_setup_filename(old_dir, &old_dentry->d_name, 0, &old_fname);
+	if (ret)
+		return ret;
+
+	ret = fscrypt_setup_filename(new_dir, &new_dentry->d_name, 0, &new_fname);
+	if (ret) {
+		fscrypt_free_filename(&old_fname);
+		return ret;
+	}
+
+	old_name = (struct qstr)FSTR_TO_QSTR(&old_fname.disk_name);
+	new_name = (struct qstr)FSTR_TO_QSTR(&new_fname.disk_name);
+
 	/* close the race window with snapshot create/destroy ioctl */
 	if (old_ino == BTRFS_FIRST_FREE_OBJECTID ||
 	    new_ino == BTRFS_FIRST_FREE_OBJECTID)
@@ -9108,8 +9199,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 		/* force full log commit if subvolume involved. */
 		btrfs_set_log_full_commit(trans);
 	} else {
-		ret = btrfs_insert_inode_ref(trans, dest, &new_dentry->d_name,
-					     old_ino,
+		ret = btrfs_insert_inode_ref(trans, dest, &new_name, old_ino,
 					     btrfs_ino(BTRFS_I(new_dir)),
 					     old_idx);
 		if (ret)
@@ -9122,8 +9212,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 		/* force full log commit if subvolume involved. */
 		btrfs_set_log_full_commit(trans);
 	} else {
-		ret = btrfs_insert_inode_ref(trans, root, &old_dentry->d_name,
-					     new_ino,
+		ret = btrfs_insert_inode_ref(trans, root, &old_name, new_ino,
 					     btrfs_ino(BTRFS_I(old_dir)),
 					     new_idx);
 		if (ret) {
@@ -9158,8 +9247,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	} else { /* src is an inode */
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(old_dir),
 					   BTRFS_I(old_dentry->d_inode),
-					   &old_dentry->d_name,
-					   &old_rename_ctx);
+					   &old_name, &old_rename_ctx);
 		if (!ret)
 			ret = btrfs_update_inode(trans, root, BTRFS_I(old_inode));
 	}
@@ -9174,8 +9262,7 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	} else { /* dest is an inode */
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(new_dir),
 					   BTRFS_I(new_dentry->d_inode),
-					   &new_dentry->d_name,
-					   &new_rename_ctx);
+					   &new_name, &new_rename_ctx);
 		if (!ret)
 			ret = btrfs_update_inode(trans, dest, BTRFS_I(new_inode));
 	}
@@ -9185,14 +9272,14 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
-			     &new_dentry->d_name, 0, old_idx);
+			     &new_name, 0, old_idx);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out_fail;
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(old_dir), BTRFS_I(new_inode),
-			     &old_dentry->d_name, 0, new_idx);
+			     &old_name, 0, new_idx);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out_fail;
@@ -9235,6 +9322,8 @@ static int btrfs_rename_exchange(struct inode *old_dir,
 	    old_ino == BTRFS_FIRST_FREE_OBJECTID)
 		up_read(&fs_info->subvol_sem);
 
+	fscrypt_free_filename(&new_fname);
+	fscrypt_free_filename(&old_fname);
 	return ret;
 }
 
@@ -9274,6 +9363,8 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 	int ret;
 	int ret2;
 	u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
+	struct fscrypt_name old_fname, new_fname;
+	struct qstr old_name, new_name;
 
 	if (btrfs_ino(BTRFS_I(new_dir)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
 		return -EPERM;
@@ -9290,21 +9381,32 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 	    new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
 		return -ENOTEMPTY;
 
+	ret = fscrypt_setup_filename(old_dir, &old_dentry->d_name, 0, &old_fname);
+	if (ret)
+		return ret;
+
+	ret = fscrypt_setup_filename(new_dir, &new_dentry->d_name, 0, &new_fname);
+	if (ret) {
+		fscrypt_free_filename(&old_fname);
+		return ret;
+	}
+
+	old_name = (struct qstr)FSTR_TO_QSTR(&old_fname.disk_name);
+	new_name = (struct qstr)FSTR_TO_QSTR(&new_fname.disk_name);
 
 	/* check for collisions, even if the  name isn't there */
-	ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
-					     &new_dentry->d_name);
+	ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino, &new_name);
 
 	if (ret) {
 		if (ret == -EEXIST) {
 			/* we shouldn't get
 			 * eexist without a new_inode */
 			if (WARN_ON(!new_inode)) {
-				return ret;
+				goto out_fscrypt_names;
 			}
 		} else {
 			/* maybe -EOVERFLOW */
-			return ret;
+			goto out_fscrypt_names;
 		}
 	}
 	ret = 0;
@@ -9387,8 +9489,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 		/* force full log commit if subvolume involved. */
 		btrfs_set_log_full_commit(trans);
 	} else {
-		ret = btrfs_insert_inode_ref(trans, dest, &new_dentry->d_name,
-					     old_ino,
+		ret = btrfs_insert_inode_ref(trans, dest, &new_name, old_ino,
 					     btrfs_ino(BTRFS_I(new_dir)), index);
 		if (ret)
 			goto out_fail;
@@ -9412,7 +9513,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 	} else {
 		ret = __btrfs_unlink_inode(trans, BTRFS_I(old_dir),
 					   BTRFS_I(d_inode(old_dentry)),
-					   &old_dentry->d_name, &rename_ctx);
+					   &old_name, &rename_ctx);
 		if (!ret)
 			ret = btrfs_update_inode(trans, root, BTRFS_I(old_inode));
 	}
@@ -9431,7 +9532,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 		} else {
 			ret = btrfs_unlink_inode(trans, BTRFS_I(new_dir),
 						 BTRFS_I(d_inode(new_dentry)),
-						 &new_dentry->d_name);
+						 &new_name);
 		}
 		if (!ret && new_inode->i_nlink == 0)
 			ret = btrfs_orphan_add(trans,
@@ -9443,7 +9544,7 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 	}
 
 	ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
-			     &new_dentry->d_name, 0, index);
+			     &new_name, 0, index);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out_fail;
@@ -9478,6 +9579,9 @@ static int btrfs_rename(struct user_namespace *mnt_userns,
 out_whiteout_inode:
 	if (flags & RENAME_WHITEOUT)
 		iput(whiteout_args.inode);
+out_fscrypt_names:
+	fscrypt_free_filename(&old_fname);
+	fscrypt_free_filename(&new_fname);
 	return ret;
 }
 
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index b0fe054c9f401..c8918bdf15ccd 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -6,6 +6,7 @@
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/sched/mm.h>
 #include <linux/writeback.h>
 #include <linux/pagemap.h>
 #include <linux/blkdev.h>
@@ -1627,10 +1628,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	struct btrfs_root *root = pending->root;
 	struct btrfs_root *parent_root;
 	struct btrfs_block_rsv *rsv;
-	struct inode *parent_inode;
+	struct inode *parent_inode = pending->dir;
 	struct btrfs_path *path;
 	struct btrfs_dir_item *dir_item;
-	struct dentry *dentry;
 	struct extent_buffer *tmp;
 	struct extent_buffer *old;
 	struct timespec64 cur_time;
@@ -1639,6 +1639,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	u64 index = 0;
 	u64 objectid;
 	u64 root_flags;
+	unsigned int nofs_flags;
+	struct fscrypt_name fname;
+	struct qstr name;
 
 	ASSERT(pending->path);
 	path = pending->path;
@@ -1646,9 +1649,23 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	ASSERT(pending->root_item);
 	new_root_item = pending->root_item;
 
+	/*
+	 * We're inside a transaction and must make sure that any potential
+	 * allocations with GFP_KERNEL in fscrypt won't recurse back to
+	 * filesystem.
+	 */
+	nofs_flags = memalloc_nofs_save();
+	pending->error = fscrypt_setup_filename(parent_inode,
+						&pending->dentry->d_name, 0,
+						&fname);
+	memalloc_nofs_restore(nofs_flags);
+	if (pending->error)
+		goto free_pending;
+	name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
+
 	pending->error = btrfs_get_free_objectid(tree_root, &objectid);
 	if (pending->error)
-		goto no_free_objectid;
+		goto free_fname;
 
 	/*
 	 * Make qgroup to skip current new snapshot's qgroupid, as it is
@@ -1677,8 +1694,6 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	trace_btrfs_space_reservation(fs_info, "transaction",
 				      trans->transid,
 				      trans->bytes_reserved, 1);
-	dentry = pending->dentry;
-	parent_inode = pending->dir;
 	parent_root = BTRFS_I(parent_inode)->root;
 	ret = record_root_in_trans(trans, parent_root, 0);
 	if (ret)
@@ -1694,7 +1709,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	/* check if there is a file/dir which has the same name. */
 	dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
 					 btrfs_ino(BTRFS_I(parent_inode)),
-					 &dentry->d_name, 0);
+					 &name, 0);
 	if (dir_item != NULL && !IS_ERR(dir_item)) {
 		pending->error = -EEXIST;
 		goto dir_item_existed;
@@ -1789,7 +1804,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	ret = btrfs_add_root_ref(trans, objectid,
 				 parent_root->root_key.objectid,
 				 btrfs_ino(BTRFS_I(parent_inode)), index,
-				 &dentry->d_name);
+				 &name);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto fail;
@@ -1821,9 +1836,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	if (ret < 0)
 		goto fail;
 
-	ret = btrfs_insert_dir_item(trans, &dentry->d_name,
-				    BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
-				    index);
+	ret = btrfs_insert_dir_item(trans, &name, BTRFS_I(parent_inode), &key,
+				    BTRFS_FT_DIR, index);
 	/* We have check then name at the beginning, so it is impossible. */
 	BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
 	if (ret) {
@@ -1832,7 +1846,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	}
 
 	btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
-					 dentry->d_name.len * 2);
+						  name.len * 2);
 	parent_inode->i_mtime = current_time(parent_inode);
 	parent_inode->i_ctime = parent_inode->i_mtime;
 	ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode));
@@ -1864,7 +1878,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	trans->bytes_reserved = 0;
 clear_skip_qgroup:
 	btrfs_clear_skip_qgroup(trans);
-no_free_objectid:
+free_fname:
+	fscrypt_free_filename(&fname);
+free_pending:
 	kfree(new_root_item);
 	pending->root_item = NULL;
 	btrfs_free_path(path);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 9f55e81acc0ef..25fd3f34b8f21 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -7471,9 +7471,16 @@ void btrfs_log_new_name(struct btrfs_trans_handle *trans,
 	if (old_dir && old_dir->logged_trans == trans->transid) {
 		struct btrfs_root *log = old_dir->root->log_root;
 		struct btrfs_path *path;
+		struct fscrypt_name fname;
+		struct qstr name;
 
 		ASSERT(old_dir_index >= BTRFS_DIR_START_INDEX);
 
+		ret = fscrypt_setup_filename(&old_dir->vfs_inode,
+					     &old_dentry->d_name, 0, &fname);
+		if (ret)
+			goto out;
+		name = (struct qstr)FSTR_TO_QSTR(&fname.disk_name);
 		/*
 		 * We have two inodes to update in the log, the old directory and
 		 * the inode that got renamed, so we must pin the log to prevent
@@ -7493,6 +7500,7 @@ void btrfs_log_new_name(struct btrfs_trans_handle *trans,
 		path = btrfs_alloc_path();
 		if (!path) {
 			ret = -ENOMEM;
+			fscrypt_free_filename(&fname);
 			goto out;
 		}
 
@@ -7508,7 +7516,7 @@ void btrfs_log_new_name(struct btrfs_trans_handle *trans,
 		 */
 		mutex_lock(&old_dir->log_mutex);
 		ret = del_logged_dentry(trans, log, path, btrfs_ino(old_dir),
-					&old_dentry->d_name, old_dir_index);
+					&name, old_dir_index);
 		if (ret > 0) {
 			/*
 			 * The dentry does not exist in the log, so record its
@@ -7522,6 +7530,7 @@ void btrfs_log_new_name(struct btrfs_trans_handle *trans,
 		mutex_unlock(&old_dir->log_mutex);
 
 		btrfs_free_path(path);
+		fscrypt_free_filename(&fname);
 		if (ret < 0)
 			goto out;
 	}
-- 
2.40.1