From: Josef Bacik <josef@toxicpanda.com>

New extents for encrypted inodes must have a fscrypt_extent_info, which
has the necessary keys and does all the registration at the block layer
for them.  This is passed through all of the infrastructure we've
previously added to make sure the context gets saved properly with the
file extents.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Daniel Vacek <neelx@suse.com>
---

v5: https://lore.kernel.org/linux-btrfs/d8ab016d25f70c9365f508af1d8e0b9ab7c09d76.1706116485.git.josef@toxicpanda.com/
 * No changes since.
---
 fs/btrfs/inode.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 15191dffa354..de1989edffc1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7629,6 +7629,16 @@ struct extent_map *btrfs_create_io_em(struct btrfs_inode *inode, u64 start,
 	if (file_extent->fscrypt_info) {
 		btrfs_extent_map_set_encryption(em, BTRFS_ENCRYPTION_FSCRYPT);
 		em->fscrypt_info = fscrypt_get_extent_info(file_extent->fscrypt_info);
+	} else if (IS_ENCRYPTED(&inode->vfs_inode)) {
+		struct fscrypt_extent_info *fscrypt_info;
+
+		btrfs_extent_map_set_encryption(em, BTRFS_ENCRYPTION_FSCRYPT);
+		fscrypt_info = fscrypt_prepare_new_extent(&inode->vfs_inode);
+		if (IS_ERR(fscrypt_info)) {
+			btrfs_free_extent_map(em);
+			return ERR_CAST(fscrypt_info);
+		}
+		em->fscrypt_info = fscrypt_info;
 	} else {
 		btrfs_extent_map_set_encryption(em, BTRFS_ENCRYPTION_NONE);
 	}
@@ -9348,6 +9358,9 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
 	if (trans)
 		own_trans = false;
 	while (num_bytes > 0) {
+		struct fscrypt_extent_info *fscrypt_info = NULL;
+		int encryption_type = BTRFS_ENCRYPTION_NONE;
+
 		cur_bytes = min_t(u64, num_bytes, SZ_256M);
 		cur_bytes = max(cur_bytes, min_size);
 		/*
@@ -9362,6 +9375,17 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
 		if (ret)
 			break;
 
+		if (IS_ENCRYPTED(inode)) {
+			fscrypt_info = fscrypt_prepare_new_extent(inode);
+			if (IS_ERR(fscrypt_info)) {
+				btrfs_dec_block_group_reservations(fs_info, ins.objectid);
+				btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
+				ret = PTR_ERR(fscrypt_info);
+				break;
+			}
+			encryption_type = BTRFS_ENCRYPTION_FSCRYPT;
+		}
+
 		/*
 		 * We've reserved this space, and thus converted it from
 		 * ->bytes_may_use to ->bytes_reserved.  Any error that happens
@@ -9373,7 +9397,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
 
 		last_alloc = ins.offset;
 		trans = insert_prealloc_file_extent(trans, BTRFS_I(inode),
-						    &ins, NULL, cur_offset);
+						    &ins, fscrypt_info, cur_offset);
 		/*
 		 * Now that we inserted the prealloc extent we can finally
 		 * decrement the number of reservations in the block group.
@@ -9383,6 +9407,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
 		btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 		if (IS_ERR(trans)) {
 			ret = PTR_ERR(trans);
+			fscrypt_put_extent_info(fscrypt_info);
 			btrfs_free_reserved_extent(fs_info, ins.objectid,
 						   ins.offset, false);
 			break;
@@ -9390,6 +9415,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
 
 		em = btrfs_alloc_extent_map();
 		if (!em) {
+			fscrypt_put_extent_info(fscrypt_info);
 			btrfs_drop_extent_map_range(BTRFS_I(inode), cur_offset,
 					    cur_offset + ins.offset - 1, false);
 			btrfs_set_inode_full_sync(BTRFS_I(inode));
@@ -9404,6 +9430,8 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
 		em->ram_bytes = ins.offset;
 		em->flags |= EXTENT_FLAG_PREALLOC;
 		em->generation = trans->transid;
+		em->fscrypt_info = fscrypt_info;
+		btrfs_extent_map_set_encryption(em, encryption_type);
 
 		ret = btrfs_replace_extent_map_range(BTRFS_I(inode), em, true);
 		btrfs_free_extent_map(em);
-- 
2.51.0