diff mbox series

[v2,17/17] btrfs: save and load fscrypt extent contexts

Message ID d3849d039673b6583291c29c5d36140357e1f1dc.1689564024.git.sweettea-kernel@dorminy.me (mailing list archive)
State New, archived
Headers show
Series btrfs: add encryption feature | expand

Commit Message

Sweet Tea Dorminy July 17, 2023, 3:52 a.m. UTC
This change actually saves and loads the extent contexts created and
freed by the last change.

Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 fs/btrfs/file-item.c            | 21 ++++++++++++++++
 fs/btrfs/fscrypt.c              | 36 +++++++++++++++++++++++++++
 fs/btrfs/fscrypt.h              |  6 +++++
 fs/btrfs/inode.c                | 44 ++++++++++++++++++++++++++++++---
 fs/btrfs/tree-log.c             | 24 ++++++++++++++++--
 include/uapi/linux/btrfs_tree.h |  5 ++++
 6 files changed, 130 insertions(+), 6 deletions(-)

Comments

Josef Bacik July 17, 2023, 6:15 p.m. UTC | #1
On Sun, Jul 16, 2023 at 11:52:48PM -0400, Sweet Tea Dorminy wrote:
> This change actually saves and loads the extent contexts created and
> freed by the last change.
> 
> Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
> ---
>  fs/btrfs/file-item.c            | 21 ++++++++++++++++
>  fs/btrfs/fscrypt.c              | 36 +++++++++++++++++++++++++++
>  fs/btrfs/fscrypt.h              |  6 +++++
>  fs/btrfs/inode.c                | 44 ++++++++++++++++++++++++++++++---
>  fs/btrfs/tree-log.c             | 24 ++++++++++++++++--
>  include/uapi/linux/btrfs_tree.h |  5 ++++
>  6 files changed, 130 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> index 8095fc2e7ca1..ccc2d12faba3 100644
> --- a/fs/btrfs/file-item.c
> +++ b/fs/btrfs/file-item.c
> @@ -1302,6 +1302,27 @@ void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
>  
>  		ctxsize = btrfs_file_extent_ctxsize_from_item(leaf, path);
>  		ASSERT(ctxsize == btrfs_file_extent_encryption_ctxsize(leaf, fi));
> +
> +#ifdef CONFIG_FS_ENCRYPTION
> +		if (ctxsize) {
> +			u8 context[FSCRYPT_SET_CONTEXT_MAX_SIZE];
> +			int res;
> +			unsigned int nofs_flag;
> +
> +			read_extent_buffer(leaf, context,
> +					   (unsigned long)fi->fscrypt_context,
> +					   ctxsize);
> +			nofs_flag = memalloc_nofs_save();
> +			res = fscrypt_load_extent_info(&inode->vfs_inode,
> +						       context, ctxsize,
> +						       &em->fscrypt_info);
> +			memalloc_nofs_restore(nofs_flag);
> +			if (res)
> +				btrfs_err(fs_info,
> +					  "Unable to load fscrypt info: %d",
> +					   res);
> +		}
> +#endif /* CONFIG_FS_ENCRYPTION */
>  	} else if (type == BTRFS_FILE_EXTENT_INLINE) {
>  		em->block_start = EXTENT_MAP_INLINE;
>  		em->start = extent_start;
> diff --git a/fs/btrfs/fscrypt.c b/fs/btrfs/fscrypt.c
> index 6875108f4363..30dab7d06589 100644
> --- a/fs/btrfs/fscrypt.c
> +++ b/fs/btrfs/fscrypt.c
> @@ -166,6 +166,41 @@ static bool btrfs_fscrypt_empty_dir(struct inode *inode)
>  	return inode->i_size == BTRFS_EMPTY_DIR_SIZE;
>  }
>  
> +int btrfs_fscrypt_get_extent_info(const struct inode *inode,
> +				  u64 lblk_num,
> +				  struct fscrypt_info **info_ptr,
> +				  u64 *extent_offset,
> +				  u64 *extent_length)
> +{
> +	u64 offset = lblk_num << inode->i_blkbits;
> +	struct extent_map *em;
> +
> +	/* Since IO must be in progress on this extent, this must succeed */
> +	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, offset, PAGE_SIZE);
> +	if (!em)
> +		return -EINVAL;
> +
> +	if (em->block_start == EXTENT_MAP_HOLE) {
> +		btrfs_info(BTRFS_I(inode)->root->fs_info,
> +			   "extent context requested for block %llu of inode %lu without an extent",
> +			   lblk_num, inode->i_ino);
> +		free_extent_map(em);
> +		return -ENOENT;
> +	}
> +
> +	*info_ptr = em->fscrypt_info;
> +
> +	if (extent_offset)
> +		*extent_offset
> +			 = (offset - em->start) >> inode->i_blkbits;
> +
> +	if (extent_length)
> +		*extent_length = em->len >> inode->i_blkbits;
> +
> +	free_extent_map(em);
> +	return 0;
> +}
> +
>  static struct block_device **btrfs_fscrypt_get_devices(struct super_block *sb,
>  						       unsigned int *num_devs)
>  {
> @@ -206,6 +241,7 @@ const struct fscrypt_operations btrfs_fscrypt_ops = {
>  	.get_context = btrfs_fscrypt_get_context,
>  	.set_context = btrfs_fscrypt_set_context,
>  	.empty_dir = btrfs_fscrypt_empty_dir,
> +	.get_extent_info = btrfs_fscrypt_get_extent_info,
>  	.get_devices = btrfs_fscrypt_get_devices,
>  	.key_prefix = "btrfs:"
>  };
> diff --git a/fs/btrfs/fscrypt.h b/fs/btrfs/fscrypt.h
> index 2d405d54cbc7..1cab721a64e5 100644
> --- a/fs/btrfs/fscrypt.h
> +++ b/fs/btrfs/fscrypt.h
> @@ -50,6 +50,12 @@ static inline bool btrfs_fscrypt_match_name(struct fscrypt_name *fname,
>  }
>  #endif /* CONFIG_FS_ENCRYPTION */
>  
> +int btrfs_fscrypt_get_extent_info(const struct inode *inode,
> +				  u64 lblk_num,
> +				  struct fscrypt_info **info_ptr,
> +				  u64 *extent_offset,
> +				  u64 *extent_length);
> +
>  extern const struct fscrypt_operations btrfs_fscrypt_ops;
>  
>  #endif /* BTRFS_FSCRYPT_H */
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 83098779dad2..92a193785a21 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -3036,17 +3036,46 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
>  	u64 num_bytes = btrfs_stack_file_extent_num_bytes(stack_fi);
>  	u64 ram_bytes = btrfs_stack_file_extent_ram_bytes(stack_fi);
>  	struct btrfs_drop_extents_args drop_args = { 0 };
> -	size_t fscrypt_context_size =
> -		btrfs_stack_file_extent_encryption(stack_fi) ?
> -			FSCRYPT_SET_CONTEXT_MAX_SIZE : 0;
> +	size_t fscrypt_context_size = 0;
> +#ifdef CONFIG_FS_ENCRYPTION
> +	u8 context[FSCRYPT_SET_CONTEXT_MAX_SIZE];
> +#endif /* CONFIG_FS_ENCRYPTION */
> +
>  	int ret;
>  
>  	path = btrfs_alloc_path();
>  	if (!path)
>  		return -ENOMEM;
>  
> +#ifdef CONFIG_FS_ENCRYPTION
> +	if (IS_ENCRYPTED(&inode->vfs_inode)) {
> +		u8 encryption;
> +		struct fscrypt_info *fscrypt_info;
> +		u64 lblk_num = file_pos >> root->fs_info->sectorsize_bits;
> +
> +		ret = btrfs_fscrypt_get_extent_info(&inode->vfs_inode,
> +						    lblk_num, &fscrypt_info,
> +						    NULL, NULL);
> +		if (ret) {
> +			btrfs_err(root->fs_info, "No fscrypt context found");
> +			goto out;
> +		}
> +
> +		fscrypt_context_size =
> +			fscrypt_set_extent_context(fscrypt_info, context,
> +						   FSCRYPT_SET_CONTEXT_MAX_SIZE);
> +		if (fscrypt_context_size < 0) {
> +			ret = fscrypt_context_size;
> +			goto out;
> +		}
> +		encryption = btrfs_pack_encryption(BTRFS_ENCRYPTION_FSCRYPT,
> +						   fscrypt_context_size);
> +		btrfs_set_stack_file_extent_encryption(stack_fi, encryption);
> +	}
> +#endif /* CONFIG_FS_ENCRYPTION */

Make this into a helper so we're not cluttering the normal code path with the
ifdefs.

> +
>  	/*
> -	 * we may be replacing one extent in the tree with another.
> +	 * We may be replacing one extent in the tree with another.
>  	 * The new extent is pinned in the extent map, and we don't want
>  	 * to drop it from the cache until it is completely in the btree.
>  	 *
> @@ -3079,6 +3108,13 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
>  			btrfs_item_ptr_offset(leaf, path->slots[0]),
>  			sizeof(struct btrfs_file_extent_item));
>  
> +#ifdef CONFIG_FS_ENCRYPTION
> +	write_extent_buffer(leaf, context,
> +			    btrfs_item_ptr_offset(leaf, path->slots[0]) +
> +			    sizeof(struct btrfs_file_extent_item),
> +			    fscrypt_context_size);
> +#endif /* CONFIG_FS_ENCRYPTION */
> +
>  	btrfs_mark_buffer_dirty(leaf);
>  	btrfs_release_path(path);
>  
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 82c91097672b..f0ad281170c5 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -4634,8 +4634,22 @@ static int log_one_extent(struct btrfs_trans_handle *trans,
>  	u64 extent_offset = em->start - em->orig_start;
>  	u64 block_len;
>  	int ret;
> -	u8 encryption = btrfs_pack_encryption(IS_ENCRYPTED(&inode->vfs_inode) ?
> -					      BTRFS_ENCRYPTION_FSCRYPT : 0, 0);
> +	u8 encryption = 0;
> +	size_t fscrypt_context_size = 0;
> +#ifdef CONFIG_FS_ENCRYPTION
> +	u8 context[FSCRYPT_SET_CONTEXT_MAX_SIZE];
> +
> +	if (em->fscrypt_info) {
> +		fscrypt_context_size =
> +			fscrypt_set_extent_context(em->fscrypt_info, context,
> +						   FSCRYPT_SET_CONTEXT_MAX_SIZE);
> +		if (fscrypt_context_size < 0)
> +			return fscrypt_context_size;
> +
> +		encryption = btrfs_pack_encryption(BTRFS_ENCRYPTION_FSCRYPT,
> +						   fscrypt_context_size);
> +	}

Same here, looks like this can be it's own helper, and the code above can use
this helper and do the other thing it needs to.  Thanks,

Josef
diff mbox series

Patch

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 8095fc2e7ca1..ccc2d12faba3 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -1302,6 +1302,27 @@  void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 
 		ctxsize = btrfs_file_extent_ctxsize_from_item(leaf, path);
 		ASSERT(ctxsize == btrfs_file_extent_encryption_ctxsize(leaf, fi));
+
+#ifdef CONFIG_FS_ENCRYPTION
+		if (ctxsize) {
+			u8 context[FSCRYPT_SET_CONTEXT_MAX_SIZE];
+			int res;
+			unsigned int nofs_flag;
+
+			read_extent_buffer(leaf, context,
+					   (unsigned long)fi->fscrypt_context,
+					   ctxsize);
+			nofs_flag = memalloc_nofs_save();
+			res = fscrypt_load_extent_info(&inode->vfs_inode,
+						       context, ctxsize,
+						       &em->fscrypt_info);
+			memalloc_nofs_restore(nofs_flag);
+			if (res)
+				btrfs_err(fs_info,
+					  "Unable to load fscrypt info: %d",
+					   res);
+		}
+#endif /* CONFIG_FS_ENCRYPTION */
 	} else if (type == BTRFS_FILE_EXTENT_INLINE) {
 		em->block_start = EXTENT_MAP_INLINE;
 		em->start = extent_start;
diff --git a/fs/btrfs/fscrypt.c b/fs/btrfs/fscrypt.c
index 6875108f4363..30dab7d06589 100644
--- a/fs/btrfs/fscrypt.c
+++ b/fs/btrfs/fscrypt.c
@@ -166,6 +166,41 @@  static bool btrfs_fscrypt_empty_dir(struct inode *inode)
 	return inode->i_size == BTRFS_EMPTY_DIR_SIZE;
 }
 
+int btrfs_fscrypt_get_extent_info(const struct inode *inode,
+				  u64 lblk_num,
+				  struct fscrypt_info **info_ptr,
+				  u64 *extent_offset,
+				  u64 *extent_length)
+{
+	u64 offset = lblk_num << inode->i_blkbits;
+	struct extent_map *em;
+
+	/* Since IO must be in progress on this extent, this must succeed */
+	em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, offset, PAGE_SIZE);
+	if (!em)
+		return -EINVAL;
+
+	if (em->block_start == EXTENT_MAP_HOLE) {
+		btrfs_info(BTRFS_I(inode)->root->fs_info,
+			   "extent context requested for block %llu of inode %lu without an extent",
+			   lblk_num, inode->i_ino);
+		free_extent_map(em);
+		return -ENOENT;
+	}
+
+	*info_ptr = em->fscrypt_info;
+
+	if (extent_offset)
+		*extent_offset
+			 = (offset - em->start) >> inode->i_blkbits;
+
+	if (extent_length)
+		*extent_length = em->len >> inode->i_blkbits;
+
+	free_extent_map(em);
+	return 0;
+}
+
 static struct block_device **btrfs_fscrypt_get_devices(struct super_block *sb,
 						       unsigned int *num_devs)
 {
@@ -206,6 +241,7 @@  const struct fscrypt_operations btrfs_fscrypt_ops = {
 	.get_context = btrfs_fscrypt_get_context,
 	.set_context = btrfs_fscrypt_set_context,
 	.empty_dir = btrfs_fscrypt_empty_dir,
+	.get_extent_info = btrfs_fscrypt_get_extent_info,
 	.get_devices = btrfs_fscrypt_get_devices,
 	.key_prefix = "btrfs:"
 };
diff --git a/fs/btrfs/fscrypt.h b/fs/btrfs/fscrypt.h
index 2d405d54cbc7..1cab721a64e5 100644
--- a/fs/btrfs/fscrypt.h
+++ b/fs/btrfs/fscrypt.h
@@ -50,6 +50,12 @@  static inline bool btrfs_fscrypt_match_name(struct fscrypt_name *fname,
 }
 #endif /* CONFIG_FS_ENCRYPTION */
 
+int btrfs_fscrypt_get_extent_info(const struct inode *inode,
+				  u64 lblk_num,
+				  struct fscrypt_info **info_ptr,
+				  u64 *extent_offset,
+				  u64 *extent_length);
+
 extern const struct fscrypt_operations btrfs_fscrypt_ops;
 
 #endif /* BTRFS_FSCRYPT_H */
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 83098779dad2..92a193785a21 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3036,17 +3036,46 @@  static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 	u64 num_bytes = btrfs_stack_file_extent_num_bytes(stack_fi);
 	u64 ram_bytes = btrfs_stack_file_extent_ram_bytes(stack_fi);
 	struct btrfs_drop_extents_args drop_args = { 0 };
-	size_t fscrypt_context_size =
-		btrfs_stack_file_extent_encryption(stack_fi) ?
-			FSCRYPT_SET_CONTEXT_MAX_SIZE : 0;
+	size_t fscrypt_context_size = 0;
+#ifdef CONFIG_FS_ENCRYPTION
+	u8 context[FSCRYPT_SET_CONTEXT_MAX_SIZE];
+#endif /* CONFIG_FS_ENCRYPTION */
+
 	int ret;
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 
+#ifdef CONFIG_FS_ENCRYPTION
+	if (IS_ENCRYPTED(&inode->vfs_inode)) {
+		u8 encryption;
+		struct fscrypt_info *fscrypt_info;
+		u64 lblk_num = file_pos >> root->fs_info->sectorsize_bits;
+
+		ret = btrfs_fscrypt_get_extent_info(&inode->vfs_inode,
+						    lblk_num, &fscrypt_info,
+						    NULL, NULL);
+		if (ret) {
+			btrfs_err(root->fs_info, "No fscrypt context found");
+			goto out;
+		}
+
+		fscrypt_context_size =
+			fscrypt_set_extent_context(fscrypt_info, context,
+						   FSCRYPT_SET_CONTEXT_MAX_SIZE);
+		if (fscrypt_context_size < 0) {
+			ret = fscrypt_context_size;
+			goto out;
+		}
+		encryption = btrfs_pack_encryption(BTRFS_ENCRYPTION_FSCRYPT,
+						   fscrypt_context_size);
+		btrfs_set_stack_file_extent_encryption(stack_fi, encryption);
+	}
+#endif /* CONFIG_FS_ENCRYPTION */
+
 	/*
-	 * we may be replacing one extent in the tree with another.
+	 * We may be replacing one extent in the tree with another.
 	 * The new extent is pinned in the extent map, and we don't want
 	 * to drop it from the cache until it is completely in the btree.
 	 *
@@ -3079,6 +3108,13 @@  static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 			btrfs_item_ptr_offset(leaf, path->slots[0]),
 			sizeof(struct btrfs_file_extent_item));
 
+#ifdef CONFIG_FS_ENCRYPTION
+	write_extent_buffer(leaf, context,
+			    btrfs_item_ptr_offset(leaf, path->slots[0]) +
+			    sizeof(struct btrfs_file_extent_item),
+			    fscrypt_context_size);
+#endif /* CONFIG_FS_ENCRYPTION */
+
 	btrfs_mark_buffer_dirty(leaf);
 	btrfs_release_path(path);
 
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 82c91097672b..f0ad281170c5 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -4634,8 +4634,22 @@  static int log_one_extent(struct btrfs_trans_handle *trans,
 	u64 extent_offset = em->start - em->orig_start;
 	u64 block_len;
 	int ret;
-	u8 encryption = btrfs_pack_encryption(IS_ENCRYPTED(&inode->vfs_inode) ?
-					      BTRFS_ENCRYPTION_FSCRYPT : 0, 0);
+	u8 encryption = 0;
+	size_t fscrypt_context_size = 0;
+#ifdef CONFIG_FS_ENCRYPTION
+	u8 context[FSCRYPT_SET_CONTEXT_MAX_SIZE];
+
+	if (em->fscrypt_info) {
+		fscrypt_context_size =
+			fscrypt_set_extent_context(em->fscrypt_info, context,
+						   FSCRYPT_SET_CONTEXT_MAX_SIZE);
+		if (fscrypt_context_size < 0)
+			return fscrypt_context_size;
+
+		encryption = btrfs_pack_encryption(BTRFS_ENCRYPTION_FSCRYPT,
+						   fscrypt_context_size);
+	}
+#endif /* CONFIG_FS_ENCRYPTION */
 
 	btrfs_set_stack_file_extent_generation(&fi, trans->transid);
 	if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
@@ -4697,6 +4711,12 @@  static int log_one_extent(struct btrfs_trans_handle *trans,
 	write_extent_buffer(leaf, &fi,
 			    btrfs_item_ptr_offset(leaf, path->slots[0]),
 			    sizeof(fi));
+#ifdef CONFIG_FS_ENCRYPTION
+	write_extent_buffer(leaf, context,
+			    btrfs_item_ptr_offset(leaf, path->slots[0]) +
+			    sizeof(fi), fscrypt_context_size);
+#endif /* CONFIG_FS_ENCRYPTION */
+
 	btrfs_mark_buffer_dirty(leaf);
 
 	btrfs_release_path(path);
diff --git a/include/uapi/linux/btrfs_tree.h b/include/uapi/linux/btrfs_tree.h
index ea4903cfd926..efe44db8210a 100644
--- a/include/uapi/linux/btrfs_tree.h
+++ b/include/uapi/linux/btrfs_tree.h
@@ -1080,6 +1080,11 @@  struct btrfs_file_extent_item {
 	 * always reflects the size uncompressed and without encoding.
 	 */
 	__le64 num_bytes;
+	/*
+	 * fscrypt extent encryption context. Only present if extent is
+	 * encrypted (as per the encryption field).
+	 */
+	__u8 fscrypt_context[0];
 
 } __attribute__ ((__packed__));