Daniel Vacek <[email protected]> wrote: > From: Josef Bacik <[email protected]> > > The fscrypt encryption context will be stored as a new tree item type. > This gives us flexibility to include different things in the future. > > Also update the tree-checker to validate the new item type.
Hi everyone, I'm running the btrfs for-next branch, along with the encryption patch set through my AI review prompts: https://github.com/masoncl/review-prompts I'm working on some btrfs specific instructions, but hopefully these reviews are already useful. I've kept the headers to make it easier to double check that I'm actually replying to the right email, but please let me know if any parts of this are incorrect: commit 203bfb91a4db9c826fa7f72034c13a1810a1b605 Author: Josef Bacik <[email protected]> btrfs: add extent encryption context tree item type The fscrypt encryption context will be stored as a new tree item type. This gives us flexibility to include different things in the future. Also update the tree-checker to validate the new item type. > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 3c0db279f592e..639462164d089 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c [ ... ] > @@ -496,6 +503,60 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans, > args->extent_inserted = true; > } > > + if (first_ctx <= last_ctx) { > + int slot, nritems; > + > + btrfs_release_path(path); > + > + key.objectid = ino; > + key.type = BTRFS_FSCRYPT_CTX_KEY; > + key.offset = first_ctx; > + > + ret = btrfs_search_slot(trans, root, &key, path, modify_tree, > !!modify_tree); > + if (ret < 0) > + goto out_ctx; [ ... ] > +out_ctx: > + if (args->path && args->extent_inserted) { > + btrfs_release_path(path); > + > + key.objectid = ino; > + key.type = BTRFS_EXTENT_DATA_KEY; > + key.offset = args->start; > + ret = btrfs_search_slot(trans, root, &key, path, 0, 0); > + } > + } > + Can btrfs_search_slot() at line 556 overwrite an error that occurred earlier in the out_ctx path? If btrfs_search_slot() at line 515 fails and execution jumps to out_ctx, but args->path and args->extent_inserted are both true, the second btrfs_search_slot() call will overwrite the original error stored in ret. If this second search succeeds (returns 0 or >0), the function returns success to the caller despite the fscrypt context cleanup having failed. This could lead to inconsistent filesystem state where extent data was inserted but the corresponding fscrypt context items were not properly cleaned up. > diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c > index 9675dbcd78a3b..776901f297fea 100644 > --- a/fs/btrfs/tree-checker.c > +++ b/fs/btrfs/tree-checker.c [ ... ] > +static int check_fscrypt_context(struct extent_buffer *leaf, > + struct btrfs_key *key, int slot, > + struct btrfs_key *prev_key) > +{ > + u32 sectorsize = leaf->fs_info->sectorsize; > + u32 item_size = btrfs_item_size(leaf, slot); > + > + if (unlikely(!IS_ALIGNED(key->offset, sectorsize))) { > + file_extent_err(leaf, slot, > +"unaligned file_offset for encryption context, have %llu should be aligned > to %u", > + key->offset, sectorsize); > + return -EUCLEAN; > + } > + > + /* > + * Previous key must have the same key->objectid (ino). > + * It can be XATTR_ITEM, INODE_ITEM or just another EXTENT_DATA. > + * But if objectids mismatch, it means we have a missing > + * INODE_ITEM. > + */ This isn't a bug, but the comment says "It can be XATTR_ITEM, INODE_ITEM or just another EXTENT_DATA" - can EXTENT_DATA actually be the previous key type? For BTRFS_FSCRYPT_CTX_KEY (type=42), EXTENT_DATA (type=108) cannot be a previous key because keys are sorted by (objectid, type, offset) and 108 > 42. The correct previous key types would be: XATTR_ITEM, INODE_ITEM, FSCRYPT_INODE_CTX_KEY, or another FSCRYPT_CTX_KEY. > @@ -214,6 +248,7 @@ static int check_extent_data_item(struct extent_buffer > *leaf, > u32 item_size = btrfs_item_size(leaf, slot); > u64 extent_end; > u8 policy; > + u8 fe_type; > > if (unlikely(!IS_ALIGNED(key->offset, sectorsize))) { > file_extent_err(leaf, slot, [ ... ] > @@ -298,6 +333,19 @@ static int check_extent_data_item(struct extent_buffer > *leaf, > return 0; > } > > + if (policy == BTRFS_ENCRYPTION_FSCRYPT) { > + /* > + * Only regular and prealloc extents should have an encryption > + * context. > + */ > + if (unlikely(fe_type != BTRFS_FILE_EXTENT_REG && > + fe_type != BTRFS_FILE_EXTENT_PREALLOC)) { > + file_extent_err(leaf, slot, > + "invalid type for encrypted file extent, have %u", fe_type); > + return -EUCLEAN; > + } > + } Can this validation check detect encrypted inline extents? Looking at the function flow, inline extents (BTRFS_FILE_EXTENT_INLINE) are handled at lines 310-333 and return before reaching this check. If a corrupted filesystem has an encrypted inline extent, it would pass tree-checker validation. Should the encryption check be moved to also cover the inline extent path, or should inline extents explicitly reject BTRFS_ENCRYPTION_FSCRYPT?
