[PATCH v4 21/46] btrfs: add fscrypt_info and encryption_type to extent_map

[Josef Bacik <josef@toxicpanda.com>]

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

Each extent_map will end up with a pointer to its associated
fscrypt_info if any, which should have the same lifetime as the
extent_map. We are also going to need to track the encryption_type for
the file extent items.  Add the fscrypt_info to the extent_map, and the
subsequent code for transferring it in the split and merge cases, as
well as the code necessary to free them.  A future patch will add the
code to load them as appropriate.

Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/extent_map.c | 39 +++++++++++++++++++++++++++++++++++----
 fs/btrfs/extent_map.h |  2 ++
 fs/btrfs/file-item.c  |  1 +
 fs/btrfs/inode.c      |  1 +
 4 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 20d347fa6f8a..b87d26fe6785 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -59,6 +59,12 @@ struct extent_map *alloc_extent_map(void)
 	return em;
 }
 
+static void __free_extent_map(struct extent_map *em)
+{
+	fscrypt_put_extent_info(em->fscrypt_info);
+	kmem_cache_free(extent_map_cache, em);
+}
+
 /*
  * Drop the reference out on @em by one and free the structure if the reference
  * count hits zero.
@@ -70,7 +76,7 @@ void free_extent_map(struct extent_map *em)
 	if (refcount_dec_and_test(&em->refs)) {
 		WARN_ON(extent_map_in_tree(em));
 		WARN_ON(!list_empty(&em->list));
-		kmem_cache_free(extent_map_cache, em);
+		__free_extent_map(em);
 	}
 }
 
@@ -96,12 +102,24 @@ void free_extent_map_safe(struct extent_map_tree *tree,
 	if (!em)
 		return;
 
-	if (refcount_dec_and_test(&em->refs)) {
-		WARN_ON(extent_map_in_tree(em));
-		WARN_ON(!list_empty(&em->list));
+	if (!refcount_dec_and_test(&em->refs))
+		return;
+
+	WARN_ON(extent_map_in_tree(em));
+	WARN_ON(!list_empty(&em->list));
+
+	/*
+	 * We could take a lock freeing the fscrypt_info, so add this to the
+	 * list of freed_extents to be freed later.
+	 */
+	if (em->fscrypt_info) {
 		list_add_tail(&em->free_list, &tree->freed_extents);
 		set_bit(EXTENT_MAP_TREE_PENDING_FREES, &tree->flags);
+		return;
 	}
+
+	/* Nothing scary here, just free the object. */
+	__free_extent_map(em);
 }
 
 /*
@@ -274,6 +292,12 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next)
 	if (!list_empty(&prev->list) || !list_empty(&next->list))
 		return 0;
 
+	/*
+	 * Don't merge adjacent encrypted maps.
+	 */
+	if (prev->fscrypt_info || next->fscrypt_info)
+		return 0;
+
 	ASSERT(next->block_start != EXTENT_MAP_DELALLOC &&
 	       prev->block_start != EXTENT_MAP_DELALLOC);
 
@@ -840,6 +864,8 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
 			split->generation = gen;
 			split->flags = flags;
 			split->compress_type = em->compress_type;
+			split->fscrypt_info =
+				fscrypt_get_extent_info(em->fscrypt_info);
 			replace_extent_mapping(em_tree, em, split, modified);
 			free_extent_map(split);
 			split = split2;
@@ -881,6 +907,8 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
 				split->orig_block_len = 0;
 			}
 
+			split->fscrypt_info =
+				fscrypt_get_extent_info(em->fscrypt_info);
 			if (extent_map_in_tree(em)) {
 				replace_extent_mapping(em_tree, em, split,
 						       modified);
@@ -1043,6 +1071,7 @@ int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,
 	split_pre->flags = flags;
 	split_pre->compress_type = em->compress_type;
 	split_pre->generation = em->generation;
+	split_pre->fscrypt_info = fscrypt_get_extent_info(em->fscrypt_info);
 
 	replace_extent_mapping(em_tree, em, split_pre, 1);
 
@@ -1062,6 +1091,8 @@ int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,
 	split_mid->flags = flags;
 	split_mid->compress_type = em->compress_type;
 	split_mid->generation = em->generation;
+	split_mid->fscrypt_info = fscrypt_get_extent_info(em->fscrypt_info);
+
 	add_extent_mapping(em_tree, split_mid, 1);
 
 	/* Once for us */
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index fb8905f88f7c..e1075cadfd94 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -48,8 +48,10 @@ struct extent_map {
 	 */
 	u64 generation;
 	unsigned long flags;
+	struct fscrypt_extent_info *fscrypt_info;
 	refcount_t refs;
 	unsigned int compress_type;
+	unsigned int encryption_type;
 	struct list_head list;
 	struct list_head free_list;
 };
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 45cae356e89b..26f35c1baedc 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -1305,6 +1305,7 @@ void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 			if (type == BTRFS_FILE_EXTENT_PREALLOC)
 				set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
 		}
+		em->encryption_type = btrfs_file_extent_encryption(leaf, fi);
 	} else if (type == BTRFS_FILE_EXTENT_INLINE) {
 		em->block_start = EXTENT_MAP_INLINE;
 		em->start = extent_start;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f894f5b5e786..5b1aea9f5f46 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7373,6 +7373,7 @@ static struct extent_map *create_io_em(struct btrfs_inode *inode, u64 start,
 		set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 		em->compress_type = compress_type;
 	}
+	em->encryption_type = BTRFS_ENCRYPTION_NONE;
 
 	ret = btrfs_replace_extent_map_range(inode, em, true);
 	if (ret) {
-- 
2.41.0