[PATCH v2 14/17] btrfs: create and free extent fscrypt_infos

[Sweet Tea Dorminy <sweettea-kernel@xxxxxxxxxx>]

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. Add creation of fscrypt_infos for new extent_maps, and
freeing as appropriate.

Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@xxxxxxxxxx>
---
 fs/btrfs/extent_map.c | 8 ++++++++
 fs/btrfs/extent_map.h | 3 +++
 fs/btrfs/inode.c      | 8 ++++++++
 3 files changed, 19 insertions(+)

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 0cdb3e86f29b..4fa5f97559da 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -65,6 +65,8 @@ void free_extent_map(struct extent_map *em)
 	if (!em)
 		return;
 	if (refcount_dec_and_test(&em->refs)) {
+		if (em->fscrypt_info)
+			fscrypt_free_extent_info(&em->fscrypt_info);
 		WARN_ON(extent_map_in_tree(em));
 		WARN_ON(!list_empty(&em->list));
 		if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
@@ -207,6 +209,12 @@ 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);
 
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 35d27c756e08..3a1b66b1cedf 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -27,6 +27,8 @@ enum {
 	EXTENT_FLAG_FS_MAPPING,
 	/* This em is merged from two or more physically adjacent ems */
 	EXTENT_FLAG_MERGED,
+	/* This em has a fscrypt info */
+	EXTENT_FLAG_ENCRYPTED,
 };
 
 struct extent_map {
@@ -50,6 +52,7 @@ struct extent_map {
 	 */
 	u64 generation;
 	unsigned long flags;
+	struct fscrypt_info *fscrypt_info;
 	/* Used for chunk mappings, flag EXTENT_FLAG_FS_MAPPING must be set */
 	struct map_lookup *map_lookup;
 	refcount_t refs;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 40c2ec328730..b43fc253ecd1 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7460,6 +7460,14 @@ static struct extent_map *create_io_em(struct btrfs_inode *inode, u64 start,
 		em->compress_type = compress_type;
 	}
 
+	ret = fscrypt_prepare_new_extent(&inode->vfs_inode, &em->fscrypt_info);
+	if (ret < 0) {
+		free_extent_map(em);
+		return ERR_PTR(ret);
+	}
+	if (em->fscrypt_info)
+		set_bit(EXTENT_FLAG_ENCRYPTED, &em->flags);
+
 	ret = btrfs_replace_extent_map_range(inode, em, true);
 	if (ret) {
 		free_extent_map(em);
-- 
2.40.1