In order to notify extents when their info is part of a master key which
is going away, the fscrypt_info must have a backpointer to the extent
somehow. Similarly, if a fscrypt_info is owned by an extent, the info
must not have a pointer to an inode -- multiple inodes may reference a
extent, and the first inode to cause an extent's creation may have a
lifetime much shorter than the extent, so there is no inode pointer
safe to track in an extent-owned info. Therefore, this adds a new
pointer for extent-owned infos to track their extent and updates
fscrypt_setup_encryption_info() accordingly.
Since it's simple to track the piece of extent memory pointing to the
info, and for the extent to then go from such a pointer to the whole
extent via container_of(), we store that. Although some sort of generic
void * or some artificial fscrypt_extent embedded structure would also
work, those would require additional plumbing which doesn't seem
strictly required or clarifying.
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@xxxxxxxxxx>
---
fs/crypto/fscrypt_private.h | 6 ++++++
fs/crypto/keysetup.c | 6 +++++-
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 0c7b785f1d8c..dc45cd35391f 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -229,6 +229,12 @@ struct fscrypt_info {
/* Back-pointer to the inode, for infos owned by a specific inode */
struct inode *ci_inode;
+ /*
+ * Back-pointer to the info pointer in the extent, for infos owned
+ * by an extent
+ */
+ struct fscrypt_info **ci_info_ptr;
+
/* The superblock of the filesystem to which this fscrypt_info pertains */
struct super_block *ci_sb;
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index 04f01da900ca..c611e2613aa6 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -567,7 +567,11 @@ fscrypt_setup_encryption_info(struct inode *inode,
if (!crypt_info)
return -ENOMEM;
- crypt_info->ci_inode = inode;
+ if (fscrypt_uses_extent_encryption(inode))
+ crypt_info->ci_info_ptr = info_ptr;
+ else
+ crypt_info->ci_inode = inode;
+
crypt_info->ci_sb = inode->i_sb;
crypt_info->ci_policy = *policy;
memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
--
2.38.1
|