[RFC PATCH 09/19] btrfs: add btrfs.key property

[Mark Harmstone]

Signed-off-by: Mark Harmstone <m...@harmstone.com>
---
 fs/btrfs/btrfs_inode.h |  5 ++++
 fs/btrfs/ctree.h       |  1 +
 fs/btrfs/inode.c       |  1 +
 fs/btrfs/props.c       | 68 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 75 insertions(+)

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 97d91e55b70a..cf9f50bbe4ef 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -175,6 +175,11 @@ struct btrfs_inode {
         */
        unsigned defrag_compress;
 
+       /*
+        * Salt of preferred encryption key
+        */
+       u64 prop_key;
+
        struct btrfs_delayed_node *delayed_node;
 
        /* File creation time. */
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4bab57e01e21..a1368c5c1236 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1453,6 +1453,7 @@ do {                                                      
             \
 #define BTRFS_INODE_NOATIME            (1 << 9)
 #define BTRFS_INODE_DIRSYNC            (1 << 10)
 #define BTRFS_INODE_COMPRESS           (1 << 11)
+#define BTRFS_INODE_ENCRYPT            (1 << 12)
 
 #define BTRFS_INODE_ROOT_ITEM_INIT     (1 << 31)
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 9ea4c6f0352f..1d1084cf9289 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9167,6 +9167,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
        ei->runtime_flags = 0;
        ei->prop_compress = BTRFS_COMPRESS_NONE;
        ei->defrag_compress = BTRFS_COMPRESS_NONE;
+       ei->prop_key = 0;
 
        ei->delayed_node = NULL;
 
diff --git a/fs/btrfs/props.c b/fs/btrfs/props.c
index e57a4edc88c4..ebe04194acbd 100644
--- a/fs/btrfs/props.c
+++ b/fs/btrfs/props.c
@@ -29,6 +29,12 @@ static int prop_compression_apply(struct inode *inode,
                                  size_t len);
 static int prop_compression_extract(struct inode *inode, char *value);
 
+static int prop_key_validate(const char *value, size_t len);
+static int prop_key_apply(struct inode *inode,
+                         const char *value,
+                         size_t len);
+static int prop_key_extract(struct inode *inode, char *value);
+
 static struct prop_handler prop_handlers[] = {
        {
                .xattr_name = XATTR_BTRFS_PREFIX "compression",
@@ -37,6 +43,13 @@ static struct prop_handler prop_handlers[] = {
                .extract = prop_compression_extract,
                .inheritable = 1
        },
+       {
+               .xattr_name = XATTR_BTRFS_PREFIX "key",
+               .validate = prop_key_validate,
+               .apply = prop_key_apply,
+               .extract = prop_key_extract,
+               .inheritable = 1
+       },
 };
 
 void __init btrfs_props_init(void)
@@ -435,4 +448,59 @@ static int prop_compression_extract(struct inode *inode, 
char *value)
        return -EINVAL;
 }
 
+static int prop_key_validate(const char *value, size_t len)
+{
+       unsigned int i;
+
+       if (len != 16)
+               return -EINVAL;
+
+       for (i = 0; i < 16; i++) {
+               if (hex_to_bin(value[i]) == -1)
+                       return -EINVAL;
+       }
 
+       return 0;
+}
+
+static int prop_key_apply(struct inode *inode,
+                         const char *value,
+                         size_t len)
+{
+       u64 salt;
+
+       if (len == 0) {
+               BTRFS_I(inode)->flags &= ~BTRFS_INODE_ENCRYPT;
+               BTRFS_I(inode)->prop_key = 0;
+
+               return 0;
+       }
+
+       if (len != 16)
+               return -EINVAL;
+
+       if (hex2bin((u8 *)&salt, value, len / 2))
+               return -EINVAL;
+
+       salt = be64_to_cpu(salt);
+
+       BTRFS_I(inode)->flags |= BTRFS_INODE_ENCRYPT;
+       BTRFS_I(inode)->prop_key = salt;
+
+       return 0;
+}
+
+static int prop_key_extract(struct inode *inode, char *value)
+{
+       u64 salt;
+
+       if (BTRFS_I(inode)->prop_key == 0)
+               return -EINVAL;
+
+       salt = cpu_to_be64(BTRFS_I(inode)->prop_key);
+       bin2hex(value, &salt, sizeof(salt));
+
+       value[16] = 0;
+
+       return 0;
+}
-- 
2.19.2