ext4 crypto: use a jbd2 transaction when adding a crypto policy

Start a jbd2 transaction, and mark the inode dirty on the inode under
that transaction after setting the encrypt flag.  Otherwise if the
directory isn't modified after setting the crypto policy, the
encrypted flag might not survive the inode getting pushed out from
memory, or the the file system getting unmounted and remounted.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c
index 02c4e5df7afb92986d13116777194bda133857f9..a640ec2c4b134a16a3bb374872a57643f12f3e60 100644 (file)
--- a/fs/ext4/crypto_policy.c
+++ b/fs/ext4/crypto_policy.c
@@ -12,6 +12,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 
+#include "ext4_jbd2.h"
 #include "ext4.h"
 #include "xattr.h"
 
@@ -49,7 +50,8 @@ static int ext4_create_encryption_context_from_policy(
        struct inode *inode, const struct ext4_encryption_policy *policy)
 {
        struct ext4_encryption_context ctx;
-       int res = 0;
+       handle_t *handle;
+       int res, res2;
 
        res = ext4_convert_inline_data(inode);
        if (res)
@@ -78,11 +80,22 @@ static int ext4_create_encryption_context_from_policy(
        BUILD_BUG_ON(sizeof(ctx.nonce) != EXT4_KEY_DERIVATION_NONCE_SIZE);
        get_random_bytes(ctx.nonce, EXT4_KEY_DERIVATION_NONCE_SIZE);
 
+       handle = ext4_journal_start(inode, EXT4_HT_MISC,
+                                   ext4_jbd2_credits_xattr(inode));
+       if (IS_ERR(handle))
+               return PTR_ERR(handle);
        res = ext4_xattr_set(inode, EXT4_XATTR_INDEX_ENCRYPTION,
                             EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, &ctx,
                             sizeof(ctx), 0);
-       if (!res)
+       if (!res) {
                ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
+               res = ext4_mark_inode_dirty(handle, inode);
+               if (res)
+                       EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
+       }
+       res2 = ext4_journal_stop(handle);
+       if (!res)
+               res = res2;
        return res;
 }