ext4: use fscrypt_prepare_new_inode() and fscrypt_set_context()

Convert ext4 to use the new functions fscrypt_prepare_new_inode() and
fscrypt_set_context().  This avoids calling
fscrypt_get_encryption_info() from within a transaction, which can
deadlock because fscrypt_get_encryption_info() isn't GFP_NOFS-safe.

For more details about this problem, see the earlier patch
"fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()".

Link: https://lore.kernel.org/r/20200917041136.178600-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 0cc576005a923d823e66f57e7602eebcbe3b8165..698ca4a4db5f786c5f2a9d729d5738d30424ea4c 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -819,7 +819,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
        ext4_group_t i;
        ext4_group_t flex_group;
        struct ext4_group_info *grp;
-       int encrypt = 0;
+       bool encrypt = false;
 
        /* Cannot create files in a deleted directory */
        if (!dir || !dir->i_nlink)
@@ -831,24 +831,6 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
        if (unlikely(ext4_forced_shutdown(sbi)))
                return ERR_PTR(-EIO);
 
-       if ((IS_ENCRYPTED(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
-           (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
-           !(i_flags & EXT4_EA_INODE_FL)) {
-               err = fscrypt_get_encryption_info(dir);
-               if (err)
-                       return ERR_PTR(err);
-               if (!fscrypt_has_encryption_key(dir))
-                       return ERR_PTR(-ENOKEY);
-               encrypt = 1;
-       }
-
-       if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
-               ret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt);
-               if (ret2 < 0)
-                       return ERR_PTR(ret2);
-               nblocks += ret2;
-       }
-
        ngroups = ext4_get_groups_count(sb);
        trace_ext4_request_inode(dir, mode);
        inode = new_inode(sb);
@@ -878,10 +860,25 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
        else
                ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
 
+       if (!(i_flags & EXT4_EA_INODE_FL)) {
+               err = fscrypt_prepare_new_inode(dir, inode, &encrypt);
+               if (err)
+                       goto out;
+       }
+
        err = dquot_initialize(inode);
        if (err)
                goto out;
 
+       if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
+               ret2 = ext4_xattr_credits_for_new_inode(dir, mode, encrypt);
+               if (ret2 < 0) {
+                       err = ret2;
+                       goto out;
+               }
+               nblocks += ret2;
+       }
+
        if (!goal)
                goal = sbi->s_inode_goal;
 
@@ -1174,7 +1171,7 @@ got:
         * prevent its deduplication.
         */
        if (encrypt) {
-               err = fscrypt_inherit_context(dir, inode, handle, true);
+               err = fscrypt_set_context(inode, handle);
                if (err)
                        goto fail_free_drop;
        }