Commit 02ce5316 authored by Eric Biggers's avatar Eric Biggers
Browse files

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: default avatarEric Biggers <ebiggers@google.com>
parent 177cc0e7

fs/ext4/ialloc.c

+17 −20
Original line number Diff line number Diff line
@@ -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;

	}

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