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Commit e8238f9a authored by Dmitry Monakhov's avatar Dmitry Monakhov Committed by Theodore Ts'o
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ext4: fix incorrect lock ordering for ext4_ind_migrate 



existing locking ordering: journal-> i_data_sem, but
ext4_ind_migrate() grab locks in opposite order which may result in
deadlock.

Signed-off-by: default avatarDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 393d1d1d

fs/ext4/extents.c

+5 −7
Original line number Diff line number Diff line
@@ -4735,6 +4735,10 @@ int ext4_ind_migrate(struct inode *inode) 
	    (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))

		return -EINVAL;



	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);

	if (IS_ERR(handle))

		return PTR_ERR(handle);



	down_write(&EXT4_I(inode)->i_data_sem);

	ret = ext4_ext_check_inode(inode);

	if (ret)
@@ -4758,19 +4762,13 @@ int ext4_ind_migrate(struct inode *inode) 
		}

	}



	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);

	if (IS_ERR(handle)) {

		ret = PTR_ERR(handle);

		goto errout;

	}



	ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);

	memset(ei->i_data, 0, sizeof(ei->i_data));

	for (i=0; i < len; i++)

		ei->i_data[i] = cpu_to_le32(blk++);

	ext4_mark_inode_dirty(handle, inode);

	ext4_journal_stop(handle);

errout:

	ext4_journal_stop(handle);

	up_write(&EXT4_I(inode)->i_data_sem);

	return ret;

}