Commit 6e263146 authored Jul 27, 2014 by Dmitry Monakhov Committed by Theodore Ts'o Jul 27, 2014

ext4: fix incorrect locking in move_extent_per_page



If we have to copy data we must drop i_data_sem because of
get_blocks() will be called inside mext_page_mkuptodate(), but later we must
reacquire it again because we are about to change extent's tree

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

parent 29faed16

fs/ext4/move_extent.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1013,10 +1013,11 @@ move_extent_per_page(struct file o_filp, struct inode donor_inode,
		*err = -EBUSY;
		goto unlock_pages;
		}

		ext4_double_down_write_data_sem(orig_inode, donor_inode);
		replaced_count = mext_replace_branches(handle, orig_inode, donor_inode,
		orig_blk_offset,
		block_len_in_page, err);
		ext4_double_up_write_data_sem(orig_inode, donor_inode);
		if (*err) {
		if (replaced_count) {
		block_len_in_page = replaced_count;