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>
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 2484c7e..671a74b 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -1013,10 +1013,11 @@
*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;