ext4: Fix potential truncate BUG due to i_prealloc_list being non-empty
We need to call ext4_discard_reservation() earlier in ext4_truncate(),
to avoid a BUG() in ext4_mb_return_to_preallocation(), which is called
(ultimately) by ext4_free_blocks(). So we must ditch the blocks on
i_prealloc_list before we start freeing the data blocks.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a1c7d76..2d54c822 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3494,6 +3494,9 @@
* modify the block allocation tree.
*/
down_write(&ei->i_data_sem);
+
+ ext4_discard_reservation(inode);
+
/*
* The orphan list entry will now protect us from any crash which
* occurs before the truncate completes, so it is now safe to propagate
@@ -3563,8 +3566,6 @@
;
}
- ext4_discard_reservation(inode);
-
up_write(&ei->i_data_sem);
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);