ext4: Fix potential truncate BUG due to i_prealloc_list being non-empty (b4df2030) · Commits · 戴 / test

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>

fs/ext4/inode.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -3494,6 +3494,9 @@ void ext4_truncate(struct inode *inode)
		* 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 @@ do_indirects:
		;
		}

		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);

Admin message