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Commit b4df2030 authored by Theodore Ts'o's avatar Theodore Ts'o
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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: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent bf068ee2

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 @@ void ext4_truncate(struct inode *inode) 
		;

	}



	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);