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Commit 9ddfc3dc authored by Jan Kara's avatar Jan Kara Committed by Theodore Ts'o
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ext4: Fix lock inversion in ext4_ext_truncate() 



We cannot call ext4_orphan_add() from under i_data_sem because that
causes a lock ordering violation between i_data_sem and and the
superblock lock.

Updated with Aneesh's locking order fix

Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarMingming Cao <cmm@us.ibm.com>
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent cf108bca

fs/ext4/extents.c

+4 −3
Original line number Diff line number Diff line
@@ -2768,6 +2768,9 @@ void ext4_ext_truncate(struct inode *inode) 
	if (inode->i_size & (sb->s_blocksize - 1))

		ext4_block_truncate_page(handle, mapping, inode->i_size);



	if (ext4_orphan_add(handle, inode))

		goto out_stop;



	down_write(&EXT4_I(inode)->i_data_sem);

	ext4_ext_invalidate_cache(inode);
@@ -2778,8 +2781,6 @@ void ext4_ext_truncate(struct inode *inode) 
	 * Probably we need not scan at all,

	 * because page truncation is enough.

	 */

	if (ext4_orphan_add(handle, inode))

		goto out_stop;



	/* we have to know where to truncate from in crash case */

	EXT4_I(inode)->i_disksize = inode->i_size;
@@ -2796,6 +2797,7 @@ void ext4_ext_truncate(struct inode *inode) 
		handle->h_sync = 1;



out_stop:

	up_write(&EXT4_I(inode)->i_data_sem);

	/*

	 * If this was a simple ftruncate() and the file will remain alive,

	 * then we need to clear up the orphan record which we created above.
@@ -2806,7 +2808,6 @@ void ext4_ext_truncate(struct inode *inode) 
	if (inode->i_nlink)

		ext4_orphan_del(handle, inode);



	up_write(&EXT4_I(inode)->i_data_sem);

	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);

	ext4_mark_inode_dirty(handle, inode);

	ext4_journal_stop(handle);