vfs: pull ext4's double-i_mutex-locking into common code
We want to do this elsewhere as well.
Also catch any attempts to use it for directories (where this ordering
would conflict with ancestor-first directory ordering in lock_rename).
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Dave Chinner <david@fromorbit.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index a569d33..60589b6 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -130,7 +130,7 @@
/* Protect orig inodes against a truncate and make sure,
* that only 1 swap_inode_boot_loader is running. */
- ext4_inode_double_lock(inode, inode_bl);
+ lock_two_nondirectories(inode, inode_bl);
truncate_inode_pages(&inode->i_data, 0);
truncate_inode_pages(&inode_bl->i_data, 0);
@@ -205,7 +205,7 @@
ext4_inode_resume_unlocked_dio(inode);
ext4_inode_resume_unlocked_dio(inode_bl);
- ext4_inode_double_unlock(inode, inode_bl);
+ unlock_two_nondirectories(inode, inode_bl);
iput(inode_bl);