APPLIED: eCryptfs: Use notify_change for truncating lower inodes
On 02/16/2012 07:38 AM, Colin King wrote:
From: Colin Ian King<colin.king@canonical.com>
SRU Justification:
When truncating inodes in the lower filesystem, eCryptfs directly
invoked vmtruncate(). As Christoph Hellwig pointed out, vmtruncate() is
a filesystem helper function, but filesystems may need to do more than
just a call to vmtruncate(). eCryptfs needs to go through
notify_change()->setattr to ensure truncate works reliable without
corruption or leaking blocks on a variety of filesystems.
Fix: With this patch , lower inode truncation is moved out of
ecryptfs_truncate() and the function is renamed to truncate_upper().
truncate_upper() updates an iattr for the lower inode to indicate
if the lower inode needs to be truncated upon return.
ecryptfs_setattr() then calls notify_change(), using the updated iattr
for the lower inode, to complete the truncation.
Without the patch we risk corrupting or leaking blocks on the lower
filesystem.
Has been soak tested with a variety of ftruncate() soak tests and also
running a full kernel build on ecryptfs with a lower ext4 filesystem.
https://bugs.launchpad.net/bugs/451368
This is a backport of commit 5f3ef64f4da1c587cdcfaaac72311225b7df094c
Colin Ian King (1):
eCryptfs: Use notify_change for truncating lower inodes
APPLIED: eCryptfs: Use notify_change for truncating lower inodes
