Re: [PATCH] mm/vmscan.c: drop all inode/dentry cache from LRU

[Theodore Ts'o]

On Fri, May 24, 2019 at 01:36:01PM +0530, Sahitya Tummala wrote:
> This is important for the scenario where FBE (file based encryption)
> is enabled. With FBE, the encryption context needed to en/decrypt a file
> will be stored in inode and any inode that is left in the cache after
> drop_caches is done will be a problem. For ex, in Android, drop_caches
> will be used when switching work profiles.
> 
> Signed-off-by: Sahitya Tummala <stummala@xxxxxxxxxxxxxx>

Instead of making a change to vmscan.c, it's probably better to
migrate to the new fscrypt key-management framework, which solves this
problem with an explicit FS_IOC_REMOVE_ENCRYPTION_KEY ioctl.  This
allows the system to remove all inodes that were made available via a
single key without having nuking all other inodes --- this would make
it much faster after a user logs out of ChromeOS, for example:

See:

	https://patchwork.kernel.org/patch/10952019/

							- Ted