Re: [PATCH] fscrypto: require write access to mount to set encryption policy

On Thu, Sep 08, 2016 at 02:20:38PM -0700, Eric Biggers wrote:

[To apply cleanly, my other two patches must be applied before this one]

Since setting an encryption policy requires writing metadata to the
filesystem, it should be guarded by mnt_want_write/mnt_drop_write.
Otherwise, a user could cause a write to a frozen or readonly
filesystem.  This was handled correctly by f2fs but not by ext4.  Make
fscrypt_process_policy() handle it rather than relying on the filesystem
to get it right.

Signed-off-by: Eric Biggers <redacted>
Cc: stable@vger.kernel.org # 4.1+; check fs/{ext4,f2fs}

Thanks, I have this in the ext4.git's fixes branch, but I plan to only
send the other two fixes to Linus, since (a) they are more critical,
and I'd prefer to get an Acked-by from Jaeguk or Changman (as the f2fs
maintainers) before I send this fix to Linus, since it touches f2fs.

Jaeguk, Changman, any objections?

							- Ted