Hi Eric, This supports the concurrent CephFS subvolume quarantine series. There’s no Fixes: tag since this isn't addressing an existing upstream regression.
The quarantine series adds checks to Ceph's ->get_link(). However, if an encrypted symlink target was cached prior to quarantine, the VFS bypasses that callback entirely when following or reading it. While the target data is still valid, access now needs to be denied. This patch adds an opt-out for symlink caching and enables it for Ceph, handling the encrypted-symlink case for the concurrent series without affecting other filesystems. On Thu, Oct 15, 2026 at 9:35 PM Eric Biggers <[email protected]> wrote: > > On Thu, Oct 15, 2026 at 05:46:24PM +0000, Alex Markuze wrote: > > fscrypt stores decrypted symlink targets in inode->i_link. The VFS can > > use this field without calling the filesystem's ->get_link() callback. > > The target can remain valid after the access policy changes. > > > > The CephFS subvolume quarantine series adds access checks to > > ->get_link(). Quarantine can revoke access after a target is cached. The > > VFS cache can bypass these checks. > > > > The no_symlink_cache option in fscrypt_operations gives filesystems > > control of this cache. It applies during target creation, lookup and > > getattr. With this option set, the helpers do not read or update > > ->i_link. The filesystem callback can then revalidate access. > > > > Uncached targets use the existing delayed-free callback. Each uncached > > lookup allocates a temporary buffer and decrypts or encodes the target. > > This lets Ceph reuse fscrypt's target validation and buffer ownership. > > > > The default setting keeps the current cache behavior for other > > filesystems. Ceph selects the option so cached targets cannot bypass its > > ->get_link() checks. > > > > Signed-off-by: Alex Markuze <[email protected]> > > This sounds like a bug fix? If so, which commit is it fixing? > > - Eric >
