From: Amir Goldstein <amir73il@gmail.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Jan Kara <jack@suse.cz>, Christian Brauner <brauner@kernel.org>,
linux-unionfs@vger.kernel.org
Subject: [PATCH v2 0/4] Report overlayfs file ids with fanotify
Date: Thu, 13 Jul 2023 15:03:40 +0300 [thread overview]
Message-ID: <20230713120344.1422468-1-amir73il@gmail.com> (raw)
Miklos,
This is the second part of the work to support fanotify reporting of
events with file ids on overlayfs. The fanotify_event_info_fid struct
reported with fanotify events has an object file handle and an fsid,
so fanotify requires that filesystems can encode file handles and have
a non-zero f_fsid.
The first part [1] that was merged to v6.5-rc1, relaxed the fanotify
requirements for filesystems to support reporting events with fid to
require only the ->encode_fh() export operation.
Patch 1 changes overlayfs export_operations to meet the new requirements
with the default overlay configurations (i.e. no need for nfs_export=on),
thus, allowing an fanotify watch with FAN_REPORT_FID on overlayfs.
There are LTS tests [2] for fanotify(FAN_REPORT_FID) + overlayfs.
Patches 2-4 are not strcitly needed to support reporting fanotify events
with fid, because overlayfs already reports a non-zero f_fsid, it's just
not a unique fsid. So before allowing to report events with overlayfs
fids, I wanted to fix overlayfs fsid to be more unique.
I wanted to implement a persistent and unique fsid for overlayfs.
I wanted it to be the default behavior, but needed to avoid breaking
applications that rely on an existing overlayfs fsid to persist.
I came up with a solution that is described in patch 4 (uuid=auto) that
meets all the requirement above.
There is an xfstest to test the persistent-unique fsid feature [3].
This patch set has been in overlayfs-next for soaking since v6.5-rc1.
If you have any reservations that we will not be able to resolve in time
for 6.6, especially regarding the on-disk format and backward compat,
we could also merge only patch 1 and leave the fsid patches for later.
Thanks,
Amir.
[1] https://lore.kernel.org/linux-fsdevel/20230425130105.2606684-1-amir73il@gmail.com/
[2] https://github.com/amir73il/ltp/commits/ovl_encode_fid
[3] https://github.com/amir73il/xfstests/commits/ovl_fsid
Amir Goldstein (4):
ovl: support encoding non-decodable file handles
ovl: add support for unique fsid per instance
ovl: store persistent uuid/fsid with uuid=on
ovl: auto generate uuid for new overlay filesystems
Documentation/filesystems/overlayfs.rst | 25 ++++++++++
fs/overlayfs/copy_up.c | 2 +-
fs/overlayfs/export.c | 26 ++++++++---
fs/overlayfs/inode.c | 2 +-
fs/overlayfs/namei.c | 5 +-
fs/overlayfs/overlayfs.h | 22 +++++++++
fs/overlayfs/ovl_entry.h | 3 +-
fs/overlayfs/params.c | 31 +++++++++++--
fs/overlayfs/super.c | 29 ++++++++++--
fs/overlayfs/util.c | 61 +++++++++++++++++++++++++
10 files changed, 186 insertions(+), 20 deletions(-)
--
2.34.1
next reply other threads:[~2023-07-13 12:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-13 12:03 Amir Goldstein [this message]
2023-07-13 12:03 ` [PATCH v2 1/4] ovl: support encoding non-decodable file handles Amir Goldstein
2023-07-13 12:03 ` [PATCH v2 2/4] ovl: add support for unique fsid per instance Amir Goldstein
2023-07-13 12:03 ` [PATCH v2 3/4] ovl: store persistent uuid/fsid with uuid=on Amir Goldstein
2023-07-13 12:03 ` [PATCH v2 4/4] ovl: auto generate uuid for new overlay filesystems Amir Goldstein
2023-08-11 9:44 ` [PATCH v2 0/4] Report overlayfs file ids with fanotify Amir Goldstein
2023-08-11 13:20 ` Miklos Szeredi
2023-08-11 13:32 ` Amir Goldstein
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