On Wed, Dec 20, 2017 at 11:18 PM, Luis Henriques <lhenriques@xxxxxxxx> wrote:
> A cephfs-specific quota implementation has been available in the
> user-space fuse client for a while. This quota implementation allows an
> administrator to restrict the number of bytes and/or the number of files
> in a filesystem subtree. This quota implementation, however, is
> supported at the client-level only, which means that cooperation is
> required between different clients accessing the system.
>
> This obviously assumes that all clients are trusted entities and will
> respect the quotas, preventing users from exceeding the quota limits.
> Since the kernel client doesn't support quotas, it has not been possible
> to use it in a cluster where quotas are a requirement.
>
> This patchset is an RFC that adds kernel client support for cephfs
> quotas as it is currently implemented in the ceph fuse client. Note
> however that this patchset is not yet feature complete, as it only
> implements the max_files quota (max_bytes is still missing).
>
> ** Changes since v2 **
>
> Rework after review from Yan, Zheng:
>
> - Dropped patch 0001 ("ceph: add seqlock for snaprealm hierarchy change
> detection") and use mdsc->snap_rwsem for walking the snaprealm
> hierarchy instead of adding a seqlock. This means that patches 0003
> and 0004 needed to be reworked.
>
> - Added a NULL check in ceph_handle_quota() after the inode lookup with
> ceph_find_inode().
>
> ** Changes since v1 **
>
> Instead of trying to do a reverse path walk to find the "quota realm"
> for a given directory, this patchset is now using snaprealms. Thus, for
> testing it, a modified MDS is required:
>
> https://github.com/ukernel/ceph/tree/wip-cephfs-quota-realm
>
> This modified MDS creates a snaprealm when a quota is set in a
> directory. This means that a client needs only to walk up the snaprealm
> hierarchy to find a directory that has quotas instead of doing the full
> reverse path walking.
>
> Note however that this requires an extra patch that adds a seqlock (1st
> patch in series) to detect changes in the snaprealm hierarchy.
>
> Luis Henriques (3):
> ceph: quota: add initial infrastructure to support cephfs quotas
> ceph: quotas: support for ceph.quota.max_files
> ceph: quota: don't allow cross-quota renames
>
> fs/ceph/Makefile | 2 +-
> fs/ceph/dir.c | 16 ++++
> fs/ceph/file.c | 4 +-
> fs/ceph/inode.c | 6 ++
> fs/ceph/mds_client.c | 23 +++++
> fs/ceph/mds_client.h | 2 +
> fs/ceph/quota.c | 190 +++++++++++++++++++++++++++++++++++++
> fs/ceph/super.h | 10 ++
> fs/ceph/xattr.c | 44 +++++++++
> include/linux/ceph/ceph_features.h | 3 +-
> include/linux/ceph/ceph_fs.h | 17 ++++
> 11 files changed, 314 insertions(+), 3 deletions(-)
> create mode 100644 fs/ceph/quota.c
>
a few minor comments, otherwise this series looks good.
Regards
Yan, Zheng
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