[PATCH AUTOSEL 5.4 25/34] ceph: allow ceph.dir.rctime xattr to be updatable

Sasha Levin
2022-06-07T19:42:38Z

From: Venky Shankar <vshankar@redhat.com>

[ Upstream commit d7a2dc523085f8b8c60548ceedc696934aefeb0e ]

`rctime' has been a pain point in cephfs due to its buggy
nature - inconsistent values reported and those sorts.
Fixing rctime is non-trivial needing an overall redesign
of the entire nested statistics infrastructure.

As a workaround, PR

http://github.com/ceph/ceph/pull/37938

allows this extended attribute to be manually set. This allows
users to "fixup" inconsistent rctime values. While this sounds
messy, its probably the wisest approach allowing users/scripts
to workaround buggy rctime values.

The above PR enables Ceph MDS to allow manually setting
rctime extended attribute with the corresponding user-land
changes. We may as well allow the same to be done via kclient
for parity.

Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ceph/xattr.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index cb18ee637cb7..4bcf0226818d 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -316,6 +316,14 @@ static ssize_t ceph_vxattrcb_snap_btime(struct ceph_inode_info *ci, char *val,
}
#define XATTR_RSTAT_FIELD(_type, _name) \
XATTR_NAME_CEPH(_type, _name, VXATTR_FLAG_RSTAT)
+#define XATTR_RSTAT_FIELD_UPDATABLE(_type, _name) \
+ { \
+ .name = CEPH_XATTR_NAME(_type, _name), \
+ .name_size = sizeof (CEPH_XATTR_NAME(_type, _name)), \
+ .getxattr_cb = ceph_vxattrcb_ ## _type ## _ ## _name, \
+ .exists_cb = NULL, \
+ .flags = VXATTR_FLAG_RSTAT, \
+ }
#define XATTR_LAYOUT_FIELD(_type, _name, _field) \
{ \
.name = CEPH_XATTR_NAME2(_type, _name, _field), \
@@ -353,7 +361,7 @@ static struct ceph_vxattr ceph_dir_vxattrs[] = {
XATTR_RSTAT_FIELD(dir, rfiles),
XATTR_RSTAT_FIELD(dir, rsubdirs),
XATTR_RSTAT_FIELD(dir, rbytes),
- XATTR_RSTAT_FIELD(dir, rctime),
+ XATTR_RSTAT_FIELD_UPDATABLE(dir, rctime),
{
.name = "ceph.dir.pin",
.name_size = sizeof("ceph.dir.pin"),
--
2.35.1