Feature bits have to be encoded into the correct locations. This hasn't
been an issue so far because the only hole in the feature bits was in bit
10 (CEPHFS_FEATURE_RECLAIM_CLIENT), which is located in the 2nd byte. When
adding more bits that go beyond the this 2nd byte, the bug will show up.
Fixes: 9ba1e224538a ("ceph: allocate the correct amount of extra bytes for the session features")
Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
---
fs/ceph/mds_client.c | 7 +++++--
fs/ceph/mds_client.h | 2 --
2 files changed, 5 insertions(+), 4 deletions(-)
I hope I got this code right. I found this issue when trying to add an
extra feature bit that would go beyond bit 15 and that wasn't showing up
on the MDS side.
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 1bd3e1bb0fdf..77e742b6fd30 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1220,14 +1220,17 @@ static int encode_supported_features(void **p, void *end)
if (count > 0) {
size_t i;
size_t size = FEATURE_BYTES(count);
+ unsigned long bit;
if (WARN_ON_ONCE(*p + 4 + size > end))
return -ERANGE;
ceph_encode_32(p, size);
memset(*p, 0, size);
- for (i = 0; i < count; i++)
- ((unsigned char*)(*p))[i / 8] |= BIT(feature_bits[i] % 8);
+ for (i = 0; i < count; i++) {
+ bit = feature_bits[i];
+ ((unsigned char *)(*p))[bit / 8] |= BIT(bit % 8);
+ }
*p += size;
} else {
if (WARN_ON_ONCE(*p + 4 > end))
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 33497846e47e..12901e3a6823 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -45,8 +45,6 @@ enum ceph_feature_type {
CEPHFS_FEATURE_MULTI_RECONNECT, \
CEPHFS_FEATURE_DELEG_INO, \
CEPHFS_FEATURE_METRIC_COLLECT, \
- \
- CEPHFS_FEATURE_MAX, \
}
#define CEPHFS_FEATURES_CLIENT_REQUIRED {}
