ceph: comment cleanups and clarifications
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 0874ac4..5027bbd 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1922,12 +1922,24 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
retry:
spin_lock(&ci->i_ceph_lock);
retry_locked:
+ /* Caps wanted by virtue of active open files. */
file_wanted = __ceph_caps_file_wanted(ci);
+
+ /* Caps which have active references against them */
used = __ceph_caps_used(ci);
+
+ /*
+ * "issued" represents the current caps that the MDS wants us to have.
+ * "implemented" is the set that we have been granted, and includes the
+ * ones that have not yet been returned to the MDS (the "revoking" set,
+ * usually because they have outstanding references).
+ */
issued = __ceph_caps_issued(ci, &implemented);
revoking = implemented & ~issued;
want = file_wanted;
+
+ /* The ones we currently want to retain (may be adjusted below) */
retain = file_wanted | used | CEPH_CAP_PIN;
if (!mdsc->stopping && inode->i_nlink > 0) {
if (file_wanted) {
@@ -2005,6 +2017,10 @@ void ceph_check_caps(struct ceph_inode_info *ci, int flags,
/* NOTE: no side-effects allowed, until we take s_mutex */
+ /*
+ * If we have an auth cap, we don't need to consider any
+ * overlapping caps as used.
+ */
cap_used = used;
if (ci->i_auth_cap && cap != ci->i_auth_cap)
cap_used &= ~ci->i_auth_cap->issued;
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 6588006..cbf8af4 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -393,7 +393,7 @@ struct ceph_mds_client {
struct ceph_mds_session **sessions; /* NULL for mds if no session */
atomic_t num_sessions;
- int max_sessions; /* len of s_mds_sessions */
+ int max_sessions; /* len of sessions array */
int stopping; /* true if shutting down */
atomic64_t quotarealms_count; /* # realms with quota */
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 5826948..482473e 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -160,7 +160,8 @@ struct ceph_cap {
int issued; /* latest, from the mds */
int implemented; /* implemented superset of
issued (for revocation) */
- int mds, mds_wanted;
+ int mds; /* mds index for this cap */
+ int mds_wanted; /* caps wanted from this mds */
};
/* caps to release */
struct {