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ceph: eliminate session->s_gen_ttl_lock
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Turn s_cap_gen field into an atomic_t, and just rely on the fact that we
hold the s_mutex when changing the s_cap_ttl field.

Signed-off-by: Jeff Layton <[email protected]>
Reviewed-by: Luis Henriques <[email protected]>
Signed-off-by: Ilya Dryomov <[email protected]>
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@jtlayton @idryomov
jtlayton authored and idryomov committed Jun 28, 2021
1 parent 7e65624 commit 52d60f8
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Showing 5 changed files with 17 additions and 29 deletions.
15 changes: 6 additions & 9 deletions fs/ceph/caps.c
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Original file line number Diff line number Diff line change
Expand Up @@ -645,9 +645,7 @@ void ceph_add_cap(struct inode *inode,
dout("add_cap %p mds%d cap %llx %s seq %d\n", inode,
session->s_mds, cap_id, ceph_cap_string(issued), seq);

spin_lock(&session->s_gen_ttl_lock);
gen = session->s_cap_gen;
spin_unlock(&session->s_gen_ttl_lock);
gen = atomic_read(&session->s_cap_gen);

cap = __get_cap_for_mds(ci, mds);
if (!cap) {
Expand Down Expand Up @@ -785,10 +783,8 @@ static int __cap_is_valid(struct ceph_cap *cap)
unsigned long ttl;
u32 gen;

spin_lock(&cap->session->s_gen_ttl_lock);
gen = cap->session->s_cap_gen;
gen = atomic_read(&cap->session->s_cap_gen);
ttl = cap->session->s_cap_ttl;
spin_unlock(&cap->session->s_gen_ttl_lock);

if (cap->cap_gen < gen || time_after_eq(jiffies, ttl)) {
dout("__cap_is_valid %p cap %p issued %s "
Expand Down Expand Up @@ -1182,7 +1178,8 @@ void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release)
* s_cap_gen while session is in the reconnect state.
*/
if (queue_release &&
(!session->s_cap_reconnect || cap->cap_gen == session->s_cap_gen)) {
(!session->s_cap_reconnect ||
cap->cap_gen == atomic_read(&session->s_cap_gen))) {
cap->queue_release = 1;
if (removed) {
__ceph_queue_cap_release(session, cap);
Expand Down Expand Up @@ -3288,7 +3285,7 @@ static void handle_cap_grant(struct inode *inode,
u64 size = le64_to_cpu(grant->size);
u64 max_size = le64_to_cpu(grant->max_size);
unsigned char check_caps = 0;
bool was_stale = cap->cap_gen < session->s_cap_gen;
bool was_stale = cap->cap_gen < atomic_read(&session->s_cap_gen);
bool wake = false;
bool writeback = false;
bool queue_trunc = false;
Expand Down Expand Up @@ -3340,7 +3337,7 @@ static void handle_cap_grant(struct inode *inode,
}

/* side effects now are allowed */
cap->cap_gen = session->s_cap_gen;
cap->cap_gen = atomic_read(&session->s_cap_gen);
cap->seq = seq;

__check_cap_issue(ci, cap, newcaps);
Expand Down
4 changes: 1 addition & 3 deletions fs/ceph/dir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1548,10 +1548,8 @@ static bool __dentry_lease_is_valid(struct ceph_dentry_info *di)
u32 gen;
unsigned long ttl;

spin_lock(&session->s_gen_ttl_lock);
gen = session->s_cap_gen;
gen = atomic_read(&session->s_cap_gen);
ttl = session->s_cap_ttl;
spin_unlock(&session->s_gen_ttl_lock);

if (di->lease_gen == gen &&
time_before(jiffies, ttl) &&
Expand Down
4 changes: 2 additions & 2 deletions fs/ceph/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1124,7 +1124,7 @@ static void __update_dentry_lease(struct inode *dir, struct dentry *dentry,
return;
}

if (di->lease_gen == session->s_cap_gen &&
if (di->lease_gen == atomic_read(&session->s_cap_gen) &&
time_before(ttl, di->time))
return; /* we already have a newer lease. */

Expand All @@ -1135,7 +1135,7 @@ static void __update_dentry_lease(struct inode *dir, struct dentry *dentry,

if (!di->lease_session)
di->lease_session = ceph_get_mds_session(session);
di->lease_gen = session->s_cap_gen;
di->lease_gen = atomic_read(&session->s_cap_gen);
di->lease_seq = le32_to_cpu(lease->seq);
di->lease_renew_after = half_ttl;
di->lease_renew_from = 0;
Expand Down
17 changes: 6 additions & 11 deletions fs/ceph/mds_client.c
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Original file line number Diff line number Diff line change
Expand Up @@ -749,8 +749,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,

ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);

spin_lock_init(&s->s_gen_ttl_lock);
s->s_cap_gen = 1;
atomic_set(&s->s_cap_gen, 1);
s->s_cap_ttl = jiffies - 1;

spin_lock_init(&s->s_cap_lock);
Expand Down Expand Up @@ -1763,7 +1762,7 @@ static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
ci->i_requested_max_size = 0;
spin_unlock(&ci->i_ceph_lock);
} else if (ev == RENEWCAPS) {
if (cap->cap_gen < cap->session->s_cap_gen) {
if (cap->cap_gen < atomic_read(&cap->session->s_cap_gen)) {
/* mds did not re-issue stale cap */
spin_lock(&ci->i_ceph_lock);
cap->issued = cap->implemented = CEPH_CAP_PIN;
Expand Down Expand Up @@ -3501,10 +3500,8 @@ static void handle_session(struct ceph_mds_session *session,
case CEPH_SESSION_STALE:
pr_info("mds%d caps went stale, renewing\n",
session->s_mds);
spin_lock(&session->s_gen_ttl_lock);
session->s_cap_gen++;
atomic_inc(&session->s_cap_gen);
session->s_cap_ttl = jiffies - 1;
spin_unlock(&session->s_gen_ttl_lock);
send_renew_caps(mdsc, session);
break;

Expand Down Expand Up @@ -3773,7 +3770,7 @@ static int reconnect_caps_cb(struct inode *inode, struct ceph_cap *cap,
cap->seq = 0; /* reset cap seq */
cap->issue_seq = 0; /* and issue_seq */
cap->mseq = 0; /* and migrate_seq */
cap->cap_gen = cap->session->s_cap_gen;
cap->cap_gen = atomic_read(&cap->session->s_cap_gen);

/* These are lost when the session goes away */
if (S_ISDIR(inode->i_mode)) {
Expand Down Expand Up @@ -4013,9 +4010,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
dout("session %p state %s\n", session,
ceph_session_state_name(session->s_state));

spin_lock(&session->s_gen_ttl_lock);
session->s_cap_gen++;
spin_unlock(&session->s_gen_ttl_lock);
atomic_inc(&session->s_cap_gen);

spin_lock(&session->s_cap_lock);
/* don't know if session is readonly */
Expand Down Expand Up @@ -4346,7 +4341,7 @@ static void handle_lease(struct ceph_mds_client *mdsc,

case CEPH_MDS_LEASE_RENEW:
if (di->lease_session == session &&
di->lease_gen == session->s_cap_gen &&
di->lease_gen == atomic_read(&session->s_cap_gen) &&
di->lease_renew_from &&
di->lease_renew_after == 0) {
unsigned long duration =
Expand Down
6 changes: 2 additions & 4 deletions fs/ceph/mds_client.h
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Original file line number Diff line number Diff line change
Expand Up @@ -186,10 +186,8 @@ struct ceph_mds_session {

struct ceph_auth_handshake s_auth;

/* protected by s_gen_ttl_lock */
spinlock_t s_gen_ttl_lock;
u32 s_cap_gen; /* inc each time we get mds stale msg */
unsigned long s_cap_ttl; /* when session caps expire */
atomic_t s_cap_gen; /* inc each time we get mds stale msg */
unsigned long s_cap_ttl; /* when session caps expire. protected by s_mutex */

/* protected by s_cap_lock */
spinlock_t s_cap_lock;
Expand Down

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