-{
- schedule();
- return 0;
-}
-
-static void wait_on_holder(struct gfs2_holder *gh)
-{
- might_sleep();
- wait_on_bit(&gh->gh_iflags, HIF_WAIT, just_schedule, TASK_UNINTERRUPTIBLE);
-}
-
-static void gfs2_demote_wake(struct gfs2_glock *gl)
-{
- gl->gl_demote_state = LM_ST_EXCLUSIVE;
- clear_bit(GLF_DEMOTE, &gl->gl_flags);
- smp_mb__after_clear_bit();
- wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
-}
-
-static void wait_on_demote(struct gfs2_glock *gl)
-{
- might_sleep();
- wait_on_bit(&gl->gl_flags, GLF_DEMOTE, just_schedule, TASK_UNINTERRUPTIBLE);
-}
-
-/**
- * rq_mutex - process a mutex request in the queue
- * @gh: the glock holder
- *
- * Returns: 1 if the queue is blocked
- */
-
-static int rq_mutex(struct gfs2_holder *gh)
-{
- struct gfs2_glock *gl = gh->gh_gl;
-
- list_del_init(&gh->gh_list);
- /* gh->gh_error never examined. */
- set_bit(GLF_LOCK, &gl->gl_flags);
- clear_bit(HIF_WAIT, &gh->gh_iflags);
- smp_mb();
- wake_up_bit(&gh->gh_iflags, HIF_WAIT);
-
- return 1;
-}
-
-/**
- * rq_promote - process a promote request in the queue
- * @gh: the glock holder
- *
- * Acquire a new inter-node lock, or change a lock state to more restrictive.
- *
- * Returns: 1 if the queue is blocked
- */
-
-static int rq_promote(struct gfs2_holder *gh)
-{
- struct gfs2_glock *gl = gh->gh_gl;
-
- if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
- if (list_empty(&gl->gl_holders)) {
- gl->gl_req_gh = gh;
- set_bit(GLF_LOCK, &gl->gl_flags);
- spin_unlock(&gl->gl_spin);
- gfs2_glock_xmote_th(gh->gh_gl, gh);
- spin_lock(&gl->gl_spin);
- }
- return 1;
- }
-
- if (list_empty(&gl->gl_holders)) {
- set_bit(HIF_FIRST, &gh->gh_iflags);
- set_bit(GLF_LOCK, &gl->gl_flags);
- } else {
- struct gfs2_holder *next_gh;
- if (gh->gh_state == LM_ST_EXCLUSIVE)
- return 1;
- next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
- gh_list);
- if (next_gh->gh_state == LM_ST_EXCLUSIVE)
- return 1;
- }
-
- list_move_tail(&gh->gh_list, &gl->gl_holders);
- gh->gh_error = 0;
- set_bit(HIF_HOLDER, &gh->gh_iflags);
-
- gfs2_holder_wake(gh);
-
- return 0;
-}
-
-/**
- * rq_demote - process a demote request in the queue
- * @gh: the glock holder
- *
- * Returns: 1 if the queue is blocked
- */
-
-static int rq_demote(struct gfs2_glock *gl)
-{
- if (!list_empty(&gl->gl_holders))
- return 1;
-
- if (gl->gl_state == gl->gl_demote_state ||
- gl->gl_state == LM_ST_UNLOCKED) {
- gfs2_demote_wake(gl);
- return 0;
- }
-
- set_bit(GLF_LOCK, &gl->gl_flags);
- set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
-
- if (gl->gl_demote_state == LM_ST_UNLOCKED ||
- gl->gl_state != LM_ST_EXCLUSIVE) {
- spin_unlock(&gl->gl_spin);
- gfs2_glock_drop_th(gl);
- } else {
- spin_unlock(&gl->gl_spin);
- gfs2_glock_xmote_th(gl, NULL);
- }
-
- spin_lock(&gl->gl_spin);
- clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
-
- return 0;
-}
-
-/**
- * run_queue - process holder structures on a glock
- * @gl: the glock
- *
- */
-static void run_queue(struct gfs2_glock *gl)
-{
- struct gfs2_holder *gh;
- int blocked = 1;
-
- for (;;) {
- if (test_bit(GLF_LOCK, &gl->gl_flags))
- break;
-
- if (!list_empty(&gl->gl_waiters1)) {
- gh = list_entry(gl->gl_waiters1.next,
- struct gfs2_holder, gh_list);
- blocked = rq_mutex(gh);
- } else if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
- blocked = rq_demote(gl);
- if (test_bit(GLF_WAITERS2, &gl->gl_flags) &&
- !blocked) {
- set_bit(GLF_DEMOTE, &gl->gl_flags);
- gl->gl_demote_state = LM_ST_UNLOCKED;
- }
- clear_bit(GLF_WAITERS2, &gl->gl_flags);
- } else if (!list_empty(&gl->gl_waiters3)) {
- gh = list_entry(gl->gl_waiters3.next,
- struct gfs2_holder, gh_list);
- blocked = rq_promote(gh);
- } else
- break;
-
- if (blocked)
- break;
- }
-}
-
-/**
- * gfs2_glmutex_lock - acquire a local lock on a glock
- * @gl: the glock
- *
- * Gives caller exclusive access to manipulate a glock structure.
- */
-
-static void gfs2_glmutex_lock(struct gfs2_glock *gl)
-{
- spin_lock(&gl->gl_spin);
- if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
- struct gfs2_holder gh;
-
- gfs2_holder_init(gl, 0, 0, &gh);
- set_bit(HIF_WAIT, &gh.gh_iflags);
- list_add_tail(&gh.gh_list, &gl->gl_waiters1);
- spin_unlock(&gl->gl_spin);
- wait_on_holder(&gh);
- gfs2_holder_uninit(&gh);
- } else {
- gl->gl_owner_pid = get_pid(task_pid(current));
- gl->gl_ip = (unsigned long)__builtin_return_address(0);
- spin_unlock(&gl->gl_spin);
- }
-}
-
-/**
- * gfs2_glmutex_trylock - try to acquire a local lock on a glock
- * @gl: the glock
- *
- * Returns: 1 if the glock is acquired
- */
-
-static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
-{
- int acquired = 1;
-
- spin_lock(&gl->gl_spin);
- if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
- acquired = 0;
- } else {
- gl->gl_owner_pid = get_pid(task_pid(current));
- gl->gl_ip = (unsigned long)__builtin_return_address(0);
- }
- spin_unlock(&gl->gl_spin);
-
- return acquired;
-}
-
-/**
- * gfs2_glmutex_unlock - release a local lock on a glock
- * @gl: the glock
- *
- */
-
-static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
-{
- struct pid *pid;
-
- spin_lock(&gl->gl_spin);
- clear_bit(GLF_LOCK, &gl->gl_flags);
- pid = gl->gl_owner_pid;
- gl->gl_owner_pid = NULL;
- gl->gl_ip = 0;
- run_queue(gl);
- spin_unlock(&gl->gl_spin);
-
- put_pid(pid);
-}
-
-/**
- * handle_callback - process a demote request
- * @gl: the glock
- * @state: the state the caller wants us to change to
- *
- * There are only two requests that we are going to see in actual
- * practise: LM_ST_SHARED and LM_ST_UNLOCKED
- */
-
-static void handle_callback(struct gfs2_glock *gl, unsigned int state,
- int remote, unsigned long delay)
-{
- int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
-
- spin_lock(&gl->gl_spin);
- set_bit(bit, &gl->gl_flags);
- if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
- gl->gl_demote_state = state;
- gl->gl_demote_time = jiffies;
- if (remote && gl->gl_ops->go_type == LM_TYPE_IOPEN &&
- gl->gl_object) {
- gfs2_glock_schedule_for_reclaim(gl);
- spin_unlock(&gl->gl_spin);
- return;
- }
- } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
- gl->gl_demote_state != state) {
- if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
- set_bit(GLF_WAITERS2, &gl->gl_flags);
- else
- gl->gl_demote_state = LM_ST_UNLOCKED;
- }
- spin_unlock(&gl->gl_spin);
-}
-
-/**
- * state_change - record that the glock is now in a different state
- * @gl: the glock
- * @new_state the new state
- *
- */
-
-static void state_change(struct gfs2_glock *gl, unsigned int new_state)
-{
- int held1, held2;
-
- held1 = (gl->gl_state != LM_ST_UNLOCKED);
- held2 = (new_state != LM_ST_UNLOCKED);
-
- if (held1 != held2) {
- if (held2)
- gfs2_glock_hold(gl);
- else
- gfs2_glock_put(gl);
- }
-
- gl->gl_state = new_state;
- gl->gl_tchange = jiffies;
-}
-
-/**
- * drop_bh - Called after a lock module unlock completes
- * @gl: the glock
- * @ret: the return status
- *
- * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
- * Doesn't drop the reference on the glock the top half took out
- *
- */
-
-static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
-{
- struct gfs2_sbd *sdp = gl->gl_sbd;
- const struct gfs2_glock_operations *glops = gl->gl_ops;
-
- gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
- gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
- gfs2_assert_warn(sdp, !ret);
-
- state_change(gl, LM_ST_UNLOCKED);
-
- if (glops->go_inval)
- glops->go_inval(gl, DIO_METADATA);
-
- spin_lock(&gl->gl_spin);
- gfs2_demote_wake(gl);
- clear_bit(GLF_LOCK, &gl->gl_flags);
- spin_unlock(&gl->gl_spin);
- gfs2_glock_put(gl);
-}
-
-/**
- * xmote_bh - Called after the lock module is done acquiring a lock
- * @gl: The glock in question
- * @ret: the int returned from the lock module
- *
- */
-
-static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
-{
- struct gfs2_sbd *sdp = gl->gl_sbd;
- const struct gfs2_glock_operations *glops = gl->gl_ops;
- struct gfs2_holder *gh = gl->gl_req_gh;
- int prev_state = gl->gl_state;
- int op_done = 1;
-
- if (!gh && (ret & LM_OUT_ST_MASK) == LM_ST_UNLOCKED) {
- drop_bh(gl, ret);
- return;
- }
-
- gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
- gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
- gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
-
- state_change(gl, ret & LM_OUT_ST_MASK);
-
- if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
- if (glops->go_inval)
- glops->go_inval(gl, DIO_METADATA);
- } else if (gl->gl_state == LM_ST_DEFERRED) {
- /* We might not want to do this here.
- Look at moving to the inode glops. */
- if (glops->go_inval)
- glops->go_inval(gl, 0);
- }
-
- /* Deal with each possible exit condition */
-
- if (!gh) {
- gl->gl_stamp = jiffies;
- if (ret & LM_OUT_CANCELED) {
- op_done = 0;
- } else {
- spin_lock(&gl->gl_spin);
- if (gl->gl_state != gl->gl_demote_state) {
- spin_unlock(&gl->gl_spin);
- gfs2_glock_drop_th(gl);
- gfs2_glock_put(gl);
- return;
- }
- gfs2_demote_wake(gl);
- spin_unlock(&gl->gl_spin);
- }
- } else {
- spin_lock(&gl->gl_spin);
- list_del_init(&gh->gh_list);
- gh->gh_error = -EIO;
- if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
- goto out;
- gh->gh_error = GLR_CANCELED;
- if (ret & LM_OUT_CANCELED)
- goto out;
- if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
- list_add_tail(&gh->gh_list, &gl->gl_holders);
- gh->gh_error = 0;
- set_bit(HIF_HOLDER, &gh->gh_iflags);
- set_bit(HIF_FIRST, &gh->gh_iflags);
- op_done = 0;
- goto out;
- }
- gh->gh_error = GLR_TRYFAILED;
- if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
- goto out;
- gh->gh_error = -EINVAL;
- if (gfs2_assert_withdraw(sdp, 0) == -1)
- fs_err(sdp, "ret = 0x%.8X\n", ret);
-out:
- spin_unlock(&gl->gl_spin);
- }
-
- if (glops->go_xmote_bh)
- glops->go_xmote_bh(gl);
-
- if (op_done) {
- spin_lock(&gl->gl_spin);
- gl->gl_req_gh = NULL;
- clear_bit(GLF_LOCK, &gl->gl_flags);
- spin_unlock(&gl->gl_spin);
- }
-
- gfs2_glock_put(gl);
-
- if (gh)
- gfs2_holder_wake(gh);
-}
-
-static unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, void *lock,
- unsigned int cur_state, unsigned int req_state,
- unsigned int flags)
-{
- int ret = 0;
- if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
- ret = sdp->sd_lockstruct.ls_ops->lm_lock(lock, cur_state,
- req_state, flags);
- return ret;
-}
-
-/**
- * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
- * @gl: The glock in question
- * @state: the requested state
- * @flags: modifier flags to the lock call
- *
- */
-
-static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
-{
- struct gfs2_sbd *sdp = gl->gl_sbd;
- int flags = gh ? gh->gh_flags : 0;
- unsigned state = gh ? gh->gh_state : gl->gl_demote_state;
- const struct gfs2_glock_operations *glops = gl->gl_ops;
- int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
- LM_FLAG_NOEXP | LM_FLAG_ANY |
- LM_FLAG_PRIORITY);
- unsigned int lck_ret;
-
- if (glops->go_xmote_th)
- glops->go_xmote_th(gl);
-
- gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
- gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
- gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
- gfs2_assert_warn(sdp, state != gl->gl_state);
-
- gfs2_glock_hold(gl);
-
- lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
-
- if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
- return;
-
- if (lck_ret & LM_OUT_ASYNC)
- gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
- else
- xmote_bh(gl, lck_ret);
-}
-
-static unsigned int gfs2_lm_unlock(struct gfs2_sbd *sdp, void *lock,
- unsigned int cur_state)
-{
- int ret = 0;
- if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
- ret = sdp->sd_lockstruct.ls_ops->lm_unlock(lock, cur_state);
- return ret;
-}
-
-/**
- * gfs2_glock_drop_th - call into the lock module to unlock a lock
- * @gl: the glock
- *
- */
-
-static void gfs2_glock_drop_th(struct gfs2_glock *gl)
-{
- struct gfs2_sbd *sdp = gl->gl_sbd;
- const struct gfs2_glock_operations *glops = gl->gl_ops;
- unsigned int ret;
-
- if (glops->go_xmote_th)
- glops->go_xmote_th(gl);
-
- gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
- gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
- gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
-
- gfs2_glock_hold(gl);
-
- ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);