From ba3e77a4a22af018d2fe4d745902b2531ca82aba Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Fri, 9 Dec 2022 22:14:01 +0100 Subject: gfs2: Remove support for glock holder auto-demotion Remove the support for glock holder auto-demotion (commit dc732906c245 and folow-ups) as we are not planning to use this feature, and the additional code therefore only adds unnecessary complexity. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glock.c | 194 +++++++++++-------------------------------------------- fs/gfs2/glock.h | 20 ------ fs/gfs2/incore.h | 1 - 3 files changed, 36 insertions(+), 179 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index c32c25b4c37c..a4c15e86b1f5 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -206,12 +206,6 @@ static int demote_ok(const struct gfs2_glock *gl) if (gl->gl_state == LM_ST_UNLOCKED) return 0; - /* - * Note that demote_ok is used for the lru process of disposing of - * glocks. For this purpose, we don't care if the glock's holders - * have the HIF_MAY_DEMOTE flag set or not. If someone is using - * them, don't demote. - */ if (!list_empty(&gl->gl_holders)) return 0; if (glops->go_demote_ok) @@ -394,7 +388,7 @@ static void do_error(struct gfs2_glock *gl, const int ret) struct gfs2_holder *gh, *tmp; list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { - if (!test_bit(HIF_WAIT, &gh->gh_iflags)) + if (test_bit(HIF_HOLDER, &gh->gh_iflags)) continue; if (ret & LM_OUT_ERROR) gh->gh_error = -EIO; @@ -408,45 +402,6 @@ static void do_error(struct gfs2_glock *gl, const int ret) } } -/** - * demote_incompat_holders - demote incompatible demoteable holders - * @gl: the glock we want to promote - * @current_gh: the newly promoted holder - * - * We're passing the newly promoted holder in @current_gh, but actually, any of - * the strong holders would do. - */ -static void demote_incompat_holders(struct gfs2_glock *gl, - struct gfs2_holder *current_gh) -{ - struct gfs2_holder *gh, *tmp; - - /* - * Demote incompatible holders before we make ourselves eligible. - * (This holder may or may not allow auto-demoting, but we don't want - * to demote the new holder before it's even granted.) - */ - list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { - /* - * Since holders are at the front of the list, we stop when we - * find the first non-holder. - */ - if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) - return; - if (gh == current_gh) - continue; - if (test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags) && - !may_grant(gl, current_gh, gh)) { - /* - * We should not recurse into do_promote because - * __gfs2_glock_dq only calls handle_callback, - * gfs2_glock_add_to_lru and __gfs2_glock_queue_work. - */ - __gfs2_glock_dq(gh); - } - } -} - /** * find_first_holder - find the first "holder" gh * @gl: the glock @@ -465,26 +420,6 @@ static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl) return NULL; } -/** - * find_first_strong_holder - find the first non-demoteable holder - * @gl: the glock - * - * Find the first holder that doesn't have the HIF_MAY_DEMOTE flag set. - */ -static inline struct gfs2_holder * -find_first_strong_holder(struct gfs2_glock *gl) -{ - struct gfs2_holder *gh; - - list_for_each_entry(gh, &gl->gl_holders, gh_list) { - if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) - return NULL; - if (!test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags)) - return gh; - } - return NULL; -} - /* * gfs2_instantiate - Call the glops instantiate function * @gh: The glock holder @@ -541,9 +476,8 @@ done: static int do_promote(struct gfs2_glock *gl) { struct gfs2_holder *gh, *current_gh; - bool incompat_holders_demoted = false; - current_gh = find_first_strong_holder(gl); + current_gh = find_first_holder(gl); list_for_each_entry(gh, &gl->gl_holders, gh_list) { if (test_bit(HIF_HOLDER, &gh->gh_iflags)) continue; @@ -562,11 +496,8 @@ static int do_promote(struct gfs2_glock *gl) set_bit(HIF_HOLDER, &gh->gh_iflags); trace_gfs2_promote(gh); gfs2_holder_wake(gh); - if (!incompat_holders_demoted) { + if (!current_gh) current_gh = gh; - demote_incompat_holders(gl, current_gh); - incompat_holders_demoted = true; - } } return 0; } @@ -1538,7 +1469,7 @@ __acquires(&gl->gl_lockref.lock) if (test_bit(GLF_LOCK, &gl->gl_flags)) { struct gfs2_holder *current_gh; - current_gh = find_first_strong_holder(gl); + current_gh = find_first_holder(gl); try_futile = !may_grant(gl, current_gh, gh); } if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) @@ -1550,8 +1481,6 @@ __acquires(&gl->gl_lockref.lock) continue; if (gh->gh_gl->gl_ops->go_type == LM_TYPE_FLOCK) continue; - if (test_bit(HIF_MAY_DEMOTE, &gh2->gh_iflags)) - continue; if (!pid_is_meaningful(gh2)) continue; goto trap_recursive; @@ -1666,64 +1595,42 @@ static void __gfs2_glock_dq(struct gfs2_holder *gh) int fast_path = 0; /* - * This while loop is similar to function demote_incompat_holders: - * If the glock is due to be demoted (which may be from another node - * or even if this holder is GL_NOCACHE), the weak holders are - * demoted as well, allowing the glock to be demoted. + * If we're in the process of file system withdraw, we cannot just + * dequeue any glocks until our journal is recovered, lest we introduce + * file system corruption. We need two exceptions to this rule: We need + * to allow unlocking of nondisk glocks and the glock for our own + * journal that needs recovery. */ - while (gh) { - /* - * If we're in the process of file system withdraw, we cannot - * just dequeue any glocks until our journal is recovered, lest - * we introduce file system corruption. We need two exceptions - * to this rule: We need to allow unlocking of nondisk glocks - * and the glock for our own journal that needs recovery. - */ - if (test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags) && - glock_blocked_by_withdraw(gl) && - gh->gh_gl != sdp->sd_jinode_gl) { - sdp->sd_glock_dqs_held++; - spin_unlock(&gl->gl_lockref.lock); - might_sleep(); - wait_on_bit(&sdp->sd_flags, SDF_WITHDRAW_RECOVERY, - TASK_UNINTERRUPTIBLE); - spin_lock(&gl->gl_lockref.lock); - } + if (test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags) && + glock_blocked_by_withdraw(gl) && + gh->gh_gl != sdp->sd_jinode_gl) { + sdp->sd_glock_dqs_held++; + spin_unlock(&gl->gl_lockref.lock); + might_sleep(); + wait_on_bit(&sdp->sd_flags, SDF_WITHDRAW_RECOVERY, + TASK_UNINTERRUPTIBLE); + spin_lock(&gl->gl_lockref.lock); + } - /* - * This holder should not be cached, so mark it for demote. - * Note: this should be done before the check for needs_demote - * below. - */ - if (gh->gh_flags & GL_NOCACHE) - handle_callback(gl, LM_ST_UNLOCKED, 0, false); + /* + * This holder should not be cached, so mark it for demote. + * Note: this should be done before the check for needs_demote + * below. + */ + if (gh->gh_flags & GL_NOCACHE) + handle_callback(gl, LM_ST_UNLOCKED, 0, false); - list_del_init(&gh->gh_list); - clear_bit(HIF_HOLDER, &gh->gh_iflags); - trace_gfs2_glock_queue(gh, 0); + list_del_init(&gh->gh_list); + clear_bit(HIF_HOLDER, &gh->gh_iflags); + trace_gfs2_glock_queue(gh, 0); - /* - * If there hasn't been a demote request we are done. - * (Let the remaining holders, if any, keep holding it.) - */ - if (!needs_demote(gl)) { - if (list_empty(&gl->gl_holders)) - fast_path = 1; - break; - } - /* - * If we have another strong holder (we cannot auto-demote) - * we are done. It keeps holding it until it is done. - */ - if (find_first_strong_holder(gl)) - break; - - /* - * If we have a weak holder at the head of the list, it - * (and all others like it) must be auto-demoted. If there - * are no more weak holders, we exit the while loop. - */ - gh = find_first_holder(gl); + /* + * If there hasn't been a demote request we are done. + * (Let the remaining holders, if any, keep holding it.) + */ + if (!needs_demote(gl)) { + if (list_empty(&gl->gl_holders)) + fast_path = 1; } if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl)) @@ -1938,33 +1845,6 @@ void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state) if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags)) delay = gl->gl_hold_time; } - /* - * Note 1: We cannot call demote_incompat_holders from handle_callback - * or gfs2_set_demote due to recursion problems like: gfs2_glock_dq -> - * handle_callback -> demote_incompat_holders -> gfs2_glock_dq - * Plus, we only want to demote the holders if the request comes from - * a remote cluster node because local holder conflicts are resolved - * elsewhere. - * - * Note 2: if a remote node wants this glock in EX mode, lock_dlm will - * request that we set our state to UNLOCKED. Here we mock up a holder - * to make it look like someone wants the lock EX locally. Any SH - * and DF requests should be able to share the lock without demoting. - * - * Note 3: We only want to demote the demoteable holders when there - * are no more strong holders. The demoteable holders might as well - * keep the glock until the last strong holder is done with it. - */ - if (!find_first_strong_holder(gl)) { - struct gfs2_holder mock_gh = { - .gh_gl = gl, - .gh_state = (state == LM_ST_UNLOCKED) ? - LM_ST_EXCLUSIVE : state, - .gh_iflags = BIT(HIF_HOLDER) - }; - - demote_incompat_holders(gl, &mock_gh); - } handle_callback(gl, state, delay, true); __gfs2_glock_queue_work(gl, delay); spin_unlock(&gl->gl_lockref.lock); @@ -2356,8 +2236,6 @@ static const char *hflags2str(char *buf, u16 flags, unsigned long iflags) *p++ = 'H'; if (test_bit(HIF_WAIT, &iflags)) *p++ = 'W'; - if (test_bit(HIF_MAY_DEMOTE, &iflags)) - *p++ = 'D'; if (flags & GL_SKIP) *p++ = 's'; *p = 0; diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h index e4be9e4bc979..f37ac087e2c1 100644 --- a/fs/gfs2/glock.h +++ b/fs/gfs2/glock.h @@ -156,8 +156,6 @@ static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock * list_for_each_entry(gh, &gl->gl_holders, gh_list) { if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) break; - if (test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags)) - continue; if (gh->gh_owner_pid == pid) goto out; } @@ -308,24 +306,6 @@ static inline bool gfs2_holder_queued(struct gfs2_holder *gh) return !list_empty(&gh->gh_list); } -static inline void gfs2_holder_allow_demote(struct gfs2_holder *gh) -{ - struct gfs2_glock *gl = gh->gh_gl; - - spin_lock(&gl->gl_lockref.lock); - set_bit(HIF_MAY_DEMOTE, &gh->gh_iflags); - spin_unlock(&gl->gl_lockref.lock); -} - -static inline void gfs2_holder_disallow_demote(struct gfs2_holder *gh) -{ - struct gfs2_glock *gl = gh->gh_gl; - - spin_lock(&gl->gl_lockref.lock); - clear_bit(HIF_MAY_DEMOTE, &gh->gh_iflags); - spin_unlock(&gl->gl_lockref.lock); -} - extern void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation); extern bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation); diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h index d09d9892cd05..c26765080f28 100644 --- a/fs/gfs2/incore.h +++ b/fs/gfs2/incore.h @@ -252,7 +252,6 @@ struct gfs2_lkstats { enum { /* States */ - HIF_MAY_DEMOTE = 1, HIF_HOLDER = 6, /* Set for gh that "holds" the glock */ HIF_WAIT = 10, }; -- cgit v1.2.3