diff options
Diffstat (limited to 'fs/gfs2/glock.c')
-rw-r--r-- | fs/gfs2/glock.c | 269 |
1 files changed, 99 insertions, 170 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index df335c258eb0..524f3c96b9a4 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -186,10 +186,11 @@ void gfs2_glock_free(struct gfs2_glock *gl) * */ -void gfs2_glock_hold(struct gfs2_glock *gl) +struct gfs2_glock *gfs2_glock_hold(struct gfs2_glock *gl) { GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref)); lockref_get(&gl->gl_lockref); + return gl; } /** @@ -205,12 +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) @@ -393,7 +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 +403,6 @@ 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 */ @@ -464,26 +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 @@ -540,9 +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; @@ -561,11 +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; } @@ -927,6 +859,48 @@ out_unlock: return; } +/** + * glock_set_object - set the gl_object field of a glock + * @gl: the glock + * @object: the object + */ +void glock_set_object(struct gfs2_glock *gl, void *object) +{ + void *prev_object; + + spin_lock(&gl->gl_lockref.lock); + prev_object = gl->gl_object; + gl->gl_object = object; + spin_unlock(&gl->gl_lockref.lock); + if (gfs2_assert_warn(gl->gl_name.ln_sbd, prev_object == NULL)) { + pr_warn("glock=%u/%llx\n", + gl->gl_name.ln_type, + (unsigned long long)gl->gl_name.ln_number); + gfs2_dump_glock(NULL, gl, true); + } +} + +/** + * glock_clear_object - clear the gl_object field of a glock + * @gl: the glock + */ +void glock_clear_object(struct gfs2_glock *gl, void *object) +{ + void *prev_object; + + spin_lock(&gl->gl_lockref.lock); + prev_object = gl->gl_object; + gl->gl_object = NULL; + spin_unlock(&gl->gl_lockref.lock); + if (gfs2_assert_warn(gl->gl_name.ln_sbd, + prev_object == object || prev_object == NULL)) { + pr_warn("glock=%u/%llx\n", + gl->gl_name.ln_type, + (unsigned long long)gl->gl_name.ln_number); + gfs2_dump_glock(NULL, gl, true); + } +} + void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation) { struct gfs2_inode_lvb *ri = (void *)gl->gl_lksb.sb_lvbptr; @@ -980,8 +954,6 @@ static bool gfs2_try_evict(struct gfs2_glock *gl) ip = NULL; spin_unlock(&gl->gl_lockref.lock); if (ip) { - struct gfs2_glock *inode_gl = NULL; - gl->gl_no_formal_ino = ip->i_no_formal_ino; set_bit(GIF_DEFERRED_DELETE, &ip->i_flags); d_prune_aliases(&ip->i_inode); @@ -991,14 +963,14 @@ static bool gfs2_try_evict(struct gfs2_glock *gl) spin_lock(&gl->gl_lockref.lock); ip = gl->gl_object; if (ip) { - inode_gl = ip->i_gl; - lockref_get(&inode_gl->gl_lockref); clear_bit(GIF_DEFERRED_DELETE, &ip->i_flags); + if (!igrab(&ip->i_inode)) + ip = NULL; } spin_unlock(&gl->gl_lockref.lock); - if (inode_gl) { - gfs2_glock_poke(inode_gl); - gfs2_glock_put(inode_gl); + if (ip) { + gfs2_glock_poke(ip->i_gl); + iput(&ip->i_inode); } evicted = !ip; } @@ -1039,6 +1011,7 @@ static void delete_work_func(struct work_struct *work) if (gfs2_queue_delete_work(gl, 5 * HZ)) return; } + goto out; } inode = gfs2_lookup_by_inum(sdp, no_addr, gl->gl_no_formal_ino, @@ -1051,6 +1024,7 @@ static void delete_work_func(struct work_struct *work) d_prune_aliases(inode); iput(inode); } +out: gfs2_glock_put(gl); } @@ -1256,13 +1230,12 @@ void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags, struct gfs2_holder *gh, unsigned long ip) { INIT_LIST_HEAD(&gh->gh_list); - gh->gh_gl = gl; + gh->gh_gl = gfs2_glock_hold(gl); gh->gh_ip = ip; gh->gh_owner_pid = get_pid(task_pid(current)); gh->gh_state = state; gh->gh_flags = flags; gh->gh_iflags = 0; - gfs2_glock_hold(gl); } /** @@ -1496,7 +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)) @@ -1508,8 +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; @@ -1619,69 +1590,28 @@ static inline bool needs_demote(struct gfs2_glock *gl) static void __gfs2_glock_dq(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; - struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; unsigned delay = 0; 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. + * This holder should not be cached, so mark it for demote. + * Note: this should be done before the check for needs_demote + * below. */ - 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 (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)) @@ -1705,8 +1635,17 @@ static void __gfs2_glock_dq(struct gfs2_holder *gh) void gfs2_glock_dq(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; + struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; spin_lock(&gl->gl_lockref.lock); + if (!gfs2_holder_queued(gh)) { + /* + * May have already been dequeued because the locking request + * was GL_ASYNC and it has failed in the meantime. + */ + goto out; + } + if (list_is_first(&gh->gh_list, &gl->gl_holders) && !test_bit(HIF_HOLDER, &gh->gh_iflags)) { spin_unlock(&gl->gl_lockref.lock); @@ -1715,7 +1654,26 @@ void gfs2_glock_dq(struct gfs2_holder *gh) spin_lock(&gl->gl_lockref.lock); } + /* + * 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); + } + __gfs2_glock_dq(gh); +out: spin_unlock(&gl->gl_lockref.lock); } @@ -1888,33 +1846,6 @@ 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); @@ -2306,8 +2237,6 @@ 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; |