// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "gfs2.h" #include "incore.h" #include "glock.h" #include "glops.h" #include "inode.h" #include "lops.h" #include "meta_io.h" #include "quota.h" #include "super.h" #include "util.h" #include "bmap.h" #define CREATE_TRACE_POINTS #include "trace_gfs2.h" struct gfs2_glock_iter { struct gfs2_sbd *sdp; /* incore superblock */ struct rhashtable_iter hti; /* rhashtable iterator */ struct gfs2_glock *gl; /* current glock struct */ loff_t last_pos; /* last position */ }; typedef void (*glock_examiner) (struct gfs2_glock * gl); static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target); static struct dentry *gfs2_root; static struct workqueue_struct *glock_workqueue; struct workqueue_struct *gfs2_delete_workqueue; static LIST_HEAD(lru_list); static atomic_t lru_count = ATOMIC_INIT(0); static DEFINE_SPINLOCK(lru_lock); #define GFS2_GL_HASH_SHIFT 15 #define GFS2_GL_HASH_SIZE BIT(GFS2_GL_HASH_SHIFT) static const struct rhashtable_params ht_parms = { .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4, .key_len = offsetofend(struct lm_lockname, ln_type), .key_offset = offsetof(struct gfs2_glock, gl_name), .head_offset = offsetof(struct gfs2_glock, gl_node), }; static struct rhashtable gl_hash_table; #define GLOCK_WAIT_TABLE_BITS 12 #define GLOCK_WAIT_TABLE_SIZE (1 << GLOCK_WAIT_TABLE_BITS) static wait_queue_head_t glock_wait_table[GLOCK_WAIT_TABLE_SIZE] __cacheline_aligned; struct wait_glock_queue { struct lm_lockname *name; wait_queue_entry_t wait; }; static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) { struct wait_glock_queue *wait_glock = container_of(wait, struct wait_glock_queue, wait); struct lm_lockname *wait_name = wait_glock->name; struct lm_lockname *wake_name = key; if (wake_name->ln_sbd != wait_name->ln_sbd || wake_name->ln_number != wait_name->ln_number || wake_name->ln_type != wait_name->ln_type) return 0; return autoremove_wake_function(wait, mode, sync, key); } static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name) { u32 hash = jhash2((u32 *)name, ht_parms.key_len / 4, 0); return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS); } /** * wake_up_glock - Wake up waiters on a glock * @gl: the glock */ static void wake_up_glock(struct gfs2_glock *gl) { wait_queue_head_t *wq = glock_waitqueue(&gl->gl_name); if (waitqueue_active(wq)) __wake_up(wq, TASK_NORMAL, 1, &gl->gl_name); } static void gfs2_glock_dealloc(struct rcu_head *rcu) { struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu); kfree(gl->gl_lksb.sb_lvbptr); if (gl->gl_ops->go_flags & GLOF_ASPACE) kmem_cache_free(gfs2_glock_aspace_cachep, gl); else kmem_cache_free(gfs2_glock_cachep, gl); } /** * glock_blocked_by_withdraw - determine if we can still use a glock * @gl: the glock * * We need to allow some glocks to be enqueued, dequeued, promoted, and demoted * when we're withdrawn. For example, to maintain metadata integrity, we should * disallow the use of inode and rgrp glocks when withdrawn. Other glocks, like * iopen or the transaction glocks may be safely used because none of their * metadata goes through the journal. So in general, we should disallow all * glocks that are journaled, and allow all the others. One exception is: * we need to allow our active journal to be promoted and demoted so others * may recover it and we can reacquire it when they're done. */ static bool glock_blocked_by_withdraw(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; if (likely(!gfs2_withdrawn(sdp))) return false; if (gl->gl_ops->go_flags & GLOF_NONDISK) return false; if (!sdp->sd_jdesc || gl->gl_name.ln_number == sdp->sd_jdesc->jd_no_addr) return false; return true; } void gfs2_glock_free(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; BUG_ON(atomic_read(&gl->gl_revokes)); rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms); smp_mb(); wake_up_glock(gl); call_rcu(&gl->gl_rcu, gfs2_glock_dealloc); if (atomic_dec_and_test(&sdp->sd_glock_disposal)) wake_up(&sdp->sd_glock_wait); } /** * gfs2_glock_hold() - increment reference count on glock * @gl: The glock to hold * */ void gfs2_glock_hold(struct gfs2_glock *gl) { GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref)); lockref_get(&gl->gl_lockref); } /** * demote_ok - Check to see if it's ok to unlock a glock * @gl: the glock * * Returns: 1 if it's ok */ static int demote_ok(const struct gfs2_glock *gl) { const struct gfs2_glock_operations *glops = gl->gl_ops; if (gl->gl_state == LM_ST_UNLOCKED) return 0; if (!list_empty(&gl->gl_holders)) return 0; if (glops->go_demote_ok) return glops->go_demote_ok(gl); return 1; } void gfs2_glock_add_to_lru(struct gfs2_glock *gl) { if (!(gl->gl_ops->go_flags & GLOF_LRU)) return; spin_lock(&lru_lock); list_del(&gl->gl_lru); list_add_tail(&gl->gl_lru, &lru_list); if (!test_bit(GLF_LRU, &gl->gl_flags)) { set_bit(GLF_LRU, &gl->gl_flags); atomic_inc(&lru_count); } spin_unlock(&lru_lock); } static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl) { if (!(gl->gl_ops->go_flags & GLOF_LRU)) return; spin_lock(&lru_lock); if (test_bit(GLF_LRU, &gl->gl_flags)) { list_del_init(&gl->gl_lru); atomic_dec(&lru_count); clear_bit(GLF_LRU, &gl->gl_flags); } spin_unlock(&lru_lock); } /* * Enqueue the glock on the work queue. Passes one glock reference on to the * work queue. */ static void __gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) { if (!queue_delayed_work(glock_workqueue, &gl->gl_work, delay)) { /* * We are holding the lockref spinlock, and the work was still * queued above. The queued work (glock_work_func) takes that * spinlock before dropping its glock reference(s), so it * cannot have dropped them in the meantime. */ GLOCK_BUG_ON(gl, gl->gl_lockref.count < 2); gl->gl_lockref.count--; } } static void gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) { spin_lock(&gl->gl_lockref.lock); __gfs2_glock_queue_work(gl, delay); spin_unlock(&gl->gl_lockref.lock); } static void __gfs2_glock_put(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; struct address_space *mapping = gfs2_glock2aspace(gl); lockref_mark_dead(&gl->gl_lockref); gfs2_glock_remove_from_lru(gl); spin_unlock(&gl->gl_lockref.lock); GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders)); GLOCK_BUG_ON(gl, mapping && mapping->nrpages && !gfs2_withdrawn(sdp)); trace_gfs2_glock_put(gl); sdp->sd_lockstruct.ls_ops->lm_put_lock(gl); } /* * Cause the glock to be put in work queue context. */ void gfs2_glock_queue_put(struct gfs2_glock *gl) { gfs2_glock_queue_work(gl, 0); } /** * gfs2_glock_put() - Decrement reference count on glock * @gl: The glock to put * */ void gfs2_glock_put(struct gfs2_glock *gl) { if (lockref_put_or_lock(&gl->gl_lockref)) return; __gfs2_glock_put(gl); } /** * may_grant - check if its ok to grant a new lock * @gl: The glock * @gh: The lock request which we wish to grant * * Returns: true if its ok to grant the lock */ static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh) { const struct gfs2_holder *gh_head = list_first_entry(&gl->gl_holders, const struct gfs2_holder, gh_list); if ((gh->gh_state == LM_ST_EXCLUSIVE || gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head) return 0; if (gl->gl_state == gh->gh_state) return 1; if (gh->gh_flags & GL_EXACT) return 0; if (gl->gl_state == LM_ST_EXCLUSIVE) { if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED) return 1; if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED) return 1; } if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY)) return 1; return 0; } static void gfs2_holder_wake(struct gfs2_holder *gh) { clear_bit(HIF_WAIT, &gh->gh_iflags); smp_mb__after_atomic(); wake_up_bit(&gh->gh_iflags, HIF_WAIT); if (gh->gh_flags & GL_ASYNC) { struct gfs2_sbd *sdp = gh->gh_gl->gl_name.ln_sbd; wake_up(&sdp->sd_async_glock_wait); } } /** * do_error - Something unexpected has happened during a lock request * */ 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_HOLDER, &gh->gh_iflags)) continue; if (ret & LM_OUT_ERROR) gh->gh_error = -EIO; else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) gh->gh_error = GLR_TRYFAILED; else continue; list_del_init(&gh->gh_list); trace_gfs2_glock_queue(gh, 0); gfs2_holder_wake(gh); } } /** * do_promote - promote as many requests as possible on the current queue * @gl: The glock * * Returns: 1 if there is a blocked holder at the head of the list, or 2 * if a type specific operation is underway. */ static int do_promote(struct gfs2_glock *gl) __releases(&gl->gl_lockref.lock) __acquires(&gl->gl_lockref.lock) { const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_holder *gh, *tmp; int ret; restart: list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { if (test_bit(HIF_HOLDER, &gh->gh_iflags)) continue; if (may_grant(gl, gh)) { if (gh->gh_list.prev == &gl->gl_holders && glops->go_lock) { spin_unlock(&gl->gl_lockref.lock); /* FIXME: eliminate this eventually */ ret = glops->go_lock(gh); spin_lock(&gl->gl_lockref.lock); if (ret) { if (ret == 1) return 2; gh->gh_error = ret; list_del_init(&gh->gh_list); trace_gfs2_glock_queue(gh, 0); gfs2_holder_wake(gh); goto restart; } set_bit(HIF_HOLDER, &gh->gh_iflags); trace_gfs2_promote(gh, 1); gfs2_holder_wake(gh); goto restart; } set_bit(HIF_HOLDER, &gh->gh_iflags); trace_gfs2_promote(gh, 0); gfs2_holder_wake(gh); continue; } if (gh->gh_list.prev == &gl->gl_holders) return 1; do_error(gl, 0); break; } return 0; } /** * find_first_waiter - find the first gh that's waiting for the glock * @gl: the glock */ static inline struct gfs2_holder *find_first_waiter(const 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 gh; } return NULL; } /** * 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) { GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref)); if (held2) gl->gl_lockref.count++; else gl->gl_lockref.count--; } if (held1 && held2 && list_empty(&gl->gl_holders)) clear_bit(GLF_QUEUED, &gl->gl_flags); if (new_state != gl->gl_target) /* shorten our minimum hold time */ gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR, GL_GLOCK_MIN_HOLD); gl->gl_state = new_state; gl->gl_tchange = jiffies; } 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_atomic(); wake_up_bit(&gl->gl_flags, GLF_DEMOTE); } /** * finish_xmote - The DLM has replied to one of our lock requests * @gl: The glock * @ret: The status from the DLM * */ static void finish_xmote(struct gfs2_glock *gl, unsigned int ret) { const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_holder *gh; unsigned state = ret & LM_OUT_ST_MASK; int rv; spin_lock(&gl->gl_lockref.lock); trace_gfs2_glock_state_change(gl, state); state_change(gl, state); gh = find_first_waiter(gl); /* Demote to UN request arrived during demote to SH or DF */ if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) && state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED) gl->gl_target = LM_ST_UNLOCKED; /* Check for state != intended state */ if (unlikely(state != gl->gl_target)) { if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) { /* move to back of queue and try next entry */ if (ret & LM_OUT_CANCELED) { if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0) list_move_tail(&gh->gh_list, &gl->gl_holders); gh = find_first_waiter(gl); gl->gl_target = gh->gh_state; goto retry; } /* Some error or failed "try lock" - report it */ if ((ret & LM_OUT_ERROR) || (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) { gl->gl_target = gl->gl_state; do_error(gl, ret); goto out; } } switch(state) { /* Unlocked due to conversion deadlock, try again */ case LM_ST_UNLOCKED: retry: do_xmote(gl, gh, gl->gl_target); break; /* Conversion fails, unlock and try again */ case LM_ST_SHARED: case LM_ST_DEFERRED: do_xmote(gl, gh, LM_ST_UNLOCKED); break; default: /* Everything else */ fs_err(gl->gl_name.ln_sbd, "wanted %u got %u\n", gl->gl_target, state); GLOCK_BUG_ON(gl, 1); } spin_unlock(&gl->gl_lockref.lock); return; } /* Fast path - we got what we asked for */ if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) gfs2_demote_wake(gl); if (state != LM_ST_UNLOCKED) { if (glops->go_xmote_bh) { spin_unlock(&gl->gl_lockref.lock); rv = glops->go_xmote_bh(gl, gh); spin_lock(&gl->gl_lockref.lock); if (rv) { do_error(gl, rv); goto out; } } rv = do_promote(gl); if (rv == 2) goto out_locked; } out: clear_bit(GLF_LOCK, &gl->gl_flags); out_locked: spin_unlock(&gl->gl_lockref.lock); } /** * do_xmote - Calls the DLM to change the state of a lock * @gl: The lock state * @gh: The holder (only for promotes) * @target: The target lock state * */ static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target) __releases(&gl->gl_lockref.lock) __acquires(&gl->gl_lockref.lock) { const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0); int ret; if (target != LM_ST_UNLOCKED && glock_blocked_by_withdraw(gl) && gh && !(gh->gh_flags & LM_FLAG_NOEXP)) return; lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP | LM_FLAG_PRIORITY); GLOCK_BUG_ON(gl, gl->gl_state == target); GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target); if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) && glops->go_inval) { /* * If another process is already doing the invalidate, let that * finish first. The glock state machine will get back to this * holder again later. */ if (test_and_set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) return; do_error(gl, 0); /* Fail queued try locks */ } gl->gl_req = target; set_bit(GLF_BLOCKING, &gl->gl_flags); if ((gl->gl_req == LM_ST_UNLOCKED) || (gl->gl_state == LM_ST_EXCLUSIVE) || (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB))) clear_bit(GLF_BLOCKING, &gl->gl_flags); spin_unlock(&gl->gl_lockref.lock); if (glops->go_sync) { ret = glops->go_sync(gl); /* If we had a problem syncing (due to io errors or whatever, * we should not invalidate the metadata or tell dlm to * release the glock to other nodes. */ if (ret) { if (cmpxchg(&sdp->sd_log_error, 0, ret)) { fs_err(sdp, "Error %d syncing glock \n", ret); gfs2_dump_glock(NULL, gl, true); } goto skip_inval; } } if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) { /* * The call to go_sync should have cleared out the ail list. * If there are still items, we have a problem. We ought to * withdraw, but we can't because the withdraw code also uses * glocks. Warn about the error, dump the glock, then fall * through and wait for logd to do the withdraw for us. */ if ((atomic_read(&gl->gl_ail_count) != 0) && (!cmpxchg(&sdp->sd_log_error, 0, -EIO))) { gfs2_assert_warn(sdp, !atomic_read(&gl->gl_ail_count)); gfs2_dump_glock(NULL, gl, true); } glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA); clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags); } skip_inval: gfs2_glock_hold(gl); /* * Check for an error encountered since we called go_sync and go_inval. * If so, we can't withdraw from the glock code because the withdraw * code itself uses glocks (see function signal_our_withdraw) to * change the mount to read-only. Most importantly, we must not call * dlm to unlock the glock until the journal is in a known good state * (after journal replay) otherwise other nodes may use the object * (rgrp or dinode) and then later, journal replay will corrupt the * file system. The best we can do here is wait for the logd daemon * to see sd_log_error and withdraw, and in the meantime, requeue the * work for later. * * However, if we're just unlocking the lock (say, for unmount, when * gfs2_gl_hash_clear calls clear_glock) and recovery is complete * then it's okay to tell dlm to unlock it. */ if (unlikely(sdp->sd_log_error && !gfs2_withdrawn(sdp))) gfs2_withdraw_delayed(sdp); if (glock_blocked_by_withdraw(gl)) { if (target != LM_ST_UNLOCKED || test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags)) { gfs2_glock_queue_work(gl, GL_GLOCK_DFT_HOLD); goto out; } } if (sdp->sd_lockstruct.ls_ops->lm_lock) { /* lock_dlm */ ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags); if (ret == -EINVAL && gl->gl_target == LM_ST_UNLOCKED && target == LM_ST_UNLOCKED && test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) { finish_xmote(gl, target); gfs2_glock_queue_work(gl, 0); } else if (ret) { fs_err(sdp, "lm_lock ret %d\n", ret); GLOCK_BUG_ON(gl, !gfs2_withdrawn(sdp)); } } else { /* lock_nolock */ finish_xmote(gl, target); gfs2_glock_queue_work(gl, 0); } out: spin_lock(&gl->gl_lockref.lock); } /** * find_first_holder - find the first "holder" gh * @gl: the glock */ static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl) { struct gfs2_holder *gh; if (!list_empty(&gl->gl_holders)) { gh = list_first_entry(&gl->gl_holders, struct gfs2_holder, gh_list); if (test_bit(HIF_HOLDER, &gh->gh_iflags)) return gh; } return NULL; } /** * run_queue - do all outstanding tasks related to a glock * @gl: The glock in question * @nonblock: True if we must not block in run_queue * */ static void run_queue(struct gfs2_glock *gl, const int nonblock) __releases(&gl->gl_lockref.lock) __acquires(&gl->gl_lockref.lock) { struct gfs2_holder *gh = NULL; int ret; if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) return; GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)); if (test_bit(GLF_DEMOTE, &gl->gl_flags) && gl->gl_demote_state != gl->gl_state) { if (find_first_holder(gl)) goto out_unlock; if (nonblock) goto out_sched; set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags); GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE); gl->gl_target = gl->gl_demote_state; } else { if (test_bit(GLF_DEMOTE, &gl->gl_flags)) gfs2_demote_wake(gl); ret = do_promote(gl); if (ret == 0) goto out_unlock; if (ret == 2) goto out; gh = find_first_waiter(gl); gl->gl_target = gh->gh_state; if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) do_error(gl, 0); /* Fail queued try locks */ } do_xmote(gl, gh, gl->gl_target); out: return; out_sched: clear_bit(GLF_LOCK, &gl->gl_flags); smp_mb__after_atomic(); gl->gl_lockref.count++; __gfs2_glock_queue_work(gl, 0); return; out_unlock: clear_bit(GLF_LOCK, &gl->gl_flags); smp_mb__after_atomic(); return; } static void delete_work_func(struct work_struct *work) { struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete); struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; struct inode *inode; u64 no_addr = gl->gl_name.ln_number; /* If someone's using this glock to create a new dinode, the block must have been freed by another node, then re-used, in which case our iopen callback is too late after the fact. Ignore it. */ if (test_bit(GLF_INODE_CREATING, &gl->gl_flags)) goto out; inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED); if (!IS_ERR_OR_NULL(inode)) { d_prune_aliases(inode); iput(inode); } out: gfs2_glock_put(gl); } static void glock_work_func(struct work_struct *work) { unsigned long delay = 0; struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work); unsigned int drop_refs = 1; if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) { finish_xmote(gl, gl->gl_reply); drop_refs++; } spin_lock(&gl->gl_lockref.lock); if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && gl->gl_state != LM_ST_UNLOCKED && gl->gl_demote_state != LM_ST_EXCLUSIVE) { unsigned long holdtime, now = jiffies; holdtime = gl->gl_tchange + gl->gl_hold_time; if (time_before(now, holdtime)) delay = holdtime - now; if (!delay) { clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags); set_bit(GLF_DEMOTE, &gl->gl_flags); } } run_queue(gl, 0); if (delay) { /* Keep one glock reference for the work we requeue. */ drop_refs--; if (gl->gl_name.ln_type != LM_TYPE_INODE) delay = 0; __gfs2_glock_queue_work(gl, delay); } /* * Drop the remaining glock references manually here. (Mind that * __gfs2_glock_queue_work depends on the lockref spinlock begin held * here as well.) */ gl->gl_lockref.count -= drop_refs; if (!gl->gl_lockref.count) { __gfs2_glock_put(gl); return; } spin_unlock(&gl->gl_lockref.lock); } static struct gfs2_glock *find_insert_glock(struct lm_lockname *name, struct gfs2_glock *new) { struct wait_glock_queue wait; wait_queue_head_t *wq = glock_waitqueue(name); struct gfs2_glock *gl; wait.name = name; init_wait(&wait.wait); wait.wait.func = glock_wake_function; again: prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); rcu_read_lock(); if (new) { gl = rhashtable_lookup_get_insert_fast(&gl_hash_table, &new->gl_node, ht_parms); if (IS_ERR(gl)) goto out; } else { gl = rhashtable_lookup_fast(&gl_hash_table, name, ht_parms); } if (gl && !lockref_get_not_dead(&gl->gl_lockref)) { rcu_read_unlock(); schedule(); goto again; } out: rcu_read_unlock(); finish_wait(wq, &wait.wait); return gl; } /** * gfs2_glock_get() - Get a glock, or create one if one doesn't exist * @sdp: The GFS2 superblock * @number: the lock number * @glops: The glock_operations to use * @create: If 0, don't create the glock if it doesn't exist * @glp: the glock is returned here * * This does not lock a glock, just finds/creates structures for one. * * Returns: errno */ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, const struct gfs2_glock_operations *glops, int create, struct gfs2_glock **glp) { struct super_block *s = sdp->sd_vfs; struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type, .ln_sbd = sdp }; struct gfs2_glock *gl, *tmp; struct address_space *mapping; struct kmem_cache *cachep; int ret = 0; gl = find_insert_glock(&name, NULL); if (gl) { *glp = gl; return 0; } if (!create) return -ENOENT; if (glops->go_flags & GLOF_ASPACE) cachep = gfs2_glock_aspace_cachep; else cachep = gfs2_glock_cachep; gl = kmem_cache_alloc(cachep, GFP_NOFS); if (!gl) return -ENOMEM; memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb)); if (glops->go_flags & GLOF_LVB) { gl->gl_lksb.sb_lvbptr = kzalloc(GDLM_LVB_SIZE, GFP_NOFS); if (!gl->gl_lksb.sb_lvbptr) { kmem_cache_free(cachep, gl); return -ENOMEM; } } atomic_inc(&sdp->sd_glock_disposal); gl->gl_node.next = NULL; gl->gl_flags = 0; gl->gl_name = name; gl->gl_lockref.count = 1; gl->gl_state = LM_ST_UNLOCKED; gl->gl_target = LM_ST_UNLOCKED; gl->gl_demote_state = LM_ST_EXCLUSIVE; gl->gl_ops = glops; gl->gl_dstamp = 0; preempt_disable(); /* We use the global stats to estimate the initial per-glock stats */ gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type]; preempt_enable(); gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0; gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0; gl->gl_tchange = jiffies; gl->gl_object = NULL; gl->gl_hold_time = GL_GLOCK_DFT_HOLD; INIT_DELAYED_WORK(&gl->gl_work, glock_work_func); INIT_WORK(&gl->gl_delete, delete_work_func); mapping = gfs2_glock2aspace(gl); if (mapping) { mapping->a_ops = &gfs2_meta_aops; mapping->host = s->s_bdev->bd_inode; mapping->flags = 0; mapping_set_gfp_mask(mapping, GFP_NOFS); mapping->private_data = NULL; mapping->writeback_index = 0; } tmp = find_insert_glock(&name, gl); if (!tmp) { *glp = gl; goto out; } if (IS_ERR(tmp)) { ret = PTR_ERR(tmp); goto out_free; } *glp = tmp; out_free: kfree(gl->gl_lksb.sb_lvbptr); kmem_cache_free(cachep, gl); atomic_dec(&sdp->sd_glock_disposal); out: return ret; } /** * gfs2_holder_init - initialize a struct gfs2_holder in the default way * @gl: the glock * @state: the state we're requesting * @flags: the modifier flags * @gh: the holder structure * */ void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags, struct gfs2_holder *gh) { INIT_LIST_HEAD(&gh->gh_list); gh->gh_gl = gl; gh->gh_ip = _RET_IP_; gh->gh_owner_pid = get_pid(task_pid(current)); gh->gh_state = state; gh->gh_flags = flags; gh->gh_error = 0; gh->gh_iflags = 0; gfs2_glock_hold(gl); } /** * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it * @state: the state we're requesting * @flags: the modifier flags * @gh: the holder structure * * Don't mess with the glock. * */ void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh) { gh->gh_state = state; gh->gh_flags = flags; gh->gh_iflags = 0; gh->gh_ip = _RET_IP_; put_pid(gh->gh_owner_pid); gh->gh_owner_pid = get_pid(task_pid(current)); } /** * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference) * @gh: the holder structure * */ void gfs2_holder_uninit(struct gfs2_holder *gh) { put_pid(gh->gh_owner_pid); gfs2_glock_put(gh->gh_gl); gfs2_holder_mark_uninitialized(gh); gh->gh_ip = 0; } static void gfs2_glock_update_hold_time(struct gfs2_glock *gl, unsigned long start_time) { /* Have we waited longer that a second? */ if (time_after(jiffies, start_time + HZ)) { /* Lengthen the minimum hold time. */ gl->gl_hold_time = min(gl->gl_hold_time + GL_GLOCK_HOLD_INCR, GL_GLOCK_MAX_HOLD); } } /** * gfs2_glock_wait - wait on a glock acquisition * @gh: the glock holder * * Returns: 0 on success */ int gfs2_glock_wait(struct gfs2_holder *gh) { unsigned long start_time = jiffies; might_sleep(); wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE); gfs2_glock_update_hold_time(gh->gh_gl, start_time); return gh->gh_error; } static int glocks_pending(unsigned int num_gh, struct gfs2_holder *ghs) { int i; for (i = 0; i < num_gh; i++) if (test_bit(HIF_WAIT, &ghs[i].gh_iflags)) return 1; return 0; } /** * gfs2_glock_async_wait - wait on multiple asynchronous glock acquisitions * @num_gh: the number of holders in the array * @ghs: the glock holder array * * Returns: 0 on success, meaning all glocks have been granted and are held. * -ESTALE if the request timed out, meaning all glocks were released, * and the caller should retry the operation. */ int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs) { struct gfs2_sbd *sdp = ghs[0].gh_gl->gl_name.ln_sbd; int i, ret = 0, timeout = 0; unsigned long start_time = jiffies; bool keep_waiting; might_sleep(); /* * Total up the (minimum hold time * 2) of all glocks and use that to * determine the max amount of time we should wait. */ for (i = 0; i < num_gh; i++) timeout += ghs[i].gh_gl->gl_hold_time << 1; wait_for_dlm: if (!wait_event_timeout(sdp->sd_async_glock_wait, !glocks_pending(num_gh, ghs), timeout)) ret = -ESTALE; /* request timed out. */ /* * If dlm granted all our requests, we need to adjust the glock * minimum hold time values according to how long we waited. * * If our request timed out, we need to repeatedly release any held * glocks we acquired thus far to allow dlm to acquire the remaining * glocks without deadlocking. We cannot currently cancel outstanding * glock acquisitions. * * The HIF_WAIT bit tells us which requests still need a response from * dlm. * * If dlm sent us any errors, we return the first error we find. */ keep_waiting = false; for (i = 0; i < num_gh; i++) { /* Skip holders we have already dequeued below. */ if (!gfs2_holder_queued(&ghs[i])) continue; /* Skip holders with a pending DLM response. */ if (test_bit(HIF_WAIT, &ghs[i].gh_iflags)) { keep_waiting = true; continue; } if (test_bit(HIF_HOLDER, &ghs[i].gh_iflags)) { if (ret == -ESTALE) gfs2_glock_dq(&ghs[i]); else gfs2_glock_update_hold_time(ghs[i].gh_gl, start_time); } if (!ret) ret = ghs[i].gh_error; } if (keep_waiting) goto wait_for_dlm; /* * At this point, we've either acquired all locks or released them all. */ return ret; } /** * 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, unsigned long delay, bool remote) { int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE; set_bit(bit, &gl->gl_flags); if (gl->gl_demote_state == LM_ST_EXCLUSIVE) { gl->gl_demote_state = state; gl->gl_demote_time = jiffies; } else if (gl->gl_demote_state != LM_ST_UNLOCKED && gl->gl_demote_state != state) { gl->gl_demote_state = LM_ST_UNLOCKED; } if (gl->gl_ops->go_callback) gl->gl_ops->go_callback(gl, remote); trace_gfs2_demote_rq(gl, remote); } void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...) { struct va_format vaf; va_list args; va_start(args, fmt); if (seq) { seq_vprintf(seq, fmt, args); } else { vaf.fmt = fmt; vaf.va = &args; pr_err("%pV", &vaf); } va_end(args); } /** * add_to_queue - Add a holder to the wait queue (but look for recursion) * @gh: the holder structure to add * * Eventually we should move the recursive locking trap to a * debugging option or something like that. This is the fast * path and needs to have the minimum number of distractions. * */ static inline void add_to_queue(struct gfs2_holder *gh) __releases(&gl->gl_lockref.lock) __acquires(&gl->gl_lockref.lock) { struct gfs2_glock *gl = gh->gh_gl; struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; struct list_head *insert_pt = NULL; struct gfs2_holder *gh2; int try_futile = 0; GLOCK_BUG_ON(gl, gh->gh_owner_pid == NULL); if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags)) GLOCK_BUG_ON(gl, true); if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) { if (test_bit(GLF_LOCK, &gl->gl_flags)) try_futile = !may_grant(gl, gh); if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) goto fail; } list_for_each_entry(gh2, &gl->gl_holders, gh_list) { if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid && (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK))) goto trap_recursive; if (try_futile && !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) { fail: gh->gh_error = GLR_TRYFAILED; gfs2_holder_wake(gh); return; } if (test_bit(HIF_HOLDER, &gh2->gh_iflags)) continue; if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt)) insert_pt = &gh2->gh_list; } set_bit(GLF_QUEUED, &gl->gl_flags); trace_gfs2_glock_queue(gh, 1); gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT); gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT); if (likely(insert_pt == NULL)) { list_add_tail(&gh->gh_list, &gl->gl_holders); if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY)) goto do_cancel; return; } list_add_tail(&gh->gh_list, insert_pt); do_cancel: gh = list_first_entry(&gl->gl_holders, struct gfs2_holder, gh_list); if (!(gh->gh_flags & LM_FLAG_PRIORITY)) { spin_unlock(&gl->gl_lockref.lock); if (sdp->sd_lockstruct.ls_ops->lm_cancel) sdp->sd_lockstruct.ls_ops->lm_cancel(gl); spin_lock(&gl->gl_lockref.lock); } return; trap_recursive: fs_err(sdp, "original: %pSR\n", (void *)gh2->gh_ip); fs_err(sdp, "pid: %d\n", pid_nr(gh2->gh_owner_pid)); fs_err(sdp, "lock type: %d req lock state : %d\n", gh2->gh_gl->gl_name.ln_type, gh2->gh_state); fs_err(sdp, "new: %pSR\n", (void *)gh->gh_ip); fs_err(sdp, "pid: %d\n", pid_nr(gh->gh_owner_pid)); fs_err(sdp, "lock type: %d req lock state : %d\n", gh->gh_gl->gl_name.ln_type, gh->gh_state); gfs2_dump_glock(NULL, gl, true); BUG(); } /** * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock) * @gh: the holder structure * * if (gh->gh_flags & GL_ASYNC), this never returns an error * * Returns: 0, GLR_TRYFAILED, or errno on failure */ int gfs2_glock_nq(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; int error = 0; if (glock_blocked_by_withdraw(gl) && !(gh->gh_flags & LM_FLAG_NOEXP)) return -EIO; if (test_bit(GLF_LRU, &gl->gl_flags)) gfs2_glock_remove_from_lru(gl); spin_lock(&gl->gl_lockref.lock); add_to_queue(gh); if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) && test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) { set_bit(GLF_REPLY_PENDING, &gl->gl_flags); gl->gl_lockref.count++; __gfs2_glock_queue_work(gl, 0); } run_queue(gl, 1); spin_unlock(&gl->gl_lockref.lock); if (!(gh->gh_flags & GL_ASYNC)) error = gfs2_glock_wait(gh); return error; } /** * gfs2_glock_poll - poll to see if an async request has been completed * @gh: the holder * * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on */ int gfs2_glock_poll(struct gfs2_holder *gh) { return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1; } /** * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock) * @gh: the glock holder * */ 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; 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++; might_sleep(); wait_on_bit(&sdp->sd_flags, SDF_WITHDRAW_RECOVERY, TASK_UNINTERRUPTIBLE); } 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); if (find_first_holder(gl) == NULL) { if (list_empty(&gl->gl_holders) && !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && !test_bit(GLF_DEMOTE, &gl->gl_flags)) fast_path = 1; } if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl)) gfs2_glock_add_to_lru(gl); trace_gfs2_glock_queue(gh, 0); if (unlikely(!fast_path)) { gl->gl_lockref.count++; if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && !test_bit(GLF_DEMOTE, &gl->gl_flags) && gl->gl_name.ln_type == LM_TYPE_INODE) delay = gl->gl_hold_time; __gfs2_glock_queue_work(gl, delay); } spin_unlock(&gl->gl_lockref.lock); } void gfs2_glock_dq_wait(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; gfs2_glock_dq(gh); might_sleep(); wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE); } /** * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it * @gh: the holder structure * */ void gfs2_glock_dq_uninit(struct gfs2_holder *gh) { gfs2_glock_dq(gh); gfs2_holder_uninit(gh); } /** * gfs2_glock_nq_num - acquire a glock based on lock number * @sdp: the filesystem * @number: the lock number * @glops: the glock operations for the type of glock * @state: the state to acquire the glock in * @flags: modifier flags for the acquisition * @gh: the struct gfs2_holder * * Returns: errno */ int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number, const struct gfs2_glock_operations *glops, unsigned int state, u16 flags, struct gfs2_holder *gh) { struct gfs2_glock *gl; int error; error = gfs2_glock_get(sdp, number, glops, CREATE, &gl); if (!error) { error = gfs2_glock_nq_init(gl, state, flags, gh); gfs2_glock_put(gl); } return error; } /** * glock_compare - Compare two struct gfs2_glock structures for sorting * @arg_a: the first structure * @arg_b: the second structure * */ static int glock_compare(const void *arg_a, const void *arg_b) { const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a; const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b; const struct lm_lockname *a = &gh_a->gh_gl->gl_name; const struct lm_lockname *b = &gh_b->gh_gl->gl_name; if (a->ln_number > b->ln_number) return 1; if (a->ln_number < b->ln_number) return -1; BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type); return 0; } /** * nq_m_sync - synchonously acquire more than one glock in deadlock free order * @num_gh: the number of structures * @ghs: an array of struct gfs2_holder structures * * Returns: 0 on success (all glocks acquired), * errno on failure (no glocks acquired) */ static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs, struct gfs2_holder **p) { unsigned int x; int error = 0; for (x = 0; x < num_gh; x++) p[x] = &ghs[x]; sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL); for (x = 0; x < num_gh; x++) { p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC); error = gfs2_glock_nq(p[x]); if (error) { while (x--) gfs2_glock_dq(p[x]); break; } } return error; } /** * gfs2_glock_nq_m - acquire multiple glocks * @num_gh: the number of structures * @ghs: an array of struct gfs2_holder structures * * * Returns: 0 on success (all glocks acquired), * errno on failure (no glocks acquired) */ int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs) { struct gfs2_holder *tmp[4]; struct gfs2_holder **pph = tmp; int error = 0; switch(num_gh) { case 0: return 0; case 1: ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC); return gfs2_glock_nq(ghs); default: if (num_gh <= 4) break; pph = kmalloc_array(num_gh, sizeof(struct gfs2_holder *), GFP_NOFS); if (!pph) return -ENOMEM; } error = nq_m_sync(num_gh, ghs, pph); if (pph != tmp) kfree(pph); return error; } /** * gfs2_glock_dq_m - release multiple glocks * @num_gh: the number of structures * @ghs: an array of struct gfs2_holder structures * */ void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs) { while (num_gh--) gfs2_glock_dq(&ghs[num_gh]); } void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state) { unsigned long delay = 0; unsigned long holdtime; unsigned long now = jiffies; gfs2_glock_hold(gl); holdtime = gl->gl_tchange + gl->gl_hold_time; if (test_bit(GLF_QUEUED, &gl->gl_flags) && gl->gl_name.ln_type == LM_TYPE_INODE) { if (time_before(now, holdtime)) delay = holdtime - now; if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags)) delay = gl->gl_hold_time; } spin_lock(&gl->gl_lockref.lock); handle_callback(gl, state, delay, true); __gfs2_glock_queue_work(gl, delay); spin_unlock(&gl->gl_lockref.lock); } /** * gfs2_should_freeze - Figure out if glock should be frozen * @gl: The glock in question * * Glocks are not frozen if (a) the result of the dlm operation is * an error, (b) the locking operation was an unlock operation or * (c) if there is a "noexp" flagged request anywhere in the queue * * Returns: 1 if freezing should occur, 0 otherwise */ static int gfs2_should_freeze(const struct gfs2_glock *gl) { const struct gfs2_holder *gh; if (gl->gl_reply & ~LM_OUT_ST_MASK) return 0; if (gl->gl_target == LM_ST_UNLOCKED) return 0; list_for_each_entry(gh, &gl->gl_holders, gh_list) { if (test_bit(HIF_HOLDER, &gh->gh_iflags)) continue; if (LM_FLAG_NOEXP & gh->gh_flags) return 0; } return 1; } /** * gfs2_glock_complete - Callback used by locking * @gl: Pointer to the glock * @ret: The return value from the dlm * * The gl_reply field is under the gl_lockref.lock lock so that it is ok * to use a bitfield shared with other glock state fields. */ void gfs2_glock_complete(struct gfs2_glock *gl, int ret) { struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct; spin_lock(&gl->gl_lockref.lock); gl->gl_reply = ret; if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) { if (gfs2_should_freeze(gl)) { set_bit(GLF_FROZEN, &gl->gl_flags); spin_unlock(&gl->gl_lockref.lock); return; } } gl->gl_lockref.count++; set_bit(GLF_REPLY_PENDING, &gl->gl_flags); __gfs2_glock_queue_work(gl, 0); spin_unlock(&gl->gl_lockref.lock); } static int glock_cmp(void *priv, struct list_head *a, struct list_head *b) { struct gfs2_glock *gla, *glb; gla = list_entry(a, struct gfs2_glock, gl_lru); glb = list_entry(b, struct gfs2_glock, gl_lru); if (gla->gl_name.ln_number > glb->gl_name.ln_number) return 1; if (gla->gl_name.ln_number < glb->gl_name.ln_number) return -1; return 0; } /** * gfs2_dispose_glock_lru - Demote a list of glocks * @list: The list to dispose of * * Disposing of glocks may involve disk accesses, so that here we sort * the glocks by number (i.e. disk location of the inodes) so that if * there are any such accesses, they'll be sent in order (mostly). * * Must be called under the lru_lock, but may drop and retake this * lock. While the lru_lock is dropped, entries may vanish from the * list, but no new entries will appear on the list (since it is * private) */ static void gfs2_dispose_glock_lru(struct list_head *list) __releases(&lru_lock) __acquires(&lru_lock) { struct gfs2_glock *gl; list_sort(NULL, list, glock_cmp); while(!list_empty(list)) { gl = list_first_entry(list, struct gfs2_glock, gl_lru); list_del_init(&gl->gl_lru); if (!spin_trylock(&gl->gl_lockref.lock)) { add_back_to_lru: list_add(&gl->gl_lru, &lru_list); set_bit(GLF_LRU, &gl->gl_flags); atomic_inc(&lru_count); continue; } if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) { spin_unlock(&gl->gl_lockref.lock); goto add_back_to_lru; } gl->gl_lockref.count++; if (demote_ok(gl)) handle_callback(gl, LM_ST_UNLOCKED, 0, false); WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags)); __gfs2_glock_queue_work(gl, 0); spin_unlock(&gl->gl_lockref.lock); cond_resched_lock(&lru_lock); } } /** * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote * @nr: The number of entries to scan * * This function selects the entries on the LRU which are able to * be demoted, and then kicks off the process by calling * gfs2_dispose_glock_lru() above. */ static long gfs2_scan_glock_lru(int nr) { struct gfs2_glock *gl; LIST_HEAD(skipped); LIST_HEAD(dispose); long freed = 0; spin_lock(&lru_lock); while ((nr-- >= 0) && !list_empty(&lru_list)) { gl = list_first_entry(&lru_list, struct gfs2_glock, gl_lru); /* Test for being demotable */ if (!test_bit(GLF_LOCK, &gl->gl_flags)) { list_move(&gl->gl_lru, &dispose); atomic_dec(&lru_count); clear_bit(GLF_LRU, &gl->gl_flags); freed++; continue; } list_move(&gl->gl_lru, &skipped); } list_splice(&skipped, &lru_list); if (!list_empty(&dispose)) gfs2_dispose_glock_lru(&dispose); spin_unlock(&lru_lock); return freed; } static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) { if (!(sc->gfp_mask & __GFP_FS)) return SHRINK_STOP; return gfs2_scan_glock_lru(sc->nr_to_scan); } static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { return vfs_pressure_ratio(atomic_read(&lru_count)); } static struct shrinker glock_shrinker = { .seeks = DEFAULT_SEEKS, .count_objects = gfs2_glock_shrink_count, .scan_objects = gfs2_glock_shrink_scan, }; /** * examine_bucket - Call a function for glock in a hash bucket * @examiner: the function * @sdp: the filesystem * @bucket: the bucket * * Note that the function can be called multiple times on the same * object. So the user must ensure that the function can cope with * that. */ static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp) { struct gfs2_glock *gl; struct rhashtable_iter iter; rhashtable_walk_enter(&gl_hash_table, &iter); do { rhashtable_walk_start(&iter); while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl)) if (gl->gl_name.ln_sbd == sdp && lockref_get_not_dead(&gl->gl_lockref)) examiner(gl); rhashtable_walk_stop(&iter); } while (cond_resched(), gl == ERR_PTR(-EAGAIN)); rhashtable_walk_exit(&iter); } /** * thaw_glock - thaw out a glock which has an unprocessed reply waiting * @gl: The glock to thaw * */ static void thaw_glock(struct gfs2_glock *gl) { if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) { gfs2_glock_put(gl); return; } set_bit(GLF_REPLY_PENDING, &gl->gl_flags); gfs2_glock_queue_work(gl, 0); } /** * clear_glock - look at a glock and see if we can free it from glock cache * @gl: the glock to look at * */ static void clear_glock(struct gfs2_glock *gl) { gfs2_glock_remove_from_lru(gl); spin_lock(&gl->gl_lockref.lock); if (gl->gl_state != LM_ST_UNLOCKED) handle_callback(gl, LM_ST_UNLOCKED, 0, false); __gfs2_glock_queue_work(gl, 0); spin_unlock(&gl->gl_lockref.lock); } /** * gfs2_glock_thaw - Thaw any frozen glocks * @sdp: The super block * */ void gfs2_glock_thaw(struct gfs2_sbd *sdp) { glock_hash_walk(thaw_glock, sdp); } static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid) { spin_lock(&gl->gl_lockref.lock); gfs2_dump_glock(seq, gl, fsid); spin_unlock(&gl->gl_lockref.lock); } static void dump_glock_func(struct gfs2_glock *gl) { dump_glock(NULL, gl, true); } /** * gfs2_gl_hash_clear - Empty out the glock hash table * @sdp: the filesystem * @wait: wait until it's all gone * * Called when unmounting the filesystem. */ void gfs2_gl_hash_clear(struct gfs2_sbd *sdp) { set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags); flush_workqueue(glock_workqueue); glock_hash_walk(clear_glock, sdp); flush_workqueue(glock_workqueue); wait_event_timeout(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0, HZ * 600); glock_hash_walk(dump_glock_func, sdp); } void gfs2_glock_finish_truncate(struct gfs2_inode *ip) { struct gfs2_glock *gl = ip->i_gl; int ret; ret = gfs2_truncatei_resume(ip); gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0); spin_lock(&gl->gl_lockref.lock); clear_bit(GLF_LOCK, &gl->gl_flags); run_queue(gl, 1); spin_unlock(&gl->gl_lockref.lock); } static const char *state2str(unsigned state) { switch(state) { case LM_ST_UNLOCKED: return "UN"; case LM_ST_SHARED: return "SH"; case LM_ST_DEFERRED: return "DF"; case LM_ST_EXCLUSIVE: return "EX"; } return "??"; } static const char *hflags2str(char *buf, u16 flags, unsigned long iflags) { char *p = buf; if (flags & LM_FLAG_TRY) *p++ = 't'; if (flags & LM_FLAG_TRY_1CB) *p++ = 'T'; if (flags & LM_FLAG_NOEXP) *p++ = 'e'; if (flags & LM_FLAG_ANY) *p++ = 'A'; if (flags & LM_FLAG_PRIORITY) *p++ = 'p'; if (flags & GL_ASYNC) *p++ = 'a'; if (flags & GL_EXACT) *p++ = 'E'; if (flags & GL_NOCACHE) *p++ = 'c'; if (test_bit(HIF_HOLDER, &iflags)) *p++ = 'H'; if (test_bit(HIF_WAIT, &iflags)) *p++ = 'W'; if (test_bit(HIF_FIRST, &iflags)) *p++ = 'F'; *p = 0; return buf; } /** * dump_holder - print information about a glock holder * @seq: the seq_file struct * @gh: the glock holder * @fs_id_buf: pointer to file system id (if requested) * */ static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh, const char *fs_id_buf) { struct task_struct *gh_owner = NULL; char flags_buf[32]; rcu_read_lock(); if (gh->gh_owner_pid) gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID); gfs2_print_dbg(seq, "%s H: s:%s f:%s e:%d p:%ld [%s] %pS\n", fs_id_buf, state2str(gh->gh_state), hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags), gh->gh_error, gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1, gh_owner ? gh_owner->comm : "(ended)", (void *)gh->gh_ip); rcu_read_unlock(); } static const char *gflags2str(char *buf, const struct gfs2_glock *gl) { const unsigned long *gflags = &gl->gl_flags; char *p = buf; if (test_bit(GLF_LOCK, gflags)) *p++ = 'l'; if (test_bit(GLF_DEMOTE, gflags)) *p++ = 'D'; if (test_bit(GLF_PENDING_DEMOTE, gflags)) *p++ = 'd'; if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags)) *p++ = 'p'; if (test_bit(GLF_DIRTY, gflags)) *p++ = 'y'; if (test_bit(GLF_LFLUSH, gflags)) *p++ = 'f'; if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags)) *p++ = 'i'; if (test_bit(GLF_REPLY_PENDING, gflags)) *p++ = 'r'; if (test_bit(GLF_INITIAL, gflags)) *p++ = 'I'; if (test_bit(GLF_FROZEN, gflags)) *p++ = 'F'; if (test_bit(GLF_QUEUED, gflags)) *p++ = 'q'; if (test_bit(GLF_LRU, gflags)) *p++ = 'L'; if (gl->gl_object) *p++ = 'o'; if (test_bit(GLF_BLOCKING, gflags)) *p++ = 'b'; *p = 0; return buf; } /** * gfs2_dump_glock - print information about a glock * @seq: The seq_file struct * @gl: the glock * @fsid: If true, also dump the file system id * * The file format is as follows: * One line per object, capital letters are used to indicate objects * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented, * other objects are indented by a single space and follow the glock to * which they are related. Fields are indicated by lower case letters * followed by a colon and the field value, except for strings which are in * [] so that its possible to see if they are composed of spaces for * example. The field's are n = number (id of the object), f = flags, * t = type, s = state, r = refcount, e = error, p = pid. * */ void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl, bool fsid) { const struct gfs2_glock_operations *glops = gl->gl_ops; unsigned long long dtime; const struct gfs2_holder *gh; char gflags_buf[32]; struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; char fs_id_buf[sizeof(sdp->sd_fsname) + 7]; memset(fs_id_buf, 0, sizeof(fs_id_buf)); if (fsid && sdp) /* safety precaution */ sprintf(fs_id_buf, "fsid=%s: ", sdp->sd_fsname); dtime = jiffies - gl->gl_demote_time; dtime *= 1000000/HZ; /* demote time in uSec */ if (!test_bit(GLF_DEMOTE, &gl->gl_flags)) dtime = 0; gfs2_print_dbg(seq, "%sG: s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d " "v:%d r:%d m:%ld\n", fs_id_buf, state2str(gl->gl_state), gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number, gflags2str(gflags_buf, gl), state2str(gl->gl_target), state2str(gl->gl_demote_state), dtime, atomic_read(&gl->gl_ail_count), atomic_read(&gl->gl_revokes), (int)gl->gl_lockref.count, gl->gl_hold_time); list_for_each_entry(gh, &gl->gl_holders, gh_list) dump_holder(seq, gh, fs_id_buf); if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump) glops->go_dump(seq, gl, fs_id_buf); } static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr) { struct gfs2_glock *gl = iter_ptr; seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n", gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number, (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT], (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR], (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB], (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB], (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT], (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR], (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT], (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]); return 0; } static const char *gfs2_gltype[] = { "type", "reserved", "nondisk", "inode", "rgrp", "meta", "iopen", "flock", "plock", "quota", "journal", }; static const char *gfs2_stype[] = { [GFS2_LKS_SRTT] = "srtt", [GFS2_LKS_SRTTVAR] = "srttvar", [GFS2_LKS_SRTTB] = "srttb", [GFS2_LKS_SRTTVARB] = "srttvarb", [GFS2_LKS_SIRT] = "sirt", [GFS2_LKS_SIRTVAR] = "sirtvar", [GFS2_LKS_DCOUNT] = "dlm", [GFS2_LKS_QCOUNT] = "queue", }; #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype)) static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr) { struct gfs2_sbd *sdp = seq->private; loff_t pos = *(loff_t *)iter_ptr; unsigned index = pos >> 3; unsigned subindex = pos & 0x07; int i; if (index == 0 && subindex != 0) return 0; seq_printf(seq, "%-10s %8s:", gfs2_gltype[index], (index == 0) ? "cpu": gfs2_stype[subindex]); for_each_possible_cpu(i) { const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i); if (index == 0) seq_printf(seq, " %15u", i); else seq_printf(seq, " %15llu", (unsigned long long)lkstats-> lkstats[index - 1].stats[subindex]); } seq_putc(seq, '\n'); return 0; } int __init gfs2_glock_init(void) { int i, ret; ret = rhashtable_init(&gl_hash_table, &ht_parms); if (ret < 0) return ret; glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_FREEZABLE, 0); if (!glock_workqueue) { rhashtable_destroy(&gl_hash_table); return -ENOMEM; } gfs2_delete_workqueue = alloc_workqueue("delete_workqueue", WQ_MEM_RECLAIM | WQ_FREEZABLE, 0); if (!gfs2_delete_workqueue) { destroy_workqueue(glock_workqueue); rhashtable_destroy(&gl_hash_table); return -ENOMEM; } ret = register_shrinker(&glock_shrinker); if (ret) { destroy_workqueue(gfs2_delete_workqueue); destroy_workqueue(glock_workqueue); rhashtable_destroy(&gl_hash_table); return ret; } for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++) init_waitqueue_head(glock_wait_table + i); return 0; } void gfs2_glock_exit(void) { unregister_shrinker(&glock_shrinker); rhashtable_destroy(&gl_hash_table); destroy_workqueue(glock_workqueue); destroy_workqueue(gfs2_delete_workqueue); } static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n) { struct gfs2_glock *gl = gi->gl; if (gl) { if (n == 0) return; if (!lockref_put_not_zero(&gl->gl_lockref)) gfs2_glock_queue_put(gl); } for (;;) { gl = rhashtable_walk_next(&gi->hti); if (IS_ERR_OR_NULL(gl)) { if (gl == ERR_PTR(-EAGAIN)) { n = 1; continue; } gl = NULL; break; } if (gl->gl_name.ln_sbd != gi->sdp) continue; if (n <= 1) { if (!lockref_get_not_dead(&gl->gl_lockref)) continue; break; } else { if (__lockref_is_dead(&gl->gl_lockref)) continue; n--; } } gi->gl = gl; } static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos) __acquires(RCU) { struct gfs2_glock_iter *gi = seq->private; loff_t n; /* * We can either stay where we are, skip to the next hash table * entry, or start from the beginning. */ if (*pos < gi->last_pos) { rhashtable_walk_exit(&gi->hti); rhashtable_walk_enter(&gl_hash_table, &gi->hti); n = *pos + 1; } else { n = *pos - gi->last_pos; } rhashtable_walk_start(&gi->hti); gfs2_glock_iter_next(gi, n); gi->last_pos = *pos; return gi->gl; } static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos) { struct gfs2_glock_iter *gi = seq->private; (*pos)++; gi->last_pos = *pos; gfs2_glock_iter_next(gi, 1); return gi->gl; } static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr) __releases(RCU) { struct gfs2_glock_iter *gi = seq->private; rhashtable_walk_stop(&gi->hti); } static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr) { dump_glock(seq, iter_ptr, false); return 0; } static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos) { preempt_disable(); if (*pos >= GFS2_NR_SBSTATS) return NULL; return pos; } static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos) { (*pos)++; if (*pos >= GFS2_NR_SBSTATS) return NULL; return pos; } static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr) { preempt_enable(); } static const struct seq_operations gfs2_glock_seq_ops = { .start = gfs2_glock_seq_start, .next = gfs2_glock_seq_next, .stop = gfs2_glock_seq_stop, .show = gfs2_glock_seq_show, }; static const struct seq_operations gfs2_glstats_seq_ops = { .start = gfs2_glock_seq_start, .next = gfs2_glock_seq_next, .stop = gfs2_glock_seq_stop, .show = gfs2_glstats_seq_show, }; static const struct seq_operations gfs2_sbstats_seq_ops = { .start = gfs2_sbstats_seq_start, .next = gfs2_sbstats_seq_next, .stop = gfs2_sbstats_seq_stop, .show = gfs2_sbstats_seq_show, }; #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL) static int __gfs2_glocks_open(struct inode *inode, struct file *file, const struct seq_operations *ops) { int ret = seq_open_private(file, ops, sizeof(struct gfs2_glock_iter)); if (ret == 0) { struct seq_file *seq = file->private_data; struct gfs2_glock_iter *gi = seq->private; gi->sdp = inode->i_private; seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN); if (seq->buf) seq->size = GFS2_SEQ_GOODSIZE; /* * Initially, we are "before" the first hash table entry; the * first call to rhashtable_walk_next gets us the first entry. */ gi->last_pos = -1; gi->gl = NULL; rhashtable_walk_enter(&gl_hash_table, &gi->hti); } return ret; } static int gfs2_glocks_open(struct inode *inode, struct file *file) { return __gfs2_glocks_open(inode, file, &gfs2_glock_seq_ops); } static int gfs2_glocks_release(struct inode *inode, struct file *file) { struct seq_file *seq = file->private_data; struct gfs2_glock_iter *gi = seq->private; if (gi->gl) gfs2_glock_put(gi->gl); rhashtable_walk_exit(&gi->hti); return seq_release_private(inode, file); } static int gfs2_glstats_open(struct inode *inode, struct file *file) { return __gfs2_glocks_open(inode, file, &gfs2_glstats_seq_ops); } static int gfs2_sbstats_open(struct inode *inode, struct file *file) { int ret = seq_open(file, &gfs2_sbstats_seq_ops); if (ret == 0) { struct seq_file *seq = file->private_data; seq->private = inode->i_private; /* sdp */ } return ret; } static const struct file_operations gfs2_glocks_fops = { .owner = THIS_MODULE, .open = gfs2_glocks_open, .read = seq_read, .llseek = seq_lseek, .release = gfs2_glocks_release, }; static const struct file_operations gfs2_glstats_fops = { .owner = THIS_MODULE, .open = gfs2_glstats_open, .read = seq_read, .llseek = seq_lseek, .release = gfs2_glocks_release, }; static const struct file_operations gfs2_sbstats_fops = { .owner = THIS_MODULE, .open = gfs2_sbstats_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; void gfs2_create_debugfs_file(struct gfs2_sbd *sdp) { sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root); debugfs_create_file("glocks", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp, &gfs2_glocks_fops); debugfs_create_file("glstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp, &gfs2_glstats_fops); debugfs_create_file("sbstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp, &gfs2_sbstats_fops); } void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp) { debugfs_remove_recursive(sdp->debugfs_dir); sdp->debugfs_dir = NULL; } void gfs2_register_debugfs(void) { gfs2_root = debugfs_create_dir("gfs2", NULL); } void gfs2_unregister_debugfs(void) { debugfs_remove(gfs2_root); gfs2_root = NULL; }