summaryrefslogtreecommitdiffstats
path: root/fs/gfs2/glock.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/gfs2/glock.c')
-rw-r--r--fs/gfs2/glock.c2664
1 files changed, 2664 insertions, 0 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
new file mode 100644
index 000000000..d59ea71a8
--- /dev/null
+++ b/fs/gfs2/glock.c
@@ -0,0 +1,2664 @@
+// 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 <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/buffer_head.h>
+#include <linux/delay.h>
+#include <linux/sort.h>
+#include <linux/hash.h>
+#include <linux/jhash.h>
+#include <linux/kallsyms.h>
+#include <linux/gfs2_ondisk.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/workqueue.h>
+#include <linux/jiffies.h>
+#include <linux/rcupdate.h>
+#include <linux/rculist_bl.h>
+#include <linux/bit_spinlock.h>
+#include <linux/percpu.h>
+#include <linux/list_sort.h>
+#include <linux/lockref.h>
+#include <linux/rhashtable.h>
+#include <linux/pid_namespace.h>
+#include <linux/file.h>
+#include <linux/random.h>
+
+#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, bool may_cancel);
+static void request_demote(struct gfs2_glock *gl, unsigned int state,
+ unsigned long delay, bool remote);
+
+static struct dentry *gfs2_root;
+
+#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),
+ .automatic_shrinking = true,
+};
+
+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) {
+ struct gfs2_glock_aspace *gla =
+ container_of(gl, struct gfs2_glock_aspace, glock);
+ kmem_cache_free(gfs2_glock_aspace_cachep, gla);
+ } else
+ kmem_cache_free(gfs2_glock_cachep, gl);
+}
+
+static void __gfs2_glock_free(struct gfs2_glock *gl)
+{
+ 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);
+}
+
+void gfs2_glock_free(struct gfs2_glock *gl) {
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+
+ __gfs2_glock_free(gl);
+ if (atomic_dec_and_test(&sdp->sd_glock_disposal))
+ wake_up(&sdp->sd_kill_wait);
+}
+
+void gfs2_glock_free_later(struct gfs2_glock *gl) {
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+
+ spin_lock(&sdp->sd_dead_lock);
+ list_add(&gl->gl_dead, &sdp->sd_dead_glocks);
+ spin_unlock(&sdp->sd_dead_lock);
+ if (atomic_dec_and_test(&sdp->sd_glock_disposal))
+ wake_up(&sdp->sd_kill_wait);
+}
+
+static void gfs2_free_dead_glocks(struct gfs2_sbd *sdp)
+{
+ struct list_head *list = &sdp->sd_dead_glocks;
+
+ while(!list_empty(list)) {
+ struct gfs2_glock *gl;
+
+ gl = list_first_entry(list, struct gfs2_glock, gl_dead);
+ list_del(&gl->gl_dead);
+ __gfs2_glock_free(gl);
+ }
+}
+
+/**
+ * gfs2_glock_hold() - increment reference count on glock
+ * @gl: The glock to hold
+ *
+ */
+
+struct gfs2_glock *gfs2_glock_hold(struct gfs2_glock *gl)
+{
+ if (!lockref_get_not_zero(&gl->gl_lockref))
+ GLOCK_BUG_ON(gl, 1);
+ return gl;
+}
+
+/*
+ * 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) {
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+
+ if (!queue_delayed_work(sdp->sd_glock_wq, &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_put(struct gfs2_glock *gl)
+{
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+ struct address_space *mapping = gfs2_glock2aspace(gl);
+
+ lockref_mark_dead(&gl->gl_lockref);
+ spin_unlock(&gl->gl_lockref.lock);
+ GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
+ if (mapping) {
+ truncate_inode_pages_final(mapping);
+ if (!gfs2_withdrawn(sdp))
+ GLOCK_BUG_ON(gl, !mapping_empty(mapping));
+ }
+ trace_gfs2_glock_put(gl);
+ sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
+}
+
+static bool __gfs2_glock_put_or_lock(struct gfs2_glock *gl)
+{
+ if (lockref_put_or_lock(&gl->gl_lockref))
+ return true;
+ GLOCK_BUG_ON(gl, gl->gl_lockref.count != 1);
+ if (gl->gl_state != LM_ST_UNLOCKED) {
+ request_demote(gl, LM_ST_UNLOCKED, 0, false);
+ gfs2_glock_queue_work(gl, 0);
+ spin_unlock(&gl->gl_lockref.lock);
+ return true;
+ }
+ return false;
+}
+
+/**
+ * gfs2_glock_put() - Decrement reference count on glock
+ * @gl: The glock to put
+ *
+ */
+
+void gfs2_glock_put(struct gfs2_glock *gl)
+{
+ if (__gfs2_glock_put_or_lock(gl))
+ return;
+
+ __gfs2_glock_put(gl);
+}
+
+/*
+ * gfs2_glock_put_async - Decrement reference count without sleeping
+ * @gl: The glock to put
+ *
+ * Decrement the reference count on glock immediately unless it is the last
+ * reference. Defer putting the last reference to work queue context.
+ */
+void gfs2_glock_put_async(struct gfs2_glock *gl)
+{
+ if (__gfs2_glock_put_or_lock(gl))
+ return;
+
+ gfs2_glock_queue_work(gl, 0);
+ spin_unlock(&gl->gl_lockref.lock);
+}
+
+/**
+ * may_grant - check if it's ok to grant a new lock
+ * @gl: The glock
+ * @current_gh: One of the current holders of @gl
+ * @gh: The lock request which we wish to grant
+ *
+ * With our current compatibility rules, if a glock has one or more active
+ * holders (HIF_HOLDER flag set), any of those holders can be passed in as
+ * @current_gh; they are all the same as far as compatibility with the new @gh
+ * goes.
+ *
+ * Returns true if it's ok to grant the lock.
+ */
+
+static inline bool may_grant(struct gfs2_glock *gl,
+ struct gfs2_holder *current_gh,
+ struct gfs2_holder *gh)
+{
+ if (current_gh) {
+ GLOCK_BUG_ON(gl, !test_bit(HIF_HOLDER, &current_gh->gh_iflags));
+
+ switch(current_gh->gh_state) {
+ case LM_ST_EXCLUSIVE:
+ /*
+ * Here we make a special exception to grant holders
+ * who agree to share the EX lock with other holders
+ * who also have the bit set. If the original holder
+ * has the LM_FLAG_NODE_SCOPE bit set, we grant more
+ * holders with the bit set.
+ */
+ return gh->gh_state == LM_ST_EXCLUSIVE &&
+ (current_gh->gh_flags & LM_FLAG_NODE_SCOPE) &&
+ (gh->gh_flags & LM_FLAG_NODE_SCOPE);
+
+ case LM_ST_SHARED:
+ case LM_ST_DEFERRED:
+ return gh->gh_state == current_gh->gh_state;
+
+ default:
+ return false;
+ }
+ }
+
+ if (gl->gl_state == gh->gh_state)
+ return true;
+ if (gh->gh_flags & GL_EXACT)
+ return false;
+ if (gl->gl_state == LM_ST_EXCLUSIVE) {
+ return gh->gh_state == LM_ST_SHARED ||
+ gh->gh_state == LM_ST_DEFERRED;
+ }
+ if (gh->gh_flags & LM_FLAG_ANY)
+ return gl->gl_state != LM_ST_UNLOCKED;
+ return false;
+}
+
+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 = glock_sbd(gh->gh_gl);
+
+ wake_up(&sdp->sd_async_glock_wait);
+ }
+}
+
+/**
+ * do_error - Something unexpected has happened during a lock request
+ * @gl: The glock
+ * @ret: The status from the DLM
+ */
+
+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);
+ }
+}
+
+/**
+ * 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;
+}
+
+/*
+ * gfs2_instantiate - Call the glops instantiate function
+ * @gh: The glock holder
+ *
+ * Returns: 0 if instantiate was successful, or error.
+ */
+int gfs2_instantiate(struct gfs2_holder *gh)
+{
+ struct gfs2_glock *gl = gh->gh_gl;
+ const struct gfs2_glock_operations *glops = gl->gl_ops;
+ int ret;
+
+again:
+ if (!test_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags))
+ goto done;
+
+ /*
+ * Since we unlock the lockref lock, we set a flag to indicate
+ * instantiate is in progress.
+ */
+ if (test_and_set_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags)) {
+ wait_on_bit(&gl->gl_flags, GLF_INSTANTIATE_IN_PROG,
+ TASK_UNINTERRUPTIBLE);
+ /*
+ * Here we just waited for a different instantiate to finish.
+ * But that may not have been successful, as when a process
+ * locks an inode glock _before_ it has an actual inode to
+ * instantiate into. So we check again. This process might
+ * have an inode to instantiate, so might be successful.
+ */
+ goto again;
+ }
+
+ ret = glops->go_instantiate(gl);
+ if (!ret)
+ clear_bit(GLF_INSTANTIATE_NEEDED, &gl->gl_flags);
+ clear_and_wake_up_bit(GLF_INSTANTIATE_IN_PROG, &gl->gl_flags);
+ if (ret)
+ return ret;
+
+done:
+ if (glops->go_held)
+ return glops->go_held(gh);
+ return 0;
+}
+
+/**
+ * do_promote - promote as many requests as possible on the current queue
+ * @gl: The glock
+ */
+
+static void do_promote(struct gfs2_glock *gl)
+{
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+ struct gfs2_holder *gh, *current_gh;
+
+ if (gfs2_withdrawn(sdp)) {
+ do_error(gl, LM_OUT_ERROR);
+ return;
+ }
+
+ 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;
+ if (!may_grant(gl, current_gh, gh)) {
+ /*
+ * If we get here, it means we may not grant this
+ * holder for some reason.
+ */
+ if (current_gh)
+ do_error(gl, 0); /* Fail queued try locks */
+ break;
+ }
+ set_bit(HIF_HOLDER, &gh->gh_iflags);
+ trace_gfs2_promote(gh);
+ gfs2_holder_wake(gh);
+ if (!current_gh)
+ current_gh = gh;
+ }
+}
+
+/**
+ * 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;
+}
+
+/**
+ * find_last_waiter - find the last gh that's waiting for the glock
+ * @gl: the glock
+ *
+ * This also is a fast way of finding out if there are any waiters.
+ */
+
+static inline struct gfs2_holder *find_last_waiter(const struct gfs2_glock *gl)
+{
+ struct gfs2_holder *gh;
+
+ if (list_empty(&gl->gl_holders))
+ return NULL;
+ gh = list_last_entry(&gl->gl_holders, struct gfs2_holder, gh_list);
+ return test_bit(HIF_HOLDER, &gh->gh_iflags) ? NULL : gh;
+}
+
+/**
+ * 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)
+{
+ 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_set_demote(int nr, struct gfs2_glock *gl)
+{
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+
+ set_bit(nr, &gl->gl_flags);
+ smp_mb();
+ wake_up(&sdp->sd_async_glock_wait);
+}
+
+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;
+
+ if (!(ret & ~LM_OUT_ST_MASK)) {
+ unsigned state = ret & LM_OUT_ST_MASK;
+
+ trace_gfs2_glock_state_change(gl, state);
+ state_change(gl, state);
+ }
+
+ /* Demote to UN request arrived during demote to SH or DF */
+ if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
+ gl->gl_state != LM_ST_UNLOCKED &&
+ gl->gl_demote_state == LM_ST_UNLOCKED)
+ gl->gl_target = LM_ST_UNLOCKED;
+
+ /* Check for state != intended state */
+ if (unlikely(gl->gl_state != gl->gl_target)) {
+ struct gfs2_holder *gh = find_first_waiter(gl);
+
+ if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
+ if (ret & LM_OUT_CANCELED) {
+ list_del_init(&gh->gh_list);
+ trace_gfs2_glock_queue(gh, 0);
+ gfs2_holder_wake(gh);
+ gl->gl_target = gl->gl_state;
+ goto out;
+ }
+ /* 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(gl->gl_state) {
+ /* Unlocked due to conversion deadlock, try again */
+ case LM_ST_UNLOCKED:
+ do_xmote(gl, gh, gl->gl_target,
+ !test_bit(GLF_DEMOTE_IN_PROGRESS,
+ &gl->gl_flags));
+ break;
+ /* Conversion fails, unlock and try again */
+ case LM_ST_SHARED:
+ case LM_ST_DEFERRED:
+ do_xmote(gl, gh, LM_ST_UNLOCKED, false);
+ break;
+ default: /* Everything else */
+ fs_err(glock_sbd(gl),
+ "glock %u:%llu requested=%u ret=%u\n",
+ glock_type(gl), glock_number(gl),
+ gl->gl_req, ret);
+ GLOCK_BUG_ON(gl, 1);
+ }
+ return;
+ }
+
+ /* Fast path - we got what we asked for */
+ if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
+ clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
+ gfs2_demote_wake(gl);
+ }
+ if (gl->gl_state != LM_ST_UNLOCKED) {
+ if (glops->go_xmote_bh) {
+ int rv;
+
+ spin_unlock(&gl->gl_lockref.lock);
+ rv = glops->go_xmote_bh(gl);
+ spin_lock(&gl->gl_lockref.lock);
+ if (rv) {
+ do_error(gl, rv);
+ goto out;
+ }
+ }
+ do_promote(gl);
+ }
+out:
+ if (!test_bit(GLF_CANCELING, &gl->gl_flags))
+ clear_and_wake_up_bit(GLF_LOCK, &gl->gl_flags);
+}
+
+/**
+ * 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
+ * @may_cancel: Operation may be canceled
+ *
+ */
+
+static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh,
+ unsigned int target, bool may_cancel)
+__releases(&gl->gl_lockref.lock)
+__acquires(&gl->gl_lockref.lock)
+{
+ const struct gfs2_glock_operations *glops = gl->gl_ops;
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+ struct lm_lockstruct *ls = &sdp->sd_lockstruct;
+ int ret;
+
+ /*
+ * When a filesystem is withdrawing, the remaining cluster nodes will
+ * take care of recovering the withdrawing node's journal. We only
+ * need to make sure that once we trigger remote recovery, we won't
+ * write to the shared block device anymore. This means that here,
+ *
+ * - no new writes to the filesystem must be triggered (->go_sync()).
+ *
+ * - any cached data should be discarded by calling ->go_inval(), dirty
+ * or not and journaled or unjournaled.
+ *
+ * - no more dlm locking operations should be issued (->lm_lock()).
+ */
+
+ GLOCK_BUG_ON(gl, gl->gl_state == target);
+ GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
+
+ if (!glops->go_inval || !glops->go_sync)
+ goto skip_inval;
+
+ spin_unlock(&gl->gl_lockref.lock);
+ if (!gfs2_withdrawn(sdp)) {
+ ret = glops->go_sync(gl);
+ 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);
+ gfs2_withdraw(sdp);
+ }
+ }
+ }
+
+ if (target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED)
+ glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
+ spin_lock(&gl->gl_lockref.lock);
+
+skip_inval:
+ if (gfs2_withdrawn(sdp)) {
+ if (target != LM_ST_UNLOCKED)
+ target = LM_OUT_ERROR;
+ goto out;
+ }
+
+ if (ls->ls_ops->lm_lock) {
+ spin_unlock(&gl->gl_lockref.lock);
+ ret = ls->ls_ops->lm_lock(gl, target, gh ? gh->gh_flags : 0);
+ spin_lock(&gl->gl_lockref.lock);
+
+ if (!ret) {
+ if (may_cancel) {
+ set_bit(GLF_MAY_CANCEL, &gl->gl_flags);
+ smp_mb__after_atomic();
+ wake_up_bit(&gl->gl_flags, GLF_LOCK);
+ }
+ /* The operation will be completed asynchronously. */
+ gl->gl_lockref.count++;
+ return;
+ }
+
+ if (ret == -ENODEV) {
+ /*
+ * The lockspace has been released and the lock has
+ * been unlocked implicitly.
+ */
+ if (target != LM_ST_UNLOCKED) {
+ target = LM_OUT_ERROR;
+ goto out;
+ }
+ } else {
+ fs_err(sdp, "lm_lock ret %d\n", ret);
+ GLOCK_BUG_ON(gl, !gfs2_withdrawn(sdp));
+ return;
+ }
+ }
+
+out:
+ /* Complete the operation now. */
+ finish_xmote(gl, target);
+ gl->gl_lockref.count++;
+ gfs2_glock_queue_work(gl, 0);
+}
+
+/**
+ * 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;
+
+ if (test_bit(GLF_LOCK, &gl->gl_flags))
+ return;
+
+ /*
+ * The GLF_DEMOTE_IN_PROGRESS flag must only be set when the GLF_LOCK
+ * flag is set as well.
+ */
+ GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
+
+ if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
+ if (gl->gl_demote_state == gl->gl_state) {
+ gfs2_demote_wake(gl);
+ goto promote;
+ }
+
+ if (find_first_holder(gl))
+ return;
+ 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;
+ set_bit(GLF_LOCK, &gl->gl_flags);
+ do_xmote(gl, NULL, gl->gl_target, false);
+ return;
+ }
+
+promote:
+ do_promote(gl);
+ if (find_first_holder(gl))
+ return;
+ gh = find_first_waiter(gl);
+ if (!gh)
+ return;
+ if (nonblock)
+ goto out_sched;
+ 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 */
+ set_bit(GLF_LOCK, &gl->gl_flags);
+ do_xmote(gl, gh, gl->gl_target, true);
+ return;
+
+out_sched:
+ gl->gl_lockref.count++;
+ gfs2_glock_queue_work(gl, 0);
+}
+
+/**
+ * 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(glock_sbd(gl), prev_object == NULL))
+ gfs2_dump_glock(NULL, gl, true);
+}
+
+/**
+ * glock_clear_object - clear the gl_object field of a glock
+ * @gl: the glock
+ * @object: object the glock currently points at
+ */
+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(glock_sbd(gl), prev_object == object))
+ 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;
+
+ if (ri->ri_magic == 0)
+ ri->ri_magic = cpu_to_be32(GFS2_MAGIC);
+ if (ri->ri_magic == cpu_to_be32(GFS2_MAGIC))
+ ri->ri_generation_deleted = cpu_to_be64(generation);
+}
+
+bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation)
+{
+ struct gfs2_inode_lvb *ri = (void *)gl->gl_lksb.sb_lvbptr;
+
+ if (ri->ri_magic != cpu_to_be32(GFS2_MAGIC))
+ return false;
+ return generation <= be64_to_cpu(ri->ri_generation_deleted);
+}
+
+static void gfs2_glock_poke(struct gfs2_glock *gl)
+{
+ int flags = LM_FLAG_TRY_1CB | LM_FLAG_ANY | GL_SKIP;
+ struct gfs2_holder gh;
+ int error;
+
+ __gfs2_holder_init(gl, LM_ST_SHARED, flags, &gh, _RET_IP_);
+ error = gfs2_glock_nq(&gh);
+ if (!error)
+ gfs2_glock_dq(&gh);
+ gfs2_holder_uninit(&gh);
+}
+
+static struct gfs2_inode *gfs2_grab_existing_inode(struct gfs2_glock *gl)
+{
+ struct gfs2_inode *ip;
+
+ spin_lock(&gl->gl_lockref.lock);
+ ip = gl->gl_object;
+ if (ip && !igrab(&ip->i_inode))
+ ip = NULL;
+ spin_unlock(&gl->gl_lockref.lock);
+ if (ip) {
+ wait_on_new_inode(&ip->i_inode);
+ if (is_bad_inode(&ip->i_inode)) {
+ iput(&ip->i_inode);
+ ip = NULL;
+ }
+ }
+ return ip;
+}
+
+static void gfs2_try_to_evict(struct gfs2_glock *gl)
+{
+ struct gfs2_inode *ip;
+
+ /*
+ * If there is contention on the iopen glock and we have an inode, try
+ * to grab and release the inode so that it can be evicted. The
+ * GLF_DEFER_DELETE flag indicates to gfs2_evict_inode() that the inode
+ * should not be deleted locally. This will allow the remote node to
+ * go ahead and delete the inode without us having to do it, which will
+ * avoid rgrp glock thrashing.
+ *
+ * The remote node is likely still holding the corresponding inode
+ * glock, so it will run before we get to verify that the delete has
+ * happened below. (Verification is triggered by the call to
+ * gfs2_queue_verify_delete() in gfs2_evict_inode().)
+ */
+ ip = gfs2_grab_existing_inode(gl);
+ if (ip) {
+ set_bit(GLF_DEFER_DELETE, &gl->gl_flags);
+ d_prune_aliases(&ip->i_inode);
+ iput(&ip->i_inode);
+ clear_bit(GLF_DEFER_DELETE, &gl->gl_flags);
+
+ /* If the inode was evicted, gl->gl_object will now be NULL. */
+ ip = gfs2_grab_existing_inode(gl);
+ if (ip) {
+ gfs2_glock_poke(ip->i_gl);
+ iput(&ip->i_inode);
+ }
+ }
+}
+
+bool gfs2_queue_try_to_evict(struct gfs2_glock *gl)
+{
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+
+ if (test_and_set_bit(GLF_TRY_TO_EVICT, &gl->gl_flags))
+ return false;
+ return !mod_delayed_work(sdp->sd_delete_wq, &gl->gl_delete, 0);
+}
+
+bool gfs2_queue_verify_delete(struct gfs2_glock *gl, bool later)
+{
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+ unsigned long delay;
+
+ if (test_and_set_bit(GLF_VERIFY_DELETE, &gl->gl_flags))
+ return false;
+ delay = later ? HZ + get_random_long() % (HZ * 9) : 0;
+ return queue_delayed_work(sdp->sd_delete_wq, &gl->gl_delete, delay);
+}
+
+static void delete_work_func(struct work_struct *work)
+{
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct gfs2_glock *gl = container_of(dwork, struct gfs2_glock, gl_delete);
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+ bool verify_delete = test_and_clear_bit(GLF_VERIFY_DELETE, &gl->gl_flags);
+
+ /*
+ * Check for the GLF_VERIFY_DELETE above: this ensures that we won't
+ * immediately process GLF_VERIFY_DELETE work that the below call to
+ * gfs2_try_to_evict() queues.
+ */
+
+ if (test_and_clear_bit(GLF_TRY_TO_EVICT, &gl->gl_flags))
+ gfs2_try_to_evict(gl);
+
+ if (verify_delete) {
+ u64 no_addr = glock_number(gl);
+ struct inode *inode;
+
+ inode = gfs2_lookup_by_inum(sdp, no_addr, gl->gl_no_formal_ino,
+ GFS2_BLKST_UNLINKED);
+ if (IS_ERR(inode)) {
+ if (PTR_ERR(inode) == -EAGAIN &&
+ !test_bit(SDF_KILL, &sdp->sd_flags) &&
+ gfs2_queue_verify_delete(gl, true))
+ return;
+ } else {
+ d_prune_aliases(inode);
+ iput(inode);
+ }
+ }
+
+ gfs2_glock_put(gl);
+}
+
+static void glock_work_func(struct work_struct *work)
+{
+ struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
+ unsigned int drop_refs;
+ unsigned long delay;
+
+ spin_lock(&gl->gl_lockref.lock);
+again:
+ drop_refs = 1;
+ if (test_bit(GLF_HAVE_REPLY, &gl->gl_flags)) {
+ clear_bit(GLF_HAVE_REPLY, &gl->gl_flags);
+ finish_xmote(gl, gl->gl_reply);
+ drop_refs++;
+ }
+ delay = 0;
+ if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
+ gl->gl_state != LM_ST_UNLOCKED &&
+ gl->gl_demote_state != LM_ST_EXCLUSIVE) {
+ if (glock_type(gl) == LM_TYPE_INODE) {
+ 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);
+ gfs2_set_demote(GLF_DEMOTE, gl);
+ }
+ }
+ run_queue(gl, 0);
+ if (delay) {
+ /* Keep one glock reference for the work we requeue. */
+ drop_refs--;
+ gfs2_glock_queue_work(gl, delay);
+ }
+
+ /* Drop the remaining glock references manually. */
+ GLOCK_BUG_ON(gl, gl->gl_lockref.count < drop_refs);
+ gl->gl_lockref.count -= drop_refs;
+ if (!gl->gl_lockref.count) {
+ if (gl->gl_state != LM_ST_UNLOCKED) {
+ gl->gl_lockref.count++;
+ request_demote(gl, LM_ST_UNLOCKED, 0, false);
+ goto again;
+ }
+ __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 lm_lockname name = { .ln_number = number,
+ .ln_type = glops->go_type,
+ .ln_sbd = sdp };
+ struct gfs2_glock *gl, *tmp;
+ struct address_space *mapping;
+
+ gl = find_insert_glock(&name, NULL);
+ if (gl)
+ goto found;
+ if (!create)
+ return -ENOENT;
+
+ if (glops->go_flags & GLOF_ASPACE) {
+ struct gfs2_glock_aspace *gla =
+ kmem_cache_alloc(gfs2_glock_aspace_cachep, GFP_NOFS);
+ if (!gla)
+ return -ENOMEM;
+ gl = &gla->glock;
+ } else {
+ gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_NOFS);
+ if (!gl)
+ return -ENOMEM;
+ }
+ memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
+ gl->gl_ops = glops;
+
+ if (glops->go_flags & GLOF_LVB) {
+ gl->gl_lksb.sb_lvbptr = kzalloc(GDLM_LVB_SIZE, GFP_NOFS);
+ if (!gl->gl_lksb.sb_lvbptr) {
+ gfs2_glock_dealloc(&gl->gl_rcu);
+ return -ENOMEM;
+ }
+ }
+
+ atomic_inc(&sdp->sd_glock_disposal);
+ gl->gl_node.next = NULL;
+ gl->gl_flags = BIT(GLF_INITIAL);
+ if (glops->go_instantiate)
+ gl->gl_flags |= BIT(GLF_INSTANTIATE_NEEDED);
+ gl->gl_name = name;
+ lockref_init(&gl->gl_lockref);
+ lockdep_set_subclass(&gl->gl_lockref.lock, glops->go_subclass);
+ gl->gl_state = LM_ST_UNLOCKED;
+ gl->gl_target = LM_ST_UNLOCKED;
+ gl->gl_demote_state = LM_ST_EXCLUSIVE;
+ 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);
+ if (glock_type(gl) == LM_TYPE_IOPEN)
+ INIT_DELAYED_WORK(&gl->gl_delete, delete_work_func);
+
+ mapping = gfs2_glock2aspace(gl);
+ if (mapping) {
+ gfp_t gfp_mask;
+
+ mapping->a_ops = &gfs2_meta_aops;
+ mapping->host = sdp->sd_inode;
+ mapping->flags = 0;
+ gfp_mask = mapping_gfp_mask(sdp->sd_inode->i_mapping);
+ mapping_set_gfp_mask(mapping, gfp_mask);
+ mapping->writeback_index = 0;
+ }
+
+ tmp = find_insert_glock(&name, gl);
+ if (tmp) {
+ gfs2_glock_dealloc(&gl->gl_rcu);
+ if (atomic_dec_and_test(&sdp->sd_glock_disposal))
+ wake_up(&sdp->sd_kill_wait);
+
+ if (IS_ERR(tmp))
+ return PTR_ERR(tmp);
+ gl = tmp;
+ }
+
+found:
+ *glp = gl;
+ return 0;
+}
+
+/**
+ * __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
+ * @ip: caller's return address for debugging
+ */
+
+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 = 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_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_holder_ready - holder is ready and its error code can be collected
+ * @gh: the glock holder
+ *
+ * Called when a glock holder no longer needs to be waited for because it is
+ * now either held (HIF_HOLDER set; gh_error == 0), or acquiring the lock has
+ * failed (gh_error != 0).
+ */
+
+int gfs2_glock_holder_ready(struct gfs2_holder *gh)
+{
+ if (gh->gh_error || (gh->gh_flags & GL_SKIP))
+ return gh->gh_error;
+ gh->gh_error = gfs2_instantiate(gh);
+ if (gh->gh_error)
+ gfs2_glock_dq(gh);
+ return gh->gh_error;
+}
+
+/**
+ * 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 gfs2_glock_holder_ready(gh);
+}
+
+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
+ * @retries: number of retries attempted so far
+ *
+ * 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,
+ unsigned int retries)
+{
+ struct gfs2_sbd *sdp = glock_sbd(ghs[0].gh_gl);
+ unsigned long start_time = jiffies;
+ int i, ret = 0;
+ long timeout;
+
+ might_sleep();
+
+ timeout = GL_GLOCK_MIN_HOLD;
+ if (retries) {
+ unsigned int max_shift;
+ long incr;
+
+ /* Add a random delay and increase the timeout exponentially. */
+ max_shift = BITS_PER_LONG - 2 - __fls(GL_GLOCK_HOLD_INCR);
+ incr = min(GL_GLOCK_HOLD_INCR << min(retries - 1, max_shift),
+ 10 * HZ - GL_GLOCK_MIN_HOLD);
+ schedule_timeout_interruptible(get_random_long() % (incr / 3));
+ if (signal_pending(current))
+ goto interrupted;
+ timeout += (incr / 3) + get_random_long() % (incr / 3);
+ }
+
+ if (!wait_event_interruptible_timeout(sdp->sd_async_glock_wait,
+ !glocks_pending(num_gh, ghs), timeout)) {
+ ret = -ESTALE; /* request timed out. */
+ goto out;
+ }
+ if (signal_pending(current))
+ goto interrupted;
+
+ for (i = 0; i < num_gh; i++) {
+ struct gfs2_holder *gh = &ghs[i];
+ int ret2;
+
+ if (test_bit(HIF_HOLDER, &gh->gh_iflags)) {
+ gfs2_glock_update_hold_time(gh->gh_gl,
+ start_time);
+ }
+ ret2 = gfs2_glock_holder_ready(gh);
+ if (!ret)
+ ret = ret2;
+ }
+
+out:
+ if (ret) {
+ for (i = 0; i < num_gh; i++) {
+ struct gfs2_holder *gh = &ghs[i];
+
+ gfs2_glock_dq(gh);
+ }
+ }
+ return ret;
+
+interrupted:
+ ret = -EINTR;
+ goto out;
+}
+
+/**
+ * request_demote - process a demote request
+ * @gl: the glock
+ * @state: the state the caller wants us to change to
+ * @delay: zero to demote immediately; otherwise pending demote
+ * @remote: true if this came from a different cluster node
+ *
+ * There are only two requests that we are going to see in actual
+ * practise: LM_ST_SHARED and LM_ST_UNLOCKED
+ */
+
+static void request_demote(struct gfs2_glock *gl, unsigned int state,
+ unsigned long delay, bool remote)
+{
+ gfs2_set_demote(delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE, gl);
+ 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);
+}
+
+static bool gfs2_should_queue_trylock(struct gfs2_glock *gl,
+ struct gfs2_holder *gh)
+{
+ struct gfs2_holder *current_gh, *gh2;
+
+ current_gh = find_first_holder(gl);
+ if (current_gh && !may_grant(gl, current_gh, gh))
+ return false;
+
+ list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
+ if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
+ continue;
+ if (!(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
+ return false;
+ }
+ return true;
+}
+
+static inline bool pid_is_meaningful(const struct gfs2_holder *gh)
+{
+ if (!(gh->gh_flags & GL_NOPID))
+ return true;
+ return !test_bit(HIF_HOLDER, &gh->gh_iflags);
+}
+
+/**
+ * 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)
+{
+ struct gfs2_glock *gl = gh->gh_gl;
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+ struct gfs2_holder *gh2;
+
+ 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)) &&
+ !gfs2_should_queue_trylock(gl, gh)) {
+ gh->gh_error = GLR_TRYFAILED;
+ gfs2_holder_wake(gh);
+ return;
+ }
+
+ list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
+ if (likely(gh2->gh_owner_pid != gh->gh_owner_pid))
+ continue;
+ if (gh->gh_gl->gl_ops->go_type == LM_TYPE_FLOCK)
+ continue;
+ if (!pid_is_meaningful(gh2))
+ continue;
+ goto trap_recursive;
+ }
+ trace_gfs2_glock_queue(gh, 1);
+ gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
+ gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
+ list_add_tail(&gh->gh_list, &gl->gl_holders);
+ 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",
+ glock_type(gh2->gh_gl), 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",
+ glock_type(gh->gh_gl), 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;
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+ int error;
+
+ if (gfs2_withdrawn(sdp))
+ return -EIO;
+
+ if (gh->gh_flags & GL_NOBLOCK) {
+ struct gfs2_holder *current_gh;
+
+ error = -ECHILD;
+ spin_lock(&gl->gl_lockref.lock);
+ if (find_last_waiter(gl))
+ goto unlock;
+ current_gh = find_first_holder(gl);
+ if (!may_grant(gl, current_gh, gh))
+ goto unlock;
+ set_bit(HIF_HOLDER, &gh->gh_iflags);
+ list_add_tail(&gh->gh_list, &gl->gl_holders);
+ trace_gfs2_promote(gh);
+ error = 0;
+unlock:
+ spin_unlock(&gl->gl_lockref.lock);
+ return error;
+ }
+
+ gh->gh_error = 0;
+ spin_lock(&gl->gl_lockref.lock);
+ add_to_queue(gh);
+ if (unlikely((LM_FLAG_RECOVER & gh->gh_flags) &&
+ test_and_clear_bit(GLF_HAVE_FROZEN_REPLY, &gl->gl_flags))) {
+ set_bit(GLF_HAVE_REPLY, &gl->gl_flags);
+ gl->gl_lockref.count++;
+ gfs2_glock_queue_work(gl, 0);
+ }
+ run_queue(gl, 1);
+ spin_unlock(&gl->gl_lockref.lock);
+
+ error = 0;
+ 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;
+}
+
+static void __gfs2_glock_dq(struct gfs2_holder *gh)
+{
+ struct gfs2_glock *gl = gh->gh_gl;
+ unsigned delay = 0;
+ int fast_path = 0;
+
+ /*
+ * This holder should not be cached, so mark it for demote.
+ * Note: this should be done before the glock_needs_demote
+ * check below.
+ */
+ if (gh->gh_flags & GL_NOCACHE)
+ request_demote(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);
+ if (test_bit(HIF_WAIT, &gh->gh_iflags))
+ gfs2_holder_wake(gh);
+
+ /*
+ * If there hasn't been a demote request we are done.
+ * (Let the remaining holders, if any, keep holding it.)
+ */
+ if (!glock_needs_demote(gl)) {
+ if (list_empty(&gl->gl_holders))
+ fast_path = 1;
+ }
+
+ if (unlikely(!fast_path)) {
+ gl->gl_lockref.count++;
+ if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
+ !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
+ glock_type(gl) == LM_TYPE_INODE)
+ delay = gl->gl_hold_time;
+ gfs2_glock_queue_work(gl, delay);
+ }
+}
+
+/**
+ * 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;
+
+again:
+ 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) &&
+ test_bit(GLF_LOCK, &gl->gl_flags) &&
+ !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
+ !test_bit(GLF_CANCELING, &gl->gl_flags)) {
+ if (!test_bit(GLF_MAY_CANCEL, &gl->gl_flags)) {
+ struct wait_queue_head *wq;
+ DEFINE_WAIT(wait);
+
+ wq = bit_waitqueue(&gl->gl_flags, GLF_LOCK);
+ prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&gl->gl_lockref.lock);
+ schedule();
+ finish_wait(wq, &wait);
+ goto again;
+ }
+
+ set_bit(GLF_CANCELING, &gl->gl_flags);
+ spin_unlock(&gl->gl_lockref.lock);
+ glock_sbd(gl)->sd_lockstruct.ls_ops->lm_cancel(gl);
+ wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
+ spin_lock(&gl->gl_lockref.lock);
+ clear_bit(GLF_CANCELING, &gl->gl_flags);
+ clear_and_wake_up_bit(GLF_LOCK, &gl->gl_flags);
+ if (!gfs2_holder_queued(gh))
+ goto out;
+ }
+
+ __gfs2_glock_dq(gh);
+out:
+ 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 - synchronously acquire more than one glock in deadlock free order
+ * @num_gh: the number of structures
+ * @ghs: an array of struct gfs2_holder structures
+ * @p: placeholder for the holder structure to pass back
+ *
+ * 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++) {
+ 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:
+ return gfs2_glock_nq(ghs);
+ default:
+ if (num_gh <= 4)
+ break;
+ pph = kmalloc_objs(struct gfs2_holder *, num_gh, 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;
+
+ if (!lockref_get_not_dead(&gl->gl_lockref))
+ return;
+
+ spin_lock(&gl->gl_lockref.lock);
+ if (!list_empty(&gl->gl_holders) &&
+ glock_type(gl) == LM_TYPE_INODE) {
+ unsigned long now = jiffies;
+ unsigned long holdtime;
+
+ holdtime = gl->gl_tchange + gl->gl_hold_time;
+
+ if (time_before(now, holdtime))
+ delay = holdtime - now;
+ if (test_bit(GLF_HAVE_REPLY, &gl->gl_flags))
+ delay = gl->gl_hold_time;
+ }
+ request_demote(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 "recover" 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_RECOVER & 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 = &glock_sbd(gl)->sd_lockstruct;
+
+ spin_lock(&gl->gl_lockref.lock);
+ clear_bit(GLF_MAY_CANCEL, &gl->gl_flags);
+ gl->gl_reply = ret;
+
+ if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
+ if (gfs2_should_freeze(gl)) {
+ set_bit(GLF_HAVE_FROZEN_REPLY, &gl->gl_flags);
+ spin_unlock(&gl->gl_lockref.lock);
+ return;
+ }
+ }
+
+ gl->gl_lockref.count++;
+ set_bit(GLF_HAVE_REPLY, &gl->gl_flags);
+ gfs2_glock_queue_work(gl, 0);
+ spin_unlock(&gl->gl_lockref.lock);
+}
+
+/**
+ * glock_hash_walk - Call a function for glock in a hash bucket
+ * @examiner: the function
+ * @sdp: the filesystem
+ *
+ * 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 (glock_sbd(gl) == sdp)
+ examiner(gl);
+ }
+
+ rhashtable_walk_stop(&iter);
+ } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
+
+ rhashtable_walk_exit(&iter);
+}
+
+void gfs2_cancel_delete_work(struct gfs2_glock *gl)
+{
+ clear_bit(GLF_TRY_TO_EVICT, &gl->gl_flags);
+ clear_bit(GLF_VERIFY_DELETE, &gl->gl_flags);
+ if (cancel_delayed_work(&gl->gl_delete))
+ gfs2_glock_put(gl);
+}
+
+static void flush_delete_work(struct gfs2_glock *gl)
+{
+ if (glock_type(gl) == LM_TYPE_IOPEN) {
+ struct gfs2_sbd *sdp = glock_sbd(gl);
+
+ if (cancel_delayed_work(&gl->gl_delete)) {
+ queue_delayed_work(sdp->sd_delete_wq,
+ &gl->gl_delete, 0);
+ }
+ }
+}
+
+void gfs2_flush_delete_work(struct gfs2_sbd *sdp)
+{
+ glock_hash_walk(flush_delete_work, sdp);
+ flush_workqueue(sdp->sd_delete_wq);
+}
+
+/**
+ * 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_HAVE_FROZEN_REPLY, &gl->gl_flags))
+ return;
+ if (!lockref_get_not_dead(&gl->gl_lockref))
+ return;
+
+ spin_lock(&gl->gl_lockref.lock);
+ set_bit(GLF_HAVE_REPLY, &gl->gl_flags);
+ 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);
+}
+
+static void withdraw_glock(struct gfs2_glock *gl)
+{
+ spin_lock(&gl->gl_lockref.lock);
+ if (!lockref_is_dead(&gl->gl_lockref)) {
+ /*
+ * We don't want to write back any more dirty data. Unlock the
+ * remaining inode and resource group glocks; this will cause
+ * their ->go_inval() hooks to toss out all the remaining
+ * cached data, dirty or not.
+ */
+ if (gl->gl_ops->go_inval && gl->gl_state != LM_ST_UNLOCKED)
+ request_demote(gl, LM_ST_UNLOCKED, 0, false);
+ do_error(gl, LM_OUT_ERROR); /* remove pending waiters */
+ }
+ spin_unlock(&gl->gl_lockref.lock);
+}
+
+void gfs2_withdraw_glocks(struct gfs2_sbd *sdp)
+{
+ glock_hash_walk(withdraw_glock, sdp);
+}
+
+/**
+ * gfs2_wait_glocks - Wait for the remaining glocks to go away
+ * @sdp: the filesystem
+ *
+ * Called when unmounting the filesystem.
+ */
+
+void gfs2_wait_glocks(struct gfs2_sbd *sdp)
+{
+ unsigned long start = jiffies;
+ bool timed_out = false;
+
+ while (!timed_out) {
+ wait_event_timeout(sdp->sd_kill_wait,
+ !atomic_read(&sdp->sd_glock_disposal),
+ HZ * 60);
+ if (!atomic_read(&sdp->sd_glock_disposal))
+ break;
+ timed_out = time_after(jiffies, start + (HZ * 600));
+ fs_warn(sdp, "%u glocks left after %u seconds%s\n",
+ atomic_read(&sdp->sd_glock_disposal),
+ jiffies_to_msecs(jiffies - start) / 1000,
+ timed_out ? ":" : "; still waiting");
+ }
+ gfs2_lm_unmount(sdp);
+ gfs2_free_dead_glocks(sdp);
+ glock_hash_walk(dump_glock_func, sdp);
+ destroy_workqueue(sdp->sd_glock_wq);
+ sdp->sd_glock_wq = NULL;
+}
+
+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_RECOVER)
+ *p++ = 'e';
+ if (flags & LM_FLAG_ANY)
+ *p++ = 'A';
+ if (flags & LM_FLAG_NODE_SCOPE)
+ *p++ = 'n';
+ 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 (flags & GL_SKIP)
+ *p++ = 's';
+ *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)
+{
+ const char *comm = "(none)";
+ pid_t owner_pid = 0;
+ char flags_buf[32];
+
+ rcu_read_lock();
+ if (pid_is_meaningful(gh)) {
+ struct task_struct *gh_owner;
+
+ comm = "(ended)";
+ owner_pid = pid_nr(gh->gh_owner_pid);
+ gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
+ if (gh_owner)
+ comm = gh_owner->comm;
+ }
+ 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, (long)owner_pid, comm, (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_MAY_CANCEL, gflags))
+ *p++ = 'c';
+ if (test_bit(GLF_HAVE_REPLY, gflags))
+ *p++ = 'r';
+ if (test_bit(GLF_INITIAL, gflags))
+ *p++ = 'a';
+ if (test_bit(GLF_HAVE_FROZEN_REPLY, gflags))
+ *p++ = 'F';
+ if (!list_empty(&gl->gl_holders))
+ *p++ = 'q';
+ if (gl->gl_object)
+ *p++ = 'o';
+ if (test_bit(GLF_BLOCKING, gflags))
+ *p++ = 'b';
+ if (test_bit(GLF_INSTANTIATE_NEEDED, gflags))
+ *p++ = 'n';
+ if (test_bit(GLF_INSTANTIATE_IN_PROG, gflags))
+ *p++ = 'N';
+ if (test_bit(GLF_TRY_TO_EVICT, gflags))
+ *p++ = 'e';
+ if (test_bit(GLF_VERIFY_DELETE, gflags))
+ *p++ = 'E';
+ if (test_bit(GLF_DEFER_DELETE, gflags))
+ *p++ = 's';
+ if (test_bit(GLF_CANCELING, gflags))
+ *p++ = 'C';
+ *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 = glock_sbd(gl);
+ char fs_id_buf[sizeof(sdp->sd_fsname) + 7];
+ unsigned long nrpages = 0;
+
+ if (gl->gl_ops->go_flags & GLOF_ASPACE) {
+ struct address_space *mapping = gfs2_glock2aspace(gl);
+
+ nrpages = mapping->nrpages;
+ }
+ 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 p:%lu\n",
+ fs_id_buf, state2str(gl->gl_state),
+ glock_type(gl),
+ (unsigned long long) glock_number(gl),
+ 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, nrpages);
+
+ 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",
+ glock_type(gl),
+ (unsigned long long) glock_number(gl),
+ (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;
+
+ for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++)
+ init_waitqueue_head(glock_wait_table + i);
+
+ return 0;
+}
+
+void gfs2_glock_exit(void)
+{
+ rhashtable_destroy(&gl_hash_table);
+}
+
+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;
+ gfs2_glock_put_async(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 (glock_sbd(gl) != 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_sops = {
+ .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 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,
+};
+
+struct gfs2_glockfd_iter {
+ struct super_block *sb;
+ unsigned int tgid;
+ struct task_struct *task;
+ unsigned int fd;
+ struct file *file;
+};
+
+static struct task_struct *gfs2_glockfd_next_task(struct gfs2_glockfd_iter *i)
+{
+ struct pid_namespace *ns = task_active_pid_ns(current);
+ struct pid *pid;
+
+ if (i->task)
+ put_task_struct(i->task);
+
+ rcu_read_lock();
+retry:
+ i->task = NULL;
+ pid = find_ge_pid(i->tgid, ns);
+ if (pid) {
+ i->tgid = pid_nr_ns(pid, ns);
+ i->task = pid_task(pid, PIDTYPE_TGID);
+ if (!i->task) {
+ i->tgid++;
+ goto retry;
+ }
+ get_task_struct(i->task);
+ }
+ rcu_read_unlock();
+ return i->task;
+}
+
+static struct file *gfs2_glockfd_next_file(struct gfs2_glockfd_iter *i)
+{
+ if (i->file) {
+ fput(i->file);
+ i->file = NULL;
+ }
+
+ for(;; i->fd++) {
+ i->file = fget_task_next(i->task, &i->fd);
+ if (!i->file) {
+ i->fd = 0;
+ break;
+ }
+
+ if (file_inode(i->file)->i_sb == i->sb)
+ break;
+
+ fput(i->file);
+ }
+ return i->file;
+}
+
+static void *gfs2_glockfd_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct gfs2_glockfd_iter *i = seq->private;
+
+ if (*pos)
+ return NULL;
+ while (gfs2_glockfd_next_task(i)) {
+ if (gfs2_glockfd_next_file(i))
+ return i;
+ i->tgid++;
+ }
+ return NULL;
+}
+
+static void *gfs2_glockfd_seq_next(struct seq_file *seq, void *iter_ptr,
+ loff_t *pos)
+{
+ struct gfs2_glockfd_iter *i = seq->private;
+
+ (*pos)++;
+ i->fd++;
+ do {
+ if (gfs2_glockfd_next_file(i))
+ return i;
+ i->tgid++;
+ } while (gfs2_glockfd_next_task(i));
+ return NULL;
+}
+
+static void gfs2_glockfd_seq_stop(struct seq_file *seq, void *iter_ptr)
+{
+ struct gfs2_glockfd_iter *i = seq->private;
+
+ if (i->file)
+ fput(i->file);
+ if (i->task)
+ put_task_struct(i->task);
+}
+
+static void gfs2_glockfd_seq_show_flock(struct seq_file *seq,
+ struct gfs2_glockfd_iter *i)
+{
+ struct gfs2_file *fp = i->file->private_data;
+ struct gfs2_holder *fl_gh = &fp->f_fl_gh;
+ struct lm_lockname gl_name = { .ln_type = LM_TYPE_RESERVED };
+
+ if (!READ_ONCE(fl_gh->gh_gl))
+ return;
+
+ spin_lock(&i->file->f_lock);
+ if (gfs2_holder_initialized(fl_gh))
+ gl_name = fl_gh->gh_gl->gl_name;
+ spin_unlock(&i->file->f_lock);
+
+ if (gl_name.ln_type != LM_TYPE_RESERVED) {
+ seq_printf(seq, "%d %u %u/%llx\n",
+ i->tgid, i->fd, gl_name.ln_type,
+ (unsigned long long)gl_name.ln_number);
+ }
+}
+
+static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr)
+{
+ struct gfs2_glockfd_iter *i = seq->private;
+ struct inode *inode = file_inode(i->file);
+ struct gfs2_glock *gl;
+
+ inode_lock_shared(inode);
+ gl = GFS2_I(inode)->i_iopen_gh.gh_gl;
+ if (gl) {
+ seq_printf(seq, "%d %u %u/%llx\n",
+ i->tgid, i->fd, glock_type(gl),
+ (unsigned long long) glock_number(gl));
+ }
+ gfs2_glockfd_seq_show_flock(seq, i);
+ inode_unlock_shared(inode);
+ return 0;
+}
+
+static const struct seq_operations gfs2_glockfd_seq_ops = {
+ .start = gfs2_glockfd_seq_start,
+ .next = gfs2_glockfd_seq_next,
+ .stop = gfs2_glockfd_seq_stop,
+ .show = gfs2_glockfd_seq_show,
+};
+
+static int gfs2_glockfd_open(struct inode *inode, struct file *file)
+{
+ struct gfs2_glockfd_iter *i;
+ struct gfs2_sbd *sdp = inode->i_private;
+
+ i = __seq_open_private(file, &gfs2_glockfd_seq_ops,
+ sizeof(struct gfs2_glockfd_iter));
+ if (!i)
+ return -ENOMEM;
+ i->sb = sdp->sd_vfs;
+ return 0;
+}
+
+static const struct file_operations gfs2_glockfd_fops = {
+ .owner = THIS_MODULE,
+ .open = gfs2_glockfd_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release_private,
+};
+
+DEFINE_SEQ_ATTRIBUTE(gfs2_sbstats);
+
+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("glockfd", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp,
+ &gfs2_glockfd_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;
+}
generated by cgit v1.3.1 (git 2.54.0) at 2026-10-12 07:50:00 +0000