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363275216c
kernel_optimize_test/fs/gfs2/glock.c
Steven Whitehouse 363275216c [GFS2] Reordering in deallocation to avoid recursive locking 
Despite my earlier careful search, there was a recursive lock left
in the deallocation code. This removes it. It also should speed up
deallocation be reducing the number of locking operations which take
place by using two "try lock" operations on the two locks involved in
inode deallocation which allows us to grab the locks out of order
(compared with NFS which grabs the inode lock first and the iopen
lock later). It is ok for us to fail while doing this since if it
does fail it means that someone else is still using the inode and
thus it wouldn't be possible to deallocate anyway.

This fixes the bug reported to me by Rob Kenna.

Cc: Rob Kenna <rkenna@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-04-28 10:46:21 -04:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/delay.h>
#include <linux/sort.h>
#include <linux/jhash.h>
#include <linux/kref.h>
#include <linux/kallsyms.h>
#include <linux/gfs2_ondisk.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>
#include "gfs2.h"
#include "lm_interface.h"
#include "incore.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "lm.h"
#include "lops.h"
#include "meta_io.h"
#include "quota.h"
#include "super.h"
#include "util.h"
/* Must be kept in sync with the beginning of struct gfs2_glock */
struct glock_plug {
struct list_head gl_list;
unsigned long gl_flags;
};
struct greedy {
struct gfs2_holder gr_gh;
struct work_struct gr_work;
};
typedef void (*glock_examiner) (struct gfs2_glock * gl);
/**
* relaxed_state_ok - is a requested lock compatible with the current lock mode?
* @actual: the current state of the lock
* @requested: the lock state that was requested by the caller
* @flags: the modifier flags passed in by the caller
*
* Returns: 1 if the locks are compatible, 0 otherwise
*/
static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
int flags)
{
if (actual == requested)
return 1;
if (flags & GL_EXACT)
return 0;
if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
return 1;
if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
return 1;
return 0;
}
/**
* gl_hash() - Turn glock number into hash bucket number
* @lock: The glock number
*
* Returns: The number of the corresponding hash bucket
*/
static unsigned int gl_hash(struct lm_lockname *name)
{
unsigned int h;
h = jhash(&name->ln_number, sizeof(uint64_t), 0);
h = jhash(&name->ln_type, sizeof(unsigned int), h);
h &= GFS2_GL_HASH_MASK;
return h;
}
/**
* glock_free() - Perform a few checks and then release struct gfs2_glock
* @gl: The glock to release
*
* Also calls lock module to release its internal structure for this glock.
*
*/
static void glock_free(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct inode *aspace = gl->gl_aspace;
gfs2_lm_put_lock(sdp, gl->gl_lock);
if (aspace)
gfs2_aspace_put(aspace);
kmem_cache_free(gfs2_glock_cachep, gl);
}
/**
* gfs2_glock_hold() - increment reference count on glock
* @gl: The glock to hold
*
*/
void gfs2_glock_hold(struct gfs2_glock *gl)
{
kref_get(&gl->gl_ref);
}
/* All work is done after the return from kref_put() so we
can release the write_lock before the free. */
static void kill_glock(struct kref *kref)
{
struct gfs2_glock *gl = container_of(kref, struct gfs2_glock, gl_ref);
struct gfs2_sbd *sdp = gl->gl_sbd;
gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
gfs2_assert(sdp, list_empty(&gl->gl_holders));
gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
gfs2_assert(sdp, list_empty(&gl->gl_waiters2));
gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
}
/**
* gfs2_glock_put() - Decrement reference count on glock
* @gl: The glock to put
*
*/
int gfs2_glock_put(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_gl_hash_bucket *bucket = gl->gl_bucket;
int rv = 0;
mutex_lock(&sdp->sd_invalidate_inodes_mutex);
write_lock(&bucket->hb_lock);
if (kref_put(&gl->gl_ref, kill_glock)) {
list_del_init(&gl->gl_list);
write_unlock(&bucket->hb_lock);
BUG_ON(spin_is_locked(&gl->gl_spin));
glock_free(gl);
rv = 1;
goto out;
}
write_unlock(&bucket->hb_lock);
out:
mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
return rv;
}
/**
* queue_empty - check to see if a glock's queue is empty
* @gl: the glock
* @head: the head of the queue to check
*
* This function protects the list in the event that a process already
* has a holder on the list and is adding a second holder for itself.
* The glmutex lock is what generally prevents processes from working
* on the same glock at once, but the special case of adding a second
* holder for yourself ("recursive" locking) doesn't involve locking
* glmutex, making the spin lock necessary.
*
* Returns: 1 if the queue is empty
*/
static inline int queue_empty(struct gfs2_glock *gl, struct list_head *head)
{
int empty;
spin_lock(&gl->gl_spin);
empty = list_empty(head);
spin_unlock(&gl->gl_spin);
return empty;
}
/**
* search_bucket() - Find struct gfs2_glock by lock number
* @bucket: the bucket to search
* @name: The lock name
*
* Returns: NULL, or the struct gfs2_glock with the requested number
*/
static struct gfs2_glock *search_bucket(struct gfs2_gl_hash_bucket *bucket,
struct lm_lockname *name)
{
struct gfs2_glock *gl;
list_for_each_entry(gl, &bucket->hb_list, gl_list) {
if (test_bit(GLF_PLUG, &gl->gl_flags))
continue;
if (!lm_name_equal(&gl->gl_name, name))
continue;
kref_get(&gl->gl_ref);
return gl;
}
return NULL;
}
/**
* gfs2_glock_find() - Find glock by lock number
* @sdp: The GFS2 superblock
* @name: The lock name
*
* Returns: NULL, or the struct gfs2_glock with the requested number
*/
struct gfs2_glock *gfs2_glock_find(struct gfs2_sbd *sdp,
struct lm_lockname *name)
{
struct gfs2_gl_hash_bucket *bucket = &sdp->sd_gl_hash[gl_hash(name)];
struct gfs2_glock *gl;
read_lock(&bucket->hb_lock);
gl = search_bucket(bucket, name);
read_unlock(&bucket->hb_lock);
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, uint64_t number,
struct gfs2_glock_operations *glops, int create,
struct gfs2_glock **glp)
{
struct lm_lockname name;
struct gfs2_glock *gl, *tmp;
struct gfs2_gl_hash_bucket *bucket;
int error;
name.ln_number = number;
name.ln_type = glops->go_type;
bucket = &sdp->sd_gl_hash[gl_hash(&name)];
read_lock(&bucket->hb_lock);
gl = search_bucket(bucket, &name);
read_unlock(&bucket->hb_lock);
if (gl || !create) {
*glp = gl;
return 0;
}
gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
if (!gl)
return -ENOMEM;
memset(gl, 0, sizeof(struct gfs2_glock));
INIT_LIST_HEAD(&gl->gl_list);
gl->gl_name = name;
kref_init(&gl->gl_ref);
spin_lock_init(&gl->gl_spin);
gl->gl_state = LM_ST_UNLOCKED;
INIT_LIST_HEAD(&gl->gl_holders);
INIT_LIST_HEAD(&gl->gl_waiters1);
INIT_LIST_HEAD(&gl->gl_waiters2);
INIT_LIST_HEAD(&gl->gl_waiters3);
gl->gl_ops = glops;
gl->gl_bucket = bucket;
INIT_LIST_HEAD(&gl->gl_reclaim);
gl->gl_sbd = sdp;
lops_init_le(&gl->gl_le, &gfs2_glock_lops);
INIT_LIST_HEAD(&gl->gl_ail_list);
/* If this glock protects actual on-disk data or metadata blocks,
create a VFS inode to manage the pages/buffers holding them. */
if (glops == &gfs2_inode_glops ||
glops == &gfs2_rgrp_glops ||
glops == &gfs2_meta_glops) {
gl->gl_aspace = gfs2_aspace_get(sdp);
if (!gl->gl_aspace) {
error = -ENOMEM;
goto fail;
}
}
error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
if (error)
goto fail_aspace;
write_lock(&bucket->hb_lock);
tmp = search_bucket(bucket, &name);
if (tmp) {
write_unlock(&bucket->hb_lock);
glock_free(gl);
gl = tmp;
} else {
list_add_tail(&gl->gl_list, &bucket->hb_list);
write_unlock(&bucket->hb_lock);
}
*glp = gl;
return 0;
fail_aspace:
if (gl->gl_aspace)
gfs2_aspace_put(gl->gl_aspace);
fail:
kmem_cache_free(gfs2_glock_cachep, gl);
return error;
}
/**
* 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, unsigned flags,
struct gfs2_holder *gh)
{
INIT_LIST_HEAD(&gh->gh_list);
gh->gh_gl = gl;
gh->gh_ip = (unsigned long)__builtin_return_address(0);
gh->gh_owner = current;
gh->gh_state = state;
gh->gh_flags = flags;
gh->gh_error = 0;
gh->gh_iflags = 0;
init_completion(&gh->gh_wait);
if (gh->gh_state == LM_ST_EXCLUSIVE)
gh->gh_flags |= GL_LOCAL_EXCL;
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, unsigned flags, struct gfs2_holder *gh)
{
gh->gh_state = state;
gh->gh_flags = flags;
if (gh->gh_state == LM_ST_EXCLUSIVE)
gh->gh_flags |= GL_LOCAL_EXCL;
gh->gh_iflags &= 1 << HIF_ALLOCED;
gh->gh_ip = (unsigned long)__builtin_return_address(0);
}
/**
* gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
* @gh: the holder structure
*
*/
void gfs2_holder_uninit(struct gfs2_holder *gh)
{
gfs2_glock_put(gh->gh_gl);
gh->gh_gl = NULL;
gh->gh_ip = 0;
}
/**
* gfs2_holder_get - get a struct gfs2_holder structure
* @gl: the glock
* @state: the state we're requesting
* @flags: the modifier flags
* @gfp_flags: __GFP_NOFAIL
*
* Figure out how big an impact this function has. Either:
* 1) Replace it with a cache of structures hanging off the struct gfs2_sbd
* 2) Leave it like it is
*
* Returns: the holder structure, NULL on ENOMEM
*/
struct gfs2_holder *gfs2_holder_get(struct gfs2_glock *gl, unsigned int state,
int flags, gfp_t gfp_flags)
{
struct gfs2_holder *gh;
gh = kmalloc(sizeof(struct gfs2_holder), gfp_flags);
if (!gh)
return NULL;
gfs2_holder_init(gl, state, flags, gh);
set_bit(HIF_ALLOCED, &gh->gh_iflags);
gh->gh_ip = (unsigned long)__builtin_return_address(0);
return gh;
}
/**
* gfs2_holder_put - get rid of a struct gfs2_holder structure
* @gh: the holder structure
*
*/
void gfs2_holder_put(struct gfs2_holder *gh)
{
gfs2_holder_uninit(gh);
kfree(gh);
}
/**
* rq_mutex - process a mutex request in the queue
* @gh: the glock holder
*
* Returns: 1 if the queue is blocked
*/
static int rq_mutex(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
list_del_init(&gh->gh_list);
/* gh->gh_error never examined. */
set_bit(GLF_LOCK, &gl->gl_flags);
complete(&gh->gh_wait);
return 1;
}
/**
* rq_promote - process a promote request in the queue
* @gh: the glock holder
*
* Acquire a new inter-node lock, or change a lock state to more restrictive.
*
* Returns: 1 if the queue is blocked
*/
static int rq_promote(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_glock_operations *glops = gl->gl_ops;
if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
if (list_empty(&gl->gl_holders)) {
gl->gl_req_gh = gh;
set_bit(GLF_LOCK, &gl->gl_flags);
spin_unlock(&gl->gl_spin);
if (atomic_read(&sdp->sd_reclaim_count) >
gfs2_tune_get(sdp, gt_reclaim_limit) &&
!(gh->gh_flags & LM_FLAG_PRIORITY)) {
gfs2_reclaim_glock(sdp);
gfs2_reclaim_glock(sdp);
}
glops->go_xmote_th(gl, gh->gh_state,
gh->gh_flags);
spin_lock(&gl->gl_spin);
}
return 1;
}
if (list_empty(&gl->gl_holders)) {
set_bit(HIF_FIRST, &gh->gh_iflags);
set_bit(GLF_LOCK, &gl->gl_flags);
} else {
struct gfs2_holder *next_gh;
if (gh->gh_flags & GL_LOCAL_EXCL)
return 1;
next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
gh_list);
if (next_gh->gh_flags & GL_LOCAL_EXCL)
return 1;
}
list_move_tail(&gh->gh_list, &gl->gl_holders);
gh->gh_error = 0;
set_bit(HIF_HOLDER, &gh->gh_iflags);
complete(&gh->gh_wait);
return 0;
}
/**
* rq_demote - process a demote request in the queue
* @gh: the glock holder
*
* Returns: 1 if the queue is blocked
*/
static int rq_demote(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_glock_operations *glops = gl->gl_ops;
if (!list_empty(&gl->gl_holders))
return 1;
if (gl->gl_state == gh->gh_state || gl->gl_state == LM_ST_UNLOCKED) {
list_del_init(&gh->gh_list);
gh->gh_error = 0;
spin_unlock(&gl->gl_spin);
if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
gfs2_holder_put(gh);
else
complete(&gh->gh_wait);
spin_lock(&gl->gl_spin);
} else {
gl->gl_req_gh = gh;
set_bit(GLF_LOCK, &gl->gl_flags);
spin_unlock(&gl->gl_spin);
if (gh->gh_state == LM_ST_UNLOCKED ||
gl->gl_state != LM_ST_EXCLUSIVE)
glops->go_drop_th(gl);
else
glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
spin_lock(&gl->gl_spin);
}
return 0;
}
/**
* rq_greedy - process a queued request to drop greedy status
* @gh: the glock holder
*
* Returns: 1 if the queue is blocked
*/
static int rq_greedy(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
list_del_init(&gh->gh_list);
/* gh->gh_error never examined. */
clear_bit(GLF_GREEDY, &gl->gl_flags);
spin_unlock(&gl->gl_spin);
gfs2_holder_uninit(gh);
kfree(container_of(gh, struct greedy, gr_gh));
spin_lock(&gl->gl_spin);
return 0;
}
/**
* run_queue - process holder structures on a glock
* @gl: the glock
*
*/
static void run_queue(struct gfs2_glock *gl)
{
struct gfs2_holder *gh;
int blocked = 1;
for (;;) {
if (test_bit(GLF_LOCK, &gl->gl_flags))
break;
if (!list_empty(&gl->gl_waiters1)) {
gh = list_entry(gl->gl_waiters1.next,
struct gfs2_holder, gh_list);
if (test_bit(HIF_MUTEX, &gh->gh_iflags))
blocked = rq_mutex(gh);
else
gfs2_assert_warn(gl->gl_sbd, 0);
} else if (!list_empty(&gl->gl_waiters2) &&
!test_bit(GLF_SKIP_WAITERS2, &gl->gl_flags)) {
gh = list_entry(gl->gl_waiters2.next,
struct gfs2_holder, gh_list);
if (test_bit(HIF_DEMOTE, &gh->gh_iflags))
blocked = rq_demote(gh);
else if (test_bit(HIF_GREEDY, &gh->gh_iflags))
blocked = rq_greedy(gh);
else
gfs2_assert_warn(gl->gl_sbd, 0);
} else if (!list_empty(&gl->gl_waiters3)) {
gh = list_entry(gl->gl_waiters3.next,
struct gfs2_holder, gh_list);
if (test_bit(HIF_PROMOTE, &gh->gh_iflags))
blocked = rq_promote(gh);
else
gfs2_assert_warn(gl->gl_sbd, 0);
} else
break;
if (blocked)
break;
}
}
/**
* gfs2_glmutex_lock - acquire a local lock on a glock
* @gl: the glock
*
* Gives caller exclusive access to manipulate a glock structure.
*/
void gfs2_glmutex_lock(struct gfs2_glock *gl)
{
struct gfs2_holder gh;
gfs2_holder_init(gl, 0, 0, &gh);
set_bit(HIF_MUTEX, &gh.gh_iflags);
spin_lock(&gl->gl_spin);
if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
list_add_tail(&gh.gh_list, &gl->gl_waiters1);
else
complete(&gh.gh_wait);
spin_unlock(&gl->gl_spin);
wait_for_completion(&gh.gh_wait);
gfs2_holder_uninit(&gh);
}
/**
* gfs2_glmutex_trylock - try to acquire a local lock on a glock
* @gl: the glock
*
* Returns: 1 if the glock is acquired
*/
int gfs2_glmutex_trylock(struct gfs2_glock *gl)
{
int acquired = 1;
spin_lock(&gl->gl_spin);
if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
acquired = 0;
spin_unlock(&gl->gl_spin);
return acquired;
}
/**
* gfs2_glmutex_unlock - release a local lock on a glock
* @gl: the glock
*
*/
void gfs2_glmutex_unlock(struct gfs2_glock *gl)
{
spin_lock(&gl->gl_spin);
clear_bit(GLF_LOCK, &gl->gl_flags);
run_queue(gl);
BUG_ON(!spin_is_locked(&gl->gl_spin));
spin_unlock(&gl->gl_spin);
}
/**
* handle_callback - add a demote request to a lock's queue
* @gl: the glock
* @state: the state the caller wants us to change to
*
*/
static void handle_callback(struct gfs2_glock *gl, unsigned int state)
{
struct gfs2_holder *gh, *new_gh = NULL;
restart:
spin_lock(&gl->gl_spin);
list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
if (test_bit(HIF_DEMOTE, &gh->gh_iflags) &&
gl->gl_req_gh != gh) {
if (gh->gh_state != state)
gh->gh_state = LM_ST_UNLOCKED;
goto out;
}
}
if (new_gh) {
list_add_tail(&new_gh->gh_list, &gl->gl_waiters2);
new_gh = NULL;
} else {
spin_unlock(&gl->gl_spin);
new_gh = gfs2_holder_get(gl, state, LM_FLAG_TRY,
GFP_KERNEL | __GFP_NOFAIL),
set_bit(HIF_DEMOTE, &new_gh->gh_iflags);
set_bit(HIF_DEALLOC, &new_gh->gh_iflags);
goto restart;
}
out:
spin_unlock(&gl->gl_spin);
if (new_gh)
gfs2_holder_put(new_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)
{
int held1, held2;
held1 = (gl->gl_state != LM_ST_UNLOCKED);
held2 = (new_state != LM_ST_UNLOCKED);
if (held1 != held2) {
if (held2)
gfs2_glock_hold(gl);
else
gfs2_glock_put(gl);
}
gl->gl_state = new_state;
}
/**
* xmote_bh - Called after the lock module is done acquiring a lock
* @gl: The glock in question
* @ret: the int returned from the lock module
*
*/
static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_glock_operations *glops = gl->gl_ops;
struct gfs2_holder *gh = gl->gl_req_gh;
int prev_state = gl->gl_state;
int op_done = 1;
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
state_change(gl, ret & LM_OUT_ST_MASK);
if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
if (glops->go_inval)
glops->go_inval(gl, DIO_METADATA | DIO_DATA);
} else if (gl->gl_state == LM_ST_DEFERRED) {
/* We might not want to do this here.
Look at moving to the inode glops. */
if (glops->go_inval)
glops->go_inval(gl, DIO_DATA);
}
/* Deal with each possible exit condition */
if (!gh)
gl->gl_stamp = jiffies;
else if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
gh->gh_error = -EIO;
spin_unlock(&gl->gl_spin);
} else if (test_bit(HIF_DEMOTE, &gh->gh_iflags)) {
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
if (gl->gl_state == gh->gh_state ||
gl->gl_state == LM_ST_UNLOCKED)
gh->gh_error = 0;
else {
if (gfs2_assert_warn(sdp, gh->gh_flags &
(LM_FLAG_TRY | LM_FLAG_TRY_1CB)) == -1)
fs_warn(sdp, "ret = 0x%.8X\n", ret);
gh->gh_error = GLR_TRYFAILED;
}
spin_unlock(&gl->gl_spin);
if (ret & LM_OUT_CANCELED)
handle_callback(gl, LM_ST_UNLOCKED); /* Lame */
} else if (ret & LM_OUT_CANCELED) {
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
gh->gh_error = GLR_CANCELED;
spin_unlock(&gl->gl_spin);
} else if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
spin_lock(&gl->gl_spin);
list_move_tail(&gh->gh_list, &gl->gl_holders);
gh->gh_error = 0;
set_bit(HIF_HOLDER, &gh->gh_iflags);
spin_unlock(&gl->gl_spin);
set_bit(HIF_FIRST, &gh->gh_iflags);
op_done = 0;
} else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
gh->gh_error = GLR_TRYFAILED;
spin_unlock(&gl->gl_spin);
} else {
if (gfs2_assert_withdraw(sdp, 0) == -1)
fs_err(sdp, "ret = 0x%.8X\n", ret);
}
if (glops->go_xmote_bh)
glops->go_xmote_bh(gl);
if (op_done) {
spin_lock(&gl->gl_spin);
gl->gl_req_gh = NULL;
gl->gl_req_bh = NULL;
clear_bit(GLF_LOCK, &gl->gl_flags);
run_queue(gl);
spin_unlock(&gl->gl_spin);
}
gfs2_glock_put(gl);
if (gh) {
if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
gfs2_holder_put(gh);
else
complete(&gh->gh_wait);
}
}
/**
* gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
* @gl: The glock in question
* @state: the requested state
* @flags: modifier flags to the lock call
*
*/
void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_glock_operations *glops = gl->gl_ops;
int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
LM_FLAG_NOEXP | LM_FLAG_ANY |
LM_FLAG_PRIORITY);
unsigned int lck_ret;
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
gfs2_assert_warn(sdp, state != gl->gl_state);
if (gl->gl_state == LM_ST_EXCLUSIVE) {
if (glops->go_sync)
glops->go_sync(gl,
DIO_METADATA | DIO_DATA | DIO_RELEASE);
}
gfs2_glock_hold(gl);
gl->gl_req_bh = xmote_bh;
lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state,
lck_flags);
if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
return;
if (lck_ret & LM_OUT_ASYNC)
gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
else
xmote_bh(gl, lck_ret);
}
/**
* drop_bh - Called after a lock module unlock completes
* @gl: the glock
* @ret: the return status
*
* Doesn't wake up the process waiting on the struct gfs2_holder (if any)
* Doesn't drop the reference on the glock the top half took out
*
*/
static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_glock_operations *glops = gl->gl_ops;
struct gfs2_holder *gh = gl->gl_req_gh;
clear_bit(GLF_PREFETCH, &gl->gl_flags);
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
gfs2_assert_warn(sdp, !ret);
state_change(gl, LM_ST_UNLOCKED);
if (glops->go_inval)
glops->go_inval(gl, DIO_METADATA | DIO_DATA);
if (gh) {
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
gh->gh_error = 0;
spin_unlock(&gl->gl_spin);
}
if (glops->go_drop_bh)
glops->go_drop_bh(gl);
spin_lock(&gl->gl_spin);
gl->gl_req_gh = NULL;
gl->gl_req_bh = NULL;
clear_bit(GLF_LOCK, &gl->gl_flags);
run_queue(gl);
spin_unlock(&gl->gl_spin);
gfs2_glock_put(gl);
if (gh) {
if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
gfs2_holder_put(gh);
else
complete(&gh->gh_wait);
}
}
/**
* gfs2_glock_drop_th - call into the lock module to unlock a lock
* @gl: the glock
*
*/
void gfs2_glock_drop_th(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_glock_operations *glops = gl->gl_ops;
unsigned int ret;
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
if (gl->gl_state == LM_ST_EXCLUSIVE) {
if (glops->go_sync)
glops->go_sync(gl,
DIO_METADATA | DIO_DATA | DIO_RELEASE);
}
gfs2_glock_hold(gl);
gl->gl_req_bh = drop_bh;
ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
return;
if (!ret)
drop_bh(gl, ret);
else
gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
}
/**
* do_cancels - cancel requests for locks stuck waiting on an expire flag
* @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
*
* Don't cancel GL_NOCANCEL requests.
*/
static void do_cancels(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
spin_lock(&gl->gl_spin);
while (gl->gl_req_gh != gh &&
!test_bit(HIF_HOLDER, &gh->gh_iflags) &&
!list_empty(&gh->gh_list)) {
if (gl->gl_req_bh &&
!(gl->gl_req_gh &&
(gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
spin_unlock(&gl->gl_spin);
gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
msleep(100);
spin_lock(&gl->gl_spin);
} else {
spin_unlock(&gl->gl_spin);
msleep(100);
spin_lock(&gl->gl_spin);
}
}
spin_unlock(&gl->gl_spin);
}
/**
* glock_wait_internal - wait on a glock acquisition
* @gh: the glock holder
*
* Returns: 0 on success
*/
static int glock_wait_internal(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_glock_operations *glops = gl->gl_ops;
if (test_bit(HIF_ABORTED, &gh->gh_iflags))
return -EIO;
if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
spin_lock(&gl->gl_spin);
if (gl->gl_req_gh != gh &&
!test_bit(HIF_HOLDER, &gh->gh_iflags) &&
!list_empty(&gh->gh_list)) {
list_del_init(&gh->gh_list);
gh->gh_error = GLR_TRYFAILED;
run_queue(gl);
spin_unlock(&gl->gl_spin);
return gh->gh_error;
}
spin_unlock(&gl->gl_spin);
}
if (gh->gh_flags & LM_FLAG_PRIORITY)
do_cancels(gh);
wait_for_completion(&gh->gh_wait);
if (gh->gh_error)
return gh->gh_error;
gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state,
gh->gh_state,
gh->gh_flags));
if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
if (glops->go_lock) {
gh->gh_error = glops->go_lock(gh);
if (gh->gh_error) {
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
spin_unlock(&gl->gl_spin);
}
}
spin_lock(&gl->gl_spin);
gl->gl_req_gh = NULL;
gl->gl_req_bh = NULL;
clear_bit(GLF_LOCK, &gl->gl_flags);
run_queue(gl);
spin_unlock(&gl->gl_spin);
}
return gh->gh_error;
}
static inline struct gfs2_holder *
find_holder_by_owner(struct list_head *head, struct task_struct *owner)
{
struct gfs2_holder *gh;
list_for_each_entry(gh, head, gh_list) {
if (gh->gh_owner == owner)
return gh;
}
return NULL;
}
/**
* add_to_queue - Add a holder to the wait queue (but look for recursion)
* @gh: the holder structure to add
*
*/
static void add_to_queue(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_holder *existing;
BUG_ON(!gh->gh_owner);
existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
if (existing) {
print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
BUG();
}
existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
if (existing) {
print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
BUG();
}
if (gh->gh_flags & LM_FLAG_PRIORITY)
list_add(&gh->gh_list, &gl->gl_waiters3);
else
list_add_tail(&gh->gh_list, &gl->gl_waiters3);
}
/**
* 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 = gl->gl_sbd;
int error = 0;
restart:
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
set_bit(HIF_ABORTED, &gh->gh_iflags);
return -EIO;
}
set_bit(HIF_PROMOTE, &gh->gh_iflags);
spin_lock(&gl->gl_spin);
add_to_queue(gh);
run_queue(gl);
spin_unlock(&gl->gl_spin);
if (!(gh->gh_flags & GL_ASYNC)) {
error = glock_wait_internal(gh);
if (error == GLR_CANCELED) {
msleep(100);
goto restart;
}
}
clear_bit(GLF_PREFETCH, &gl->gl_flags);
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)
{
struct gfs2_glock *gl = gh->gh_gl;
int ready = 0;
spin_lock(&gl->gl_spin);
if (test_bit(HIF_HOLDER, &gh->gh_iflags))
ready = 1;
else if (list_empty(&gh->gh_list)) {
if (gh->gh_error == GLR_CANCELED) {
spin_unlock(&gl->gl_spin);
msleep(100);
if (gfs2_glock_nq(gh))
return 1;
return 0;
} else
ready = 1;
}
spin_unlock(&gl->gl_spin);
return ready;
}
/**
* gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
* @gh: the holder structure
*
* Returns: 0, GLR_TRYFAILED, or errno on failure
*/
int gfs2_glock_wait(struct gfs2_holder *gh)
{
int error;
error = glock_wait_internal(gh);
if (error == GLR_CANCELED) {
msleep(100);
gh->gh_flags &= ~GL_ASYNC;
error = gfs2_glock_nq(gh);
}
return error;
}
/**
* 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_glock_operations *glops = gl->gl_ops;
if (gh->gh_flags & GL_SYNC)
set_bit(GLF_SYNC, &gl->gl_flags);
if (gh->gh_flags & GL_NOCACHE)
handle_callback(gl, LM_ST_UNLOCKED);
gfs2_glmutex_lock(gl);
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
if (list_empty(&gl->gl_holders)) {
spin_unlock(&gl->gl_spin);
if (glops->go_unlock)
glops->go_unlock(gh);
if (test_bit(GLF_SYNC, &gl->gl_flags)) {
if (glops->go_sync)
glops->go_sync(gl, DIO_METADATA | DIO_DATA);
}
gl->gl_stamp = jiffies;
spin_lock(&gl->gl_spin);
}
clear_bit(GLF_LOCK, &gl->gl_flags);
run_queue(gl);
spin_unlock(&gl->gl_spin);
}
/**
* gfs2_glock_prefetch - Try to prefetch a glock
* @gl: the glock
* @state: the state to prefetch in
* @flags: flags passed to go_xmote_th()
*
*/
void gfs2_glock_prefetch(struct gfs2_glock *gl, unsigned int state, int flags)
{
struct gfs2_glock_operations *glops = gl->gl_ops;
spin_lock(&gl->gl_spin);
if (test_bit(GLF_LOCK, &gl->gl_flags) ||
!list_empty(&gl->gl_holders) ||
!list_empty(&gl->gl_waiters1) ||
!list_empty(&gl->gl_waiters2) ||
!list_empty(&gl->gl_waiters3) ||
relaxed_state_ok(gl->gl_state, state, flags)) {
spin_unlock(&gl->gl_spin);
return;
}
set_bit(GLF_PREFETCH, &gl->gl_flags);
set_bit(GLF_LOCK, &gl->gl_flags);
spin_unlock(&gl->gl_spin);
glops->go_xmote_th(gl, state, flags);
}
/**
* gfs2_glock_force_drop - Force a glock to be uncached
* @gl: the glock
*
*/
void gfs2_glock_force_drop(struct gfs2_glock *gl)
{
struct gfs2_holder gh;
gfs2_holder_init(gl, LM_ST_UNLOCKED, 0, &gh);
set_bit(HIF_DEMOTE, &gh.gh_iflags);
spin_lock(&gl->gl_spin);
list_add_tail(&gh.gh_list, &gl->gl_waiters2);
run_queue(gl);
spin_unlock(&gl->gl_spin);
wait_for_completion(&gh.gh_wait);
gfs2_holder_uninit(&gh);
}
static void greedy_work(void *data)
{
struct greedy *gr = data;
struct gfs2_holder *gh = &gr->gr_gh;
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_glock_operations *glops = gl->gl_ops;
clear_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
if (glops->go_greedy)
glops->go_greedy(gl);
spin_lock(&gl->gl_spin);
if (list_empty(&gl->gl_waiters2)) {
clear_bit(GLF_GREEDY, &gl->gl_flags);
spin_unlock(&gl->gl_spin);
gfs2_holder_uninit(gh);
kfree(gr);
} else {
gfs2_glock_hold(gl);
list_add_tail(&gh->gh_list, &gl->gl_waiters2);
run_queue(gl);
spin_unlock(&gl->gl_spin);
gfs2_glock_put(gl);
}
}
/**
* gfs2_glock_be_greedy -
* @gl:
* @time:
*
* Returns: 0 if go_greedy will be called, 1 otherwise
*/
int gfs2_glock_be_greedy(struct gfs2_glock *gl, unsigned int time)
{
struct greedy *gr;
struct gfs2_holder *gh;
if (!time ||
gl->gl_sbd->sd_args.ar_localcaching ||
test_and_set_bit(GLF_GREEDY, &gl->gl_flags))
return 1;
gr = kmalloc(sizeof(struct greedy), GFP_KERNEL);
if (!gr) {
clear_bit(GLF_GREEDY, &gl->gl_flags);
return 1;
}
gh = &gr->gr_gh;
gfs2_holder_init(gl, 0, 0, gh);
set_bit(HIF_GREEDY, &gh->gh_iflags);
INIT_WORK(&gr->gr_work, greedy_work, gr);
set_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
schedule_delayed_work(&gr->gr_work, time);
return 0;
}
/**
* 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 aquisition
* @gh: the struct gfs2_holder
*
* Returns: errno
*/
int gfs2_glock_nq_num(struct gfs2_sbd *sdp, uint64_t number,
struct gfs2_glock_operations *glops, unsigned int state,
int 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)
{
struct gfs2_holder *gh_a = *(struct gfs2_holder **)arg_a;
struct gfs2_holder *gh_b = *(struct gfs2_holder **)arg_b;
struct lm_lockname *a = &gh_a->gh_gl->gl_name;
struct lm_lockname *b = &gh_b->gh_gl->gl_name;
int ret = 0;
if (a->ln_number > b->ln_number)
ret = 1;
else if (a->ln_number < b->ln_number)
ret = -1;
else {
if (gh_a->gh_state == LM_ST_SHARED &&
gh_b->gh_state == LM_ST_EXCLUSIVE)
ret = 1;
else if (!(gh_a->gh_flags & GL_LOCAL_EXCL) &&
(gh_b->gh_flags & GL_LOCAL_EXCL))
ret = 1;
}
return ret;
}
/**
* 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
*
* Figure out how big an impact this function has. Either:
* 1) Replace this code with code that calls gfs2_glock_prefetch()
* 2) Forget async stuff and just call nq_m_sync()
* 3) Leave it like it is
*
* 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)
{
int *e;
unsigned int x;
int borked = 0, serious = 0;
int error = 0;
if (!num_gh)
return 0;
if (num_gh == 1) {
ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
return gfs2_glock_nq(ghs);
}
e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
if (!e)
return -ENOMEM;
for (x = 0; x < num_gh; x++) {
ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
error = gfs2_glock_nq(&ghs[x]);
if (error) {
borked = 1;
serious = error;
num_gh = x;
break;
}
}
for (x = 0; x < num_gh; x++) {
error = e[x] = glock_wait_internal(&ghs[x]);
if (error) {
borked = 1;
if (error != GLR_TRYFAILED && error != GLR_CANCELED)
serious = error;
}
}
if (!borked) {
kfree(e);
return 0;
}
for (x = 0; x < num_gh; x++)
if (!e[x])
gfs2_glock_dq(&ghs[x]);
if (serious)
error = serious;
else {
for (x = 0; x < num_gh; x++)
gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
&ghs[x]);
error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
}
kfree(e);
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)
{
unsigned int x;
for (x = 0; x < num_gh; x++)
gfs2_glock_dq(&ghs[x]);
}
/**
* gfs2_glock_dq_uninit_m - release multiple glocks
* @num_gh: the number of structures
* @ghs: an array of struct gfs2_holder structures
*
*/
void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
{
unsigned int x;
for (x = 0; x < num_gh; x++)
gfs2_glock_dq_uninit(&ghs[x]);
}
/**
* gfs2_glock_prefetch_num - prefetch 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 aquisition
*
* Returns: errno
*/
void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, uint64_t number,
struct gfs2_glock_operations *glops,
unsigned int state, int flags)
{
struct gfs2_glock *gl;
int error;
if (atomic_read(&sdp->sd_reclaim_count) <
gfs2_tune_get(sdp, gt_reclaim_limit)) {
error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
if (!error) {
gfs2_glock_prefetch(gl, state, flags);
gfs2_glock_put(gl);
}
}
}
/**
* gfs2_lvb_hold - attach a LVB from a glock
* @gl: The glock in question
*
*/
int gfs2_lvb_hold(struct gfs2_glock *gl)
{
int error;
gfs2_glmutex_lock(gl);
if (!atomic_read(&gl->gl_lvb_count)) {
error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
if (error) {
gfs2_glmutex_unlock(gl);
return error;
}
gfs2_glock_hold(gl);
}
atomic_inc(&gl->gl_lvb_count);
gfs2_glmutex_unlock(gl);
return 0;
}
/**
* gfs2_lvb_unhold - detach a LVB from a glock
* @gl: The glock in question
*
*/
void gfs2_lvb_unhold(struct gfs2_glock *gl)
{
gfs2_glock_hold(gl);
gfs2_glmutex_lock(gl);
gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
if (atomic_dec_and_test(&gl->gl_lvb_count)) {
gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
gl->gl_lvb = NULL;
gfs2_glock_put(gl);
}
gfs2_glmutex_unlock(gl);
gfs2_glock_put(gl);
}
void gfs2_lvb_sync(struct gfs2_glock *gl)
{
gfs2_glmutex_lock(gl);
gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count));
if (!gfs2_assert_warn(gl->gl_sbd, gfs2_glock_is_held_excl(gl)))
gfs2_lm_sync_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
gfs2_glmutex_unlock(gl);
}
static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
unsigned int state)
{
struct gfs2_glock *gl;
gl = gfs2_glock_find(sdp, name);
if (!gl)
return;
if (gl->gl_ops->go_callback)
gl->gl_ops->go_callback(gl, state);
handle_callback(gl, state);
spin_lock(&gl->gl_spin);
run_queue(gl);
spin_unlock(&gl->gl_spin);
gfs2_glock_put(gl);
}
/**
* gfs2_glock_cb - Callback used by locking module
* @fsdata: Pointer to the superblock
* @type: Type of callback
* @data: Type dependent data pointer
*
* Called by the locking module when it wants to tell us something.
* Either we need to drop a lock, one of our ASYNC requests completed, or
* a journal from another client needs to be recovered.
*/
void gfs2_glock_cb(lm_fsdata_t *fsdata, unsigned int type, void *data)
{
struct gfs2_sbd *sdp = (struct gfs2_sbd *)fsdata;
switch (type) {
case LM_CB_NEED_E:
blocking_cb(sdp, data, LM_ST_UNLOCKED);
return;
case LM_CB_NEED_D:
blocking_cb(sdp, data, LM_ST_DEFERRED);
return;
case LM_CB_NEED_S:
blocking_cb(sdp, data, LM_ST_SHARED);
return;
case LM_CB_ASYNC: {
struct lm_async_cb *async = data;
struct gfs2_glock *gl;
gl = gfs2_glock_find(sdp, &async->lc_name);
if (gfs2_assert_warn(sdp, gl))
return;
if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
gl->gl_req_bh(gl, async->lc_ret);
gfs2_glock_put(gl);
return;
}
case LM_CB_NEED_RECOVERY:
gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
if (sdp->sd_recoverd_process)
wake_up_process(sdp->sd_recoverd_process);
return;
case LM_CB_DROPLOCKS:
gfs2_gl_hash_clear(sdp, NO_WAIT);
gfs2_quota_scan(sdp);
return;
default:
gfs2_assert_warn(sdp, 0);
return;
}
}
/**
* gfs2_try_toss_inode - try to remove a particular inode struct from cache
* sdp: the filesystem
* inum: the inode number
*
*/
void gfs2_try_toss_inode(struct gfs2_sbd *sdp, struct gfs2_inum *inum)
{
struct gfs2_glock *gl;
struct gfs2_inode *ip;
int error;
error = gfs2_glock_get(sdp, inum->no_addr, &gfs2_inode_glops,
NO_CREATE, &gl);
if (error || !gl)
return;
if (!gfs2_glmutex_trylock(gl))
goto out;
ip = gl->gl_object;
if (!ip)
goto out_unlock;
if (atomic_read(&ip->i_count))
goto out_unlock;
gfs2_inode_destroy(ip, 1);
out_unlock:
gfs2_glmutex_unlock(gl);
out:
gfs2_glock_put(gl);
}
/**
* gfs2_iopen_go_callback - Try to kick the inode/vnode associated with an
* iopen glock from memory
* @io_gl: the iopen glock
* @state: the state into which the glock should be put
*
*/
void gfs2_iopen_go_callback(struct gfs2_glock *io_gl, unsigned int state)
{
struct gfs2_glock *i_gl;
if (state != LM_ST_UNLOCKED)
return;
spin_lock(&io_gl->gl_spin);
i_gl = io_gl->gl_object;
if (i_gl) {
gfs2_glock_hold(i_gl);
spin_unlock(&io_gl->gl_spin);
} else {
spin_unlock(&io_gl->gl_spin);
return;
}
if (gfs2_glmutex_trylock(i_gl)) {
struct gfs2_inode *ip = i_gl->gl_object;
if (ip) {
gfs2_try_toss_vnode(ip);
gfs2_glmutex_unlock(i_gl);
gfs2_glock_schedule_for_reclaim(i_gl);
goto out;
}
gfs2_glmutex_unlock(i_gl);
}
out:
gfs2_glock_put(i_gl);
}
/**
* 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(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_glock_operations *glops = gl->gl_ops;
int demote = 1;
if (test_bit(GLF_STICKY, &gl->gl_flags))
demote = 0;
else if (test_bit(GLF_PREFETCH, &gl->gl_flags))
demote = time_after_eq(jiffies,
gl->gl_stamp +
gfs2_tune_get(sdp, gt_prefetch_secs) * HZ);
else if (glops->go_demote_ok)
demote = glops->go_demote_ok(gl);
return demote;
}
/**
* gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
* @gl: the glock
*
*/
void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
spin_lock(&sdp->sd_reclaim_lock);
if (list_empty(&gl->gl_reclaim)) {
gfs2_glock_hold(gl);
list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
atomic_inc(&sdp->sd_reclaim_count);
}
spin_unlock(&sdp->sd_reclaim_lock);
wake_up(&sdp->sd_reclaim_wq);
}
/**
* gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
* @sdp: the filesystem
*
* Called from gfs2_glockd() glock reclaim daemon, or when promoting a
* different glock and we notice that there are a lot of glocks in the
* reclaim list.
*
*/
void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
{
struct gfs2_glock *gl;
spin_lock(&sdp->sd_reclaim_lock);
if (list_empty(&sdp->sd_reclaim_list)) {
spin_unlock(&sdp->sd_reclaim_lock);
return;
}
gl = list_entry(sdp->sd_reclaim_list.next,
struct gfs2_glock, gl_reclaim);
list_del_init(&gl->gl_reclaim);
spin_unlock(&sdp->sd_reclaim_lock);
atomic_dec(&sdp->sd_reclaim_count);
atomic_inc(&sdp->sd_reclaimed);
if (gfs2_glmutex_trylock(gl)) {
if (gl->gl_ops == &gfs2_inode_glops) {
struct gfs2_inode *ip = gl->gl_object;
if (ip && !atomic_read(&ip->i_count))
gfs2_inode_destroy(ip, 1);
}
if (queue_empty(gl, &gl->gl_holders) &&
gl->gl_state != LM_ST_UNLOCKED &&
demote_ok(gl))
handle_callback(gl, LM_ST_UNLOCKED);
gfs2_glmutex_unlock(gl);
}
gfs2_glock_put(gl);
}
/**
* examine_bucket - Call a function for glock in a hash bucket
* @examiner: the function
* @sdp: the filesystem
* @bucket: the bucket
*
* Returns: 1 if the bucket has entries
*/
static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
struct gfs2_gl_hash_bucket *bucket)
{
struct glock_plug plug;
struct list_head *tmp;
struct gfs2_glock *gl;
int entries;
/* Add "plug" to end of bucket list, work back up list from there */
memset(&plug.gl_flags, 0, sizeof(unsigned long));
set_bit(GLF_PLUG, &plug.gl_flags);
write_lock(&bucket->hb_lock);
list_add(&plug.gl_list, &bucket->hb_list);
write_unlock(&bucket->hb_lock);
for (;;) {
write_lock(&bucket->hb_lock);
for (;;) {
tmp = plug.gl_list.next;
if (tmp == &bucket->hb_list) {
list_del(&plug.gl_list);
entries = !list_empty(&bucket->hb_list);
write_unlock(&bucket->hb_lock);
return entries;
}
gl = list_entry(tmp, struct gfs2_glock, gl_list);
/* Move plug up list */
list_move(&plug.gl_list, &gl->gl_list);
if (test_bit(GLF_PLUG, &gl->gl_flags))
continue;
/* examiner() must glock_put() */
gfs2_glock_hold(gl);
break;
}
write_unlock(&bucket->hb_lock);
examiner(gl);
}
}
/**
* scan_glock - look at a glock and see if we can reclaim it
* @gl: the glock to look at
*
*/
static void scan_glock(struct gfs2_glock *gl)
{
if (gfs2_glmutex_trylock(gl)) {
if (gl->gl_ops == &gfs2_inode_glops) {
struct gfs2_inode *ip = gl->gl_object;
if (ip && !atomic_read(&ip->i_count))
goto out_schedule;
}
if (queue_empty(gl, &gl->gl_holders) &&
gl->gl_state != LM_ST_UNLOCKED &&
demote_ok(gl))
goto out_schedule;
gfs2_glmutex_unlock(gl);
}
gfs2_glock_put(gl);
return;
out_schedule:
gfs2_glmutex_unlock(gl);
gfs2_glock_schedule_for_reclaim(gl);
gfs2_glock_put(gl);
}
/**
* gfs2_scand_internal - Look for glocks and inodes to toss from memory
* @sdp: the filesystem
*
*/
void gfs2_scand_internal(struct gfs2_sbd *sdp)
{
unsigned int x;
for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
examine_bucket(scan_glock, sdp, &sdp->sd_gl_hash[x]);
cond_resched();
}
}
/**
* 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)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
int released;
spin_lock(&sdp->sd_reclaim_lock);
if (!list_empty(&gl->gl_reclaim)) {
list_del_init(&gl->gl_reclaim);
atomic_dec(&sdp->sd_reclaim_count);
spin_unlock(&sdp->sd_reclaim_lock);
released = gfs2_glock_put(gl);
gfs2_assert(sdp, !released);
} else {
spin_unlock(&sdp->sd_reclaim_lock);
}
if (gfs2_glmutex_trylock(gl)) {
if (gl->gl_ops == &gfs2_inode_glops) {
struct gfs2_inode *ip = gl->gl_object;
if (ip && !atomic_read(&ip->i_count))
gfs2_inode_destroy(ip, 1);
}
if (queue_empty(gl, &gl->gl_holders) &&
gl->gl_state != LM_ST_UNLOCKED)
handle_callback(gl, LM_ST_UNLOCKED);
gfs2_glmutex_unlock(gl);
}
gfs2_glock_put(gl);
}
/**
* 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, or when inter-node lock manager
* requests DROPLOCKS because it is running out of capacity.
*/
void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
{
unsigned long t;
unsigned int x;
int cont;
t = jiffies;
for (;;) {
cont = 0;
for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
if (examine_bucket(clear_glock, sdp,
&sdp->sd_gl_hash[x]))
cont = 1;
if (!wait || !cont)
break;
if (time_after_eq(jiffies,
t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
fs_warn(sdp, "Unmount seems to be stalled. "
"Dumping lock state...\n");
gfs2_dump_lockstate(sdp);
t = jiffies;
}
/* invalidate_inodes() requires that the sb inodes list
not change, but an async completion callback for an
unlock can occur which does glock_put() which
can call iput() which will change the sb inodes list.
invalidate_inodes_mutex prevents glock_put()'s during
an invalidate_inodes() */
mutex_lock(&sdp->sd_invalidate_inodes_mutex);
invalidate_inodes(sdp->sd_vfs);
mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
yield();
}
}
/*
* Diagnostic routines to help debug distributed deadlock
*/
/**
* dump_holder - print information about a glock holder
* @str: a string naming the type of holder
* @gh: the glock holder
*
* Returns: 0 on success, -ENOBUFS when we run out of space
*/
static int dump_holder(char *str, struct gfs2_holder *gh)
{
unsigned int x;
int error = -ENOBUFS;
printk(KERN_INFO " %s\n", str);
printk(KERN_INFO " owner = %ld\n",
(gh->gh_owner) ? (long)gh->gh_owner->pid : -1);
printk(KERN_INFO " gh_state = %u\n", gh->gh_state);
printk(KERN_INFO " gh_flags =");
for (x = 0; x < 32; x++)
if (gh->gh_flags & (1 << x))
printk(" %u", x);
printk(" \n");
printk(KERN_INFO " error = %d\n", gh->gh_error);
printk(KERN_INFO " gh_iflags =");
for (x = 0; x < 32; x++)
if (test_bit(x, &gh->gh_iflags))
printk(" %u", x);
printk(" \n");
print_symbol(KERN_INFO " initialized at: %s\n", gh->gh_ip);
error = 0;
return error;
}
/**
* dump_inode - print information about an inode
* @ip: the inode
*
* Returns: 0 on success, -ENOBUFS when we run out of space
*/
static int dump_inode(struct gfs2_inode *ip)
{
unsigned int x;
int error = -ENOBUFS;
printk(KERN_INFO " Inode:\n");
printk(KERN_INFO " num = %llu %llu\n",
ip->i_num.no_formal_ino, ip->i_num.no_addr);
printk(KERN_INFO " type = %u\n", IF2DT(ip->i_di.di_mode));
printk(KERN_INFO " i_count = %d\n", atomic_read(&ip->i_count));
printk(KERN_INFO " i_flags =");
for (x = 0; x < 32; x++)
if (test_bit(x, &ip->i_flags))
printk(" %u", x);
printk(" \n");
printk(KERN_INFO " vnode = %s\n", (ip->i_vnode) ? "yes" : "no");
error = 0;
return error;
}
/**
* dump_glock - print information about a glock
* @gl: the glock
* @count: where we are in the buffer
*
* Returns: 0 on success, -ENOBUFS when we run out of space
*/
static int dump_glock(struct gfs2_glock *gl)
{
struct gfs2_holder *gh;
unsigned int x;
int error = -ENOBUFS;
spin_lock(&gl->gl_spin);
printk(KERN_INFO "Glock (%u, %llu)\n",
gl->gl_name.ln_type,
gl->gl_name.ln_number);
printk(KERN_INFO " gl_flags =");
for (x = 0; x < 32; x++)
if (test_bit(x, &gl->gl_flags))
printk(" %u", x);
printk(" \n");
printk(KERN_INFO " gl_ref = %d\n", atomic_read(&gl->gl_ref.refcount));
printk(KERN_INFO " gl_state = %u\n", gl->gl_state);
printk(KERN_INFO " req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
printk(KERN_INFO " req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
printk(KERN_INFO " lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
printk(KERN_INFO " object = %s\n", (gl->gl_object) ? "yes" : "no");
printk(KERN_INFO " le = %s\n",
(list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
printk(KERN_INFO " reclaim = %s\n",
(list_empty(&gl->gl_reclaim)) ? "no" : "yes");
if (gl->gl_aspace)
printk(KERN_INFO " aspace = %lu\n",
gl->gl_aspace->i_mapping->nrpages);
else
printk(KERN_INFO " aspace = no\n");
printk(KERN_INFO " ail = %d\n", atomic_read(&gl->gl_ail_count));
if (gl->gl_req_gh) {
error = dump_holder("Request", gl->gl_req_gh);
if (error)
goto out;
}
list_for_each_entry(gh, &gl->gl_holders, gh_list) {
error = dump_holder("Holder", gh);
if (error)
goto out;
}
list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
error = dump_holder("Waiter1", gh);
if (error)
goto out;
}
list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
error = dump_holder("Waiter2", gh);
if (error)
goto out;
}
list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
error = dump_holder("Waiter3", gh);
if (error)
goto out;
}
if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
list_empty(&gl->gl_holders)) {
error = dump_inode(gl->gl_object);
if (error)
goto out;
} else {
error = -ENOBUFS;
printk(KERN_INFO " Inode: busy\n");
}
}
error = 0;
out:
spin_unlock(&gl->gl_spin);
return error;
}
/**
* gfs2_dump_lockstate - print out the current lockstate
* @sdp: the filesystem
* @ub: the buffer to copy the information into
*
* If @ub is NULL, dump the lockstate to the console.
*
*/
int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
{
struct gfs2_gl_hash_bucket *bucket;
struct gfs2_glock *gl;
unsigned int x;
int error = 0;
for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
bucket = &sdp->sd_gl_hash[x];
read_lock(&bucket->hb_lock);
list_for_each_entry(gl, &bucket->hb_list, gl_list) {
if (test_bit(GLF_PLUG, &gl->gl_flags))
continue;
error = dump_glock(gl);
if (error)
break;
}
read_unlock(&bucket->hb_lock);
if (error)
break;
}
return error;
}
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