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glock.c
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glock.c
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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 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 version 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/kallsyms.h>
#include <linux/gfs2_ondisk.h>
#include <linux/list.h>
#include <linux/lm_interface.h>
#include <linux/wait.h>
#include <linux/module.h>
#include <linux/rwsem.h>
#include <asm/uaccess.h>
#include "gfs2.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"
struct gfs2_gl_hash_bucket {
struct hlist_head hb_list;
};
typedef void (*glock_examiner) (struct gfs2_glock * gl);
static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
static int dump_glock(struct gfs2_glock *gl);
static int dump_inode(struct gfs2_inode *ip);
static void gfs2_glock_xmote_th(struct gfs2_holder *gh);
static void gfs2_glock_drop_th(struct gfs2_glock *gl);
static DECLARE_RWSEM(gfs2_umount_flush_sem);
#define GFS2_GL_HASH_SHIFT 15
#define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT)
#define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1)
static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];
/*
* Despite what you might think, the numbers below are not arbitrary :-)
* They are taken from the ipv4 routing hash code, which is well tested
* and thus should be nearly optimal. Later on we might tweek the numbers
* but for now this should be fine.
*
* The reason for putting the locks in a separate array from the list heads
* is that we can have fewer locks than list heads and save memory. We use
* the same hash function for both, but with a different hash mask.
*/
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
defined(CONFIG_PROVE_LOCKING)
#ifdef CONFIG_LOCKDEP
# define GL_HASH_LOCK_SZ 256
#else
# if NR_CPUS >= 32
# define GL_HASH_LOCK_SZ 4096
# elif NR_CPUS >= 16
# define GL_HASH_LOCK_SZ 2048
# elif NR_CPUS >= 8
# define GL_HASH_LOCK_SZ 1024
# elif NR_CPUS >= 4
# define GL_HASH_LOCK_SZ 512
# else
# define GL_HASH_LOCK_SZ 256
# endif
#endif
/* We never want more locks than chains */
#if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ
# undef GL_HASH_LOCK_SZ
# define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE
#endif
static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ];
static inline rwlock_t *gl_lock_addr(unsigned int x)
{
return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)];
}
#else /* not SMP, so no spinlocks required */
static inline rwlock_t *gl_lock_addr(unsigned int x)
{
return NULL;
}
#endif
/**
* 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(const struct gfs2_sbd *sdp,
const struct lm_lockname *name)
{
unsigned int h;
h = jhash(&name->ln_number, sizeof(u64), 0);
h = jhash(&name->ln_type, sizeof(unsigned int), h);
h = jhash(&sdp, sizeof(struct gfs2_sbd *), 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)
{
atomic_inc(&gl->gl_ref);
}
/**
* gfs2_glock_put() - Decrement reference count on glock
* @gl: The glock to put
*
*/
int gfs2_glock_put(struct gfs2_glock *gl)
{
int rv = 0;
struct gfs2_sbd *sdp = gl->gl_sbd;
write_lock(gl_lock_addr(gl->gl_hash));
if (atomic_dec_and_test(&gl->gl_ref)) {
hlist_del(&gl->gl_list);
write_unlock(gl_lock_addr(gl->gl_hash));
BUG_ON(spin_is_locked(&gl->gl_spin));
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));
glock_free(gl);
rv = 1;
goto out;
}
write_unlock(gl_lock_addr(gl->gl_hash));
out:
return rv;
}
/**
* 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(unsigned int hash,
const struct gfs2_sbd *sdp,
const struct lm_lockname *name)
{
struct gfs2_glock *gl;
struct hlist_node *h;
hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, gl_list) {
if (!lm_name_equal(&gl->gl_name, name))
continue;
if (gl->gl_sbd != sdp)
continue;
atomic_inc(&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
*/
static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
const struct lm_lockname *name)
{
unsigned int hash = gl_hash(sdp, name);
struct gfs2_glock *gl;
read_lock(gl_lock_addr(hash));
gl = search_bucket(hash, sdp, name);
read_unlock(gl_lock_addr(hash));
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 };
struct gfs2_glock *gl, *tmp;
unsigned int hash = gl_hash(sdp, &name);
int error;
read_lock(gl_lock_addr(hash));
gl = search_bucket(hash, sdp, &name);
read_unlock(gl_lock_addr(hash));
if (gl || !create) {
*glp = gl;
return 0;
}
gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
if (!gl)
return -ENOMEM;
gl->gl_flags = 0;
gl->gl_name = name;
atomic_set(&gl->gl_ref, 1);
gl->gl_state = LM_ST_UNLOCKED;
gl->gl_hash = hash;
gl->gl_owner = NULL;
gl->gl_ip = 0;
gl->gl_ops = glops;
gl->gl_req_gh = NULL;
gl->gl_req_bh = NULL;
gl->gl_vn = 0;
gl->gl_stamp = jiffies;
gl->gl_object = NULL;
gl->gl_sbd = sdp;
gl->gl_aspace = NULL;
lops_init_le(&gl->gl_le, &gfs2_glock_lops);
/* 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) {
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(gl_lock_addr(hash));
tmp = search_bucket(hash, sdp, &name);
if (tmp) {
write_unlock(gl_lock_addr(hash));
glock_free(gl);
gl = tmp;
} else {
hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list);
write_unlock(gl_lock_addr(hash));
}
*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;
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;
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:
*
* 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
*/
static 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
*
*/
static void gfs2_holder_put(struct gfs2_holder *gh)
{
gfs2_holder_uninit(gh);
kfree(gh);
}
static void gfs2_holder_dispose_or_wake(struct gfs2_holder *gh)
{
if (test_bit(HIF_DEALLOC, &gh->gh_iflags)) {
gfs2_holder_put(gh);
return;
}
clear_bit(HIF_WAIT, &gh->gh_iflags);
smp_mb();
wake_up_bit(&gh->gh_iflags, HIF_WAIT);
}
static int holder_wait(void *word)
{
schedule();
return 0;
}
static void wait_on_holder(struct gfs2_holder *gh)
{
might_sleep();
wait_on_bit(&gh->gh_iflags, HIF_WAIT, holder_wait, TASK_UNINTERRUPTIBLE);
}
/**
* 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);
clear_bit(HIF_WAIT, &gh->gh_iflags);
smp_mb();
wake_up_bit(&gh->gh_iflags, HIF_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;
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);
}
gfs2_glock_xmote_th(gh);
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_state == LM_ST_EXCLUSIVE)
return 1;
next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
gh_list);
if (next_gh->gh_state == LM_ST_EXCLUSIVE)
return 1;
}
list_move_tail(&gh->gh_list, &gl->gl_holders);
gh->gh_error = 0;
set_bit(HIF_HOLDER, &gh->gh_iflags);
gfs2_holder_dispose_or_wake(gh);
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;
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);
gfs2_holder_dispose_or_wake(gh);
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)
gfs2_glock_drop_th(gl);
else
gfs2_glock_xmote_th(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
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.
*/
static 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);
if (test_and_set_bit(HIF_WAIT, &gh.gh_iflags))
BUG();
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 {
gl->gl_owner = current;
gl->gl_ip = (unsigned long)__builtin_return_address(0);
clear_bit(HIF_WAIT, &gh.gh_iflags);
smp_mb();
wake_up_bit(&gh.gh_iflags, HIF_WAIT);
}
spin_unlock(&gl->gl_spin);
wait_on_holder(&gh);
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
*/
static 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;
} else {
gl->gl_owner = current;
gl->gl_ip = (unsigned long)__builtin_return_address(0);
}
spin_unlock(&gl->gl_spin);
return acquired;
}
/**
* gfs2_glmutex_unlock - release a local lock on a glock
* @gl: the glock
*
*/
static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
{
spin_lock(&gl->gl_spin);
clear_bit(GLF_LOCK, &gl->gl_flags);
gl->gl_owner = NULL;
gl->gl_ip = 0;
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
*
* Note: This may fail sliently if we are out of memory.
*/
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_NOFS);
if (!new_gh)
return;
set_bit(HIF_DEMOTE, &new_gh->gh_iflags);
set_bit(HIF_DEALLOC, &new_gh->gh_iflags);
set_bit(HIF_WAIT, &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;
const 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, list_empty(&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);
} 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, 0);
}
/* 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);
} 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)
gfs2_holder_dispose_or_wake(gh);
}
/**
* 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_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_sbd *sdp = gl->gl_sbd;
int flags = gh->gh_flags;
unsigned state = gh->gh_state;
const 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;
if (glops->go_xmote_th)
glops->go_xmote_th(gl);
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
gfs2_assert_warn(sdp, state != gl->gl_state);
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;
const struct gfs2_glock_operations *glops = gl->gl_ops;
struct gfs2_holder *gh = gl->gl_req_gh;
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
gfs2_assert_warn(sdp, !ret);
state_change(gl, LM_ST_UNLOCKED);
if (glops->go_inval)
glops->go_inval(gl, DIO_METADATA);
if (gh) {
spin_lock(&gl->gl_spin);
list_del_init(&gh->gh_list);
gh->gh_error = 0;
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);
gfs2_glock_put(gl);
if (gh)
gfs2_holder_dispose_or_wake(gh);
}
/**
* gfs2_glock_drop_th - call into the lock module to unlock a lock
* @gl: the glock
*
*/
static void gfs2_glock_drop_th(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
const struct gfs2_glock_operations *glops = gl->gl_ops;
unsigned int ret;
if (glops->go_drop_th)
glops->go_drop_th(gl);
gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
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);