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kernel-fxtec-pro1x/fs/gfs2/glock.c
Steven Whitehouse 190562bd84 [GFS2] Fix a bug: scheduling under a spinlock 
At some stage, a mutex was added to gfs2_glock_put() without
checking all its call sites. Two of them were called from
under a spinlock causing random delays at various points and
crashes.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-04-20 16:57:23 -04:00

2493 lines
55 KiB
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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)
{
flags |= GL_NEVER_RECURSE;
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 | GL_NEVER_RECURSE;
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);
}
/**
* handle_recurse - put other holder structures (marked recursive)
* into the holders list
* @gh: the holder structure
*
*/
static void handle_recurse(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_holder *tmp_gh, *safe;
int found = 0;
BUG_ON(!spin_is_locked(&gl->gl_spin));
printk(KERN_INFO "recursion %016llx, %u\n", gl->gl_name.ln_number,
gl->gl_name.ln_type);
if (gfs2_assert_warn(sdp, gh->gh_owner))
return;
list_for_each_entry_safe(tmp_gh, safe, &gl->gl_waiters3, gh_list) {
if (tmp_gh->gh_owner != gh->gh_owner)
continue;
gfs2_assert_warn(sdp,
test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
list_move_tail(&tmp_gh->gh_list, &gl->gl_holders);
tmp_gh->gh_error = 0;
set_bit(HIF_HOLDER, &tmp_gh->gh_iflags);
complete(&tmp_gh->gh_wait);
found = 1;
}
gfs2_assert_warn(sdp, found);
}
/**
* do_unrecurse - a recursive holder was just dropped of the waiters3 list
* @gh: the holder
*
* If there is only one other recursive holder, clear its HIF_RECURSE bit.
* If there is more than one, leave them alone.
*
*/
static void do_unrecurse(struct gfs2_holder *gh)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_holder *tmp_gh, *last_gh = NULL;
int found = 0;
BUG_ON(!spin_is_locked(&gl->gl_spin));
if (gfs2_assert_warn(sdp, gh->gh_owner))
return;
list_for_each_entry(tmp_gh, &gl->gl_waiters3, gh_list) {
if (tmp_gh->gh_owner != gh->gh_owner)
continue;
gfs2_assert_warn(sdp,
test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
if (found)
return;
found = 1;
last_gh = tmp_gh;
}
if (!gfs2_assert_warn(sdp, found))
clear_bit(HIF_RECURSE, &last_gh->gh_iflags);
}
/**
* 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;
int recurse;
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);
recurse = 0;
} 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;
recurse = test_bit(HIF_RECURSE, &gh->gh_iflags);
}
list_move_tail(&gh->gh_list, &gl->gl_holders);
gh->gh_error = 0;
set_bit(HIF_HOLDER, &gh->gh_iflags);
if (recurse)
handle_recurse(gh);
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 | GL_NEVER_RECURSE,
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;
if (test_bit(HIF_RECURSE, &gh->gh_iflags))
do_unrecurse(gh);
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;
if (test_bit(HIF_RECURSE, &gh->gh_iflags))
do_unrecurse(gh);
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;
if (test_bit(HIF_RECURSE, &gh->gh_iflags))
do_unrecurse(gh);
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;
if (test_bit(HIF_RECURSE, &gh->gh_iflags))
do_unrecurse(gh);
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);
if (test_and_clear_bit(HIF_RECURSE,
&gh->gh_iflags))
do_unrecurse(gh);
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);
if (test_bit(HIF_RECURSE, &gh->gh_iflags))
handle_recurse(gh);
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;
}
/**
* recurse_check -
*
* Make sure the new holder is compatible with the pre-existing one.
*
*/
static int recurse_check(struct gfs2_holder *existing, struct gfs2_holder *new,
unsigned int state)
{
struct gfs2_sbd *sdp = existing->gh_gl->gl_sbd;
if (gfs2_assert_warn(sdp, (new->gh_flags & LM_FLAG_ANY) ||
!(existing->gh_flags & LM_FLAG_ANY)))
goto fail;
if (gfs2_assert_warn(sdp, (existing->gh_flags & GL_LOCAL_EXCL) ||
!(new->gh_flags & GL_LOCAL_EXCL)))
goto fail;
if (gfs2_assert_warn(sdp, relaxed_state_ok(state, new->gh_state,
new->gh_flags)))
goto fail;
return 0;
fail:
print_symbol(KERN_WARNING "GFS2: Existing holder from %s\n",
existing->gh_ip);
print_symbol(KERN_WARNING "GFS2: New holder from %s\n", new->gh_ip);
set_bit(HIF_ABORTED, &new->gh_iflags);
return -EINVAL;
}
/**
* 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);
if (!gh->gh_owner)
goto out;
existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
if (existing) {
if (recurse_check(existing, gh, gl->gl_state))
return;
list_add_tail(&gh->gh_list, &gl->gl_holders);
set_bit(HIF_HOLDER, &gh->gh_iflags);
gh->gh_error = 0;
complete(&gh->gh_wait);
return;
}
existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
if (existing) {
if (recurse_check(existing, gh, existing->gh_state))
return;
set_bit(HIF_RECURSE, &gh->gh_iflags);
set_bit(HIF_RECURSE, &existing->gh_iflags);
list_add_tail(&gh->gh_list, &gl->gl_waiters3);
return;
}
out:
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, GL_NEVER_RECURSE, &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 = (struct greedy *)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, GL_NEVER_RECURSE, 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, (struct lm_lockname *)data, LM_ST_UNLOCKED);
return;
case LM_CB_NEED_D:
blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_DEFERRED);
return;
case LM_CB_NEED_S:
blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_SHARED);
return;
case LM_CB_ASYNC: {
struct lm_async_cb *async = (struct lm_async_cb *)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);
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);
}
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);
}
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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