Release 4.10 fs/dlm/lock.c
/******************************************************************************
*******************************************************************************
**
** Copyright (C) 2005-2010 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.
**
*******************************************************************************
******************************************************************************/
/* Central locking logic has four stages:
dlm_lock()
dlm_unlock()
request_lock(ls, lkb)
convert_lock(ls, lkb)
unlock_lock(ls, lkb)
cancel_lock(ls, lkb)
_request_lock(r, lkb)
_convert_lock(r, lkb)
_unlock_lock(r, lkb)
_cancel_lock(r, lkb)
do_request(r, lkb)
do_convert(r, lkb)
do_unlock(r, lkb)
do_cancel(r, lkb)
Stage 1 (lock, unlock) is mainly about checking input args and
splitting into one of the four main operations:
dlm_lock = request_lock
dlm_lock+CONVERT = convert_lock
dlm_unlock = unlock_lock
dlm_unlock+CANCEL = cancel_lock
Stage 2, xxxx_lock(), just finds and locks the relevant rsb which is
provided to the next stage.
Stage 3, _xxxx_lock(), determines if the operation is local or remote.
When remote, it calls send_xxxx(), when local it calls do_xxxx().
Stage 4, do_xxxx(), is the guts of the operation. It manipulates the
given rsb and lkb and queues callbacks.
For remote operations, send_xxxx() results in the corresponding do_xxxx()
function being executed on the remote node. The connecting send/receive
calls on local (L) and remote (R) nodes:
L: send_xxxx() -> R: receive_xxxx()
R: do_xxxx()
L: receive_xxxx_reply() <- R: send_xxxx_reply()
*/
#include <linux/types.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include "dlm_internal.h"
#include <linux/dlm_device.h>
#include "memory.h"
#include "lowcomms.h"
#include "requestqueue.h"
#include "util.h"
#include "dir.h"
#include "member.h"
#include "lockspace.h"
#include "ast.h"
#include "lock.h"
#include "rcom.h"
#include "recover.h"
#include "lvb_table.h"
#include "user.h"
#include "config.h"
static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode);
static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int send_remove(struct dlm_rsb *r);
static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
struct dlm_message *ms);
static int receive_extralen(struct dlm_message *ms);
static void do_purge(struct dlm_ls *ls, int nodeid, int pid);
static void del_timeout(struct dlm_lkb *lkb);
static void toss_rsb(struct kref *kref);
/*
* Lock compatibilty matrix - thanks Steve
* UN = Unlocked state. Not really a state, used as a flag
* PD = Padding. Used to make the matrix a nice power of two in size
* Other states are the same as the VMS DLM.
* Usage: matrix[grmode+1][rqmode+1] (although m[rq+1][gr+1] is the same)
*/
static const int __dlm_compat_matrix[8][8] = {
/* UN NL CR CW PR PW EX PD */
{1, 1, 1, 1, 1, 1, 1, 0}, /* UN */
{1, 1, 1, 1, 1, 1, 1, 0}, /* NL */
{1, 1, 1, 1, 1, 1, 0, 0}, /* CR */
{1, 1, 1, 1, 0, 0, 0, 0}, /* CW */
{1, 1, 1, 0, 1, 0, 0, 0}, /* PR */
{1, 1, 1, 0, 0, 0, 0, 0}, /* PW */
{1, 1, 0, 0, 0, 0, 0, 0}, /* EX */
{0, 0, 0, 0, 0, 0, 0, 0} /* PD */
};
/*
* This defines the direction of transfer of LVB data.
* Granted mode is the row; requested mode is the column.
* Usage: matrix[grmode+1][rqmode+1]
* 1 = LVB is returned to the caller
* 0 = LVB is written to the resource
* -1 = nothing happens to the LVB
*/
const int dlm_lvb_operations[8][8] = {
/* UN NL CR CW PR PW EX PD*/
{ -1, 1, 1, 1, 1, 1, 1, -1 }, /* UN */
{ -1, 1, 1, 1, 1, 1, 1, 0 }, /* NL */
{ -1, -1, 1, 1, 1, 1, 1, 0 }, /* CR */
{ -1, -1, -1, 1, 1, 1, 1, 0 }, /* CW */
{ -1, -1, -1, -1, 1, 1, 1, 0 }, /* PR */
{ -1, 0, 0, 0, 0, 0, 1, 0 }, /* PW */
{ -1, 0, 0, 0, 0, 0, 0, 0 }, /* EX */
{ -1, 0, 0, 0, 0, 0, 0, 0 } /* PD */
};
#define modes_compat(gr, rq) \
__dlm_compat_matrix[(gr)->lkb_grmode + 1][(rq)->lkb_rqmode + 1]
int dlm_modes_compat(int mode1, int mode2)
{
return __dlm_compat_matrix[mode1 + 1][mode2 + 1];
}
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/*
* Compatibility matrix for conversions with QUECVT set.
* Granted mode is the row; requested mode is the column.
* Usage: matrix[grmode+1][rqmode+1]
*/
static const int __quecvt_compat_matrix[8][8] = {
/* UN NL CR CW PR PW EX PD */
{0, 0, 0, 0, 0, 0, 0, 0}, /* UN */
{0, 0, 1, 1, 1, 1, 1, 0}, /* NL */
{0, 0, 0, 1, 1, 1, 1, 0}, /* CR */
{0, 0, 0, 0, 1, 1, 1, 0}, /* CW */
{0, 0, 0, 1, 0, 1, 1, 0}, /* PR */
{0, 0, 0, 0, 0, 0, 1, 0}, /* PW */
{0, 0, 0, 0, 0, 0, 0, 0}, /* EX */
{0, 0, 0, 0, 0, 0, 0, 0} /* PD */
};
void dlm_print_lkb(struct dlm_lkb *lkb)
{
printk(KERN_ERR "lkb: nodeid %d id %x remid %x exflags %x flags %x "
"sts %d rq %d gr %d wait_type %d wait_nodeid %d seq %llu\n",
lkb->lkb_nodeid, lkb->lkb_id, lkb->lkb_remid, lkb->lkb_exflags,
lkb->lkb_flags, lkb->lkb_status, lkb->lkb_rqmode,
lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_wait_nodeid,
(unsigned long long)lkb->lkb_recover_seq);
}
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static void dlm_print_rsb(struct dlm_rsb *r)
{
printk(KERN_ERR "rsb: nodeid %d master %d dir %d flags %lx first %x "
"rlc %d name %s\n",
r->res_nodeid, r->res_master_nodeid, r->res_dir_nodeid,
r->res_flags, r->res_first_lkid, r->res_recover_locks_count,
r->res_name);
}
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void dlm_dump_rsb(struct dlm_rsb *r)
{
struct dlm_lkb *lkb;
dlm_print_rsb(r);
printk(KERN_ERR "rsb: root_list empty %d recover_list empty %d\n",
list_empty(&r->res_root_list), list_empty(&r->res_recover_list));
printk(KERN_ERR "rsb lookup list\n");
list_for_each_entry(lkb, &r->res_lookup, lkb_rsb_lookup)
dlm_print_lkb(lkb);
printk(KERN_ERR "rsb grant queue:\n");
list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue)
dlm_print_lkb(lkb);
printk(KERN_ERR "rsb convert queue:\n");
list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue)
dlm_print_lkb(lkb);
printk(KERN_ERR "rsb wait queue:\n");
list_for_each_entry(lkb, &r->res_waitqueue, lkb_statequeue)
dlm_print_lkb(lkb);
}
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/* Threads cannot use the lockspace while it's being recovered */
static inline void dlm_lock_recovery(struct dlm_ls *ls)
{
down_read(&ls->ls_in_recovery);
}
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void dlm_unlock_recovery(struct dlm_ls *ls)
{
up_read(&ls->ls_in_recovery);
}
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int dlm_lock_recovery_try(struct dlm_ls *ls)
{
return down_read_trylock(&ls->ls_in_recovery);
}
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static inline int can_be_queued(struct dlm_lkb *lkb)
{
return !(lkb->lkb_exflags & DLM_LKF_NOQUEUE);
}
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static inline int force_blocking_asts(struct dlm_lkb *lkb)
{
return (lkb->lkb_exflags & DLM_LKF_NOQUEUEBAST);
}
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static inline int is_demoted(struct dlm_lkb *lkb)
{
return (lkb->lkb_sbflags & DLM_SBF_DEMOTED);
}
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static inline int is_altmode(struct dlm_lkb *lkb)
{
return (lkb->lkb_sbflags & DLM_SBF_ALTMODE);
}
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static inline int is_granted(struct dlm_lkb *lkb)
{
return (lkb->lkb_status == DLM_LKSTS_GRANTED);
}
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static inline int is_remote(struct dlm_rsb *r)
{
DLM_ASSERT(r->res_nodeid >= 0, dlm_print_rsb(r););
return !!r->res_nodeid;
}
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static inline int is_process_copy(struct dlm_lkb *lkb)
{
return (lkb->lkb_nodeid && !(lkb->lkb_flags & DLM_IFL_MSTCPY));
}
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static inline int is_master_copy(struct dlm_lkb *lkb)
{
return (lkb->lkb_flags & DLM_IFL_MSTCPY) ? 1 : 0;
}
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static inline int middle_conversion(struct dlm_lkb *lkb)
{
if ((lkb->lkb_grmode==DLM_LOCK_PR && lkb->lkb_rqmode==DLM_LOCK_CW) ||
(lkb->lkb_rqmode==DLM_LOCK_PR && lkb->lkb_grmode==DLM_LOCK_CW))
return 1;
return 0;
}
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static inline int down_conversion(struct dlm_lkb *lkb)
{
return (!middle_conversion(lkb) && lkb->lkb_rqmode < lkb->lkb_grmode);
}
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static inline int is_overlap_unlock(struct dlm_lkb *lkb)
{
return lkb->lkb_flags & DLM_IFL_OVERLAP_UNLOCK;
}
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static inline int is_overlap_cancel(struct dlm_lkb *lkb)
{
return lkb->lkb_flags & DLM_IFL_OVERLAP_CANCEL;
}
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static inline int is_overlap(struct dlm_lkb *lkb)
{
return (lkb->lkb_flags & (DLM_IFL_OVERLAP_UNLOCK |
DLM_IFL_OVERLAP_CANCEL));
}
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static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
{
if (is_master_copy(lkb))
return;
del_timeout(lkb);
DLM_ASSERT(lkb->lkb_lksb, dlm_print_lkb(lkb););
/* if the operation was a cancel, then return -DLM_ECANCEL, if a
timeout caused the cancel then return -ETIMEDOUT */
if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_TIMEOUT_CANCEL)) {
lkb->lkb_flags &= ~DLM_IFL_TIMEOUT_CANCEL;
rv = -ETIMEDOUT;
}
if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_DEADLOCK_CANCEL)) {
lkb->lkb_flags &= ~DLM_IFL_DEADLOCK_CANCEL;
rv = -EDEADLK;
}
dlm_add_cb(lkb, DLM_CB_CAST, lkb->lkb_grmode, rv, lkb->lkb_sbflags);
}
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static inline void queue_cast_overlap(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
queue_cast(r, lkb,
is_overlap_unlock(lkb) ? -DLM_EUNLOCK : -DLM_ECANCEL);
}
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static void queue_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rqmode)
{
if (is_master_copy(lkb)) {
send_bast(r, lkb, rqmode);
} else {
dlm_add_cb(lkb, DLM_CB_BAST, rqmode, 0, 0);
}
}
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/*
* Basic operations on rsb's and lkb's
*/
/* This is only called to add a reference when the code already holds
a valid reference to the rsb, so there's no need for locking. */
static inline void hold_rsb(struct dlm_rsb *r)
{
kref_get(&r->res_ref);
}
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void dlm_hold_rsb(struct dlm_rsb *r)
{
hold_rsb(r);
}
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/* When all references to the rsb are gone it's transferred to
the tossed list for later disposal. */
static void put_rsb(struct dlm_rsb *r)
{
struct dlm_ls *ls = r->res_ls;
uint32_t bucket = r->res_bucket;
spin_lock(&ls->ls_rsbtbl[bucket].lock);
kref_put(&r->res_ref, toss_rsb);
spin_unlock(&ls->ls_rsbtbl[bucket].lock);
}
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void dlm_put_rsb(struct dlm_rsb *r)
{
put_rsb(r);
}
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static int pre_rsb_struct(struct dlm_ls *ls)
{
struct dlm_rsb *r1, *r2;
int count = 0;
spin_lock(&ls->ls_new_rsb_spin);
if (ls->ls_new_rsb_count > dlm_config.ci_new_rsb_count / 2) {
spin_unlock(&ls->ls_new_rsb_spin);
return 0;
}
spin_unlock(&ls->ls_new_rsb_spin);
r1 = dlm_allocate_rsb(ls);
r2 = dlm_allocate_rsb(ls);
spin_lock(&ls->ls_new_rsb_spin);
if (r1) {
list_add(&r1->res_hashchain, &ls->ls_new_rsb);
ls->ls_new_rsb_count++;
}
if (r2) {
list_add(&r2->res_hashchain, &ls->ls_new_rsb);
ls->ls_new_rsb_count++;
}
count = ls->ls_new_rsb_count;
spin_unlock(&ls->ls_new_rsb_spin);
if (!count)
return -ENOMEM;
return 0;
}
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/* If ls->ls_new_rsb is empty, return -EAGAIN, so the caller can
unlock any spinlocks, go back and call pre_rsb_struct again.
Otherwise, take an rsb off the list and return it. */
static int get_rsb_struct(struct dlm_ls *ls, char *name, int len,
struct dlm_rsb **r_ret)
{
struct dlm_rsb *r;
int count;
spin_lock(&ls->ls_new_rsb_spin);
if (list_empty(&ls->ls_new_rsb)) {
count = ls->ls_new_rsb_count;
spin_unlock(&ls->ls_new_rsb_spin);
log_debug(ls, "find_rsb retry %d %d %s",
count, dlm_config.ci_new_rsb_count, name);
return -EAGAIN;
}
r = list_first_entry(&ls->ls_new_rsb, struct dlm_rsb, res_hashchain);
list_del(&r->res_hashchain);
/* Convert the empty list_head to a NULL rb_node for tree usage: */
memset(&r->res_hashnode, 0, sizeof(struct rb_node));
ls->ls_new_rsb_count--;
spin_unlock(&ls->ls_new_rsb_spin);
r->res_ls = ls;
r->res_length = len;
memcpy(r->res_name, name, len);
mutex_init(&r->res_mutex);
INIT_LIST_HEAD(&r->res_lookup);
INIT_LIST_HEAD(&r->res_grantqueue);
INIT_LIST_HEAD(&r->res_convertqueue);
INIT_LIST_HEAD(&r->res_waitqueue);
INIT_LIST_HEAD(&r->res_root_list);
INIT_LIST_HEAD(&r->res_recover_list);
*r_ret = r;
return 0;
}
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static int rsb_cmp(struct dlm_rsb *r, const char *name, int nlen)
{
char maxname[DLM_RESNAME_MAXLEN];
memset(maxname, 0, DLM_RESNAME_MAXLEN);
memcpy(maxname, name, nlen);
return memcmp(r->res_name, maxname, DLM_RESNAME_MAXLEN);
}
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int dlm_search_rsb_tree(struct rb_root *tree, char *name, int len,
struct dlm_rsb **r_ret)
{
struct rb_node *node = tree->rb_node;
struct dlm_rsb *r;
int rc;
while (node) {
r = rb_entry(node, struct dlm_rsb, res_hashnode);
rc = rsb_cmp(r, name, len);
if (rc < 0)
node = node->rb_left;
else if (rc > 0)
node = node->rb_right;
else
goto found;
}
*r_ret = NULL;
return -EBADR;
found:
*r_ret = r;
return 0;
}
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static int rsb_insert(struct dlm_rsb *rsb, struct rb_root *tree)
{
struct rb_node **newn = &tree->rb_node;
struct rb_node *parent = NULL;
int rc;
while (*newn) {
struct dlm_rsb *cur = rb_entry(*newn, struct dlm_rsb,
res_hashnode);
parent = *newn;
rc = rsb_cmp(cur, rsb->res_name, rsb->res_length);
if (rc < 0)
newn = &parent->rb_left;
else if (rc > 0)
newn = &parent->rb_right;
else {
log_print("rsb_insert match");
dlm_dump_rsb(rsb);
dlm_dump_rsb(cur);
return -EEXIST;
}
}
rb_link_node(&rsb->res_hashnode, parent, newn);
rb_insert_color(&rsb->res_hashnode, tree);
return 0;
}
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| Person | Tokens | Prop | Commits | CommitProp |
| robert s. peterson | robert s. peterson | 154 | 100.00% | 1 | 100.00% |
| Total | 154 | 100.00% | 1 | 100.00% |
/*
* Find rsb in rsbtbl and potentially create/add one
*
* Delaying the release of rsb's has a similar benefit to applications keeping
* NL locks on an rsb, but without the guarantee that the cached master value
* will still be valid when the rsb is reused. Apps aren't always smart enough
* to keep NL locks on an rsb that they may lock again shortly; this can lead
* to excessive master lookups and removals if we don't delay the release.
*
* Searching for an rsb means looking through both the normal list and toss
* list. When found on the toss list the rsb is moved to the normal list with
* ref count of 1; when found on normal list the ref count is incremented.
*
* rsb's on the keep list are being used locally and refcounted.
* rsb's on the toss list are not being used locally, and are not refcounted.
*
* The toss list rsb's were either
* - previously used locally but not any more (were on keep list, then
* moved to toss list when last refcount dropped)
* - created and put on toss list as a directory record for a lookup
* (we are the dir node for the res, but are not using the res right now,
* but some other node is)
*
* The purpose of find_rsb() is to return a refcounted rsb for local use.
* So, if the given rsb is on the toss list, it is moved to the keep list
* before being returned.
*
* toss_rsb() happens when all local usage of the rsb is done, i.e. no
* more refcounts exist, so the rsb is moved from the keep list to the
* toss list.
*
* rsb's on both keep and toss lists are used for doing a name to master
* lookups. rsb's that are in use locally (and being refcounted) are on
* the keep list, rsb's that are not in use locally (not refcounted) and
* only exist for name/master lookups are on the toss list.
*
* rsb's on the toss list who's dir_nodeid is not local can have stale
* name/master mappings. So, remote requests on such rsb's can potentially
* return with an error, which means the mapping is stale and needs to
* be updated with a new lookup. (The idea behind MASTER UNCERTAIN and
* first_lkid is to keep only a single outstanding request on an rsb
* while that rsb has a potentially stale master.)
*/
static int find_rsb_dir(struct dlm_ls *ls, char *name, int len,
uint32_t hash, uint32_t b,
int dir_nodeid, int from_nodeid,
unsigned int flags, struct dlm_rsb **r_ret)
{
struct dlm_rsb *r = NULL;
int our_nodeid = dlm_our_nodeid();
int from_local = 0;
int from_other = 0;
int from_dir = 0;
int create = 0;
int error;
if (flags & R_RECEIVE_REQUEST) {
if (from_nodeid == dir_nodeid)
from_dir = 1;
else
from_other = 1;
} else if (flags & R_REQUEST) {
from_local = 1;
}
/*
* flags & R_RECEIVE_RECOVER is from dlm_recover_master_copy, so
* from_nodeid has sent us a lock in dlm_recover_locks, believing
* we're the new master. Our local recovery may not have set
* res_master_nodeid to our_nodeid yet, so allow either. Don't
* create the rsb; dlm_recover_process_copy() will handle EBADR
* by resending.
*
* If someone sends us a request, we are the dir node, and we do
* not find the rsb anywhere, then recreate it. This happens if
* someone sends us a request after we have removed/freed an rsb
* from our toss list. (They sent a request instead of lookup
* because they are using an rsb from their toss list.)
*/
if (from_local || from_dir ||
(from_other && (dir_nodeid == our_nodeid))) {
create = 1;
}
retry:
if (create) {
error = pre_rsb_struct(ls);
if (error < 0)
goto out;
}
spin_lock(&ls->ls_rsbtbl[b].lock);
error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].keep, name, len, &r);
if (error)
goto do_toss;
/*
* rsb is active, so we can't check master_nodeid without lock_rsb.
*/
kref_get(&r->res_ref);
error = 0;
goto out_unlock;
do_toss:
error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, &r);
if (error)
goto do_new;
/*
* rsb found inactive (master_nodeid may be out of date unless
* we are the dir_nodeid or were the master) No other thread
* is using this rsb because it's on the toss list, so we can
* look at or update res_master_nodeid without lock_rsb.
*/
if ((r->res_master_nodeid != our_nodeid) && from_other) {
/* our rsb was not master, and another node (not the dir node)
has sent us a request */
log_debug(ls, "find_rsb toss from_other %d master %d dir %d %s",
from_nodeid, r->res_master_nodeid, dir_nodeid,
r->res_name);
error = -ENOTBLK;
goto out_unlock;
}
if ((r->res_master_nodeid != our_nodeid) && from_dir) {
/* don't think this should ever happen */
log_error(ls, "find_rsb toss from_dir %d master %d",
from_nodeid, r->res_master_nodeid);
dlm_print_rsb(r);
/* fix it and go on */
r->res_master_nodeid = our_nodeid;
r->res_nodeid = 0;
rsb_clear_flag(r, RSB_MASTER_UNCERTAIN);
r->res_first_lkid = 0;
}
if (from_local && (r->res_master_nodeid != our_nodeid)) {
/* Because we have held no locks on this rsb,
res_master_nodeid could have become stale. */
rsb_set_flag(r, RSB_MASTER_UNCERTAIN);
r->res_first_lkid = 0;
}
rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
error = rsb_insert(r, &ls->ls_rsbtbl[b].keep);
goto out_unlock;
do_new:
/*
* rsb not found
*/
if (error == -EBADR && !create)
goto out_unlock;
error = get_rsb_struct(ls, name, len, &r);
if (error == -EAGAIN) {
spin_unlock(&ls->ls_rsbtbl[b].lock);
goto retry;
}
if (error)
goto out_unlock;
r->res_hash = hash;
r->res_bucket = b;
r->res_dir_nodeid = dir_nodeid;
kref_init(&r->res_ref);
if (from_dir) {