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41d7db0ab4
This patch removes the completion (which is rather large) from struct gdlm_lock in favour of using the wait_on_bit() functions. We don't need to add any extra fields to the structure to do this, so we save 32 bytes (on x86_64) per structure. This adds up to quite a lot when we may potentially have millions of these lock structures, Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Acked-by: David Teigland <teigland@redhat.com>
528 lines
12 KiB
C
528 lines
12 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#include "lock_dlm.h"
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static char junk_lvb[GDLM_LVB_SIZE];
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static void queue_complete(struct gdlm_lock *lp)
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{
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struct gdlm_ls *ls = lp->ls;
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clear_bit(LFL_ACTIVE, &lp->flags);
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spin_lock(&ls->async_lock);
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list_add_tail(&lp->clist, &ls->complete);
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spin_unlock(&ls->async_lock);
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wake_up(&ls->thread_wait);
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}
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static inline void gdlm_ast(void *astarg)
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{
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queue_complete(astarg);
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}
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static inline void gdlm_bast(void *astarg, int mode)
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{
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struct gdlm_lock *lp = astarg;
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struct gdlm_ls *ls = lp->ls;
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if (!mode) {
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printk(KERN_INFO "lock_dlm: bast mode zero %x,%llx\n",
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lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number);
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return;
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}
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spin_lock(&ls->async_lock);
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if (!lp->bast_mode) {
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list_add_tail(&lp->blist, &ls->blocking);
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lp->bast_mode = mode;
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} else if (lp->bast_mode < mode)
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lp->bast_mode = mode;
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spin_unlock(&ls->async_lock);
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wake_up(&ls->thread_wait);
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}
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void gdlm_queue_delayed(struct gdlm_lock *lp)
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{
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struct gdlm_ls *ls = lp->ls;
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spin_lock(&ls->async_lock);
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list_add_tail(&lp->delay_list, &ls->delayed);
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spin_unlock(&ls->async_lock);
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}
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/* convert gfs lock-state to dlm lock-mode */
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static s16 make_mode(s16 lmstate)
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{
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switch (lmstate) {
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case LM_ST_UNLOCKED:
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return DLM_LOCK_NL;
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case LM_ST_EXCLUSIVE:
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return DLM_LOCK_EX;
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case LM_ST_DEFERRED:
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return DLM_LOCK_CW;
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case LM_ST_SHARED:
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return DLM_LOCK_PR;
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}
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gdlm_assert(0, "unknown LM state %d", lmstate);
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return -1;
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}
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/* convert dlm lock-mode to gfs lock-state */
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s16 gdlm_make_lmstate(s16 dlmmode)
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{
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switch (dlmmode) {
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case DLM_LOCK_IV:
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case DLM_LOCK_NL:
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return LM_ST_UNLOCKED;
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case DLM_LOCK_EX:
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return LM_ST_EXCLUSIVE;
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case DLM_LOCK_CW:
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return LM_ST_DEFERRED;
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case DLM_LOCK_PR:
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return LM_ST_SHARED;
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}
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gdlm_assert(0, "unknown DLM mode %d", dlmmode);
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return -1;
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}
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/* verify agreement with GFS on the current lock state, NB: DLM_LOCK_NL and
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DLM_LOCK_IV are both considered LM_ST_UNLOCKED by GFS. */
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static void check_cur_state(struct gdlm_lock *lp, unsigned int cur_state)
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{
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s16 cur = make_mode(cur_state);
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if (lp->cur != DLM_LOCK_IV)
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gdlm_assert(lp->cur == cur, "%d, %d", lp->cur, cur);
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}
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static inline unsigned int make_flags(struct gdlm_lock *lp,
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unsigned int gfs_flags,
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s16 cur, s16 req)
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{
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unsigned int lkf = 0;
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if (gfs_flags & LM_FLAG_TRY)
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lkf |= DLM_LKF_NOQUEUE;
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if (gfs_flags & LM_FLAG_TRY_1CB) {
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lkf |= DLM_LKF_NOQUEUE;
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lkf |= DLM_LKF_NOQUEUEBAST;
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}
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if (gfs_flags & LM_FLAG_PRIORITY) {
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lkf |= DLM_LKF_NOORDER;
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lkf |= DLM_LKF_HEADQUE;
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}
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if (gfs_flags & LM_FLAG_ANY) {
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if (req == DLM_LOCK_PR)
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lkf |= DLM_LKF_ALTCW;
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else if (req == DLM_LOCK_CW)
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lkf |= DLM_LKF_ALTPR;
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}
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if (lp->lksb.sb_lkid != 0) {
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lkf |= DLM_LKF_CONVERT;
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/* Conversion deadlock avoidance by DLM */
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if (!test_bit(LFL_FORCE_PROMOTE, &lp->flags) &&
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!(lkf & DLM_LKF_NOQUEUE) &&
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cur > DLM_LOCK_NL && req > DLM_LOCK_NL && cur != req)
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lkf |= DLM_LKF_CONVDEADLK;
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}
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if (lp->lvb)
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lkf |= DLM_LKF_VALBLK;
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return lkf;
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}
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/* make_strname - convert GFS lock numbers to a string */
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static inline void make_strname(const struct lm_lockname *lockname,
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struct gdlm_strname *str)
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{
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sprintf(str->name, "%8x%16llx", lockname->ln_type,
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(unsigned long long)lockname->ln_number);
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str->namelen = GDLM_STRNAME_BYTES;
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}
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static int gdlm_create_lp(struct gdlm_ls *ls, struct lm_lockname *name,
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struct gdlm_lock **lpp)
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{
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struct gdlm_lock *lp;
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lp = kzalloc(sizeof(struct gdlm_lock), GFP_KERNEL);
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if (!lp)
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return -ENOMEM;
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lp->lockname = *name;
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make_strname(name, &lp->strname);
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lp->ls = ls;
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lp->cur = DLM_LOCK_IV;
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lp->lvb = NULL;
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lp->hold_null = NULL;
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INIT_LIST_HEAD(&lp->clist);
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INIT_LIST_HEAD(&lp->blist);
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INIT_LIST_HEAD(&lp->delay_list);
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spin_lock(&ls->async_lock);
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list_add(&lp->all_list, &ls->all_locks);
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ls->all_locks_count++;
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spin_unlock(&ls->async_lock);
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*lpp = lp;
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return 0;
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}
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void gdlm_delete_lp(struct gdlm_lock *lp)
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{
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struct gdlm_ls *ls = lp->ls;
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spin_lock(&ls->async_lock);
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if (!list_empty(&lp->clist))
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list_del_init(&lp->clist);
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if (!list_empty(&lp->blist))
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list_del_init(&lp->blist);
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if (!list_empty(&lp->delay_list))
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list_del_init(&lp->delay_list);
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gdlm_assert(!list_empty(&lp->all_list), "%x,%llx", lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number);
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list_del_init(&lp->all_list);
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ls->all_locks_count--;
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spin_unlock(&ls->async_lock);
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kfree(lp);
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}
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int gdlm_get_lock(void *lockspace, struct lm_lockname *name,
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void **lockp)
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{
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struct gdlm_lock *lp;
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int error;
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error = gdlm_create_lp(lockspace, name, &lp);
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*lockp = lp;
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return error;
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}
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void gdlm_put_lock(void *lock)
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{
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gdlm_delete_lp(lock);
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}
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unsigned int gdlm_do_lock(struct gdlm_lock *lp)
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{
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struct gdlm_ls *ls = lp->ls;
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int error, bast = 1;
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/*
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* When recovery is in progress, delay lock requests for submission
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* once recovery is done. Requests for recovery (NOEXP) and unlocks
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* can pass.
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*/
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if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
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!test_bit(LFL_NOBLOCK, &lp->flags) && lp->req != DLM_LOCK_NL) {
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gdlm_queue_delayed(lp);
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return LM_OUT_ASYNC;
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}
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/*
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* Submit the actual lock request.
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*/
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if (test_bit(LFL_NOBAST, &lp->flags))
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bast = 0;
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set_bit(LFL_ACTIVE, &lp->flags);
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log_debug("lk %x,%llx id %x %d,%d %x", lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number, lp->lksb.sb_lkid,
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lp->cur, lp->req, lp->lkf);
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error = dlm_lock(ls->dlm_lockspace, lp->req, &lp->lksb, lp->lkf,
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lp->strname.name, lp->strname.namelen, 0, gdlm_ast,
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lp, bast ? gdlm_bast : NULL);
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if ((error == -EAGAIN) && (lp->lkf & DLM_LKF_NOQUEUE)) {
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lp->lksb.sb_status = -EAGAIN;
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queue_complete(lp);
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error = 0;
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}
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if (error) {
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log_error("%s: gdlm_lock %x,%llx err=%d cur=%d req=%d lkf=%x "
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"flags=%lx", ls->fsname, lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number, error,
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lp->cur, lp->req, lp->lkf, lp->flags);
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return LM_OUT_ERROR;
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}
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return LM_OUT_ASYNC;
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}
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static unsigned int gdlm_do_unlock(struct gdlm_lock *lp)
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{
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struct gdlm_ls *ls = lp->ls;
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unsigned int lkf = 0;
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int error;
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set_bit(LFL_DLM_UNLOCK, &lp->flags);
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set_bit(LFL_ACTIVE, &lp->flags);
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if (lp->lvb)
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lkf = DLM_LKF_VALBLK;
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log_debug("un %x,%llx %x %d %x", lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number,
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lp->lksb.sb_lkid, lp->cur, lkf);
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error = dlm_unlock(ls->dlm_lockspace, lp->lksb.sb_lkid, lkf, NULL, lp);
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if (error) {
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log_error("%s: gdlm_unlock %x,%llx err=%d cur=%d req=%d lkf=%x "
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"flags=%lx", ls->fsname, lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number, error,
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lp->cur, lp->req, lp->lkf, lp->flags);
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return LM_OUT_ERROR;
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}
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return LM_OUT_ASYNC;
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}
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unsigned int gdlm_lock(void *lock, unsigned int cur_state,
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unsigned int req_state, unsigned int flags)
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{
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struct gdlm_lock *lp = lock;
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clear_bit(LFL_DLM_CANCEL, &lp->flags);
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if (flags & LM_FLAG_NOEXP)
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set_bit(LFL_NOBLOCK, &lp->flags);
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check_cur_state(lp, cur_state);
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lp->req = make_mode(req_state);
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lp->lkf = make_flags(lp, flags, lp->cur, lp->req);
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return gdlm_do_lock(lp);
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}
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unsigned int gdlm_unlock(void *lock, unsigned int cur_state)
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{
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struct gdlm_lock *lp = lock;
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clear_bit(LFL_DLM_CANCEL, &lp->flags);
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if (lp->cur == DLM_LOCK_IV)
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return 0;
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return gdlm_do_unlock(lp);
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}
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void gdlm_cancel(void *lock)
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{
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struct gdlm_lock *lp = lock;
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struct gdlm_ls *ls = lp->ls;
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int error, delay_list = 0;
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if (test_bit(LFL_DLM_CANCEL, &lp->flags))
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return;
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log_info("gdlm_cancel %x,%llx flags %lx", lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number, lp->flags);
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spin_lock(&ls->async_lock);
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if (!list_empty(&lp->delay_list)) {
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list_del_init(&lp->delay_list);
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delay_list = 1;
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}
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spin_unlock(&ls->async_lock);
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if (delay_list) {
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set_bit(LFL_CANCEL, &lp->flags);
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set_bit(LFL_ACTIVE, &lp->flags);
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queue_complete(lp);
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return;
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}
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if (!test_bit(LFL_ACTIVE, &lp->flags) ||
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test_bit(LFL_DLM_UNLOCK, &lp->flags)) {
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log_info("gdlm_cancel skip %x,%llx flags %lx",
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lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number, lp->flags);
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return;
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}
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/* the lock is blocked in the dlm */
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set_bit(LFL_DLM_CANCEL, &lp->flags);
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set_bit(LFL_ACTIVE, &lp->flags);
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error = dlm_unlock(ls->dlm_lockspace, lp->lksb.sb_lkid, DLM_LKF_CANCEL,
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NULL, lp);
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log_info("gdlm_cancel rv %d %x,%llx flags %lx", error,
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lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number, lp->flags);
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if (error == -EBUSY)
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clear_bit(LFL_DLM_CANCEL, &lp->flags);
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}
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static int gdlm_add_lvb(struct gdlm_lock *lp)
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{
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char *lvb;
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lvb = kzalloc(GDLM_LVB_SIZE, GFP_KERNEL);
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if (!lvb)
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return -ENOMEM;
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lp->lksb.sb_lvbptr = lvb;
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lp->lvb = lvb;
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return 0;
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}
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static void gdlm_del_lvb(struct gdlm_lock *lp)
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{
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kfree(lp->lvb);
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lp->lvb = NULL;
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lp->lksb.sb_lvbptr = NULL;
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}
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static int gdlm_ast_wait(void *word)
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{
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schedule();
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return 0;
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}
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/* This can do a synchronous dlm request (requiring a lock_dlm thread to get
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the completion) because gfs won't call hold_lvb() during a callback (from
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the context of a lock_dlm thread). */
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static int hold_null_lock(struct gdlm_lock *lp)
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{
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struct gdlm_lock *lpn = NULL;
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int error;
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if (lp->hold_null) {
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printk(KERN_INFO "lock_dlm: lvb already held\n");
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return 0;
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}
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error = gdlm_create_lp(lp->ls, &lp->lockname, &lpn);
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if (error)
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goto out;
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lpn->lksb.sb_lvbptr = junk_lvb;
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lpn->lvb = junk_lvb;
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lpn->req = DLM_LOCK_NL;
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lpn->lkf = DLM_LKF_VALBLK | DLM_LKF_EXPEDITE;
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set_bit(LFL_NOBAST, &lpn->flags);
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set_bit(LFL_INLOCK, &lpn->flags);
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set_bit(LFL_AST_WAIT, &lpn->flags);
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gdlm_do_lock(lpn);
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wait_on_bit(&lpn->flags, LFL_AST_WAIT, gdlm_ast_wait, TASK_UNINTERRUPTIBLE);
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error = lpn->lksb.sb_status;
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if (error) {
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printk(KERN_INFO "lock_dlm: hold_null_lock dlm error %d\n",
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error);
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gdlm_delete_lp(lpn);
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lpn = NULL;
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}
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out:
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lp->hold_null = lpn;
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return error;
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}
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/* This cannot do a synchronous dlm request (requiring a lock_dlm thread to get
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the completion) because gfs may call unhold_lvb() during a callback (from
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the context of a lock_dlm thread) which could cause a deadlock since the
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other lock_dlm thread could be engaged in recovery. */
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static void unhold_null_lock(struct gdlm_lock *lp)
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{
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struct gdlm_lock *lpn = lp->hold_null;
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gdlm_assert(lpn, "%x,%llx", lp->lockname.ln_type,
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(unsigned long long)lp->lockname.ln_number);
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lpn->lksb.sb_lvbptr = NULL;
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lpn->lvb = NULL;
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set_bit(LFL_UNLOCK_DELETE, &lpn->flags);
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gdlm_do_unlock(lpn);
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lp->hold_null = NULL;
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}
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/* Acquire a NL lock because gfs requires the value block to remain
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intact on the resource while the lvb is "held" even if it's holding no locks
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on the resource. */
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int gdlm_hold_lvb(void *lock, char **lvbp)
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{
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struct gdlm_lock *lp = lock;
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int error;
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error = gdlm_add_lvb(lp);
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if (error)
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return error;
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*lvbp = lp->lvb;
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error = hold_null_lock(lp);
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if (error)
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gdlm_del_lvb(lp);
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return error;
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}
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void gdlm_unhold_lvb(void *lock, char *lvb)
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{
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struct gdlm_lock *lp = lock;
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unhold_null_lock(lp);
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gdlm_del_lvb(lp);
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}
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void gdlm_submit_delayed(struct gdlm_ls *ls)
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{
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struct gdlm_lock *lp, *safe;
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spin_lock(&ls->async_lock);
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list_for_each_entry_safe(lp, safe, &ls->delayed, delay_list) {
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list_del_init(&lp->delay_list);
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list_add_tail(&lp->delay_list, &ls->submit);
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}
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spin_unlock(&ls->async_lock);
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wake_up(&ls->thread_wait);
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}
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int gdlm_release_all_locks(struct gdlm_ls *ls)
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{
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struct gdlm_lock *lp, *safe;
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int count = 0;
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|
|
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spin_lock(&ls->async_lock);
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list_for_each_entry_safe(lp, safe, &ls->all_locks, all_list) {
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list_del_init(&lp->all_list);
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if (lp->lvb && lp->lvb != junk_lvb)
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kfree(lp->lvb);
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|
kfree(lp);
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|
count++;
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}
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spin_unlock(&ls->async_lock);
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|
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return count;
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}
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