From 29b7998d887529eca1ef43c8ca7b278448dc983c Mon Sep 17 00:00:00 2001 From: David Teigland Date: Mon, 16 Jan 2006 16:52:38 +0000 Subject: [GFS2] The lock modules for GFS2 This patch contains the pluggable locking modules for GFS2. Signed-off-by: David Teigland Signed-off-by: Steven Whitehouse --- fs/gfs2/locking/dlm/lock.c | 537 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 537 insertions(+) create mode 100644 fs/gfs2/locking/dlm/lock.c (limited to 'fs/gfs2/locking/dlm/lock.c') diff --git a/fs/gfs2/locking/dlm/lock.c b/fs/gfs2/locking/dlm/lock.c new file mode 100644 index 00000000000..daf59d504e2 --- /dev/null +++ b/fs/gfs2/locking/dlm/lock.c @@ -0,0 +1,537 @@ +/****************************************************************************** +******************************************************************************* +** +** 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 "lock_dlm.h" + +static char junk_lvb[GDLM_LVB_SIZE]; + +static void queue_complete(struct gdlm_lock *lp) +{ + struct gdlm_ls *ls = lp->ls; + + clear_bit(LFL_ACTIVE, &lp->flags); + + spin_lock(&ls->async_lock); + list_add_tail(&lp->clist, &ls->complete); + spin_unlock(&ls->async_lock); + wake_up(&ls->thread_wait); +} + +static inline void gdlm_ast(void *astarg) +{ + queue_complete((struct gdlm_lock *) astarg); +} + +static inline void gdlm_bast(void *astarg, int mode) +{ + struct gdlm_lock *lp = astarg; + struct gdlm_ls *ls = lp->ls; + + if (!mode) { + printk("lock_dlm: bast mode zero %x,%"PRIx64"\n", + lp->lockname.ln_type, lp->lockname.ln_number); + return; + } + + spin_lock(&ls->async_lock); + if (!lp->bast_mode) { + list_add_tail(&lp->blist, &ls->blocking); + lp->bast_mode = mode; + } else if (lp->bast_mode < mode) + lp->bast_mode = mode; + spin_unlock(&ls->async_lock); + wake_up(&ls->thread_wait); +} + +void gdlm_queue_delayed(struct gdlm_lock *lp) +{ + struct gdlm_ls *ls = lp->ls; + + spin_lock(&ls->async_lock); + list_add_tail(&lp->delay_list, &ls->delayed); + spin_unlock(&ls->async_lock); +} + +/* convert gfs lock-state to dlm lock-mode */ + +static int16_t make_mode(int16_t lmstate) +{ + switch (lmstate) { + case LM_ST_UNLOCKED: + return DLM_LOCK_NL; + case LM_ST_EXCLUSIVE: + return DLM_LOCK_EX; + case LM_ST_DEFERRED: + return DLM_LOCK_CW; + case LM_ST_SHARED: + return DLM_LOCK_PR; + default: + GDLM_ASSERT(0, printk("unknown LM state %d\n", lmstate);); + } +} + +/* convert dlm lock-mode to gfs lock-state */ + +int16_t gdlm_make_lmstate(int16_t dlmmode) +{ + switch (dlmmode) { + case DLM_LOCK_IV: + case DLM_LOCK_NL: + return LM_ST_UNLOCKED; + case DLM_LOCK_EX: + return LM_ST_EXCLUSIVE; + case DLM_LOCK_CW: + return LM_ST_DEFERRED; + case DLM_LOCK_PR: + return LM_ST_SHARED; + default: + GDLM_ASSERT(0, printk("unknown DLM mode %d\n", dlmmode);); + } +} + +/* verify agreement with GFS on the current lock state, NB: DLM_LOCK_NL and + DLM_LOCK_IV are both considered LM_ST_UNLOCKED by GFS. */ + +static void check_cur_state(struct gdlm_lock *lp, unsigned int cur_state) +{ + int16_t cur = make_mode(cur_state); + if (lp->cur != DLM_LOCK_IV) + GDLM_ASSERT(lp->cur == cur, printk("%d, %d\n", lp->cur, cur);); +} + +static inline unsigned int make_flags(struct gdlm_lock *lp, + unsigned int gfs_flags, + int16_t cur, int16_t req) +{ + unsigned int lkf = 0; + + if (gfs_flags & LM_FLAG_TRY) + lkf |= DLM_LKF_NOQUEUE; + + if (gfs_flags & LM_FLAG_TRY_1CB) { + lkf |= DLM_LKF_NOQUEUE; + lkf |= DLM_LKF_NOQUEUEBAST; + } + + if (gfs_flags & LM_FLAG_PRIORITY) { + lkf |= DLM_LKF_NOORDER; + lkf |= DLM_LKF_HEADQUE; + } + + if (gfs_flags & LM_FLAG_ANY) { + if (req == DLM_LOCK_PR) + lkf |= DLM_LKF_ALTCW; + else if (req == DLM_LOCK_CW) + lkf |= DLM_LKF_ALTPR; + } + + if (lp->lksb.sb_lkid != 0) { + lkf |= DLM_LKF_CONVERT; + + /* Conversion deadlock avoidance by DLM */ + + if (!test_bit(LFL_FORCE_PROMOTE, &lp->flags) && + !(lkf & DLM_LKF_NOQUEUE) && + cur > DLM_LOCK_NL && req > DLM_LOCK_NL && cur != req) + lkf |= DLM_LKF_CONVDEADLK; + } + + if (lp->lvb) + lkf |= DLM_LKF_VALBLK; + + return lkf; +} + +/* make_strname - convert GFS lock numbers to a string */ + +static inline void make_strname(struct lm_lockname *lockname, + struct gdlm_strname *str) +{ + sprintf(str->name, "%8x%16"PRIx64, lockname->ln_type, + lockname->ln_number); + str->namelen = GDLM_STRNAME_BYTES; +} + +int gdlm_create_lp(struct gdlm_ls *ls, struct lm_lockname *name, + struct gdlm_lock **lpp) +{ + struct gdlm_lock *lp; + + lp = kmalloc(sizeof(struct gdlm_lock), GFP_KERNEL); + if (!lp) + return -ENOMEM; + + memset(lp, 0, sizeof(struct gdlm_lock)); + lp->lockname = *name; + lp->ls = ls; + lp->cur = DLM_LOCK_IV; + lp->lvb = NULL; + lp->hold_null = NULL; + init_completion(&lp->ast_wait); + INIT_LIST_HEAD(&lp->clist); + INIT_LIST_HEAD(&lp->blist); + INIT_LIST_HEAD(&lp->delay_list); + + spin_lock(&ls->async_lock); + list_add(&lp->all_list, &ls->all_locks); + ls->all_locks_count++; + spin_unlock(&ls->async_lock); + + *lpp = lp; + return 0; +} + +void gdlm_delete_lp(struct gdlm_lock *lp) +{ + struct gdlm_ls *ls = lp->ls; + + spin_lock(&ls->async_lock); + if (!list_empty(&lp->clist)) + list_del_init(&lp->clist); + if (!list_empty(&lp->blist)) + list_del_init(&lp->blist); + if (!list_empty(&lp->delay_list)) + list_del_init(&lp->delay_list); + GDLM_ASSERT(!list_empty(&lp->all_list),); + list_del_init(&lp->all_list); + ls->all_locks_count--; + spin_unlock(&ls->async_lock); + + kfree(lp); +} + +int gdlm_get_lock(lm_lockspace_t *lockspace, struct lm_lockname *name, + lm_lock_t **lockp) +{ + struct gdlm_lock *lp; + int error; + + error = gdlm_create_lp((struct gdlm_ls *) lockspace, name, &lp); + + *lockp = (lm_lock_t *) lp; + return error; +} + +void gdlm_put_lock(lm_lock_t *lock) +{ + gdlm_delete_lp((struct gdlm_lock *) lock); +} + +void gdlm_do_lock(struct gdlm_lock *lp, struct dlm_range *range) +{ + struct gdlm_ls *ls = lp->ls; + struct gdlm_strname str; + int error, bast = 1; + + /* + * When recovery is in progress, delay lock requests for submission + * once recovery is done. Requests for recovery (NOEXP) and unlocks + * can pass. + */ + + if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) && + !test_bit(LFL_NOBLOCK, &lp->flags) && lp->req != DLM_LOCK_NL) { + gdlm_queue_delayed(lp); + return; + } + + /* + * Submit the actual lock request. + */ + + if (test_bit(LFL_NOBAST, &lp->flags)) + bast = 0; + + make_strname(&lp->lockname, &str); + + set_bit(LFL_ACTIVE, &lp->flags); + + log_debug("lk %x,%"PRIx64" id %x %d,%d %x", lp->lockname.ln_type, + lp->lockname.ln_number, lp->lksb.sb_lkid, + lp->cur, lp->req, lp->lkf); + + error = dlm_lock(ls->dlm_lockspace, lp->req, &lp->lksb, lp->lkf, + str.name, str.namelen, 0, gdlm_ast, (void *) lp, + bast ? gdlm_bast : NULL, range); + + if ((error == -EAGAIN) && (lp->lkf & DLM_LKF_NOQUEUE)) { + lp->lksb.sb_status = -EAGAIN; + queue_complete(lp); + error = 0; + } + + GDLM_ASSERT(!error, + printk("%s: num=%x,%"PRIx64" err=%d cur=%d req=%d lkf=%x\n", + ls->fsname, lp->lockname.ln_type, + lp->lockname.ln_number, error, lp->cur, lp->req, + lp->lkf);); +} + +void gdlm_do_unlock(struct gdlm_lock *lp) +{ + unsigned int lkf = 0; + int error; + + set_bit(LFL_DLM_UNLOCK, &lp->flags); + set_bit(LFL_ACTIVE, &lp->flags); + + if (lp->lvb) + lkf = DLM_LKF_VALBLK; + + log_debug("un %x,%"PRIx64" %x %d %x", lp->lockname.ln_type, + lp->lockname.ln_number, lp->lksb.sb_lkid, lp->cur, lkf); + + error = dlm_unlock(lp->ls->dlm_lockspace, lp->lksb.sb_lkid, lkf, + NULL, lp); + + GDLM_ASSERT(!error, + printk("%s: error=%d num=%x,%"PRIx64" lkf=%x flags=%lx\n", + lp->ls->fsname, error, lp->lockname.ln_type, + lp->lockname.ln_number, lkf, lp->flags);); +} + +unsigned int gdlm_lock(lm_lock_t *lock, unsigned int cur_state, + unsigned int req_state, unsigned int flags) +{ + struct gdlm_lock *lp = (struct gdlm_lock *) lock; + + clear_bit(LFL_DLM_CANCEL, &lp->flags); + if (flags & LM_FLAG_NOEXP) + set_bit(LFL_NOBLOCK, &lp->flags); + + check_cur_state(lp, cur_state); + lp->req = make_mode(req_state); + lp->lkf = make_flags(lp, flags, lp->cur, lp->req); + + gdlm_do_lock(lp, NULL); + return LM_OUT_ASYNC; +} + +unsigned int gdlm_unlock(lm_lock_t *lock, unsigned int cur_state) +{ + struct gdlm_lock *lp = (struct gdlm_lock *) lock; + + clear_bit(LFL_DLM_CANCEL, &lp->flags); + if (lp->cur == DLM_LOCK_IV) + return 0; + gdlm_do_unlock(lp); + return LM_OUT_ASYNC; +} + +void gdlm_cancel(lm_lock_t *lock) +{ + struct gdlm_lock *lp = (struct gdlm_lock *) lock; + struct gdlm_ls *ls = lp->ls; + int error, delay_list = 0; + + if (test_bit(LFL_DLM_CANCEL, &lp->flags)) + return; + + log_all("gdlm_cancel %x,%"PRIx64" flags %lx", + lp->lockname.ln_type, lp->lockname.ln_number, lp->flags); + + spin_lock(&ls->async_lock); + if (!list_empty(&lp->delay_list)) { + list_del_init(&lp->delay_list); + delay_list = 1; + } + spin_unlock(&ls->async_lock); + + if (delay_list) { + set_bit(LFL_CANCEL, &lp->flags); + set_bit(LFL_ACTIVE, &lp->flags); + queue_complete(lp); + return; + } + + if (!test_bit(LFL_ACTIVE, &lp->flags) || + test_bit(LFL_DLM_UNLOCK, &lp->flags)) { + log_all("gdlm_cancel skip %x,%"PRIx64" flags %lx", + lp->lockname.ln_type, lp->lockname.ln_number, + lp->flags); + return; + } + + /* the lock is blocked in the dlm */ + + set_bit(LFL_DLM_CANCEL, &lp->flags); + set_bit(LFL_ACTIVE, &lp->flags); + + error = dlm_unlock(ls->dlm_lockspace, lp->lksb.sb_lkid, DLM_LKF_CANCEL, + NULL, lp); + + log_all("gdlm_cancel rv %d %x,%"PRIx64" flags %lx", error, + lp->lockname.ln_type, lp->lockname.ln_number, lp->flags); + + if (error == -EBUSY) + clear_bit(LFL_DLM_CANCEL, &lp->flags); +} + +int gdlm_add_lvb(struct gdlm_lock *lp) +{ + char *lvb; + + lvb = kmalloc(GDLM_LVB_SIZE, GFP_KERNEL); + if (!lvb) + return -ENOMEM; + + memset(lvb, 0, GDLM_LVB_SIZE); + + lp->lksb.sb_lvbptr = lvb; + lp->lvb = lvb; + return 0; +} + +void gdlm_del_lvb(struct gdlm_lock *lp) +{ + kfree(lp->lvb); + lp->lvb = NULL; + lp->lksb.sb_lvbptr = NULL; +} + +/* This can do a synchronous dlm request (requiring a lock_dlm thread to get + the completion) because gfs won't call hold_lvb() during a callback (from + the context of a lock_dlm thread). */ + +static int hold_null_lock(struct gdlm_lock *lp) +{ + struct gdlm_lock *lpn = NULL; + int error; + + if (lp->hold_null) { + printk("lock_dlm: lvb already held\n"); + return 0; + } + + error = gdlm_create_lp(lp->ls, &lp->lockname, &lpn); + if (error) + goto out; + + lpn->lksb.sb_lvbptr = junk_lvb; + lpn->lvb = junk_lvb; + + lpn->req = DLM_LOCK_NL; + lpn->lkf = DLM_LKF_VALBLK | DLM_LKF_EXPEDITE; + set_bit(LFL_NOBAST, &lpn->flags); + set_bit(LFL_INLOCK, &lpn->flags); + + init_completion(&lpn->ast_wait); + gdlm_do_lock(lpn, NULL); + wait_for_completion(&lpn->ast_wait); + error = lp->lksb.sb_status; + if (error) { + printk("lock_dlm: hold_null_lock dlm error %d\n", error); + gdlm_delete_lp(lpn); + lpn = NULL; + } + out: + lp->hold_null = lpn; + return error; +} + +/* This cannot do a synchronous dlm request (requiring a lock_dlm thread to get + the completion) because gfs may call unhold_lvb() during a callback (from + the context of a lock_dlm thread) which could cause a deadlock since the + other lock_dlm thread could be engaged in recovery. */ + +static void unhold_null_lock(struct gdlm_lock *lp) +{ + struct gdlm_lock *lpn = lp->hold_null; + + GDLM_ASSERT(lpn,); + lpn->lksb.sb_lvbptr = NULL; + lpn->lvb = NULL; + set_bit(LFL_UNLOCK_DELETE, &lpn->flags); + gdlm_do_unlock(lpn); + lp->hold_null = NULL; +} + +/* Acquire a NL lock because gfs requires the value block to remain + intact on the resource while the lvb is "held" even if it's holding no locks + on the resource. */ + +int gdlm_hold_lvb(lm_lock_t *lock, char **lvbp) +{ + struct gdlm_lock *lp = (struct gdlm_lock *) lock; + int error; + + error = gdlm_add_lvb(lp); + if (error) + return error; + + *lvbp = lp->lvb; + + error = hold_null_lock(lp); + if (error) + gdlm_del_lvb(lp); + + return error; +} + +void gdlm_unhold_lvb(lm_lock_t *lock, char *lvb) +{ + struct gdlm_lock *lp = (struct gdlm_lock *) lock; + + unhold_null_lock(lp); + gdlm_del_lvb(lp); +} + +void gdlm_sync_lvb(lm_lock_t *lock, char *lvb) +{ + struct gdlm_lock *lp = (struct gdlm_lock *) lock; + + if (lp->cur != DLM_LOCK_EX) + return; + + init_completion(&lp->ast_wait); + set_bit(LFL_SYNC_LVB, &lp->flags); + + lp->req = DLM_LOCK_EX; + lp->lkf = make_flags(lp, 0, lp->cur, lp->req); + + gdlm_do_lock(lp, NULL); + wait_for_completion(&lp->ast_wait); +} + +void gdlm_submit_delayed(struct gdlm_ls *ls) +{ + struct gdlm_lock *lp, *safe; + + spin_lock(&ls->async_lock); + list_for_each_entry_safe(lp, safe, &ls->delayed, delay_list) { + list_del_init(&lp->delay_list); + list_add_tail(&lp->delay_list, &ls->submit); + } + spin_unlock(&ls->async_lock); + wake_up(&ls->thread_wait); +} + +int gdlm_release_all_locks(struct gdlm_ls *ls) +{ + struct gdlm_lock *lp, *safe; + int count = 0; + + spin_lock(&ls->async_lock); + list_for_each_entry_safe(lp, safe, &ls->all_locks, all_list) { + list_del_init(&lp->all_list); + + if (lp->lvb && lp->lvb != junk_lvb) + kfree(lp->lvb); + kfree(lp); + count++; + } + spin_unlock(&ls->async_lock); + + return count; +} + -- cgit v1.2.3