| // SPDX-License-Identifier: GPL-2.0-only |
| /****************************************************************************** |
| ******************************************************************************* |
| ** |
| ** Copyright (C) 2005-2010 Red Hat, Inc. All rights reserved. |
| ** |
| ** |
| ******************************************************************************* |
| ******************************************************************************/ |
| |
| /* 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 <trace/events/dlm.h> |
| |
| #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 "midcomms.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, |
| const struct dlm_message *ms, bool local); |
| static int receive_extralen(const struct dlm_message *ms); |
| static void do_purge(struct dlm_ls *ls, int nodeid, int pid); |
| static void deactivate_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]; |
| } |
| |
| /* |
| * 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, |
| dlm_iflags_val(lkb), lkb->lkb_status, lkb->lkb_rqmode, |
| lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_wait_nodeid, |
| (unsigned long long)lkb->lkb_recover_seq); |
| } |
| |
| 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); |
| } |
| |
| 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); |
| } |
| |
| /* Threads cannot use the lockspace while it's being recovered */ |
| |
| void dlm_lock_recovery(struct dlm_ls *ls) |
| { |
| down_read(&ls->ls_in_recovery); |
| } |
| |
| void dlm_unlock_recovery(struct dlm_ls *ls) |
| { |
| up_read(&ls->ls_in_recovery); |
| } |
| |
| int dlm_lock_recovery_try(struct dlm_ls *ls) |
| { |
| return down_read_trylock(&ls->ls_in_recovery); |
| } |
| |
| static inline int can_be_queued(struct dlm_lkb *lkb) |
| { |
| return !(lkb->lkb_exflags & DLM_LKF_NOQUEUE); |
| } |
| |
| static inline int force_blocking_asts(struct dlm_lkb *lkb) |
| { |
| return (lkb->lkb_exflags & DLM_LKF_NOQUEUEBAST); |
| } |
| |
| static inline int is_demoted(struct dlm_lkb *lkb) |
| { |
| return test_bit(DLM_SBF_DEMOTED_BIT, &lkb->lkb_sbflags); |
| } |
| |
| static inline int is_altmode(struct dlm_lkb *lkb) |
| { |
| return test_bit(DLM_SBF_ALTMODE_BIT, &lkb->lkb_sbflags); |
| } |
| |
| static inline int is_granted(struct dlm_lkb *lkb) |
| { |
| return (lkb->lkb_status == DLM_LKSTS_GRANTED); |
| } |
| |
| static inline int is_remote(struct dlm_rsb *r) |
| { |
| DLM_ASSERT(r->res_nodeid >= 0, dlm_print_rsb(r);); |
| return !!r->res_nodeid; |
| } |
| |
| static inline int is_process_copy(struct dlm_lkb *lkb) |
| { |
| return lkb->lkb_nodeid && |
| !test_bit(DLM_IFL_MSTCPY_BIT, &lkb->lkb_iflags); |
| } |
| |
| static inline int is_master_copy(struct dlm_lkb *lkb) |
| { |
| return test_bit(DLM_IFL_MSTCPY_BIT, &lkb->lkb_iflags); |
| } |
| |
| 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; |
| } |
| |
| static inline int down_conversion(struct dlm_lkb *lkb) |
| { |
| return (!middle_conversion(lkb) && lkb->lkb_rqmode < lkb->lkb_grmode); |
| } |
| |
| static inline int is_overlap_unlock(struct dlm_lkb *lkb) |
| { |
| return test_bit(DLM_IFL_OVERLAP_UNLOCK_BIT, &lkb->lkb_iflags); |
| } |
| |
| static inline int is_overlap_cancel(struct dlm_lkb *lkb) |
| { |
| return test_bit(DLM_IFL_OVERLAP_CANCEL_BIT, &lkb->lkb_iflags); |
| } |
| |
| static inline int is_overlap(struct dlm_lkb *lkb) |
| { |
| return test_bit(DLM_IFL_OVERLAP_UNLOCK_BIT, &lkb->lkb_iflags) || |
| test_bit(DLM_IFL_OVERLAP_CANCEL_BIT, &lkb->lkb_iflags); |
| } |
| |
| static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv) |
| { |
| if (is_master_copy(lkb)) |
| return; |
| |
| DLM_ASSERT(lkb->lkb_lksb, dlm_print_lkb(lkb);); |
| |
| if (rv == -DLM_ECANCEL && |
| test_and_clear_bit(DLM_IFL_DEADLOCK_CANCEL_BIT, &lkb->lkb_iflags)) |
| rv = -EDEADLK; |
| |
| dlm_add_cb(lkb, DLM_CB_CAST, lkb->lkb_grmode, rv, dlm_sbflags_val(lkb)); |
| } |
| |
| 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); |
| } |
| |
| 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); |
| } |
| } |
| |
| /* |
| * Basic operations on rsb's and lkb's |
| */ |
| |
| static inline unsigned long rsb_toss_jiffies(void) |
| { |
| return jiffies + (READ_ONCE(dlm_config.ci_toss_secs) * HZ); |
| } |
| |
| /* 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) |
| { |
| /* inactive rsbs are not ref counted */ |
| WARN_ON(rsb_flag(r, RSB_INACTIVE)); |
| kref_get(&r->res_ref); |
| } |
| |
| void dlm_hold_rsb(struct dlm_rsb *r) |
| { |
| hold_rsb(r); |
| } |
| |
| /* TODO move this to lib/refcount.c */ |
| static __must_check bool |
| dlm_refcount_dec_and_write_lock_bh(refcount_t *r, rwlock_t *lock) |
| __cond_acquires(lock) |
| { |
| if (refcount_dec_not_one(r)) |
| return false; |
| |
| write_lock_bh(lock); |
| if (!refcount_dec_and_test(r)) { |
| write_unlock_bh(lock); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /* TODO move this to include/linux/kref.h */ |
| static inline int dlm_kref_put_write_lock_bh(struct kref *kref, |
| void (*release)(struct kref *kref), |
| rwlock_t *lock) |
| { |
| if (dlm_refcount_dec_and_write_lock_bh(&kref->refcount, lock)) { |
| release(kref); |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static void put_rsb(struct dlm_rsb *r) |
| { |
| struct dlm_ls *ls = r->res_ls; |
| int rv; |
| |
| rv = dlm_kref_put_write_lock_bh(&r->res_ref, deactivate_rsb, |
| &ls->ls_rsbtbl_lock); |
| if (rv) |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| } |
| |
| void dlm_put_rsb(struct dlm_rsb *r) |
| { |
| put_rsb(r); |
| } |
| |
| /* connected with timer_delete_sync() in dlm_ls_stop() to stop |
| * new timers when recovery is triggered and don't run them |
| * again until a resume_scan_timer() tries it again. |
| */ |
| static void enable_scan_timer(struct dlm_ls *ls, unsigned long jiffies) |
| { |
| if (!dlm_locking_stopped(ls)) |
| mod_timer(&ls->ls_scan_timer, jiffies); |
| } |
| |
| /* This function tries to resume the timer callback if a rsb |
| * is on the scan list and no timer is pending. It might that |
| * the first entry is on currently executed as timer callback |
| * but we don't care if a timer queued up again and does |
| * nothing. Should be a rare case. |
| */ |
| void resume_scan_timer(struct dlm_ls *ls) |
| { |
| struct dlm_rsb *r; |
| |
| spin_lock_bh(&ls->ls_scan_lock); |
| r = list_first_entry_or_null(&ls->ls_scan_list, struct dlm_rsb, |
| res_scan_list); |
| if (r && !timer_pending(&ls->ls_scan_timer)) |
| enable_scan_timer(ls, r->res_toss_time); |
| spin_unlock_bh(&ls->ls_scan_lock); |
| } |
| |
| /* ls_rsbtbl_lock must be held */ |
| |
| static void del_scan(struct dlm_ls *ls, struct dlm_rsb *r) |
| { |
| struct dlm_rsb *first; |
| |
| /* active rsbs should never be on the scan list */ |
| WARN_ON(!rsb_flag(r, RSB_INACTIVE)); |
| |
| spin_lock_bh(&ls->ls_scan_lock); |
| r->res_toss_time = 0; |
| |
| /* if the rsb is not queued do nothing */ |
| if (list_empty(&r->res_scan_list)) |
| goto out; |
| |
| /* get the first element before delete */ |
| first = list_first_entry(&ls->ls_scan_list, struct dlm_rsb, |
| res_scan_list); |
| list_del_init(&r->res_scan_list); |
| /* check if the first element was the rsb we deleted */ |
| if (first == r) { |
| /* try to get the new first element, if the list |
| * is empty now try to delete the timer, if we are |
| * too late we don't care. |
| * |
| * if the list isn't empty and a new first element got |
| * in place, set the new timer expire time. |
| */ |
| first = list_first_entry_or_null(&ls->ls_scan_list, struct dlm_rsb, |
| res_scan_list); |
| if (!first) |
| timer_delete(&ls->ls_scan_timer); |
| else |
| enable_scan_timer(ls, first->res_toss_time); |
| } |
| |
| out: |
| spin_unlock_bh(&ls->ls_scan_lock); |
| } |
| |
| static void add_scan(struct dlm_ls *ls, struct dlm_rsb *r) |
| { |
| int our_nodeid = dlm_our_nodeid(); |
| struct dlm_rsb *first; |
| |
| /* A dir record for a remote master rsb should never be on the scan list. */ |
| WARN_ON(!dlm_no_directory(ls) && |
| (r->res_master_nodeid != our_nodeid) && |
| (dlm_dir_nodeid(r) == our_nodeid)); |
| |
| /* An active rsb should never be on the scan list. */ |
| WARN_ON(!rsb_flag(r, RSB_INACTIVE)); |
| |
| /* An rsb should not already be on the scan list. */ |
| WARN_ON(!list_empty(&r->res_scan_list)); |
| |
| spin_lock_bh(&ls->ls_scan_lock); |
| /* set the new rsb absolute expire time in the rsb */ |
| r->res_toss_time = rsb_toss_jiffies(); |
| if (list_empty(&ls->ls_scan_list)) { |
| /* if the queue is empty add the element and it's |
| * our new expire time |
| */ |
| list_add_tail(&r->res_scan_list, &ls->ls_scan_list); |
| enable_scan_timer(ls, r->res_toss_time); |
| } else { |
| /* try to get the maybe new first element and then add |
| * to this rsb with the oldest expire time to the end |
| * of the queue. If the list was empty before this |
| * rsb expire time is our next expiration if it wasn't |
| * the now new first elemet is our new expiration time |
| */ |
| first = list_first_entry_or_null(&ls->ls_scan_list, struct dlm_rsb, |
| res_scan_list); |
| list_add_tail(&r->res_scan_list, &ls->ls_scan_list); |
| if (!first) |
| enable_scan_timer(ls, r->res_toss_time); |
| else |
| enable_scan_timer(ls, first->res_toss_time); |
| } |
| spin_unlock_bh(&ls->ls_scan_lock); |
| } |
| |
| /* if we hit contention we do in 250 ms a retry to trylock. |
| * if there is any other mod_timer in between we don't care |
| * about that it expires earlier again this is only for the |
| * unlikely case nothing happened in this time. |
| */ |
| #define DLM_TOSS_TIMER_RETRY (jiffies + msecs_to_jiffies(250)) |
| |
| /* Called by lockspace scan_timer to free unused rsb's. */ |
| |
| void dlm_rsb_scan(struct timer_list *timer) |
| { |
| struct dlm_ls *ls = from_timer(ls, timer, ls_scan_timer); |
| int our_nodeid = dlm_our_nodeid(); |
| struct dlm_rsb *r; |
| int rv; |
| |
| while (1) { |
| /* interrupting point to leave iteration when |
| * recovery waits for timer_delete_sync(), recovery |
| * will take care to delete everything in scan list. |
| */ |
| if (dlm_locking_stopped(ls)) |
| break; |
| |
| rv = spin_trylock(&ls->ls_scan_lock); |
| if (!rv) { |
| /* rearm again try timer */ |
| enable_scan_timer(ls, DLM_TOSS_TIMER_RETRY); |
| break; |
| } |
| |
| r = list_first_entry_or_null(&ls->ls_scan_list, struct dlm_rsb, |
| res_scan_list); |
| if (!r) { |
| /* the next add_scan will enable the timer again */ |
| spin_unlock(&ls->ls_scan_lock); |
| break; |
| } |
| |
| /* |
| * If the first rsb is not yet expired, then stop because the |
| * list is sorted with nearest expiration first. |
| */ |
| if (time_before(jiffies, r->res_toss_time)) { |
| /* rearm with the next rsb to expire in the future */ |
| enable_scan_timer(ls, r->res_toss_time); |
| spin_unlock(&ls->ls_scan_lock); |
| break; |
| } |
| |
| /* in find_rsb_dir/nodir there is a reverse order of this |
| * lock, however this is only a trylock if we hit some |
| * possible contention we try it again. |
| */ |
| rv = write_trylock(&ls->ls_rsbtbl_lock); |
| if (!rv) { |
| spin_unlock(&ls->ls_scan_lock); |
| /* rearm again try timer */ |
| enable_scan_timer(ls, DLM_TOSS_TIMER_RETRY); |
| break; |
| } |
| |
| list_del(&r->res_slow_list); |
| rhashtable_remove_fast(&ls->ls_rsbtbl, &r->res_node, |
| dlm_rhash_rsb_params); |
| rsb_clear_flag(r, RSB_HASHED); |
| |
| /* ls_rsbtbl_lock is not needed when calling send_remove() */ |
| write_unlock(&ls->ls_rsbtbl_lock); |
| |
| list_del_init(&r->res_scan_list); |
| spin_unlock(&ls->ls_scan_lock); |
| |
| /* An rsb that is a dir record for a remote master rsb |
| * cannot be removed, and should not have a timer enabled. |
| */ |
| WARN_ON(!dlm_no_directory(ls) && |
| (r->res_master_nodeid != our_nodeid) && |
| (dlm_dir_nodeid(r) == our_nodeid)); |
| |
| /* We're the master of this rsb but we're not |
| * the directory record, so we need to tell the |
| * dir node to remove the dir record |
| */ |
| if (!dlm_no_directory(ls) && |
| (r->res_master_nodeid == our_nodeid) && |
| (dlm_dir_nodeid(r) != our_nodeid)) |
| send_remove(r); |
| |
| free_inactive_rsb(r); |
| } |
| } |
| |
| /* 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, const void *name, int len, |
| struct dlm_rsb **r_ret) |
| { |
| struct dlm_rsb *r; |
| |
| r = dlm_allocate_rsb(ls); |
| if (!r) |
| return -ENOMEM; |
| |
| r->res_ls = ls; |
| r->res_length = len; |
| memcpy(r->res_name, name, len); |
| spin_lock_init(&r->res_lock); |
| |
| 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_scan_list); |
| INIT_LIST_HEAD(&r->res_recover_list); |
| INIT_LIST_HEAD(&r->res_masters_list); |
| |
| *r_ret = r; |
| return 0; |
| } |
| |
| int dlm_search_rsb_tree(struct rhashtable *rhash, const void *name, int len, |
| struct dlm_rsb **r_ret) |
| { |
| char key[DLM_RESNAME_MAXLEN] = {}; |
| |
| memcpy(key, name, len); |
| *r_ret = rhashtable_lookup_fast(rhash, &key, dlm_rhash_rsb_params); |
| if (*r_ret) |
| return 0; |
| |
| return -EBADR; |
| } |
| |
| static int rsb_insert(struct dlm_rsb *rsb, struct rhashtable *rhash) |
| { |
| int rv; |
| |
| rv = rhashtable_insert_fast(rhash, &rsb->res_node, |
| dlm_rhash_rsb_params); |
| if (!rv) |
| rsb_set_flag(rsb, RSB_HASHED); |
| |
| return rv; |
| } |
| |
| /* |
| * 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. |
| * |
| * deactivate_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, const void *name, int len, |
| uint32_t hash, 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. |
| * (They sent a request instead of lookup because they are using |
| * an rsb taken from their scan list.) |
| */ |
| |
| if (from_local || from_dir || |
| (from_other && (dir_nodeid == our_nodeid))) { |
| create = 1; |
| } |
| |
| retry: |
| |
| /* check if the rsb is active under read lock - likely path */ |
| read_lock_bh(&ls->ls_rsbtbl_lock); |
| error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r); |
| if (error) { |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto do_new; |
| } |
| |
| /* |
| * rsb is active, so we can't check master_nodeid without lock_rsb. |
| */ |
| |
| if (rsb_flag(r, RSB_INACTIVE)) { |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto do_inactive; |
| } |
| |
| kref_get(&r->res_ref); |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto out; |
| |
| |
| do_inactive: |
| write_lock_bh(&ls->ls_rsbtbl_lock); |
| |
| /* |
| * The expectation here is that the rsb will have HASHED and |
| * INACTIVE flags set, and that the rsb can be moved from |
| * inactive back to active again. However, between releasing |
| * the read lock and acquiring the write lock, this rsb could |
| * have been removed from rsbtbl, and had HASHED cleared, to |
| * be freed. To deal with this case, we would normally need |
| * to repeat dlm_search_rsb_tree while holding the write lock, |
| * but rcu allows us to simply check the HASHED flag, because |
| * the rcu read lock means the rsb will not be freed yet. |
| * If the HASHED flag is not set, then the rsb is being freed, |
| * so we add a new rsb struct. If the HASHED flag is set, |
| * and INACTIVE is not set, it means another thread has |
| * made the rsb active, as we're expecting to do here, and |
| * we just repeat the lookup (this will be very unlikely.) |
| */ |
| if (rsb_flag(r, RSB_HASHED)) { |
| if (!rsb_flag(r, RSB_INACTIVE)) { |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto retry; |
| } |
| } else { |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| 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 inactive, 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 inactive from_other %d master %d dir %d %s", |
| from_nodeid, r->res_master_nodeid, dir_nodeid, |
| r->res_name); |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| error = -ENOTBLK; |
| goto out; |
| } |
| |
| if ((r->res_master_nodeid != our_nodeid) && from_dir) { |
| /* don't think this should ever happen */ |
| log_error(ls, "find_rsb inactive 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; |
| } |
| |
| /* A dir record will not be on the scan list. */ |
| if (r->res_dir_nodeid != our_nodeid) |
| del_scan(ls, r); |
| list_move(&r->res_slow_list, &ls->ls_slow_active); |
| rsb_clear_flag(r, RSB_INACTIVE); |
| kref_init(&r->res_ref); /* ref is now used in active state */ |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| |
| goto out; |
| |
| |
| do_new: |
| /* |
| * rsb not found |
| */ |
| |
| if (error == -EBADR && !create) |
| goto out; |
| |
| error = get_rsb_struct(ls, name, len, &r); |
| if (WARN_ON_ONCE(error)) |
| goto out; |
| |
| r->res_hash = hash; |
| r->res_dir_nodeid = dir_nodeid; |
| kref_init(&r->res_ref); |
| |
| if (from_dir) { |
| /* want to see how often this happens */ |
| log_debug(ls, "find_rsb new from_dir %d recreate %s", |
| from_nodeid, r->res_name); |
| r->res_master_nodeid = our_nodeid; |
| r->res_nodeid = 0; |
| goto out_add; |
| } |
| |
| if (from_other && (dir_nodeid != our_nodeid)) { |
| /* should never happen */ |
| log_error(ls, "find_rsb new from_other %d dir %d our %d %s", |
| from_nodeid, dir_nodeid, our_nodeid, r->res_name); |
| dlm_free_rsb(r); |
| r = NULL; |
| error = -ENOTBLK; |
| goto out; |
| } |
| |
| if (from_other) { |
| log_debug(ls, "find_rsb new from_other %d dir %d %s", |
| from_nodeid, dir_nodeid, r->res_name); |
| } |
| |
| if (dir_nodeid == our_nodeid) { |
| /* When we are the dir nodeid, we can set the master |
| node immediately */ |
| r->res_master_nodeid = our_nodeid; |
| r->res_nodeid = 0; |
| } else { |
| /* set_master will send_lookup to dir_nodeid */ |
| r->res_master_nodeid = 0; |
| r->res_nodeid = -1; |
| } |
| |
| out_add: |
| |
| write_lock_bh(&ls->ls_rsbtbl_lock); |
| error = rsb_insert(r, &ls->ls_rsbtbl); |
| if (error == -EEXIST) { |
| /* somebody else was faster and it seems the |
| * rsb exists now, we do a whole relookup |
| */ |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| dlm_free_rsb(r); |
| goto retry; |
| } else if (!error) { |
| list_add(&r->res_slow_list, &ls->ls_slow_active); |
| } |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| out: |
| *r_ret = r; |
| return error; |
| } |
| |
| /* During recovery, other nodes can send us new MSTCPY locks (from |
| dlm_recover_locks) before we've made ourself master (in |
| dlm_recover_masters). */ |
| |
| static int find_rsb_nodir(struct dlm_ls *ls, const void *name, int len, |
| uint32_t hash, 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 recover = (flags & R_RECEIVE_RECOVER); |
| int error; |
| |
| retry: |
| |
| /* check if the rsb is in active state under read lock - likely path */ |
| read_lock_bh(&ls->ls_rsbtbl_lock); |
| error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r); |
| if (error) { |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto do_new; |
| } |
| |
| if (rsb_flag(r, RSB_INACTIVE)) { |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto do_inactive; |
| } |
| |
| /* |
| * rsb is active, so we can't check master_nodeid without lock_rsb. |
| */ |
| |
| kref_get(&r->res_ref); |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| |
| goto out; |
| |
| |
| do_inactive: |
| write_lock_bh(&ls->ls_rsbtbl_lock); |
| |
| /* See comment in find_rsb_dir. */ |
| if (rsb_flag(r, RSB_HASHED)) { |
| if (!rsb_flag(r, RSB_INACTIVE)) { |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto retry; |
| } |
| } else { |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto do_new; |
| } |
| |
| |
| /* |
| * rsb found inactive. No other thread is using this rsb because |
| * it's inactive, so we can look at or update res_master_nodeid |
| * without lock_rsb. |
| */ |
| |
| if (!recover && (r->res_master_nodeid != our_nodeid) && from_nodeid) { |
| /* our rsb is not master, and another node has sent us a |
| request; this should never happen */ |
| log_error(ls, "find_rsb inactive from_nodeid %d master %d dir %d", |
| from_nodeid, r->res_master_nodeid, dir_nodeid); |
| dlm_print_rsb(r); |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| error = -ENOTBLK; |
| goto out; |
| } |
| |
| if (!recover && (r->res_master_nodeid != our_nodeid) && |
| (dir_nodeid == our_nodeid)) { |
| /* our rsb is not master, and we are dir; may as well fix it; |
| this should never happen */ |
| log_error(ls, "find_rsb inactive our %d master %d dir %d", |
| our_nodeid, r->res_master_nodeid, dir_nodeid); |
| dlm_print_rsb(r); |
| r->res_master_nodeid = our_nodeid; |
| r->res_nodeid = 0; |
| } |
| |
| list_move(&r->res_slow_list, &ls->ls_slow_active); |
| rsb_clear_flag(r, RSB_INACTIVE); |
| kref_init(&r->res_ref); |
| del_scan(ls, r); |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| |
| goto out; |
| |
| |
| do_new: |
| /* |
| * rsb not found |
| */ |
| |
| error = get_rsb_struct(ls, name, len, &r); |
| if (WARN_ON_ONCE(error)) |
| goto out; |
| |
| r->res_hash = hash; |
| r->res_dir_nodeid = dir_nodeid; |
| r->res_master_nodeid = dir_nodeid; |
| r->res_nodeid = (dir_nodeid == our_nodeid) ? 0 : dir_nodeid; |
| kref_init(&r->res_ref); |
| |
| write_lock_bh(&ls->ls_rsbtbl_lock); |
| error = rsb_insert(r, &ls->ls_rsbtbl); |
| if (error == -EEXIST) { |
| /* somebody else was faster and it seems the |
| * rsb exists now, we do a whole relookup |
| */ |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| dlm_free_rsb(r); |
| goto retry; |
| } else if (!error) { |
| list_add(&r->res_slow_list, &ls->ls_slow_active); |
| } |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| |
| out: |
| *r_ret = r; |
| return error; |
| } |
| |
| /* |
| * rsb rcu usage |
| * |
| * While rcu read lock is held, the rsb cannot be freed, |
| * which allows a lookup optimization. |
| * |
| * Two threads are accessing the same rsb concurrently, |
| * the first (A) is trying to use the rsb, the second (B) |
| * is trying to free the rsb. |
| * |
| * thread A thread B |
| * (trying to use rsb) (trying to free rsb) |
| * |
| * A1. rcu read lock |
| * A2. rsbtbl read lock |
| * A3. look up rsb in rsbtbl |
| * A4. rsbtbl read unlock |
| * B1. rsbtbl write lock |
| * B2. look up rsb in rsbtbl |
| * B3. remove rsb from rsbtbl |
| * B4. clear rsb HASHED flag |
| * B5. rsbtbl write unlock |
| * B6. begin freeing rsb using rcu... |
| * |
| * (rsb is inactive, so try to make it active again) |
| * A5. read rsb HASHED flag (safe because rsb is not freed yet) |
| * A6. the rsb HASHED flag is not set, which it means the rsb |
| * is being removed from rsbtbl and freed, so don't use it. |
| * A7. rcu read unlock |
| * |
| * B7. ...finish freeing rsb using rcu |
| * A8. create a new rsb |
| * |
| * Without the rcu optimization, steps A5-8 would need to do |
| * an extra rsbtbl lookup: |
| * A5. rsbtbl write lock |
| * A6. look up rsb in rsbtbl, not found |
| * A7. rsbtbl write unlock |
| * A8. create a new rsb |
| */ |
| |
| static int find_rsb(struct dlm_ls *ls, const void *name, int len, |
| int from_nodeid, unsigned int flags, |
| struct dlm_rsb **r_ret) |
| { |
| int dir_nodeid; |
| uint32_t hash; |
| int rv; |
| |
| if (len > DLM_RESNAME_MAXLEN) |
| return -EINVAL; |
| |
| hash = jhash(name, len, 0); |
| dir_nodeid = dlm_hash2nodeid(ls, hash); |
| |
| rcu_read_lock(); |
| if (dlm_no_directory(ls)) |
| rv = find_rsb_nodir(ls, name, len, hash, dir_nodeid, |
| from_nodeid, flags, r_ret); |
| else |
| rv = find_rsb_dir(ls, name, len, hash, dir_nodeid, |
| from_nodeid, flags, r_ret); |
| rcu_read_unlock(); |
| return rv; |
| } |
| |
| /* we have received a request and found that res_master_nodeid != our_nodeid, |
| so we need to return an error or make ourself the master */ |
| |
| static int validate_master_nodeid(struct dlm_ls *ls, struct dlm_rsb *r, |
| int from_nodeid) |
| { |
| if (dlm_no_directory(ls)) { |
| log_error(ls, "find_rsb keep from_nodeid %d master %d dir %d", |
| from_nodeid, r->res_master_nodeid, |
| r->res_dir_nodeid); |
| dlm_print_rsb(r); |
| return -ENOTBLK; |
| } |
| |
| if (from_nodeid != r->res_dir_nodeid) { |
| /* our rsb is not master, and another node (not the dir node) |
| has sent us a request. this is much more common when our |
| master_nodeid is zero, so limit debug to non-zero. */ |
| |
| if (r->res_master_nodeid) { |
| log_debug(ls, "validate master from_other %d master %d " |
| "dir %d first %x %s", from_nodeid, |
| r->res_master_nodeid, r->res_dir_nodeid, |
| r->res_first_lkid, r->res_name); |
| } |
| return -ENOTBLK; |
| } else { |
| /* our rsb is not master, but the dir nodeid has sent us a |
| request; this could happen with master 0 / res_nodeid -1 */ |
| |
| if (r->res_master_nodeid) { |
| log_error(ls, "validate master from_dir %d master %d " |
| "first %x %s", |
| from_nodeid, r->res_master_nodeid, |
| r->res_first_lkid, r->res_name); |
| } |
| |
| r->res_master_nodeid = dlm_our_nodeid(); |
| r->res_nodeid = 0; |
| return 0; |
| } |
| } |
| |
| static void __dlm_master_lookup(struct dlm_ls *ls, struct dlm_rsb *r, int our_nodeid, |
| int from_nodeid, bool is_inactive, unsigned int flags, |
| int *r_nodeid, int *result) |
| { |
| int fix_master = (flags & DLM_LU_RECOVER_MASTER); |
| int from_master = (flags & DLM_LU_RECOVER_DIR); |
| |
| if (r->res_dir_nodeid != our_nodeid) { |
| /* should not happen, but may as well fix it and carry on */ |
| log_error(ls, "%s res_dir %d our %d %s", __func__, |
| r->res_dir_nodeid, our_nodeid, r->res_name); |
| r->res_dir_nodeid = our_nodeid; |
| } |
| |
| if (fix_master && dlm_is_removed(ls, r->res_master_nodeid)) { |
| /* Recovery uses this function to set a new master when |
| * the previous master failed. Setting NEW_MASTER will |
| * force dlm_recover_masters to call recover_master on this |
| * rsb even though the res_nodeid is no longer removed. |
| */ |
| |
| r->res_master_nodeid = from_nodeid; |
| r->res_nodeid = from_nodeid; |
| rsb_set_flag(r, RSB_NEW_MASTER); |
| |
| if (is_inactive) { |
| /* I don't think we should ever find it inactive. */ |
| log_error(ls, "%s fix_master inactive", __func__); |
| dlm_dump_rsb(r); |
| } |
| } |
| |
| if (from_master && (r->res_master_nodeid != from_nodeid)) { |
| /* this will happen if from_nodeid became master during |
| * a previous recovery cycle, and we aborted the previous |
| * cycle before recovering this master value |
| */ |
| |
| log_limit(ls, "%s from_master %d master_nodeid %d res_nodeid %d first %x %s", |
| __func__, from_nodeid, r->res_master_nodeid, |
| r->res_nodeid, r->res_first_lkid, r->res_name); |
| |
| if (r->res_master_nodeid == our_nodeid) { |
| log_error(ls, "from_master %d our_master", from_nodeid); |
| dlm_dump_rsb(r); |
| goto ret_assign; |
| } |
| |
| r->res_master_nodeid = from_nodeid; |
| r->res_nodeid = from_nodeid; |
| rsb_set_flag(r, RSB_NEW_MASTER); |
| } |
| |
| if (!r->res_master_nodeid) { |
| /* this will happen if recovery happens while we're looking |
| * up the master for this rsb |
| */ |
| |
| log_debug(ls, "%s master 0 to %d first %x %s", __func__, |
| from_nodeid, r->res_first_lkid, r->res_name); |
| r->res_master_nodeid = from_nodeid; |
| r->res_nodeid = from_nodeid; |
| } |
| |
| if (!from_master && !fix_master && |
| (r->res_master_nodeid == from_nodeid)) { |
| /* this can happen when the master sends remove, the dir node |
| * finds the rsb on the active list and ignores the remove, |
| * and the former master sends a lookup |
| */ |
| |
| log_limit(ls, "%s from master %d flags %x first %x %s", |
| __func__, from_nodeid, flags, r->res_first_lkid, |
| r->res_name); |
| } |
| |
| ret_assign: |
| *r_nodeid = r->res_master_nodeid; |
| if (result) |
| *result = DLM_LU_MATCH; |
| } |
| |
| /* |
| * We're the dir node for this res and another node wants to know the |
| * master nodeid. During normal operation (non recovery) this is only |
| * called from receive_lookup(); master lookups when the local node is |
| * the dir node are done by find_rsb(). |
| * |
| * normal operation, we are the dir node for a resource |
| * . _request_lock |
| * . set_master |
| * . send_lookup |
| * . receive_lookup |
| * . dlm_master_lookup flags 0 |
| * |
| * recover directory, we are rebuilding dir for all resources |
| * . dlm_recover_directory |
| * . dlm_rcom_names |
| * remote node sends back the rsb names it is master of and we are dir of |
| * . dlm_master_lookup RECOVER_DIR (fix_master 0, from_master 1) |
| * we either create new rsb setting remote node as master, or find existing |
| * rsb and set master to be the remote node. |
| * |
| * recover masters, we are finding the new master for resources |
| * . dlm_recover_masters |
| * . recover_master |
| * . dlm_send_rcom_lookup |
| * . receive_rcom_lookup |
| * . dlm_master_lookup RECOVER_MASTER (fix_master 1, from_master 0) |
| */ |
| |
| static int _dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *name, |
| int len, unsigned int flags, int *r_nodeid, int *result) |
| { |
| struct dlm_rsb *r = NULL; |
| uint32_t hash; |
| int our_nodeid = dlm_our_nodeid(); |
| int dir_nodeid, error; |
| |
| if (len > DLM_RESNAME_MAXLEN) |
| return -EINVAL; |
| |
| if (from_nodeid == our_nodeid) { |
| log_error(ls, "dlm_master_lookup from our_nodeid %d flags %x", |
| our_nodeid, flags); |
| return -EINVAL; |
| } |
| |
| hash = jhash(name, len, 0); |
| dir_nodeid = dlm_hash2nodeid(ls, hash); |
| if (dir_nodeid != our_nodeid) { |
| log_error(ls, "dlm_master_lookup from %d dir %d our %d h %x %d", |
| from_nodeid, dir_nodeid, our_nodeid, hash, |
| ls->ls_num_nodes); |
| *r_nodeid = -1; |
| return -EINVAL; |
| } |
| |
| retry: |
| |
| /* check if the rsb is active under read lock - likely path */ |
| read_lock_bh(&ls->ls_rsbtbl_lock); |
| error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r); |
| if (!error) { |
| if (rsb_flag(r, RSB_INACTIVE)) { |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto do_inactive; |
| } |
| |
| /* because the rsb is active, we need to lock_rsb before |
| * checking/changing re_master_nodeid |
| */ |
| |
| hold_rsb(r); |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| lock_rsb(r); |
| |
| __dlm_master_lookup(ls, r, our_nodeid, from_nodeid, false, |
| flags, r_nodeid, result); |
| |
| /* the rsb was active */ |
| unlock_rsb(r); |
| put_rsb(r); |
| |
| return 0; |
| } else { |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto not_found; |
| } |
| |
| do_inactive: |
| /* unlikely path - relookup under write */ |
| write_lock_bh(&ls->ls_rsbtbl_lock); |
| |
| error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r); |
| if (!error) { |
| if (!rsb_flag(r, RSB_INACTIVE)) { |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| /* something as changed, very unlikely but |
| * try again |
| */ |
| goto retry; |
| } |
| } else { |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| goto not_found; |
| } |
| |
| /* because the rsb is inactive, it's not refcounted and lock_rsb |
| is not used, but is protected by the rsbtbl lock */ |
| |
| __dlm_master_lookup(ls, r, our_nodeid, from_nodeid, true, flags, |
| r_nodeid, result); |
| |
| /* A dir record rsb should never be on scan list. */ |
| /* Try to fix this with del_scan? */ |
| WARN_ON(!list_empty(&r->res_scan_list)); |
| |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| |
| return 0; |
| |
| not_found: |
| error = get_rsb_struct(ls, name, len, &r); |
| if (WARN_ON_ONCE(error)) |
| goto out; |
| |
| r->res_hash = hash; |
| r->res_dir_nodeid = our_nodeid; |
| r->res_master_nodeid = from_nodeid; |
| r->res_nodeid = from_nodeid; |
| rsb_set_flag(r, RSB_INACTIVE); |
| |
| write_lock_bh(&ls->ls_rsbtbl_lock); |
| error = rsb_insert(r, &ls->ls_rsbtbl); |
| if (error == -EEXIST) { |
| /* somebody else was faster and it seems the |
| * rsb exists now, we do a whole relookup |
| */ |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| dlm_free_rsb(r); |
| goto retry; |
| } else if (error) { |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| /* should never happen */ |
| dlm_free_rsb(r); |
| goto retry; |
| } |
| |
| list_add(&r->res_slow_list, &ls->ls_slow_inactive); |
| write_unlock_bh(&ls->ls_rsbtbl_lock); |
| |
| if (result) |
| *result = DLM_LU_ADD; |
| *r_nodeid = from_nodeid; |
| out: |
| return error; |
| } |
| |
| int dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, const char *name, |
| int len, unsigned int flags, int *r_nodeid, int *result) |
| { |
| int rv; |
| rcu_read_lock(); |
| rv = _dlm_master_lookup(ls, from_nodeid, name, len, flags, r_nodeid, result); |
| rcu_read_unlock(); |
| return rv; |
| } |
| |
| static void dlm_dump_rsb_hash(struct dlm_ls *ls, uint32_t hash) |
| { |
| struct dlm_rsb *r; |
| |
| read_lock_bh(&ls->ls_rsbtbl_lock); |
| list_for_each_entry(r, &ls->ls_slow_active, res_slow_list) { |
| if (r->res_hash == hash) |
| dlm_dump_rsb(r); |
| } |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| } |
| |
| void dlm_dump_rsb_name(struct dlm_ls *ls, const char *name, int len) |
| { |
| struct dlm_rsb *r = NULL; |
| int error; |
| |
| read_lock_bh(&ls->ls_rsbtbl_lock); |
| error = dlm_search_rsb_tree(&ls->ls_rsbtbl, name, len, &r); |
| if (!error) |
| goto out; |
| |
| dlm_dump_rsb(r); |
| out: |
| read_unlock_bh(&ls->ls_rsbtbl_lock); |
| } |
| |
| static void deactivate_rsb(struct kref *kref) |
| { |
| struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref); |
| struct dlm_ls *ls = r->res_ls; |
| int our_nodeid = dlm_our_nodeid(); |
| |
| DLM_ASSERT(list_empty(&r->res_root_list), dlm_print_rsb(r);); |
| rsb_set_flag(r, RSB_INACTIVE); |
| list_move(&r->res_slow_list, &ls->ls_slow_inactive); |
| |
| /* |
| * When the rsb becomes unused: |
| * - If it's not a dir record for a remote master rsb, |
| * then it is put on the scan list to be freed. |
| * - If it's a dir record for a remote master rsb, |
| * then it is kept in the inactive state until |
| * receive_remove() from the master node. |
| */ |
| if (!dlm_no_directory(ls) && |
| (r->res_master_nodeid != our_nodeid) && |
| (dlm_dir_nodeid(r) != our_nodeid)) |
| add_scan(ls, r); |
| |
| if (r->res_lvbptr) { |
| dlm_free_lvb(r->res_lvbptr); |
| r->res_lvbptr = NULL; |
| } |
| } |
| |
| /* See comment for unhold_lkb */ |
| |
| static void unhold_rsb(struct dlm_rsb *r) |
| { |
| int rv; |
| |
| /* inactive rsbs are not ref counted */ |
| WARN_ON(rsb_flag(r, RSB_INACTIVE)); |
| rv = kref_put(&r->res_ref, deactivate_rsb); |
| DLM_ASSERT(!rv, dlm_dump_rsb(r);); |
| } |
| |
| void free_inactive_rsb(struct dlm_rsb *r) |
| { |
| WARN_ON_ONCE(!rsb_flag(r, RSB_INACTIVE)); |
| |
| DLM_ASSERT(list_empty(&r->res_lookup), dlm_dump_rsb(r);); |
| DLM_ASSERT(list_empty(&r->res_grantqueue), dlm_dump_rsb(r);); |
| DLM_ASSERT(list_empty(&r->res_convertqueue), dlm_dump_rsb(r);); |
| DLM_ASSERT(list_empty(&r->res_waitqueue), dlm_dump_rsb(r);); |
| DLM_ASSERT(list_empty(&r->res_root_list), dlm_dump_rsb(r);); |
| DLM_ASSERT(list_empty(&r->res_scan_list), dlm_dump_rsb(r);); |
| DLM_ASSERT(list_empty(&r->res_recover_list), dlm_dump_rsb(r);); |
| DLM_ASSERT(list_empty(&r->res_masters_list), dlm_dump_rsb(r);); |
| |
| dlm_free_rsb(r); |
| } |
| |
| /* Attaching/detaching lkb's from rsb's is for rsb reference counting. |
| The rsb must exist as long as any lkb's for it do. */ |
| |
| static void attach_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| hold_rsb(r); |
| lkb->lkb_resource = r; |
| } |
| |
| static void detach_lkb(struct dlm_lkb *lkb) |
| { |
| if (lkb->lkb_resource) { |
| put_rsb(lkb->lkb_resource); |
| lkb->lkb_resource = NULL; |
| } |
| } |
| |
| static int _create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret, |
| unsigned long start, unsigned long end) |
| { |
| struct xa_limit limit; |
| struct dlm_lkb *lkb; |
| int rv; |
| |
| limit.max = end; |
| limit.min = start; |
| |
| lkb = dlm_allocate_lkb(ls); |
| if (!lkb) |
| return -ENOMEM; |
| |
| lkb->lkb_last_bast_cb_mode = DLM_LOCK_IV; |
| lkb->lkb_last_cast_cb_mode = DLM_LOCK_IV; |
| lkb->lkb_last_cb_mode = DLM_LOCK_IV; |
| lkb->lkb_nodeid = -1; |
| lkb->lkb_grmode = DLM_LOCK_IV; |
| kref_init(&lkb->lkb_ref); |
| INIT_LIST_HEAD(&lkb->lkb_ownqueue); |
| INIT_LIST_HEAD(&lkb->lkb_rsb_lookup); |
| |
| write_lock_bh(&ls->ls_lkbxa_lock); |
| rv = xa_alloc(&ls->ls_lkbxa, &lkb->lkb_id, lkb, limit, GFP_ATOMIC); |
| write_unlock_bh(&ls->ls_lkbxa_lock); |
| |
| if (rv < 0) { |
| log_error(ls, "create_lkb xa error %d", rv); |
| dlm_free_lkb(lkb); |
| return rv; |
| } |
| |
| *lkb_ret = lkb; |
| return 0; |
| } |
| |
| static int create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret) |
| { |
| return _create_lkb(ls, lkb_ret, 1, ULONG_MAX); |
| } |
| |
| static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret) |
| { |
| struct dlm_lkb *lkb; |
| |
| read_lock_bh(&ls->ls_lkbxa_lock); |
| lkb = xa_load(&ls->ls_lkbxa, lkid); |
| if (lkb) |
| kref_get(&lkb->lkb_ref); |
| read_unlock_bh(&ls->ls_lkbxa_lock); |
| |
| *lkb_ret = lkb; |
| return lkb ? 0 : -ENOENT; |
| } |
| |
| static void kill_lkb(struct kref *kref) |
| { |
| struct dlm_lkb *lkb = container_of(kref, struct dlm_lkb, lkb_ref); |
| |
| /* All work is done after the return from kref_put() so we |
| can release the write_lock before the detach_lkb */ |
| |
| DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb);); |
| } |
| |
| /* __put_lkb() is used when an lkb may not have an rsb attached to |
| it so we need to provide the lockspace explicitly */ |
| |
| static int __put_lkb(struct dlm_ls *ls, struct dlm_lkb *lkb) |
| { |
| uint32_t lkid = lkb->lkb_id; |
| int rv; |
| |
| rv = dlm_kref_put_write_lock_bh(&lkb->lkb_ref, kill_lkb, |
| &ls->ls_lkbxa_lock); |
| if (rv) { |
| xa_erase(&ls->ls_lkbxa, lkid); |
| write_unlock_bh(&ls->ls_lkbxa_lock); |
| |
| detach_lkb(lkb); |
| |
| /* for local/process lkbs, lvbptr points to caller's lksb */ |
| if (lkb->lkb_lvbptr && is_master_copy(lkb)) |
| dlm_free_lvb(lkb->lkb_lvbptr); |
| dlm_free_lkb(lkb); |
| } |
| |
| return rv; |
| } |
| |
| int dlm_put_lkb(struct dlm_lkb *lkb) |
| { |
| struct dlm_ls *ls; |
| |
| DLM_ASSERT(lkb->lkb_resource, dlm_print_lkb(lkb);); |
| DLM_ASSERT(lkb->lkb_resource->res_ls, dlm_print_lkb(lkb);); |
| |
| ls = lkb->lkb_resource->res_ls; |
| return __put_lkb(ls, lkb); |
| } |
| |
| /* This is only called to add a reference when the code already holds |
| a valid reference to the lkb, so there's no need for locking. */ |
| |
| static inline void hold_lkb(struct dlm_lkb *lkb) |
| { |
| kref_get(&lkb->lkb_ref); |
| } |
| |
| static void unhold_lkb_assert(struct kref *kref) |
| { |
| struct dlm_lkb *lkb = container_of(kref, struct dlm_lkb, lkb_ref); |
| |
| DLM_ASSERT(false, dlm_print_lkb(lkb);); |
| } |
| |
| /* This is called when we need to remove a reference and are certain |
| it's not the last ref. e.g. del_lkb is always called between a |
| find_lkb/put_lkb and is always the inverse of a previous add_lkb. |
| put_lkb would work fine, but would involve unnecessary locking */ |
| |
| static inline void unhold_lkb(struct dlm_lkb *lkb) |
| { |
| kref_put(&lkb->lkb_ref, unhold_lkb_assert); |
| } |
| |
| static void lkb_add_ordered(struct list_head *new, struct list_head *head, |
| int mode) |
| { |
| struct dlm_lkb *lkb = NULL, *iter; |
| |
| list_for_each_entry(iter, head, lkb_statequeue) |
| if (iter->lkb_rqmode < mode) { |
| lkb = iter; |
| list_add_tail(new, &iter->lkb_statequeue); |
| break; |
| } |
| |
| if (!lkb) |
| list_add_tail(new, head); |
| } |
| |
| /* add/remove lkb to rsb's grant/convert/wait queue */ |
| |
| static void add_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb, int status) |
| { |
| kref_get(&lkb->lkb_ref); |
| |
| DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb);); |
| |
| lkb->lkb_timestamp = ktime_get(); |
| |
| lkb->lkb_status = status; |
| |
| switch (status) { |
| case DLM_LKSTS_WAITING: |
| if (lkb->lkb_exflags & DLM_LKF_HEADQUE) |
| list_add(&lkb->lkb_statequeue, &r->res_waitqueue); |
| else |
| list_add_tail(&lkb->lkb_statequeue, &r->res_waitqueue); |
| break; |
| case DLM_LKSTS_GRANTED: |
| /* convention says granted locks kept in order of grmode */ |
| lkb_add_ordered(&lkb->lkb_statequeue, &r->res_grantqueue, |
| lkb->lkb_grmode); |
| break; |
| case DLM_LKSTS_CONVERT: |
| if (lkb->lkb_exflags & DLM_LKF_HEADQUE) |
| list_add(&lkb->lkb_statequeue, &r->res_convertqueue); |
| else |
| list_add_tail(&lkb->lkb_statequeue, |
| &r->res_convertqueue); |
| break; |
| default: |
| DLM_ASSERT(0, dlm_print_lkb(lkb); printk("sts=%d\n", status);); |
| } |
| } |
| |
| static void del_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| lkb->lkb_status = 0; |
| list_del(&lkb->lkb_statequeue); |
| unhold_lkb(lkb); |
| } |
| |
| static void move_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb, int sts) |
| { |
| hold_lkb(lkb); |
| del_lkb(r, lkb); |
| add_lkb(r, lkb, sts); |
| unhold_lkb(lkb); |
| } |
| |
| static int msg_reply_type(int mstype) |
| { |
| switch (mstype) { |
| case DLM_MSG_REQUEST: |
| return DLM_MSG_REQUEST_REPLY; |
| case DLM_MSG_CONVERT: |
| return DLM_MSG_CONVERT_REPLY; |
| case DLM_MSG_UNLOCK: |
| return DLM_MSG_UNLOCK_REPLY; |
| case DLM_MSG_CANCEL: |
| return DLM_MSG_CANCEL_REPLY; |
| case DLM_MSG_LOOKUP: |
| return DLM_MSG_LOOKUP_REPLY; |
| } |
| return -1; |
| } |
| |
| /* add/remove lkb from global waiters list of lkb's waiting for |
| a reply from a remote node */ |
| |
| static int add_to_waiters(struct dlm_lkb *lkb, int mstype, int to_nodeid) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int error = 0; |
| |
| spin_lock_bh(&ls->ls_waiters_lock); |
| |
| if (is_overlap_unlock(lkb) || |
| (is_overlap_cancel(lkb) && (mstype == DLM_MSG_CANCEL))) { |
| error = -EINVAL; |
| goto out; |
| } |
| |
| if (lkb->lkb_wait_type || is_overlap_cancel(lkb)) { |
| switch (mstype) { |
| case DLM_MSG_UNLOCK: |
| set_bit(DLM_IFL_OVERLAP_UNLOCK_BIT, &lkb->lkb_iflags); |
| break; |
| case DLM_MSG_CANCEL: |
| set_bit(DLM_IFL_OVERLAP_CANCEL_BIT, &lkb->lkb_iflags); |
| break; |
| default: |
| error = -EBUSY; |
| goto out; |
| } |
| lkb->lkb_wait_count++; |
| hold_lkb(lkb); |
| |
| log_debug(ls, "addwait %x cur %d overlap %d count %d f %x", |
| lkb->lkb_id, lkb->lkb_wait_type, mstype, |
| lkb->lkb_wait_count, dlm_iflags_val(lkb)); |
| goto out; |
| } |
| |
| DLM_ASSERT(!lkb->lkb_wait_count, |
| dlm_print_lkb(lkb); |
| printk("wait_count %d\n", lkb->lkb_wait_count);); |
| |
| lkb->lkb_wait_count++; |
| lkb->lkb_wait_type = mstype; |
| lkb->lkb_wait_nodeid = to_nodeid; /* for debugging */ |
| hold_lkb(lkb); |
| list_add(&lkb->lkb_wait_reply, &ls->ls_waiters); |
| out: |
| if (error) |
| log_error(ls, "addwait error %x %d flags %x %d %d %s", |
| lkb->lkb_id, error, dlm_iflags_val(lkb), mstype, |
| lkb->lkb_wait_type, lkb->lkb_resource->res_name); |
| spin_unlock_bh(&ls->ls_waiters_lock); |
| return error; |
| } |
| |
| /* We clear the RESEND flag because we might be taking an lkb off the waiters |
| list as part of process_requestqueue (e.g. a lookup that has an optimized |
| request reply on the requestqueue) between dlm_recover_waiters_pre() which |
| set RESEND and dlm_recover_waiters_post() */ |
| |
| static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype, |
| const struct dlm_message *ms) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int overlap_done = 0; |
| |
| if (mstype == DLM_MSG_UNLOCK_REPLY && |
| test_and_clear_bit(DLM_IFL_OVERLAP_UNLOCK_BIT, &lkb->lkb_iflags)) { |
| log_debug(ls, "remwait %x unlock_reply overlap", lkb->lkb_id); |
| overlap_done = 1; |
| goto out_del; |
| } |
| |
| if (mstype == DLM_MSG_CANCEL_REPLY && |
| test_and_clear_bit(DLM_IFL_OVERLAP_CANCEL_BIT, &lkb->lkb_iflags)) { |
| log_debug(ls, "remwait %x cancel_reply overlap", lkb->lkb_id); |
| overlap_done = 1; |
| goto out_del; |
| } |
| |
| /* Cancel state was preemptively cleared by a successful convert, |
| see next comment, nothing to do. */ |
| |
| if ((mstype == DLM_MSG_CANCEL_REPLY) && |
| (lkb->lkb_wait_type != DLM_MSG_CANCEL)) { |
| log_debug(ls, "remwait %x cancel_reply wait_type %d", |
| lkb->lkb_id, lkb->lkb_wait_type); |
| return -1; |
| } |
| |
| /* Remove for the convert reply, and premptively remove for the |
| cancel reply. A convert has been granted while there's still |
| an outstanding cancel on it (the cancel is moot and the result |
| in the cancel reply should be 0). We preempt the cancel reply |
| because the app gets the convert result and then can follow up |
| with another op, like convert. This subsequent op would see the |
| lingering state of the cancel and fail with -EBUSY. */ |
| |
| if ((mstype == DLM_MSG_CONVERT_REPLY) && |
| (lkb->lkb_wait_type == DLM_MSG_CONVERT) && ms && !ms->m_result && |
| test_and_clear_bit(DLM_IFL_OVERLAP_CANCEL_BIT, &lkb->lkb_iflags)) { |
| log_debug(ls, "remwait %x convert_reply zap overlap_cancel", |
| lkb->lkb_id); |
| lkb->lkb_wait_type = 0; |
| lkb->lkb_wait_count--; |
| unhold_lkb(lkb); |
| goto out_del; |
| } |
| |
| /* N.B. type of reply may not always correspond to type of original |
| msg due to lookup->request optimization, verify others? */ |
| |
| if (lkb->lkb_wait_type) { |
| lkb->lkb_wait_type = 0; |
| goto out_del; |
| } |
| |
| log_error(ls, "remwait error %x remote %d %x msg %d flags %x no wait", |
| lkb->lkb_id, ms ? le32_to_cpu(ms->m_header.h_nodeid) : 0, |
| lkb->lkb_remid, mstype, dlm_iflags_val(lkb)); |
| return -1; |
| |
| out_del: |
| /* the force-unlock/cancel has completed and we haven't recvd a reply |
| to the op that was in progress prior to the unlock/cancel; we |
| give up on any reply to the earlier op. FIXME: not sure when/how |
| this would happen */ |
| |
| if (overlap_done && lkb->lkb_wait_type) { |
| log_error(ls, "remwait error %x reply %d wait_type %d overlap", |
| lkb->lkb_id, mstype, lkb->lkb_wait_type); |
| lkb->lkb_wait_count--; |
| unhold_lkb(lkb); |
| lkb->lkb_wait_type = 0; |
| } |
| |
| DLM_ASSERT(lkb->lkb_wait_count, dlm_print_lkb(lkb);); |
| |
| clear_bit(DLM_IFL_RESEND_BIT, &lkb->lkb_iflags); |
| lkb->lkb_wait_count--; |
| if (!lkb->lkb_wait_count) |
| list_del_init(&lkb->lkb_wait_reply); |
| unhold_lkb(lkb); |
| return 0; |
| } |
| |
| static int remove_from_waiters(struct dlm_lkb *lkb, int mstype) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int error; |
| |
| spin_lock_bh(&ls->ls_waiters_lock); |
| error = _remove_from_waiters(lkb, mstype, NULL); |
| spin_unlock_bh(&ls->ls_waiters_lock); |
| return error; |
| } |
| |
| /* Handles situations where we might be processing a "fake" or "local" reply in |
| * the recovery context which stops any locking activity. Only debugfs might |
| * change the lockspace waiters but they will held the recovery lock to ensure |
| * remove_from_waiters_ms() in local case will be the only user manipulating the |
| * lockspace waiters in recovery context. |
| */ |
| |
| static int remove_from_waiters_ms(struct dlm_lkb *lkb, |
| const struct dlm_message *ms, bool local) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int error; |
| |
| if (!local) |
| spin_lock_bh(&ls->ls_waiters_lock); |
| else |
| WARN_ON_ONCE(!rwsem_is_locked(&ls->ls_in_recovery) || |
| !dlm_locking_stopped(ls)); |
| error = _remove_from_waiters(lkb, le32_to_cpu(ms->m_type), ms); |
| if (!local) |
| spin_unlock_bh(&ls->ls_waiters_lock); |
| return error; |
| } |
| |
| /* lkb is master or local copy */ |
| |
| static void set_lvb_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int b, len = r->res_ls->ls_lvblen; |
| |
| /* b=1 lvb returned to caller |
| b=0 lvb written to rsb or invalidated |
| b=-1 do nothing */ |
| |
| b = dlm_lvb_operations[lkb->lkb_grmode + 1][lkb->lkb_rqmode + 1]; |
| |
| if (b == 1) { |
| if (!lkb->lkb_lvbptr) |
| return; |
| |
| if (!(lkb->lkb_exflags & DLM_LKF_VALBLK)) |
| return; |
| |
| if (!r->res_lvbptr) |
| return; |
| |
| memcpy(lkb->lkb_lvbptr, r->res_lvbptr, len); |
| lkb->lkb_lvbseq = r->res_lvbseq; |
| |
| } else if (b == 0) { |
| if (lkb->lkb_exflags & DLM_LKF_IVVALBLK) { |
| rsb_set_flag(r, RSB_VALNOTVALID); |
| return; |
| } |
| |
| if (!lkb->lkb_lvbptr) |
| return; |
| |
| if (!(lkb->lkb_exflags & DLM_LKF_VALBLK)) |
| return; |
| |
| if (!r->res_lvbptr) |
| r->res_lvbptr = dlm_allocate_lvb(r->res_ls); |
| |
| if (!r->res_lvbptr) |
| return; |
| |
| memcpy(r->res_lvbptr, lkb->lkb_lvbptr, len); |
| r->res_lvbseq++; |
| lkb->lkb_lvbseq = r->res_lvbseq; |
| rsb_clear_flag(r, RSB_VALNOTVALID); |
| } |
| |
| if (rsb_flag(r, RSB_VALNOTVALID)) |
| set_bit(DLM_SBF_VALNOTVALID_BIT, &lkb->lkb_sbflags); |
| } |
| |
| static void set_lvb_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| if (lkb->lkb_grmode < DLM_LOCK_PW) |
| return; |
| |
| if (lkb->lkb_exflags & DLM_LKF_IVVALBLK) { |
| rsb_set_flag(r, RSB_VALNOTVALID); |
| return; |
| } |
| |
| if (!lkb->lkb_lvbptr) |
| return; |
| |
| if (!(lkb->lkb_exflags & DLM_LKF_VALBLK)) |
| return; |
| |
| if (!r->res_lvbptr) |
| r->res_lvbptr = dlm_allocate_lvb(r->res_ls); |
| |
| if (!r->res_lvbptr) |
| return; |
| |
| memcpy(r->res_lvbptr, lkb->lkb_lvbptr, r->res_ls->ls_lvblen); |
| r->res_lvbseq++; |
| rsb_clear_flag(r, RSB_VALNOTVALID); |
| } |
| |
| /* lkb is process copy (pc) */ |
| |
| static void set_lvb_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| const struct dlm_message *ms) |
| { |
| int b; |
| |
| if (!lkb->lkb_lvbptr) |
| return; |
| |
| if (!(lkb->lkb_exflags & DLM_LKF_VALBLK)) |
| return; |
| |
| b = dlm_lvb_operations[lkb->lkb_grmode + 1][lkb->lkb_rqmode + 1]; |
| if (b == 1) { |
| int len = receive_extralen(ms); |
| if (len > r->res_ls->ls_lvblen) |
| len = r->res_ls->ls_lvblen; |
| memcpy(lkb->lkb_lvbptr, ms->m_extra, len); |
| lkb->lkb_lvbseq = le32_to_cpu(ms->m_lvbseq); |
| } |
| } |
| |
| /* Manipulate lkb's on rsb's convert/granted/waiting queues |
| remove_lock -- used for unlock, removes lkb from granted |
| revert_lock -- used for cancel, moves lkb from convert to granted |
| grant_lock -- used for request and convert, adds lkb to granted or |
| moves lkb from convert or waiting to granted |
| |
| Each of these is used for master or local copy lkb's. There is |
| also a _pc() variation used to make the corresponding change on |
| a process copy (pc) lkb. */ |
| |
| static void _remove_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| del_lkb(r, lkb); |
| lkb->lkb_grmode = DLM_LOCK_IV; |
| /* this unhold undoes the original ref from create_lkb() |
| so this leads to the lkb being freed */ |
| unhold_lkb(lkb); |
| } |
| |
| static void remove_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| set_lvb_unlock(r, lkb); |
| _remove_lock(r, lkb); |
| } |
| |
| static void remove_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| _remove_lock(r, lkb); |
| } |
| |
| /* returns: 0 did nothing |
| 1 moved lock to granted |
| -1 removed lock */ |
| |
| static int revert_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int rv = 0; |
| |
| lkb->lkb_rqmode = DLM_LOCK_IV; |
| |
| switch (lkb->lkb_status) { |
| case DLM_LKSTS_GRANTED: |
| break; |
| case DLM_LKSTS_CONVERT: |
| move_lkb(r, lkb, DLM_LKSTS_GRANTED); |
| rv = 1; |
| break; |
| case DLM_LKSTS_WAITING: |
| del_lkb(r, lkb); |
| lkb->lkb_grmode = DLM_LOCK_IV; |
| /* this unhold undoes the original ref from create_lkb() |
| so this leads to the lkb being freed */ |
| unhold_lkb(lkb); |
| rv = -1; |
| break; |
| default: |
| log_print("invalid status for revert %d", lkb->lkb_status); |
| } |
| return rv; |
| } |
| |
| static int revert_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| return revert_lock(r, lkb); |
| } |
| |
| static void _grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| if (lkb->lkb_grmode != lkb->lkb_rqmode) { |
| lkb->lkb_grmode = lkb->lkb_rqmode; |
| if (lkb->lkb_status) |
| move_lkb(r, lkb, DLM_LKSTS_GRANTED); |
| else |
| add_lkb(r, lkb, DLM_LKSTS_GRANTED); |
| } |
| |
| lkb->lkb_rqmode = DLM_LOCK_IV; |
| lkb->lkb_highbast = 0; |
| } |
| |
| static void grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| set_lvb_lock(r, lkb); |
| _grant_lock(r, lkb); |
| } |
| |
| static void grant_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| const struct dlm_message *ms) |
| { |
| set_lvb_lock_pc(r, lkb, ms); |
| _grant_lock(r, lkb); |
| } |
| |
| /* called by grant_pending_locks() which means an async grant message must |
| be sent to the requesting node in addition to granting the lock if the |
| lkb belongs to a remote node. */ |
| |
| static void grant_lock_pending(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| grant_lock(r, lkb); |
| if (is_master_copy(lkb)) |
| send_grant(r, lkb); |
| else |
| queue_cast(r, lkb, 0); |
| } |
| |
| /* The special CONVDEADLK, ALTPR and ALTCW flags allow the master to |
| change the granted/requested modes. We're munging things accordingly in |
| the process copy. |
| CONVDEADLK: our grmode may have been forced down to NL to resolve a |
| conversion deadlock |
| ALTPR/ALTCW: our rqmode may have been changed to PR or CW to become |
| compatible with other granted locks */ |
| |
| static void munge_demoted(struct dlm_lkb *lkb) |
| { |
| if (lkb->lkb_rqmode == DLM_LOCK_IV || lkb->lkb_grmode == DLM_LOCK_IV) { |
| log_print("munge_demoted %x invalid modes gr %d rq %d", |
| lkb->lkb_id, lkb->lkb_grmode, lkb->lkb_rqmode); |
| return; |
| } |
| |
| lkb->lkb_grmode = DLM_LOCK_NL; |
| } |
| |
| static void munge_altmode(struct dlm_lkb *lkb, const struct dlm_message *ms) |
| { |
| if (ms->m_type != cpu_to_le32(DLM_MSG_REQUEST_REPLY) && |
| ms->m_type != cpu_to_le32(DLM_MSG_GRANT)) { |
| log_print("munge_altmode %x invalid reply type %d", |
| lkb->lkb_id, le32_to_cpu(ms->m_type)); |
| return; |
| } |
| |
| if (lkb->lkb_exflags & DLM_LKF_ALTPR) |
| lkb->lkb_rqmode = DLM_LOCK_PR; |
| else if (lkb->lkb_exflags & DLM_LKF_ALTCW) |
| lkb->lkb_rqmode = DLM_LOCK_CW; |
| else { |
| log_print("munge_altmode invalid exflags %x", lkb->lkb_exflags); |
| dlm_print_lkb(lkb); |
| } |
| } |
| |
| static inline int first_in_list(struct dlm_lkb *lkb, struct list_head *head) |
| { |
| struct dlm_lkb *first = list_entry(head->next, struct dlm_lkb, |
| lkb_statequeue); |
| if (lkb->lkb_id == first->lkb_id) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* Check if the given lkb conflicts with another lkb on the queue. */ |
| |
| static int queue_conflict(struct list_head *head, struct dlm_lkb *lkb) |
| { |
| struct dlm_lkb *this; |
| |
| list_for_each_entry(this, head, lkb_statequeue) { |
| if (this == lkb) |
| continue; |
| if (!modes_compat(this, lkb)) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * "A conversion deadlock arises with a pair of lock requests in the converting |
| * queue for one resource. The granted mode of each lock blocks the requested |
| * mode of the other lock." |
| * |
| * Part 2: if the granted mode of lkb is preventing an earlier lkb in the |
| * convert queue from being granted, then deadlk/demote lkb. |
| * |
| * Example: |
| * Granted Queue: empty |
| * Convert Queue: NL->EX (first lock) |
| * PR->EX (second lock) |
| * |
| * The first lock can't be granted because of the granted mode of the second |
| * lock and the second lock can't be granted because it's not first in the |
| * list. We either cancel lkb's conversion (PR->EX) and return EDEADLK, or we |
| * demote the granted mode of lkb (from PR to NL) if it has the CONVDEADLK |
| * flag set and return DEMOTED in the lksb flags. |
| * |
| * Originally, this function detected conv-deadlk in a more limited scope: |
| * - if !modes_compat(lkb1, lkb2) && !modes_compat(lkb2, lkb1), or |
| * - if lkb1 was the first entry in the queue (not just earlier), and was |
| * blocked by the granted mode of lkb2, and there was nothing on the |
| * granted queue preventing lkb1 from being granted immediately, i.e. |
| * lkb2 was the only thing preventing lkb1 from being granted. |
| * |
| * That second condition meant we'd only say there was conv-deadlk if |
| * resolving it (by demotion) would lead to the first lock on the convert |
| * queue being granted right away. It allowed conversion deadlocks to exist |
| * between locks on the convert queue while they couldn't be granted anyway. |
| * |
| * Now, we detect and take action on conversion deadlocks immediately when |
| * they're created, even if they may not be immediately consequential. If |
| * lkb1 exists anywhere in the convert queue and lkb2 comes in with a granted |
| * mode that would prevent lkb1's conversion from being granted, we do a |
| * deadlk/demote on lkb2 right away and don't let it onto the convert queue. |
| * I think this means that the lkb_is_ahead condition below should always |
| * be zero, i.e. there will never be conv-deadlk between two locks that are |
| * both already on the convert queue. |
| */ |
| |
| static int conversion_deadlock_detect(struct dlm_rsb *r, struct dlm_lkb *lkb2) |
| { |
| struct dlm_lkb *lkb1; |
| int lkb_is_ahead = 0; |
| |
| list_for_each_entry(lkb1, &r->res_convertqueue, lkb_statequeue) { |
| if (lkb1 == lkb2) { |
| lkb_is_ahead = 1; |
| continue; |
| } |
| |
| if (!lkb_is_ahead) { |
| if (!modes_compat(lkb2, lkb1)) |
| return 1; |
| } else { |
| if (!modes_compat(lkb2, lkb1) && |
| !modes_compat(lkb1, lkb2)) |
| return 1; |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * Return 1 if the lock can be granted, 0 otherwise. |
| * Also detect and resolve conversion deadlocks. |
| * |
| * lkb is the lock to be granted |
| * |
| * now is 1 if the function is being called in the context of the |
| * immediate request, it is 0 if called later, after the lock has been |
| * queued. |
| * |
| * recover is 1 if dlm_recover_grant() is trying to grant conversions |
| * after recovery. |
| * |
| * References are from chapter 6 of "VAXcluster Principles" by Roy Davis |
| */ |
| |
| static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now, |
| int recover) |
| { |
| int8_t conv = (lkb->lkb_grmode != DLM_LOCK_IV); |
| |
| /* |
| * 6-10: Version 5.4 introduced an option to address the phenomenon of |
| * a new request for a NL mode lock being blocked. |
| * |
| * 6-11: If the optional EXPEDITE flag is used with the new NL mode |
| * request, then it would be granted. In essence, the use of this flag |
| * tells the Lock Manager to expedite theis request by not considering |
| * what may be in the CONVERTING or WAITING queues... As of this |
| * writing, the EXPEDITE flag can be used only with new requests for NL |
| * mode locks. This flag is not valid for conversion requests. |
| * |
| * A shortcut. Earlier checks return an error if EXPEDITE is used in a |
| * conversion or used with a non-NL requested mode. We also know an |
| * EXPEDITE request is always granted immediately, so now must always |
| * be 1. The full condition to grant an expedite request: (now && |
| * !conv && lkb->rqmode == DLM_LOCK_NL && (flags & EXPEDITE)) can |
| * therefore be shortened to just checking the flag. |
| */ |
| |
| if (lkb->lkb_exflags & DLM_LKF_EXPEDITE) |
| return 1; |
| |
| /* |
| * A shortcut. Without this, !queue_conflict(grantqueue, lkb) would be |
| * added to the remaining conditions. |
| */ |
| |
| if (queue_conflict(&r->res_grantqueue, lkb)) |
| return 0; |
| |
| /* |
| * 6-3: By default, a conversion request is immediately granted if the |
| * requested mode is compatible with the modes of all other granted |
| * locks |
| */ |
| |
| if (queue_conflict(&r->res_convertqueue, lkb)) |
| return 0; |
| |
| /* |
| * The RECOVER_GRANT flag means dlm_recover_grant() is granting |
| * locks for a recovered rsb, on which lkb's have been rebuilt. |
| * The lkb's may have been rebuilt on the queues in a different |
| * order than they were in on the previous master. So, granting |
| * queued conversions in order after recovery doesn't make sense |
| * since the order hasn't been preserved anyway. The new order |
| * could also have created a new "in place" conversion deadlock. |
| * (e.g. old, failed master held granted EX, with PR->EX, NL->EX. |
| * After recovery, there would be no granted locks, and possibly |
| * NL->EX, PR->EX, an in-place conversion deadlock.) So, after |
| * recovery, grant conversions without considering order. |
| */ |
| |
| if (conv && recover) |
| return 1; |
| |
| /* |
| * 6-5: But the default algorithm for deciding whether to grant or |
| * queue conversion requests does not by itself guarantee that such |
| * requests are serviced on a "first come first serve" basis. This, in |
| * turn, can lead to a phenomenon known as "indefinate postponement". |
| * |
| * 6-7: This issue is dealt with by using the optional QUECVT flag with |
| * the system service employed to request a lock conversion. This flag |
| * forces certain conversion requests to be queued, even if they are |
| * compatible with the granted modes of other locks on the same |
| * resource. Thus, the use of this flag results in conversion requests |
| * being ordered on a "first come first servce" basis. |
| * |
| * DCT: This condition is all about new conversions being able to occur |
| * "in place" while the lock remains on the granted queue (assuming |
| * nothing else conflicts.) IOW if QUECVT isn't set, a conversion |
| * doesn't _have_ to go onto the convert queue where it's processed in |
| * order. The "now" variable is necessary to distinguish converts |
| * being received and processed for the first time now, because once a |
| * convert is moved to the conversion queue the condition below applies |
| * requiring fifo granting. |
| */ |
| |
| if (now && conv && !(lkb->lkb_exflags & DLM_LKF_QUECVT)) |
| return 1; |
| |
| /* |
| * Even if the convert is compat with all granted locks, |
| * QUECVT forces it behind other locks on the convert queue. |
| */ |
| |
| if (now && conv && (lkb->lkb_exflags & DLM_LKF_QUECVT)) { |
| if (list_empty(&r->res_convertqueue)) |
| return 1; |
| else |
| return 0; |
| } |
| |
| /* |
| * The NOORDER flag is set to avoid the standard vms rules on grant |
| * order. |
| */ |
| |
| if (lkb->lkb_exflags & DLM_LKF_NOORDER) |
| return 1; |
| |
| /* |
| * 6-3: Once in that queue [CONVERTING], a conversion request cannot be |
| * granted until all other conversion requests ahead of it are granted |
| * and/or canceled. |
| */ |
| |
| if (!now && conv && first_in_list(lkb, &r->res_convertqueue)) |
| return 1; |
| |
| /* |
| * 6-4: By default, a new request is immediately granted only if all |
| * three of the following conditions are satisfied when the request is |
| * issued: |
| * - The queue of ungranted conversion requests for the resource is |
| * empty. |
| * - The queue of ungranted new requests for the resource is empty. |
| * - The mode of the new request is compatible with the most |
| * restrictive mode of all granted locks on the resource. |
| */ |
| |
| if (now && !conv && list_empty(&r->res_convertqueue) && |
| list_empty(&r->res_waitqueue)) |
| return 1; |
| |
| /* |
| * 6-4: Once a lock request is in the queue of ungranted new requests, |
| * it cannot be granted until the queue of ungranted conversion |
| * requests is empty, all ungranted new requests ahead of it are |
| * granted and/or canceled, and it is compatible with the granted mode |
| * of the most restrictive lock granted on the resource. |
| */ |
| |
| if (!now && !conv && list_empty(&r->res_convertqueue) && |
| first_in_list(lkb, &r->res_waitqueue)) |
| return 1; |
| |
| return 0; |
| } |
| |
| static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now, |
| int recover, int *err) |
| { |
| int rv; |
| int8_t alt = 0, rqmode = lkb->lkb_rqmode; |
| int8_t is_convert = (lkb->lkb_grmode != DLM_LOCK_IV); |
| |
| if (err) |
| *err = 0; |
| |
| rv = _can_be_granted(r, lkb, now, recover); |
| if (rv) |
| goto out; |
| |
| /* |
| * The CONVDEADLK flag is non-standard and tells the dlm to resolve |
| * conversion deadlocks by demoting grmode to NL, otherwise the dlm |
| * cancels one of the locks. |
| */ |
| |
| if (is_convert && can_be_queued(lkb) && |
| conversion_deadlock_detect(r, lkb)) { |
| if (lkb->lkb_exflags & DLM_LKF_CONVDEADLK) { |
| lkb->lkb_grmode = DLM_LOCK_NL; |
| set_bit(DLM_SBF_DEMOTED_BIT, &lkb->lkb_sbflags); |
| } else if (err) { |
| *err = -EDEADLK; |
| } else { |
| log_print("can_be_granted deadlock %x now %d", |
| lkb->lkb_id, now); |
| dlm_dump_rsb(r); |
| } |
| goto out; |
| } |
| |
| /* |
| * The ALTPR and ALTCW flags are non-standard and tell the dlm to try |
| * to grant a request in a mode other than the normal rqmode. It's a |
| * simple way to provide a big optimization to applications that can |
| * use them. |
| */ |
| |
| if (rqmode != DLM_LOCK_PR && (lkb->lkb_exflags & DLM_LKF_ALTPR)) |
| alt = DLM_LOCK_PR; |
| else if (rqmode != DLM_LOCK_CW && (lkb->lkb_exflags & DLM_LKF_ALTCW)) |
| alt = DLM_LOCK_CW; |
| |
| if (alt) { |
| lkb->lkb_rqmode = alt; |
| rv = _can_be_granted(r, lkb, now, 0); |
| if (rv) |
| set_bit(DLM_SBF_ALTMODE_BIT, &lkb->lkb_sbflags); |
| else |
| lkb->lkb_rqmode = rqmode; |
| } |
| out: |
| return rv; |
| } |
| |
| /* Returns the highest requested mode of all blocked conversions; sets |
| cw if there's a blocked conversion to DLM_LOCK_CW. */ |
| |
| static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw, |
| unsigned int *count) |
| { |
| struct dlm_lkb *lkb, *s; |
| int recover = rsb_flag(r, RSB_RECOVER_GRANT); |
| int hi, demoted, quit, grant_restart, demote_restart; |
| int deadlk; |
| |
| quit = 0; |
| restart: |
| grant_restart = 0; |
| demote_restart = 0; |
| hi = DLM_LOCK_IV; |
| |
| list_for_each_entry_safe(lkb, s, &r->res_convertqueue, lkb_statequeue) { |
| demoted = is_demoted(lkb); |
| deadlk = 0; |
| |
| if (can_be_granted(r, lkb, 0, recover, &deadlk)) { |
| grant_lock_pending(r, lkb); |
| grant_restart = 1; |
| if (count) |
| (*count)++; |
| continue; |
| } |
| |
| if (!demoted && is_demoted(lkb)) { |
| log_print("WARN: pending demoted %x node %d %s", |
| lkb->lkb_id, lkb->lkb_nodeid, r->res_name); |
| demote_restart = 1; |
| continue; |
| } |
| |
| if (deadlk) { |
| /* |
| * If DLM_LKB_NODLKWT flag is set and conversion |
| * deadlock is detected, we request blocking AST and |
| * down (or cancel) conversion. |
| */ |
| if (lkb->lkb_exflags & DLM_LKF_NODLCKWT) { |
| if (lkb->lkb_highbast < lkb->lkb_rqmode) { |
| queue_bast(r, lkb, lkb->lkb_rqmode); |
| lkb->lkb_highbast = lkb->lkb_rqmode; |
| } |
| } else { |
| log_print("WARN: pending deadlock %x node %d %s", |
| lkb->lkb_id, lkb->lkb_nodeid, |
| r->res_name); |
| dlm_dump_rsb(r); |
| } |
| continue; |
| } |
| |
| hi = max_t(int, lkb->lkb_rqmode, hi); |
| |
| if (cw && lkb->lkb_rqmode == DLM_LOCK_CW) |
| *cw = 1; |
| } |
| |
| if (grant_restart) |
| goto restart; |
| if (demote_restart && !quit) { |
| quit = 1; |
| goto restart; |
| } |
| |
| return max_t(int, high, hi); |
| } |
| |
| static int grant_pending_wait(struct dlm_rsb *r, int high, int *cw, |
| unsigned int *count) |
| { |
| struct dlm_lkb *lkb, *s; |
| |
| list_for_each_entry_safe(lkb, s, &r->res_waitqueue, lkb_statequeue) { |
| if (can_be_granted(r, lkb, 0, 0, NULL)) { |
| grant_lock_pending(r, lkb); |
| if (count) |
| (*count)++; |
| } else { |
| high = max_t(int, lkb->lkb_rqmode, high); |
| if (lkb->lkb_rqmode == DLM_LOCK_CW) |
| *cw = 1; |
| } |
| } |
| |
| return high; |
| } |
| |
| /* cw of 1 means there's a lock with a rqmode of DLM_LOCK_CW that's blocked |
| on either the convert or waiting queue. |
| high is the largest rqmode of all locks blocked on the convert or |
| waiting queue. */ |
| |
| static int lock_requires_bast(struct dlm_lkb *gr, int high, int cw) |
| { |
| if (gr->lkb_grmode == DLM_LOCK_PR && cw) { |
| if (gr->lkb_highbast < DLM_LOCK_EX) |
| return 1; |
| return 0; |
| } |
| |
| if (gr->lkb_highbast < high && |
| !__dlm_compat_matrix[gr->lkb_grmode+1][high+1]) |
| return 1; |
| return 0; |
| } |
| |
| static void grant_pending_locks(struct dlm_rsb *r, unsigned int *count) |
| { |
| struct dlm_lkb *lkb, *s; |
| int high = DLM_LOCK_IV; |
| int cw = 0; |
| |
| if (!is_master(r)) { |
| log_print("grant_pending_locks r nodeid %d", r->res_nodeid); |
| dlm_dump_rsb(r); |
| return; |
| } |
| |
| high = grant_pending_convert(r, high, &cw, count); |
| high = grant_pending_wait(r, high, &cw, count); |
| |
| if (high == DLM_LOCK_IV) |
| return; |
| |
| /* |
| * If there are locks left on the wait/convert queue then send blocking |
| * ASTs to granted locks based on the largest requested mode (high) |
| * found above. |
| */ |
| |
| list_for_each_entry_safe(lkb, s, &r->res_grantqueue, lkb_statequeue) { |
| if (lkb->lkb_bastfn && lock_requires_bast(lkb, high, cw)) { |
| if (cw && high == DLM_LOCK_PR && |
| lkb->lkb_grmode == DLM_LOCK_PR) |
| queue_bast(r, lkb, DLM_LOCK_CW); |
| else |
| queue_bast(r, lkb, high); |
| lkb->lkb_highbast = high; |
| } |
| } |
| } |
| |
| static int modes_require_bast(struct dlm_lkb *gr, struct dlm_lkb *rq) |
| { |
| if ((gr->lkb_grmode == DLM_LOCK_PR && rq->lkb_rqmode == DLM_LOCK_CW) || |
| (gr->lkb_grmode == DLM_LOCK_CW && rq->lkb_rqmode == DLM_LOCK_PR)) { |
| if (gr->lkb_highbast < DLM_LOCK_EX) |
| return 1; |
| return 0; |
| } |
| |
| if (gr->lkb_highbast < rq->lkb_rqmode && !modes_compat(gr, rq)) |
| return 1; |
| return 0; |
| } |
| |
| static void send_bast_queue(struct dlm_rsb *r, struct list_head *head, |
| struct dlm_lkb *lkb) |
| { |
| struct dlm_lkb *gr; |
| |
| list_for_each_entry(gr, head, lkb_statequeue) { |
| /* skip self when sending basts to convertqueue */ |
| if (gr == lkb) |
| continue; |
| if (gr->lkb_bastfn && modes_require_bast(gr, lkb)) { |
| queue_bast(r, gr, lkb->lkb_rqmode); |
| gr->lkb_highbast = lkb->lkb_rqmode; |
| } |
| } |
| } |
| |
| static void send_blocking_asts(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| send_bast_queue(r, &r->res_grantqueue, lkb); |
| } |
| |
| static void send_blocking_asts_all(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| send_bast_queue(r, &r->res_grantqueue, lkb); |
| send_bast_queue(r, &r->res_convertqueue, lkb); |
| } |
| |
| /* set_master(r, lkb) -- set the master nodeid of a resource |
| |
| The purpose of this function is to set the nodeid field in the given |
| lkb using the nodeid field in the given rsb. If the rsb's nodeid is |
| known, it can just be copied to the lkb and the function will return |
| 0. If the rsb's nodeid is _not_ known, it needs to be looked up |
| before it can be copied to the lkb. |
| |
| When the rsb nodeid is being looked up remotely, the initial lkb |
| causing the lookup is kept on the ls_waiters list waiting for the |
| lookup reply. Other lkb's waiting for the same rsb lookup are kept |
| on the rsb's res_lookup list until the master is verified. |
| |
| Return values: |
| 0: nodeid is set in rsb/lkb and the caller should go ahead and use it |
| 1: the rsb master is not available and the lkb has been placed on |
| a wait queue |
| */ |
| |
| static int set_master(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int our_nodeid = dlm_our_nodeid(); |
| |
| if (rsb_flag(r, RSB_MASTER_UNCERTAIN)) { |
| rsb_clear_flag(r, RSB_MASTER_UNCERTAIN); |
| r->res_first_lkid = lkb->lkb_id; |
| lkb->lkb_nodeid = r->res_nodeid; |
| return 0; |
| } |
| |
| if (r->res_first_lkid && r->res_first_lkid != lkb->lkb_id) { |
| list_add_tail(&lkb->lkb_rsb_lookup, &r->res_lookup); |
| return 1; |
| } |
| |
| if (r->res_master_nodeid == our_nodeid) { |
| lkb->lkb_nodeid = 0; |
| return 0; |
| } |
| |
| if (r->res_master_nodeid) { |
| lkb->lkb_nodeid = r->res_master_nodeid; |
| return 0; |
| } |
| |
| if (dlm_dir_nodeid(r) == our_nodeid) { |
| /* This is a somewhat unusual case; find_rsb will usually |
| have set res_master_nodeid when dir nodeid is local, but |
| there are cases where we become the dir node after we've |
| past find_rsb and go through _request_lock again. |
| confirm_master() or process_lookup_list() needs to be |
| called after this. */ |
| log_debug(r->res_ls, "set_master %x self master %d dir %d %s", |
| lkb->lkb_id, r->res_master_nodeid, r->res_dir_nodeid, |
| r->res_name); |
| r->res_master_nodeid = our_nodeid; |
| r->res_nodeid = 0; |
| lkb->lkb_nodeid = 0; |
| return 0; |
| } |
| |
| r->res_first_lkid = lkb->lkb_id; |
| send_lookup(r, lkb); |
| return 1; |
| } |
| |
| static void process_lookup_list(struct dlm_rsb *r) |
| { |
| struct dlm_lkb *lkb, *safe; |
| |
| list_for_each_entry_safe(lkb, safe, &r->res_lookup, lkb_rsb_lookup) { |
| list_del_init(&lkb->lkb_rsb_lookup); |
| _request_lock(r, lkb); |
| } |
| } |
| |
| /* confirm_master -- confirm (or deny) an rsb's master nodeid */ |
| |
| static void confirm_master(struct dlm_rsb *r, int error) |
| { |
| struct dlm_lkb *lkb; |
| |
| if (!r->res_first_lkid) |
| return; |
| |
| switch (error) { |
| case 0: |
| case -EINPROGRESS: |
| r->res_first_lkid = 0; |
| process_lookup_list(r); |
| break; |
| |
| case -EAGAIN: |
| case -EBADR: |
| case -ENOTBLK: |
| /* the remote request failed and won't be retried (it was |
| a NOQUEUE, or has been canceled/unlocked); make a waiting |
| lkb the first_lkid */ |
| |
| r->res_first_lkid = 0; |
| |
| if (!list_empty(&r->res_lookup)) { |
| lkb = list_entry(r->res_lookup.next, struct dlm_lkb, |
| lkb_rsb_lookup); |
| list_del_init(&lkb->lkb_rsb_lookup); |
| r->res_first_lkid = lkb->lkb_id; |
| _request_lock(r, lkb); |
| } |
| break; |
| |
| default: |
| log_error(r->res_ls, "confirm_master unknown error %d", error); |
| } |
| } |
| |
| static int set_lock_args(int mode, struct dlm_lksb *lksb, uint32_t flags, |
| int namelen, void (*ast)(void *astparam), |
| void *astparam, |
| void (*bast)(void *astparam, int mode), |
| struct dlm_args *args) |
| { |
| int rv = -EINVAL; |
| |
| /* check for invalid arg usage */ |
| |
| if (mode < 0 || mode > DLM_LOCK_EX) |
| goto out; |
| |
| if (!(flags & DLM_LKF_CONVERT) && (namelen > DLM_RESNAME_MAXLEN)) |
| goto out; |
| |
| if (flags & DLM_LKF_CANCEL) |
| goto out; |
| |
| if (flags & DLM_LKF_QUECVT && !(flags & DLM_LKF_CONVERT)) |
| goto out; |
| |
| if (flags & DLM_LKF_CONVDEADLK && !(flags & DLM_LKF_CONVERT)) |
| goto out; |
| |
| if (flags & DLM_LKF_CONVDEADLK && flags & DLM_LKF_NOQUEUE) |
| goto out; |
| |
| if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_CONVERT) |
| goto out; |
| |
| if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_QUECVT) |
| goto out; |
| |
| if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_NOQUEUE) |
| goto out; |
| |
| if (flags & DLM_LKF_EXPEDITE && mode != DLM_LOCK_NL) |
| goto out; |
| |
| if (!ast || !lksb) |
| goto out; |
| |
| if (flags & DLM_LKF_VALBLK && !lksb->sb_lvbptr) |
| goto out; |
| |
| if (flags & DLM_LKF_CONVERT && !lksb->sb_lkid) |
| goto out; |
| |
| /* these args will be copied to the lkb in validate_lock_args, |
| it cannot be done now because when converting locks, fields in |
| an active lkb cannot be modified before locking the rsb */ |
| |
| args->flags = flags; |
| args->astfn = ast; |
| args->astparam = astparam; |
| args->bastfn = bast; |
| args->mode = mode; |
| args->lksb = lksb; |
| rv = 0; |
| out: |
| return rv; |
| } |
| |
| static int set_unlock_args(uint32_t flags, void *astarg, struct dlm_args *args) |
| { |
| if (flags & ~(DLM_LKF_CANCEL | DLM_LKF_VALBLK | DLM_LKF_IVVALBLK | |
| DLM_LKF_FORCEUNLOCK)) |
| return -EINVAL; |
| |
| if (flags & DLM_LKF_CANCEL && flags & DLM_LKF_FORCEUNLOCK) |
| return -EINVAL; |
| |
| args->flags = flags; |
| args->astparam = astarg; |
| return 0; |
| } |
| |
| static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_args *args) |
| { |
| int rv = -EBUSY; |
| |
| if (args->flags & DLM_LKF_CONVERT) { |
| if (lkb->lkb_status != DLM_LKSTS_GRANTED) |
| goto out; |
| |
| /* lock not allowed if there's any op in progress */ |
| if (lkb->lkb_wait_type || lkb->lkb_wait_count) |
| goto out; |
| |
| if (is_overlap(lkb)) |
| goto out; |
| |
| rv = -EINVAL; |
| if (test_bit(DLM_IFL_MSTCPY_BIT, &lkb->lkb_iflags)) |
| goto out; |
| |
| if (args->flags & DLM_LKF_QUECVT && |
| !__quecvt_compat_matrix[lkb->lkb_grmode+1][args->mode+1]) |
| goto out; |
| } |
| |
| lkb->lkb_exflags = args->flags; |
| dlm_set_sbflags_val(lkb, 0); |
| lkb->lkb_astfn = args->astfn; |
| lkb->lkb_astparam = args->astparam; |
| lkb->lkb_bastfn = args->bastfn; |
| lkb->lkb_rqmode = args->mode; |
| lkb->lkb_lksb = args->lksb; |
| lkb->lkb_lvbptr = args->lksb->sb_lvbptr; |
| lkb->lkb_ownpid = (int) current->pid; |
| rv = 0; |
| out: |
| switch (rv) { |
| case 0: |
| break; |
| case -EINVAL: |
| /* annoy the user because dlm usage is wrong */ |
| WARN_ON(1); |
| log_error(ls, "%s %d %x %x %x %d %d %s", __func__, |
| rv, lkb->lkb_id, dlm_iflags_val(lkb), args->flags, |
| lkb->lkb_status, lkb->lkb_wait_type, |
| lkb->lkb_resource->res_name); |
| break; |
| default: |
| log_debug(ls, "%s %d %x %x %x %d %d %s", __func__, |
| rv, lkb->lkb_id, dlm_iflags_val(lkb), args->flags, |
| lkb->lkb_status, lkb->lkb_wait_type, |
| lkb->lkb_resource->res_name); |
| break; |
| } |
| |
| return rv; |
| } |
| |
| /* when dlm_unlock() sees -EBUSY with CANCEL/FORCEUNLOCK it returns 0 |
| for success */ |
| |
| /* note: it's valid for lkb_nodeid/res_nodeid to be -1 when we get here |
| because there may be a lookup in progress and it's valid to do |
| cancel/unlockf on it */ |
| |
| static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int rv = -EBUSY; |
| |
| /* normal unlock not allowed if there's any op in progress */ |
| if (!(args->flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK)) && |
| (lkb->lkb_wait_type || lkb->lkb_wait_count)) |
| goto out; |
| |
| /* an lkb may be waiting for an rsb lookup to complete where the |
| lookup was initiated by another lock */ |
| |
| if (!list_empty(&lkb->lkb_rsb_lookup)) { |
| if (args->flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK)) { |
| log_debug(ls, "unlock on rsb_lookup %x", lkb->lkb_id); |
| list_del_init(&lkb->lkb_rsb_lookup); |
| queue_cast(lkb->lkb_resource, lkb, |
| args->flags & DLM_LKF_CANCEL ? |
| -DLM_ECANCEL : -DLM_EUNLOCK); |
| unhold_lkb(lkb); /* undoes create_lkb() */ |
| } |
| /* caller changes -EBUSY to 0 for CANCEL and FORCEUNLOCK */ |
| goto out; |
| } |
| |
| rv = -EINVAL; |
| if (test_bit(DLM_IFL_MSTCPY_BIT, &lkb->lkb_iflags)) { |
| log_error(ls, "unlock on MSTCPY %x", lkb->lkb_id); |
| dlm_print_lkb(lkb); |
| goto out; |
| } |
| |
| /* an lkb may still exist even though the lock is EOL'ed due to a |
| * cancel, unlock or failed noqueue request; an app can't use these |
| * locks; return same error as if the lkid had not been found at all |
| */ |
| |
| if (test_bit(DLM_IFL_ENDOFLIFE_BIT, &lkb->lkb_iflags)) { |
| log_debug(ls, "unlock on ENDOFLIFE %x", lkb->lkb_id); |
| rv = -ENOENT; |
| goto out; |
| } |
| |
| /* cancel not allowed with another cancel/unlock in progress */ |
| |
| if (args->flags & DLM_LKF_CANCEL) { |
| if (lkb->lkb_exflags & DLM_LKF_CANCEL) |
| goto out; |
| |
| if (is_overlap(lkb)) |
| goto out; |
| |
| if (test_bit(DLM_IFL_RESEND_BIT, &lkb->lkb_iflags)) { |
| set_bit(DLM_IFL_OVERLAP_CANCEL_BIT, &lkb->lkb_iflags); |
| rv = -EBUSY; |
| goto out; |
| } |
| |
| /* there's nothing to cancel */ |
| if (lkb->lkb_status == DLM_LKSTS_GRANTED && |
| !lkb->lkb_wait_type) { |
| rv = -EBUSY; |
| goto out; |
| } |
| |
| switch (lkb->lkb_wait_type) { |
| case DLM_MSG_LOOKUP: |
| case DLM_MSG_REQUEST: |
| set_bit(DLM_IFL_OVERLAP_CANCEL_BIT, &lkb->lkb_iflags); |
| rv = -EBUSY; |
| goto out; |
| case DLM_MSG_UNLOCK: |
| case DLM_MSG_CANCEL: |
| goto out; |
| } |
| /* add_to_waiters() will set OVERLAP_CANCEL */ |
| goto out_ok; |
| } |
| |
| /* do we need to allow a force-unlock if there's a normal unlock |
| already in progress? in what conditions could the normal unlock |
| fail such that we'd want to send a force-unlock to be sure? */ |
| |
| if (args->flags & DLM_LKF_FORCEUNLOCK) { |
| if (lkb->lkb_exflags & DLM_LKF_FORCEUNLOCK) |
| goto out; |
| |
| if (is_overlap_unlock(lkb)) |
| goto out; |
| |
| if (test_bit(DLM_IFL_RESEND_BIT, &lkb->lkb_iflags)) { |
| set_bit(DLM_IFL_OVERLAP_UNLOCK_BIT, &lkb->lkb_iflags); |
| rv = -EBUSY; |
| goto out; |
| } |
| |
| switch (lkb->lkb_wait_type) { |
| case DLM_MSG_LOOKUP: |
| case DLM_MSG_REQUEST: |
| set_bit(DLM_IFL_OVERLAP_UNLOCK_BIT, &lkb->lkb_iflags); |
| rv = -EBUSY; |
| goto out; |
| case DLM_MSG_UNLOCK: |
| goto out; |
| } |
| /* add_to_waiters() will set OVERLAP_UNLOCK */ |
| } |
| |
| out_ok: |
| /* an overlapping op shouldn't blow away exflags from other op */ |
| lkb->lkb_exflags |= args->flags; |
| dlm_set_sbflags_val(lkb, 0); |
| lkb->lkb_astparam = args->astparam; |
| rv = 0; |
| out: |
| switch (rv) { |
| case 0: |
| break; |
| case -EINVAL: |
| /* annoy the user because dlm usage is wrong */ |
| WARN_ON(1); |
| log_error(ls, "%s %d %x %x %x %x %d %s", __func__, rv, |
| lkb->lkb_id, dlm_iflags_val(lkb), lkb->lkb_exflags, |
| args->flags, lkb->lkb_wait_type, |
| lkb->lkb_resource->res_name); |
| break; |
| default: |
| log_debug(ls, "%s %d %x %x %x %x %d %s", __func__, rv, |
| lkb->lkb_id, dlm_iflags_val(lkb), lkb->lkb_exflags, |
| args->flags, lkb->lkb_wait_type, |
| lkb->lkb_resource->res_name); |
| break; |
| } |
| |
| return rv; |
| } |
| |
| /* |
| * Four stage 4 varieties: |
| * do_request(), do_convert(), do_unlock(), do_cancel() |
| * These are called on the master node for the given lock and |
| * from the central locking logic. |
| */ |
| |
| static int do_request(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error = 0; |
| |
| if (can_be_granted(r, lkb, 1, 0, NULL)) { |
| grant_lock(r, lkb); |
| queue_cast(r, lkb, 0); |
| goto out; |
| } |
| |
| if (can_be_queued(lkb)) { |
| error = -EINPROGRESS; |
| add_lkb(r, lkb, DLM_LKSTS_WAITING); |
| goto out; |
| } |
| |
| error = -EAGAIN; |
| queue_cast(r, lkb, -EAGAIN); |
| out: |
| return error; |
| } |
| |
| static void do_request_effects(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| int error) |
| { |
| switch (error) { |
| case -EAGAIN: |
| if (force_blocking_asts(lkb)) |
| send_blocking_asts_all(r, lkb); |
| break; |
| case -EINPROGRESS: |
| send_blocking_asts(r, lkb); |
| break; |
| } |
| } |
| |
| static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error = 0; |
| int deadlk = 0; |
| |
| /* changing an existing lock may allow others to be granted */ |
| |
| if (can_be_granted(r, lkb, 1, 0, &deadlk)) { |
| grant_lock(r, lkb); |
| queue_cast(r, lkb, 0); |
| goto out; |
| } |
| |
| /* can_be_granted() detected that this lock would block in a conversion |
| deadlock, so we leave it on the granted queue and return EDEADLK in |
| the ast for the convert. */ |
| |
| if (deadlk && !(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) { |
| /* it's left on the granted queue */ |
| revert_lock(r, lkb); |
| queue_cast(r, lkb, -EDEADLK); |
| error = -EDEADLK; |
| goto out; |
| } |
| |
| /* is_demoted() means the can_be_granted() above set the grmode |
| to NL, and left us on the granted queue. This auto-demotion |
| (due to CONVDEADLK) might mean other locks, and/or this lock, are |
| now grantable. We have to try to grant other converting locks |
| before we try again to grant this one. */ |
| |
| if (is_demoted(lkb)) { |
| grant_pending_convert(r, DLM_LOCK_IV, NULL, NULL); |
| if (_can_be_granted(r, lkb, 1, 0)) { |
| grant_lock(r, lkb); |
| queue_cast(r, lkb, 0); |
| goto out; |
| } |
| /* else fall through and move to convert queue */ |
| } |
| |
| if (can_be_queued(lkb)) { |
| error = -EINPROGRESS; |
| del_lkb(r, lkb); |
| add_lkb(r, lkb, DLM_LKSTS_CONVERT); |
| goto out; |
| } |
| |
| error = -EAGAIN; |
| queue_cast(r, lkb, -EAGAIN); |
| out: |
| return error; |
| } |
| |
| static void do_convert_effects(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| int error) |
| { |
| switch (error) { |
| case 0: |
| grant_pending_locks(r, NULL); |
| /* grant_pending_locks also sends basts */ |
| break; |
| case -EAGAIN: |
| if (force_blocking_asts(lkb)) |
| send_blocking_asts_all(r, lkb); |
| break; |
| case -EINPROGRESS: |
| send_blocking_asts(r, lkb); |
| break; |
| } |
| } |
| |
| static int do_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| remove_lock(r, lkb); |
| queue_cast(r, lkb, -DLM_EUNLOCK); |
| return -DLM_EUNLOCK; |
| } |
| |
| static void do_unlock_effects(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| int error) |
| { |
| grant_pending_locks(r, NULL); |
| } |
| |
| /* returns: 0 did nothing, -DLM_ECANCEL canceled lock */ |
| |
| static int do_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| |