| /****************************************************************************** |
| ******************************************************************************* |
| ** |
| ** Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved. |
| ** |
| ** This copyrighted material is made available to anyone wishing to use, |
| ** modify, copy, or redistribute it subject to the terms and conditions |
| ** of the GNU General Public License v.2. |
| ** |
| ******************************************************************************* |
| ******************************************************************************/ |
| |
| /* Central locking logic has four stages: |
| |
| dlm_lock() |
| dlm_unlock() |
| |
| request_lock(ls, lkb) |
| convert_lock(ls, lkb) |
| unlock_lock(ls, lkb) |
| cancel_lock(ls, lkb) |
| |
| _request_lock(r, lkb) |
| _convert_lock(r, lkb) |
| _unlock_lock(r, lkb) |
| _cancel_lock(r, lkb) |
| |
| do_request(r, lkb) |
| do_convert(r, lkb) |
| do_unlock(r, lkb) |
| do_cancel(r, lkb) |
| |
| Stage 1 (lock, unlock) is mainly about checking input args and |
| splitting into one of the four main operations: |
| |
| dlm_lock = request_lock |
| dlm_lock+CONVERT = convert_lock |
| dlm_unlock = unlock_lock |
| dlm_unlock+CANCEL = cancel_lock |
| |
| Stage 2, xxxx_lock(), just finds and locks the relevant rsb which is |
| provided to the next stage. |
| |
| Stage 3, _xxxx_lock(), determines if the operation is local or remote. |
| When remote, it calls send_xxxx(), when local it calls do_xxxx(). |
| |
| Stage 4, do_xxxx(), is the guts of the operation. It manipulates the |
| given rsb and lkb and queues callbacks. |
| |
| For remote operations, send_xxxx() results in the corresponding do_xxxx() |
| function being executed on the remote node. The connecting send/receive |
| calls on local (L) and remote (R) nodes: |
| |
| L: send_xxxx() -> R: receive_xxxx() |
| R: do_xxxx() |
| L: receive_xxxx_reply() <- R: send_xxxx_reply() |
| */ |
| #include <linux/types.h> |
| #include "dlm_internal.h" |
| #include <linux/dlm_device.h> |
| #include "memory.h" |
| #include "lowcomms.h" |
| #include "requestqueue.h" |
| #include "util.h" |
| #include "dir.h" |
| #include "member.h" |
| #include "lockspace.h" |
| #include "ast.h" |
| #include "lock.h" |
| #include "rcom.h" |
| #include "recover.h" |
| #include "lvb_table.h" |
| #include "user.h" |
| #include "config.h" |
| |
| static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode); |
| static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static int send_remove(struct dlm_rsb *r); |
| static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb); |
| static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| struct dlm_message *ms); |
| static int receive_extralen(struct dlm_message *ms); |
| static void do_purge(struct dlm_ls *ls, int nodeid, int pid); |
| static void del_timeout(struct dlm_lkb *lkb); |
| |
| /* |
| * 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\n" |
| " status %d rqmode %d grmode %d wait_type %d ast_type %d\n", |
| lkb->lkb_nodeid, lkb->lkb_id, lkb->lkb_remid, lkb->lkb_exflags, |
| lkb->lkb_flags, lkb->lkb_status, lkb->lkb_rqmode, |
| lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_ast_type); |
| } |
| |
| void dlm_print_rsb(struct dlm_rsb *r) |
| { |
| printk(KERN_ERR "rsb: nodeid %d flags %lx first %x rlc %d name %s\n", |
| r->res_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 */ |
| |
| static inline 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 (lkb->lkb_sbflags & DLM_SBF_DEMOTED); |
| } |
| |
| static inline int is_altmode(struct dlm_lkb *lkb) |
| { |
| return (lkb->lkb_sbflags & DLM_SBF_ALTMODE); |
| } |
| |
| 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 && !(lkb->lkb_flags & DLM_IFL_MSTCPY)); |
| } |
| |
| static inline int is_master_copy(struct dlm_lkb *lkb) |
| { |
| if (lkb->lkb_flags & DLM_IFL_MSTCPY) |
| DLM_ASSERT(lkb->lkb_nodeid, dlm_print_lkb(lkb);); |
| return (lkb->lkb_flags & DLM_IFL_MSTCPY) ? 1 : 0; |
| } |
| |
| 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 lkb->lkb_flags & DLM_IFL_OVERLAP_UNLOCK; |
| } |
| |
| static inline int is_overlap_cancel(struct dlm_lkb *lkb) |
| { |
| return lkb->lkb_flags & DLM_IFL_OVERLAP_CANCEL; |
| } |
| |
| static inline int is_overlap(struct dlm_lkb *lkb) |
| { |
| return (lkb->lkb_flags & (DLM_IFL_OVERLAP_UNLOCK | |
| DLM_IFL_OVERLAP_CANCEL)); |
| } |
| |
| static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv) |
| { |
| if (is_master_copy(lkb)) |
| return; |
| |
| del_timeout(lkb); |
| |
| DLM_ASSERT(lkb->lkb_lksb, dlm_print_lkb(lkb);); |
| |
| /* if the operation was a cancel, then return -DLM_ECANCEL, if a |
| timeout caused the cancel then return -ETIMEDOUT */ |
| if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_TIMEOUT_CANCEL)) { |
| lkb->lkb_flags &= ~DLM_IFL_TIMEOUT_CANCEL; |
| rv = -ETIMEDOUT; |
| } |
| |
| if (rv == -DLM_ECANCEL && (lkb->lkb_flags & DLM_IFL_DEADLOCK_CANCEL)) { |
| lkb->lkb_flags &= ~DLM_IFL_DEADLOCK_CANCEL; |
| rv = -EDEADLK; |
| } |
| |
| lkb->lkb_lksb->sb_status = rv; |
| lkb->lkb_lksb->sb_flags = lkb->lkb_sbflags; |
| |
| dlm_add_ast(lkb, AST_COMP); |
| } |
| |
| 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 { |
| lkb->lkb_bastmode = rqmode; |
| dlm_add_ast(lkb, AST_BAST); |
| } |
| } |
| |
| /* |
| * Basic operations on rsb's and lkb's |
| */ |
| |
| static struct dlm_rsb *create_rsb(struct dlm_ls *ls, char *name, int len) |
| { |
| struct dlm_rsb *r; |
| |
| r = dlm_allocate_rsb(ls, len); |
| if (!r) |
| return NULL; |
| |
| r->res_ls = ls; |
| r->res_length = len; |
| memcpy(r->res_name, name, len); |
| mutex_init(&r->res_mutex); |
| |
| INIT_LIST_HEAD(&r->res_lookup); |
| INIT_LIST_HEAD(&r->res_grantqueue); |
| INIT_LIST_HEAD(&r->res_convertqueue); |
| INIT_LIST_HEAD(&r->res_waitqueue); |
| INIT_LIST_HEAD(&r->res_root_list); |
| INIT_LIST_HEAD(&r->res_recover_list); |
| |
| return r; |
| } |
| |
| static int search_rsb_list(struct list_head *head, char *name, int len, |
| unsigned int flags, struct dlm_rsb **r_ret) |
| { |
| struct dlm_rsb *r; |
| int error = 0; |
| |
| list_for_each_entry(r, head, res_hashchain) { |
| if (len == r->res_length && !memcmp(name, r->res_name, len)) |
| goto found; |
| } |
| return -EBADR; |
| |
| found: |
| if (r->res_nodeid && (flags & R_MASTER)) |
| error = -ENOTBLK; |
| *r_ret = r; |
| return error; |
| } |
| |
| static int _search_rsb(struct dlm_ls *ls, char *name, int len, int b, |
| unsigned int flags, struct dlm_rsb **r_ret) |
| { |
| struct dlm_rsb *r; |
| int error; |
| |
| error = search_rsb_list(&ls->ls_rsbtbl[b].list, name, len, flags, &r); |
| if (!error) { |
| kref_get(&r->res_ref); |
| goto out; |
| } |
| error = search_rsb_list(&ls->ls_rsbtbl[b].toss, name, len, flags, &r); |
| if (error) |
| goto out; |
| |
| list_move(&r->res_hashchain, &ls->ls_rsbtbl[b].list); |
| |
| if (dlm_no_directory(ls)) |
| goto out; |
| |
| if (r->res_nodeid == -1) { |
| rsb_clear_flag(r, RSB_MASTER_UNCERTAIN); |
| r->res_first_lkid = 0; |
| } else if (r->res_nodeid > 0) { |
| rsb_set_flag(r, RSB_MASTER_UNCERTAIN); |
| r->res_first_lkid = 0; |
| } else { |
| DLM_ASSERT(r->res_nodeid == 0, dlm_print_rsb(r);); |
| DLM_ASSERT(!rsb_flag(r, RSB_MASTER_UNCERTAIN),); |
| } |
| out: |
| *r_ret = r; |
| return error; |
| } |
| |
| static int search_rsb(struct dlm_ls *ls, char *name, int len, int b, |
| unsigned int flags, struct dlm_rsb **r_ret) |
| { |
| int error; |
| write_lock(&ls->ls_rsbtbl[b].lock); |
| error = _search_rsb(ls, name, len, b, flags, r_ret); |
| write_unlock(&ls->ls_rsbtbl[b].lock); |
| return error; |
| } |
| |
| /* |
| * 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. |
| */ |
| |
| static int find_rsb(struct dlm_ls *ls, char *name, int namelen, |
| unsigned int flags, struct dlm_rsb **r_ret) |
| { |
| struct dlm_rsb *r, *tmp; |
| uint32_t hash, bucket; |
| int error = -EINVAL; |
| |
| if (namelen > DLM_RESNAME_MAXLEN) |
| goto out; |
| |
| if (dlm_no_directory(ls)) |
| flags |= R_CREATE; |
| |
| error = 0; |
| hash = jhash(name, namelen, 0); |
| bucket = hash & (ls->ls_rsbtbl_size - 1); |
| |
| error = search_rsb(ls, name, namelen, bucket, flags, &r); |
| if (!error) |
| goto out; |
| |
| if (error == -EBADR && !(flags & R_CREATE)) |
| goto out; |
| |
| /* the rsb was found but wasn't a master copy */ |
| if (error == -ENOTBLK) |
| goto out; |
| |
| error = -ENOMEM; |
| r = create_rsb(ls, name, namelen); |
| if (!r) |
| goto out; |
| |
| r->res_hash = hash; |
| r->res_bucket = bucket; |
| r->res_nodeid = -1; |
| kref_init(&r->res_ref); |
| |
| /* With no directory, the master can be set immediately */ |
| if (dlm_no_directory(ls)) { |
| int nodeid = dlm_dir_nodeid(r); |
| if (nodeid == dlm_our_nodeid()) |
| nodeid = 0; |
| r->res_nodeid = nodeid; |
| } |
| |
| write_lock(&ls->ls_rsbtbl[bucket].lock); |
| error = _search_rsb(ls, name, namelen, bucket, 0, &tmp); |
| if (!error) { |
| write_unlock(&ls->ls_rsbtbl[bucket].lock); |
| dlm_free_rsb(r); |
| r = tmp; |
| goto out; |
| } |
| list_add(&r->res_hashchain, &ls->ls_rsbtbl[bucket].list); |
| write_unlock(&ls->ls_rsbtbl[bucket].lock); |
| error = 0; |
| out: |
| *r_ret = r; |
| return error; |
| } |
| |
| /* This is only called to add a reference when the code already holds |
| a valid reference to the rsb, so there's no need for locking. */ |
| |
| static inline void hold_rsb(struct dlm_rsb *r) |
| { |
| kref_get(&r->res_ref); |
| } |
| |
| void dlm_hold_rsb(struct dlm_rsb *r) |
| { |
| hold_rsb(r); |
| } |
| |
| static void toss_rsb(struct kref *kref) |
| { |
| struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref); |
| struct dlm_ls *ls = r->res_ls; |
| |
| DLM_ASSERT(list_empty(&r->res_root_list), dlm_print_rsb(r);); |
| kref_init(&r->res_ref); |
| list_move(&r->res_hashchain, &ls->ls_rsbtbl[r->res_bucket].toss); |
| r->res_toss_time = jiffies; |
| if (r->res_lvbptr) { |
| dlm_free_lvb(r->res_lvbptr); |
| r->res_lvbptr = NULL; |
| } |
| } |
| |
| /* When all references to the rsb are gone it's transfered to |
| the tossed list for later disposal. */ |
| |
| static void put_rsb(struct dlm_rsb *r) |
| { |
| struct dlm_ls *ls = r->res_ls; |
| uint32_t bucket = r->res_bucket; |
| |
| write_lock(&ls->ls_rsbtbl[bucket].lock); |
| kref_put(&r->res_ref, toss_rsb); |
| write_unlock(&ls->ls_rsbtbl[bucket].lock); |
| } |
| |
| void dlm_put_rsb(struct dlm_rsb *r) |
| { |
| put_rsb(r); |
| } |
| |
| /* See comment for unhold_lkb */ |
| |
| static void unhold_rsb(struct dlm_rsb *r) |
| { |
| int rv; |
| rv = kref_put(&r->res_ref, toss_rsb); |
| DLM_ASSERT(!rv, dlm_dump_rsb(r);); |
| } |
| |
| static void kill_rsb(struct kref *kref) |
| { |
| struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref); |
| |
| /* All work is done after the return from kref_put() so we |
| can release the write_lock before the remove and free. */ |
| |
| 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_recover_list), dlm_dump_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) |
| { |
| struct dlm_lkb *lkb, *tmp; |
| uint32_t lkid = 0; |
| uint16_t bucket; |
| |
| lkb = dlm_allocate_lkb(ls); |
| if (!lkb) |
| return -ENOMEM; |
| |
| 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); |
| INIT_LIST_HEAD(&lkb->lkb_time_list); |
| |
| get_random_bytes(&bucket, sizeof(bucket)); |
| bucket &= (ls->ls_lkbtbl_size - 1); |
| |
| write_lock(&ls->ls_lkbtbl[bucket].lock); |
| |
| /* counter can roll over so we must verify lkid is not in use */ |
| |
| while (lkid == 0) { |
| lkid = (bucket << 16) | ls->ls_lkbtbl[bucket].counter++; |
| |
| list_for_each_entry(tmp, &ls->ls_lkbtbl[bucket].list, |
| lkb_idtbl_list) { |
| if (tmp->lkb_id != lkid) |
| continue; |
| lkid = 0; |
| break; |
| } |
| } |
| |
| lkb->lkb_id = lkid; |
| list_add(&lkb->lkb_idtbl_list, &ls->ls_lkbtbl[bucket].list); |
| write_unlock(&ls->ls_lkbtbl[bucket].lock); |
| |
| *lkb_ret = lkb; |
| return 0; |
| } |
| |
| static struct dlm_lkb *__find_lkb(struct dlm_ls *ls, uint32_t lkid) |
| { |
| struct dlm_lkb *lkb; |
| uint16_t bucket = (lkid >> 16); |
| |
| list_for_each_entry(lkb, &ls->ls_lkbtbl[bucket].list, lkb_idtbl_list) { |
| if (lkb->lkb_id == lkid) |
| return lkb; |
| } |
| return NULL; |
| } |
| |
| static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret) |
| { |
| struct dlm_lkb *lkb; |
| uint16_t bucket = (lkid >> 16); |
| |
| if (bucket >= ls->ls_lkbtbl_size) |
| return -EBADSLT; |
| |
| read_lock(&ls->ls_lkbtbl[bucket].lock); |
| lkb = __find_lkb(ls, lkid); |
| if (lkb) |
| kref_get(&lkb->lkb_ref); |
| read_unlock(&ls->ls_lkbtbl[bucket].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) |
| { |
| uint16_t bucket = (lkb->lkb_id >> 16); |
| |
| write_lock(&ls->ls_lkbtbl[bucket].lock); |
| if (kref_put(&lkb->lkb_ref, kill_lkb)) { |
| list_del(&lkb->lkb_idtbl_list); |
| write_unlock(&ls->ls_lkbtbl[bucket].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 1; |
| } else { |
| write_unlock(&ls->ls_lkbtbl[bucket].lock); |
| return 0; |
| } |
| } |
| |
| 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); |
| } |
| |
| /* 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) |
| { |
| int rv; |
| rv = kref_put(&lkb->lkb_ref, kill_lkb); |
| DLM_ASSERT(!rv, dlm_print_lkb(lkb);); |
| } |
| |
| static void lkb_add_ordered(struct list_head *new, struct list_head *head, |
| int mode) |
| { |
| struct dlm_lkb *lkb = NULL; |
| |
| list_for_each_entry(lkb, head, lkb_statequeue) |
| if (lkb->lkb_rqmode < mode) |
| break; |
| |
| if (!lkb) |
| list_add_tail(new, head); |
| else |
| __list_add(new, lkb->lkb_statequeue.prev, &lkb->lkb_statequeue); |
| } |
| |
| /* 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_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) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int error = 0; |
| |
| mutex_lock(&ls->ls_waiters_mutex); |
| |
| 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: |
| lkb->lkb_flags |= DLM_IFL_OVERLAP_UNLOCK; |
| break; |
| case DLM_MSG_CANCEL: |
| lkb->lkb_flags |= DLM_IFL_OVERLAP_CANCEL; |
| break; |
| default: |
| error = -EBUSY; |
| goto out; |
| } |
| lkb->lkb_wait_count++; |
| hold_lkb(lkb); |
| |
| log_debug(ls, "add overlap %x cur %d new %d count %d flags %x", |
| lkb->lkb_id, lkb->lkb_wait_type, mstype, |
| lkb->lkb_wait_count, lkb->lkb_flags); |
| 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; |
| hold_lkb(lkb); |
| list_add(&lkb->lkb_wait_reply, &ls->ls_waiters); |
| out: |
| if (error) |
| log_error(ls, "add_to_waiters %x error %d flags %x %d %d %s", |
| lkb->lkb_id, error, lkb->lkb_flags, mstype, |
| lkb->lkb_wait_type, lkb->lkb_resource->res_name); |
| mutex_unlock(&ls->ls_waiters_mutex); |
| 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) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int overlap_done = 0; |
| |
| if (is_overlap_unlock(lkb) && (mstype == DLM_MSG_UNLOCK_REPLY)) { |
| lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK; |
| overlap_done = 1; |
| goto out_del; |
| } |
| |
| if (is_overlap_cancel(lkb) && (mstype == DLM_MSG_CANCEL_REPLY)) { |
| lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL; |
| overlap_done = 1; |
| 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, "remove_from_waiters lkid %x flags %x types %d %d", |
| lkb->lkb_id, lkb->lkb_flags, mstype, lkb->lkb_wait_type); |
| 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, "remove_from_waiters %x reply %d give up on %d", |
| lkb->lkb_id, mstype, lkb->lkb_wait_type); |
| lkb->lkb_wait_count--; |
| lkb->lkb_wait_type = 0; |
| } |
| |
| DLM_ASSERT(lkb->lkb_wait_count, dlm_print_lkb(lkb);); |
| |
| lkb->lkb_flags &= ~DLM_IFL_RESEND; |
| 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; |
| |
| mutex_lock(&ls->ls_waiters_mutex); |
| error = _remove_from_waiters(lkb, mstype); |
| mutex_unlock(&ls->ls_waiters_mutex); |
| return error; |
| } |
| |
| /* Handles situations where we might be processing a "fake" or "stub" reply in |
| which we can't try to take waiters_mutex again. */ |
| |
| static int remove_from_waiters_ms(struct dlm_lkb *lkb, struct dlm_message *ms) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| int error; |
| |
| if (ms != &ls->ls_stub_ms) |
| mutex_lock(&ls->ls_waiters_mutex); |
| error = _remove_from_waiters(lkb, ms->m_type); |
| if (ms != &ls->ls_stub_ms) |
| mutex_unlock(&ls->ls_waiters_mutex); |
| return error; |
| } |
| |
| static void dir_remove(struct dlm_rsb *r) |
| { |
| int to_nodeid; |
| |
| if (dlm_no_directory(r->res_ls)) |
| return; |
| |
| to_nodeid = dlm_dir_nodeid(r); |
| if (to_nodeid != dlm_our_nodeid()) |
| send_remove(r); |
| else |
| dlm_dir_remove_entry(r->res_ls, to_nodeid, |
| r->res_name, r->res_length); |
| } |
| |
| /* FIXME: shouldn't this be able to exit as soon as one non-due rsb is |
| found since they are in order of newest to oldest? */ |
| |
| static int shrink_bucket(struct dlm_ls *ls, int b) |
| { |
| struct dlm_rsb *r; |
| int count = 0, found; |
| |
| for (;;) { |
| found = 0; |
| write_lock(&ls->ls_rsbtbl[b].lock); |
| list_for_each_entry_reverse(r, &ls->ls_rsbtbl[b].toss, |
| res_hashchain) { |
| if (!time_after_eq(jiffies, r->res_toss_time + |
| dlm_config.ci_toss_secs * HZ)) |
| continue; |
| found = 1; |
| break; |
| } |
| |
| if (!found) { |
| write_unlock(&ls->ls_rsbtbl[b].lock); |
| break; |
| } |
| |
| if (kref_put(&r->res_ref, kill_rsb)) { |
| list_del(&r->res_hashchain); |
| write_unlock(&ls->ls_rsbtbl[b].lock); |
| |
| if (is_master(r)) |
| dir_remove(r); |
| dlm_free_rsb(r); |
| count++; |
| } else { |
| write_unlock(&ls->ls_rsbtbl[b].lock); |
| log_error(ls, "tossed rsb in use %s", r->res_name); |
| } |
| } |
| |
| return count; |
| } |
| |
| void dlm_scan_rsbs(struct dlm_ls *ls) |
| { |
| int i; |
| |
| for (i = 0; i < ls->ls_rsbtbl_size; i++) { |
| shrink_bucket(ls, i); |
| if (dlm_locking_stopped(ls)) |
| break; |
| cond_resched(); |
| } |
| } |
| |
| static void add_timeout(struct dlm_lkb *lkb) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| |
| if (is_master_copy(lkb)) { |
| lkb->lkb_timestamp = jiffies; |
| return; |
| } |
| |
| if (test_bit(LSFL_TIMEWARN, &ls->ls_flags) && |
| !(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) { |
| lkb->lkb_flags |= DLM_IFL_WATCH_TIMEWARN; |
| goto add_it; |
| } |
| if (lkb->lkb_exflags & DLM_LKF_TIMEOUT) |
| goto add_it; |
| return; |
| |
| add_it: |
| DLM_ASSERT(list_empty(&lkb->lkb_time_list), dlm_print_lkb(lkb);); |
| mutex_lock(&ls->ls_timeout_mutex); |
| hold_lkb(lkb); |
| lkb->lkb_timestamp = jiffies; |
| list_add_tail(&lkb->lkb_time_list, &ls->ls_timeout); |
| mutex_unlock(&ls->ls_timeout_mutex); |
| } |
| |
| static void del_timeout(struct dlm_lkb *lkb) |
| { |
| struct dlm_ls *ls = lkb->lkb_resource->res_ls; |
| |
| mutex_lock(&ls->ls_timeout_mutex); |
| if (!list_empty(&lkb->lkb_time_list)) { |
| list_del_init(&lkb->lkb_time_list); |
| unhold_lkb(lkb); |
| } |
| mutex_unlock(&ls->ls_timeout_mutex); |
| } |
| |
| /* FIXME: is it safe to look at lkb_exflags, lkb_flags, lkb_timestamp, and |
| lkb_lksb_timeout without lock_rsb? Note: we can't lock timeout_mutex |
| and then lock rsb because of lock ordering in add_timeout. We may need |
| to specify some special timeout-related bits in the lkb that are just to |
| be accessed under the timeout_mutex. */ |
| |
| void dlm_scan_timeout(struct dlm_ls *ls) |
| { |
| struct dlm_rsb *r; |
| struct dlm_lkb *lkb; |
| int do_cancel, do_warn; |
| |
| for (;;) { |
| if (dlm_locking_stopped(ls)) |
| break; |
| |
| do_cancel = 0; |
| do_warn = 0; |
| mutex_lock(&ls->ls_timeout_mutex); |
| list_for_each_entry(lkb, &ls->ls_timeout, lkb_time_list) { |
| |
| if ((lkb->lkb_exflags & DLM_LKF_TIMEOUT) && |
| time_after_eq(jiffies, lkb->lkb_timestamp + |
| lkb->lkb_timeout_cs * HZ/100)) |
| do_cancel = 1; |
| |
| if ((lkb->lkb_flags & DLM_IFL_WATCH_TIMEWARN) && |
| time_after_eq(jiffies, lkb->lkb_timestamp + |
| dlm_config.ci_timewarn_cs * HZ/100)) |
| do_warn = 1; |
| |
| if (!do_cancel && !do_warn) |
| continue; |
| hold_lkb(lkb); |
| break; |
| } |
| mutex_unlock(&ls->ls_timeout_mutex); |
| |
| if (!do_cancel && !do_warn) |
| break; |
| |
| r = lkb->lkb_resource; |
| hold_rsb(r); |
| lock_rsb(r); |
| |
| if (do_warn) { |
| /* clear flag so we only warn once */ |
| lkb->lkb_flags &= ~DLM_IFL_WATCH_TIMEWARN; |
| if (!(lkb->lkb_exflags & DLM_LKF_TIMEOUT)) |
| del_timeout(lkb); |
| dlm_timeout_warn(lkb); |
| } |
| |
| if (do_cancel) { |
| log_debug(ls, "timeout cancel %x node %d %s", |
| lkb->lkb_id, lkb->lkb_nodeid, r->res_name); |
| lkb->lkb_flags &= ~DLM_IFL_WATCH_TIMEWARN; |
| lkb->lkb_flags |= DLM_IFL_TIMEOUT_CANCEL; |
| del_timeout(lkb); |
| _cancel_lock(r, lkb); |
| } |
| |
| unlock_rsb(r); |
| unhold_rsb(r); |
| dlm_put_lkb(lkb); |
| } |
| } |
| |
| /* This is only called by dlm_recoverd, and we rely on dlm_ls_stop() stopping |
| dlm_recoverd before checking/setting ls_recover_begin. */ |
| |
| void dlm_adjust_timeouts(struct dlm_ls *ls) |
| { |
| struct dlm_lkb *lkb; |
| long adj = jiffies - ls->ls_recover_begin; |
| |
| ls->ls_recover_begin = 0; |
| mutex_lock(&ls->ls_timeout_mutex); |
| list_for_each_entry(lkb, &ls->ls_timeout, lkb_time_list) |
| lkb->lkb_timestamp += adj; |
| mutex_unlock(&ls->ls_timeout_mutex); |
| } |
| |
| /* 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)) |
| lkb->lkb_sbflags |= DLM_SBF_VALNOTVALID; |
| } |
| |
| 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, |
| 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 > DLM_RESNAME_MAXLEN) |
| len = DLM_RESNAME_MAXLEN; |
| memcpy(lkb->lkb_lvbptr, ms->m_extra, len); |
| lkb->lkb_lvbseq = 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; |
| } |
| |
| static void grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| set_lvb_lock(r, lkb); |
| _grant_lock(r, lkb); |
| lkb->lkb_highbast = 0; |
| } |
| |
| static void grant_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| 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, struct dlm_message *ms) |
| { |
| if (ms->m_type != DLM_MSG_CONVERT_REPLY) { |
| log_print("munge_demoted %x invalid reply type %d", |
| lkb->lkb_id, ms->m_type); |
| return; |
| } |
| |
| 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, struct dlm_message *ms) |
| { |
| if (ms->m_type != DLM_MSG_REQUEST_REPLY && |
| ms->m_type != DLM_MSG_GRANT) { |
| log_print("munge_altmode %x invalid reply type %d", |
| lkb->lkb_id, 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. |
| * |
| * 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) |
| { |
| 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)) |
| goto out; |
| |
| /* |
| * 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)) |
| goto out; |
| |
| /* |
| * 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; |
| |
| /* |
| * 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; |
| out: |
| return 0; |
| } |
| |
| static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now, |
| 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); |
| 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; |
| lkb->lkb_sbflags |= DLM_SBF_DEMOTED; |
| } else if (!(lkb->lkb_exflags & DLM_LKF_NODLCKWT)) { |
| 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); |
| if (rv) |
| lkb->lkb_sbflags |= DLM_SBF_ALTMODE; |
| else |
| lkb->lkb_rqmode = rqmode; |
| } |
| out: |
| return rv; |
| } |
| |
| /* FIXME: I don't think that can_be_granted() can/will demote or find deadlock |
| for locks pending on the convert list. Once verified (watch for these |
| log_prints), we should be able to just call _can_be_granted() and not |
| bother with the demote/deadlk cases here (and there's no easy way to deal |
| with a deadlk here, we'd have to generate something like grant_lock with |
| the deadlk error.) */ |
| |
| /* 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) |
| { |
| struct dlm_lkb *lkb, *s; |
| 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, &deadlk)) { |
| grant_lock_pending(r, lkb); |
| grant_restart = 1; |
| 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) { |
| 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) |
| { |
| struct dlm_lkb *lkb, *s; |
| |
| list_for_each_entry_safe(lkb, s, &r->res_waitqueue, lkb_statequeue) { |
| if (can_be_granted(r, lkb, 0, NULL)) |
| grant_lock_pending(r, lkb); |
| 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) |
| { |
| struct dlm_lkb *lkb, *s; |
| int high = DLM_LOCK_IV; |
| int cw = 0; |
| |
| DLM_ASSERT(is_master(r), dlm_dump_rsb(r);); |
| |
| high = grant_pending_convert(r, high, &cw); |
| high = grant_pending_wait(r, high, &cw); |
| |
| 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) |
| 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) { |
| 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) |
| { |
| struct dlm_ls *ls = r->res_ls; |
| int i, error, dir_nodeid, ret_nodeid, 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_nodeid == 0) { |
| lkb->lkb_nodeid = 0; |
| return 0; |
| } |
| |
| if (r->res_nodeid > 0) { |
| lkb->lkb_nodeid = r->res_nodeid; |
| return 0; |
| } |
| |
| DLM_ASSERT(r->res_nodeid == -1, dlm_dump_rsb(r);); |
| |
| dir_nodeid = dlm_dir_nodeid(r); |
| |
| if (dir_nodeid != our_nodeid) { |
| r->res_first_lkid = lkb->lkb_id; |
| send_lookup(r, lkb); |
| return 1; |
| } |
| |
| for (i = 0; i < 2; i++) { |
| /* It's possible for dlm_scand to remove an old rsb for |
| this same resource from the toss list, us to create |
| a new one, look up the master locally, and find it |
| already exists just before dlm_scand does the |
| dir_remove() on the previous rsb. */ |
| |
| error = dlm_dir_lookup(ls, our_nodeid, r->res_name, |
| r->res_length, &ret_nodeid); |
| if (!error) |
| break; |
| log_debug(ls, "dir_lookup error %d %s", error, r->res_name); |
| schedule(); |
| } |
| if (error && error != -EEXIST) |
| return error; |
| |
| if (ret_nodeid == our_nodeid) { |
| r->res_first_lkid = 0; |
| r->res_nodeid = 0; |
| lkb->lkb_nodeid = 0; |
| } else { |
| r->res_first_lkid = lkb->lkb_id; |
| r->res_nodeid = ret_nodeid; |
| lkb->lkb_nodeid = ret_nodeid; |
| } |
| return 0; |
| } |
| |
| 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); |
| schedule(); |
| } |
| } |
| |
| /* 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); |
| } else |
| r->res_nodeid = -1; |
| 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, unsigned long timeout_cs, |
| 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->timeout = timeout_cs; |
| 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 = -EINVAL; |
| |
| if (args->flags & DLM_LKF_CONVERT) { |
| if (lkb->lkb_flags & DLM_IFL_MSTCPY) |
| goto out; |
| |
| if (args->flags & DLM_LKF_QUECVT && |
| !__quecvt_compat_matrix[lkb->lkb_grmode+1][args->mode+1]) |
| goto out; |
| |
| rv = -EBUSY; |
| if (lkb->lkb_status != DLM_LKSTS_GRANTED) |
| goto out; |
| |
| if (lkb->lkb_wait_type) |
| goto out; |
| |
| if (is_overlap(lkb)) |
| goto out; |
| } |
| |
| lkb->lkb_exflags = args->flags; |
| lkb->lkb_sbflags = 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; |
| lkb->lkb_timeout_cs = args->timeout; |
| rv = 0; |
| out: |
| 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 = -EINVAL; |
| |
| if (lkb->lkb_flags & DLM_IFL_MSTCPY) { |
| 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 (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) { |
| log_debug(ls, "unlock on ENDOFLIFE %x", lkb->lkb_id); |
| rv = -ENOENT; |
| 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 */ |
| rv = -EBUSY; |
| 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; |
| |
| /* don't let scand try to do a cancel */ |
| del_timeout(lkb); |
| |
| if (lkb->lkb_flags & DLM_IFL_RESEND) { |
| lkb->lkb_flags |= DLM_IFL_OVERLAP_CANCEL; |
| rv = -EBUSY; |
| goto out; |
| } |
| |
| switch (lkb->lkb_wait_type) { |
| case DLM_MSG_LOOKUP: |
| case DLM_MSG_REQUEST: |
| lkb->lkb_flags |= DLM_IFL_OVERLAP_CANCEL; |
| 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; |
| |
| /* don't let scand try to do a cancel */ |
| del_timeout(lkb); |
| |
| if (lkb->lkb_flags & DLM_IFL_RESEND) { |
| lkb->lkb_flags |= DLM_IFL_OVERLAP_UNLOCK; |
| rv = -EBUSY; |
| goto out; |
| } |
| |
| switch (lkb->lkb_wait_type) { |
| case DLM_MSG_LOOKUP: |
| case DLM_MSG_REQUEST: |
| lkb->lkb_flags |= DLM_IFL_OVERLAP_UNLOCK; |
| rv = -EBUSY; |
| goto out; |
| case DLM_MSG_UNLOCK: |
| goto out; |
| } |
| /* add_to_waiters() will set OVERLAP_UNLOCK */ |
| goto out_ok; |
| } |
| |
| /* normal unlock not allowed if there's any op in progress */ |
| rv = -EBUSY; |
| if (lkb->lkb_wait_type || lkb->lkb_wait_count) |
| goto out; |
| |
| out_ok: |
| /* an overlapping op shouldn't blow away exflags from other op */ |
| lkb->lkb_exflags |= args->flags; |
| lkb->lkb_sbflags = 0; |
| lkb->lkb_astparam = args->astparam; |
| rv = 0; |
| out: |
| if (rv) |
| log_debug(ls, "validate_unlock_args %d %x %x %x %x %d %s", rv, |
| lkb->lkb_id, lkb->lkb_flags, lkb->lkb_exflags, |
| args->flags, lkb->lkb_wait_type, |
| lkb->lkb_resource->res_name); |
| 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, 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); |
| send_blocking_asts(r, lkb); |
| add_timeout(lkb); |
| goto out; |
| } |
| |
| error = -EAGAIN; |
| if (force_blocking_asts(lkb)) |
| send_blocking_asts_all(r, lkb); |
| queue_cast(r, lkb, -EAGAIN); |
| |
| out: |
| return error; |
| } |
| |
| 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, &deadlk)) { |
| grant_lock(r, lkb); |
| queue_cast(r, lkb, 0); |
| grant_pending_locks(r); |
| 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) { |
| /* it's left on the granted queue */ |
| log_debug(r->res_ls, "deadlock %x node %d sts%d g%d r%d %s", |
| lkb->lkb_id, lkb->lkb_nodeid, lkb->lkb_status, |
| lkb->lkb_grmode, lkb->lkb_rqmode, r->res_name); |
| 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); |
| if (_can_be_granted(r, lkb, 1)) { |
| grant_lock(r, lkb); |
| queue_cast(r, lkb, 0); |
| grant_pending_locks(r); |
| 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); |
| send_blocking_asts(r, lkb); |
| add_timeout(lkb); |
| goto out; |
| } |
| |
| error = -EAGAIN; |
| if (force_blocking_asts(lkb)) |
| send_blocking_asts_all(r, lkb); |
| queue_cast(r, lkb, -EAGAIN); |
| |
| out: |
| return error; |
| } |
| |
| static int do_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| remove_lock(r, lkb); |
| queue_cast(r, lkb, -DLM_EUNLOCK); |
| grant_pending_locks(r); |
| return -DLM_EUNLOCK; |
| } |
| |
| /* returns: 0 did nothing, -DLM_ECANCEL canceled lock */ |
| |
| static int do_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error; |
| |
| error = revert_lock(r, lkb); |
| if (error) { |
| queue_cast(r, lkb, -DLM_ECANCEL); |
| grant_pending_locks(r); |
| return -DLM_ECANCEL; |
| } |
| return 0; |
| } |
| |
| /* |
| * Four stage 3 varieties: |
| * _request_lock(), _convert_lock(), _unlock_lock(), _cancel_lock() |
| */ |
| |
| /* add a new lkb to a possibly new rsb, called by requesting process */ |
| |
| static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error; |
| |
| /* set_master: sets lkb nodeid from r */ |
| |
| error = set_master(r, lkb); |
| if (error < 0) |
| goto out; |
| if (error) { |
| error = 0; |
| goto out; |
| } |
| |
| if (is_remote(r)) |
| /* receive_request() calls do_request() on remote node */ |
| error = send_request(r, lkb); |
| else |
| error = do_request(r, lkb); |
| out: |
| return error; |
| } |
| |
| /* change some property of an existing lkb, e.g. mode */ |
| |
| static int _convert_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error; |
| |
| if (is_remote(r)) |
| /* receive_convert() calls do_convert() on remote node */ |
| error = send_convert(r, lkb); |
| else |
| error = do_convert(r, lkb); |
| |
| return error; |
| } |
| |
| /* remove an existing lkb from the granted queue */ |
| |
| static int _unlock_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error; |
| |
| if (is_remote(r)) |
| /* receive_unlock() calls do_unlock() on remote node */ |
| error = send_unlock(r, lkb); |
| else |
| error = do_unlock(r, lkb); |
| |
| return error; |
| } |
| |
| /* remove an existing lkb from the convert or wait queue */ |
| |
| static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error; |
| |
| if (is_remote(r)) |
| /* receive_cancel() calls do_cancel() on remote node */ |
| error = send_cancel(r, lkb); |
| else |
| error = do_cancel(r, lkb); |
| |
| return error; |
| } |
| |
| /* |
| * Four stage 2 varieties: |
| * request_lock(), convert_lock(), unlock_lock(), cancel_lock() |
| */ |
| |
| static int request_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, char *name, |
| int len, struct dlm_args *args) |
| { |
| struct dlm_rsb *r; |
| int error; |
| |
| error = validate_lock_args(ls, lkb, args); |
| if (error) |
| goto out; |
| |
| error = find_rsb(ls, name, len, R_CREATE, &r); |
| if (error) |
| goto out; |
| |
| lock_rsb(r); |
| |
| attach_lkb(r, lkb); |
| lkb->lkb_lksb->sb_lkid = lkb->lkb_id; |
| |
| error = _request_lock(r, lkb); |
| |
| unlock_rsb(r); |
| put_rsb(r); |
| |
| out: |
| return error; |
| } |
| |
| static int convert_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_args *args) |
| { |
| struct dlm_rsb *r; |
| int error; |
| |
| r = lkb->lkb_resource; |
| |
| hold_rsb(r); |
| lock_rsb(r); |
| |
| error = validate_lock_args(ls, lkb, args); |
| if (error) |
| goto out; |
| |
| error = _convert_lock(r, lkb); |
| out: |
| unlock_rsb(r); |
| put_rsb(r); |
| return error; |
| } |
| |
| static int unlock_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_args *args) |
| { |
| struct dlm_rsb *r; |
| int error; |
| |
| r = lkb->lkb_resource; |
| |
| hold_rsb(r); |
| lock_rsb(r); |
| |
| error = validate_unlock_args(lkb, args); |
| if (error) |
| goto out; |
| |
| error = _unlock_lock(r, lkb); |
| out: |
| unlock_rsb(r); |
| put_rsb(r); |
| return error; |
| } |
| |
| static int cancel_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_args *args) |
| { |
| struct dlm_rsb *r; |
| int error; |
| |
| r = lkb->lkb_resource; |
| |
| hold_rsb(r); |
| lock_rsb(r); |
| |
| error = validate_unlock_args(lkb, args); |
| if (error) |
| goto out; |
| |
| error = _cancel_lock(r, lkb); |
| out: |
| unlock_rsb(r); |
| put_rsb(r); |
| return error; |
| } |
| |
| /* |
| * Two stage 1 varieties: dlm_lock() and dlm_unlock() |
| */ |
| |
| int dlm_lock(dlm_lockspace_t *lockspace, |
| int mode, |
| struct dlm_lksb *lksb, |
| uint32_t flags, |
| void *name, |
| unsigned int namelen, |
| uint32_t parent_lkid, |
| void (*ast) (void *astarg), |
| void *astarg, |
| void (*bast) (void *astarg, int mode)) |
| { |
| struct dlm_ls *ls; |
| struct dlm_lkb *lkb; |
| struct dlm_args args; |
| int error, convert = flags & DLM_LKF_CONVERT; |
| |
| ls = dlm_find_lockspace_local(lockspace); |
| if (!ls) |
| return -EINVAL; |
| |
| dlm_lock_recovery(ls); |
| |
| if (convert) |
| error = find_lkb(ls, lksb->sb_lkid, &lkb); |
| else |
| error = create_lkb(ls, &lkb); |
| |
| if (error) |
| goto out; |
| |
| error = set_lock_args(mode, lksb, flags, namelen, 0, ast, |
| astarg, bast, &args); |
| if (error) |
| goto out_put; |
| |
| if (convert) |
| error = convert_lock(ls, lkb, &args); |
| else |
| error = request_lock(ls, lkb, name, namelen, &args); |
| |
| if (error == -EINPROGRESS) |
| error = 0; |
| out_put: |
| if (convert || error) |
| __put_lkb(ls, lkb); |
| if (error == -EAGAIN || error == -EDEADLK) |
| error = 0; |
| out: |
| dlm_unlock_recovery(ls); |
| dlm_put_lockspace(ls); |
| return error; |
| } |
| |
| int dlm_unlock(dlm_lockspace_t *lockspace, |
| uint32_t lkid, |
| uint32_t flags, |
| struct dlm_lksb *lksb, |
| void *astarg) |
| { |
| struct dlm_ls *ls; |
| struct dlm_lkb *lkb; |
| struct dlm_args args; |
| int error; |
| |
| ls = dlm_find_lockspace_local(lockspace); |
| if (!ls) |
| return -EINVAL; |
| |
| dlm_lock_recovery(ls); |
| |
| error = find_lkb(ls, lkid, &lkb); |
| if (error) |
| goto out; |
| |
| error = set_unlock_args(flags, astarg, &args); |
| if (error) |
| goto out_put; |
| |
| if (flags & DLM_LKF_CANCEL) |
| error = cancel_lock(ls, lkb, &args); |
| else |
| error = unlock_lock(ls, lkb, &args); |
| |
| if (error == -DLM_EUNLOCK || error == -DLM_ECANCEL) |
| error = 0; |
| if (error == -EBUSY && (flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK))) |
| error = 0; |
| out_put: |
| dlm_put_lkb(lkb); |
| out: |
| dlm_unlock_recovery(ls); |
| dlm_put_lockspace(ls); |
| return error; |
| } |
| |
| /* |
| * send/receive routines for remote operations and replies |
| * |
| * send_args |
| * send_common |
| * send_request receive_request |
| * send_convert receive_convert |
| * send_unlock receive_unlock |
| * send_cancel receive_cancel |
| * send_grant receive_grant |
| * send_bast receive_bast |
| * send_lookup receive_lookup |
| * send_remove receive_remove |
| * |
| * send_common_reply |
| * receive_request_reply send_request_reply |
| * receive_convert_reply send_convert_reply |
| * receive_unlock_reply send_unlock_reply |
| * receive_cancel_reply send_cancel_reply |
| * receive_lookup_reply send_lookup_reply |
| */ |
| |
| static int _create_message(struct dlm_ls *ls, int mb_len, |
| int to_nodeid, int mstype, |
| struct dlm_message **ms_ret, |
| struct dlm_mhandle **mh_ret) |
| { |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| char *mb; |
| |
| /* get_buffer gives us a message handle (mh) that we need to |
| pass into lowcomms_commit and a message buffer (mb) that we |
| write our data into */ |
| |
| mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, ls->ls_allocation, &mb); |
| if (!mh) |
| return -ENOBUFS; |
| |
| memset(mb, 0, mb_len); |
| |
| ms = (struct dlm_message *) mb; |
| |
| ms->m_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR); |
| ms->m_header.h_lockspace = ls->ls_global_id; |
| ms->m_header.h_nodeid = dlm_our_nodeid(); |
| ms->m_header.h_length = mb_len; |
| ms->m_header.h_cmd = DLM_MSG; |
| |
| ms->m_type = mstype; |
| |
| *mh_ret = mh; |
| *ms_ret = ms; |
| return 0; |
| } |
| |
| static int create_message(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| int to_nodeid, int mstype, |
| struct dlm_message **ms_ret, |
| struct dlm_mhandle **mh_ret) |
| { |
| int mb_len = sizeof(struct dlm_message); |
| |
| switch (mstype) { |
| case DLM_MSG_REQUEST: |
| case DLM_MSG_LOOKUP: |
| case DLM_MSG_REMOVE: |
| mb_len += r->res_length; |
| break; |
| case DLM_MSG_CONVERT: |
| case DLM_MSG_UNLOCK: |
| case DLM_MSG_REQUEST_REPLY: |
| case DLM_MSG_CONVERT_REPLY: |
| case DLM_MSG_GRANT: |
| if (lkb && lkb->lkb_lvbptr) |
| mb_len += r->res_ls->ls_lvblen; |
| break; |
| } |
| |
| return _create_message(r->res_ls, mb_len, to_nodeid, mstype, |
| ms_ret, mh_ret); |
| } |
| |
| /* further lowcomms enhancements or alternate implementations may make |
| the return value from this function useful at some point */ |
| |
| static int send_message(struct dlm_mhandle *mh, struct dlm_message *ms) |
| { |
| dlm_message_out(ms); |
| dlm_lowcomms_commit_buffer(mh); |
| return 0; |
| } |
| |
| static void send_args(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| struct dlm_message *ms) |
| { |
| ms->m_nodeid = lkb->lkb_nodeid; |
| ms->m_pid = lkb->lkb_ownpid; |
| ms->m_lkid = lkb->lkb_id; |
| ms->m_remid = lkb->lkb_remid; |
| ms->m_exflags = lkb->lkb_exflags; |
| ms->m_sbflags = lkb->lkb_sbflags; |
| ms->m_flags = lkb->lkb_flags; |
| ms->m_lvbseq = lkb->lkb_lvbseq; |
| ms->m_status = lkb->lkb_status; |
| ms->m_grmode = lkb->lkb_grmode; |
| ms->m_rqmode = lkb->lkb_rqmode; |
| ms->m_hash = r->res_hash; |
| |
| /* m_result and m_bastmode are set from function args, |
| not from lkb fields */ |
| |
| if (lkb->lkb_bastfn) |
| ms->m_asts |= AST_BAST; |
| if (lkb->lkb_astfn) |
| ms->m_asts |= AST_COMP; |
| |
| /* compare with switch in create_message; send_remove() doesn't |
| use send_args() */ |
| |
| switch (ms->m_type) { |
| case DLM_MSG_REQUEST: |
| case DLM_MSG_LOOKUP: |
| memcpy(ms->m_extra, r->res_name, r->res_length); |
| break; |
| case DLM_MSG_CONVERT: |
| case DLM_MSG_UNLOCK: |
| case DLM_MSG_REQUEST_REPLY: |
| case DLM_MSG_CONVERT_REPLY: |
| case DLM_MSG_GRANT: |
| if (!lkb->lkb_lvbptr) |
| break; |
| memcpy(ms->m_extra, lkb->lkb_lvbptr, r->res_ls->ls_lvblen); |
| break; |
| } |
| } |
| |
| static int send_common(struct dlm_rsb *r, struct dlm_lkb *lkb, int mstype) |
| { |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| int to_nodeid, error; |
| |
| error = add_to_waiters(lkb, mstype); |
| if (error) |
| return error; |
| |
| to_nodeid = r->res_nodeid; |
| |
| error = create_message(r, lkb, to_nodeid, mstype, &ms, &mh); |
| if (error) |
| goto fail; |
| |
| send_args(r, lkb, ms); |
| |
| error = send_message(mh, ms); |
| if (error) |
| goto fail; |
| return 0; |
| |
| fail: |
| remove_from_waiters(lkb, msg_reply_type(mstype)); |
| return error; |
| } |
| |
| static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| return send_common(r, lkb, DLM_MSG_REQUEST); |
| } |
| |
| static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| int error; |
| |
| error = send_common(r, lkb, DLM_MSG_CONVERT); |
| |
| /* down conversions go without a reply from the master */ |
| if (!error && down_conversion(lkb)) { |
| remove_from_waiters(lkb, DLM_MSG_CONVERT_REPLY); |
| r->res_ls->ls_stub_ms.m_type = DLM_MSG_CONVERT_REPLY; |
| r->res_ls->ls_stub_ms.m_result = 0; |
| r->res_ls->ls_stub_ms.m_flags = lkb->lkb_flags; |
| __receive_convert_reply(r, lkb, &r->res_ls->ls_stub_ms); |
| } |
| |
| return error; |
| } |
| |
| /* FIXME: if this lkb is the only lock we hold on the rsb, then set |
| MASTER_UNCERTAIN to force the next request on the rsb to confirm |
| that the master is still correct. */ |
| |
| static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| return send_common(r, lkb, DLM_MSG_UNLOCK); |
| } |
| |
| static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| return send_common(r, lkb, DLM_MSG_CANCEL); |
| } |
| |
| static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| int to_nodeid, error; |
| |
| to_nodeid = lkb->lkb_nodeid; |
| |
| error = create_message(r, lkb, to_nodeid, DLM_MSG_GRANT, &ms, &mh); |
| if (error) |
| goto out; |
| |
| send_args(r, lkb, ms); |
| |
| ms->m_result = 0; |
| |
| error = send_message(mh, ms); |
| out: |
| return error; |
| } |
| |
| static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode) |
| { |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| int to_nodeid, error; |
| |
| to_nodeid = lkb->lkb_nodeid; |
| |
| error = create_message(r, NULL, to_nodeid, DLM_MSG_BAST, &ms, &mh); |
| if (error) |
| goto out; |
| |
| send_args(r, lkb, ms); |
| |
| ms->m_bastmode = mode; |
| |
| error = send_message(mh, ms); |
| out: |
| return error; |
| } |
| |
| static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb) |
| { |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| int to_nodeid, error; |
| |
| error = add_to_waiters(lkb, DLM_MSG_LOOKUP); |
| if (error) |
| return error; |
| |
| to_nodeid = dlm_dir_nodeid(r); |
| |
| error = create_message(r, NULL, to_nodeid, DLM_MSG_LOOKUP, &ms, &mh); |
| if (error) |
| goto fail; |
| |
| send_args(r, lkb, ms); |
| |
| error = send_message(mh, ms); |
| if (error) |
| goto fail; |
| return 0; |
| |
| fail: |
| remove_from_waiters(lkb, DLM_MSG_LOOKUP_REPLY); |
| return error; |
| } |
| |
| static int send_remove(struct dlm_rsb *r) |
| { |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| int to_nodeid, error; |
| |
| to_nodeid = dlm_dir_nodeid(r); |
| |
| error = create_message(r, NULL, to_nodeid, DLM_MSG_REMOVE, &ms, &mh); |
| if (error) |
| goto out; |
| |
| memcpy(ms->m_extra, r->res_name, r->res_length); |
| ms->m_hash = r->res_hash; |
| |
| error = send_message(mh, ms); |
| out: |
| return error; |
| } |
| |
| static int send_common_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, |
| int mstype, int rv) |
| { |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| int to_nodeid, error; |
| |
| to_nodeid = lkb->lkb_nodeid; |
| |
| error = create_message(r, lkb, to_nodeid, mstype, &ms, &mh); |
| if (error) |
| goto out; |
| |
| send_args(r, lkb, ms); |
| |
| ms->m_result = rv; |
| |
| error = send_message(mh, ms); |
| out: |
| return error; |
| } |
| |
| static int send_request_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv) |
| { |
| return send_common_reply(r, lkb, DLM_MSG_REQUEST_REPLY, rv); |
| } |
| |
| static int send_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv) |
| { |
| return send_common_reply(r, lkb, DLM_MSG_CONVERT_REPLY, rv); |
| } |
| |
| static int send_unlock_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv) |
| { |
| return send_common_reply(r, lkb, DLM_MSG_UNLOCK_REPLY, rv); |
| } |
| |
| static int send_cancel_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv) |
| { |
| return send_common_reply(r, lkb, DLM_MSG_CANCEL_REPLY, rv); |
| } |
| |
| static int send_lookup_reply(struct dlm_ls *ls, struct dlm_message *ms_in, |
| int ret_nodeid, int rv) |
| { |
| struct dlm_rsb *r = &ls->ls_stub_rsb; |
| struct dlm_message *ms; |
| struct dlm_mhandle *mh; |
| int error, nodeid = ms_in->m_header.h_nodeid; |
| |
| error = create_message(r, NULL, nodeid, DLM_MSG_LOOKUP_REPLY, &ms, &mh); |
| if (error) |
| goto out; |
| |
| ms->m_lkid = ms_in->m_lkid; |
| ms->m_result = rv; |
| ms->m_nodeid = ret_nodeid; |
| |
| error = send_message(mh, ms); |
| out: |
| return error; |
| } |
| |
| /* which args we save from a received message depends heavily on the type |
| of message, unlike the send side where we can safely send everything about |
| the lkb for any type of message */ |
| |
| static void receive_flags(struct dlm_lkb *lkb, struct dlm_message *ms) |
| { |
| lkb->lkb_exflags = ms->m_exflags; |
| lkb->lkb_sbflags = ms->m_sbflags; |
| lkb->lkb_flags = (lkb->lkb_flags & 0xFFFF0000) | |
| (ms->m_flags & 0x0000FFFF); |
| } |
| |
| static void receive_flags_reply(struct dlm_lkb *lkb, struct dlm_message *ms) |
| { |
| lkb->lkb_sbflags = ms->m_sbflags; |
| lkb->lkb_flags = (lkb->lkb_flags & 0xFFFF0000) | |
| (ms->m_flags & 0x0000FFFF); |
| } |
| |
| static int receive_extralen(struct dlm_message *ms) |
| { |
| return (ms->m_header.h_length - sizeof(struct dlm_message)); |
| } |
| |
| static int receive_lvb(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_message *ms) |
| { |
| int len; |
| |
| if (lkb->lkb_exflags & DLM_LKF_VALBLK) { |
| if (!lkb->lkb_lvbptr) |
| lkb->lkb_lvbptr = dlm_allocate_lvb(ls); |
| if (!lkb->lkb_lvbptr) |
| return -ENOMEM; |
| len = receive_extralen(ms); |
| if (len > DLM_RESNAME_MAXLEN) |
| len = DLM_RESNAME_MAXLEN; |
| memcpy(lkb->lkb_lvbptr, ms->m_extra, len); |
| } |
| return 0; |
| } |
| |
| static void fake_bastfn(void *astparam, int mode) |
| { |
| log_print("fake_bastfn should not be called"); |
| } |
| |
| static void fake_astfn(void *astparam) |
| { |
| log_print("fake_astfn should not be called"); |
| } |
| |
| static int receive_request_args(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_message *ms) |
| { |
| lkb->lkb_nodeid = ms->m_header.h_nodeid; |
| lkb->lkb_ownpid = ms->m_pid; |
| lkb->lkb_remid = ms->m_lkid; |
| lkb->lkb_grmode = DLM_LOCK_IV; |
| lkb->lkb_rqmode = ms->m_rqmode; |
| |
| lkb->lkb_bastfn = (ms->m_asts & AST_BAST) ? &fake_bastfn : NULL; |
| lkb->lkb_astfn = (ms->m_asts & AST_COMP) ? &fake_astfn : NULL; |
| |
| if (lkb->lkb_exflags & DLM_LKF_VALBLK) { |
| /* lkb was just created so there won't be an lvb yet */ |
| lkb->lkb_lvbptr = dlm_allocate_lvb(ls); |
| if (!lkb->lkb_lvbptr) |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| static int receive_convert_args(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_message *ms) |
| { |
| if (lkb->lkb_status != DLM_LKSTS_GRANTED) |
| return -EBUSY; |
| |
| if (receive_lvb(ls, lkb, ms)) |
| return -ENOMEM; |
| |
| lkb->lkb_rqmode = ms->m_rqmode; |
| lkb->lkb_lvbseq = ms->m_lvbseq; |
| |
| return 0; |
| } |
| |
| static int receive_unlock_args(struct dlm_ls *ls, struct dlm_lkb *lkb, |
| struct dlm_message *ms) |
| { |
| if (receive_lvb(ls, lkb, ms)) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| /* We fill in the stub-lkb fields with the info that send_xxxx_reply() |
| uses to send a reply and that the remote end uses to process the reply. */ |
| |
| static void setup_stub_lkb(struct dlm_ls *ls, struct dlm_message *ms) |
| { |
| struct dlm_lkb *lkb = &ls->ls_stub_lkb; |
| lkb->lkb_nodeid = ms->m_header.h_nodeid; |
| lkb->lkb_remid = ms->m_lkid; |
| } |
| |
| /* This is called after the rsb is locked so that we can safely inspect |
| fields in the lkb. */ |
| |
| static int validate_message(struct dlm_lkb *lkb, struct dlm_message *ms) |
| { |
| int from = ms->m_header.h_nodeid; |
| int error = 0; |
| |
| switch (ms->m_type) { |
| case DLM_MSG_CONVERT: |
| case DLM_MSG_UNLOCK: |
| case DLM_MSG_CANCEL: |
| if (!is_master_copy(lkb) || lkb->lkb_nodeid != from) |
| error = -EINVAL; |
| break; |
| |
| case DLM_MSG_CONVERT_REPLY: |
| case DLM_MSG_UNLOCK_REPLY: |
| case DLM_MSG_CANCEL_REPLY: |
| case DLM_MSG_GRANT: |
| case DLM_MSG_BAST: |
| if (!is_process_copy(lkb) || lkb->lkb_nodeid != from) |
| error = -EINVAL; |
| break; |
| |
| case DLM_MSG_REQUEST_REPLY: |
| if (!is_process_copy(lkb)) |
| error = -EINVAL; |
| else if (lkb->lkb_nodeid != -1 && lkb->lkb_nodeid != from) |
| error = -EINVAL; |
| break; |
| |
| default: |
| error = -EINVAL; |
| } |
| |
| if (error) |
| log_error(lkb |