| /* -*- mode: c; c-basic-offset: 8; -*- |
| * vim: noexpandtab sw=8 ts=8 sts=0: |
| * |
| * userdlm.c |
| * |
| * Code which implements the kernel side of a minimal userspace |
| * interface to our DLM. |
| * |
| * Many of the functions here are pared down versions of dlmglue.c |
| * functions. |
| * |
| * Copyright (C) 2003, 2004 Oracle. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| */ |
| |
| #include <linux/signal.h> |
| |
| #include <linux/module.h> |
| #include <linux/fs.h> |
| #include <linux/types.h> |
| #include <linux/crc32.h> |
| |
| |
| #include "cluster/nodemanager.h" |
| #include "cluster/heartbeat.h" |
| #include "cluster/tcp.h" |
| |
| #include "dlmapi.h" |
| |
| #include "userdlm.h" |
| |
| #define MLOG_MASK_PREFIX ML_DLMFS |
| #include "cluster/masklog.h" |
| |
| static inline int user_check_wait_flag(struct user_lock_res *lockres, |
| int flag) |
| { |
| int ret; |
| |
| spin_lock(&lockres->l_lock); |
| ret = lockres->l_flags & flag; |
| spin_unlock(&lockres->l_lock); |
| |
| return ret; |
| } |
| |
| static inline void user_wait_on_busy_lock(struct user_lock_res *lockres) |
| |
| { |
| wait_event(lockres->l_event, |
| !user_check_wait_flag(lockres, USER_LOCK_BUSY)); |
| } |
| |
| static inline void user_wait_on_blocked_lock(struct user_lock_res *lockres) |
| |
| { |
| wait_event(lockres->l_event, |
| !user_check_wait_flag(lockres, USER_LOCK_BLOCKED)); |
| } |
| |
| /* I heart container_of... */ |
| static inline struct dlm_ctxt * |
| dlm_ctxt_from_user_lockres(struct user_lock_res *lockres) |
| { |
| struct dlmfs_inode_private *ip; |
| |
| ip = container_of(lockres, |
| struct dlmfs_inode_private, |
| ip_lockres); |
| return ip->ip_dlm; |
| } |
| |
| static struct inode * |
| user_dlm_inode_from_user_lockres(struct user_lock_res *lockres) |
| { |
| struct dlmfs_inode_private *ip; |
| |
| ip = container_of(lockres, |
| struct dlmfs_inode_private, |
| ip_lockres); |
| return &ip->ip_vfs_inode; |
| } |
| |
| static inline void user_recover_from_dlm_error(struct user_lock_res *lockres) |
| { |
| spin_lock(&lockres->l_lock); |
| lockres->l_flags &= ~USER_LOCK_BUSY; |
| spin_unlock(&lockres->l_lock); |
| } |
| |
| #define user_log_dlm_error(_func, _stat, _lockres) do { \ |
| mlog(ML_ERROR, "Dlm error \"%s\" while calling %s on " \ |
| "resource %s: %s\n", dlm_errname(_stat), _func, \ |
| _lockres->l_name, dlm_errmsg(_stat)); \ |
| } while (0) |
| |
| /* WARNING: This function lives in a world where the only three lock |
| * levels are EX, PR, and NL. It *will* have to be adjusted when more |
| * lock types are added. */ |
| static inline int user_highest_compat_lock_level(int level) |
| { |
| int new_level = LKM_EXMODE; |
| |
| if (level == LKM_EXMODE) |
| new_level = LKM_NLMODE; |
| else if (level == LKM_PRMODE) |
| new_level = LKM_PRMODE; |
| return new_level; |
| } |
| |
| static void user_ast(void *opaque) |
| { |
| struct user_lock_res *lockres = opaque; |
| struct dlm_lockstatus *lksb; |
| |
| mlog(0, "AST fired for lockres %s\n", lockres->l_name); |
| |
| spin_lock(&lockres->l_lock); |
| |
| lksb = &(lockres->l_lksb); |
| if (lksb->status != DLM_NORMAL) { |
| mlog(ML_ERROR, "lksb status value of %u on lockres %s\n", |
| lksb->status, lockres->l_name); |
| spin_unlock(&lockres->l_lock); |
| return; |
| } |
| |
| mlog_bug_on_msg(lockres->l_requested == LKM_IVMODE, |
| "Lockres %s, requested ivmode. flags 0x%x\n", |
| lockres->l_name, lockres->l_flags); |
| |
| /* we're downconverting. */ |
| if (lockres->l_requested < lockres->l_level) { |
| if (lockres->l_requested <= |
| user_highest_compat_lock_level(lockres->l_blocking)) { |
| lockres->l_blocking = LKM_NLMODE; |
| lockres->l_flags &= ~USER_LOCK_BLOCKED; |
| } |
| } |
| |
| lockres->l_level = lockres->l_requested; |
| lockres->l_requested = LKM_IVMODE; |
| lockres->l_flags |= USER_LOCK_ATTACHED; |
| lockres->l_flags &= ~USER_LOCK_BUSY; |
| |
| spin_unlock(&lockres->l_lock); |
| |
| wake_up(&lockres->l_event); |
| } |
| |
| static inline void user_dlm_grab_inode_ref(struct user_lock_res *lockres) |
| { |
| struct inode *inode; |
| inode = user_dlm_inode_from_user_lockres(lockres); |
| if (!igrab(inode)) |
| BUG(); |
| } |
| |
| static void user_dlm_unblock_lock(void *opaque); |
| |
| static void __user_dlm_queue_lockres(struct user_lock_res *lockres) |
| { |
| if (!(lockres->l_flags & USER_LOCK_QUEUED)) { |
| user_dlm_grab_inode_ref(lockres); |
| |
| INIT_WORK(&lockres->l_work, user_dlm_unblock_lock, |
| lockres); |
| |
| queue_work(user_dlm_worker, &lockres->l_work); |
| lockres->l_flags |= USER_LOCK_QUEUED; |
| } |
| } |
| |
| static void __user_dlm_cond_queue_lockres(struct user_lock_res *lockres) |
| { |
| int queue = 0; |
| |
| if (!(lockres->l_flags & USER_LOCK_BLOCKED)) |
| return; |
| |
| switch (lockres->l_blocking) { |
| case LKM_EXMODE: |
| if (!lockres->l_ex_holders && !lockres->l_ro_holders) |
| queue = 1; |
| break; |
| case LKM_PRMODE: |
| if (!lockres->l_ex_holders) |
| queue = 1; |
| break; |
| default: |
| BUG(); |
| } |
| |
| if (queue) |
| __user_dlm_queue_lockres(lockres); |
| } |
| |
| static void user_bast(void *opaque, int level) |
| { |
| struct user_lock_res *lockres = opaque; |
| |
| mlog(0, "Blocking AST fired for lockres %s. Blocking level %d\n", |
| lockres->l_name, level); |
| |
| spin_lock(&lockres->l_lock); |
| lockres->l_flags |= USER_LOCK_BLOCKED; |
| if (level > lockres->l_blocking) |
| lockres->l_blocking = level; |
| |
| __user_dlm_queue_lockres(lockres); |
| spin_unlock(&lockres->l_lock); |
| |
| wake_up(&lockres->l_event); |
| } |
| |
| static void user_unlock_ast(void *opaque, enum dlm_status status) |
| { |
| struct user_lock_res *lockres = opaque; |
| |
| mlog(0, "UNLOCK AST called on lock %s\n", lockres->l_name); |
| |
| if (status != DLM_NORMAL && status != DLM_CANCELGRANT) |
| mlog(ML_ERROR, "Dlm returns status %d\n", status); |
| |
| spin_lock(&lockres->l_lock); |
| if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) |
| lockres->l_level = LKM_IVMODE; |
| else if (status == DLM_CANCELGRANT) { |
| mlog(0, "Lock %s, cancel fails, flags 0x%x\n", |
| lockres->l_name, lockres->l_flags); |
| /* We tried to cancel a convert request, but it was |
| * already granted. Don't clear the busy flag - the |
| * ast should've done this already. */ |
| BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL)); |
| lockres->l_flags &= ~USER_LOCK_IN_CANCEL; |
| goto out_noclear; |
| } else { |
| BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL)); |
| /* Cancel succeeded, we want to re-queue */ |
| mlog(0, "Lock %s, cancel succeeds, flags 0x%x\n", |
| lockres->l_name, lockres->l_flags); |
| lockres->l_requested = LKM_IVMODE; /* cancel an |
| * upconvert |
| * request. */ |
| lockres->l_flags &= ~USER_LOCK_IN_CANCEL; |
| /* we want the unblock thread to look at it again |
| * now. */ |
| if (lockres->l_flags & USER_LOCK_BLOCKED) |
| __user_dlm_queue_lockres(lockres); |
| } |
| |
| lockres->l_flags &= ~USER_LOCK_BUSY; |
| out_noclear: |
| spin_unlock(&lockres->l_lock); |
| |
| wake_up(&lockres->l_event); |
| } |
| |
| static inline void user_dlm_drop_inode_ref(struct user_lock_res *lockres) |
| { |
| struct inode *inode; |
| inode = user_dlm_inode_from_user_lockres(lockres); |
| iput(inode); |
| } |
| |
| static void user_dlm_unblock_lock(void *opaque) |
| { |
| int new_level, status; |
| struct user_lock_res *lockres = (struct user_lock_res *) opaque; |
| struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); |
| |
| mlog(0, "processing lockres %s\n", lockres->l_name); |
| |
| spin_lock(&lockres->l_lock); |
| |
| mlog_bug_on_msg(!(lockres->l_flags & USER_LOCK_QUEUED), |
| "Lockres %s, flags 0x%x\n", |
| lockres->l_name, lockres->l_flags); |
| |
| /* notice that we don't clear USER_LOCK_BLOCKED here. If it's |
| * set, we want user_ast clear it. */ |
| lockres->l_flags &= ~USER_LOCK_QUEUED; |
| |
| /* It's valid to get here and no longer be blocked - if we get |
| * several basts in a row, we might be queued by the first |
| * one, the unblock thread might run and clear the queued |
| * flag, and finally we might get another bast which re-queues |
| * us before our ast for the downconvert is called. */ |
| if (!(lockres->l_flags & USER_LOCK_BLOCKED)) { |
| mlog(0, "Lockres %s, flags 0x%x: queued but not blocking\n", |
| lockres->l_name, lockres->l_flags); |
| spin_unlock(&lockres->l_lock); |
| goto drop_ref; |
| } |
| |
| if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { |
| mlog(0, "lock is in teardown so we do nothing\n"); |
| spin_unlock(&lockres->l_lock); |
| goto drop_ref; |
| } |
| |
| if (lockres->l_flags & USER_LOCK_BUSY) { |
| mlog(0, "Cancel lock %s, flags 0x%x\n", |
| lockres->l_name, lockres->l_flags); |
| |
| if (lockres->l_flags & USER_LOCK_IN_CANCEL) { |
| spin_unlock(&lockres->l_lock); |
| goto drop_ref; |
| } |
| |
| lockres->l_flags |= USER_LOCK_IN_CANCEL; |
| spin_unlock(&lockres->l_lock); |
| |
| status = dlmunlock(dlm, |
| &lockres->l_lksb, |
| LKM_CANCEL, |
| user_unlock_ast, |
| lockres); |
| if (status != DLM_NORMAL) |
| user_log_dlm_error("dlmunlock", status, lockres); |
| goto drop_ref; |
| } |
| |
| /* If there are still incompat holders, we can exit safely |
| * without worrying about re-queueing this lock as that will |
| * happen on the last call to user_cluster_unlock. */ |
| if ((lockres->l_blocking == LKM_EXMODE) |
| && (lockres->l_ex_holders || lockres->l_ro_holders)) { |
| spin_unlock(&lockres->l_lock); |
| mlog(0, "can't downconvert for ex: ro = %u, ex = %u\n", |
| lockres->l_ro_holders, lockres->l_ex_holders); |
| goto drop_ref; |
| } |
| |
| if ((lockres->l_blocking == LKM_PRMODE) |
| && lockres->l_ex_holders) { |
| spin_unlock(&lockres->l_lock); |
| mlog(0, "can't downconvert for pr: ex = %u\n", |
| lockres->l_ex_holders); |
| goto drop_ref; |
| } |
| |
| /* yay, we can downconvert now. */ |
| new_level = user_highest_compat_lock_level(lockres->l_blocking); |
| lockres->l_requested = new_level; |
| lockres->l_flags |= USER_LOCK_BUSY; |
| mlog(0, "Downconvert lock from %d to %d\n", |
| lockres->l_level, new_level); |
| spin_unlock(&lockres->l_lock); |
| |
| /* need lock downconvert request now... */ |
| status = dlmlock(dlm, |
| new_level, |
| &lockres->l_lksb, |
| LKM_CONVERT|LKM_VALBLK, |
| lockres->l_name, |
| user_ast, |
| lockres, |
| user_bast); |
| if (status != DLM_NORMAL) { |
| user_log_dlm_error("dlmlock", status, lockres); |
| user_recover_from_dlm_error(lockres); |
| } |
| |
| drop_ref: |
| user_dlm_drop_inode_ref(lockres); |
| } |
| |
| static inline void user_dlm_inc_holders(struct user_lock_res *lockres, |
| int level) |
| { |
| switch(level) { |
| case LKM_EXMODE: |
| lockres->l_ex_holders++; |
| break; |
| case LKM_PRMODE: |
| lockres->l_ro_holders++; |
| break; |
| default: |
| BUG(); |
| } |
| } |
| |
| /* predict what lock level we'll be dropping down to on behalf |
| * of another node, and return true if the currently wanted |
| * level will be compatible with it. */ |
| static inline int |
| user_may_continue_on_blocked_lock(struct user_lock_res *lockres, |
| int wanted) |
| { |
| BUG_ON(!(lockres->l_flags & USER_LOCK_BLOCKED)); |
| |
| return wanted <= user_highest_compat_lock_level(lockres->l_blocking); |
| } |
| |
| int user_dlm_cluster_lock(struct user_lock_res *lockres, |
| int level, |
| int lkm_flags) |
| { |
| int status, local_flags; |
| struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); |
| |
| if (level != LKM_EXMODE && |
| level != LKM_PRMODE) { |
| mlog(ML_ERROR, "lockres %s: invalid request!\n", |
| lockres->l_name); |
| status = -EINVAL; |
| goto bail; |
| } |
| |
| mlog(0, "lockres %s: asking for %s lock, passed flags = 0x%x\n", |
| lockres->l_name, |
| (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE", |
| lkm_flags); |
| |
| again: |
| if (signal_pending(current)) { |
| status = -ERESTARTSYS; |
| goto bail; |
| } |
| |
| spin_lock(&lockres->l_lock); |
| |
| /* We only compare against the currently granted level |
| * here. If the lock is blocked waiting on a downconvert, |
| * we'll get caught below. */ |
| if ((lockres->l_flags & USER_LOCK_BUSY) && |
| (level > lockres->l_level)) { |
| /* is someone sitting in dlm_lock? If so, wait on |
| * them. */ |
| spin_unlock(&lockres->l_lock); |
| |
| user_wait_on_busy_lock(lockres); |
| goto again; |
| } |
| |
| if ((lockres->l_flags & USER_LOCK_BLOCKED) && |
| (!user_may_continue_on_blocked_lock(lockres, level))) { |
| /* is the lock is currently blocked on behalf of |
| * another node */ |
| spin_unlock(&lockres->l_lock); |
| |
| user_wait_on_blocked_lock(lockres); |
| goto again; |
| } |
| |
| if (level > lockres->l_level) { |
| local_flags = lkm_flags | LKM_VALBLK; |
| if (lockres->l_level != LKM_IVMODE) |
| local_flags |= LKM_CONVERT; |
| |
| lockres->l_requested = level; |
| lockres->l_flags |= USER_LOCK_BUSY; |
| spin_unlock(&lockres->l_lock); |
| |
| BUG_ON(level == LKM_IVMODE); |
| BUG_ON(level == LKM_NLMODE); |
| |
| mlog(0, "lock %s, get lock from %d to level = %d\n", |
| lockres->l_name, lockres->l_level, level); |
| |
| /* call dlm_lock to upgrade lock now */ |
| status = dlmlock(dlm, |
| level, |
| &lockres->l_lksb, |
| local_flags, |
| lockres->l_name, |
| user_ast, |
| lockres, |
| user_bast); |
| if (status != DLM_NORMAL) { |
| if ((lkm_flags & LKM_NOQUEUE) && |
| (status == DLM_NOTQUEUED)) |
| status = -EAGAIN; |
| else { |
| user_log_dlm_error("dlmlock", status, lockres); |
| status = -EINVAL; |
| } |
| user_recover_from_dlm_error(lockres); |
| goto bail; |
| } |
| |
| mlog(0, "lock %s, successfull return from dlmlock\n", |
| lockres->l_name); |
| |
| user_wait_on_busy_lock(lockres); |
| goto again; |
| } |
| |
| user_dlm_inc_holders(lockres, level); |
| spin_unlock(&lockres->l_lock); |
| |
| mlog(0, "lockres %s: Got %s lock!\n", lockres->l_name, |
| (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE"); |
| |
| status = 0; |
| bail: |
| return status; |
| } |
| |
| static inline void user_dlm_dec_holders(struct user_lock_res *lockres, |
| int level) |
| { |
| switch(level) { |
| case LKM_EXMODE: |
| BUG_ON(!lockres->l_ex_holders); |
| lockres->l_ex_holders--; |
| break; |
| case LKM_PRMODE: |
| BUG_ON(!lockres->l_ro_holders); |
| lockres->l_ro_holders--; |
| break; |
| default: |
| BUG(); |
| } |
| } |
| |
| void user_dlm_cluster_unlock(struct user_lock_res *lockres, |
| int level) |
| { |
| if (level != LKM_EXMODE && |
| level != LKM_PRMODE) { |
| mlog(ML_ERROR, "lockres %s: invalid request!\n", lockres->l_name); |
| return; |
| } |
| |
| mlog(0, "lockres %s: dropping %s lock\n", lockres->l_name, |
| (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE"); |
| |
| spin_lock(&lockres->l_lock); |
| user_dlm_dec_holders(lockres, level); |
| __user_dlm_cond_queue_lockres(lockres); |
| spin_unlock(&lockres->l_lock); |
| } |
| |
| void user_dlm_write_lvb(struct inode *inode, |
| const char *val, |
| unsigned int len) |
| { |
| struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; |
| char *lvb = lockres->l_lksb.lvb; |
| |
| BUG_ON(len > DLM_LVB_LEN); |
| |
| spin_lock(&lockres->l_lock); |
| |
| BUG_ON(lockres->l_level < LKM_EXMODE); |
| memcpy(lvb, val, len); |
| |
| spin_unlock(&lockres->l_lock); |
| } |
| |
| void user_dlm_read_lvb(struct inode *inode, |
| char *val, |
| unsigned int len) |
| { |
| struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; |
| char *lvb = lockres->l_lksb.lvb; |
| |
| BUG_ON(len > DLM_LVB_LEN); |
| |
| spin_lock(&lockres->l_lock); |
| |
| BUG_ON(lockres->l_level < LKM_PRMODE); |
| memcpy(val, lvb, len); |
| |
| spin_unlock(&lockres->l_lock); |
| } |
| |
| void user_dlm_lock_res_init(struct user_lock_res *lockres, |
| struct dentry *dentry) |
| { |
| memset(lockres, 0, sizeof(*lockres)); |
| |
| spin_lock_init(&lockres->l_lock); |
| init_waitqueue_head(&lockres->l_event); |
| lockres->l_level = LKM_IVMODE; |
| lockres->l_requested = LKM_IVMODE; |
| lockres->l_blocking = LKM_IVMODE; |
| |
| /* should have been checked before getting here. */ |
| BUG_ON(dentry->d_name.len >= USER_DLM_LOCK_ID_MAX_LEN); |
| |
| memcpy(lockres->l_name, |
| dentry->d_name.name, |
| dentry->d_name.len); |
| } |
| |
| int user_dlm_destroy_lock(struct user_lock_res *lockres) |
| { |
| int status = -EBUSY; |
| struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); |
| |
| mlog(0, "asked to destroy %s\n", lockres->l_name); |
| |
| spin_lock(&lockres->l_lock); |
| while (lockres->l_flags & USER_LOCK_BUSY) { |
| spin_unlock(&lockres->l_lock); |
| |
| mlog(0, "lock %s is busy\n", lockres->l_name); |
| |
| user_wait_on_busy_lock(lockres); |
| |
| spin_lock(&lockres->l_lock); |
| } |
| |
| if (lockres->l_ro_holders || lockres->l_ex_holders) { |
| spin_unlock(&lockres->l_lock); |
| mlog(0, "lock %s has holders\n", lockres->l_name); |
| goto bail; |
| } |
| |
| status = 0; |
| if (!(lockres->l_flags & USER_LOCK_ATTACHED)) { |
| spin_unlock(&lockres->l_lock); |
| mlog(0, "lock %s is not attached\n", lockres->l_name); |
| goto bail; |
| } |
| |
| lockres->l_flags &= ~USER_LOCK_ATTACHED; |
| lockres->l_flags |= USER_LOCK_BUSY; |
| lockres->l_flags |= USER_LOCK_IN_TEARDOWN; |
| spin_unlock(&lockres->l_lock); |
| |
| mlog(0, "unlocking lockres %s\n", lockres->l_name); |
| status = dlmunlock(dlm, |
| &lockres->l_lksb, |
| LKM_VALBLK, |
| user_unlock_ast, |
| lockres); |
| if (status != DLM_NORMAL) { |
| user_log_dlm_error("dlmunlock", status, lockres); |
| status = -EINVAL; |
| goto bail; |
| } |
| |
| user_wait_on_busy_lock(lockres); |
| |
| status = 0; |
| bail: |
| return status; |
| } |
| |
| struct dlm_ctxt *user_dlm_register_context(struct qstr *name) |
| { |
| struct dlm_ctxt *dlm; |
| u32 dlm_key; |
| char *domain; |
| |
| domain = kmalloc(name->len + 1, GFP_KERNEL); |
| if (!domain) { |
| mlog_errno(-ENOMEM); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| dlm_key = crc32_le(0, name->name, name->len); |
| |
| snprintf(domain, name->len + 1, "%.*s", name->len, name->name); |
| |
| dlm = dlm_register_domain(domain, dlm_key); |
| if (IS_ERR(dlm)) |
| mlog_errno(PTR_ERR(dlm)); |
| |
| kfree(domain); |
| return dlm; |
| } |
| |
| void user_dlm_unregister_context(struct dlm_ctxt *dlm) |
| { |
| dlm_unregister_domain(dlm); |
| } |