diff options
author | Mark Fasheh <mark.fasheh@oracle.com> | 2005-12-15 14:31:23 -0800 |
---|---|---|
committer | Joel Becker <joel.becker@oracle.com> | 2006-01-03 11:45:47 -0800 |
commit | 8df08c89c668e1bd922a053fdb5ba1fadbecbb38 (patch) | |
tree | ab1febb732c01a66c0a9bfe9c8952ba2bb66fba8 /fs/ocfs2/dlm/userdlm.c | |
parent | 6714d8e86bf443f6f7af50f9d432025649f091f5 (diff) |
[PATCH] OCFS2: The Second Oracle Cluster Filesystem
dlmfs: A minimal dlm userspace interface implemented via a virtual
file system.
Most of the OCFS2 tools make use of this to take cluster locks when
doing operations on the file system.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>
Diffstat (limited to 'fs/ocfs2/dlm/userdlm.c')
-rw-r--r-- | fs/ocfs2/dlm/userdlm.c | 658 |
1 files changed, 658 insertions, 0 deletions
diff --git a/fs/ocfs2/dlm/userdlm.c b/fs/ocfs2/dlm/userdlm.c new file mode 100644 index 000000000000..e1fdd288796e --- /dev/null +++ b/fs/ocfs2/dlm/userdlm.c @@ -0,0 +1,658 @@ +/* -*- 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 <asm/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; + } + + /* 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) + 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 { + 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. */ + __user_dlm_queue_lockres(lockres); + } + + lockres->l_flags &= ~USER_LOCK_BUSY; + 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); + + BUG_ON(!(lockres->l_flags & USER_LOCK_BLOCKED)); + BUG_ON(!(lockres->l_flags & USER_LOCK_QUEUED)); + + /* notice that we don't clear USER_LOCK_BLOCKED here. That's + * for user_ast to do. */ + lockres->l_flags &= ~USER_LOCK_QUEUED; + + 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, "BUSY flag detected...\n"); + 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_CANCELGRANT) { + /* If we got this, then the ast was fired + * before we could cancel. We cleanup our + * state, and restart the function. */ + spin_lock(&lockres->l_lock); + lockres->l_flags &= ~USER_LOCK_IN_CANCEL; + spin_unlock(&lockres->l_lock); + } else 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); +} |