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682 lines
17 KiB
682 lines
17 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* userdlm.c |
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* |
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* Code which implements the kernel side of a minimal userspace |
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* interface to our DLM. |
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* |
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* Many of the functions here are pared down versions of dlmglue.c |
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* functions. |
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* |
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* Copyright (C) 2003, 2004 Oracle. All rights reserved. |
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*/ |
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#include <linux/signal.h> |
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#include <linux/sched/signal.h> |
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|
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#include <linux/module.h> |
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#include <linux/fs.h> |
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#include <linux/types.h> |
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#include <linux/crc32.h> |
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#include "../ocfs2_lockingver.h" |
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#include "../stackglue.h" |
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#include "userdlm.h" |
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#define MLOG_MASK_PREFIX ML_DLMFS |
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#include "../cluster/masklog.h" |
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static inline struct user_lock_res *user_lksb_to_lock_res(struct ocfs2_dlm_lksb *lksb) |
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{ |
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return container_of(lksb, struct user_lock_res, l_lksb); |
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} |
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static inline int user_check_wait_flag(struct user_lock_res *lockres, |
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int flag) |
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{ |
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int ret; |
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spin_lock(&lockres->l_lock); |
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ret = lockres->l_flags & flag; |
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spin_unlock(&lockres->l_lock); |
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return ret; |
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} |
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static inline void user_wait_on_busy_lock(struct user_lock_res *lockres) |
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{ |
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wait_event(lockres->l_event, |
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!user_check_wait_flag(lockres, USER_LOCK_BUSY)); |
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} |
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static inline void user_wait_on_blocked_lock(struct user_lock_res *lockres) |
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{ |
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wait_event(lockres->l_event, |
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!user_check_wait_flag(lockres, USER_LOCK_BLOCKED)); |
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} |
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/* I heart container_of... */ |
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static inline struct ocfs2_cluster_connection * |
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cluster_connection_from_user_lockres(struct user_lock_res *lockres) |
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{ |
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struct dlmfs_inode_private *ip; |
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ip = container_of(lockres, |
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struct dlmfs_inode_private, |
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ip_lockres); |
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return ip->ip_conn; |
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} |
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static struct inode * |
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user_dlm_inode_from_user_lockres(struct user_lock_res *lockres) |
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{ |
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struct dlmfs_inode_private *ip; |
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ip = container_of(lockres, |
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struct dlmfs_inode_private, |
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ip_lockres); |
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return &ip->ip_vfs_inode; |
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} |
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static inline void user_recover_from_dlm_error(struct user_lock_res *lockres) |
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{ |
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spin_lock(&lockres->l_lock); |
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lockres->l_flags &= ~USER_LOCK_BUSY; |
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spin_unlock(&lockres->l_lock); |
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} |
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#define user_log_dlm_error(_func, _stat, _lockres) do { \ |
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mlog(ML_ERROR, "Dlm error %d while calling %s on " \ |
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"resource %.*s\n", _stat, _func, \ |
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_lockres->l_namelen, _lockres->l_name); \ |
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} while (0) |
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/* WARNING: This function lives in a world where the only three lock |
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* levels are EX, PR, and NL. It *will* have to be adjusted when more |
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* lock types are added. */ |
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static inline int user_highest_compat_lock_level(int level) |
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{ |
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int new_level = DLM_LOCK_EX; |
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if (level == DLM_LOCK_EX) |
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new_level = DLM_LOCK_NL; |
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else if (level == DLM_LOCK_PR) |
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new_level = DLM_LOCK_PR; |
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return new_level; |
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} |
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static void user_ast(struct ocfs2_dlm_lksb *lksb) |
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{ |
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struct user_lock_res *lockres = user_lksb_to_lock_res(lksb); |
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int status; |
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mlog(ML_BASTS, "AST fired for lockres %.*s, level %d => %d\n", |
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lockres->l_namelen, lockres->l_name, lockres->l_level, |
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lockres->l_requested); |
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spin_lock(&lockres->l_lock); |
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status = ocfs2_dlm_lock_status(&lockres->l_lksb); |
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if (status) { |
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mlog(ML_ERROR, "lksb status value of %u on lockres %.*s\n", |
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status, lockres->l_namelen, lockres->l_name); |
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spin_unlock(&lockres->l_lock); |
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return; |
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} |
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mlog_bug_on_msg(lockres->l_requested == DLM_LOCK_IV, |
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"Lockres %.*s, requested ivmode. flags 0x%x\n", |
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lockres->l_namelen, lockres->l_name, lockres->l_flags); |
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/* we're downconverting. */ |
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if (lockres->l_requested < lockres->l_level) { |
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if (lockres->l_requested <= |
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user_highest_compat_lock_level(lockres->l_blocking)) { |
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lockres->l_blocking = DLM_LOCK_NL; |
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lockres->l_flags &= ~USER_LOCK_BLOCKED; |
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} |
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} |
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lockres->l_level = lockres->l_requested; |
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lockres->l_requested = DLM_LOCK_IV; |
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lockres->l_flags |= USER_LOCK_ATTACHED; |
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lockres->l_flags &= ~USER_LOCK_BUSY; |
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spin_unlock(&lockres->l_lock); |
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wake_up(&lockres->l_event); |
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} |
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static inline void user_dlm_grab_inode_ref(struct user_lock_res *lockres) |
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{ |
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struct inode *inode; |
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inode = user_dlm_inode_from_user_lockres(lockres); |
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if (!igrab(inode)) |
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BUG(); |
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} |
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static void user_dlm_unblock_lock(struct work_struct *work); |
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static void __user_dlm_queue_lockres(struct user_lock_res *lockres) |
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{ |
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if (!(lockres->l_flags & USER_LOCK_QUEUED)) { |
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user_dlm_grab_inode_ref(lockres); |
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INIT_WORK(&lockres->l_work, user_dlm_unblock_lock); |
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queue_work(user_dlm_worker, &lockres->l_work); |
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lockres->l_flags |= USER_LOCK_QUEUED; |
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} |
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} |
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static void __user_dlm_cond_queue_lockres(struct user_lock_res *lockres) |
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{ |
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int queue = 0; |
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if (!(lockres->l_flags & USER_LOCK_BLOCKED)) |
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return; |
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switch (lockres->l_blocking) { |
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case DLM_LOCK_EX: |
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if (!lockres->l_ex_holders && !lockres->l_ro_holders) |
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queue = 1; |
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break; |
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case DLM_LOCK_PR: |
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if (!lockres->l_ex_holders) |
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queue = 1; |
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break; |
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default: |
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BUG(); |
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} |
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if (queue) |
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__user_dlm_queue_lockres(lockres); |
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} |
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static void user_bast(struct ocfs2_dlm_lksb *lksb, int level) |
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{ |
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struct user_lock_res *lockres = user_lksb_to_lock_res(lksb); |
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mlog(ML_BASTS, "BAST fired for lockres %.*s, blocking %d, level %d\n", |
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lockres->l_namelen, lockres->l_name, level, lockres->l_level); |
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spin_lock(&lockres->l_lock); |
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lockres->l_flags |= USER_LOCK_BLOCKED; |
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if (level > lockres->l_blocking) |
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lockres->l_blocking = level; |
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__user_dlm_queue_lockres(lockres); |
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spin_unlock(&lockres->l_lock); |
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wake_up(&lockres->l_event); |
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} |
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static void user_unlock_ast(struct ocfs2_dlm_lksb *lksb, int status) |
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{ |
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struct user_lock_res *lockres = user_lksb_to_lock_res(lksb); |
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mlog(ML_BASTS, "UNLOCK AST fired for lockres %.*s, flags 0x%x\n", |
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lockres->l_namelen, lockres->l_name, lockres->l_flags); |
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if (status) |
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mlog(ML_ERROR, "dlm returns status %d\n", status); |
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spin_lock(&lockres->l_lock); |
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/* The teardown flag gets set early during the unlock process, |
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* so test the cancel flag to make sure that this ast isn't |
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* for a concurrent cancel. */ |
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if (lockres->l_flags & USER_LOCK_IN_TEARDOWN |
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&& !(lockres->l_flags & USER_LOCK_IN_CANCEL)) { |
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lockres->l_level = DLM_LOCK_IV; |
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} else if (status == DLM_CANCELGRANT) { |
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/* We tried to cancel a convert request, but it was |
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* already granted. Don't clear the busy flag - the |
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* ast should've done this already. */ |
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BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL)); |
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lockres->l_flags &= ~USER_LOCK_IN_CANCEL; |
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goto out_noclear; |
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} else { |
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BUG_ON(!(lockres->l_flags & USER_LOCK_IN_CANCEL)); |
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/* Cancel succeeded, we want to re-queue */ |
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lockres->l_requested = DLM_LOCK_IV; /* cancel an |
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* upconvert |
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* request. */ |
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lockres->l_flags &= ~USER_LOCK_IN_CANCEL; |
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/* we want the unblock thread to look at it again |
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* now. */ |
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if (lockres->l_flags & USER_LOCK_BLOCKED) |
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__user_dlm_queue_lockres(lockres); |
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} |
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lockres->l_flags &= ~USER_LOCK_BUSY; |
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out_noclear: |
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spin_unlock(&lockres->l_lock); |
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wake_up(&lockres->l_event); |
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} |
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/* |
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* This is the userdlmfs locking protocol version. |
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* |
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* See fs/ocfs2/dlmglue.c for more details on locking versions. |
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*/ |
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static struct ocfs2_locking_protocol user_dlm_lproto = { |
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.lp_max_version = { |
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.pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR, |
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.pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR, |
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}, |
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.lp_lock_ast = user_ast, |
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.lp_blocking_ast = user_bast, |
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.lp_unlock_ast = user_unlock_ast, |
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}; |
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static inline void user_dlm_drop_inode_ref(struct user_lock_res *lockres) |
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{ |
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struct inode *inode; |
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inode = user_dlm_inode_from_user_lockres(lockres); |
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iput(inode); |
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} |
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static void user_dlm_unblock_lock(struct work_struct *work) |
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{ |
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int new_level, status; |
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struct user_lock_res *lockres = |
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container_of(work, struct user_lock_res, l_work); |
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struct ocfs2_cluster_connection *conn = |
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cluster_connection_from_user_lockres(lockres); |
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mlog(0, "lockres %.*s\n", lockres->l_namelen, lockres->l_name); |
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spin_lock(&lockres->l_lock); |
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mlog_bug_on_msg(!(lockres->l_flags & USER_LOCK_QUEUED), |
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"Lockres %.*s, flags 0x%x\n", |
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lockres->l_namelen, lockres->l_name, lockres->l_flags); |
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/* notice that we don't clear USER_LOCK_BLOCKED here. If it's |
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* set, we want user_ast clear it. */ |
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lockres->l_flags &= ~USER_LOCK_QUEUED; |
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/* It's valid to get here and no longer be blocked - if we get |
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* several basts in a row, we might be queued by the first |
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* one, the unblock thread might run and clear the queued |
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* flag, and finally we might get another bast which re-queues |
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* us before our ast for the downconvert is called. */ |
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if (!(lockres->l_flags & USER_LOCK_BLOCKED)) { |
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mlog(ML_BASTS, "lockres %.*s USER_LOCK_BLOCKED\n", |
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lockres->l_namelen, lockres->l_name); |
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spin_unlock(&lockres->l_lock); |
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goto drop_ref; |
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} |
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if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { |
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mlog(ML_BASTS, "lockres %.*s USER_LOCK_IN_TEARDOWN\n", |
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lockres->l_namelen, lockres->l_name); |
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spin_unlock(&lockres->l_lock); |
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goto drop_ref; |
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} |
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if (lockres->l_flags & USER_LOCK_BUSY) { |
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if (lockres->l_flags & USER_LOCK_IN_CANCEL) { |
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mlog(ML_BASTS, "lockres %.*s USER_LOCK_IN_CANCEL\n", |
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lockres->l_namelen, lockres->l_name); |
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spin_unlock(&lockres->l_lock); |
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goto drop_ref; |
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} |
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lockres->l_flags |= USER_LOCK_IN_CANCEL; |
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spin_unlock(&lockres->l_lock); |
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status = ocfs2_dlm_unlock(conn, &lockres->l_lksb, |
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DLM_LKF_CANCEL); |
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if (status) |
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user_log_dlm_error("ocfs2_dlm_unlock", status, lockres); |
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goto drop_ref; |
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} |
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/* If there are still incompat holders, we can exit safely |
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* without worrying about re-queueing this lock as that will |
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* happen on the last call to user_cluster_unlock. */ |
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if ((lockres->l_blocking == DLM_LOCK_EX) |
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&& (lockres->l_ex_holders || lockres->l_ro_holders)) { |
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spin_unlock(&lockres->l_lock); |
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mlog(ML_BASTS, "lockres %.*s, EX/PR Holders %u,%u\n", |
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lockres->l_namelen, lockres->l_name, |
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lockres->l_ex_holders, lockres->l_ro_holders); |
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goto drop_ref; |
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} |
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if ((lockres->l_blocking == DLM_LOCK_PR) |
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&& lockres->l_ex_holders) { |
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spin_unlock(&lockres->l_lock); |
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mlog(ML_BASTS, "lockres %.*s, EX Holders %u\n", |
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lockres->l_namelen, lockres->l_name, |
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lockres->l_ex_holders); |
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goto drop_ref; |
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} |
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/* yay, we can downconvert now. */ |
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new_level = user_highest_compat_lock_level(lockres->l_blocking); |
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lockres->l_requested = new_level; |
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lockres->l_flags |= USER_LOCK_BUSY; |
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mlog(ML_BASTS, "lockres %.*s, downconvert %d => %d\n", |
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lockres->l_namelen, lockres->l_name, lockres->l_level, new_level); |
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spin_unlock(&lockres->l_lock); |
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/* need lock downconvert request now... */ |
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status = ocfs2_dlm_lock(conn, new_level, &lockres->l_lksb, |
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DLM_LKF_CONVERT|DLM_LKF_VALBLK, |
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lockres->l_name, |
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lockres->l_namelen); |
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if (status) { |
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user_log_dlm_error("ocfs2_dlm_lock", status, lockres); |
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user_recover_from_dlm_error(lockres); |
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} |
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drop_ref: |
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user_dlm_drop_inode_ref(lockres); |
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} |
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static inline void user_dlm_inc_holders(struct user_lock_res *lockres, |
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int level) |
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{ |
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switch(level) { |
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case DLM_LOCK_EX: |
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lockres->l_ex_holders++; |
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break; |
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case DLM_LOCK_PR: |
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lockres->l_ro_holders++; |
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break; |
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default: |
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BUG(); |
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} |
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} |
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/* predict what lock level we'll be dropping down to on behalf |
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* of another node, and return true if the currently wanted |
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* level will be compatible with it. */ |
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static inline int |
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user_may_continue_on_blocked_lock(struct user_lock_res *lockres, |
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int wanted) |
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{ |
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BUG_ON(!(lockres->l_flags & USER_LOCK_BLOCKED)); |
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return wanted <= user_highest_compat_lock_level(lockres->l_blocking); |
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} |
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int user_dlm_cluster_lock(struct user_lock_res *lockres, |
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int level, |
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int lkm_flags) |
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{ |
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int status, local_flags; |
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struct ocfs2_cluster_connection *conn = |
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cluster_connection_from_user_lockres(lockres); |
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if (level != DLM_LOCK_EX && |
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level != DLM_LOCK_PR) { |
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mlog(ML_ERROR, "lockres %.*s: invalid request!\n", |
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lockres->l_namelen, lockres->l_name); |
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status = -EINVAL; |
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goto bail; |
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} |
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mlog(ML_BASTS, "lockres %.*s, level %d, flags = 0x%x\n", |
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lockres->l_namelen, lockres->l_name, level, lkm_flags); |
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again: |
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if (signal_pending(current)) { |
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status = -ERESTARTSYS; |
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goto bail; |
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} |
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spin_lock(&lockres->l_lock); |
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if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { |
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spin_unlock(&lockres->l_lock); |
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status = -EAGAIN; |
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goto bail; |
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} |
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|
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/* We only compare against the currently granted level |
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* here. If the lock is blocked waiting on a downconvert, |
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* we'll get caught below. */ |
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if ((lockres->l_flags & USER_LOCK_BUSY) && |
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(level > lockres->l_level)) { |
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/* is someone sitting in dlm_lock? If so, wait on |
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* them. */ |
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spin_unlock(&lockres->l_lock); |
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user_wait_on_busy_lock(lockres); |
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goto again; |
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} |
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if ((lockres->l_flags & USER_LOCK_BLOCKED) && |
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(!user_may_continue_on_blocked_lock(lockres, level))) { |
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/* is the lock is currently blocked on behalf of |
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* another node */ |
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spin_unlock(&lockres->l_lock); |
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user_wait_on_blocked_lock(lockres); |
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goto again; |
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} |
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if (level > lockres->l_level) { |
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local_flags = lkm_flags | DLM_LKF_VALBLK; |
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if (lockres->l_level != DLM_LOCK_IV) |
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local_flags |= DLM_LKF_CONVERT; |
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|
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lockres->l_requested = level; |
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lockres->l_flags |= USER_LOCK_BUSY; |
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spin_unlock(&lockres->l_lock); |
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|
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BUG_ON(level == DLM_LOCK_IV); |
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BUG_ON(level == DLM_LOCK_NL); |
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|
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/* call dlm_lock to upgrade lock now */ |
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status = ocfs2_dlm_lock(conn, level, &lockres->l_lksb, |
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local_flags, lockres->l_name, |
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lockres->l_namelen); |
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if (status) { |
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if ((lkm_flags & DLM_LKF_NOQUEUE) && |
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(status != -EAGAIN)) |
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user_log_dlm_error("ocfs2_dlm_lock", |
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status, lockres); |
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user_recover_from_dlm_error(lockres); |
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goto bail; |
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} |
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user_wait_on_busy_lock(lockres); |
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goto again; |
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} |
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user_dlm_inc_holders(lockres, level); |
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spin_unlock(&lockres->l_lock); |
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|
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status = 0; |
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bail: |
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return status; |
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} |
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|
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static inline void user_dlm_dec_holders(struct user_lock_res *lockres, |
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int level) |
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{ |
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switch(level) { |
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case DLM_LOCK_EX: |
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BUG_ON(!lockres->l_ex_holders); |
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lockres->l_ex_holders--; |
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break; |
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case DLM_LOCK_PR: |
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BUG_ON(!lockres->l_ro_holders); |
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lockres->l_ro_holders--; |
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break; |
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default: |
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BUG(); |
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} |
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} |
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|
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void user_dlm_cluster_unlock(struct user_lock_res *lockres, |
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int level) |
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{ |
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if (level != DLM_LOCK_EX && |
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level != DLM_LOCK_PR) { |
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mlog(ML_ERROR, "lockres %.*s: invalid request!\n", |
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lockres->l_namelen, lockres->l_name); |
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return; |
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} |
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|
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spin_lock(&lockres->l_lock); |
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user_dlm_dec_holders(lockres, level); |
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__user_dlm_cond_queue_lockres(lockres); |
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spin_unlock(&lockres->l_lock); |
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} |
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|
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void user_dlm_write_lvb(struct inode *inode, |
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const char *val, |
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unsigned int len) |
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{ |
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struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; |
|
char *lvb; |
|
|
|
BUG_ON(len > DLM_LVB_LEN); |
|
|
|
spin_lock(&lockres->l_lock); |
|
|
|
BUG_ON(lockres->l_level < DLM_LOCK_EX); |
|
lvb = ocfs2_dlm_lvb(&lockres->l_lksb); |
|
memcpy(lvb, val, len); |
|
|
|
spin_unlock(&lockres->l_lock); |
|
} |
|
|
|
bool user_dlm_read_lvb(struct inode *inode, char *val) |
|
{ |
|
struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; |
|
char *lvb; |
|
bool ret = true; |
|
|
|
spin_lock(&lockres->l_lock); |
|
|
|
BUG_ON(lockres->l_level < DLM_LOCK_PR); |
|
if (ocfs2_dlm_lvb_valid(&lockres->l_lksb)) { |
|
lvb = ocfs2_dlm_lvb(&lockres->l_lksb); |
|
memcpy(val, lvb, DLM_LVB_LEN); |
|
} else |
|
ret = false; |
|
|
|
spin_unlock(&lockres->l_lock); |
|
return ret; |
|
} |
|
|
|
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 = DLM_LOCK_IV; |
|
lockres->l_requested = DLM_LOCK_IV; |
|
lockres->l_blocking = DLM_LOCK_IV; |
|
|
|
/* 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); |
|
lockres->l_namelen = dentry->d_name.len; |
|
} |
|
|
|
int user_dlm_destroy_lock(struct user_lock_res *lockres) |
|
{ |
|
int status = -EBUSY; |
|
struct ocfs2_cluster_connection *conn = |
|
cluster_connection_from_user_lockres(lockres); |
|
|
|
mlog(ML_BASTS, "lockres %.*s\n", lockres->l_namelen, lockres->l_name); |
|
|
|
spin_lock(&lockres->l_lock); |
|
if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { |
|
spin_unlock(&lockres->l_lock); |
|
goto bail; |
|
} |
|
|
|
lockres->l_flags |= USER_LOCK_IN_TEARDOWN; |
|
|
|
while (lockres->l_flags & USER_LOCK_BUSY) { |
|
spin_unlock(&lockres->l_lock); |
|
|
|
user_wait_on_busy_lock(lockres); |
|
|
|
spin_lock(&lockres->l_lock); |
|
} |
|
|
|
if (lockres->l_ro_holders || lockres->l_ex_holders) { |
|
lockres->l_flags &= ~USER_LOCK_IN_TEARDOWN; |
|
spin_unlock(&lockres->l_lock); |
|
goto bail; |
|
} |
|
|
|
status = 0; |
|
if (!(lockres->l_flags & USER_LOCK_ATTACHED)) { |
|
/* |
|
* lock is never requested, leave USER_LOCK_IN_TEARDOWN set |
|
* to avoid new lock request coming in. |
|
*/ |
|
spin_unlock(&lockres->l_lock); |
|
goto bail; |
|
} |
|
|
|
lockres->l_flags |= USER_LOCK_BUSY; |
|
spin_unlock(&lockres->l_lock); |
|
|
|
status = ocfs2_dlm_unlock(conn, &lockres->l_lksb, DLM_LKF_VALBLK); |
|
if (status) { |
|
spin_lock(&lockres->l_lock); |
|
lockres->l_flags &= ~USER_LOCK_IN_TEARDOWN; |
|
lockres->l_flags &= ~USER_LOCK_BUSY; |
|
spin_unlock(&lockres->l_lock); |
|
user_log_dlm_error("ocfs2_dlm_unlock", status, lockres); |
|
goto bail; |
|
} |
|
|
|
user_wait_on_busy_lock(lockres); |
|
|
|
status = 0; |
|
bail: |
|
return status; |
|
} |
|
|
|
static void user_dlm_recovery_handler_noop(int node_num, |
|
void *recovery_data) |
|
{ |
|
/* We ignore recovery events */ |
|
return; |
|
} |
|
|
|
void user_dlm_set_locking_protocol(void) |
|
{ |
|
ocfs2_stack_glue_set_max_proto_version(&user_dlm_lproto.lp_max_version); |
|
} |
|
|
|
struct ocfs2_cluster_connection *user_dlm_register(const struct qstr *name) |
|
{ |
|
int rc; |
|
struct ocfs2_cluster_connection *conn; |
|
|
|
rc = ocfs2_cluster_connect_agnostic(name->name, name->len, |
|
&user_dlm_lproto, |
|
user_dlm_recovery_handler_noop, |
|
NULL, &conn); |
|
if (rc) |
|
mlog_errno(rc); |
|
|
|
return rc ? ERR_PTR(rc) : conn; |
|
} |
|
|
|
void user_dlm_unregister(struct ocfs2_cluster_connection *conn) |
|
{ |
|
ocfs2_cluster_disconnect(conn, 0); |
|
}
|
|
|