diff options
Diffstat (limited to 'fs/ocfs2/dlmfs/userdlm.c')
| -rw-r--r-- | fs/ocfs2/dlmfs/userdlm.c | 685 |
1 files changed, 685 insertions, 0 deletions
diff --git a/fs/ocfs2/dlmfs/userdlm.c b/fs/ocfs2/dlmfs/userdlm.c new file mode 100644 index 000000000..8fa289de3 --- /dev/null +++ b/fs/ocfs2/dlmfs/userdlm.c @@ -0,0 +1,685 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* -*- 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. + */ + +#include <linux/signal.h> +#include <linux/sched/signal.h> + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/types.h> +#include <linux/crc32.h> + +#include "../ocfs2_lockingver.h" +#include "../stackglue.h" +#include "userdlm.h" + +#define MLOG_MASK_PREFIX ML_DLMFS +#include "../cluster/masklog.h" + + +static inline struct user_lock_res *user_lksb_to_lock_res(struct ocfs2_dlm_lksb *lksb) +{ + return container_of(lksb, struct user_lock_res, l_lksb); +} + +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 ocfs2_cluster_connection * +cluster_connection_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_conn; +} + +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 %d while calling %s on " \ + "resource %.*s\n", _stat, _func, \ + _lockres->l_namelen, _lockres->l_name); \ +} 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 = DLM_LOCK_EX; + + if (level == DLM_LOCK_EX) + new_level = DLM_LOCK_NL; + else if (level == DLM_LOCK_PR) + new_level = DLM_LOCK_PR; + return new_level; +} + +static void user_ast(struct ocfs2_dlm_lksb *lksb) +{ + struct user_lock_res *lockres = user_lksb_to_lock_res(lksb); + int status; + + mlog(ML_BASTS, "AST fired for lockres %.*s, level %d => %d\n", + lockres->l_namelen, lockres->l_name, lockres->l_level, + lockres->l_requested); + + spin_lock(&lockres->l_lock); + + status = ocfs2_dlm_lock_status(&lockres->l_lksb); + if (status) { + mlog(ML_ERROR, "lksb status value of %u on lockres %.*s\n", + status, lockres->l_namelen, lockres->l_name); + spin_unlock(&lockres->l_lock); + return; + } + + mlog_bug_on_msg(lockres->l_requested == DLM_LOCK_IV, + "Lockres %.*s, requested ivmode. flags 0x%x\n", + lockres->l_namelen, 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 = DLM_LOCK_NL; + lockres->l_flags &= ~USER_LOCK_BLOCKED; + } + } + + lockres->l_level = lockres->l_requested; + lockres->l_requested = DLM_LOCK_IV; + 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(struct work_struct *work); + +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); + + 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 DLM_LOCK_EX: + if (!lockres->l_ex_holders && !lockres->l_ro_holders) + queue = 1; + break; + case DLM_LOCK_PR: + if (!lockres->l_ex_holders) + queue = 1; + break; + default: + BUG(); + } + + if (queue) + __user_dlm_queue_lockres(lockres); +} + +static void user_bast(struct ocfs2_dlm_lksb *lksb, int level) +{ + struct user_lock_res *lockres = user_lksb_to_lock_res(lksb); + + mlog(ML_BASTS, "BAST fired for lockres %.*s, blocking %d, level %d\n", + lockres->l_namelen, lockres->l_name, level, lockres->l_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(struct ocfs2_dlm_lksb *lksb, int status) +{ + struct user_lock_res *lockres = user_lksb_to_lock_res(lksb); + + mlog(ML_BASTS, "UNLOCK AST fired for lockres %.*s, flags 0x%x\n", + lockres->l_namelen, lockres->l_name, lockres->l_flags); + + if (status) + mlog(ML_ERROR, "dlm returns status %d\n", status); + + spin_lock(&lockres->l_lock); + /* The teardown flag gets set early during the unlock process, + * so test the cancel flag to make sure that this ast isn't + * for a concurrent cancel. */ + if (lockres->l_flags & USER_LOCK_IN_TEARDOWN + && !(lockres->l_flags & USER_LOCK_IN_CANCEL)) { + lockres->l_level = DLM_LOCK_IV; + } else if (status == DLM_CANCELGRANT) { + /* 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 */ + lockres->l_requested = DLM_LOCK_IV; /* 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); +} + +/* + * This is the userdlmfs locking protocol version. + * + * See fs/ocfs2/dlmglue.c for more details on locking versions. + */ +static struct ocfs2_locking_protocol user_dlm_lproto = { + .lp_max_version = { + .pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR, + .pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR, + }, + .lp_lock_ast = user_ast, + .lp_blocking_ast = user_bast, + .lp_unlock_ast = user_unlock_ast, +}; + +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(struct work_struct *work) +{ + int new_level, status; + struct user_lock_res *lockres = + container_of(work, struct user_lock_res, l_work); + struct ocfs2_cluster_connection *conn = + cluster_connection_from_user_lockres(lockres); + + mlog(0, "lockres %.*s\n", lockres->l_namelen, 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_namelen, 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(ML_BASTS, "lockres %.*s USER_LOCK_BLOCKED\n", + lockres->l_namelen, lockres->l_name); + spin_unlock(&lockres->l_lock); + goto drop_ref; + } + + if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { + mlog(ML_BASTS, "lockres %.*s USER_LOCK_IN_TEARDOWN\n", + lockres->l_namelen, lockres->l_name); + spin_unlock(&lockres->l_lock); + goto drop_ref; + } + + if (lockres->l_flags & USER_LOCK_BUSY) { + if (lockres->l_flags & USER_LOCK_IN_CANCEL) { + mlog(ML_BASTS, "lockres %.*s USER_LOCK_IN_CANCEL\n", + lockres->l_namelen, lockres->l_name); + spin_unlock(&lockres->l_lock); + goto drop_ref; + } + + lockres->l_flags |= USER_LOCK_IN_CANCEL; + spin_unlock(&lockres->l_lock); + + status = ocfs2_dlm_unlock(conn, &lockres->l_lksb, + DLM_LKF_CANCEL); + if (status) + user_log_dlm_error("ocfs2_dlm_unlock", 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 == DLM_LOCK_EX) + && (lockres->l_ex_holders || lockres->l_ro_holders)) { + spin_unlock(&lockres->l_lock); + mlog(ML_BASTS, "lockres %.*s, EX/PR Holders %u,%u\n", + lockres->l_namelen, lockres->l_name, + lockres->l_ex_holders, lockres->l_ro_holders); + goto drop_ref; + } + + if ((lockres->l_blocking == DLM_LOCK_PR) + && lockres->l_ex_holders) { + spin_unlock(&lockres->l_lock); + mlog(ML_BASTS, "lockres %.*s, EX Holders %u\n", + lockres->l_namelen, lockres->l_name, + 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(ML_BASTS, "lockres %.*s, downconvert %d => %d\n", + lockres->l_namelen, lockres->l_name, lockres->l_level, new_level); + spin_unlock(&lockres->l_lock); + + /* need lock downconvert request now... */ + status = ocfs2_dlm_lock(conn, new_level, &lockres->l_lksb, + DLM_LKF_CONVERT|DLM_LKF_VALBLK, + lockres->l_name, + lockres->l_namelen); + if (status) { + user_log_dlm_error("ocfs2_dlm_lock", 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 DLM_LOCK_EX: + lockres->l_ex_holders++; + break; + case DLM_LOCK_PR: + 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 ocfs2_cluster_connection *conn = + cluster_connection_from_user_lockres(lockres); + + if (level != DLM_LOCK_EX && + level != DLM_LOCK_PR) { + mlog(ML_ERROR, "lockres %.*s: invalid request!\n", + lockres->l_namelen, lockres->l_name); + status = -EINVAL; + goto bail; + } + + mlog(ML_BASTS, "lockres %.*s, level %d, flags = 0x%x\n", + lockres->l_namelen, lockres->l_name, level, lkm_flags); + +again: + if (signal_pending(current)) { + status = -ERESTARTSYS; + goto bail; + } + + spin_lock(&lockres->l_lock); + if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { + spin_unlock(&lockres->l_lock); + status = -EAGAIN; + goto bail; + } + + /* 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 | DLM_LKF_VALBLK; + if (lockres->l_level != DLM_LOCK_IV) + local_flags |= DLM_LKF_CONVERT; + + lockres->l_requested = level; + lockres->l_flags |= USER_LOCK_BUSY; + spin_unlock(&lockres->l_lock); + + BUG_ON(level == DLM_LOCK_IV); + BUG_ON(level == DLM_LOCK_NL); + + /* call dlm_lock to upgrade lock now */ + status = ocfs2_dlm_lock(conn, level, &lockres->l_lksb, + local_flags, lockres->l_name, + lockres->l_namelen); + if (status) { + if ((lkm_flags & DLM_LKF_NOQUEUE) && + (status != -EAGAIN)) + user_log_dlm_error("ocfs2_dlm_lock", + status, lockres); + user_recover_from_dlm_error(lockres); + goto bail; + } + + user_wait_on_busy_lock(lockres); + goto again; + } + + user_dlm_inc_holders(lockres, level); + spin_unlock(&lockres->l_lock); + + status = 0; +bail: + return status; +} + +static inline void user_dlm_dec_holders(struct user_lock_res *lockres, + int level) +{ + switch(level) { + case DLM_LOCK_EX: + BUG_ON(!lockres->l_ex_holders); + lockres->l_ex_holders--; + break; + case DLM_LOCK_PR: + 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 != DLM_LOCK_EX && + level != DLM_LOCK_PR) { + mlog(ML_ERROR, "lockres %.*s: invalid request!\n", + lockres->l_namelen, lockres->l_name); + return; + } + + 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; + + 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_ATTACHED; + 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); +} |