diff options
Diffstat (limited to 'fs/dlm/user.c')
| -rw-r--r-- | fs/dlm/user.c | 1015 |
1 files changed, 1015 insertions, 0 deletions
diff --git a/fs/dlm/user.c b/fs/dlm/user.c new file mode 100644 index 000000000..fb85f32e9 --- /dev/null +++ b/fs/dlm/user.c @@ -0,0 +1,1015 @@ +/* + * Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved. + * + * This copyrighted material is made available to anyone wishing to use, + * modify, copy, or redistribute it subject to the terms and conditions + * of the GNU General Public License v.2. + */ + +#include <linux/miscdevice.h> +#include <linux/init.h> +#include <linux/wait.h> +#include <linux/module.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/poll.h> +#include <linux/signal.h> +#include <linux/spinlock.h> +#include <linux/dlm.h> +#include <linux/dlm_device.h> +#include <linux/slab.h> + +#include "dlm_internal.h" +#include "lockspace.h" +#include "lock.h" +#include "lvb_table.h" +#include "user.h" +#include "ast.h" + +static const char name_prefix[] = "dlm"; +static const struct file_operations device_fops; +static atomic_t dlm_monitor_opened; +static int dlm_monitor_unused = 1; + +#ifdef CONFIG_COMPAT + +struct dlm_lock_params32 { + __u8 mode; + __u8 namelen; + __u16 unused; + __u32 flags; + __u32 lkid; + __u32 parent; + __u64 xid; + __u64 timeout; + __u32 castparam; + __u32 castaddr; + __u32 bastparam; + __u32 bastaddr; + __u32 lksb; + char lvb[DLM_USER_LVB_LEN]; + char name[0]; +}; + +struct dlm_write_request32 { + __u32 version[3]; + __u8 cmd; + __u8 is64bit; + __u8 unused[2]; + + union { + struct dlm_lock_params32 lock; + struct dlm_lspace_params lspace; + struct dlm_purge_params purge; + } i; +}; + +struct dlm_lksb32 { + __u32 sb_status; + __u32 sb_lkid; + __u8 sb_flags; + __u32 sb_lvbptr; +}; + +struct dlm_lock_result32 { + __u32 version[3]; + __u32 length; + __u32 user_astaddr; + __u32 user_astparam; + __u32 user_lksb; + struct dlm_lksb32 lksb; + __u8 bast_mode; + __u8 unused[3]; + /* Offsets may be zero if no data is present */ + __u32 lvb_offset; +}; + +static void compat_input(struct dlm_write_request *kb, + struct dlm_write_request32 *kb32, + int namelen) +{ + kb->version[0] = kb32->version[0]; + kb->version[1] = kb32->version[1]; + kb->version[2] = kb32->version[2]; + + kb->cmd = kb32->cmd; + kb->is64bit = kb32->is64bit; + if (kb->cmd == DLM_USER_CREATE_LOCKSPACE || + kb->cmd == DLM_USER_REMOVE_LOCKSPACE) { + kb->i.lspace.flags = kb32->i.lspace.flags; + kb->i.lspace.minor = kb32->i.lspace.minor; + memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen); + } else if (kb->cmd == DLM_USER_PURGE) { + kb->i.purge.nodeid = kb32->i.purge.nodeid; + kb->i.purge.pid = kb32->i.purge.pid; + } else { + kb->i.lock.mode = kb32->i.lock.mode; + kb->i.lock.namelen = kb32->i.lock.namelen; + kb->i.lock.flags = kb32->i.lock.flags; + kb->i.lock.lkid = kb32->i.lock.lkid; + kb->i.lock.parent = kb32->i.lock.parent; + kb->i.lock.xid = kb32->i.lock.xid; + kb->i.lock.timeout = kb32->i.lock.timeout; + kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam; + kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr; + kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam; + kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr; + kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb; + memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN); + memcpy(kb->i.lock.name, kb32->i.lock.name, namelen); + } +} + +static void compat_output(struct dlm_lock_result *res, + struct dlm_lock_result32 *res32) +{ + res32->version[0] = res->version[0]; + res32->version[1] = res->version[1]; + res32->version[2] = res->version[2]; + + res32->user_astaddr = (__u32)(long)res->user_astaddr; + res32->user_astparam = (__u32)(long)res->user_astparam; + res32->user_lksb = (__u32)(long)res->user_lksb; + res32->bast_mode = res->bast_mode; + + res32->lvb_offset = res->lvb_offset; + res32->length = res->length; + + res32->lksb.sb_status = res->lksb.sb_status; + res32->lksb.sb_flags = res->lksb.sb_flags; + res32->lksb.sb_lkid = res->lksb.sb_lkid; + res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr; +} +#endif + +/* Figure out if this lock is at the end of its life and no longer + available for the application to use. The lkb still exists until + the final ast is read. A lock becomes EOL in three situations: + 1. a noqueue request fails with EAGAIN + 2. an unlock completes with EUNLOCK + 3. a cancel of a waiting request completes with ECANCEL/EDEADLK + An EOL lock needs to be removed from the process's list of locks. + And we can't allow any new operation on an EOL lock. This is + not related to the lifetime of the lkb struct which is managed + entirely by refcount. */ + +static int lkb_is_endoflife(int mode, int status) +{ + switch (status) { + case -DLM_EUNLOCK: + return 1; + case -DLM_ECANCEL: + case -ETIMEDOUT: + case -EDEADLK: + case -EAGAIN: + if (mode == DLM_LOCK_IV) + return 1; + break; + } + return 0; +} + +/* we could possibly check if the cancel of an orphan has resulted in the lkb + being removed and then remove that lkb from the orphans list and free it */ + +void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode, + int status, uint32_t sbflags, uint64_t seq) +{ + struct dlm_ls *ls; + struct dlm_user_args *ua; + struct dlm_user_proc *proc; + int rv; + + if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) + return; + + ls = lkb->lkb_resource->res_ls; + mutex_lock(&ls->ls_clear_proc_locks); + + /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast + can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed + lkb->ua so we can't try to use it. This second check is necessary + for cases where a completion ast is received for an operation that + began before clear_proc_locks did its cancel/unlock. */ + + if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) + goto out; + + DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb);); + ua = lkb->lkb_ua; + proc = ua->proc; + + if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL) + goto out; + + if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status)) + lkb->lkb_flags |= DLM_IFL_ENDOFLIFE; + + spin_lock(&proc->asts_spin); + + rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq); + if (rv < 0) { + spin_unlock(&proc->asts_spin); + goto out; + } + + if (list_empty(&lkb->lkb_cb_list)) { + kref_get(&lkb->lkb_ref); + list_add_tail(&lkb->lkb_cb_list, &proc->asts); + wake_up_interruptible(&proc->wait); + } + spin_unlock(&proc->asts_spin); + + if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) { + /* N.B. spin_lock locks_spin, not asts_spin */ + spin_lock(&proc->locks_spin); + if (!list_empty(&lkb->lkb_ownqueue)) { + list_del_init(&lkb->lkb_ownqueue); + dlm_put_lkb(lkb); + } + spin_unlock(&proc->locks_spin); + } + out: + mutex_unlock(&ls->ls_clear_proc_locks); +} + +static int device_user_lock(struct dlm_user_proc *proc, + struct dlm_lock_params *params) +{ + struct dlm_ls *ls; + struct dlm_user_args *ua; + uint32_t lkid; + int error = -ENOMEM; + + ls = dlm_find_lockspace_local(proc->lockspace); + if (!ls) + return -ENOENT; + + if (!params->castaddr || !params->lksb) { + error = -EINVAL; + goto out; + } + + ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); + if (!ua) + goto out; + ua->proc = proc; + ua->user_lksb = params->lksb; + ua->castparam = params->castparam; + ua->castaddr = params->castaddr; + ua->bastparam = params->bastparam; + ua->bastaddr = params->bastaddr; + ua->xid = params->xid; + + if (params->flags & DLM_LKF_CONVERT) { + error = dlm_user_convert(ls, ua, + params->mode, params->flags, + params->lkid, params->lvb, + (unsigned long) params->timeout); + } else if (params->flags & DLM_LKF_ORPHAN) { + error = dlm_user_adopt_orphan(ls, ua, + params->mode, params->flags, + params->name, params->namelen, + (unsigned long) params->timeout, + &lkid); + if (!error) + error = lkid; + } else { + error = dlm_user_request(ls, ua, + params->mode, params->flags, + params->name, params->namelen, + (unsigned long) params->timeout); + if (!error) + error = ua->lksb.sb_lkid; + } + out: + dlm_put_lockspace(ls); + return error; +} + +static int device_user_unlock(struct dlm_user_proc *proc, + struct dlm_lock_params *params) +{ + struct dlm_ls *ls; + struct dlm_user_args *ua; + int error = -ENOMEM; + + ls = dlm_find_lockspace_local(proc->lockspace); + if (!ls) + return -ENOENT; + + ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); + if (!ua) + goto out; + ua->proc = proc; + ua->user_lksb = params->lksb; + ua->castparam = params->castparam; + ua->castaddr = params->castaddr; + + if (params->flags & DLM_LKF_CANCEL) + error = dlm_user_cancel(ls, ua, params->flags, params->lkid); + else + error = dlm_user_unlock(ls, ua, params->flags, params->lkid, + params->lvb); + out: + dlm_put_lockspace(ls); + return error; +} + +static int device_user_deadlock(struct dlm_user_proc *proc, + struct dlm_lock_params *params) +{ + struct dlm_ls *ls; + int error; + + ls = dlm_find_lockspace_local(proc->lockspace); + if (!ls) + return -ENOENT; + + error = dlm_user_deadlock(ls, params->flags, params->lkid); + + dlm_put_lockspace(ls); + return error; +} + +static int dlm_device_register(struct dlm_ls *ls, char *name) +{ + int error, len; + + /* The device is already registered. This happens when the + lockspace is created multiple times from userspace. */ + if (ls->ls_device.name) + return 0; + + error = -ENOMEM; + len = strlen(name) + strlen(name_prefix) + 2; + ls->ls_device.name = kzalloc(len, GFP_NOFS); + if (!ls->ls_device.name) + goto fail; + + snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, + name); + ls->ls_device.fops = &device_fops; + ls->ls_device.minor = MISC_DYNAMIC_MINOR; + + error = misc_register(&ls->ls_device); + if (error) { + kfree(ls->ls_device.name); + } +fail: + return error; +} + +int dlm_device_deregister(struct dlm_ls *ls) +{ + int error; + + /* The device is not registered. This happens when the lockspace + was never used from userspace, or when device_create_lockspace() + calls dlm_release_lockspace() after the register fails. */ + if (!ls->ls_device.name) + return 0; + + error = misc_deregister(&ls->ls_device); + if (!error) + kfree(ls->ls_device.name); + return error; +} + +static int device_user_purge(struct dlm_user_proc *proc, + struct dlm_purge_params *params) +{ + struct dlm_ls *ls; + int error; + + ls = dlm_find_lockspace_local(proc->lockspace); + if (!ls) + return -ENOENT; + + error = dlm_user_purge(ls, proc, params->nodeid, params->pid); + + dlm_put_lockspace(ls); + return error; +} + +static int device_create_lockspace(struct dlm_lspace_params *params) +{ + dlm_lockspace_t *lockspace; + struct dlm_ls *ls; + int error; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + error = dlm_new_lockspace(params->name, NULL, params->flags, + DLM_USER_LVB_LEN, NULL, NULL, NULL, + &lockspace); + if (error) + return error; + + ls = dlm_find_lockspace_local(lockspace); + if (!ls) + return -ENOENT; + + error = dlm_device_register(ls, params->name); + dlm_put_lockspace(ls); + + if (error) + dlm_release_lockspace(lockspace, 0); + else + error = ls->ls_device.minor; + + return error; +} + +static int device_remove_lockspace(struct dlm_lspace_params *params) +{ + dlm_lockspace_t *lockspace; + struct dlm_ls *ls; + int error, force = 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + ls = dlm_find_lockspace_device(params->minor); + if (!ls) + return -ENOENT; + + if (params->flags & DLM_USER_LSFLG_FORCEFREE) + force = 2; + + lockspace = ls->ls_local_handle; + dlm_put_lockspace(ls); + + /* The final dlm_release_lockspace waits for references to go to + zero, so all processes will need to close their device for the + ls before the release will proceed. release also calls the + device_deregister above. Converting a positive return value + from release to zero means that userspace won't know when its + release was the final one, but it shouldn't need to know. */ + + error = dlm_release_lockspace(lockspace, force); + if (error > 0) + error = 0; + return error; +} + +/* Check the user's version matches ours */ +static int check_version(struct dlm_write_request *req) +{ + if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || + (req->version[0] == DLM_DEVICE_VERSION_MAJOR && + req->version[1] > DLM_DEVICE_VERSION_MINOR)) { + + printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " + "user (%d.%d.%d) kernel (%d.%d.%d)\n", + current->comm, + task_pid_nr(current), + req->version[0], + req->version[1], + req->version[2], + DLM_DEVICE_VERSION_MAJOR, + DLM_DEVICE_VERSION_MINOR, + DLM_DEVICE_VERSION_PATCH); + return -EINVAL; + } + return 0; +} + +/* + * device_write + * + * device_user_lock + * dlm_user_request -> request_lock + * dlm_user_convert -> convert_lock + * + * device_user_unlock + * dlm_user_unlock -> unlock_lock + * dlm_user_cancel -> cancel_lock + * + * device_create_lockspace + * dlm_new_lockspace + * + * device_remove_lockspace + * dlm_release_lockspace + */ + +/* a write to a lockspace device is a lock or unlock request, a write + to the control device is to create/remove a lockspace */ + +static ssize_t device_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct dlm_user_proc *proc = file->private_data; + struct dlm_write_request *kbuf; + int error; + +#ifdef CONFIG_COMPAT + if (count < sizeof(struct dlm_write_request32)) +#else + if (count < sizeof(struct dlm_write_request)) +#endif + return -EINVAL; + + /* + * can't compare against COMPAT/dlm_write_request32 because + * we don't yet know if is64bit is zero + */ + if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) + return -EINVAL; + + kbuf = kzalloc(count + 1, GFP_NOFS); + if (!kbuf) + return -ENOMEM; + + if (copy_from_user(kbuf, buf, count)) { + error = -EFAULT; + goto out_free; + } + + if (check_version(kbuf)) { + error = -EBADE; + goto out_free; + } + +#ifdef CONFIG_COMPAT + if (!kbuf->is64bit) { + struct dlm_write_request32 *k32buf; + int namelen = 0; + + if (count > sizeof(struct dlm_write_request32)) + namelen = count - sizeof(struct dlm_write_request32); + + k32buf = (struct dlm_write_request32 *)kbuf; + + /* add 1 after namelen so that the name string is terminated */ + kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, + GFP_NOFS); + if (!kbuf) { + kfree(k32buf); + return -ENOMEM; + } + + if (proc) + set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); + + compat_input(kbuf, k32buf, namelen); + kfree(k32buf); + } +#endif + + /* do we really need this? can a write happen after a close? */ + if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && + (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { + error = -EINVAL; + goto out_free; + } + + error = -EINVAL; + + switch (kbuf->cmd) + { + case DLM_USER_LOCK: + if (!proc) { + log_print("no locking on control device"); + goto out_free; + } + error = device_user_lock(proc, &kbuf->i.lock); + break; + + case DLM_USER_UNLOCK: + if (!proc) { + log_print("no locking on control device"); + goto out_free; + } + error = device_user_unlock(proc, &kbuf->i.lock); + break; + + case DLM_USER_DEADLOCK: + if (!proc) { + log_print("no locking on control device"); + goto out_free; + } + error = device_user_deadlock(proc, &kbuf->i.lock); + break; + + case DLM_USER_CREATE_LOCKSPACE: + if (proc) { + log_print("create/remove only on control device"); + goto out_free; + } + error = device_create_lockspace(&kbuf->i.lspace); + break; + + case DLM_USER_REMOVE_LOCKSPACE: + if (proc) { + log_print("create/remove only on control device"); + goto out_free; + } + error = device_remove_lockspace(&kbuf->i.lspace); + break; + + case DLM_USER_PURGE: + if (!proc) { + log_print("no locking on control device"); + goto out_free; + } + error = device_user_purge(proc, &kbuf->i.purge); + break; + + default: + log_print("Unknown command passed to DLM device : %d\n", + kbuf->cmd); + } + + out_free: + kfree(kbuf); + return error; +} + +/* Every process that opens the lockspace device has its own "proc" structure + hanging off the open file that's used to keep track of locks owned by the + process and asts that need to be delivered to the process. */ + +static int device_open(struct inode *inode, struct file *file) +{ + struct dlm_user_proc *proc; + struct dlm_ls *ls; + + ls = dlm_find_lockspace_device(iminor(inode)); + if (!ls) + return -ENOENT; + + proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS); + if (!proc) { + dlm_put_lockspace(ls); + return -ENOMEM; + } + + proc->lockspace = ls->ls_local_handle; + INIT_LIST_HEAD(&proc->asts); + INIT_LIST_HEAD(&proc->locks); + INIT_LIST_HEAD(&proc->unlocking); + spin_lock_init(&proc->asts_spin); + spin_lock_init(&proc->locks_spin); + init_waitqueue_head(&proc->wait); + file->private_data = proc; + + return 0; +} + +static int device_close(struct inode *inode, struct file *file) +{ + struct dlm_user_proc *proc = file->private_data; + struct dlm_ls *ls; + + ls = dlm_find_lockspace_local(proc->lockspace); + if (!ls) + return -ENOENT; + + set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); + + dlm_clear_proc_locks(ls, proc); + + /* at this point no more lkb's should exist for this lockspace, + so there's no chance of dlm_user_add_ast() being called and + looking for lkb->ua->proc */ + + kfree(proc); + file->private_data = NULL; + + dlm_put_lockspace(ls); + dlm_put_lockspace(ls); /* for the find in device_open() */ + + /* FIXME: AUTOFREE: if this ls is no longer used do + device_remove_lockspace() */ + + return 0; +} + +static int copy_result_to_user(struct dlm_user_args *ua, int compat, + uint32_t flags, int mode, int copy_lvb, + char __user *buf, size_t count) +{ +#ifdef CONFIG_COMPAT + struct dlm_lock_result32 result32; +#endif + struct dlm_lock_result result; + void *resultptr; + int error=0; + int len; + int struct_len; + + memset(&result, 0, sizeof(struct dlm_lock_result)); + result.version[0] = DLM_DEVICE_VERSION_MAJOR; + result.version[1] = DLM_DEVICE_VERSION_MINOR; + result.version[2] = DLM_DEVICE_VERSION_PATCH; + memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); + result.user_lksb = ua->user_lksb; + + /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated + in a conversion unless the conversion is successful. See code + in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, + notes that a new blocking AST address and parameter are set even if + the conversion fails, so maybe we should just do that. */ + + if (flags & DLM_CB_BAST) { + result.user_astaddr = ua->bastaddr; + result.user_astparam = ua->bastparam; + result.bast_mode = mode; + } else { + result.user_astaddr = ua->castaddr; + result.user_astparam = ua->castparam; + } + +#ifdef CONFIG_COMPAT + if (compat) + len = sizeof(struct dlm_lock_result32); + else +#endif + len = sizeof(struct dlm_lock_result); + struct_len = len; + + /* copy lvb to userspace if there is one, it's been updated, and + the user buffer has space for it */ + + if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { + if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, + DLM_USER_LVB_LEN)) { + error = -EFAULT; + goto out; + } + + result.lvb_offset = len; + len += DLM_USER_LVB_LEN; + } + + result.length = len; + resultptr = &result; +#ifdef CONFIG_COMPAT + if (compat) { + compat_output(&result, &result32); + resultptr = &result32; + } +#endif + + if (copy_to_user(buf, resultptr, struct_len)) + error = -EFAULT; + else + error = len; + out: + return error; +} + +static int copy_version_to_user(char __user *buf, size_t count) +{ + struct dlm_device_version ver; + + memset(&ver, 0, sizeof(struct dlm_device_version)); + ver.version[0] = DLM_DEVICE_VERSION_MAJOR; + ver.version[1] = DLM_DEVICE_VERSION_MINOR; + ver.version[2] = DLM_DEVICE_VERSION_PATCH; + + if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) + return -EFAULT; + return sizeof(struct dlm_device_version); +} + +/* a read returns a single ast described in a struct dlm_lock_result */ + +static ssize_t device_read(struct file *file, char __user *buf, size_t count, + loff_t *ppos) +{ + struct dlm_user_proc *proc = file->private_data; + struct dlm_lkb *lkb; + DECLARE_WAITQUEUE(wait, current); + struct dlm_callback cb; + int rv, resid, copy_lvb = 0; + + if (count == sizeof(struct dlm_device_version)) { + rv = copy_version_to_user(buf, count); + return rv; + } + + if (!proc) { + log_print("non-version read from control device %zu", count); + return -EINVAL; + } + +#ifdef CONFIG_COMPAT + if (count < sizeof(struct dlm_lock_result32)) +#else + if (count < sizeof(struct dlm_lock_result)) +#endif + return -EINVAL; + + try_another: + + /* do we really need this? can a read happen after a close? */ + if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) + return -EINVAL; + + spin_lock(&proc->asts_spin); + if (list_empty(&proc->asts)) { + if (file->f_flags & O_NONBLOCK) { + spin_unlock(&proc->asts_spin); + return -EAGAIN; + } + + add_wait_queue(&proc->wait, &wait); + + repeat: + set_current_state(TASK_INTERRUPTIBLE); + if (list_empty(&proc->asts) && !signal_pending(current)) { + spin_unlock(&proc->asts_spin); + schedule(); + spin_lock(&proc->asts_spin); + goto repeat; + } + set_current_state(TASK_RUNNING); + remove_wait_queue(&proc->wait, &wait); + + if (signal_pending(current)) { + spin_unlock(&proc->asts_spin); + return -ERESTARTSYS; + } + } + + /* if we empty lkb_callbacks, we don't want to unlock the spinlock + without removing lkb_cb_list; so empty lkb_cb_list is always + consistent with empty lkb_callbacks */ + + lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); + + rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); + if (rv < 0) { + /* this shouldn't happen; lkb should have been removed from + list when resid was zero */ + log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); + list_del_init(&lkb->lkb_cb_list); + spin_unlock(&proc->asts_spin); + /* removes ref for proc->asts, may cause lkb to be freed */ + dlm_put_lkb(lkb); + goto try_another; + } + if (!resid) + list_del_init(&lkb->lkb_cb_list); + spin_unlock(&proc->asts_spin); + + if (cb.flags & DLM_CB_SKIP) { + /* removes ref for proc->asts, may cause lkb to be freed */ + if (!resid) + dlm_put_lkb(lkb); + goto try_another; + } + + if (cb.flags & DLM_CB_CAST) { + int old_mode, new_mode; + + old_mode = lkb->lkb_last_cast.mode; + new_mode = cb.mode; + + if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && + dlm_lvb_operations[old_mode + 1][new_mode + 1]) + copy_lvb = 1; + + lkb->lkb_lksb->sb_status = cb.sb_status; + lkb->lkb_lksb->sb_flags = cb.sb_flags; + } + + rv = copy_result_to_user(lkb->lkb_ua, + test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), + cb.flags, cb.mode, copy_lvb, buf, count); + + /* removes ref for proc->asts, may cause lkb to be freed */ + if (!resid) + dlm_put_lkb(lkb); + + return rv; +} + +static unsigned int device_poll(struct file *file, poll_table *wait) +{ + struct dlm_user_proc *proc = file->private_data; + + poll_wait(file, &proc->wait, wait); + + spin_lock(&proc->asts_spin); + if (!list_empty(&proc->asts)) { + spin_unlock(&proc->asts_spin); + return POLLIN | POLLRDNORM; + } + spin_unlock(&proc->asts_spin); + return 0; +} + +int dlm_user_daemon_available(void) +{ + /* dlm_controld hasn't started (or, has started, but not + properly populated configfs) */ + + if (!dlm_our_nodeid()) + return 0; + + /* This is to deal with versions of dlm_controld that don't + know about the monitor device. We assume that if the + dlm_controld was started (above), but the monitor device + was never opened, that it's an old version. dlm_controld + should open the monitor device before populating configfs. */ + + if (dlm_monitor_unused) + return 1; + + return atomic_read(&dlm_monitor_opened) ? 1 : 0; +} + +static int ctl_device_open(struct inode *inode, struct file *file) +{ + file->private_data = NULL; + return 0; +} + +static int ctl_device_close(struct inode *inode, struct file *file) +{ + return 0; +} + +static int monitor_device_open(struct inode *inode, struct file *file) +{ + atomic_inc(&dlm_monitor_opened); + dlm_monitor_unused = 0; + return 0; +} + +static int monitor_device_close(struct inode *inode, struct file *file) +{ + if (atomic_dec_and_test(&dlm_monitor_opened)) + dlm_stop_lockspaces(); + return 0; +} + +static const struct file_operations device_fops = { + .open = device_open, + .release = device_close, + .read = device_read, + .write = device_write, + .poll = device_poll, + .owner = THIS_MODULE, + .llseek = noop_llseek, +}; + +static const struct file_operations ctl_device_fops = { + .open = ctl_device_open, + .release = ctl_device_close, + .read = device_read, + .write = device_write, + .owner = THIS_MODULE, + .llseek = noop_llseek, +}; + +static struct miscdevice ctl_device = { + .name = "dlm-control", + .fops = &ctl_device_fops, + .minor = MISC_DYNAMIC_MINOR, +}; + +static const struct file_operations monitor_device_fops = { + .open = monitor_device_open, + .release = monitor_device_close, + .owner = THIS_MODULE, + .llseek = noop_llseek, +}; + +static struct miscdevice monitor_device = { + .name = "dlm-monitor", + .fops = &monitor_device_fops, + .minor = MISC_DYNAMIC_MINOR, +}; + +int __init dlm_user_init(void) +{ + int error; + + atomic_set(&dlm_monitor_opened, 0); + + error = misc_register(&ctl_device); + if (error) { + log_print("misc_register failed for control device"); + goto out; + } + + error = misc_register(&monitor_device); + if (error) { + log_print("misc_register failed for monitor device"); + misc_deregister(&ctl_device); + } + out: + return error; +} + +void dlm_user_exit(void) +{ + misc_deregister(&ctl_device); + misc_deregister(&monitor_device); +} + |