From 0f8e0d9a317406612700426fad3efab0b7bbc467 Mon Sep 17 00:00:00 2001 From: David Teigland Date: Wed, 6 Aug 2008 13:30:24 -0500 Subject: dlm: allow multiple lockspace creates Add a count for lockspace create and release so that create can be called multiple times to use the lockspace from different places. Also add the new flag DLM_LSFL_NEWEXCL to create a lockspace with the previous behavior of returning -EEXIST if the lockspace already exists. Signed-off-by: David Teigland --- fs/dlm/dlm_internal.h | 6 ++- fs/dlm/lockspace.c | 107 +++++++++++++++++++++++++++++++++----------------- fs/dlm/user.c | 54 +++++++++++++++---------- fs/dlm/user.h | 3 +- 4 files changed, 109 insertions(+), 61 deletions(-) (limited to 'fs/dlm') diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h index 5a7ac33b629..9e0622aff49 100644 --- a/fs/dlm/dlm_internal.h +++ b/fs/dlm/dlm_internal.h @@ -2,7 +2,7 @@ ******************************************************************************* ** ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. -** Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved. +** Copyright (C) 2004-2008 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 @@ -441,7 +441,9 @@ struct dlm_ls { uint32_t ls_global_id; /* global unique lockspace ID */ uint32_t ls_exflags; int ls_lvblen; - int ls_count; /* reference count */ + int ls_count; /* refcount of processes in + the dlm using this ls */ + int ls_create_count; /* create/release refcount */ unsigned long ls_flags; /* LSFL_ */ struct kobject ls_kobj; diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c index 499e16759e9..56eae4e4a95 100644 --- a/fs/dlm/lockspace.c +++ b/fs/dlm/lockspace.c @@ -2,7 +2,7 @@ ******************************************************************************* ** ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. -** Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved. +** Copyright (C) 2004-2008 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 @@ -23,6 +23,7 @@ #include "lock.h" #include "recover.h" #include "requestqueue.h" +#include "user.h" static int ls_count; static struct mutex ls_lock; @@ -246,23 +247,6 @@ static void dlm_scand_stop(void) kthread_stop(scand_task); } -static struct dlm_ls *dlm_find_lockspace_name(char *name, int namelen) -{ - struct dlm_ls *ls; - - spin_lock(&lslist_lock); - - list_for_each_entry(ls, &lslist, ls_list) { - if (ls->ls_namelen == namelen && - memcmp(ls->ls_name, name, namelen) == 0) - goto out; - } - ls = NULL; - out: - spin_unlock(&lslist_lock); - return ls; -} - struct dlm_ls *dlm_find_lockspace_global(uint32_t id) { struct dlm_ls *ls; @@ -327,6 +311,7 @@ static void remove_lockspace(struct dlm_ls *ls) for (;;) { spin_lock(&lslist_lock); if (ls->ls_count == 0) { + WARN_ON(ls->ls_create_count != 0); list_del(&ls->ls_list); spin_unlock(&lslist_lock); return; @@ -381,7 +366,7 @@ static int new_lockspace(char *name, int namelen, void **lockspace, uint32_t flags, int lvblen) { struct dlm_ls *ls; - int i, size, error = -ENOMEM; + int i, size, error; int do_unreg = 0; if (namelen > DLM_LOCKSPACE_LEN) @@ -393,12 +378,32 @@ static int new_lockspace(char *name, int namelen, void **lockspace, if (!try_module_get(THIS_MODULE)) return -EINVAL; - ls = dlm_find_lockspace_name(name, namelen); - if (ls) { - *lockspace = ls; + error = 0; + + spin_lock(&lslist_lock); + list_for_each_entry(ls, &lslist, ls_list) { + WARN_ON(ls->ls_create_count <= 0); + if (ls->ls_namelen != namelen) + continue; + if (memcmp(ls->ls_name, name, namelen)) + continue; + if (flags & DLM_LSFL_NEWEXCL) { + error = -EEXIST; + break; + } + ls->ls_create_count++; module_put(THIS_MODULE); - return -EEXIST; + error = 1; /* not an error, return 0 */ + break; } + spin_unlock(&lslist_lock); + + if (error < 0) + goto out; + if (error) + goto ret_zero; + + error = -ENOMEM; ls = kzalloc(sizeof(struct dlm_ls) + namelen, GFP_KERNEL); if (!ls) @@ -418,8 +423,9 @@ static int new_lockspace(char *name, int namelen, void **lockspace, ls->ls_allocation = GFP_KERNEL; /* ls_exflags are forced to match among nodes, and we don't - need to require all nodes to have TIMEWARN or FS set */ - ls->ls_exflags = (flags & ~(DLM_LSFL_TIMEWARN | DLM_LSFL_FS)); + need to require all nodes to have some flags set */ + ls->ls_exflags = (flags & ~(DLM_LSFL_TIMEWARN | DLM_LSFL_FS | + DLM_LSFL_NEWEXCL)); size = dlm_config.ci_rsbtbl_size; ls->ls_rsbtbl_size = size; @@ -510,6 +516,7 @@ static int new_lockspace(char *name, int namelen, void **lockspace, down_write(&ls->ls_in_recovery); spin_lock(&lslist_lock); + ls->ls_create_count = 1; list_add(&ls->ls_list, &lslist); spin_unlock(&lslist_lock); @@ -548,7 +555,7 @@ static int new_lockspace(char *name, int namelen, void **lockspace, dlm_create_debug_file(ls); log_debug(ls, "join complete"); - + ret_zero: *lockspace = ls; return 0; @@ -635,11 +642,32 @@ static int release_lockspace(struct dlm_ls *ls, int force) struct dlm_lkb *lkb; struct dlm_rsb *rsb; struct list_head *head; - int i; - int busy = lockspace_busy(ls); + int i, busy, rv; + + busy = lockspace_busy(ls); + + spin_lock(&lslist_lock); + if (ls->ls_create_count == 1) { + if (busy > force) + rv = -EBUSY; + else { + /* remove_lockspace takes ls off lslist */ + ls->ls_create_count = 0; + rv = 0; + } + } else if (ls->ls_create_count > 1) { + rv = --ls->ls_create_count; + } else { + rv = -EINVAL; + } + spin_unlock(&lslist_lock); + + if (rv) { + log_debug(ls, "release_lockspace no remove %d", rv); + return rv; + } - if (busy > force) - return -EBUSY; + dlm_device_deregister(ls); if (force < 3) do_uevent(ls, 0); @@ -720,15 +748,10 @@ static int release_lockspace(struct dlm_ls *ls, int force) dlm_clear_members(ls); dlm_clear_members_gone(ls); kfree(ls->ls_node_array); + log_debug(ls, "release_lockspace final free"); kobject_put(&ls->ls_kobj); /* The ls structure will be freed when the kobject is done with */ - mutex_lock(&ls_lock); - ls_count--; - if (!ls_count) - threads_stop(); - mutex_unlock(&ls_lock); - module_put(THIS_MODULE); return 0; } @@ -750,11 +773,21 @@ static int release_lockspace(struct dlm_ls *ls, int force) int dlm_release_lockspace(void *lockspace, int force) { struct dlm_ls *ls; + int error; ls = dlm_find_lockspace_local(lockspace); if (!ls) return -EINVAL; dlm_put_lockspace(ls); - return release_lockspace(ls, force); + + mutex_lock(&ls_lock); + error = release_lockspace(ls, force); + if (!error) + ls_count--; + else if (!ls_count) + threads_stop(); + mutex_unlock(&ls_lock); + + return error; } diff --git a/fs/dlm/user.c b/fs/dlm/user.c index 34f14a14fb4..6542110c0da 100644 --- a/fs/dlm/user.c +++ b/fs/dlm/user.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2006-2007 Red Hat, Inc. All rights reserved. + * Copyright (C) 2006-2008 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 @@ -340,10 +340,15 @@ static int device_user_deadlock(struct dlm_user_proc *proc, return error; } -static int create_misc_device(struct dlm_ls *ls, char *name) +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_KERNEL); @@ -363,6 +368,22 @@ 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) { @@ -397,7 +418,7 @@ static int device_create_lockspace(struct dlm_lspace_params *params) if (!ls) return -ENOENT; - error = create_misc_device(ls, params->name); + error = dlm_device_register(ls, params->name); dlm_put_lockspace(ls); if (error) @@ -421,31 +442,22 @@ static int device_remove_lockspace(struct dlm_lspace_params *params) if (!ls) return -ENOENT; - /* Deregister the misc device first, so we don't have - * a device that's not attached to a lockspace. If - * dlm_release_lockspace fails then we can recreate it - */ - error = misc_deregister(&ls->ls_device); - if (error) { - dlm_put_lockspace(ls); - goto out; - } - kfree(ls->ls_device.name); - if (params->flags & DLM_USER_LSFLG_FORCEFREE) force = 2; lockspace = ls->ls_local_handle; + dlm_put_lockspace(ls); - /* 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 procede */ + /* 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. */ - dlm_put_lockspace(ls); error = dlm_release_lockspace(lockspace, force); - if (error) - create_misc_device(ls, ls->ls_name); - out: + if (error > 0) + error = 0; return error; } diff --git a/fs/dlm/user.h b/fs/dlm/user.h index d38e9f3e415..c528b6b2991 100644 --- a/fs/dlm/user.h +++ b/fs/dlm/user.h @@ -1,5 +1,5 @@ /* - * Copyright (C) 2006 Red Hat, Inc. All rights reserved. + * Copyright (C) 2006-2008 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 @@ -12,5 +12,6 @@ void dlm_user_add_ast(struct dlm_lkb *lkb, int type); int dlm_user_init(void); void dlm_user_exit(void); +int dlm_device_deregister(struct dlm_ls *ls); #endif -- cgit v1.2.3