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![Benjamin Marzinski](/assets/img/avatar_default.png)
The current gfs2 freezing code is considerably more complicated than it should be because it doesn't use the vfs freezing code on any node except the one that begins the freeze. This is because it needs to acquire a cluster glock before calling the vfs code to prevent a deadlock, and without the new freeze_super and thaw_super hooks, that was impossible. To deal with the issue, gfs2 had to do some hacky locking tricks to make sure that a frozen node couldn't be holding on a lock it needed to do the unfreeze ioctl. This patch makes use of the new hooks to simply the gfs2 locking code. Now, all the nodes in the cluster freeze and thaw in exactly the same way. Every node in the cluster caches the freeze glock in the shared state. The new freeze_super hook allows the freezing node to grab this freeze glock in the exclusive state without first calling the vfs freeze_super function. All the nodes in the cluster see this lock change, and call the vfs freeze_super function. The vfs locking code guarantees that the nodes can't get stuck holding the glocks necessary to unfreeze the system. To unfreeze, the freezing node uses the new thaw_super hook to drop the freeze glock. Again, all the nodes notice this, reacquire the glock in shared mode and call the vfs thaw_super function. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
258 lines
5.8 KiB
C
258 lines
5.8 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/buffer_head.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/gfs2_ondisk.h>
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#include <linux/rcupdate.h>
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#include <linux/rculist_bl.h>
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#include <linux/atomic.h>
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#include <linux/mempool.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "super.h"
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#include "sys.h"
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#include "util.h"
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#include "glock.h"
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#include "quota.h"
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#include "recovery.h"
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#include "dir.h"
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#include "glops.h"
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struct workqueue_struct *gfs2_control_wq;
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static void gfs2_init_inode_once(void *foo)
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{
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struct gfs2_inode *ip = foo;
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inode_init_once(&ip->i_inode);
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init_rwsem(&ip->i_rw_mutex);
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INIT_LIST_HEAD(&ip->i_trunc_list);
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ip->i_res = NULL;
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ip->i_hash_cache = NULL;
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}
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static void gfs2_init_glock_once(void *foo)
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{
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struct gfs2_glock *gl = foo;
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INIT_HLIST_BL_NODE(&gl->gl_list);
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spin_lock_init(&gl->gl_spin);
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INIT_LIST_HEAD(&gl->gl_holders);
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INIT_LIST_HEAD(&gl->gl_lru);
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INIT_LIST_HEAD(&gl->gl_ail_list);
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atomic_set(&gl->gl_ail_count, 0);
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atomic_set(&gl->gl_revokes, 0);
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}
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static void gfs2_init_gl_aspace_once(void *foo)
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{
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struct gfs2_glock *gl = foo;
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struct address_space *mapping = (struct address_space *)(gl + 1);
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gfs2_init_glock_once(gl);
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address_space_init_once(mapping);
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}
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/**
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* init_gfs2_fs - Register GFS2 as a filesystem
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*
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* Returns: 0 on success, error code on failure
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*/
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static int __init init_gfs2_fs(void)
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{
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int error;
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gfs2_str2qstr(&gfs2_qdot, ".");
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gfs2_str2qstr(&gfs2_qdotdot, "..");
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gfs2_quota_hash_init();
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error = gfs2_sys_init();
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if (error)
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return error;
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error = list_lru_init(&gfs2_qd_lru);
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if (error)
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goto fail_lru;
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error = gfs2_glock_init();
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if (error)
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goto fail;
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error = -ENOMEM;
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gfs2_glock_cachep = kmem_cache_create("gfs2_glock",
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sizeof(struct gfs2_glock),
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0, 0,
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gfs2_init_glock_once);
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if (!gfs2_glock_cachep)
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goto fail;
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gfs2_glock_aspace_cachep = kmem_cache_create("gfs2_glock(aspace)",
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sizeof(struct gfs2_glock) +
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sizeof(struct address_space),
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0, 0, gfs2_init_gl_aspace_once);
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if (!gfs2_glock_aspace_cachep)
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goto fail;
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gfs2_inode_cachep = kmem_cache_create("gfs2_inode",
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sizeof(struct gfs2_inode),
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0, SLAB_RECLAIM_ACCOUNT|
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SLAB_MEM_SPREAD,
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gfs2_init_inode_once);
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if (!gfs2_inode_cachep)
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goto fail;
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gfs2_bufdata_cachep = kmem_cache_create("gfs2_bufdata",
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sizeof(struct gfs2_bufdata),
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0, 0, NULL);
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if (!gfs2_bufdata_cachep)
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goto fail;
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gfs2_rgrpd_cachep = kmem_cache_create("gfs2_rgrpd",
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sizeof(struct gfs2_rgrpd),
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0, 0, NULL);
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if (!gfs2_rgrpd_cachep)
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goto fail;
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gfs2_quotad_cachep = kmem_cache_create("gfs2_quotad",
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sizeof(struct gfs2_quota_data),
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0, 0, NULL);
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if (!gfs2_quotad_cachep)
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goto fail;
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gfs2_rsrv_cachep = kmem_cache_create("gfs2_mblk",
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sizeof(struct gfs2_blkreserv),
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0, 0, NULL);
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if (!gfs2_rsrv_cachep)
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goto fail;
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register_shrinker(&gfs2_qd_shrinker);
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error = register_filesystem(&gfs2_fs_type);
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if (error)
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goto fail;
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error = register_filesystem(&gfs2meta_fs_type);
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if (error)
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goto fail_unregister;
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error = -ENOMEM;
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gfs_recovery_wq = alloc_workqueue("gfs_recovery",
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WQ_MEM_RECLAIM | WQ_FREEZABLE, 0);
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if (!gfs_recovery_wq)
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goto fail_wq;
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gfs2_control_wq = alloc_workqueue("gfs2_control",
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WQ_UNBOUND | WQ_FREEZABLE, 0);
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if (!gfs2_control_wq)
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goto fail_recovery;
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gfs2_freeze_wq = alloc_workqueue("freeze_workqueue", 0, 0);
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if (!gfs2_freeze_wq)
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goto fail_control;
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gfs2_page_pool = mempool_create_page_pool(64, 0);
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if (!gfs2_page_pool)
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goto fail_freeze;
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gfs2_register_debugfs();
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pr_info("GFS2 installed\n");
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return 0;
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fail_freeze:
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destroy_workqueue(gfs2_freeze_wq);
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fail_control:
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destroy_workqueue(gfs2_control_wq);
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fail_recovery:
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destroy_workqueue(gfs_recovery_wq);
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fail_wq:
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unregister_filesystem(&gfs2meta_fs_type);
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fail_unregister:
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unregister_filesystem(&gfs2_fs_type);
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fail:
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list_lru_destroy(&gfs2_qd_lru);
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fail_lru:
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unregister_shrinker(&gfs2_qd_shrinker);
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gfs2_glock_exit();
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if (gfs2_rsrv_cachep)
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kmem_cache_destroy(gfs2_rsrv_cachep);
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if (gfs2_quotad_cachep)
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kmem_cache_destroy(gfs2_quotad_cachep);
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if (gfs2_rgrpd_cachep)
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kmem_cache_destroy(gfs2_rgrpd_cachep);
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if (gfs2_bufdata_cachep)
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kmem_cache_destroy(gfs2_bufdata_cachep);
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if (gfs2_inode_cachep)
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kmem_cache_destroy(gfs2_inode_cachep);
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if (gfs2_glock_aspace_cachep)
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kmem_cache_destroy(gfs2_glock_aspace_cachep);
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if (gfs2_glock_cachep)
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kmem_cache_destroy(gfs2_glock_cachep);
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gfs2_sys_uninit();
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return error;
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}
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/**
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* exit_gfs2_fs - Unregister the file system
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*
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*/
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static void __exit exit_gfs2_fs(void)
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{
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unregister_shrinker(&gfs2_qd_shrinker);
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gfs2_glock_exit();
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gfs2_unregister_debugfs();
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unregister_filesystem(&gfs2_fs_type);
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unregister_filesystem(&gfs2meta_fs_type);
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destroy_workqueue(gfs_recovery_wq);
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destroy_workqueue(gfs2_control_wq);
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destroy_workqueue(gfs2_freeze_wq);
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list_lru_destroy(&gfs2_qd_lru);
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rcu_barrier();
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mempool_destroy(gfs2_page_pool);
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kmem_cache_destroy(gfs2_rsrv_cachep);
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kmem_cache_destroy(gfs2_quotad_cachep);
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kmem_cache_destroy(gfs2_rgrpd_cachep);
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kmem_cache_destroy(gfs2_bufdata_cachep);
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kmem_cache_destroy(gfs2_inode_cachep);
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kmem_cache_destroy(gfs2_glock_aspace_cachep);
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kmem_cache_destroy(gfs2_glock_cachep);
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gfs2_sys_uninit();
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}
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MODULE_DESCRIPTION("Global File System");
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MODULE_AUTHOR("Red Hat, Inc.");
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MODULE_LICENSE("GPL");
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module_init(init_gfs2_fs);
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module_exit(exit_gfs2_fs);
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