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2e60d7683c
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>
59 lines
1.9 KiB
C
59 lines
1.9 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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#ifndef __SUPER_DOT_H__
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#define __SUPER_DOT_H__
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#include <linux/fs.h>
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#include <linux/dcache.h>
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#include "incore.h"
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extern void gfs2_lm_unmount(struct gfs2_sbd *sdp);
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static inline unsigned int gfs2_jindex_size(struct gfs2_sbd *sdp)
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{
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unsigned int x;
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spin_lock(&sdp->sd_jindex_spin);
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x = sdp->sd_journals;
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spin_unlock(&sdp->sd_jindex_spin);
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return x;
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}
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extern void gfs2_jindex_free(struct gfs2_sbd *sdp);
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extern int gfs2_mount_args(struct gfs2_args *args, char *data);
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extern struct gfs2_jdesc *gfs2_jdesc_find(struct gfs2_sbd *sdp, unsigned int jid);
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extern int gfs2_jdesc_check(struct gfs2_jdesc *jd);
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extern int gfs2_lookup_in_master_dir(struct gfs2_sbd *sdp, char *filename,
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struct gfs2_inode **ipp);
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extern int gfs2_make_fs_rw(struct gfs2_sbd *sdp);
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extern void gfs2_online_uevent(struct gfs2_sbd *sdp);
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extern int gfs2_statfs_init(struct gfs2_sbd *sdp);
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extern void gfs2_statfs_change(struct gfs2_sbd *sdp, s64 total, s64 free,
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s64 dinodes);
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extern void gfs2_statfs_change_in(struct gfs2_statfs_change_host *sc,
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const void *buf);
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extern void update_statfs(struct gfs2_sbd *sdp, struct buffer_head *m_bh,
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struct buffer_head *l_bh);
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extern int gfs2_statfs_sync(struct super_block *sb, int type);
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extern void gfs2_freeze_func(struct work_struct *work);
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extern struct file_system_type gfs2_fs_type;
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extern struct file_system_type gfs2meta_fs_type;
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extern const struct export_operations gfs2_export_ops;
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extern const struct super_operations gfs2_super_ops;
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extern const struct dentry_operations gfs2_dops;
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extern const struct xattr_handler *gfs2_xattr_handlers[];
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#endif /* __SUPER_DOT_H__ */
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