mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 11:06:40 +07:00
fc0e38dae6
This patch fixes a race in deallocating glocks which was introduced in the RCU glock patch. We need to ensure that the glock count is kept correct even in the case that there is a race to add a new glock into the hash table. Also, to avoid having to wait for an RCU grace period, the glock counter can be decremented before call_rcu() is called. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
236 lines
5.0 KiB
C
236 lines
5.0 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2009 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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#include <linux/fs.h>
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#include <linux/dlm.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/gfs2_ondisk.h>
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#include "incore.h"
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#include "glock.h"
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#include "util.h"
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static void gdlm_ast(void *arg)
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{
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struct gfs2_glock *gl = arg;
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unsigned ret = gl->gl_state;
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BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
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if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
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memset(gl->gl_lvb, 0, GDLM_LVB_SIZE);
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switch (gl->gl_lksb.sb_status) {
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case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
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gfs2_glock_free(gl);
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return;
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case -DLM_ECANCEL: /* Cancel while getting lock */
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ret |= LM_OUT_CANCELED;
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goto out;
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case -EAGAIN: /* Try lock fails */
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case -EDEADLK: /* Deadlock detected */
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goto out;
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case -ETIMEDOUT: /* Canceled due to timeout */
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ret |= LM_OUT_ERROR;
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goto out;
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case 0: /* Success */
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break;
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default: /* Something unexpected */
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BUG();
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}
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ret = gl->gl_req;
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if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
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if (gl->gl_req == LM_ST_SHARED)
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ret = LM_ST_DEFERRED;
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else if (gl->gl_req == LM_ST_DEFERRED)
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ret = LM_ST_SHARED;
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else
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BUG();
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}
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set_bit(GLF_INITIAL, &gl->gl_flags);
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gfs2_glock_complete(gl, ret);
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return;
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out:
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if (!test_bit(GLF_INITIAL, &gl->gl_flags))
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gl->gl_lksb.sb_lkid = 0;
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gfs2_glock_complete(gl, ret);
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}
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static void gdlm_bast(void *arg, int mode)
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{
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struct gfs2_glock *gl = arg;
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switch (mode) {
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case DLM_LOCK_EX:
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gfs2_glock_cb(gl, LM_ST_UNLOCKED);
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break;
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case DLM_LOCK_CW:
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gfs2_glock_cb(gl, LM_ST_DEFERRED);
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break;
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case DLM_LOCK_PR:
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gfs2_glock_cb(gl, LM_ST_SHARED);
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break;
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default:
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printk(KERN_ERR "unknown bast mode %d", mode);
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BUG();
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}
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}
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/* convert gfs lock-state to dlm lock-mode */
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static int make_mode(const unsigned int lmstate)
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{
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switch (lmstate) {
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case LM_ST_UNLOCKED:
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return DLM_LOCK_NL;
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case LM_ST_EXCLUSIVE:
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return DLM_LOCK_EX;
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case LM_ST_DEFERRED:
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return DLM_LOCK_CW;
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case LM_ST_SHARED:
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return DLM_LOCK_PR;
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}
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printk(KERN_ERR "unknown LM state %d", lmstate);
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BUG();
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return -1;
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}
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static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
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const int req)
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{
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u32 lkf = 0;
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if (gfs_flags & LM_FLAG_TRY)
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lkf |= DLM_LKF_NOQUEUE;
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if (gfs_flags & LM_FLAG_TRY_1CB) {
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lkf |= DLM_LKF_NOQUEUE;
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lkf |= DLM_LKF_NOQUEUEBAST;
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}
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if (gfs_flags & LM_FLAG_PRIORITY) {
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lkf |= DLM_LKF_NOORDER;
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lkf |= DLM_LKF_HEADQUE;
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}
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if (gfs_flags & LM_FLAG_ANY) {
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if (req == DLM_LOCK_PR)
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lkf |= DLM_LKF_ALTCW;
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else if (req == DLM_LOCK_CW)
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lkf |= DLM_LKF_ALTPR;
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else
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BUG();
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}
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if (lkid != 0)
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lkf |= DLM_LKF_CONVERT;
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lkf |= DLM_LKF_VALBLK;
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return lkf;
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}
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static int gdlm_lock(struct gfs2_glock *gl, unsigned int req_state,
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unsigned int flags)
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{
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struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
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int req;
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u32 lkf;
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req = make_mode(req_state);
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lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
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/*
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* Submit the actual lock request.
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*/
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return dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, gl->gl_strname,
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GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
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}
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static void gdlm_put_lock(struct gfs2_glock *gl)
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{
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struct gfs2_sbd *sdp = gl->gl_sbd;
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struct lm_lockstruct *ls = &sdp->sd_lockstruct;
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int error;
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if (gl->gl_lksb.sb_lkid == 0) {
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gfs2_glock_free(gl);
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return;
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}
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error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
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NULL, gl);
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if (error) {
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printk(KERN_ERR "gdlm_unlock %x,%llx err=%d\n",
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gl->gl_name.ln_type,
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(unsigned long long)gl->gl_name.ln_number, error);
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return;
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}
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}
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static void gdlm_cancel(struct gfs2_glock *gl)
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{
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struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
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dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_CANCEL, NULL, gl);
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}
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static int gdlm_mount(struct gfs2_sbd *sdp, const char *fsname)
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{
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struct lm_lockstruct *ls = &sdp->sd_lockstruct;
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int error;
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if (fsname == NULL) {
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fs_info(sdp, "no fsname found\n");
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return -EINVAL;
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}
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error = dlm_new_lockspace(fsname, strlen(fsname), &ls->ls_dlm,
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DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
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(ls->ls_nodir ? DLM_LSFL_NODIR : 0),
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GDLM_LVB_SIZE);
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if (error)
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printk(KERN_ERR "dlm_new_lockspace error %d", error);
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return error;
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}
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static void gdlm_unmount(struct gfs2_sbd *sdp)
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{
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struct lm_lockstruct *ls = &sdp->sd_lockstruct;
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if (ls->ls_dlm) {
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dlm_release_lockspace(ls->ls_dlm, 2);
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ls->ls_dlm = NULL;
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}
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}
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static const match_table_t dlm_tokens = {
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{ Opt_jid, "jid=%d"},
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{ Opt_id, "id=%d"},
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{ Opt_first, "first=%d"},
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{ Opt_nodir, "nodir=%d"},
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{ Opt_err, NULL },
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};
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const struct lm_lockops gfs2_dlm_ops = {
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.lm_proto_name = "lock_dlm",
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.lm_mount = gdlm_mount,
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.lm_unmount = gdlm_unmount,
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.lm_put_lock = gdlm_put_lock,
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.lm_lock = gdlm_lock,
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.lm_cancel = gdlm_cancel,
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.lm_tokens = &dlm_tokens,
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};
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