LXR linux/fs/gfs2/glock.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   4 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   5 */
   6
   7#ifndef __GLOCK_DOT_H__
   8#define __GLOCK_DOT_H__
   9
  10#include <linux/sched.h>
  11#include <linux/parser.h>
  12#include "incore.h"
  13#include "util.h"
  14
  15/* Options for hostdata parser */
  16
  17enum {
  18        Opt_jid,
  19        Opt_id,
  20        Opt_first,
  21        Opt_nodir,
  22        Opt_err,
  23};
  24
  25/*
  26 * lm_lockname types
  27 */
  28
  29#define LM_TYPE_RESERVED        0x00
  30#define LM_TYPE_NONDISK         0x01
  31#define LM_TYPE_INODE           0x02
  32#define LM_TYPE_RGRP            0x03
  33#define LM_TYPE_META            0x04
  34#define LM_TYPE_IOPEN           0x05
  35#define LM_TYPE_FLOCK           0x06
  36#define LM_TYPE_PLOCK           0x07
  37#define LM_TYPE_QUOTA           0x08
  38#define LM_TYPE_JOURNAL         0x09
  39
  40/*
  41 * lm_lock() states
  42 *
  43 * SHARED is compatible with SHARED, not with DEFERRED or EX.
  44 * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
  45 */
  46
  47#define LM_ST_UNLOCKED          0
  48#define LM_ST_EXCLUSIVE         1
  49#define LM_ST_DEFERRED          2
  50#define LM_ST_SHARED            3
  51
  52/*
  53 * lm_lock() flags
  54 *
  55 * LM_FLAG_TRY
  56 * Don't wait to acquire the lock if it can't be granted immediately.
  57 *
  58 * LM_FLAG_TRY_1CB
  59 * Send one blocking callback if TRY is set and the lock is not granted.
  60 *
  61 * LM_FLAG_NOEXP
  62 * GFS sets this flag on lock requests it makes while doing journal recovery.
  63 * These special requests should not be blocked due to the recovery like
  64 * ordinary locks would be.
  65 *
  66 * LM_FLAG_ANY
  67 * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
  68 * also be granted in SHARED.  The preferred state is whichever is compatible
  69 * with other granted locks, or the specified state if no other locks exist.
  70 *
  71 * LM_FLAG_PRIORITY
  72 * Override fairness considerations.  Suppose a lock is held in a shared state
  73 * and there is a pending request for the deferred state.  A shared lock
  74 * request with the priority flag would be allowed to bypass the deferred
  75 * request and directly join the other shared lock.  A shared lock request
  76 * without the priority flag might be forced to wait until the deferred
  77 * requested had acquired and released the lock.
  78 */
  79
  80#define LM_FLAG_TRY             0x0001
  81#define LM_FLAG_TRY_1CB         0x0002
  82#define LM_FLAG_NOEXP           0x0004
  83#define LM_FLAG_ANY             0x0008
  84#define LM_FLAG_PRIORITY        0x0010
  85#define GL_ASYNC                0x0040
  86#define GL_EXACT                0x0080
  87#define GL_SKIP                 0x0100
  88#define GL_NOCACHE              0x0400
  89  
  90/*
  91 * lm_async_cb return flags
  92 *
  93 * LM_OUT_ST_MASK
  94 * Masks the lower two bits of lock state in the returned value.
  95 *
  96 * LM_OUT_CANCELED
  97 * The lock request was canceled.
  98 *
  99 */
 100
 101#define LM_OUT_ST_MASK          0x00000003
 102#define LM_OUT_CANCELED         0x00000008
 103#define LM_OUT_ERROR            0x00000004
 104
 105/*
 106 * lm_recovery_done() messages
 107 */
 108
 109#define LM_RD_GAVEUP            308
 110#define LM_RD_SUCCESS           309
 111
 112#define GLR_TRYFAILED           13
 113
 114#define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
 115#define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
 116#define GL_GLOCK_MIN_HOLD        (long)(10)
 117#define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
 118#define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
 119
 120struct lm_lockops {
 121        const char *lm_proto_name;
 122        int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
 123        void (*lm_first_done) (struct gfs2_sbd *sdp);
 124        void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
 125                                    unsigned int result);
 126        void (*lm_unmount) (struct gfs2_sbd *sdp);
 127        void (*lm_withdraw) (struct gfs2_sbd *sdp);
 128        void (*lm_put_lock) (struct gfs2_glock *gl);
 129        int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
 130                        unsigned int flags);
 131        void (*lm_cancel) (struct gfs2_glock *gl);
 132        const match_table_t *lm_tokens;
 133};
 134
 135extern struct workqueue_struct *gfs2_delete_workqueue;
 136static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
 137{
 138        struct gfs2_holder *gh;
 139        struct pid *pid;
 140
 141        /* Look in glock's list of holders for one with current task as owner */
 142        spin_lock(&gl->gl_lockref.lock);
 143        pid = task_pid(current);
 144        list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 145                if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 146                        break;
 147                if (gh->gh_owner_pid == pid)
 148                        goto out;
 149        }
 150        gh = NULL;
 151out:
 152        spin_unlock(&gl->gl_lockref.lock);
 153
 154        return gh;
 155}
 156
 157static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
 158{
 159        return gl->gl_state == LM_ST_EXCLUSIVE;
 160}
 161
 162static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
 163{
 164        return gl->gl_state == LM_ST_DEFERRED;
 165}
 166
 167static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
 168{
 169        return gl->gl_state == LM_ST_SHARED;
 170}
 171
 172static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
 173{
 174        if (gl->gl_ops->go_flags & GLOF_ASPACE)
 175                return (struct address_space *)(gl + 1);
 176        return NULL;
 177}
 178
 179extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 180                          const struct gfs2_glock_operations *glops,
 181                          int create, struct gfs2_glock **glp);
 182extern void gfs2_glock_hold(struct gfs2_glock *gl);
 183extern void gfs2_glock_put(struct gfs2_glock *gl);
 184extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
 185extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
 186                             u16 flags, struct gfs2_holder *gh);
 187extern void gfs2_holder_reinit(unsigned int state, u16 flags,
 188                               struct gfs2_holder *gh);
 189extern void gfs2_holder_uninit(struct gfs2_holder *gh);
 190extern int gfs2_glock_nq(struct gfs2_holder *gh);
 191extern int gfs2_glock_poll(struct gfs2_holder *gh);
 192extern int gfs2_glock_wait(struct gfs2_holder *gh);
 193extern void gfs2_glock_dq(struct gfs2_holder *gh);
 194extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
 195extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 196extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
 197                             const struct gfs2_glock_operations *glops,
 198                             unsigned int state, u16 flags,
 199                             struct gfs2_holder *gh);
 200extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 201extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 202extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
 203                            bool fsid);
 204#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {              \
 205                        gfs2_dump_glock(NULL, gl, true);        \
 206                        BUG(); } } while(0)
 207extern __printf(2, 3)
 208void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
 209
 210/**
 211 * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
 212 * @gl: the glock
 213 * @state: the state we're requesting
 214 * @flags: the modifier flags
 215 * @gh: the holder structure
 216 *
 217 * Returns: 0, GLR_*, or errno
 218 */
 219
 220static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 221                                     unsigned int state, u16 flags,
 222                                     struct gfs2_holder *gh)
 223{
 224        int error;
 225
 226        gfs2_holder_init(gl, state, flags, gh);
 227
 228        error = gfs2_glock_nq(gh);
 229        if (error)
 230                gfs2_holder_uninit(gh);
 231
 232        return error;
 233}
 234
 235extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
 236extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
 237extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
 238extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
 239extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
 240extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
 241extern void gfs2_glock_free(struct gfs2_glock *gl);
 242
 243extern int __init gfs2_glock_init(void);
 244extern void gfs2_glock_exit(void);
 245
 246extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
 247extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
 248extern void gfs2_register_debugfs(void);
 249extern void gfs2_unregister_debugfs(void);
 250
 251extern const struct lm_lockops gfs2_dlm_ops;
 252
 253static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
 254{
 255        gh->gh_gl = NULL;
 256}
 257
 258static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
 259{
 260        return gh->gh_gl;
 261}
 262
 263/**
 264 * glock_set_object - set the gl_object field of a glock
 265 * @gl: the glock
 266 * @object: the object
 267 */
 268static inline void glock_set_object(struct gfs2_glock *gl, void *object)
 269{
 270        spin_lock(&gl->gl_lockref.lock);
 271        if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
 272                gfs2_dump_glock(NULL, gl, true);
 273        gl->gl_object = object;
 274        spin_unlock(&gl->gl_lockref.lock);
 275}
 276
 277/**
 278 * glock_clear_object - clear the gl_object field of a glock
 279 * @gl: the glock
 280 * @object: the object
 281 *
 282 * I'd love to similarly add this:
 283 *      else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
 284 *              gfs2_dump_glock(NULL, gl, true);
 285 * Unfortunately, that's not possible because as soon as gfs2_delete_inode
 286 * frees the block in the rgrp, another process can reassign it for an I_NEW
 287 * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
 288 * That means gfs2_delete_inode may subsequently try to call this function
 289 * for a glock that's already pointing to a brand new inode. If we clear the
 290 * new inode's gl_object, we'll introduce metadata corruption. Function
 291 * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
 292 * tries to clear gl_object, so it's more than just gfs2_delete_inode.
 293 *
 294 */
 295static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
 296{
 297        spin_lock(&gl->gl_lockref.lock);
 298        if (gl->gl_object == object)
 299                gl->gl_object = NULL;
 300        spin_unlock(&gl->gl_lockref.lock);
 301}
 302
 303#endif /* __GLOCK_DOT_H__ */
 304