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 * LM_FLAG_NODE_SCOPE
  80 * This holder agrees to share the lock within this node. In other words,
  81 * the glock is held in EX mode according to DLM, but local holders on the
  82 * same node can share it.
  83 */
  84
  85#define LM_FLAG_TRY             0x0001
  86#define LM_FLAG_TRY_1CB         0x0002
  87#define LM_FLAG_NOEXP           0x0004
  88#define LM_FLAG_ANY             0x0008
  89#define LM_FLAG_PRIORITY        0x0010
  90#define LM_FLAG_NODE_SCOPE      0x0020
  91#define GL_ASYNC                0x0040
  92#define GL_EXACT                0x0080
  93#define GL_SKIP                 0x0100
  94#define GL_NOCACHE              0x0400
  95  
  96/*
  97 * lm_async_cb return flags
  98 *
  99 * LM_OUT_ST_MASK
 100 * Masks the lower two bits of lock state in the returned value.
 101 *
 102 * LM_OUT_CANCELED
 103 * The lock request was canceled.
 104 *
 105 */
 106
 107#define LM_OUT_ST_MASK          0x00000003
 108#define LM_OUT_CANCELED         0x00000008
 109#define LM_OUT_ERROR            0x00000004
 110
 111/*
 112 * lm_recovery_done() messages
 113 */
 114
 115#define LM_RD_GAVEUP            308
 116#define LM_RD_SUCCESS           309
 117
 118#define GLR_TRYFAILED           13
 119
 120#define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
 121#define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
 122#define GL_GLOCK_MIN_HOLD        (long)(10)
 123#define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
 124#define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
 125
 126struct lm_lockops {
 127        const char *lm_proto_name;
 128        int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
 129        void (*lm_first_done) (struct gfs2_sbd *sdp);
 130        void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
 131                                    unsigned int result);
 132        void (*lm_unmount) (struct gfs2_sbd *sdp);
 133        void (*lm_withdraw) (struct gfs2_sbd *sdp);
 134        void (*lm_put_lock) (struct gfs2_glock *gl);
 135        int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
 136                        unsigned int flags);
 137        void (*lm_cancel) (struct gfs2_glock *gl);
 138        const match_table_t *lm_tokens;
 139};
 140
 141extern struct workqueue_struct *gfs2_delete_workqueue;
 142static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
 143{
 144        struct gfs2_holder *gh;
 145        struct pid *pid;
 146
 147        /* Look in glock's list of holders for one with current task as owner */
 148        spin_lock(&gl->gl_lockref.lock);
 149        pid = task_pid(current);
 150        list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 151                if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 152                        break;
 153                if (gh->gh_owner_pid == pid)
 154                        goto out;
 155        }
 156        gh = NULL;
 157out:
 158        spin_unlock(&gl->gl_lockref.lock);
 159
 160        return gh;
 161}
 162
 163static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
 164{
 165        return gl->gl_state == LM_ST_EXCLUSIVE;
 166}
 167
 168static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
 169{
 170        return gl->gl_state == LM_ST_DEFERRED;
 171}
 172
 173static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
 174{
 175        return gl->gl_state == LM_ST_SHARED;
 176}
 177
 178static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
 179{
 180        if (gl->gl_ops->go_flags & GLOF_ASPACE)
 181                return (struct address_space *)(gl + 1);
 182        return NULL;
 183}
 184
 185extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 186                          const struct gfs2_glock_operations *glops,
 187                          int create, struct gfs2_glock **glp);
 188extern void gfs2_glock_hold(struct gfs2_glock *gl);
 189extern void gfs2_glock_put(struct gfs2_glock *gl);
 190extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
 191extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
 192                             u16 flags, struct gfs2_holder *gh);
 193extern void gfs2_holder_reinit(unsigned int state, u16 flags,
 194                               struct gfs2_holder *gh);
 195extern void gfs2_holder_uninit(struct gfs2_holder *gh);
 196extern int gfs2_glock_nq(struct gfs2_holder *gh);
 197extern int gfs2_glock_poll(struct gfs2_holder *gh);
 198extern int gfs2_glock_wait(struct gfs2_holder *gh);
 199extern int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs);
 200extern void gfs2_glock_dq(struct gfs2_holder *gh);
 201extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
 202extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 203extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
 204                             const struct gfs2_glock_operations *glops,
 205                             unsigned int state, u16 flags,
 206                             struct gfs2_holder *gh);
 207extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 208extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 209extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
 210                            bool fsid);
 211#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {              \
 212                        gfs2_dump_glock(NULL, gl, true);        \
 213                        BUG(); } } while(0)
 214#define gfs2_glock_assert_warn(gl, x) do { if (unlikely(!(x))) {        \
 215                        gfs2_dump_glock(NULL, gl, true);                \
 216                        gfs2_assert_warn((gl)->gl_name.ln_sbd, (x)); } } \
 217        while (0)
 218#define gfs2_glock_assert_withdraw(gl, x) do { if (unlikely(!(x))) {    \
 219                        gfs2_dump_glock(NULL, gl, true);                \
 220                        gfs2_assert_withdraw((gl)->gl_name.ln_sbd, (x)); } } \
 221        while (0)
 222
 223extern __printf(2, 3)
 224void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
 225
 226/**
 227 * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
 228 * @gl: the glock
 229 * @state: the state we're requesting
 230 * @flags: the modifier flags
 231 * @gh: the holder structure
 232 *
 233 * Returns: 0, GLR_*, or errno
 234 */
 235
 236static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 237                                     unsigned int state, u16 flags,
 238                                     struct gfs2_holder *gh)
 239{
 240        int error;
 241
 242        gfs2_holder_init(gl, state, flags, gh);
 243
 244        error = gfs2_glock_nq(gh);
 245        if (error)
 246                gfs2_holder_uninit(gh);
 247
 248        return error;
 249}
 250
 251extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
 252extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
 253extern bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay);
 254extern void gfs2_cancel_delete_work(struct gfs2_glock *gl);
 255extern bool gfs2_delete_work_queued(const struct gfs2_glock *gl);
 256extern void gfs2_flush_delete_work(struct gfs2_sbd *sdp);
 257extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
 258extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
 259extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
 260extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
 261extern void gfs2_glock_free(struct gfs2_glock *gl);
 262
 263extern int __init gfs2_glock_init(void);
 264extern void gfs2_glock_exit(void);
 265
 266extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
 267extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
 268extern void gfs2_register_debugfs(void);
 269extern void gfs2_unregister_debugfs(void);
 270
 271extern const struct lm_lockops gfs2_dlm_ops;
 272
 273static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
 274{
 275        gh->gh_gl = NULL;
 276}
 277
 278static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
 279{
 280        return gh->gh_gl;
 281}
 282
 283static inline bool gfs2_holder_queued(struct gfs2_holder *gh)
 284{
 285        return !list_empty(&gh->gh_list);
 286}
 287
 288/**
 289 * glock_set_object - set the gl_object field of a glock
 290 * @gl: the glock
 291 * @object: the object
 292 */
 293static inline void glock_set_object(struct gfs2_glock *gl, void *object)
 294{
 295        spin_lock(&gl->gl_lockref.lock);
 296        if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
 297                gfs2_dump_glock(NULL, gl, true);
 298        gl->gl_object = object;
 299        spin_unlock(&gl->gl_lockref.lock);
 300}
 301
 302/**
 303 * glock_clear_object - clear the gl_object field of a glock
 304 * @gl: the glock
 305 * @object: the object
 306 *
 307 * I'd love to similarly add this:
 308 *      else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
 309 *              gfs2_dump_glock(NULL, gl, true);
 310 * Unfortunately, that's not possible because as soon as gfs2_delete_inode
 311 * frees the block in the rgrp, another process can reassign it for an I_NEW
 312 * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
 313 * That means gfs2_delete_inode may subsequently try to call this function
 314 * for a glock that's already pointing to a brand new inode. If we clear the
 315 * new inode's gl_object, we'll introduce metadata corruption. Function
 316 * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
 317 * tries to clear gl_object, so it's more than just gfs2_delete_inode.
 318 *
 319 */
 320static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
 321{
 322        spin_lock(&gl->gl_lockref.lock);
 323        if (gl->gl_object == object)
 324                gl->gl_object = NULL;
 325        spin_unlock(&gl->gl_lockref.lock);
 326}
 327
 328extern void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation);
 329extern bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation);
 330
 331#endif /* __GLOCK_DOT_H__ */
 332