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
  17 enum {
  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
 120 struct 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
 135 extern struct workqueue_struct *gfs2_delete_workqueue;
 136 static 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;
 151 out:
 152         spin_unlock(&gl->gl_lockref.lock);
 153
 154         return gh;
 155 }
 156
 157 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
 158 {
 159         return gl->gl_state == LM_ST_EXCLUSIVE;
 160 }
 161
 162 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
 163 {
 164         return gl->gl_state == LM_ST_DEFERRED;
 165 }
 166
 167 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
 168 {
 169         return gl->gl_state == LM_ST_SHARED;
 170 }
 171
 172 static 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
 179 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 180                           const struct gfs2_glock_operations *glops,
 181                           int create, struct gfs2_glock **glp);
 182 extern void gfs2_glock_hold(struct gfs2_glock *gl);
 183 extern void gfs2_glock_put(struct gfs2_glock *gl);
 184 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
 185 extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
 186                              u16 flags, struct gfs2_holder *gh);
 187 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
 188                                struct gfs2_holder *gh);
 189 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
 190 extern int gfs2_glock_nq(struct gfs2_holder *gh);
 191 extern int gfs2_glock_poll(struct gfs2_holder *gh);
 192 extern int gfs2_glock_wait(struct gfs2_holder *gh);
 193 extern int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs);
 194 extern void gfs2_glock_dq(struct gfs2_holder *gh);
 195 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
 196 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 197 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
 198                              const struct gfs2_glock_operations *glops,
 199                              unsigned int state, u16 flags,
 200                              struct gfs2_holder *gh);
 201 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 202 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 203 extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
 204                             bool fsid);
 205 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {              \
 206                         gfs2_dump_glock(NULL, gl, true);        \
 207                         BUG(); } } while(0)
 208 extern __printf(2, 3)
 209 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
 210
 211 /**
 212  * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
 213  * @gl: the glock
 214  * @state: the state we're requesting
 215  * @flags: the modifier flags
 216  * @gh: the holder structure
 217  *
 218  * Returns: 0, GLR_*, or errno
 219  */
 220
 221 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 222                                      unsigned int state, u16 flags,
 223                                      struct gfs2_holder *gh)
 224 {
 225         int error;
 226
 227         gfs2_holder_init(gl, state, flags, gh);
 228
 229         error = gfs2_glock_nq(gh);
 230         if (error)
 231                 gfs2_holder_uninit(gh);
 232
 233         return error;
 234 }
 235
 236 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
 237 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
 238 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
 239 extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
 240 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
 241 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
 242 extern void gfs2_glock_free(struct gfs2_glock *gl);
 243
 244 extern int __init gfs2_glock_init(void);
 245 extern void gfs2_glock_exit(void);
 246
 247 extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
 248 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
 249 extern void gfs2_register_debugfs(void);
 250 extern void gfs2_unregister_debugfs(void);
 251
 252 extern const struct lm_lockops gfs2_dlm_ops;
 253
 254 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
 255 {
 256         gh->gh_gl = NULL;
 257 }
 258
 259 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
 260 {
 261         return gh->gh_gl;
 262 }
 263
 264 static inline bool gfs2_holder_queued(struct gfs2_holder *gh)
 265 {
 266         return !list_empty(&gh->gh_list);
 267 }
 268
 269 /**
 270  * glock_set_object - set the gl_object field of a glock
 271  * @gl: the glock
 272  * @object: the object
 273  */
 274 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
 275 {
 276         spin_lock(&gl->gl_lockref.lock);
 277         if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
 278                 gfs2_dump_glock(NULL, gl, true);
 279         gl->gl_object = object;
 280         spin_unlock(&gl->gl_lockref.lock);
 281 }
 282
 283 /**
 284  * glock_clear_object - clear the gl_object field of a glock
 285  * @gl: the glock
 286  * @object: the object
 287  *
 288  * I'd love to similarly add this:
 289  *      else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
 290  *              gfs2_dump_glock(NULL, gl, true);
 291  * Unfortunately, that's not possible because as soon as gfs2_delete_inode
 292  * frees the block in the rgrp, another process can reassign it for an I_NEW
 293  * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
 294  * That means gfs2_delete_inode may subsequently try to call this function
 295  * for a glock that's already pointing to a brand new inode. If we clear the
 296  * new inode's gl_object, we'll introduce metadata corruption. Function
 297  * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
 298  * tries to clear gl_object, so it's more than just gfs2_delete_inode.
 299  *
 300  */
 301 static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
 302 {
 303         spin_lock(&gl->gl_lockref.lock);
 304         if (gl->gl_object == object)
 305                 gl->gl_object = NULL;
 306         spin_unlock(&gl->gl_lockref.lock);
 307 }
 308
 309 #endif /* __GLOCK_DOT_H__ */