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0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
0004  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
0005  */
0006 
0007 #ifndef __GLOCK_DOT_H__
0008 #define __GLOCK_DOT_H__
0009 
0010 #include <linux/sched.h>
0011 #include <linux/parser.h>
0012 #include "incore.h"
0013 #include "util.h"
0014 
0015 /* Options for hostdata parser */
0016 
0017 enum {
0018     Opt_jid,
0019     Opt_id,
0020     Opt_first,
0021     Opt_nodir,
0022     Opt_err,
0023 };
0024 
0025 /*
0026  * lm_lockname types
0027  */
0028 
0029 #define LM_TYPE_RESERVED    0x00
0030 #define LM_TYPE_NONDISK     0x01
0031 #define LM_TYPE_INODE       0x02
0032 #define LM_TYPE_RGRP        0x03
0033 #define LM_TYPE_META        0x04
0034 #define LM_TYPE_IOPEN       0x05
0035 #define LM_TYPE_FLOCK       0x06
0036 #define LM_TYPE_PLOCK       0x07
0037 #define LM_TYPE_QUOTA       0x08
0038 #define LM_TYPE_JOURNAL     0x09
0039 
0040 /*
0041  * lm_lock() states
0042  *
0043  * SHARED is compatible with SHARED, not with DEFERRED or EX.
0044  * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
0045  */
0046 
0047 #define LM_ST_UNLOCKED      0
0048 #define LM_ST_EXCLUSIVE     1
0049 #define LM_ST_DEFERRED      2
0050 #define LM_ST_SHARED        3
0051 
0052 /*
0053  * lm_lock() flags
0054  *
0055  * LM_FLAG_TRY
0056  * Don't wait to acquire the lock if it can't be granted immediately.
0057  *
0058  * LM_FLAG_TRY_1CB
0059  * Send one blocking callback if TRY is set and the lock is not granted.
0060  *
0061  * LM_FLAG_NOEXP
0062  * GFS sets this flag on lock requests it makes while doing journal recovery.
0063  * These special requests should not be blocked due to the recovery like
0064  * ordinary locks would be.
0065  *
0066  * LM_FLAG_ANY
0067  * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
0068  * also be granted in SHARED.  The preferred state is whichever is compatible
0069  * with other granted locks, or the specified state if no other locks exist.
0070  *
0071  * LM_FLAG_PRIORITY
0072  * Override fairness considerations.  Suppose a lock is held in a shared state
0073  * and there is a pending request for the deferred state.  A shared lock
0074  * request with the priority flag would be allowed to bypass the deferred
0075  * request and directly join the other shared lock.  A shared lock request
0076  * without the priority flag might be forced to wait until the deferred
0077  * requested had acquired and released the lock.
0078  *
0079  * LM_FLAG_NODE_SCOPE
0080  * This holder agrees to share the lock within this node. In other words,
0081  * the glock is held in EX mode according to DLM, but local holders on the
0082  * same node can share it.
0083  */
0084 
0085 #define LM_FLAG_TRY     0x0001
0086 #define LM_FLAG_TRY_1CB     0x0002
0087 #define LM_FLAG_NOEXP       0x0004
0088 #define LM_FLAG_ANY     0x0008
0089 #define LM_FLAG_PRIORITY    0x0010
0090 #define LM_FLAG_NODE_SCOPE  0x0020
0091 #define GL_ASYNC        0x0040
0092 #define GL_EXACT        0x0080
0093 #define GL_SKIP         0x0100
0094 #define GL_NOCACHE      0x0400
0095   
0096 /*
0097  * lm_async_cb return flags
0098  *
0099  * LM_OUT_ST_MASK
0100  * Masks the lower two bits of lock state in the returned value.
0101  *
0102  * LM_OUT_CANCELED
0103  * The lock request was canceled.
0104  *
0105  */
0106 
0107 #define LM_OUT_ST_MASK      0x00000003
0108 #define LM_OUT_CANCELED     0x00000008
0109 #define LM_OUT_ERROR        0x00000004
0110 
0111 /*
0112  * lm_recovery_done() messages
0113  */
0114 
0115 #define LM_RD_GAVEUP        308
0116 #define LM_RD_SUCCESS       309
0117 
0118 #define GLR_TRYFAILED       13
0119 
0120 #define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
0121 #define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
0122 #define GL_GLOCK_MIN_HOLD        (long)(10)
0123 #define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
0124 #define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
0125 
0126 struct lm_lockops {
0127     const char *lm_proto_name;
0128     int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
0129     void (*lm_first_done) (struct gfs2_sbd *sdp);
0130     void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
0131                     unsigned int result);
0132     void (*lm_unmount) (struct gfs2_sbd *sdp);
0133     void (*lm_withdraw) (struct gfs2_sbd *sdp);
0134     void (*lm_put_lock) (struct gfs2_glock *gl);
0135     int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
0136             unsigned int flags);
0137     void (*lm_cancel) (struct gfs2_glock *gl);
0138     const match_table_t *lm_tokens;
0139 };
0140 
0141 struct gfs2_glock_aspace {
0142     struct gfs2_glock glock;
0143     struct address_space mapping;
0144 };
0145 
0146 extern struct workqueue_struct *gfs2_delete_workqueue;
0147 static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
0148 {
0149     struct gfs2_holder *gh;
0150     struct pid *pid;
0151 
0152     /* Look in glock's list of holders for one with current task as owner */
0153     spin_lock(&gl->gl_lockref.lock);
0154     pid = task_pid(current);
0155     list_for_each_entry(gh, &gl->gl_holders, gh_list) {
0156         if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
0157             break;
0158         if (test_bit(HIF_MAY_DEMOTE, &gh->gh_iflags))
0159             continue;
0160         if (gh->gh_owner_pid == pid)
0161             goto out;
0162     }
0163     gh = NULL;
0164 out:
0165     spin_unlock(&gl->gl_lockref.lock);
0166 
0167     return gh;
0168 }
0169 
0170 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
0171 {
0172     return gl->gl_state == LM_ST_EXCLUSIVE;
0173 }
0174 
0175 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
0176 {
0177     return gl->gl_state == LM_ST_DEFERRED;
0178 }
0179 
0180 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
0181 {
0182     return gl->gl_state == LM_ST_SHARED;
0183 }
0184 
0185 static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
0186 {
0187     if (gl->gl_ops->go_flags & GLOF_ASPACE) {
0188         struct gfs2_glock_aspace *gla =
0189             container_of(gl, struct gfs2_glock_aspace, glock);
0190         return &gla->mapping;
0191     }
0192     return NULL;
0193 }
0194 
0195 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
0196               const struct gfs2_glock_operations *glops,
0197               int create, struct gfs2_glock **glp);
0198 extern void gfs2_glock_hold(struct gfs2_glock *gl);
0199 extern void gfs2_glock_put(struct gfs2_glock *gl);
0200 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
0201 
0202 extern void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
0203                    u16 flags, struct gfs2_holder *gh,
0204                    unsigned long ip);
0205 static inline void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
0206                     u16 flags, struct gfs2_holder *gh) {
0207     __gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
0208 }
0209 
0210 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
0211                    struct gfs2_holder *gh);
0212 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
0213 extern int gfs2_glock_nq(struct gfs2_holder *gh);
0214 extern int gfs2_glock_poll(struct gfs2_holder *gh);
0215 extern int gfs2_instantiate(struct gfs2_holder *gh);
0216 extern int gfs2_glock_holder_ready(struct gfs2_holder *gh);
0217 extern int gfs2_glock_wait(struct gfs2_holder *gh);
0218 extern int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs);
0219 extern void gfs2_glock_dq(struct gfs2_holder *gh);
0220 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
0221 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
0222 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
0223                  const struct gfs2_glock_operations *glops,
0224                  unsigned int state, u16 flags,
0225                  struct gfs2_holder *gh);
0226 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
0227 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
0228 extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
0229                 bool fsid);
0230 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {      \
0231             gfs2_dump_glock(NULL, gl, true);    \
0232             BUG(); } } while(0)
0233 #define gfs2_glock_assert_warn(gl, x) do { if (unlikely(!(x))) {    \
0234             gfs2_dump_glock(NULL, gl, true);        \
0235             gfs2_assert_warn((gl)->gl_name.ln_sbd, (x)); } } \
0236     while (0)
0237 #define gfs2_glock_assert_withdraw(gl, x) do { if (unlikely(!(x))) {    \
0238             gfs2_dump_glock(NULL, gl, true);        \
0239             gfs2_assert_withdraw((gl)->gl_name.ln_sbd, (x)); } } \
0240     while (0)
0241 
0242 extern __printf(2, 3)
0243 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
0244 
0245 /**
0246  * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
0247  * @gl: the glock
0248  * @state: the state we're requesting
0249  * @flags: the modifier flags
0250  * @gh: the holder structure
0251  *
0252  * Returns: 0, GLR_*, or errno
0253  */
0254 
0255 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
0256                      unsigned int state, u16 flags,
0257                      struct gfs2_holder *gh)
0258 {
0259     int error;
0260 
0261     __gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
0262 
0263     error = gfs2_glock_nq(gh);
0264     if (error)
0265         gfs2_holder_uninit(gh);
0266 
0267     return error;
0268 }
0269 
0270 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
0271 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
0272 extern bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay);
0273 extern void gfs2_cancel_delete_work(struct gfs2_glock *gl);
0274 extern bool gfs2_delete_work_queued(const struct gfs2_glock *gl);
0275 extern void gfs2_flush_delete_work(struct gfs2_sbd *sdp);
0276 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
0277 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
0278 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
0279 extern void gfs2_glock_free(struct gfs2_glock *gl);
0280 
0281 extern int __init gfs2_glock_init(void);
0282 extern void gfs2_glock_exit(void);
0283 
0284 extern void gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
0285 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
0286 extern void gfs2_register_debugfs(void);
0287 extern void gfs2_unregister_debugfs(void);
0288 
0289 extern const struct lm_lockops gfs2_dlm_ops;
0290 
0291 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
0292 {
0293     gh->gh_gl = NULL;
0294 }
0295 
0296 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
0297 {
0298     return gh->gh_gl;
0299 }
0300 
0301 static inline bool gfs2_holder_queued(struct gfs2_holder *gh)
0302 {
0303     return !list_empty(&gh->gh_list);
0304 }
0305 
0306 /**
0307  * glock_set_object - set the gl_object field of a glock
0308  * @gl: the glock
0309  * @object: the object
0310  */
0311 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
0312 {
0313     spin_lock(&gl->gl_lockref.lock);
0314     if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
0315         gfs2_dump_glock(NULL, gl, true);
0316     gl->gl_object = object;
0317     spin_unlock(&gl->gl_lockref.lock);
0318 }
0319 
0320 /**
0321  * glock_clear_object - clear the gl_object field of a glock
0322  * @gl: the glock
0323  * @object: the object
0324  *
0325  * I'd love to similarly add this:
0326  *  else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
0327  *      gfs2_dump_glock(NULL, gl, true);
0328  * Unfortunately, that's not possible because as soon as gfs2_delete_inode
0329  * frees the block in the rgrp, another process can reassign it for an I_NEW
0330  * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
0331  * That means gfs2_delete_inode may subsequently try to call this function
0332  * for a glock that's already pointing to a brand new inode. If we clear the
0333  * new inode's gl_object, we'll introduce metadata corruption. Function
0334  * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
0335  * tries to clear gl_object, so it's more than just gfs2_delete_inode.
0336  *
0337  */
0338 static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
0339 {
0340     spin_lock(&gl->gl_lockref.lock);
0341     if (gl->gl_object == object)
0342         gl->gl_object = NULL;
0343     spin_unlock(&gl->gl_lockref.lock);
0344 }
0345 
0346 static inline void gfs2_holder_allow_demote(struct gfs2_holder *gh)
0347 {
0348     struct gfs2_glock *gl = gh->gh_gl;
0349 
0350     spin_lock(&gl->gl_lockref.lock);
0351     set_bit(HIF_MAY_DEMOTE, &gh->gh_iflags);
0352     spin_unlock(&gl->gl_lockref.lock);
0353 }
0354 
0355 static inline void gfs2_holder_disallow_demote(struct gfs2_holder *gh)
0356 {
0357     struct gfs2_glock *gl = gh->gh_gl;
0358 
0359     spin_lock(&gl->gl_lockref.lock);
0360     clear_bit(HIF_MAY_DEMOTE, &gh->gh_iflags);
0361     spin_unlock(&gl->gl_lockref.lock);
0362 }
0363 
0364 extern void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation);
0365 extern bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation);
0366 
0367 #endif /* __GLOCK_DOT_H__ */
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