/* * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions * of the GNU General Public License version 2. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "gfs2.h" #include "incore.h" #include "glock.h" #include "glops.h" #include "inode.h" #include "lops.h" #include "meta_io.h" #include "quota.h" #include "super.h" #include "util.h" #include "bmap.h" #define CREATE_TRACE_POINTS #include "trace_gfs2.h" struct gfs2_gl_hash_bucket { struct hlist_head hb_list; }; struct gfs2_glock_iter { int hash; /* hash bucket index */ struct gfs2_sbd *sdp; /* incore superblock */ struct gfs2_glock *gl; /* current glock struct */ char string[512]; /* scratch space */ }; typedef void (*glock_examiner) (struct gfs2_glock * gl); static int gfs2_dump_lockstate(struct gfs2_sbd *sdp); static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl); #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { __dump_glock(NULL, gl); BUG(); } } while(0) static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target); static DECLARE_RWSEM(gfs2_umount_flush_sem); static struct dentry *gfs2_root; static struct workqueue_struct *glock_workqueue; struct workqueue_struct *gfs2_delete_workqueue; static LIST_HEAD(lru_list); static atomic_t lru_count = ATOMIC_INIT(0); static DEFINE_SPINLOCK(lru_lock); #define GFS2_GL_HASH_SHIFT 15 #define GFS2_GL_HASH_SIZE (1 << GFS2_GL_HASH_SHIFT) #define GFS2_GL_HASH_MASK (GFS2_GL_HASH_SIZE - 1) static struct gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE]; static struct dentry *gfs2_root; /* * Despite what you might think, the numbers below are not arbitrary :-) * They are taken from the ipv4 routing hash code, which is well tested * and thus should be nearly optimal. Later on we might tweek the numbers * but for now this should be fine. * * The reason for putting the locks in a separate array from the list heads * is that we can have fewer locks than list heads and save memory. We use * the same hash function for both, but with a different hash mask. */ #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \ defined(CONFIG_PROVE_LOCKING) #ifdef CONFIG_LOCKDEP # define GL_HASH_LOCK_SZ 256 #else # if NR_CPUS >= 32 # define GL_HASH_LOCK_SZ 4096 # elif NR_CPUS >= 16 # define GL_HASH_LOCK_SZ 2048 # elif NR_CPUS >= 8 # define GL_HASH_LOCK_SZ 1024 # elif NR_CPUS >= 4 # define GL_HASH_LOCK_SZ 512 # else # define GL_HASH_LOCK_SZ 256 # endif #endif /* We never want more locks than chains */ #if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ # undef GL_HASH_LOCK_SZ # define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE #endif static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ]; static inline rwlock_t *gl_lock_addr(unsigned int x) { return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)]; } #else /* not SMP, so no spinlocks required */ static inline rwlock_t *gl_lock_addr(unsigned int x) { return NULL; } #endif /** * gl_hash() - Turn glock number into hash bucket number * @lock: The glock number * * Returns: The number of the corresponding hash bucket */ static unsigned int gl_hash(const struct gfs2_sbd *sdp, const struct lm_lockname *name) { unsigned int h; h = jhash(&name->ln_number, sizeof(u64), 0); h = jhash(&name->ln_type, sizeof(unsigned int), h); h = jhash(&sdp, sizeof(struct gfs2_sbd *), h); h &= GFS2_GL_HASH_MASK; return h; } /** * glock_free() - Perform a few checks and then release struct gfs2_glock * @gl: The glock to release * * Also calls lock module to release its internal structure for this glock. * */ static void glock_free(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_sbd; struct address_space *mapping = gfs2_glock2aspace(gl); struct kmem_cache *cachep = gfs2_glock_cachep; GLOCK_BUG_ON(gl, mapping && mapping->nrpages); trace_gfs2_glock_put(gl); if (mapping) cachep = gfs2_glock_aspace_cachep; sdp->sd_lockstruct.ls_ops->lm_put_lock(cachep, gl); } /** * gfs2_glock_hold() - increment reference count on glock * @gl: The glock to hold * */ void gfs2_glock_hold(struct gfs2_glock *gl) { GLOCK_BUG_ON(gl, atomic_read(&gl->gl_ref) == 0); atomic_inc(&gl->gl_ref); } /** * demote_ok - Check to see if it's ok to unlock a glock * @gl: the glock * * Returns: 1 if it's ok */ static int demote_ok(const struct gfs2_glock *gl) { const struct gfs2_glock_operations *glops = gl->gl_ops; if (gl->gl_state == LM_ST_UNLOCKED) return 0; if (!list_empty(&gl->gl_holders)) return 0; if (glops->go_demote_ok) return glops->go_demote_ok(gl); return 1; } /** * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list * @gl: the glock * */ static void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl) { int may_reclaim; may_reclaim = (demote_ok(gl) && (atomic_read(&gl->gl_ref) == 1 || (gl->gl_name.ln_type == LM_TYPE_INODE && atomic_read(&gl->gl_ref) <= 2))); spin_lock(&lru_lock); if (list_empty(&gl->gl_lru) && may_reclaim) { list_add_tail(&gl->gl_lru, &lru_list); atomic_inc(&lru_count); } spin_unlock(&lru_lock); } /** * gfs2_glock_put_nolock() - Decrement reference count on glock * @gl: The glock to put * * This function should only be used if the caller has its own reference * to the glock, in addition to the one it is dropping. */ void gfs2_glock_put_nolock(struct gfs2_glock *gl) { if (atomic_dec_and_test(&gl->gl_ref)) GLOCK_BUG_ON(gl, 1); gfs2_glock_schedule_for_reclaim(gl); } /** * gfs2_glock_put() - Decrement reference count on glock * @gl: The glock to put * */ int gfs2_glock_put(struct gfs2_glock *gl) { int rv = 0; write_lock(gl_lock_addr(gl->gl_hash)); if (atomic_dec_and_lock(&gl->gl_ref, &lru_lock)) { hlist_del(&gl->gl_list); if (!list_empty(&gl->gl_lru)) { list_del_init(&gl->gl_lru); atomic_dec(&lru_count); } spin_unlock(&lru_lock); write_unlock(gl_lock_addr(gl->gl_hash)); GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders)); glock_free(gl); rv = 1; goto out; } spin_lock(&gl->gl_spin); gfs2_glock_schedule_for_reclaim(gl); spin_unlock(&gl->gl_spin); write_unlock(gl_lock_addr(gl->gl_hash)); out: return rv; } /** * search_bucket() - Find struct gfs2_glock by lock number * @bucket: the bucket to search * @name: The lock name * * Returns: NULL, or the struct gfs2_glock with the requested number */ static struct gfs2_glock *search_bucket(unsigned int hash, const struct gfs2_sbd *sdp, const struct lm_lockname *name) { struct gfs2_glock *gl; struct hlist_node *h; hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, gl_list) { if (!lm_name_equal(&gl->gl_name, name)) continue; if (gl->gl_sbd != sdp) continue; atomic_inc(&gl->gl_ref); return gl; } return NULL; } /** * may_grant - check if its ok to grant a new lock * @gl: The glock * @gh: The lock request which we wish to grant * * Returns: true if its ok to grant the lock */ static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh) { const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list); if ((gh->gh_state == LM_ST_EXCLUSIVE || gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head) return 0; if (gl->gl_state == gh->gh_state) return 1; if (gh->gh_flags & GL_EXACT) return 0; if (gl->gl_state == LM_ST_EXCLUSIVE) { if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED) return 1; if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED) return 1; } if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY)) return 1; return 0; } static void gfs2_holder_wake(struct gfs2_holder *gh) { clear_bit(HIF_WAIT, &gh->gh_iflags); smp_mb__after_clear_bit(); wake_up_bit(&gh->gh_iflags, HIF_WAIT); } /** * do_promote - promote as many requests as possible on the current queue * @gl: The glock * * Returns: 1 if there is a blocked holder at the head of the list, or 2 * if a type specific operation is underway. */ static int do_promote(struct gfs2_glock *gl) __releases(&gl->gl_spin) __acquires(&gl->gl_spin) { const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_holder *gh, *tmp; int ret; restart: list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { if (test_bit(HIF_HOLDER, &gh->gh_iflags)) continue; if (may_grant(gl, gh)) { if (gh->gh_list.prev == &gl->gl_holders && glops->go_lock) { spin_unlock(&gl->gl_spin); /* FIXME: eliminate this eventually */ ret = glops->go_lock(gh); spin_lock(&gl->gl_spin); if (ret) { if (ret == 1) return 2; gh->gh_error = ret; list_del_init(&gh->gh_list); trace_gfs2_glock_queue(gh, 0); gfs2_holder_wake(gh); goto restart; } set_bit(HIF_HOLDER, &gh->gh_iflags); trace_gfs2_promote(gh, 1); gfs2_holder_wake(gh); goto restart; } set_bit(HIF_HOLDER, &gh->gh_iflags); trace_gfs2_promote(gh, 0); gfs2_holder_wake(gh); continue; } if (gh->gh_list.prev == &gl->gl_holders) return 1; break; } return 0; } /** * do_error - Something unexpected has happened during a lock request * */ static inline void do_error(struct gfs2_glock *gl, const int ret) { struct gfs2_holder *gh, *tmp; list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { if (test_bit(HIF_HOLDER, &gh->gh_iflags)) continue; if (ret & LM_OUT_ERROR) gh->gh_error = -EIO; else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) gh->gh_error = GLR_TRYFAILED; else continue; list_del_init(&gh->gh_list); trace_gfs2_glock_queue(gh, 0); gfs2_holder_wake(gh); } } /** * find_first_waiter - find the first gh that's waiting for the glock * @gl: the glock */ static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl) { struct gfs2_holder *gh; list_for_each_entry(gh, &gl->gl_holders, gh_list) { if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) return gh; } return NULL; } /** * state_change - record that the glock is now in a different state * @gl: the glock * @new_state the new state * */ static void state_change(struct gfs2_glock *gl, unsigned int new_state) { int held1, held2; held1 = (gl->gl_state != LM_ST_UNLOCKED); held2 = (new_state != LM_ST_UNLOCKED); if (held1 != held2) { if (held2) gfs2_glock_hold(gl); else gfs2_glock_put_nolock(gl); } gl->gl_state = new_state; gl->gl_tchange = jiffies; } static void gfs2_demote_wake(struct gfs2_glock *gl) { gl->gl_demote_state = LM_ST_EXCLUSIVE; clear_bit(GLF_DEMOTE, &gl->gl_flags); smp_mb__after_clear_bit(); wake_up_bit(&gl->gl_flags, GLF_DEMOTE); } /** * finish_xmote - The DLM has replied to one of our lock requests * @gl: The glock * @ret: The status from the DLM * */ static void finish_xmote(struct gfs2_glock *gl, unsigned int ret) { const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_holder *gh; unsigned state = ret & LM_OUT_ST_MASK; int rv; spin_lock(&gl->gl_spin); trace_gfs2_glock_state_change(gl, state); state_change(gl, state); gh = find_first_waiter(gl); /* Demote to UN request arrived during demote to SH or DF */ if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) && state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED) gl->gl_target = LM_ST_UNLOCKED; /* Check for state != intended state */ if (unlikely(state != gl->gl_target)) { if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) { /* move to back of queue and try next entry */ if (ret & LM_OUT_CANCELED) { if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0) list_move_tail(&gh->gh_list, &gl->gl_holders); gh = find_first_waiter(gl); gl->gl_target = gh->gh_state; goto retry; } /* Some error or failed "try lock" - report it */ if ((ret & LM_OUT_ERROR) || (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) { gl->gl_target = gl->gl_state; do_error(gl, ret); goto out; } } switch(state) { /* Unlocked due to conversion deadlock, try again */ case LM_ST_UNLOCKED: retry: do_xmote(gl, gh, gl->gl_target); break; /* Conversion fails, unlock and try again */ case LM_ST_SHARED: case LM_ST_DEFERRED: do_xmote(gl, gh, LM_ST_UNLOCKED); break; default: /* Everything else */ printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state); GLOCK_BUG_ON(gl, 1); } spin_unlock(&gl->gl_spin); return; } /* Fast path - we got what we asked for */ if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) gfs2_demote_wake(gl); if (state != LM_ST_UNLOCKED) { if (glops->go_xmote_bh) { spin_unlock(&gl->gl_spin); rv = glops->go_xmote_bh(gl, gh); spin_lock(&gl->gl_spin); if (rv) { do_error(gl, rv); goto out; } } rv = do_promote(gl); if (rv == 2) goto out_locked; } out: clear_bit(GLF_LOCK, &gl->gl_flags); out_locked: spin_unlock(&gl->gl_spin); } static unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, void *lock, unsigned int req_state, unsigned int flags) { int ret = LM_OUT_ERROR; if (!sdp->sd_lockstruct.ls_ops->lm_lock) return req_state == LM_ST_UNLOCKED ? 0 : req_state; if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) ret = sdp->sd_lockstruct.ls_ops->lm_lock(lock, req_state, flags); return ret; } /** * do_xmote - Calls the DLM to change the state of a lock * @gl: The lock state * @gh: The holder (only for promotes) * @target: The target lock state * */ static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target) __releases(&gl->gl_spin) __acquires(&gl->gl_spin) { const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_sbd *sdp = gl->gl_sbd; unsigned int lck_flags = gh ? gh->gh_flags : 0; int ret; lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP | LM_FLAG_PRIORITY); BUG_ON(gl->gl_state == target); BUG_ON(gl->gl_state == gl->gl_target); if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) && glops->go_inval) { set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags); do_error(gl, 0); /* Fail queued try locks */ } spin_unlock(&gl->gl_spin); if (glops->go_xmote_th) glops->go_xmote_th(gl); if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA); clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags); gfs2_glock_hold(gl); if (target != LM_ST_UNLOCKED && (gl->gl_state == LM_ST_SHARED || gl->gl_state == LM_ST_DEFERRED) && !(lck_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) lck_flags |= LM_FLAG_TRY_1CB; ret = gfs2_lm_lock(sdp, gl, target, lck_flags); if (!(ret & LM_OUT_ASYNC)) { finish_xmote(gl, ret); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put(gl); } else { GLOCK_BUG_ON(gl, ret != LM_OUT_ASYNC); } spin_lock(&gl->gl_spin); } /** * find_first_holder - find the first "holder" gh * @gl: the glock */ static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl) { struct gfs2_holder *gh; if (!list_empty(&gl->gl_holders)) { gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list); if (test_bit(HIF_HOLDER, &gh->gh_iflags)) return gh; } return NULL; } /** * run_queue - do all outstanding tasks related to a glock * @gl: The glock in question * @nonblock: True if we must not block in run_queue * */ static void run_queue(struct gfs2_glock *gl, const int nonblock) __releases(&gl->gl_spin) __acquires(&gl->gl_spin) { struct gfs2_holder *gh = NULL; int ret; if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) return; GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)); if (test_bit(GLF_DEMOTE, &gl->gl_flags) && gl->gl_demote_state != gl->gl_state) { if (find_first_holder(gl)) goto out_unlock; if (nonblock) goto out_sched; set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags); GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE); gl->gl_target = gl->gl_demote_state; } else { if (test_bit(GLF_DEMOTE, &gl->gl_flags)) gfs2_demote_wake(gl); ret = do_promote(gl); if (ret == 0) goto out_unlock; if (ret == 2) goto out; gh = find_first_waiter(gl); gl->gl_target = gh->gh_state; if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) do_error(gl, 0); /* Fail queued try locks */ } do_xmote(gl, gh, gl->gl_target); out: return; out_sched: clear_bit(GLF_LOCK, &gl->gl_flags); smp_mb__after_clear_bit(); gfs2_glock_hold(gl); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put_nolock(gl); return; out_unlock: clear_bit(GLF_LOCK, &gl->gl_flags); smp_mb__after_clear_bit(); return; } static void delete_work_func(struct work_struct *work) { struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete); struct gfs2_sbd *sdp = gl->gl_sbd; struct gfs2_inode *ip = NULL; struct inode *inode; u64 no_addr = 0; spin_lock(&gl->gl_spin); ip = (struct gfs2_inode *)gl->gl_object; if (ip) no_addr = ip->i_no_addr; spin_unlock(&gl->gl_spin); if (ip) { inode = gfs2_ilookup(sdp->sd_vfs, no_addr); if (inode) { d_prune_aliases(inode); iput(inode); } } gfs2_glock_put(gl); } static void glock_work_func(struct work_struct *work) { unsigned long delay = 0; struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work); int drop_ref = 0; if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) { finish_xmote(gl, gl->gl_reply); drop_ref = 1; } down_read(&gfs2_umount_flush_sem); spin_lock(&gl->gl_spin); if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && gl->gl_state != LM_ST_UNLOCKED && gl->gl_demote_state != LM_ST_EXCLUSIVE) { unsigned long holdtime, now = jiffies; holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time; if (time_before(now, holdtime)) delay = holdtime - now; set_bit(delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE, &gl->gl_flags); } run_queue(gl, 0); spin_unlock(&gl->gl_spin); up_read(&gfs2_umount_flush_sem); if (!delay || queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0) gfs2_glock_put(gl); if (drop_ref) gfs2_glock_put(gl); } /** * gfs2_glock_get() - Get a glock, or create one if one doesn't exist * @sdp: The GFS2 superblock * @number: the lock number * @glops: The glock_operations to use * @create: If 0, don't create the glock if it doesn't exist * @glp: the glock is returned here * * This does not lock a glock, just finds/creates structures for one. * * Returns: errno */ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, const struct gfs2_glock_operations *glops, int create, struct gfs2_glock **glp) { struct super_block *s = sdp->sd_vfs; struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type }; struct gfs2_glock *gl, *tmp; unsigned int hash = gl_hash(sdp, &name); struct address_space *mapping; read_lock(gl_lock_addr(hash)); gl = search_bucket(hash, sdp, &name); read_unlock(gl_lock_addr(hash)); *glp = gl; if (gl) return 0; if (!create) return -ENOENT; if (glops->go_flags & GLOF_ASPACE) gl = kmem_cache_alloc(gfs2_glock_aspace_cachep, GFP_KERNEL); else gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL); if (!gl) return -ENOMEM; atomic_inc(&sdp->sd_glock_disposal); gl->gl_flags = 0; gl->gl_name = name; atomic_set(&gl->gl_ref, 1); gl->gl_state = LM_ST_UNLOCKED; gl->gl_target = LM_ST_UNLOCKED; gl->gl_demote_state = LM_ST_EXCLUSIVE; gl->gl_hash = hash; gl->gl_ops = glops; snprintf(gl->gl_strname, GDLM_STRNAME_BYTES, "%8x%16llx", name.ln_type, (unsigned long long)number); memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb)); gl->gl_lksb.sb_lvbptr = gl->gl_lvb; gl->gl_tchange = jiffies; gl->gl_object = NULL; gl->gl_sbd = sdp; INIT_DELAYED_WORK(&gl->gl_work, glock_work_func); INIT_WORK(&gl->gl_delete, delete_work_func); mapping = gfs2_glock2aspace(gl); if (mapping) { mapping->a_ops = &gfs2_meta_aops; mapping->host = s->s_bdev->bd_inode; mapping->flags = 0; mapping_set_gfp_mask(mapping, GFP_NOFS); mapping->assoc_mapping = NULL; mapping->backing_dev_info = s->s_bdi; mapping->writeback_index = 0; } write_lock(gl_lock_addr(hash)); tmp = search_bucket(hash, sdp, &name); if (tmp) { write_unlock(gl_lock_addr(hash)); glock_free(gl); gl = tmp; } else { hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list); write_unlock(gl_lock_addr(hash)); } *glp = gl; return 0; } /** * gfs2_holder_init - initialize a struct gfs2_holder in the default way * @gl: the glock * @state: the state we're requesting * @flags: the modifier flags * @gh: the holder structure * */ void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags, struct gfs2_holder *gh) { INIT_LIST_HEAD(&gh->gh_list); gh->gh_gl = gl; gh->gh_ip = (unsigned long)__builtin_return_address(0); gh->gh_owner_pid = get_pid(task_pid(current)); gh->gh_state = state; gh->gh_flags = flags; gh->gh_error = 0; gh->gh_iflags = 0; gfs2_glock_hold(gl); } /** * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it * @state: the state we're requesting * @flags: the modifier flags * @gh: the holder structure * * Don't mess with the glock. * */ void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh) { gh->gh_state = state; gh->gh_flags = flags; gh->gh_iflags = 0; gh->gh_ip = (unsigned long)__builtin_return_address(0); } /** * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference) * @gh: the holder structure * */ void gfs2_holder_uninit(struct gfs2_holder *gh) { put_pid(gh->gh_owner_pid); gfs2_glock_put(gh->gh_gl); gh->gh_gl = NULL; gh->gh_ip = 0; } /** * gfs2_glock_holder_wait * @word: unused * * This function and gfs2_glock_demote_wait both show up in the WCHAN * field. Thus I've separated these otherwise identical functions in * order to be more informative to the user. */ static int gfs2_glock_holder_wait(void *word) { schedule(); return 0; } static int gfs2_glock_demote_wait(void *word) { schedule(); return 0; } static void wait_on_holder(struct gfs2_holder *gh) { might_sleep(); wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE); } static void wait_on_demote(struct gfs2_glock *gl) { might_sleep(); wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE); } /** * handle_callback - process a demote request * @gl: the glock * @state: the state the caller wants us to change to * * There are only two requests that we are going to see in actual * practise: LM_ST_SHARED and LM_ST_UNLOCKED */ static void handle_callback(struct gfs2_glock *gl, unsigned int state, unsigned long delay) { int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE; set_bit(bit, &gl->gl_flags); if (gl->gl_demote_state == LM_ST_EXCLUSIVE) { gl->gl_demote_state = state; gl->gl_demote_time = jiffies; } else if (gl->gl_demote_state != LM_ST_UNLOCKED && gl->gl_demote_state != state) { gl->gl_demote_state = LM_ST_UNLOCKED; } if (gl->gl_ops->go_callback) gl->gl_ops->go_callback(gl); trace_gfs2_demote_rq(gl); } /** * gfs2_glock_wait - wait on a glock acquisition * @gh: the glock holder * * Returns: 0 on success */ int gfs2_glock_wait(struct gfs2_holder *gh) { wait_on_holder(gh); return gh->gh_error; } void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...) { va_list args; va_start(args, fmt); if (seq) { struct gfs2_glock_iter *gi = seq->private; vsprintf(gi->string, fmt, args); seq_printf(seq, gi->string); } else { printk(KERN_ERR " "); vprintk(fmt, args); } va_end(args); } /** * add_to_queue - Add a holder to the wait queue (but look for recursion) * @gh: the holder structure to add * * Eventually we should move the recursive locking trap to a * debugging option or something like that. This is the fast * path and needs to have the minimum number of distractions. * */ static inline void add_to_queue(struct gfs2_holder *gh) __releases(&gl->gl_spin) __acquires(&gl->gl_spin) { struct gfs2_glock *gl = gh->gh_gl; struct gfs2_sbd *sdp = gl->gl_sbd; struct list_head *insert_pt = NULL; struct gfs2_holder *gh2; int try_lock = 0; BUG_ON(gh->gh_owner_pid == NULL); if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags)) BUG(); if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) { if (test_bit(GLF_LOCK, &gl->gl_flags)) try_lock = 1; if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) goto fail; } list_for_each_entry(gh2, &gl->gl_holders, gh_list) { if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid && (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK))) goto trap_recursive; if (try_lock && !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) && !may_grant(gl, gh)) { fail: gh->gh_error = GLR_TRYFAILED; gfs2_holder_wake(gh); return; } if (test_bit(HIF_HOLDER, &gh2->gh_iflags)) continue; if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt)) insert_pt = &gh2->gh_list; } if (likely(insert_pt == NULL)) { list_add_tail(&gh->gh_list, &gl->gl_holders); if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY)) goto do_cancel; return; } trace_gfs2_glock_queue(gh, 1); list_add_tail(&gh->gh_list, insert_pt); do_cancel: gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list); if (!(gh->gh_flags & LM_FLAG_PRIORITY)) { spin_unlock(&gl->gl_spin); if (sdp->sd_lockstruct.ls_ops->lm_cancel) sdp->sd_lockstruct.ls_ops->lm_cancel(gl); spin_lock(&gl->gl_spin); } return; trap_recursive: print_symbol(KERN_ERR "original: %s\n", gh2->gh_ip); printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid)); printk(KERN_ERR "lock type: %d req lock state : %d\n", gh2->gh_gl->gl_name.ln_type, gh2->gh_state); print_symbol(KERN_ERR "new: %s\n", gh->gh_ip); printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid)); printk(KERN_ERR "lock type: %d req lock state : %d\n", gh->gh_gl->gl_name.ln_type, gh->gh_state); __dump_glock(NULL, gl); BUG(); } /** * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock) * @gh: the holder structure * * if (gh->gh_flags & GL_ASYNC), this never returns an error * * Returns: 0, GLR_TRYFAILED, or errno on failure */ int gfs2_glock_nq(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; struct gfs2_sbd *sdp = gl->gl_sbd; int error = 0; if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) return -EIO; spin_lock(&gl->gl_spin); add_to_queue(gh); run_queue(gl, 1); spin_unlock(&gl->gl_spin); if (!(gh->gh_flags & GL_ASYNC)) error = gfs2_glock_wait(gh); return error; } /** * gfs2_glock_poll - poll to see if an async request has been completed * @gh: the holder * * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on */ int gfs2_glock_poll(struct gfs2_holder *gh) { return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1; } /** * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock) * @gh: the glock holder * */ void gfs2_glock_dq(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; const struct gfs2_glock_operations *glops = gl->gl_ops; unsigned delay = 0; int fast_path = 0; spin_lock(&gl->gl_spin); if (gh->gh_flags & GL_NOCACHE) handle_callback(gl, LM_ST_UNLOCKED, 0); list_del_init(&gh->gh_list); if (find_first_holder(gl) == NULL) { if (glops->go_unlock) { GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags)); spin_unlock(&gl->gl_spin); glops->go_unlock(gh); spin_lock(&gl->gl_spin); clear_bit(GLF_LOCK, &gl->gl_flags); } if (list_empty(&gl->gl_holders) && !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && !test_bit(GLF_DEMOTE, &gl->gl_flags)) fast_path = 1; } trace_gfs2_glock_queue(gh, 0); spin_unlock(&gl->gl_spin); if (likely(fast_path)) return; gfs2_glock_hold(gl); if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) && !test_bit(GLF_DEMOTE, &gl->gl_flags)) delay = gl->gl_ops->go_min_hold_time; if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0) gfs2_glock_put(gl); } void gfs2_glock_dq_wait(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; gfs2_glock_dq(gh); wait_on_demote(gl); } /** * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it * @gh: the holder structure * */ void gfs2_glock_dq_uninit(struct gfs2_holder *gh) { gfs2_glock_dq(gh); gfs2_holder_uninit(gh); } /** * gfs2_glock_nq_num - acquire a glock based on lock number * @sdp: the filesystem * @number: the lock number * @glops: the glock operations for the type of glock * @state: the state to acquire the glock in * @flags: modifier flags for the aquisition * @gh: the struct gfs2_holder * * Returns: errno */ int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number, const struct gfs2_glock_operations *glops, unsigned int state, int flags, struct gfs2_holder *gh) { struct gfs2_glock *gl; int error; error = gfs2_glock_get(sdp, number, glops, CREATE, &gl); if (!error) { error = gfs2_glock_nq_init(gl, state, flags, gh); gfs2_glock_put(gl); } return error; } /** * glock_compare - Compare two struct gfs2_glock structures for sorting * @arg_a: the first structure * @arg_b: the second structure * */ static int glock_compare(const void *arg_a, const void *arg_b) { const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a; const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b; const struct lm_lockname *a = &gh_a->gh_gl->gl_name; const struct lm_lockname *b = &gh_b->gh_gl->gl_name; if (a->ln_number > b->ln_number) return 1; if (a->ln_number < b->ln_number) return -1; BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type); return 0; } /** * nq_m_sync - synchonously acquire more than one glock in deadlock free order * @num_gh: the number of structures * @ghs: an array of struct gfs2_holder structures * * Returns: 0 on success (all glocks acquired), * errno on failure (no glocks acquired) */ static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs, struct gfs2_holder **p) { unsigned int x; int error = 0; for (x = 0; x < num_gh; x++) p[x] = &ghs[x]; sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL); for (x = 0; x < num_gh; x++) { p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC); error = gfs2_glock_nq(p[x]); if (error) { while (x--) gfs2_glock_dq(p[x]); break; } } return error; } /** * gfs2_glock_nq_m - acquire multiple glocks * @num_gh: the number of structures * @ghs: an array of struct gfs2_holder structures * * * Returns: 0 on success (all glocks acquired), * errno on failure (no glocks acquired) */ int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs) { struct gfs2_holder *tmp[4]; struct gfs2_holder **pph = tmp; int error = 0; switch(num_gh) { case 0: return 0; case 1: ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC); return gfs2_glock_nq(ghs); default: if (num_gh <= 4) break; pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS); if (!pph) return -ENOMEM; } error = nq_m_sync(num_gh, ghs, pph); if (pph != tmp) kfree(pph); return error; } /** * gfs2_glock_dq_m - release multiple glocks * @num_gh: the number of structures * @ghs: an array of struct gfs2_holder structures * */ void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs) { unsigned int x; for (x = 0; x < num_gh; x++) gfs2_glock_dq(&ghs[x]); } /** * gfs2_glock_dq_uninit_m - release multiple glocks * @num_gh: the number of structures * @ghs: an array of struct gfs2_holder structures * */ void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs) { unsigned int x; for (x = 0; x < num_gh; x++) gfs2_glock_dq_uninit(&ghs[x]); } void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state) { unsigned long delay = 0; unsigned long holdtime; unsigned long now = jiffies; gfs2_glock_hold(gl); holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time; if (time_before(now, holdtime)) delay = holdtime - now; if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags)) delay = gl->gl_ops->go_min_hold_time; spin_lock(&gl->gl_spin); handle_callback(gl, state, delay); spin_unlock(&gl->gl_spin); if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0) gfs2_glock_put(gl); } /** * gfs2_glock_complete - Callback used by locking * @gl: Pointer to the glock * @ret: The return value from the dlm * */ void gfs2_glock_complete(struct gfs2_glock *gl, int ret) { struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct; gl->gl_reply = ret; if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_flags))) { struct gfs2_holder *gh; spin_lock(&gl->gl_spin); gh = find_first_waiter(gl); if ((!(gh && (gh->gh_flags & LM_FLAG_NOEXP)) && (gl->gl_target != LM_ST_UNLOCKED)) || ((ret & ~LM_OUT_ST_MASK) != 0)) set_bit(GLF_FROZEN, &gl->gl_flags); spin_unlock(&gl->gl_spin); if (test_bit(GLF_FROZEN, &gl->gl_flags)) return; } set_bit(GLF_REPLY_PENDING, &gl->gl_flags); gfs2_glock_hold(gl); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put(gl); } static int gfs2_shrink_glock_memory(int nr, gfp_t gfp_mask) { struct gfs2_glock *gl; int may_demote; int nr_skipped = 0; LIST_HEAD(skipped); if (nr == 0) goto out; if (!(gfp_mask & __GFP_FS)) return -1; spin_lock(&lru_lock); while(nr && !list_empty(&lru_list)) { gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru); list_del_init(&gl->gl_lru); atomic_dec(&lru_count); /* Test for being demotable */ if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) { gfs2_glock_hold(gl); spin_unlock(&lru_lock); spin_lock(&gl->gl_spin); may_demote = demote_ok(gl); if (may_demote) { handle_callback(gl, LM_ST_UNLOCKED, 0); nr--; } clear_bit(GLF_LOCK, &gl->gl_flags); smp_mb__after_clear_bit(); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put_nolock(gl); spin_unlock(&gl->gl_spin); spin_lock(&lru_lock); continue; } nr_skipped++; list_add(&gl->gl_lru, &skipped); } list_splice(&skipped, &lru_list); atomic_add(nr_skipped, &lru_count); spin_unlock(&lru_lock); out: return (atomic_read(&lru_count) / 100) * sysctl_vfs_cache_pressure; } static struct shrinker glock_shrinker = { .shrink = gfs2_shrink_glock_memory, .seeks = DEFAULT_SEEKS, }; /** * examine_bucket - Call a function for glock in a hash bucket * @examiner: the function * @sdp: the filesystem * @bucket: the bucket * * Returns: 1 if the bucket has entries */ static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp, unsigned int hash) { struct gfs2_glock *gl, *prev = NULL; int has_entries = 0; struct hlist_head *head = &gl_hash_table[hash].hb_list; read_lock(gl_lock_addr(hash)); /* Can't use hlist_for_each_entry - don't want prefetch here */ if (hlist_empty(head)) goto out; gl = list_entry(head->first, struct gfs2_glock, gl_list); while(1) { if (!sdp || gl->gl_sbd == sdp) { gfs2_glock_hold(gl); read_unlock(gl_lock_addr(hash)); if (prev) gfs2_glock_put(prev); prev = gl; examiner(gl); has_entries = 1; read_lock(gl_lock_addr(hash)); } if (gl->gl_list.next == NULL) break; gl = list_entry(gl->gl_list.next, struct gfs2_glock, gl_list); } out: read_unlock(gl_lock_addr(hash)); if (prev) gfs2_glock_put(prev); cond_resched(); return has_entries; } /** * thaw_glock - thaw out a glock which has an unprocessed reply waiting * @gl: The glock to thaw * * N.B. When we freeze a glock, we leave a ref to the glock outstanding, * so this has to result in the ref count being dropped by one. */ static void thaw_glock(struct gfs2_glock *gl) { if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) return; set_bit(GLF_REPLY_PENDING, &gl->gl_flags); gfs2_glock_hold(gl); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put(gl); } /** * clear_glock - look at a glock and see if we can free it from glock cache * @gl: the glock to look at * */ static void clear_glock(struct gfs2_glock *gl) { spin_lock(&lru_lock); if (!list_empty(&gl->gl_lru)) { list_del_init(&gl->gl_lru); atomic_dec(&lru_count); } spin_unlock(&lru_lock); spin_lock(&gl->gl_spin); if (find_first_holder(gl) == NULL && gl->gl_state != LM_ST_UNLOCKED) handle_callback(gl, LM_ST_UNLOCKED, 0); spin_unlock(&gl->gl_spin); gfs2_glock_hold(gl); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put(gl); } /** * gfs2_glock_thaw - Thaw any frozen glocks * @sdp: The super block * */ void gfs2_glock_thaw(struct gfs2_sbd *sdp) { unsigned x; for (x = 0; x < GFS2_GL_HASH_SIZE; x++) examine_bucket(thaw_glock, sdp, x); } /** * gfs2_gl_hash_clear - Empty out the glock hash table * @sdp: the filesystem * @wait: wait until it's all gone * * Called when unmounting the filesystem. */ void gfs2_gl_hash_clear(struct gfs2_sbd *sdp) { unsigned long t; unsigned int x; int cont; t = jiffies; for (;;) { cont = 0; for (x = 0; x < GFS2_GL_HASH_SIZE; x++) { if (examine_bucket(clear_glock, sdp, x)) cont = 1; } if (!cont) break; if (time_after_eq(jiffies, t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) { fs_warn(sdp, "Unmount seems to be stalled. " "Dumping lock state...\n"); gfs2_dump_lockstate(sdp); t = jiffies; } down_write(&gfs2_umount_flush_sem); invalidate_inodes(sdp->sd_vfs); up_write(&gfs2_umount_flush_sem); msleep(10); } flush_workqueue(glock_workqueue); wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0); gfs2_dump_lockstate(sdp); } void gfs2_glock_finish_truncate(struct gfs2_inode *ip) { struct gfs2_glock *gl = ip->i_gl; int ret; ret = gfs2_truncatei_resume(ip); gfs2_assert_withdraw(gl->gl_sbd, ret == 0); spin_lock(&gl->gl_spin); clear_bit(GLF_LOCK, &gl->gl_flags); run_queue(gl, 1); spin_unlock(&gl->gl_spin); } static const char *state2str(unsigned state) { switch(state) { case LM_ST_UNLOCKED: return "UN"; case LM_ST_SHARED: return "SH"; case LM_ST_DEFERRED: return "DF"; case LM_ST_EXCLUSIVE: return "EX"; } return "??"; } static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags) { char *p = buf; if (flags & LM_FLAG_TRY) *p++ = 't'; if (flags & LM_FLAG_TRY_1CB) *p++ = 'T'; if (flags & LM_FLAG_NOEXP) *p++ = 'e'; if (flags & LM_FLAG_ANY) *p++ = 'A'; if (flags & LM_FLAG_PRIORITY) *p++ = 'p'; if (flags & GL_ASYNC) *p++ = 'a'; if (flags & GL_EXACT) *p++ = 'E'; if (flags & GL_NOCACHE) *p++ = 'c'; if (test_bit(HIF_HOLDER, &iflags)) *p++ = 'H'; if (test_bit(HIF_WAIT, &iflags)) *p++ = 'W'; if (test_bit(HIF_FIRST, &iflags)) *p++ = 'F'; *p = 0; return buf; } /** * dump_holder - print information about a glock holder * @seq: the seq_file struct * @gh: the glock holder * * Returns: 0 on success, -ENOBUFS when we run out of space */ static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh) { struct task_struct *gh_owner = NULL; char buffer[KSYM_SYMBOL_LEN]; char flags_buf[32]; sprint_symbol(buffer, gh->gh_ip); if (gh->gh_owner_pid) gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID); gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %s\n", state2str(gh->gh_state), hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags), gh->gh_error, gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1, gh_owner ? gh_owner->comm : "(ended)", buffer); return 0; } static const char *gflags2str(char *buf, const unsigned long *gflags) { char *p = buf; if (test_bit(GLF_LOCK, gflags)) *p++ = 'l'; if (test_bit(GLF_DEMOTE, gflags)) *p++ = 'D'; if (test_bit(GLF_PENDING_DEMOTE, gflags)) *p++ = 'd'; if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags)) *p++ = 'p'; if (test_bit(GLF_DIRTY, gflags)) *p++ = 'y'; if (test_bit(GLF_LFLUSH, gflags)) *p++ = 'f'; if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags)) *p++ = 'i'; if (test_bit(GLF_REPLY_PENDING, gflags)) *p++ = 'r'; if (test_bit(GLF_INITIAL, gflags)) *p++ = 'I'; if (test_bit(GLF_FROZEN, gflags)) *p++ = 'F'; *p = 0; return buf; } /** * __dump_glock - print information about a glock * @seq: The seq_file struct * @gl: the glock * * The file format is as follows: * One line per object, capital letters are used to indicate objects * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented, * other objects are indented by a single space and follow the glock to * which they are related. Fields are indicated by lower case letters * followed by a colon and the field value, except for strings which are in * [] so that its possible to see if they are composed of spaces for * example. The field's are n = number (id of the object), f = flags, * t = type, s = state, r = refcount, e = error, p = pid. * * Returns: 0 on success, -ENOBUFS when we run out of space */ static int __dump_glock(struct seq_file *seq, const struct gfs2_glock *gl) { const struct gfs2_glock_operations *glops = gl->gl_ops; unsigned long long dtime; const struct gfs2_holder *gh; char gflags_buf[32]; int error = 0; dtime = jiffies - gl->gl_demote_time; dtime *= 1000000/HZ; /* demote time in uSec */ if (!test_bit(GLF_DEMOTE, &gl->gl_flags)) dtime = 0; gfs2_print_dbg(seq, "G: s:%s n:%u/%llu f:%s t:%s d:%s/%llu a:%d r:%d\n", state2str(gl->gl_state), gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number, gflags2str(gflags_buf, &gl->gl_flags), state2str(gl->gl_target), state2str(gl->gl_demote_state), dtime, atomic_read(&gl->gl_ail_count), atomic_read(&gl->gl_ref)); list_for_each_entry(gh, &gl->gl_holders, gh_list) { error = dump_holder(seq, gh); if (error) goto out; } if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump) error = glops->go_dump(seq, gl); out: return error; } static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl) { int ret; spin_lock(&gl->gl_spin); ret = __dump_glock(seq, gl); spin_unlock(&gl->gl_spin); return ret; } /** * gfs2_dump_lockstate - print out the current lockstate * @sdp: the filesystem * @ub: the buffer to copy the information into * * If @ub is NULL, dump the lockstate to the console. * */ static int gfs2_dump_lockstate(struct gfs2_sbd *sdp) { struct gfs2_glock *gl; struct hlist_node *h; unsigned int x; int error = 0; for (x = 0; x < GFS2_GL_HASH_SIZE; x++) { read_lock(gl_lock_addr(x)); hlist_for_each_entry(gl, h, &gl_hash_table[x].hb_list, gl_list) { if (gl->gl_sbd != sdp) continue; error = dump_glock(NULL, gl); if (error) break; } read_unlock(gl_lock_addr(x)); if (error) break; } return error; } int __init gfs2_glock_init(void) { unsigned i; for(i = 0; i < GFS2_GL_HASH_SIZE; i++) { INIT_HLIST_HEAD(&gl_hash_table[i].hb_list); } #ifdef GL_HASH_LOCK_SZ for(i = 0; i < GL_HASH_LOCK_SZ; i++) { rwlock_init(&gl_hash_locks[i]); } #endif glock_workqueue = create_workqueue("glock_workqueue"); if (IS_ERR(glock_workqueue)) return PTR_ERR(glock_workqueue); gfs2_delete_workqueue = create_workqueue("delete_workqueue"); if (IS_ERR(gfs2_delete_workqueue)) { destroy_workqueue(glock_workqueue); return PTR_ERR(gfs2_delete_workqueue); } register_shrinker(&glock_shrinker); return 0; } void gfs2_glock_exit(void) { unregister_shrinker(&glock_shrinker); destroy_workqueue(glock_workqueue); destroy_workqueue(gfs2_delete_workqueue); } static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi) { struct gfs2_glock *gl; restart: read_lock(gl_lock_addr(gi->hash)); gl = gi->gl; if (gl) { gi->gl = hlist_entry(gl->gl_list.next, struct gfs2_glock, gl_list); } else { gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first, struct gfs2_glock, gl_list); } if (gi->gl) gfs2_glock_hold(gi->gl); read_unlock(gl_lock_addr(gi->hash)); if (gl) gfs2_glock_put(gl); while (gi->gl == NULL) { gi->hash++; if (gi->hash >= GFS2_GL_HASH_SIZE) return 1; read_lock(gl_lock_addr(gi->hash)); gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first, struct gfs2_glock, gl_list); if (gi->gl) gfs2_glock_hold(gi->gl); read_unlock(gl_lock_addr(gi->hash)); } if (gi->sdp != gi->gl->gl_sbd) goto restart; return 0; } static void gfs2_glock_iter_free(struct gfs2_glock_iter *gi) { if (gi->gl) gfs2_glock_put(gi->gl); gi->gl = NULL; } static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos) { struct gfs2_glock_iter *gi = seq->private; loff_t n = *pos; gi->hash = 0; do { if (gfs2_glock_iter_next(gi)) { gfs2_glock_iter_free(gi); return NULL; } } while (n--); return gi->gl; } static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr, loff_t *pos) { struct gfs2_glock_iter *gi = seq->private; (*pos)++; if (gfs2_glock_iter_next(gi)) { gfs2_glock_iter_free(gi); return NULL; } return gi->gl; } static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr) { struct gfs2_glock_iter *gi = seq->private; gfs2_glock_iter_free(gi); } static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr) { return dump_glock(seq, iter_ptr); } static const struct seq_operations gfs2_glock_seq_ops = { .start = gfs2_glock_seq_start, .next = gfs2_glock_seq_next, .stop = gfs2_glock_seq_stop, .show = gfs2_glock_seq_show, }; static int gfs2_debugfs_open(struct inode *inode, struct file *file) { int ret = seq_open_private(file, &gfs2_glock_seq_ops, sizeof(struct gfs2_glock_iter)); if (ret == 0) { struct seq_file *seq = file->private_data; struct gfs2_glock_iter *gi = seq->private; gi->sdp = inode->i_private; } return ret; } static const struct file_operations gfs2_debug_fops = { .owner = THIS_MODULE, .open = gfs2_debugfs_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; int gfs2_create_debugfs_file(struct gfs2_sbd *sdp) { sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root); if (!sdp->debugfs_dir) return -ENOMEM; sdp->debugfs_dentry_glocks = debugfs_create_file("glocks", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp, &gfs2_debug_fops); if (!sdp->debugfs_dentry_glocks) return -ENOMEM; return 0; } void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp) { if (sdp && sdp->debugfs_dir) { if (sdp->debugfs_dentry_glocks) { debugfs_remove(sdp->debugfs_dentry_glocks); sdp->debugfs_dentry_glocks = NULL; } debugfs_remove(sdp->debugfs_dir); sdp->debugfs_dir = NULL; } } int gfs2_register_debugfs(void) { gfs2_root = debugfs_create_dir("gfs2", NULL); return gfs2_root ? 0 : -ENOMEM; } void gfs2_unregister_debugfs(void) { debugfs_remove(gfs2_root); gfs2_root = NULL; }