/* * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. * Copyright (C) 2004-2006 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 #include #include "gfs2.h" #include "incore.h" #include "glock.h" #include "glops.h" #include "inode.h" #include "lm.h" #include "lops.h" #include "meta_io.h" #include "quota.h" #include "super.h" #include "util.h" struct gfs2_gl_hash_bucket { struct hlist_head hb_list; }; struct glock_iter { int hash; /* hash bucket index */ struct gfs2_sbd *sdp; /* incore superblock */ struct gfs2_glock *gl; /* current glock struct */ struct seq_file *seq; /* sequence file for debugfs */ 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 glock_iter *gi, struct gfs2_glock *gl); static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh); static void gfs2_glock_drop_th(struct gfs2_glock *gl); static void run_queue(struct gfs2_glock *gl); static DECLARE_RWSEM(gfs2_umount_flush_sem); static struct dentry *gfs2_root; static struct task_struct *scand_process; static unsigned int scand_secs = 5; static struct workqueue_struct *glock_workqueue; #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 /** * relaxed_state_ok - is a requested lock compatible with the current lock mode? * @actual: the current state of the lock * @requested: the lock state that was requested by the caller * @flags: the modifier flags passed in by the caller * * Returns: 1 if the locks are compatible, 0 otherwise */ static inline int relaxed_state_ok(unsigned int actual, unsigned requested, int flags) { if (actual == requested) return 1; if (flags & GL_EXACT) return 0; if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED) return 1; if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY)) return 1; return 0; } /** * 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 inode *aspace = gl->gl_aspace; gfs2_lm_put_lock(sdp, gl->gl_lock); if (aspace) gfs2_aspace_put(aspace); kmem_cache_free(gfs2_glock_cachep, gl); } /** * gfs2_glock_hold() - increment reference count on glock * @gl: The glock to hold * */ void gfs2_glock_hold(struct gfs2_glock *gl) { atomic_inc(&gl->gl_ref); } /** * gfs2_glock_put() - Decrement reference count on glock * @gl: The glock to put * */ int gfs2_glock_put(struct gfs2_glock *gl) { int rv = 0; struct gfs2_sbd *sdp = gl->gl_sbd; write_lock(gl_lock_addr(gl->gl_hash)); if (atomic_dec_and_test(&gl->gl_ref)) { hlist_del(&gl->gl_list); write_unlock(gl_lock_addr(gl->gl_hash)); BUG_ON(spin_is_locked(&gl->gl_spin)); gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED); gfs2_assert(sdp, list_empty(&gl->gl_reclaim)); gfs2_assert(sdp, list_empty(&gl->gl_holders)); gfs2_assert(sdp, list_empty(&gl->gl_waiters1)); gfs2_assert(sdp, list_empty(&gl->gl_waiters3)); glock_free(gl); rv = 1; goto out; } 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; } /** * gfs2_glock_find() - Find glock by lock number * @sdp: The GFS2 superblock * @name: The lock name * * Returns: NULL, or the struct gfs2_glock with the requested number */ static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp, const struct lm_lockname *name) { unsigned int hash = gl_hash(sdp, name); struct gfs2_glock *gl; read_lock(gl_lock_addr(hash)); gl = search_bucket(hash, sdp, name); read_unlock(gl_lock_addr(hash)); return gl; } static void glock_work_func(struct work_struct *work) { struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work); spin_lock(&gl->gl_spin); if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags)) set_bit(GLF_DEMOTE, &gl->gl_flags); run_queue(gl); spin_unlock(&gl->gl_spin); 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 lm_lockname name = { .ln_number = number, .ln_type = glops->go_type }; struct gfs2_glock *gl, *tmp; unsigned int hash = gl_hash(sdp, &name); int error; read_lock(gl_lock_addr(hash)); gl = search_bucket(hash, sdp, &name); read_unlock(gl_lock_addr(hash)); if (gl || !create) { *glp = gl; return 0; } gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL); if (!gl) return -ENOMEM; gl->gl_flags = 0; gl->gl_name = name; atomic_set(&gl->gl_ref, 1); gl->gl_state = LM_ST_UNLOCKED; gl->gl_demote_state = LM_ST_EXCLUSIVE; gl->gl_hash = hash; gl->gl_owner_pid = 0; gl->gl_ip = 0; gl->gl_ops = glops; gl->gl_req_gh = NULL; gl->gl_req_bh = NULL; gl->gl_vn = 0; gl->gl_stamp = jiffies; gl->gl_tchange = jiffies; gl->gl_object = NULL; gl->gl_sbd = sdp; gl->gl_aspace = NULL; lops_init_le(&gl->gl_le, &gfs2_glock_lops); INIT_DELAYED_WORK(&gl->gl_work, glock_work_func); /* If this glock protects actual on-disk data or metadata blocks, create a VFS inode to manage the pages/buffers holding them. */ if (glops == &gfs2_inode_glops || glops == &gfs2_rgrp_glops) { gl->gl_aspace = gfs2_aspace_get(sdp); if (!gl->gl_aspace) { error = -ENOMEM; goto fail; } } error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock); if (error) goto fail_aspace; 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; fail_aspace: if (gl->gl_aspace) gfs2_aspace_put(gl->gl_aspace); fail: kmem_cache_free(gfs2_glock_cachep, gl); return error; } /** * 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 = current->pid; 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) { gfs2_glock_put(gh->gh_gl); gh->gh_gl = NULL; gh->gh_ip = 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); } static int just_schedule(void *word) { schedule(); return 0; } static void wait_on_holder(struct gfs2_holder *gh) { might_sleep(); wait_on_bit(&gh->gh_iflags, HIF_WAIT, just_schedule, TASK_UNINTERRUPTIBLE); } static void gfs2_demote_wake(struct gfs2_glock *gl) { BUG_ON(!spin_is_locked(&gl->gl_spin)); 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); } static void wait_on_demote(struct gfs2_glock *gl) { might_sleep(); wait_on_bit(&gl->gl_flags, GLF_DEMOTE, just_schedule, TASK_UNINTERRUPTIBLE); } /** * rq_mutex - process a mutex request in the queue * @gh: the glock holder * * Returns: 1 if the queue is blocked */ static int rq_mutex(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; list_del_init(&gh->gh_list); /* gh->gh_error never examined. */ set_bit(GLF_LOCK, &gl->gl_flags); clear_bit(HIF_WAIT, &gh->gh_iflags); smp_mb(); wake_up_bit(&gh->gh_iflags, HIF_WAIT); return 1; } /** * rq_promote - process a promote request in the queue * @gh: the glock holder * * Acquire a new inter-node lock, or change a lock state to more restrictive. * * Returns: 1 if the queue is blocked */ static int rq_promote(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; struct gfs2_sbd *sdp = gl->gl_sbd; if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) { if (list_empty(&gl->gl_holders)) { gl->gl_req_gh = gh; set_bit(GLF_LOCK, &gl->gl_flags); spin_unlock(&gl->gl_spin); if (atomic_read(&sdp->sd_reclaim_count) > gfs2_tune_get(sdp, gt_reclaim_limit) && !(gh->gh_flags & LM_FLAG_PRIORITY)) { gfs2_reclaim_glock(sdp); gfs2_reclaim_glock(sdp); } gfs2_glock_xmote_th(gh->gh_gl, gh); spin_lock(&gl->gl_spin); } return 1; } if (list_empty(&gl->gl_holders)) { set_bit(HIF_FIRST, &gh->gh_iflags); set_bit(GLF_LOCK, &gl->gl_flags); } else { struct gfs2_holder *next_gh; if (gh->gh_state == LM_ST_EXCLUSIVE) return 1; next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list); if (next_gh->gh_state == LM_ST_EXCLUSIVE) return 1; } list_move_tail(&gh->gh_list, &gl->gl_holders); gh->gh_error = 0; set_bit(HIF_HOLDER, &gh->gh_iflags); gfs2_holder_wake(gh); return 0; } /** * rq_demote - process a demote request in the queue * @gh: the glock holder * * Returns: 1 if the queue is blocked */ static int rq_demote(struct gfs2_glock *gl) { if (!list_empty(&gl->gl_holders)) return 1; if (gl->gl_state == gl->gl_demote_state || gl->gl_state == LM_ST_UNLOCKED) { gfs2_demote_wake(gl); return 0; } set_bit(GLF_LOCK, &gl->gl_flags); if (gl->gl_demote_state == LM_ST_UNLOCKED || gl->gl_state != LM_ST_EXCLUSIVE) { spin_unlock(&gl->gl_spin); gfs2_glock_drop_th(gl); } else { spin_unlock(&gl->gl_spin); gfs2_glock_xmote_th(gl, NULL); } spin_lock(&gl->gl_spin); return 0; } /** * run_queue - process holder structures on a glock * @gl: the glock * */ static void run_queue(struct gfs2_glock *gl) { struct gfs2_holder *gh; int blocked = 1; for (;;) { if (test_bit(GLF_LOCK, &gl->gl_flags)) break; if (!list_empty(&gl->gl_waiters1)) { gh = list_entry(gl->gl_waiters1.next, struct gfs2_holder, gh_list); if (test_bit(HIF_MUTEX, &gh->gh_iflags)) blocked = rq_mutex(gh); else gfs2_assert_warn(gl->gl_sbd, 0); } else if (test_bit(GLF_DEMOTE, &gl->gl_flags)) { blocked = rq_demote(gl); } else if (!list_empty(&gl->gl_waiters3)) { gh = list_entry(gl->gl_waiters3.next, struct gfs2_holder, gh_list); if (test_bit(HIF_PROMOTE, &gh->gh_iflags)) blocked = rq_promote(gh); else gfs2_assert_warn(gl->gl_sbd, 0); } else break; if (blocked) break; } } /** * gfs2_glmutex_lock - acquire a local lock on a glock * @gl: the glock * * Gives caller exclusive access to manipulate a glock structure. */ static void gfs2_glmutex_lock(struct gfs2_glock *gl) { struct gfs2_holder gh; gfs2_holder_init(gl, 0, 0, &gh); set_bit(HIF_MUTEX, &gh.gh_iflags); if (test_and_set_bit(HIF_WAIT, &gh.gh_iflags)) BUG(); spin_lock(&gl->gl_spin); if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) { list_add_tail(&gh.gh_list, &gl->gl_waiters1); } else { gl->gl_owner_pid = current->pid; gl->gl_ip = (unsigned long)__builtin_return_address(0); clear_bit(HIF_WAIT, &gh.gh_iflags); smp_mb(); wake_up_bit(&gh.gh_iflags, HIF_WAIT); } spin_unlock(&gl->gl_spin); wait_on_holder(&gh); gfs2_holder_uninit(&gh); } /** * gfs2_glmutex_trylock - try to acquire a local lock on a glock * @gl: the glock * * Returns: 1 if the glock is acquired */ static int gfs2_glmutex_trylock(struct gfs2_glock *gl) { int acquired = 1; spin_lock(&gl->gl_spin); if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) { acquired = 0; } else { gl->gl_owner_pid = current->pid; gl->gl_ip = (unsigned long)__builtin_return_address(0); } spin_unlock(&gl->gl_spin); return acquired; } /** * gfs2_glmutex_unlock - release a local lock on a glock * @gl: the glock * */ static void gfs2_glmutex_unlock(struct gfs2_glock *gl) { spin_lock(&gl->gl_spin); clear_bit(GLF_LOCK, &gl->gl_flags); gl->gl_owner_pid = 0; gl->gl_ip = 0; run_queue(gl); BUG_ON(!spin_is_locked(&gl->gl_spin)); spin_unlock(&gl->gl_spin); } /** * 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, int remote, unsigned long delay) { int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE; spin_lock(&gl->gl_spin); set_bit(bit, &gl->gl_flags); if (gl->gl_demote_state == LM_ST_EXCLUSIVE) { gl->gl_demote_state = state; gl->gl_demote_time = jiffies; if (remote && gl->gl_ops->go_type == LM_TYPE_IOPEN && gl->gl_object) { struct inode *inode = igrab(gl->gl_object); spin_unlock(&gl->gl_spin); if (inode) { d_prune_aliases(inode); iput(inode); } return; } } else if (gl->gl_demote_state != LM_ST_UNLOCKED && gl->gl_demote_state != state) { gl->gl_demote_state = LM_ST_UNLOCKED; } spin_unlock(&gl->gl_spin); } /** * 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(gl); } gl->gl_state = new_state; gl->gl_tchange = jiffies; } /** * xmote_bh - Called after the lock module is done acquiring a lock * @gl: The glock in question * @ret: the int returned from the lock module * */ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret) { struct gfs2_sbd *sdp = gl->gl_sbd; const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_holder *gh = gl->gl_req_gh; int prev_state = gl->gl_state; int op_done = 1; gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags)); gfs2_assert_warn(sdp, list_empty(&gl->gl_holders)); gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC)); state_change(gl, ret & LM_OUT_ST_MASK); if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) { if (glops->go_inval) glops->go_inval(gl, DIO_METADATA); } else if (gl->gl_state == LM_ST_DEFERRED) { /* We might not want to do this here. Look at moving to the inode glops. */ if (glops->go_inval) glops->go_inval(gl, 0); } /* Deal with each possible exit condition */ if (!gh) { gl->gl_stamp = jiffies; if (ret & LM_OUT_CANCELED) { op_done = 0; } else { spin_lock(&gl->gl_spin); if (gl->gl_state != gl->gl_demote_state) { gl->gl_req_bh = NULL; spin_unlock(&gl->gl_spin); gfs2_glock_drop_th(gl); gfs2_glock_put(gl); return; } gfs2_demote_wake(gl); spin_unlock(&gl->gl_spin); } } else { spin_lock(&gl->gl_spin); list_del_init(&gh->gh_list); gh->gh_error = -EIO; if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) goto out; gh->gh_error = GLR_CANCELED; if (ret & LM_OUT_CANCELED) goto out; if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) { list_add_tail(&gh->gh_list, &gl->gl_holders); gh->gh_error = 0; set_bit(HIF_HOLDER, &gh->gh_iflags); set_bit(HIF_FIRST, &gh->gh_iflags); op_done = 0; goto out; } gh->gh_error = GLR_TRYFAILED; if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) goto out; gh->gh_error = -EINVAL; if (gfs2_assert_withdraw(sdp, 0) == -1) fs_err(sdp, "ret = 0x%.8X\n", ret); out: spin_unlock(&gl->gl_spin); } if (glops->go_xmote_bh) glops->go_xmote_bh(gl); if (op_done) { spin_lock(&gl->gl_spin); gl->gl_req_gh = NULL; gl->gl_req_bh = NULL; clear_bit(GLF_LOCK, &gl->gl_flags); spin_unlock(&gl->gl_spin); } gfs2_glock_put(gl); if (gh) gfs2_holder_wake(gh); } /** * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock * @gl: The glock in question * @state: the requested state * @flags: modifier flags to the lock call * */ static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh) { struct gfs2_sbd *sdp = gl->gl_sbd; int flags = gh ? gh->gh_flags : 0; unsigned state = gh ? gh->gh_state : gl->gl_demote_state; const struct gfs2_glock_operations *glops = gl->gl_ops; int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP | LM_FLAG_ANY | LM_FLAG_PRIORITY); unsigned int lck_ret; if (glops->go_xmote_th) glops->go_xmote_th(gl); gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags)); gfs2_assert_warn(sdp, list_empty(&gl->gl_holders)); gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED); gfs2_assert_warn(sdp, state != gl->gl_state); gfs2_glock_hold(gl); gl->gl_req_bh = xmote_bh; lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags); if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR))) return; if (lck_ret & LM_OUT_ASYNC) gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC); else xmote_bh(gl, lck_ret); } /** * drop_bh - Called after a lock module unlock completes * @gl: the glock * @ret: the return status * * Doesn't wake up the process waiting on the struct gfs2_holder (if any) * Doesn't drop the reference on the glock the top half took out * */ static void drop_bh(struct gfs2_glock *gl, unsigned int ret) { struct gfs2_sbd *sdp = gl->gl_sbd; const struct gfs2_glock_operations *glops = gl->gl_ops; struct gfs2_holder *gh = gl->gl_req_gh; gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags)); gfs2_assert_warn(sdp, list_empty(&gl->gl_holders)); gfs2_assert_warn(sdp, !ret); state_change(gl, LM_ST_UNLOCKED); if (glops->go_inval) glops->go_inval(gl, DIO_METADATA); if (gh) { spin_lock(&gl->gl_spin); list_del_init(&gh->gh_list); gh->gh_error = 0; spin_unlock(&gl->gl_spin); } spin_lock(&gl->gl_spin); gfs2_demote_wake(gl); gl->gl_req_gh = NULL; gl->gl_req_bh = NULL; clear_bit(GLF_LOCK, &gl->gl_flags); spin_unlock(&gl->gl_spin); gfs2_glock_put(gl); if (gh) gfs2_holder_wake(gh); } /** * gfs2_glock_drop_th - call into the lock module to unlock a lock * @gl: the glock * */ static void gfs2_glock_drop_th(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_sbd; const struct gfs2_glock_operations *glops = gl->gl_ops; unsigned int ret; if (glops->go_drop_th) glops->go_drop_th(gl); gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags)); gfs2_assert_warn(sdp, list_empty(&gl->gl_holders)); gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED); gfs2_glock_hold(gl); gl->gl_req_bh = drop_bh; ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state); if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR))) return; if (!ret) drop_bh(gl, ret); else gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC); } /** * do_cancels - cancel requests for locks stuck waiting on an expire flag * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock * * Don't cancel GL_NOCANCEL requests. */ static void do_cancels(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; spin_lock(&gl->gl_spin); while (gl->gl_req_gh != gh && !test_bit(HIF_HOLDER, &gh->gh_iflags) && !list_empty(&gh->gh_list)) { if (gl->gl_req_bh && !(gl->gl_req_gh && (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) { spin_unlock(&gl->gl_spin); gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock); msleep(100); spin_lock(&gl->gl_spin); } else { spin_unlock(&gl->gl_spin); msleep(100); spin_lock(&gl->gl_spin); } } spin_unlock(&gl->gl_spin); } /** * glock_wait_internal - wait on a glock acquisition * @gh: the glock holder * * Returns: 0 on success */ static int glock_wait_internal(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; struct gfs2_sbd *sdp = gl->gl_sbd; const struct gfs2_glock_operations *glops = gl->gl_ops; if (test_bit(HIF_ABORTED, &gh->gh_iflags)) return -EIO; if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) { spin_lock(&gl->gl_spin); if (gl->gl_req_gh != gh && !test_bit(HIF_HOLDER, &gh->gh_iflags) && !list_empty(&gh->gh_list)) { list_del_init(&gh->gh_list); gh->gh_error = GLR_TRYFAILED; run_queue(gl); spin_unlock(&gl->gl_spin); return gh->gh_error; } spin_unlock(&gl->gl_spin); } if (gh->gh_flags & LM_FLAG_PRIORITY) do_cancels(gh); wait_on_holder(gh); if (gh->gh_error) return gh->gh_error; gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags)); gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)); if (test_bit(HIF_FIRST, &gh->gh_iflags)) { gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags)); if (glops->go_lock) { gh->gh_error = glops->go_lock(gh); if (gh->gh_error) { spin_lock(&gl->gl_spin); list_del_init(&gh->gh_list); spin_unlock(&gl->gl_spin); } } spin_lock(&gl->gl_spin); gl->gl_req_gh = NULL; gl->gl_req_bh = NULL; clear_bit(GLF_LOCK, &gl->gl_flags); run_queue(gl); spin_unlock(&gl->gl_spin); } return gh->gh_error; } static inline struct gfs2_holder * find_holder_by_owner(struct list_head *head, pid_t pid) { struct gfs2_holder *gh; list_for_each_entry(gh, head, gh_list) { if (gh->gh_owner_pid == pid) return gh; } return NULL; } static void print_dbg(struct glock_iter *gi, const char *fmt, ...) { va_list args; va_start(args, fmt); if (gi) { vsprintf(gi->string, fmt, args); seq_printf(gi->seq, gi->string); } else 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 * */ static void add_to_queue(struct gfs2_holder *gh) { struct gfs2_glock *gl = gh->gh_gl; struct gfs2_holder *existing; BUG_ON(!gh->gh_owner_pid); if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags)) BUG(); if (!(gh->gh_flags & GL_FLOCK)) { existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner_pid); if (existing) { print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip); printk(KERN_INFO "pid : %d\n", existing->gh_owner_pid); printk(KERN_INFO "lock type : %d lock state : %d\n", existing->gh_gl->gl_name.ln_type, existing->gh_gl->gl_state); print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip); printk(KERN_INFO "pid : %d\n", gh->gh_owner_pid); printk(KERN_INFO "lock type : %d lock state : %d\n", gl->gl_name.ln_type, gl->gl_state); BUG(); } existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner_pid); if (existing) { print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip); print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip); BUG(); } } if (gh->gh_flags & LM_FLAG_PRIORITY) list_add(&gh->gh_list, &gl->gl_waiters3); else list_add_tail(&gh->gh_list, &gl->gl_waiters3); } /** * 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; restart: if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) { set_bit(HIF_ABORTED, &gh->gh_iflags); return -EIO; } set_bit(HIF_PROMOTE, &gh->gh_iflags); spin_lock(&gl->gl_spin); add_to_queue(gh); run_queue(gl); spin_unlock(&gl->gl_spin); if (!(gh->gh_flags & GL_ASYNC)) { error = glock_wait_internal(gh); if (error == GLR_CANCELED) { msleep(100); goto restart; } } 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) { struct gfs2_glock *gl = gh->gh_gl; int ready = 0; spin_lock(&gl->gl_spin); if (test_bit(HIF_HOLDER, &gh->gh_iflags)) ready = 1; else if (list_empty(&gh->gh_list)) { if (gh->gh_error == GLR_CANCELED) { spin_unlock(&gl->gl_spin); msleep(100); if (gfs2_glock_nq(gh)) return 1; return 0; } else ready = 1; } spin_unlock(&gl->gl_spin); return ready; } /** * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC * @gh: the holder structure * * Returns: 0, GLR_TRYFAILED, or errno on failure */ int gfs2_glock_wait(struct gfs2_holder *gh) { int error; error = glock_wait_internal(gh); if (error == GLR_CANCELED) { msleep(100); gh->gh_flags &= ~GL_ASYNC; error = gfs2_glock_nq(gh); } return error; } /** * 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; if (gh->gh_flags & GL_NOCACHE) handle_callback(gl, LM_ST_UNLOCKED, 0, 0); gfs2_glmutex_lock(gl); spin_lock(&gl->gl_spin); list_del_init(&gh->gh_list); if (list_empty(&gl->gl_holders)) { spin_unlock(&gl->gl_spin); if (glops->go_unlock) glops->go_unlock(gh); spin_lock(&gl->gl_spin); gl->gl_stamp = jiffies; } clear_bit(GLF_LOCK, &gl->gl_flags); spin_unlock(&gl->gl_spin); 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]); } /** * gfs2_lvb_hold - attach a LVB from a glock * @gl: The glock in question * */ int gfs2_lvb_hold(struct gfs2_glock *gl) { int error; gfs2_glmutex_lock(gl); if (!atomic_read(&gl->gl_lvb_count)) { error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb); if (error) { gfs2_glmutex_unlock(gl); return error; } gfs2_glock_hold(gl); } atomic_inc(&gl->gl_lvb_count); gfs2_glmutex_unlock(gl); return 0; } /** * gfs2_lvb_unhold - detach a LVB from a glock * @gl: The glock in question * */ void gfs2_lvb_unhold(struct gfs2_glock *gl) { gfs2_glock_hold(gl); gfs2_glmutex_lock(gl); gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0); if (atomic_dec_and_test(&gl->gl_lvb_count)) { gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb); gl->gl_lvb = NULL; gfs2_glock_put(gl); } gfs2_glmutex_unlock(gl); gfs2_glock_put(gl); } static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name, unsigned int state) { struct gfs2_glock *gl; unsigned long delay = 0; unsigned long holdtime; unsigned long now = jiffies; gl = gfs2_glock_find(sdp, name); if (!gl) return; holdtime = gl->gl_tchange + gl->gl_ops->go_min_hold_time; if (time_before(now, holdtime)) delay = holdtime - now; handle_callback(gl, state, 1, delay); if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0) gfs2_glock_put(gl); } /** * gfs2_glock_cb - Callback used by locking module * @sdp: Pointer to the superblock * @type: Type of callback * @data: Type dependent data pointer * * Called by the locking module when it wants to tell us something. * Either we need to drop a lock, one of our ASYNC requests completed, or * a journal from another client needs to be recovered. */ void gfs2_glock_cb(void *cb_data, unsigned int type, void *data) { struct gfs2_sbd *sdp = cb_data; switch (type) { case LM_CB_NEED_E: blocking_cb(sdp, data, LM_ST_UNLOCKED); return; case LM_CB_NEED_D: blocking_cb(sdp, data, LM_ST_DEFERRED); return; case LM_CB_NEED_S: blocking_cb(sdp, data, LM_ST_SHARED); return; case LM_CB_ASYNC: { struct lm_async_cb *async = data; struct gfs2_glock *gl; down_read(&gfs2_umount_flush_sem); gl = gfs2_glock_find(sdp, &async->lc_name); if (gfs2_assert_warn(sdp, gl)) return; if (!gfs2_assert_warn(sdp, gl->gl_req_bh)) gl->gl_req_bh(gl, async->lc_ret); if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) gfs2_glock_put(gl); up_read(&gfs2_umount_flush_sem); return; } case LM_CB_NEED_RECOVERY: gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data); if (sdp->sd_recoverd_process) wake_up_process(sdp->sd_recoverd_process); return; case LM_CB_DROPLOCKS: gfs2_gl_hash_clear(sdp, NO_WAIT); gfs2_quota_scan(sdp); return; default: gfs2_assert_warn(sdp, 0); return; } } /** * 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(struct gfs2_glock *gl) { const struct gfs2_glock_operations *glops = gl->gl_ops; int demote = 1; if (test_bit(GLF_STICKY, &gl->gl_flags)) demote = 0; else if (glops->go_demote_ok) demote = glops->go_demote_ok(gl); return demote; } /** * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list * @gl: the glock * */ void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_sbd; spin_lock(&sdp->sd_reclaim_lock); if (list_empty(&gl->gl_reclaim)) { gfs2_glock_hold(gl); list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list); atomic_inc(&sdp->sd_reclaim_count); } spin_unlock(&sdp->sd_reclaim_lock); wake_up(&sdp->sd_reclaim_wq); } /** * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list * @sdp: the filesystem * * Called from gfs2_glockd() glock reclaim daemon, or when promoting a * different glock and we notice that there are a lot of glocks in the * reclaim list. * */ void gfs2_reclaim_glock(struct gfs2_sbd *sdp) { struct gfs2_glock *gl; spin_lock(&sdp->sd_reclaim_lock); if (list_empty(&sdp->sd_reclaim_list)) { spin_unlock(&sdp->sd_reclaim_lock); return; } gl = list_entry(sdp->sd_reclaim_list.next, struct gfs2_glock, gl_reclaim); list_del_init(&gl->gl_reclaim); spin_unlock(&sdp->sd_reclaim_lock); atomic_dec(&sdp->sd_reclaim_count); atomic_inc(&sdp->sd_reclaimed); if (gfs2_glmutex_trylock(gl)) { if (list_empty(&gl->gl_holders) && gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl)) handle_callback(gl, LM_ST_UNLOCKED, 0, 0); gfs2_glmutex_unlock(gl); } gfs2_glock_put(gl); } /** * 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; } /** * scan_glock - look at a glock and see if we can reclaim it * @gl: the glock to look at * */ static void scan_glock(struct gfs2_glock *gl) { if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) return; if (gfs2_glmutex_trylock(gl)) { if (list_empty(&gl->gl_holders) && gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl)) goto out_schedule; gfs2_glmutex_unlock(gl); } return; out_schedule: gfs2_glmutex_unlock(gl); gfs2_glock_schedule_for_reclaim(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) { struct gfs2_sbd *sdp = gl->gl_sbd; int released; spin_lock(&sdp->sd_reclaim_lock); if (!list_empty(&gl->gl_reclaim)) { list_del_init(&gl->gl_reclaim); atomic_dec(&sdp->sd_reclaim_count); spin_unlock(&sdp->sd_reclaim_lock); released = gfs2_glock_put(gl); gfs2_assert(sdp, !released); } else { spin_unlock(&sdp->sd_reclaim_lock); } if (gfs2_glmutex_trylock(gl)) { if (list_empty(&gl->gl_holders) && gl->gl_state != LM_ST_UNLOCKED) handle_callback(gl, LM_ST_UNLOCKED, 0, 0); gfs2_glmutex_unlock(gl); } } /** * 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, or when inter-node lock manager * requests DROPLOCKS because it is running out of capacity. */ void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait) { 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 (!wait || !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); } } /* * Diagnostic routines to help debug distributed deadlock */ static void gfs2_print_symbol(struct glock_iter *gi, const char *fmt, unsigned long address) { char buffer[KSYM_SYMBOL_LEN]; sprint_symbol(buffer, address); print_dbg(gi, fmt, buffer); } /** * dump_holder - print information about a glock holder * @str: a string naming the type of holder * @gh: the glock holder * * Returns: 0 on success, -ENOBUFS when we run out of space */ static int dump_holder(struct glock_iter *gi, char *str, struct gfs2_holder *gh) { unsigned int x; struct task_struct *gh_owner; print_dbg(gi, " %s\n", str); if (gh->gh_owner_pid) { print_dbg(gi, " owner = %ld ", (long)gh->gh_owner_pid); gh_owner = find_task_by_pid(gh->gh_owner_pid); if (gh_owner) print_dbg(gi, "(%s)\n", gh_owner->comm); else print_dbg(gi, "(ended)\n"); } else print_dbg(gi, " owner = -1\n"); print_dbg(gi, " gh_state = %u\n", gh->gh_state); print_dbg(gi, " gh_flags ="); for (x = 0; x < 32; x++) if (gh->gh_flags & (1 << x)) print_dbg(gi, " %u", x); print_dbg(gi, " \n"); print_dbg(gi, " error = %d\n", gh->gh_error); print_dbg(gi, " gh_iflags ="); for (x = 0; x < 32; x++) if (test_bit(x, &gh->gh_iflags)) print_dbg(gi, " %u", x); print_dbg(gi, " \n"); gfs2_print_symbol(gi, " initialized at: %s\n", gh->gh_ip); return 0; } /** * dump_inode - print information about an inode * @ip: the inode * * Returns: 0 on success, -ENOBUFS when we run out of space */ static int dump_inode(struct glock_iter *gi, struct gfs2_inode *ip) { unsigned int x; print_dbg(gi, " Inode:\n"); print_dbg(gi, " num = %llu/%llu\n", (unsigned long long)ip->i_no_formal_ino, (unsigned long long)ip->i_no_addr); print_dbg(gi, " type = %u\n", IF2DT(ip->i_inode.i_mode)); print_dbg(gi, " i_flags ="); for (x = 0; x < 32; x++) if (test_bit(x, &ip->i_flags)) print_dbg(gi, " %u", x); print_dbg(gi, " \n"); return 0; } /** * dump_glock - print information about a glock * @gl: the glock * @count: where we are in the buffer * * Returns: 0 on success, -ENOBUFS when we run out of space */ static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl) { struct gfs2_holder *gh; unsigned int x; int error = -ENOBUFS; struct task_struct *gl_owner; spin_lock(&gl->gl_spin); print_dbg(gi, "Glock 0x%p (%u, 0x%llx)\n", gl, gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number); print_dbg(gi, " gl_flags ="); for (x = 0; x < 32; x++) { if (test_bit(x, &gl->gl_flags)) print_dbg(gi, " %u", x); } if (!test_bit(GLF_LOCK, &gl->gl_flags)) print_dbg(gi, " (unlocked)"); print_dbg(gi, " \n"); print_dbg(gi, " gl_ref = %d\n", atomic_read(&gl->gl_ref)); print_dbg(gi, " gl_state = %u\n", gl->gl_state); if (gl->gl_owner_pid) { gl_owner = find_task_by_pid(gl->gl_owner_pid); if (gl_owner) print_dbg(gi, " gl_owner = pid %d (%s)\n", gl->gl_owner_pid, gl_owner->comm); else print_dbg(gi, " gl_owner = %d (ended)\n", gl->gl_owner_pid); } else print_dbg(gi, " gl_owner = -1\n"); print_dbg(gi, " gl_ip = %lu\n", gl->gl_ip); print_dbg(gi, " req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no"); print_dbg(gi, " req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no"); print_dbg(gi, " lvb_count = %d\n", atomic_read(&gl->gl_lvb_count)); print_dbg(gi, " object = %s\n", (gl->gl_object) ? "yes" : "no"); print_dbg(gi, " le = %s\n", (list_empty(&gl->gl_le.le_list)) ? "no" : "yes"); print_dbg(gi, " reclaim = %s\n", (list_empty(&gl->gl_reclaim)) ? "no" : "yes"); if (gl->gl_aspace) print_dbg(gi, " aspace = 0x%p nrpages = %lu\n", gl->gl_aspace, gl->gl_aspace->i_mapping->nrpages); else print_dbg(gi, " aspace = no\n"); print_dbg(gi, " ail = %d\n", atomic_read(&gl->gl_ail_count)); if (gl->gl_req_gh) { error = dump_holder(gi, "Request", gl->gl_req_gh); if (error) goto out; } list_for_each_entry(gh, &gl->gl_holders, gh_list) { error = dump_holder(gi, "Holder", gh); if (error) goto out; } list_for_each_entry(gh, &gl->gl_waiters1, gh_list) { error = dump_holder(gi, "Waiter1", gh); if (error) goto out; } list_for_each_entry(gh, &gl->gl_waiters3, gh_list) { error = dump_holder(gi, "Waiter3", gh); if (error) goto out; } if (test_bit(GLF_DEMOTE, &gl->gl_flags)) { print_dbg(gi, " Demotion req to state %u (%llu uS ago)\n", gl->gl_demote_state, (unsigned long long) (jiffies - gl->gl_demote_time)*(1000000/HZ)); } if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) { if (!test_bit(GLF_LOCK, &gl->gl_flags) && list_empty(&gl->gl_holders)) { error = dump_inode(gi, gl->gl_object); if (error) goto out; } else { error = -ENOBUFS; print_dbg(gi, " Inode: busy\n"); } } error = 0; out: spin_unlock(&gl->gl_spin); return error; } /** * 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; } /** * gfs2_scand - Look for cached glocks and inodes to toss from memory * @sdp: Pointer to GFS2 superblock * * One of these daemons runs, finding candidates to add to sd_reclaim_list. * See gfs2_glockd() */ static int gfs2_scand(void *data) { unsigned x; unsigned delay; while (!kthread_should_stop()) { for (x = 0; x < GFS2_GL_HASH_SIZE; x++) examine_bucket(scan_glock, NULL, x); if (freezing(current)) refrigerator(); delay = scand_secs; if (delay < 1) delay = 1; schedule_timeout_interruptible(delay * HZ); } return 0; } 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 scand_process = kthread_run(gfs2_scand, NULL, "gfs2_scand"); if (IS_ERR(scand_process)) return PTR_ERR(scand_process); glock_workqueue = create_workqueue("glock_workqueue"); if (IS_ERR(glock_workqueue)) { kthread_stop(scand_process); return PTR_ERR(glock_workqueue); } return 0; } void gfs2_glock_exit(void) { destroy_workqueue(glock_workqueue); kthread_stop(scand_process); } module_param(scand_secs, uint, S_IRUGO|S_IWUSR); MODULE_PARM_DESC(scand_secs, "The number of seconds between scand runs"); static int gfs2_glock_iter_next(struct 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); if (gi->gl) gfs2_glock_hold(gi->gl); } read_unlock(gl_lock_addr(gi->hash)); if (gl) gfs2_glock_put(gl); if (gl && gi->gl == NULL) gi->hash++; while(gi->gl == NULL) { 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)); gi->hash++; } if (gi->sdp != gi->gl->gl_sbd) goto restart; return 0; } static void gfs2_glock_iter_free(struct glock_iter *gi) { if (gi->gl) gfs2_glock_put(gi->gl); kfree(gi); } static struct glock_iter *gfs2_glock_iter_init(struct gfs2_sbd *sdp) { struct glock_iter *gi; gi = kmalloc(sizeof (*gi), GFP_KERNEL); if (!gi) return NULL; gi->sdp = sdp; gi->hash = 0; gi->seq = NULL; gi->gl = NULL; memset(gi->string, 0, sizeof(gi->string)); if (gfs2_glock_iter_next(gi)) { gfs2_glock_iter_free(gi); return NULL; } return gi; } static void *gfs2_glock_seq_start(struct seq_file *file, loff_t *pos) { struct glock_iter *gi; loff_t n = *pos; gi = gfs2_glock_iter_init(file->private); if (!gi) return NULL; while(n--) { if (gfs2_glock_iter_next(gi)) { gfs2_glock_iter_free(gi); return NULL; } } return gi; } static void *gfs2_glock_seq_next(struct seq_file *file, void *iter_ptr, loff_t *pos) { struct glock_iter *gi = iter_ptr; (*pos)++; if (gfs2_glock_iter_next(gi)) { gfs2_glock_iter_free(gi); return NULL; } return gi; } static void gfs2_glock_seq_stop(struct seq_file *file, void *iter_ptr) { struct glock_iter *gi = iter_ptr; if (gi) gfs2_glock_iter_free(gi); } static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr) { struct glock_iter *gi = iter_ptr; gi->seq = file; dump_glock(gi, gi->gl); return 0; } 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) { struct seq_file *seq; int ret; ret = seq_open(file, &gfs2_glock_seq_ops); if (ret) return ret; seq = file->private_data; seq->private = inode->i_private; return 0; } static const struct file_operations gfs2_debug_fops = { .owner = THIS_MODULE, .open = gfs2_debugfs_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release }; 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; }