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SubjectGFS2 Filesystem [2/16]
From
Date
[PATCH 02/16] GFS2: 

The core GFS2 locking code, including the interface to the pluggable
locking modules.



Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>


fs/gfs2/glock.c | 2492 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/gfs2/glock.h | 143 ++
fs/gfs2/lm.c | 235 ++++
fs/gfs2/lm.h | 42
fs/gfs2/lm_interface.h | 295 +++++
fs/gfs2/locking.c | 192 +++
6 files changed, 3399 insertions(+)
--- /dev/null
+++ b/fs/gfs2/lm.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/delay.h>
+#include <asm/semaphore.h>
+
+#include "gfs2.h"
+#include "glock.h"
+#include "lm.h"
+#include "super.h"
+
+/**
+ * gfs2_lm_mount - mount a locking protocol
+ * @sdp: the filesystem
+ * @args: mount arguements
+ * @silent: if 1, don't complain if the FS isn't a GFS2 fs
+ *
+ * Returns: errno
+ */
+
+int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent)
+{
+ char *proto = sdp->sd_proto_name;
+ char *table = sdp->sd_table_name;
+ int flags = 0;
+ int error;
+
+ if (sdp->sd_args.ar_spectator)
+ flags |= LM_MFLAG_SPECTATOR;
+
+ fs_info(sdp, "Trying to join cluster \"%s\", \"%s\"\n", proto, table);
+
+ error = gfs2_mount_lockproto(proto, table, sdp->sd_args.ar_hostdata,
+ gfs2_glock_cb, sdp,
+ GFS2_MIN_LVB_SIZE, flags,
+ &sdp->sd_lockstruct, &sdp->sd_kobj);
+ if (error) {
+ fs_info(sdp, "can't mount proto=%s, table=%s, hostdata=%s\n",
+ proto, table, sdp->sd_args.ar_hostdata);
+ goto out;
+ }
+
+ if (gfs2_assert_warn(sdp, sdp->sd_lockstruct.ls_lockspace) ||
+ gfs2_assert_warn(sdp, sdp->sd_lockstruct.ls_ops) ||
+ gfs2_assert_warn(sdp, sdp->sd_lockstruct.ls_lvb_size >=
+ GFS2_MIN_LVB_SIZE)) {
+ gfs2_unmount_lockproto(&sdp->sd_lockstruct);
+ goto out;
+ }
+
+ if (sdp->sd_args.ar_spectator)
+ snprintf(sdp->sd_fsname, GFS2_FSNAME_LEN, "%s.s", table);
+ else
+ snprintf(sdp->sd_fsname, GFS2_FSNAME_LEN, "%s.%u", table,
+ sdp->sd_lockstruct.ls_jid);
+
+ fs_info(sdp, "Joined cluster. Now mounting FS...\n");
+
+ if ((sdp->sd_lockstruct.ls_flags & LM_LSFLAG_LOCAL) &&
+ !sdp->sd_args.ar_ignore_local_fs) {
+ sdp->sd_args.ar_localflocks = 1;
+ sdp->sd_args.ar_localcaching = 1;
+ }
+
+ out:
+ return error;
+}
+
+void gfs2_lm_others_may_mount(struct gfs2_sbd *sdp)
+{
+ if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ sdp->sd_lockstruct.ls_ops->lm_others_may_mount(sdp->sd_lockstruct.ls_lockspace);
+}
+
+void gfs2_lm_unmount(struct gfs2_sbd *sdp)
+{
+ if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ gfs2_unmount_lockproto(&sdp->sd_lockstruct);
+}
+
+int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
+{
+ va_list args;
+
+ if (test_and_set_bit(SDF_SHUTDOWN, &sdp->sd_flags))
+ return 0;
+
+ va_start(args, fmt);
+ vprintk(fmt, args);
+ va_end(args);
+
+ fs_err(sdp, "about to withdraw from the cluster\n");
+ if (sdp->sd_args.ar_debug)
+ BUG();
+
+ fs_err(sdp, "waiting for outstanding I/O\n");
+
+ /* FIXME: suspend dm device so oustanding bio's complete
+ and all further io requests fail */
+
+ fs_err(sdp, "telling LM to withdraw\n");
+ gfs2_withdraw_lockproto(&sdp->sd_lockstruct);
+ fs_err(sdp, "withdrawn\n");
+ dump_stack();
+
+ return -1;
+}
+
+int gfs2_lm_get_lock(struct gfs2_sbd *sdp, struct lm_lockname *name,
+ lm_lock_t **lockp)
+{
+ int error;
+ if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ error = -EIO;
+ else
+ error = sdp->sd_lockstruct.ls_ops->lm_get_lock(sdp->sd_lockstruct.ls_lockspace, name, lockp);
+ return error;
+}
+
+void gfs2_lm_put_lock(struct gfs2_sbd *sdp, lm_lock_t *lock)
+{
+ if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ sdp->sd_lockstruct.ls_ops->lm_put_lock(lock);
+}
+
+unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, lm_lock_t *lock,
+ unsigned int cur_state, unsigned int req_state,
+ unsigned int flags)
+{
+ int ret;
+ if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ ret = 0;
+ else
+ ret = sdp->sd_lockstruct.ls_ops->lm_lock(lock,
+ cur_state,
+ req_state, flags);
+ return ret;
+}
+
+unsigned int gfs2_lm_unlock(struct gfs2_sbd *sdp, lm_lock_t *lock,
+ unsigned int cur_state)
+{
+ int ret;
+ if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ ret = 0;
+ else
+ ret = sdp->sd_lockstruct.ls_ops->lm_unlock(lock, cur_state);
+ return ret;
+}
+
+void gfs2_lm_cancel(struct gfs2_sbd *sdp, lm_lock_t *lock)
+{
+ if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ sdp->sd_lockstruct.ls_ops->lm_cancel(lock);
+}
+
+int gfs2_lm_hold_lvb(struct gfs2_sbd *sdp, lm_lock_t *lock, char **lvbp)
+{
+ int error;
+ if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ error = -EIO;
+ else
+ error = sdp->sd_lockstruct.ls_ops->lm_hold_lvb(lock, lvbp);
+ return error;
+}
+
+void gfs2_lm_unhold_lvb(struct gfs2_sbd *sdp, lm_lock_t *lock, char *lvb)
+{
+ if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ sdp->sd_lockstruct.ls_ops->lm_unhold_lvb(lock, lvb);
+}
+
+void gfs2_lm_sync_lvb(struct gfs2_sbd *sdp, lm_lock_t *lock, char *lvb)
+{
+ if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ sdp->sd_lockstruct.ls_ops->lm_sync_lvb(lock, lvb);
+}
+
+int gfs2_lm_plock_get(struct gfs2_sbd *sdp, struct lm_lockname *name,
+ struct file *file, struct file_lock *fl)
+{
+ int error;
+ if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ error = -EIO;
+ else
+ error = sdp->sd_lockstruct.ls_ops->lm_plock_get(
+ sdp->sd_lockstruct.ls_lockspace,
+ name, file, fl);
+ return error;
+}
+
+int gfs2_lm_plock(struct gfs2_sbd *sdp, struct lm_lockname *name,
+ struct file *file, int cmd, struct file_lock *fl)
+{
+ int error;
+ if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ error = -EIO;
+ else
+ error = sdp->sd_lockstruct.ls_ops->lm_plock(
+ sdp->sd_lockstruct.ls_lockspace,
+ name, file, cmd, fl);
+ return error;
+}
+
+int gfs2_lm_punlock(struct gfs2_sbd *sdp, struct lm_lockname *name,
+ struct file *file, struct file_lock *fl)
+{
+ int error;
+ if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ error = -EIO;
+ else
+ error = sdp->sd_lockstruct.ls_ops->lm_punlock(
+ sdp->sd_lockstruct.ls_lockspace,
+ name, file, fl);
+ return error;
+}
+
+void gfs2_lm_recovery_done(struct gfs2_sbd *sdp, unsigned int jid,
+ unsigned int message)
+{
+ if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+ sdp->sd_lockstruct.ls_ops->lm_recovery_done(sdp->sd_lockstruct.ls_lockspace, jid, message);
+}
+
--- /dev/null
+++ b/fs/gfs2/lm.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#ifndef __LM_DOT_H__
+#define __LM_DOT_H__
+
+int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent);
+void gfs2_lm_others_may_mount(struct gfs2_sbd *sdp);
+void gfs2_lm_unmount(struct gfs2_sbd *sdp);
+int gfs2_lm_withdraw(struct gfs2_sbd *sdp, char *fmt, ...)
+__attribute__ ((format(printf, 2, 3)));
+int gfs2_lm_get_lock(struct gfs2_sbd *sdp,
+ struct lm_lockname *name, lm_lock_t **lockp);
+void gfs2_lm_put_lock(struct gfs2_sbd *sdp, lm_lock_t *lock);
+unsigned int gfs2_lm_lock(struct gfs2_sbd *sdp, lm_lock_t *lock,
+ unsigned int cur_state, unsigned int req_state,
+ unsigned int flags);
+unsigned int gfs2_lm_unlock(struct gfs2_sbd *sdp, lm_lock_t *lock,
+ unsigned int cur_state);
+void gfs2_lm_cancel(struct gfs2_sbd *sdp, lm_lock_t *lock);
+int gfs2_lm_hold_lvb(struct gfs2_sbd *sdp, lm_lock_t *lock, char **lvbp);
+void gfs2_lm_unhold_lvb(struct gfs2_sbd *sdp, lm_lock_t *lock, char *lvb);
+void gfs2_lm_sync_lvb(struct gfs2_sbd *sdp, lm_lock_t *lock, char *lvb);
+int gfs2_lm_plock_get(struct gfs2_sbd *sdp,
+ struct lm_lockname *name,
+ struct file *file, struct file_lock *fl);
+int gfs2_lm_plock(struct gfs2_sbd *sdp,
+ struct lm_lockname *name,
+ struct file *file, int cmd, struct file_lock *fl);
+int gfs2_lm_punlock(struct gfs2_sbd *sdp,
+ struct lm_lockname *name,
+ struct file *file, struct file_lock *fl);
+void gfs2_lm_recovery_done(struct gfs2_sbd *sdp,
+ unsigned int jid, unsigned int message);
+
+#endif /* __LM_DOT_H__ */
--- /dev/null
+++ b/fs/gfs2/locking.c
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/kmod.h>
+#include <linux/fs.h>
+#include <linux/delay.h>
+
+#include "lm_interface.h"
+
+struct lmh_wrapper {
+ struct list_head lw_list;
+ struct lm_lockops *lw_ops;
+};
+
+/* List of registered low-level locking protocols. A file system selects one
+ of them by name at mount time, e.g. lock_nolock, lock_dlm. */
+
+static struct list_head lmh_list;
+static struct semaphore lmh_lock;
+
+/**
+ * gfs_register_lockproto - Register a low-level locking protocol
+ * @proto: the protocol definition
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+int gfs_register_lockproto(struct lm_lockops *proto)
+{
+ struct lmh_wrapper *lw;
+
+ down(&lmh_lock);
+
+ list_for_each_entry(lw, &lmh_list, lw_list) {
+ if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
+ up(&lmh_lock);
+ printk("GFS2: protocol %s already exists\n",
+ proto->lm_proto_name);
+ return -EEXIST;
+ }
+ }
+
+ lw = kmalloc(sizeof(struct lmh_wrapper), GFP_KERNEL);
+ if (!lw) {
+ up(&lmh_lock);
+ return -ENOMEM;
+ }
+ memset(lw, 0, sizeof(struct lmh_wrapper));
+
+ lw->lw_ops = proto;
+ list_add(&lw->lw_list, &lmh_list);
+
+ up(&lmh_lock);
+
+ return 0;
+}
+
+/**
+ * gfs_unregister_lockproto - Unregister a low-level locking protocol
+ * @proto: the protocol definition
+ *
+ */
+
+void gfs_unregister_lockproto(struct lm_lockops *proto)
+{
+ struct lmh_wrapper *lw;
+
+ down(&lmh_lock);
+
+ list_for_each_entry(lw, &lmh_list, lw_list) {
+ if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
+ list_del(&lw->lw_list);
+ up(&lmh_lock);
+ kfree(lw);
+ return;
+ }
+ }
+
+ up(&lmh_lock);
+
+ printk("GFS2: can't unregister lock protocol %s\n",
+ proto->lm_proto_name);
+}
+
+/**
+ * gfs2_mount_lockproto - Mount a lock protocol
+ * @proto_name - the name of the protocol
+ * @table_name - the name of the lock space
+ * @host_data - data specific to this host
+ * @cb - the callback to the code using the lock module
+ * @fsdata - data to pass back with the callback
+ * @min_lvb_size - the mininum LVB size that the caller can deal with
+ * @flags - LM_MFLAG_*
+ * @lockstruct - a structure returned describing the mount
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,
+ lm_callback_t cb, lm_fsdata_t *fsdata,
+ unsigned int min_lvb_size, int flags,
+ struct lm_lockstruct *lockstruct,
+ struct kobject *fskobj)
+{
+ struct lmh_wrapper *lw = NULL;
+ int try = 0;
+ int error, found;
+
+ retry:
+ down(&lmh_lock);
+
+ found = 0;
+ list_for_each_entry(lw, &lmh_list, lw_list) {
+ if (!strcmp(lw->lw_ops->lm_proto_name, proto_name)) {
+ found = 1;
+ break;
+ }
+ }
+
+ if (!found) {
+ if (!try && capable(CAP_SYS_MODULE)) {
+ try = 1;
+ up(&lmh_lock);
+ request_module(proto_name);
+ goto retry;
+ }
+ printk("GFS2: can't find protocol %s\n", proto_name);
+ error = -ENOENT;
+ goto out;
+ }
+
+ if (!try_module_get(lw->lw_ops->lm_owner)) {
+ try = 0;
+ up(&lmh_lock);
+ msleep(1000);
+ goto retry;
+ }
+
+ error = lw->lw_ops->lm_mount(table_name, host_data, cb, fsdata,
+ min_lvb_size, flags, lockstruct, fskobj);
+ if (error)
+ module_put(lw->lw_ops->lm_owner);
+ out:
+ up(&lmh_lock);
+ return error;
+}
+
+void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct)
+{
+ down(&lmh_lock);
+ lockstruct->ls_ops->lm_unmount(lockstruct->ls_lockspace);
+ if (lockstruct->ls_ops->lm_owner)
+ module_put(lockstruct->ls_ops->lm_owner);
+ up(&lmh_lock);
+}
+
+/**
+ * gfs2_withdraw_lockproto - abnormally unmount a lock module
+ * @lockstruct: the lockstruct passed into mount
+ *
+ */
+
+void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct)
+{
+ down(&lmh_lock);
+ lockstruct->ls_ops->lm_withdraw(lockstruct->ls_lockspace);
+ if (lockstruct->ls_ops->lm_owner)
+ module_put(lockstruct->ls_ops->lm_owner);
+ up(&lmh_lock);
+}
+
+void __init gfs2_init_lmh(void)
+{
+ init_MUTEX(&lmh_lock);
+ INIT_LIST_HEAD(&lmh_list);
+}
+
+EXPORT_SYMBOL_GPL(gfs_register_lockproto);
+EXPORT_SYMBOL_GPL(gfs_unregister_lockproto);
+
--- /dev/null
+++ b/fs/gfs2/lm_interface.h
@@ -0,0 +1,295 @@
+/*
+ * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#ifndef __LM_INTERFACE_DOT_H__
+#define __LM_INTERFACE_DOT_H__
+
+/*
+ * Opaque handles represent the lock module's lockspace structure, the lock
+ * module's lock structures, and GFS's file system (superblock) structure.
+ */
+
+typedef void lm_lockspace_t;
+typedef void lm_lock_t;
+typedef void lm_fsdata_t;
+
+typedef void (*lm_callback_t) (lm_fsdata_t *fsdata, unsigned int type,
+ void *data);
+
+/*
+ * lm_mount() flags
+ *
+ * LM_MFLAG_SPECTATOR
+ * GFS is asking to join the filesystem's lockspace, but it doesn't want to
+ * modify the filesystem. The lock module shouldn't assign a journal to the FS
+ * mount. It shouldn't send recovery callbacks to the FS mount. If the node
+ * dies or withdraws, all locks can be wiped immediately.
+ */
+
+#define LM_MFLAG_SPECTATOR 0x00000001
+
+/*
+ * lm_lockstruct flags
+ *
+ * LM_LSFLAG_LOCAL
+ * The lock_nolock module returns LM_LSFLAG_LOCAL to GFS, indicating that GFS
+ * can make single-node optimizations.
+ */
+
+#define LM_LSFLAG_LOCAL 0x00000001
+
+/*
+ * lm_lockname types
+ */
+
+#define LM_TYPE_RESERVED 0x00
+#define LM_TYPE_NONDISK 0x01
+#define LM_TYPE_INODE 0x02
+#define LM_TYPE_RGRP 0x03
+#define LM_TYPE_META 0x04
+#define LM_TYPE_IOPEN 0x05
+#define LM_TYPE_FLOCK 0x06
+#define LM_TYPE_PLOCK 0x07
+#define LM_TYPE_QUOTA 0x08
+#define LM_TYPE_JOURNAL 0x09
+
+/*
+ * lm_lock() states
+ *
+ * SHARED is compatible with SHARED, not with DEFERRED or EX.
+ * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
+ */
+
+#define LM_ST_UNLOCKED 0
+#define LM_ST_EXCLUSIVE 1
+#define LM_ST_DEFERRED 2
+#define LM_ST_SHARED 3
+
+/*
+ * lm_lock() flags
+ *
+ * LM_FLAG_TRY
+ * Don't wait to acquire the lock if it can't be granted immediately.
+ *
+ * LM_FLAG_TRY_1CB
+ * Send one blocking callback if TRY is set and the lock is not granted.
+ *
+ * LM_FLAG_NOEXP
+ * GFS sets this flag on lock requests it makes while doing journal recovery.
+ * These special requests should not be blocked due to the recovery like
+ * ordinary locks would be.
+ *
+ * LM_FLAG_ANY
+ * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
+ * also be granted in SHARED. The preferred state is whichever is compatible
+ * with other granted locks, or the specified state if no other locks exist.
+ *
+ * LM_FLAG_PRIORITY
+ * Override fairness considerations. Suppose a lock is held in a shared state
+ * and there is a pending request for the deferred state. A shared lock
+ * request with the priority flag would be allowed to bypass the deferred
+ * request and directly join the other shared lock. A shared lock request
+ * without the priority flag might be forced to wait until the deferred
+ * requested had acquired and released the lock.
+ */
+
+#define LM_FLAG_TRY 0x00000001
+#define LM_FLAG_TRY_1CB 0x00000002
+#define LM_FLAG_NOEXP 0x00000004
+#define LM_FLAG_ANY 0x00000008
+#define LM_FLAG_PRIORITY 0x00000010
+
+/*
+ * lm_lock() and lm_async_cb return flags
+ *
+ * LM_OUT_ST_MASK
+ * Masks the lower two bits of lock state in the returned value.
+ *
+ * LM_OUT_CACHEABLE
+ * The lock hasn't been released so GFS can continue to cache data for it.
+ *
+ * LM_OUT_CANCELED
+ * The lock request was canceled.
+ *
+ * LM_OUT_ASYNC
+ * The result of the request will be returned in an LM_CB_ASYNC callback.
+ */
+
+#define LM_OUT_ST_MASK 0x00000003
+#define LM_OUT_CACHEABLE 0x00000004
+#define LM_OUT_CANCELED 0x00000008
+#define LM_OUT_ASYNC 0x00000080
+#define LM_OUT_ERROR 0x00000100
+
+/*
+ * lm_callback_t types
+ *
+ * LM_CB_NEED_E LM_CB_NEED_D LM_CB_NEED_S
+ * Blocking callback, a remote node is requesting the given lock in
+ * EXCLUSIVE, DEFERRED, or SHARED.
+ *
+ * LM_CB_NEED_RECOVERY
+ * The given journal needs to be recovered.
+ *
+ * LM_CB_DROPLOCKS
+ * Reduce the number of cached locks.
+ *
+ * LM_CB_ASYNC
+ * The given lock has been granted.
+ */
+
+#define LM_CB_NEED_E 257
+#define LM_CB_NEED_D 258
+#define LM_CB_NEED_S 259
+#define LM_CB_NEED_RECOVERY 260
+#define LM_CB_DROPLOCKS 261
+#define LM_CB_ASYNC 262
+
+/*
+ * lm_recovery_done() messages
+ */
+
+#define LM_RD_GAVEUP 308
+#define LM_RD_SUCCESS 309
+
+
+struct lm_lockname {
+ uint64_t ln_number;
+ unsigned int ln_type;
+};
+
+#define lm_name_equal(name1, name2) \
+ (((name1)->ln_number == (name2)->ln_number) && \
+ ((name1)->ln_type == (name2)->ln_type)) \
+
+struct lm_async_cb {
+ struct lm_lockname lc_name;
+ int lc_ret;
+};
+
+struct lm_lockstruct;
+
+struct lm_lockops {
+ char lm_proto_name[256];
+
+ /*
+ * Mount/Unmount
+ */
+
+ int (*lm_mount) (char *table_name, char *host_data,
+ lm_callback_t cb, lm_fsdata_t *fsdata,
+ unsigned int min_lvb_size, int flags,
+ struct lm_lockstruct *lockstruct,
+ struct kobject *fskobj);
+
+ void (*lm_others_may_mount) (lm_lockspace_t *lockspace);
+
+ void (*lm_unmount) (lm_lockspace_t *lockspace);
+
+ void (*lm_withdraw) (lm_lockspace_t *lockspace);
+
+ /*
+ * Lock oriented operations
+ */
+
+ int (*lm_get_lock) (lm_lockspace_t *lockspace,
+ struct lm_lockname *name, lm_lock_t **lockp);
+
+ void (*lm_put_lock) (lm_lock_t *lock);
+
+ unsigned int (*lm_lock) (lm_lock_t *lock, unsigned int cur_state,
+ unsigned int req_state, unsigned int flags);
+
+ unsigned int (*lm_unlock) (lm_lock_t *lock, unsigned int cur_state);
+
+ void (*lm_cancel) (lm_lock_t *lock);
+
+ int (*lm_hold_lvb) (lm_lock_t *lock, char **lvbp);
+ void (*lm_unhold_lvb) (lm_lock_t *lock, char *lvb);
+ void (*lm_sync_lvb) (lm_lock_t *lock, char *lvb);
+
+ /*
+ * Posix Lock oriented operations
+ */
+
+ int (*lm_plock_get) (lm_lockspace_t *lockspace,
+ struct lm_lockname *name,
+ struct file *file, struct file_lock *fl);
+
+ int (*lm_plock) (lm_lockspace_t *lockspace,
+ struct lm_lockname *name,
+ struct file *file, int cmd, struct file_lock *fl);
+
+ int (*lm_punlock) (lm_lockspace_t *lockspace,
+ struct lm_lockname *name,
+ struct file *file, struct file_lock *fl);
+
+ /*
+ * Client oriented operations
+ */
+
+ void (*lm_recovery_done) (lm_lockspace_t *lockspace, unsigned int jid,
+ unsigned int message);
+
+ struct module *lm_owner;
+};
+
+/*
+ * lm_mount() return values
+ *
+ * ls_jid - the journal ID this node should use
+ * ls_first - this node is the first to mount the file system
+ * ls_lvb_size - size in bytes of lock value blocks
+ * ls_lockspace - lock module's context for this file system
+ * ls_ops - lock module's functions
+ * ls_flags - lock module features
+ */
+
+struct lm_lockstruct {
+ unsigned int ls_jid;
+ unsigned int ls_first;
+ unsigned int ls_lvb_size;
+ lm_lockspace_t *ls_lockspace;
+ struct lm_lockops *ls_ops;
+ int ls_flags;
+};
+
+void __init gfs2_init_lmh(void);
+
+/*
+ * Lock module bottom interface. A lock module makes itself available to GFS
+ * with these functions.
+ *
+ * For the time being, we copy the gfs1 lock module bottom interface so the
+ * same lock modules can be used with both gfs1 and gfs2 (it won't be possible
+ * to load both gfs1 and gfs2 at once.) Eventually the lock modules will fork
+ * for gfs1/gfs2 and this API can change to the gfs2_ prefix.
+ */
+
+int gfs_register_lockproto(struct lm_lockops *proto);
+
+void gfs_unregister_lockproto(struct lm_lockops *proto);
+
+/*
+ * Lock module top interface. GFS calls these functions when mounting or
+ * unmounting a file system.
+ */
+
+int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,
+ lm_callback_t cb, lm_fsdata_t *fsdata,
+ unsigned int min_lvb_size, int flags,
+ struct lm_lockstruct *lockstruct,
+ struct kobject *fskobj);
+
+void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct);
+
+void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct);
+
+#endif /* __LM_INTERFACE_DOT_H__ */
+
--- /dev/null
+++ b/fs/gfs2/glock.c
@@ -0,0 +1,2492 @@
+/*
+ * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/delay.h>
+#include <linux/sort.h>
+#include <linux/jhash.h>
+#include <linux/kref.h>
+#include <asm/semaphore.h>
+#include <asm/uaccess.h>
+
+#include "gfs2.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"
+
+/* Must be kept in sync with the beginning of struct gfs2_glock */
+struct glock_plug {
+ struct list_head gl_list;
+ unsigned long gl_flags;
+};
+
+struct greedy {
+ struct gfs2_holder gr_gh;
+ struct work_struct gr_work;
+};
+
+typedef void (*glock_examiner) (struct gfs2_glock * gl);
+
+/**
+ * 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(struct lm_lockname *name)
+{
+ unsigned int h;
+
+ h = jhash(&name->ln_number, sizeof(uint64_t), 0);
+ h = jhash(&name->ln_type, sizeof(unsigned int), 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)
+{
+ kref_get(&gl->gl_ref);
+}
+
+/* All work is done after the return from kref_put() so we
+ can release the write_lock before the free. */
+
+static void kill_glock(struct kref *kref)
+{
+ struct gfs2_glock *gl = container_of(kref, struct gfs2_glock, gl_ref);
+ struct gfs2_sbd *sdp = gl->gl_sbd;
+
+ 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_waiters2));
+ gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
+}
+
+/**
+ * gfs2_glock_put() - Decrement reference count on glock
+ * @gl: The glock to put
+ *
+ */
+
+int gfs2_glock_put(struct gfs2_glock *gl)
+{
+ struct gfs2_sbd *sdp = gl->gl_sbd;
+ struct gfs2_gl_hash_bucket *bucket = gl->gl_bucket;
+ int rv = 0;
+
+ mutex_lock(&sdp->sd_invalidate_inodes_mutex);
+
+ write_lock(&bucket->hb_lock);
+ if (kref_put(&gl->gl_ref, kill_glock)) {
+ list_del_init(&gl->gl_list);
+ write_unlock(&bucket->hb_lock);
+ glock_free(gl);
+ rv = 1;
+ goto out;
+ }
+ write_unlock(&bucket->hb_lock);
+ out:
+ mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
+ return rv;
+}
+
+/**
+ * queue_empty - check to see if a glock's queue is empty
+ * @gl: the glock
+ * @head: the head of the queue to check
+ *
+ * This function protects the list in the event that a process already
+ * has a holder on the list and is adding a second holder for itself.
+ * The glmutex lock is what generally prevents processes from working
+ * on the same glock at once, but the special case of adding a second
+ * holder for yourself ("recursive" locking) doesn't involve locking
+ * glmutex, making the spin lock necessary.
+ *
+ * Returns: 1 if the queue is empty
+ */
+
+static inline int queue_empty(struct gfs2_glock *gl, struct list_head *head)
+{
+ int empty;
+ spin_lock(&gl->gl_spin);
+ empty = list_empty(head);
+ spin_unlock(&gl->gl_spin);
+ return empty;
+}
+
+/**
+ * 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(struct gfs2_gl_hash_bucket *bucket,
+ struct lm_lockname *name)
+{
+ struct gfs2_glock *gl;
+
+ list_for_each_entry(gl, &bucket->hb_list, gl_list) {
+ if (test_bit(GLF_PLUG, &gl->gl_flags))
+ continue;
+ if (!lm_name_equal(&gl->gl_name, name))
+ continue;
+
+ kref_get(&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
+ */
+
+struct gfs2_glock *gfs2_glock_find(struct gfs2_sbd *sdp,
+ struct lm_lockname *name)
+{
+ struct gfs2_gl_hash_bucket *bucket = &sdp->sd_gl_hash[gl_hash(name)];
+ struct gfs2_glock *gl;
+
+ read_lock(&bucket->hb_lock);
+ gl = search_bucket(bucket, name);
+ read_unlock(&bucket->hb_lock);
+
+ return 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, uint64_t number,
+ struct gfs2_glock_operations *glops, int create,
+ struct gfs2_glock **glp)
+{
+ struct lm_lockname name;
+ struct gfs2_glock *gl, *tmp;
+ struct gfs2_gl_hash_bucket *bucket;
+ int error;
+
+ name.ln_number = number;
+ name.ln_type = glops->go_type;
+ bucket = &sdp->sd_gl_hash[gl_hash(&name)];
+
+ read_lock(&bucket->hb_lock);
+ gl = search_bucket(bucket, &name);
+ read_unlock(&bucket->hb_lock);
+
+ if (gl || !create) {
+ *glp = gl;
+ return 0;
+ }
+
+ gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
+ if (!gl)
+ return -ENOMEM;
+
+ memset(gl, 0, sizeof(struct gfs2_glock));
+
+ INIT_LIST_HEAD(&gl->gl_list);
+ gl->gl_name = name;
+ kref_init(&gl->gl_ref);
+
+ spin_lock_init(&gl->gl_spin);
+
+ gl->gl_state = LM_ST_UNLOCKED;
+ INIT_LIST_HEAD(&gl->gl_holders);
+ INIT_LIST_HEAD(&gl->gl_waiters1);
+ INIT_LIST_HEAD(&gl->gl_waiters2);
+ INIT_LIST_HEAD(&gl->gl_waiters3);
+
+ gl->gl_ops = glops;
+
+ gl->gl_bucket = bucket;
+ INIT_LIST_HEAD(&gl->gl_reclaim);
+
+ gl->gl_sbd = sdp;
+
+ lops_init_le(&gl->gl_le, &gfs2_glock_lops);
+ INIT_LIST_HEAD(&gl->gl_ail_list);
+
+ /* 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 ||
+ glops == &gfs2_meta_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(&bucket->hb_lock);
+ tmp = search_bucket(bucket, &name);
+ if (tmp) {
+ write_unlock(&bucket->hb_lock);
+ glock_free(gl);
+ gl = tmp;
+ } else {
+ list_add_tail(&gl->gl_list, &bucket->hb_list);
+ write_unlock(&bucket->hb_lock);
+ }
+
+ *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, int flags,
+ struct gfs2_holder *gh)
+{
+ INIT_LIST_HEAD(&gh->gh_list);
+ gh->gh_gl = gl;
+ gh->gh_owner = (flags & GL_NEVER_RECURSE) ? NULL : current;
+ gh->gh_state = state;
+ gh->gh_flags = flags;
+ gh->gh_error = 0;
+ gh->gh_iflags = 0;
+ init_completion(&gh->gh_wait);
+
+ if (gh->gh_state == LM_ST_EXCLUSIVE)
+ gh->gh_flags |= GL_LOCAL_EXCL;
+
+ 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, int flags, struct gfs2_holder *gh)
+{
+ gh->gh_state = state;
+ gh->gh_flags = flags;
+ if (gh->gh_state == LM_ST_EXCLUSIVE)
+ gh->gh_flags |= GL_LOCAL_EXCL;
+
+ gh->gh_iflags &= 1 << HIF_ALLOCED;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * gfs2_holder_get - get a struct gfs2_holder structure
+ * @gl: the glock
+ * @state: the state we're requesting
+ * @flags: the modifier flags
+ * @gfp_flags: __GFP_NOFAIL
+ *
+ * Figure out how big an impact this function has. Either:
+ * 1) Replace it with a cache of structures hanging off the struct gfs2_sbd
+ * 2) Leave it like it is
+ *
+ * Returns: the holder structure, NULL on ENOMEM
+ */
+
+struct gfs2_holder *gfs2_holder_get(struct gfs2_glock *gl, unsigned int state,
+ int flags, gfp_t gfp_flags)
+{
+ struct gfs2_holder *gh;
+
+ gh = kmalloc(sizeof(struct gfs2_holder), gfp_flags);
+ if (!gh)
+ return NULL;
+
+ gfs2_holder_init(gl, state, flags, gh);
+ set_bit(HIF_ALLOCED, &gh->gh_iflags);
+
+ return gh;
+}
+
+/**
+ * gfs2_holder_put - get rid of a struct gfs2_holder structure
+ * @gh: the holder structure
+ *
+ */
+
+void gfs2_holder_put(struct gfs2_holder *gh)
+{
+ gfs2_holder_uninit(gh);
+ kfree(gh);
+}
+
+/**
+ * handle_recurse - put other holder structures (marked recursive)
+ * into the holders list
+ * @gh: the holder structure
+ *
+ */
+
+static void handle_recurse(struct gfs2_holder *gh)
+{
+ struct gfs2_glock *gl = gh->gh_gl;
+ struct gfs2_sbd *sdp = gl->gl_sbd;
+ struct gfs2_holder *tmp_gh, *safe;
+ int found = 0;
+
+ if (gfs2_assert_warn(sdp, gh->gh_owner))
+ return;
+
+ list_for_each_entry_safe(tmp_gh, safe, &gl->gl_waiters3, gh_list) {
+ if (tmp_gh->gh_owner != gh->gh_owner)
+ continue;
+
+ gfs2_assert_warn(sdp,
+ test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
+
+ list_move_tail(&tmp_gh->gh_list, &gl->gl_holders);
+ tmp_gh->gh_error = 0;
+ set_bit(HIF_HOLDER, &tmp_gh->gh_iflags);
+
+ complete(&tmp_gh->gh_wait);
+
+ found = 1;
+ }
+
+ gfs2_assert_warn(sdp, found);
+}
+
+/**
+ * do_unrecurse - a recursive holder was just dropped of the waiters3 list
+ * @gh: the holder
+ *
+ * If there is only one other recursive holder, clear its HIF_RECURSE bit.
+ * If there is more than one, leave them alone.
+ *
+ */
+
+static void do_unrecurse(struct gfs2_holder *gh)
+{
+ struct gfs2_glock *gl = gh->gh_gl;
+ struct gfs2_sbd *sdp = gl->gl_sbd;
+ struct gfs2_holder *tmp_gh, *last_gh = NULL;
+ int found = 0;
+
+ if (gfs2_assert_warn(sdp, gh->gh_owner))
+ return;
+
+ list_for_each_entry(tmp_gh, &gl->gl_waiters3, gh_list) {
+ if (tmp_gh->gh_owner != gh->gh_owner)
+ continue;
+
+ gfs2_assert_warn(sdp,
+ test_bit(HIF_RECURSE, &tmp_gh->gh_iflags));
+
+ if (found)
+ return;
+
+ found = 1;
+ last_gh = tmp_gh;
+ }
+
+ if (!gfs2_assert_warn(sdp, found))
+ clear_bit(HIF_RECURSE, &last_gh->gh_iflags);
+}
+
+/**
+ * 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);
+ complete(&gh->gh_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;
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+ int recurse;
+
+ 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);
+ }
+
+ glops->go_xmote_th(gl, gh->gh_state,
+ gh->gh_flags);
+
+ 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);
+ recurse = 0;
+ } else {
+ struct gfs2_holder *next_gh;
+ if (gh->gh_flags & GL_LOCAL_EXCL)
+ return 1;
+ next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
+ gh_list);
+ if (next_gh->gh_flags & GL_LOCAL_EXCL)
+ return 1;
+ recurse = test_bit(HIF_RECURSE, &gh->gh_iflags);
+ }
+
+ list_move_tail(&gh->gh_list, &gl->gl_holders);
+ gh->gh_error = 0;
+ set_bit(HIF_HOLDER, &gh->gh_iflags);
+
+ if (recurse)
+ handle_recurse(gh);
+
+ complete(&gh->gh_wait);
+
+ 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_holder *gh)
+{
+ struct gfs2_glock *gl = gh->gh_gl;
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+
+ if (!list_empty(&gl->gl_holders))
+ return 1;
+
+ if (gl->gl_state == gh->gh_state || gl->gl_state == LM_ST_UNLOCKED) {
+ list_del_init(&gh->gh_list);
+ gh->gh_error = 0;
+ spin_unlock(&gl->gl_spin);
+ if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
+ gfs2_holder_put(gh);
+ else
+ complete(&gh->gh_wait);
+ spin_lock(&gl->gl_spin);
+ } else {
+ gl->gl_req_gh = gh;
+ set_bit(GLF_LOCK, &gl->gl_flags);
+ spin_unlock(&gl->gl_spin);
+
+ if (gh->gh_state == LM_ST_UNLOCKED ||
+ gl->gl_state != LM_ST_EXCLUSIVE)
+ glops->go_drop_th(gl);
+ else
+ glops->go_xmote_th(gl, gh->gh_state, gh->gh_flags);
+
+ spin_lock(&gl->gl_spin);
+ }
+
+ return 0;
+}
+
+/**
+ * rq_greedy - process a queued request to drop greedy status
+ * @gh: the glock holder
+ *
+ * Returns: 1 if the queue is blocked
+ */
+
+static int rq_greedy(struct gfs2_holder *gh)
+{
+ struct gfs2_glock *gl = gh->gh_gl;
+
+ list_del_init(&gh->gh_list);
+ /* gh->gh_error never examined. */
+ clear_bit(GLF_GREEDY, &gl->gl_flags);
+ spin_unlock(&gl->gl_spin);
+
+ gfs2_holder_uninit(gh);
+ kfree(container_of(gh, struct greedy, gr_gh));
+
+ 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 (!list_empty(&gl->gl_waiters2) &&
+ !test_bit(GLF_SKIP_WAITERS2, &gl->gl_flags)) {
+ gh = list_entry(gl->gl_waiters2.next,
+ struct gfs2_holder, gh_list);
+
+ if (test_bit(HIF_DEMOTE, &gh->gh_iflags))
+ blocked = rq_demote(gh);
+ else if (test_bit(HIF_GREEDY, &gh->gh_iflags))
+ blocked = rq_greedy(gh);
+ else
+ gfs2_assert_warn(gl->gl_sbd, 0);
+
+ } 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.
+ */
+
+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);
+
+ 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
+ complete(&gh.gh_wait);
+ spin_unlock(&gl->gl_spin);
+
+ wait_for_completion(&gh.gh_wait);
+ 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
+ */
+
+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;
+ spin_unlock(&gl->gl_spin);
+
+ return acquired;
+}
+
+/**
+ * gfs2_glmutex_unlock - release a local lock on a glock
+ * @gl: the glock
+ *
+ */
+
+void gfs2_glmutex_unlock(struct gfs2_glock *gl)
+{
+ spin_lock(&gl->gl_spin);
+ clear_bit(GLF_LOCK, &gl->gl_flags);
+ run_queue(gl);
+ spin_unlock(&gl->gl_spin);
+}
+
+/**
+ * handle_callback - add a demote request to a lock's queue
+ * @gl: the glock
+ * @state: the state the caller wants us to change to
+ *
+ */
+
+static void handle_callback(struct gfs2_glock *gl, unsigned int state)
+{
+ struct gfs2_holder *gh, *new_gh = NULL;
+
+ restart:
+ spin_lock(&gl->gl_spin);
+
+ list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
+ if (test_bit(HIF_DEMOTE, &gh->gh_iflags) &&
+ gl->gl_req_gh != gh) {
+ if (gh->gh_state != state)
+ gh->gh_state = LM_ST_UNLOCKED;
+ goto out;
+ }
+ }
+
+ if (new_gh) {
+ list_add_tail(&new_gh->gh_list, &gl->gl_waiters2);
+ new_gh = NULL;
+ } else {
+ spin_unlock(&gl->gl_spin);
+
+ new_gh = gfs2_holder_get(gl, state,
+ LM_FLAG_TRY | GL_NEVER_RECURSE,
+ GFP_KERNEL | __GFP_NOFAIL),
+ set_bit(HIF_DEMOTE, &new_gh->gh_iflags);
+ set_bit(HIF_DEALLOC, &new_gh->gh_iflags);
+
+ goto restart;
+ }
+
+ out:
+ spin_unlock(&gl->gl_spin);
+
+ if (new_gh)
+ gfs2_holder_put(new_gh);
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+ 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, queue_empty(gl, &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 | DIO_DATA);
+ } 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, DIO_DATA);
+ }
+
+ /* Deal with each possible exit condition */
+
+ if (!gh)
+ gl->gl_stamp = jiffies;
+
+ else if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
+ spin_lock(&gl->gl_spin);
+ list_del_init(&gh->gh_list);
+ gh->gh_error = -EIO;
+ if (test_bit(HIF_RECURSE, &gh->gh_iflags))
+ do_unrecurse(gh);
+ spin_unlock(&gl->gl_spin);
+
+ } else if (test_bit(HIF_DEMOTE, &gh->gh_iflags)) {
+ spin_lock(&gl->gl_spin);
+ list_del_init(&gh->gh_list);
+ if (gl->gl_state == gh->gh_state ||
+ gl->gl_state == LM_ST_UNLOCKED)
+ gh->gh_error = 0;
+ else {
+ if (gfs2_assert_warn(sdp, gh->gh_flags &
+ (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) == -1)
+ fs_warn(sdp, "ret = 0x%.8X\n", ret);
+ gh->gh_error = GLR_TRYFAILED;
+ }
+ spin_unlock(&gl->gl_spin);
+
+ if (ret & LM_OUT_CANCELED)
+ handle_callback(gl, LM_ST_UNLOCKED); /* Lame */
+
+ } else if (ret & LM_OUT_CANCELED) {
+ spin_lock(&gl->gl_spin);
+ list_del_init(&gh->gh_list);
+ gh->gh_error = GLR_CANCELED;
+ if (test_bit(HIF_RECURSE, &gh->gh_iflags))
+ do_unrecurse(gh);
+ spin_unlock(&gl->gl_spin);
+
+ } else if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
+ spin_lock(&gl->gl_spin);
+ list_move_tail(&gh->gh_list, &gl->gl_holders);
+ gh->gh_error = 0;
+ set_bit(HIF_HOLDER, &gh->gh_iflags);
+ spin_unlock(&gl->gl_spin);
+
+ set_bit(HIF_FIRST, &gh->gh_iflags);
+
+ op_done = 0;
+
+ } else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
+ spin_lock(&gl->gl_spin);
+ list_del_init(&gh->gh_list);
+ gh->gh_error = GLR_TRYFAILED;
+ if (test_bit(HIF_RECURSE, &gh->gh_iflags))
+ do_unrecurse(gh);
+ spin_unlock(&gl->gl_spin);
+
+ } else {
+ if (gfs2_assert_withdraw(sdp, 0) == -1)
+ fs_err(sdp, "ret = 0x%.8X\n", ret);
+ }
+
+ 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);
+ run_queue(gl);
+ spin_unlock(&gl->gl_spin);
+ }
+
+ gfs2_glock_put(gl);
+
+ if (gh) {
+ if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
+ gfs2_holder_put(gh);
+ else
+ complete(&gh->gh_wait);
+ }
+}
+
+/**
+ * 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
+ *
+ */
+
+void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags)
+{
+ struct gfs2_sbd *sdp = gl->gl_sbd;
+ 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;
+
+ gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
+ gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
+ gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
+ gfs2_assert_warn(sdp, state != gl->gl_state);
+
+ if (gl->gl_state == LM_ST_EXCLUSIVE) {
+ if (glops->go_sync)
+ glops->go_sync(gl,
+ DIO_METADATA | DIO_DATA | DIO_RELEASE);
+ }
+
+ 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;
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+ struct gfs2_holder *gh = gl->gl_req_gh;
+
+ clear_bit(GLF_PREFETCH, &gl->gl_flags);
+
+ gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
+ gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
+ gfs2_assert_warn(sdp, !ret);
+
+ state_change(gl, LM_ST_UNLOCKED);
+
+ if (glops->go_inval)
+ glops->go_inval(gl, DIO_METADATA | DIO_DATA);
+
+ if (gh) {
+ spin_lock(&gl->gl_spin);
+ list_del_init(&gh->gh_list);
+ gh->gh_error = 0;
+ spin_unlock(&gl->gl_spin);
+ }
+
+ if (glops->go_drop_bh)
+ glops->go_drop_bh(gl);
+
+ 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);
+
+ gfs2_glock_put(gl);
+
+ if (gh) {
+ if (test_bit(HIF_DEALLOC, &gh->gh_iflags))
+ gfs2_holder_put(gh);
+ else
+ complete(&gh->gh_wait);
+ }
+}
+
+/**
+ * gfs2_glock_drop_th - call into the lock module to unlock a lock
+ * @gl: the glock
+ *
+ */
+
+void gfs2_glock_drop_th(struct gfs2_glock *gl)
+{
+ struct gfs2_sbd *sdp = gl->gl_sbd;
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+ unsigned int ret;
+
+ gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
+ gfs2_assert_warn(sdp, queue_empty(gl, &gl->gl_holders));
+ gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
+
+ if (gl->gl_state == LM_ST_EXCLUSIVE) {
+ if (glops->go_sync)
+ glops->go_sync(gl,
+ DIO_METADATA | DIO_DATA | DIO_RELEASE);
+ }
+
+ 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;
+ 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;
+ if (test_bit(HIF_RECURSE, &gh->gh_iflags))
+ do_unrecurse(gh);
+ 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_for_completion(&gh->gh_wait);
+
+ 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);
+ if (test_and_clear_bit(HIF_RECURSE,
+ &gh->gh_iflags))
+ do_unrecurse(gh);
+ 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);
+ if (test_bit(HIF_RECURSE, &gh->gh_iflags))
+ handle_recurse(gh);
+ 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, struct task_struct *owner)
+{
+ struct gfs2_holder *gh;
+
+ list_for_each_entry(gh, head, gh_list) {
+ if (gh->gh_owner == owner)
+ return gh;
+ }
+
+ return NULL;
+}
+
+/**
+ * recurse_check -
+ *
+ * Make sure the new holder is compatible with the pre-existing one.
+ *
+ */
+
+static int recurse_check(struct gfs2_holder *existing, struct gfs2_holder *new,
+ unsigned int state)
+{
+ struct gfs2_sbd *sdp = existing->gh_gl->gl_sbd;
+
+ if (gfs2_assert_warn(sdp, (new->gh_flags & LM_FLAG_ANY) ||
+ !(existing->gh_flags & LM_FLAG_ANY)))
+ goto fail;
+
+ if (gfs2_assert_warn(sdp, (existing->gh_flags & GL_LOCAL_EXCL) ||
+ !(new->gh_flags & GL_LOCAL_EXCL)))
+ goto fail;
+
+ if (gfs2_assert_warn(sdp, relaxed_state_ok(state, new->gh_state,
+ new->gh_flags)))
+ goto fail;
+
+ return 0;
+
+ fail:
+ set_bit(HIF_ABORTED, &new->gh_iflags);
+ return -EINVAL;
+}
+
+/**
+ * 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;
+
+ if (!gh->gh_owner)
+ goto out;
+
+ existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
+ if (existing) {
+ if (recurse_check(existing, gh, gl->gl_state))
+ return;
+
+ list_add_tail(&gh->gh_list, &gl->gl_holders);
+ set_bit(HIF_HOLDER, &gh->gh_iflags);
+
+ gh->gh_error = 0;
+ complete(&gh->gh_wait);
+
+ return;
+ }
+
+ existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
+ if (existing) {
+ if (recurse_check(existing, gh, existing->gh_state))
+ return;
+
+ set_bit(HIF_RECURSE, &gh->gh_iflags);
+ set_bit(HIF_RECURSE, &existing->gh_iflags);
+
+ list_add_tail(&gh->gh_list, &gl->gl_waiters3);
+
+ return;
+ }
+
+ out:
+ 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(1000);
+ goto restart;
+ }
+ }
+
+ clear_bit(GLF_PREFETCH, &gl->gl_flags);
+
+ 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(1000);
+ 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(1000);
+ 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;
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+
+ if (gh->gh_flags & GL_SYNC)
+ set_bit(GLF_SYNC, &gl->gl_flags);
+
+ if (gh->gh_flags & GL_NOCACHE)
+ handle_callback(gl, LM_ST_UNLOCKED);
+
+ 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);
+
+ if (test_bit(GLF_SYNC, &gl->gl_flags)) {
+ if (glops->go_sync)
+ glops->go_sync(gl, DIO_METADATA | DIO_DATA);
+ }
+
+ gl->gl_stamp = jiffies;
+
+ spin_lock(&gl->gl_spin);
+ }
+
+ clear_bit(GLF_LOCK, &gl->gl_flags);
+ run_queue(gl);
+ spin_unlock(&gl->gl_spin);
+}
+
+/**
+ * gfs2_glock_prefetch - Try to prefetch a glock
+ * @gl: the glock
+ * @state: the state to prefetch in
+ * @flags: flags passed to go_xmote_th()
+ *
+ */
+
+void gfs2_glock_prefetch(struct gfs2_glock *gl, unsigned int state, int flags)
+{
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+
+ spin_lock(&gl->gl_spin);
+
+ if (test_bit(GLF_LOCK, &gl->gl_flags) ||
+ !list_empty(&gl->gl_holders) ||
+ !list_empty(&gl->gl_waiters1) ||
+ !list_empty(&gl->gl_waiters2) ||
+ !list_empty(&gl->gl_waiters3) ||
+ relaxed_state_ok(gl->gl_state, state, flags)) {
+ spin_unlock(&gl->gl_spin);
+ return;
+ }
+
+ set_bit(GLF_PREFETCH, &gl->gl_flags);
+ set_bit(GLF_LOCK, &gl->gl_flags);
+ spin_unlock(&gl->gl_spin);
+
+ glops->go_xmote_th(gl, state, flags);
+}
+
+/**
+ * gfs2_glock_force_drop - Force a glock to be uncached
+ * @gl: the glock
+ *
+ */
+
+void gfs2_glock_force_drop(struct gfs2_glock *gl)
+{
+ struct gfs2_holder gh;
+
+ gfs2_holder_init(gl, LM_ST_UNLOCKED, GL_NEVER_RECURSE, &gh);
+ set_bit(HIF_DEMOTE, &gh.gh_iflags);
+
+ spin_lock(&gl->gl_spin);
+ list_add_tail(&gh.gh_list, &gl->gl_waiters2);
+ run_queue(gl);
+ spin_unlock(&gl->gl_spin);
+
+ wait_for_completion(&gh.gh_wait);
+ gfs2_holder_uninit(&gh);
+}
+
+static void greedy_work(void *data)
+{
+ struct greedy *gr = (struct greedy *)data;
+ struct gfs2_holder *gh = &gr->gr_gh;
+ struct gfs2_glock *gl = gh->gh_gl;
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+
+ clear_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
+
+ if (glops->go_greedy)
+ glops->go_greedy(gl);
+
+ spin_lock(&gl->gl_spin);
+
+ if (list_empty(&gl->gl_waiters2)) {
+ clear_bit(GLF_GREEDY, &gl->gl_flags);
+ spin_unlock(&gl->gl_spin);
+ gfs2_holder_uninit(gh);
+ kfree(gr);
+ } else {
+ gfs2_glock_hold(gl);
+ list_add_tail(&gh->gh_list, &gl->gl_waiters2);
+ run_queue(gl);
+ spin_unlock(&gl->gl_spin);
+ gfs2_glock_put(gl);
+ }
+}
+
+/**
+ * gfs2_glock_be_greedy -
+ * @gl:
+ * @time:
+ *
+ * Returns: 0 if go_greedy will be called, 1 otherwise
+ */
+
+int gfs2_glock_be_greedy(struct gfs2_glock *gl, unsigned int time)
+{
+ struct greedy *gr;
+ struct gfs2_holder *gh;
+
+ if (!time ||
+ gl->gl_sbd->sd_args.ar_localcaching ||
+ test_and_set_bit(GLF_GREEDY, &gl->gl_flags))
+ return 1;
+
+ gr = kmalloc(sizeof(struct greedy), GFP_KERNEL);
+ if (!gr) {
+ clear_bit(GLF_GREEDY, &gl->gl_flags);
+ return 1;
+ }
+ gh = &gr->gr_gh;
+
+ gfs2_holder_init(gl, 0, GL_NEVER_RECURSE, gh);
+ set_bit(HIF_GREEDY, &gh->gh_iflags);
+ INIT_WORK(&gr->gr_work, greedy_work, gr);
+
+ set_bit(GLF_SKIP_WAITERS2, &gl->gl_flags);
+ schedule_delayed_work(&gr->gr_work, time);
+
+ return 0;
+}
+
+/**
+ * gfs2_glock_nq_init - intialize a holder and enqueue it on a glock
+ * @gl: the glock
+ * @state: the state we're requesting
+ * @flags: the modifier flags
+ * @gh: the holder structure
+ *
+ * Returns: 0, GLR_*, or errno
+ */
+
+int gfs2_glock_nq_init(struct gfs2_glock *gl, unsigned int state, int flags,
+ struct gfs2_holder *gh)
+{
+ int error;
+
+ gfs2_holder_init(gl, state, flags, gh);
+
+ error = gfs2_glock_nq(gh);
+ if (error)
+ gfs2_holder_uninit(gh);
+
+ return error;
+}
+
+/**
+ * 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, uint64_t number,
+ 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)
+{
+ struct gfs2_holder *gh_a = *(struct gfs2_holder **)arg_a;
+ struct gfs2_holder *gh_b = *(struct gfs2_holder **)arg_b;
+ struct lm_lockname *a = &gh_a->gh_gl->gl_name;
+ struct lm_lockname *b = &gh_b->gh_gl->gl_name;
+ int ret = 0;
+
+ if (a->ln_number > b->ln_number)
+ ret = 1;
+ else if (a->ln_number < b->ln_number)
+ ret = -1;
+ else {
+ if (gh_a->gh_state == LM_ST_SHARED &&
+ gh_b->gh_state == LM_ST_EXCLUSIVE)
+ ret = 1;
+ else if (!(gh_a->gh_flags & GL_LOCAL_EXCL) &&
+ (gh_b->gh_flags & GL_LOCAL_EXCL))
+ ret = 1;
+ }
+
+ return ret;
+}
+
+/**
+ * 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
+ *
+ * Figure out how big an impact this function has. Either:
+ * 1) Replace this code with code that calls gfs2_glock_prefetch()
+ * 2) Forget async stuff and just call nq_m_sync()
+ * 3) Leave it like it is
+ *
+ * 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)
+{
+ int *e;
+ unsigned int x;
+ int borked = 0, serious = 0;
+ int error = 0;
+
+ if (!num_gh)
+ return 0;
+
+ if (num_gh == 1) {
+ ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
+ return gfs2_glock_nq(ghs);
+ }
+
+ e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
+ if (!e)
+ return -ENOMEM;
+
+ for (x = 0; x < num_gh; x++) {
+ ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
+ error = gfs2_glock_nq(&ghs[x]);
+ if (error) {
+ borked = 1;
+ serious = error;
+ num_gh = x;
+ break;
+ }
+ }
+
+ for (x = 0; x < num_gh; x++) {
+ error = e[x] = glock_wait_internal(&ghs[x]);
+ if (error) {
+ borked = 1;
+ if (error != GLR_TRYFAILED && error != GLR_CANCELED)
+ serious = error;
+ }
+ }
+
+ if (!borked) {
+ kfree(e);
+ return 0;
+ }
+
+ for (x = 0; x < num_gh; x++)
+ if (!e[x])
+ gfs2_glock_dq(&ghs[x]);
+
+ if (serious)
+ error = serious;
+ else {
+ for (x = 0; x < num_gh; x++)
+ gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
+ &ghs[x]);
+ error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
+ }
+
+ kfree(e);
+
+ 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_glock_prefetch_num - prefetch 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
+ *
+ * Returns: errno
+ */
+
+void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, uint64_t number,
+ struct gfs2_glock_operations *glops,
+ unsigned int state, int flags)
+{
+ struct gfs2_glock *gl;
+ int error;
+
+ if (atomic_read(&sdp->sd_reclaim_count) <
+ gfs2_tune_get(sdp, gt_reclaim_limit)) {
+ error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
+ if (!error) {
+ gfs2_glock_prefetch(gl, state, flags);
+ gfs2_glock_put(gl);
+ }
+ }
+}
+
+/**
+ * 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);
+}
+
+void gfs2_lvb_sync(struct gfs2_glock *gl)
+{
+ gfs2_glmutex_lock(gl);
+
+ gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count));
+ if (!gfs2_assert_warn(gl->gl_sbd, gfs2_glock_is_held_excl(gl)))
+ gfs2_lm_sync_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
+
+ gfs2_glmutex_unlock(gl);
+}
+
+static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
+ unsigned int state)
+{
+ struct gfs2_glock *gl;
+
+ gl = gfs2_glock_find(sdp, name);
+ if (!gl)
+ return;
+
+ if (gl->gl_ops->go_callback)
+ gl->gl_ops->go_callback(gl, state);
+ handle_callback(gl, state);
+
+ spin_lock(&gl->gl_spin);
+ run_queue(gl);
+ spin_unlock(&gl->gl_spin);
+
+ gfs2_glock_put(gl);
+}
+
+/**
+ * gfs2_glock_cb - Callback used by locking module
+ * @fsdata: 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(lm_fsdata_t *fsdata, unsigned int type, void *data)
+{
+ struct gfs2_sbd *sdp = (struct gfs2_sbd *)fsdata;
+
+ switch (type) {
+ case LM_CB_NEED_E:
+ blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_UNLOCKED);
+ return;
+
+ case LM_CB_NEED_D:
+ blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_DEFERRED);
+ return;
+
+ case LM_CB_NEED_S:
+ blocking_cb(sdp, (struct lm_lockname *)data, LM_ST_SHARED);
+ return;
+
+ case LM_CB_ASYNC: {
+ struct lm_async_cb *async = (struct lm_async_cb *)data;
+ struct gfs2_glock *gl;
+
+ 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);
+ gfs2_glock_put(gl);
+
+ 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;
+ }
+}
+
+/**
+ * gfs2_try_toss_inode - try to remove a particular inode struct from cache
+ * sdp: the filesystem
+ * inum: the inode number
+ *
+ */
+
+void gfs2_try_toss_inode(struct gfs2_sbd *sdp, struct gfs2_inum *inum)
+{
+ struct gfs2_glock *gl;
+ struct gfs2_inode *ip;
+ int error;
+
+ error = gfs2_glock_get(sdp, inum->no_addr, &gfs2_inode_glops,
+ NO_CREATE, &gl);
+ if (error || !gl)
+ return;
+
+ if (!gfs2_glmutex_trylock(gl))
+ goto out;
+
+ ip = get_gl2ip(gl);
+ if (!ip)
+ goto out_unlock;
+
+ if (atomic_read(&ip->i_count))
+ goto out_unlock;
+
+ gfs2_inode_destroy(ip);
+
+ out_unlock:
+ gfs2_glmutex_unlock(gl);
+
+ out:
+ gfs2_glock_put(gl);
+}
+
+/**
+ * gfs2_iopen_go_callback - Try to kick the inode/vnode associated with an
+ * iopen glock from memory
+ * @io_gl: the iopen glock
+ * @state: the state into which the glock should be put
+ *
+ */
+
+void gfs2_iopen_go_callback(struct gfs2_glock *io_gl, unsigned int state)
+{
+ struct gfs2_glock *i_gl;
+
+ if (state != LM_ST_UNLOCKED)
+ return;
+
+ spin_lock(&io_gl->gl_spin);
+ i_gl = get_gl2gl(io_gl);
+ if (i_gl) {
+ gfs2_glock_hold(i_gl);
+ spin_unlock(&io_gl->gl_spin);
+ } else {
+ spin_unlock(&io_gl->gl_spin);
+ return;
+ }
+
+ if (gfs2_glmutex_trylock(i_gl)) {
+ struct gfs2_inode *ip = get_gl2ip(i_gl);
+ if (ip) {
+ gfs2_try_toss_vnode(ip);
+ gfs2_glmutex_unlock(i_gl);
+ gfs2_glock_schedule_for_reclaim(i_gl);
+ goto out;
+ }
+ gfs2_glmutex_unlock(i_gl);
+ }
+
+ out:
+ gfs2_glock_put(i_gl);
+}
+
+/**
+ * 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)
+{
+ struct gfs2_sbd *sdp = gl->gl_sbd;
+ struct gfs2_glock_operations *glops = gl->gl_ops;
+ int demote = 1;
+
+ if (test_bit(GLF_STICKY, &gl->gl_flags))
+ demote = 0;
+ else if (test_bit(GLF_PREFETCH, &gl->gl_flags))
+ demote = time_after_eq(jiffies,
+ gl->gl_stamp +
+ gfs2_tune_get(sdp, gt_prefetch_secs) * HZ);
+ 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 (gl->gl_ops == &gfs2_inode_glops) {
+ struct gfs2_inode *ip = get_gl2ip(gl);
+ if (ip && !atomic_read(&ip->i_count))
+ gfs2_inode_destroy(ip);
+ }
+ if (queue_empty(gl, &gl->gl_holders) &&
+ gl->gl_state != LM_ST_UNLOCKED &&
+ demote_ok(gl))
+ handle_callback(gl, LM_ST_UNLOCKED);
+ 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,
+ struct gfs2_gl_hash_bucket *bucket)
+{
+ struct glock_plug plug;
+ struct list_head *tmp;
+ struct gfs2_glock *gl;
+ int entries;
+
+ /* Add "plug" to end of bucket list, work back up list from there */
+ memset(&plug.gl_flags, 0, sizeof(unsigned long));
+ set_bit(GLF_PLUG, &plug.gl_flags);
+
+ write_lock(&bucket->hb_lock);
+ list_add(&plug.gl_list, &bucket->hb_list);
+ write_unlock(&bucket->hb_lock);
+
+ for (;;) {
+ write_lock(&bucket->hb_lock);
+
+ for (;;) {
+ tmp = plug.gl_list.next;
+
+ if (tmp == &bucket->hb_list) {
+ list_del(&plug.gl_list);
+ entries = !list_empty(&bucket->hb_list);
+ write_unlock(&bucket->hb_lock);
+ return entries;
+ }
+ gl = list_entry(tmp, struct gfs2_glock, gl_list);
+
+ /* Move plug up list */
+ list_move(&plug.gl_list, &gl->gl_list);
+
+ if (test_bit(GLF_PLUG, &gl->gl_flags))
+ continue;
+
+ /* examiner() must glock_put() */
+ gfs2_glock_hold(gl);
+
+ break;
+ }
+
+ write_unlock(&bucket->hb_lock);
+
+ examiner(gl);
+ }
+}
+
+/**
+ * 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 (gfs2_glmutex_trylock(gl)) {
+ if (gl->gl_ops == &gfs2_inode_glops) {
+ struct gfs2_inode *ip = get_gl2ip(gl);
+ if (ip && !atomic_read(&ip->i_count))
+ goto out_schedule;
+ }
+ if (queue_empty(gl, &gl->gl_holders) &&
+ gl->gl_state != LM_ST_UNLOCKED &&
+ demote_ok(gl))
+ goto out_schedule;
+
+ gfs2_glmutex_unlock(gl);
+ }
+
+ gfs2_glock_put(gl);
+
+ return;
+
+ out_schedule:
+ gfs2_glmutex_unlock(gl);
+ gfs2_glock_schedule_for_reclaim(gl);
+ gfs2_glock_put(gl);
+}
+
+/**
+ * gfs2_scand_internal - Look for glocks and inodes to toss from memory
+ * @sdp: the filesystem
+ *
+ */
+
+void gfs2_scand_internal(struct gfs2_sbd *sdp)
+{
+ unsigned int x;
+
+ for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
+ examine_bucket(scan_glock, sdp, &sdp->sd_gl_hash[x]);
+ cond_resched();
+ }
+}
+
+/**
+ * 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);
+ released = gfs2_glock_put(gl);
+ gfs2_assert(sdp, !released);
+ }
+ spin_unlock(&sdp->sd_reclaim_lock);
+
+ if (gfs2_glmutex_trylock(gl)) {
+ if (gl->gl_ops == &gfs2_inode_glops) {
+ struct gfs2_inode *ip = get_gl2ip(gl);
+ if (ip && !atomic_read(&ip->i_count))
+ gfs2_inode_destroy(ip);
+ }
+ if (queue_empty(gl, &gl->gl_holders) &&
+ gl->gl_state != LM_ST_UNLOCKED)
+ handle_callback(gl, LM_ST_UNLOCKED);
+
+ gfs2_glmutex_unlock(gl);
+ }
+
+ gfs2_glock_put(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,
+ &sdp->sd_gl_hash[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;
+ }
+
+ /* invalidate_inodes() requires that the sb inodes list
+ not change, but an async completion callback for an
+ unlock can occur which does glock_put() which
+ can call iput() which will change the sb inodes list.
+ invalidate_inodes_mutex prevents glock_put()'s during
+ an invalidate_inodes() */
+
+ mutex_lock(&sdp->sd_invalidate_inodes_mutex);
+ invalidate_inodes(sdp->sd_vfs);
+ mutex_unlock(&sdp->sd_invalidate_inodes_mutex);
+ yield();
+ }
+}
+
+/*
+ * Diagnostic routines to help debug distributed deadlock
+ */
+
+/**
+ * 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(char *str, struct gfs2_holder *gh)
+{
+ unsigned int x;
+ int error = -ENOBUFS;
+
+ printk(" %s\n", str);
+ printk(" owner = %ld\n",
+ (gh->gh_owner) ? (long)gh->gh_owner->pid : -1);
+ printk(" gh_state = %u\n", gh->gh_state);
+ printk(" gh_flags =");
+ for (x = 0; x < 32; x++)
+ if (gh->gh_flags & (1 << x))
+ printk(" %u", x);
+ printk(" \n");
+ printk(" error = %d\n", gh->gh_error);
+ printk(" gh_iflags =");
+ for (x = 0; x < 32; x++)
+ if (test_bit(x, &gh->gh_iflags))
+ printk(" %u", x);
+ printk(" \n");
+
+ error = 0;
+
+ return error;
+}
+
+/**
+ * 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 gfs2_inode *ip)
+{
+ unsigned int x;
+ int error = -ENOBUFS;
+
+ printk(" Inode:\n");
+ printk(" num = %llu %llu\n",
+ ip->i_num.no_formal_ino, ip->i_num.no_addr);
+ printk(" type = %u\n", IF2DT(ip->i_di.di_mode));
+ printk(" i_count = %d\n", atomic_read(&ip->i_count));
+ printk(" i_flags =");
+ for (x = 0; x < 32; x++)
+ if (test_bit(x, &ip->i_flags))
+ printk(" %u", x);
+ printk(" \n");
+ printk(" vnode = %s\n", (ip->i_vnode) ? "yes" : "no");
+
+ error = 0;
+
+ return error;
+}
+
+/**
+ * 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 gfs2_glock *gl)
+{
+ struct gfs2_holder *gh;
+ unsigned int x;
+ int error = -ENOBUFS;
+
+ spin_lock(&gl->gl_spin);
+
+ printk("Glock (%u, %llu)\n",
+ gl->gl_name.ln_type,
+ gl->gl_name.ln_number);
+ printk(" gl_flags =");
+ for (x = 0; x < 32; x++)
+ if (test_bit(x, &gl->gl_flags))
+ printk(" %u", x);
+ printk(" \n");
+ printk(" gl_ref = %d\n", atomic_read(&gl->gl_ref.refcount));
+ printk(" gl_state = %u\n", gl->gl_state);
+ printk(" req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
+ printk(" req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
+ printk(" lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
+ printk(" object = %s\n", (gl->gl_object) ? "yes" : "no");
+ printk(" le = %s\n",
+ (list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
+ printk(" reclaim = %s\n",
+ (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
+ if (gl->gl_aspace)
+ printk(" aspace = %lu\n",
+ gl->gl_aspace->i_mapping->nrpages);
+ else
+ printk(" aspace = no\n");
+ printk(" ail = %d\n", atomic_read(&gl->gl_ail_count));
+ if (gl->gl_req_gh) {
+ error = dump_holder("Request", gl->gl_req_gh);
+ if (error)
+ goto out;
+ }
+ list_for_each_entry(gh, &gl->gl_holders, gh_list) {
+ error = dump_holder("Holder", gh);
+ if (error)
+ goto out;
+ }
+ list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
+ error = dump_holder("Waiter1", gh);
+ if (error)
+ goto out;
+ }
+ list_for_each_entry(gh, &gl->gl_waiters2, gh_list) {
+ error = dump_holder("Waiter2", gh);
+ if (error)
+ goto out;
+ }
+ list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
+ error = dump_holder("Waiter3", gh);
+ if (error)
+ goto out;
+ }
+ if (gl->gl_ops == &gfs2_inode_glops && get_gl2ip(gl)) {
+ if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
+ list_empty(&gl->gl_holders)) {
+ error = dump_inode(get_gl2ip(gl));
+ if (error)
+ goto out;
+ } else {
+ error = -ENOBUFS;
+ printk(" 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.
+ *
+ */
+
+int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
+{
+ struct gfs2_gl_hash_bucket *bucket;
+ struct gfs2_glock *gl;
+ unsigned int x;
+ int error = 0;
+
+ for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
+ bucket = &sdp->sd_gl_hash[x];
+
+ read_lock(&bucket->hb_lock);
+
+ list_for_each_entry(gl, &bucket->hb_list, gl_list) {
+ if (test_bit(GLF_PLUG, &gl->gl_flags))
+ continue;
+
+ error = dump_glock(gl);
+ if (error)
+ break;
+ }
+
+ read_unlock(&bucket->hb_lock);
+
+ if (error)
+ break;
+ }
+
+
+ return error;
+}
+
--- /dev/null
+++ b/fs/gfs2/glock.h
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.2.
+ */
+
+#ifndef __GLOCK_DOT_H__
+#define __GLOCK_DOT_H__
+
+/* Flags for lock requests; used in gfs2_holder gh_flag field.
+ From lm_interface.h:
+#define LM_FLAG_TRY 0x00000001
+#define LM_FLAG_TRY_1CB 0x00000002
+#define LM_FLAG_NOEXP 0x00000004
+#define LM_FLAG_ANY 0x00000008
+#define LM_FLAG_PRIORITY 0x00000010 */
+
+#define GL_LOCAL_EXCL 0x00000020
+#define GL_ASYNC 0x00000040
+#define GL_EXACT 0x00000080
+#define GL_SKIP 0x00000100
+#define GL_ATIME 0x00000200
+#define GL_NOCACHE 0x00000400
+#define GL_SYNC 0x00000800
+#define GL_NOCANCEL 0x00001000
+#define GL_NEVER_RECURSE 0x00002000
+
+#define GLR_TRYFAILED 13
+#define GLR_CANCELED 14
+
+static inline int gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
+{
+ struct gfs2_holder *gh;
+ int locked = 0;
+
+ /* Look in glock's list of holders for one with current task as owner */
+ spin_lock(&gl->gl_spin);
+ list_for_each_entry(gh, &gl->gl_holders, gh_list) {
+ if (gh->gh_owner == current) {
+ locked = 1;
+ break;
+ }
+ }
+ spin_unlock(&gl->gl_spin);
+
+ return locked;
+}
+
+static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
+{
+ return (gl->gl_state == LM_ST_EXCLUSIVE);
+}
+
+static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
+{
+ return (gl->gl_state == LM_ST_DEFERRED);
+}
+
+static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
+{
+ return (gl->gl_state == LM_ST_SHARED);
+}
+
+static inline int gfs2_glock_is_blocking(struct gfs2_glock *gl)
+{
+ int ret;
+ spin_lock(&gl->gl_spin);
+ ret = !list_empty(&gl->gl_waiters2) || !list_empty(&gl->gl_waiters3);
+ spin_unlock(&gl->gl_spin);
+ return ret;
+}
+
+struct gfs2_glock *gfs2_glock_find(struct gfs2_sbd *sdp,
+ struct lm_lockname *name);
+int gfs2_glock_get(struct gfs2_sbd *sdp,
+ uint64_t number, struct gfs2_glock_operations *glops,
+ int create, struct gfs2_glock **glp);
+void gfs2_glock_hold(struct gfs2_glock *gl);
+int gfs2_glock_put(struct gfs2_glock *gl);
+
+void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, int flags,
+ struct gfs2_holder *gh);
+void gfs2_holder_reinit(unsigned int state, int flags, struct gfs2_holder *gh);
+void gfs2_holder_uninit(struct gfs2_holder *gh);
+struct gfs2_holder *gfs2_holder_get(struct gfs2_glock *gl, unsigned int state,
+ int flags, gfp_t gfp_flags);
+void gfs2_holder_put(struct gfs2_holder *gh);
+
+void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags);
+void gfs2_glock_drop_th(struct gfs2_glock *gl);
+
+void gfs2_glmutex_lock(struct gfs2_glock *gl);
+int gfs2_glmutex_trylock(struct gfs2_glock *gl);
+void gfs2_glmutex_unlock(struct gfs2_glock *gl);
+
+int gfs2_glock_nq(struct gfs2_holder *gh);
+int gfs2_glock_poll(struct gfs2_holder *gh);
+int gfs2_glock_wait(struct gfs2_holder *gh);
+void gfs2_glock_dq(struct gfs2_holder *gh);
+
+void gfs2_glock_prefetch(struct gfs2_glock *gl, unsigned int state, int flags);
+void gfs2_glock_force_drop(struct gfs2_glock *gl);
+
+int gfs2_glock_be_greedy(struct gfs2_glock *gl, unsigned int time);
+
+int gfs2_glock_nq_init(struct gfs2_glock *gl, unsigned int state, int flags,
+ struct gfs2_holder *gh);
+void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
+int gfs2_glock_nq_num(struct gfs2_sbd *sdp,
+ uint64_t number, struct gfs2_glock_operations *glops,
+ unsigned int state, int flags, struct gfs2_holder *gh);
+
+int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
+void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
+void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs);
+
+void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, uint64_t number,
+ struct gfs2_glock_operations *glops,
+ unsigned int state, int flags);
+
+/* Lock Value Block functions */
+
+int gfs2_lvb_hold(struct gfs2_glock *gl);
+void gfs2_lvb_unhold(struct gfs2_glock *gl);
+void gfs2_lvb_sync(struct gfs2_glock *gl);
+
+void gfs2_glock_cb(lm_fsdata_t *fsdata, unsigned int type, void *data);
+
+void gfs2_try_toss_inode(struct gfs2_sbd *sdp, struct gfs2_inum *inum);
+void gfs2_iopen_go_callback(struct gfs2_glock *gl, unsigned int state);
+
+void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl);
+void gfs2_reclaim_glock(struct gfs2_sbd *sdp);
+
+void gfs2_scand_internal(struct gfs2_sbd *sdp);
+void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait);
+
+int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
+
+#endif /* __GLOCK_DOT_H__ */

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