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aha/fs/ocfs2/dlmglue.c
Joel Becker 0fcaa56a2a ocfs2: Simplify ocfs2_read_block() 
More than 30 callers of ocfs2_read_block() pass exactly OCFS2_BH_CACHED.
Only six pass a different flag set.  Rather than have every caller care,
let's make ocfs2_read_block() take no flags and always do a cached read.
The remaining six places can call ocfs2_read_blocks() directly.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-10-14 11:51:57 -07:00

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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* dlmglue.c
*
* Code which implements an OCFS2 specific interface to our DLM.
*
* Copyright (C) 2003, 2004 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/kthread.h>
#include <linux/pagemap.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/time.h>
#define MLOG_MASK_PREFIX ML_DLM_GLUE
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "ocfs2_lockingver.h"
#include "alloc.h"
#include "dcache.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "file.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "stackglue.h"
#include "slot_map.h"
#include "super.h"
#include "uptodate.h"
#include "buffer_head_io.h"
struct ocfs2_mask_waiter {
struct list_head mw_item;
int mw_status;
struct completion mw_complete;
unsigned long mw_mask;
unsigned long mw_goal;
#ifdef CONFIG_OCFS2_FS_STATS
unsigned long long mw_lock_start;
#endif
};
static struct ocfs2_super *ocfs2_get_dentry_osb(struct ocfs2_lock_res *lockres);
static struct ocfs2_super *ocfs2_get_inode_osb(struct ocfs2_lock_res *lockres);
static struct ocfs2_super *ocfs2_get_file_osb(struct ocfs2_lock_res *lockres);
/*
* Return value from ->downconvert_worker functions.
*
* These control the precise actions of ocfs2_unblock_lock()
* and ocfs2_process_blocked_lock()
*
*/
enum ocfs2_unblock_action {
UNBLOCK_CONTINUE = 0, /* Continue downconvert */
UNBLOCK_CONTINUE_POST = 1, /* Continue downconvert, fire
* ->post_unlock callback */
UNBLOCK_STOP_POST = 2, /* Do not downconvert, fire
* ->post_unlock() callback. */
};
struct ocfs2_unblock_ctl {
int requeue;
enum ocfs2_unblock_action unblock_action;
};
static int ocfs2_check_meta_downconvert(struct ocfs2_lock_res *lockres,
int new_level);
static void ocfs2_set_meta_lvb(struct ocfs2_lock_res *lockres);
static int ocfs2_data_convert_worker(struct ocfs2_lock_res *lockres,
int blocking);
static int ocfs2_dentry_convert_worker(struct ocfs2_lock_res *lockres,
int blocking);
static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres);
#define mlog_meta_lvb(__level, __lockres) ocfs2_dump_meta_lvb_info(__level, __PRETTY_FUNCTION__, __LINE__, __lockres)
/* This aids in debugging situations where a bad LVB might be involved. */
static void ocfs2_dump_meta_lvb_info(u64 level,
const char *function,
unsigned int line,
struct ocfs2_lock_res *lockres)
{
struct ocfs2_meta_lvb *lvb =
(struct ocfs2_meta_lvb *)ocfs2_dlm_lvb(&lockres->l_lksb);
mlog(level, "LVB information for %s (called from %s:%u):\n",
lockres->l_name, function, line);
mlog(level, "version: %u, clusters: %u, generation: 0x%x\n",
lvb->lvb_version, be32_to_cpu(lvb->lvb_iclusters),
be32_to_cpu(lvb->lvb_igeneration));
mlog(level, "size: %llu, uid %u, gid %u, mode 0x%x\n",
(unsigned long long)be64_to_cpu(lvb->lvb_isize),
be32_to_cpu(lvb->lvb_iuid), be32_to_cpu(lvb->lvb_igid),
be16_to_cpu(lvb->lvb_imode));
mlog(level, "nlink %u, atime_packed 0x%llx, ctime_packed 0x%llx, "
"mtime_packed 0x%llx iattr 0x%x\n", be16_to_cpu(lvb->lvb_inlink),
(long long)be64_to_cpu(lvb->lvb_iatime_packed),
(long long)be64_to_cpu(lvb->lvb_ictime_packed),
(long long)be64_to_cpu(lvb->lvb_imtime_packed),
be32_to_cpu(lvb->lvb_iattr));
}
/*
* OCFS2 Lock Resource Operations
*
* These fine tune the behavior of the generic dlmglue locking infrastructure.
*
* The most basic of lock types can point ->l_priv to their respective
* struct ocfs2_super and allow the default actions to manage things.
*
* Right now, each lock type also needs to implement an init function,
* and trivial lock/unlock wrappers. ocfs2_simple_drop_lockres()
* should be called when the lock is no longer needed (i.e., object
* destruction time).
*/
struct ocfs2_lock_res_ops {
/*
* Translate an ocfs2_lock_res * into an ocfs2_super *. Define
* this callback if ->l_priv is not an ocfs2_super pointer
*/
struct ocfs2_super * (*get_osb)(struct ocfs2_lock_res *);
/*
* Optionally called in the downconvert thread after a
* successful downconvert. The lockres will not be referenced
* after this callback is called, so it is safe to free
* memory, etc.
*
* The exact semantics of when this is called are controlled
* by ->downconvert_worker()
*/
void (*post_unlock)(struct ocfs2_super *, struct ocfs2_lock_res *);
/*
* Allow a lock type to add checks to determine whether it is
* safe to downconvert a lock. Return 0 to re-queue the
* downconvert at a later time, nonzero to continue.
*
* For most locks, the default checks that there are no
* incompatible holders are sufficient.
*
* Called with the lockres spinlock held.
*/
int (*check_downconvert)(struct ocfs2_lock_res *, int);
/*
* Allows a lock type to populate the lock value block. This
* is called on downconvert, and when we drop a lock.
*
* Locks that want to use this should set LOCK_TYPE_USES_LVB
* in the flags field.
*
* Called with the lockres spinlock held.
*/
void (*set_lvb)(struct ocfs2_lock_res *);
/*
* Called from the downconvert thread when it is determined
* that a lock will be downconverted. This is called without
* any locks held so the function can do work that might
* schedule (syncing out data, etc).
*
* This should return any one of the ocfs2_unblock_action
* values, depending on what it wants the thread to do.
*/
int (*downconvert_worker)(struct ocfs2_lock_res *, int);
/*
* LOCK_TYPE_* flags which describe the specific requirements
* of a lock type. Descriptions of each individual flag follow.
*/
int flags;
};
/*
* Some locks want to "refresh" potentially stale data when a
* meaningful (PRMODE or EXMODE) lock level is first obtained. If this
* flag is set, the OCFS2_LOCK_NEEDS_REFRESH flag will be set on the
* individual lockres l_flags member from the ast function. It is
* expected that the locking wrapper will clear the
* OCFS2_LOCK_NEEDS_REFRESH flag when done.
*/
#define LOCK_TYPE_REQUIRES_REFRESH 0x1
/*
* Indicate that a lock type makes use of the lock value block. The
* ->set_lvb lock type callback must be defined.
*/
#define LOCK_TYPE_USES_LVB 0x2
static struct ocfs2_lock_res_ops ocfs2_inode_rw_lops = {
.get_osb = ocfs2_get_inode_osb,
.flags = 0,
};
static struct ocfs2_lock_res_ops ocfs2_inode_inode_lops = {
.get_osb = ocfs2_get_inode_osb,
.check_downconvert = ocfs2_check_meta_downconvert,
.set_lvb = ocfs2_set_meta_lvb,
.downconvert_worker = ocfs2_data_convert_worker,
.flags = LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
};
static struct ocfs2_lock_res_ops ocfs2_super_lops = {
.flags = LOCK_TYPE_REQUIRES_REFRESH,
};
static struct ocfs2_lock_res_ops ocfs2_rename_lops = {
.flags = 0,
};
static struct ocfs2_lock_res_ops ocfs2_dentry_lops = {
.get_osb = ocfs2_get_dentry_osb,
.post_unlock = ocfs2_dentry_post_unlock,
.downconvert_worker = ocfs2_dentry_convert_worker,
.flags = 0,
};
static struct ocfs2_lock_res_ops ocfs2_inode_open_lops = {
.get_osb = ocfs2_get_inode_osb,
.flags = 0,
};
static struct ocfs2_lock_res_ops ocfs2_flock_lops = {
.get_osb = ocfs2_get_file_osb,
.flags = 0,
};
static inline int ocfs2_is_inode_lock(struct ocfs2_lock_res *lockres)
{
return lockres->l_type == OCFS2_LOCK_TYPE_META ||
lockres->l_type == OCFS2_LOCK_TYPE_RW ||
lockres->l_type == OCFS2_LOCK_TYPE_OPEN;
}
static inline struct inode *ocfs2_lock_res_inode(struct ocfs2_lock_res *lockres)
{
BUG_ON(!ocfs2_is_inode_lock(lockres));
return (struct inode *) lockres->l_priv;
}
static inline struct ocfs2_dentry_lock *ocfs2_lock_res_dl(struct ocfs2_lock_res *lockres)
{
BUG_ON(lockres->l_type != OCFS2_LOCK_TYPE_DENTRY);
return (struct ocfs2_dentry_lock *)lockres->l_priv;
}
static inline struct ocfs2_super *ocfs2_get_lockres_osb(struct ocfs2_lock_res *lockres)
{
if (lockres->l_ops->get_osb)
return lockres->l_ops->get_osb(lockres);
return (struct ocfs2_super *)lockres->l_priv;
}
static int ocfs2_lock_create(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int level,
u32 dlm_flags);
static inline int ocfs2_may_continue_on_blocked_lock(struct ocfs2_lock_res *lockres,
int wanted);
static void ocfs2_cluster_unlock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int level);
static inline void ocfs2_generic_handle_downconvert_action(struct ocfs2_lock_res *lockres);
static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lockres);
static inline void ocfs2_generic_handle_attach_action(struct ocfs2_lock_res *lockres);
static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres, int level);
static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres);
static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
int convert);
#define ocfs2_log_dlm_error(_func, _err, _lockres) do { \
mlog(ML_ERROR, "DLM error %d while calling %s on resource %s\n", \
_err, _func, _lockres->l_name); \
} while (0)
static int ocfs2_downconvert_thread(void *arg);
static void ocfs2_downconvert_on_unlock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres);
static int ocfs2_inode_lock_update(struct inode *inode,
struct buffer_head **bh);
static void ocfs2_drop_osb_locks(struct ocfs2_super *osb);
static inline int ocfs2_highest_compat_lock_level(int level);
static unsigned int ocfs2_prepare_downconvert(struct ocfs2_lock_res *lockres,
int new_level);
static int ocfs2_downconvert_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int new_level,
int lvb,
unsigned int generation);
static int ocfs2_prepare_cancel_convert(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres);
static int ocfs2_cancel_convert(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres);
static void ocfs2_build_lock_name(enum ocfs2_lock_type type,
u64 blkno,
u32 generation,
char *name)
{
int len;
mlog_entry_void();
BUG_ON(type >= OCFS2_NUM_LOCK_TYPES);
len = snprintf(name, OCFS2_LOCK_ID_MAX_LEN, "%c%s%016llx%08x",
ocfs2_lock_type_char(type), OCFS2_LOCK_ID_PAD,
(long long)blkno, generation);
BUG_ON(len != (OCFS2_LOCK_ID_MAX_LEN - 1));
mlog(0, "built lock resource with name: %s\n", name);
mlog_exit_void();
}
static DEFINE_SPINLOCK(ocfs2_dlm_tracking_lock);
static void ocfs2_add_lockres_tracking(struct ocfs2_lock_res *res,
struct ocfs2_dlm_debug *dlm_debug)
{
mlog(0, "Add tracking for lockres %s\n", res->l_name);
spin_lock(&ocfs2_dlm_tracking_lock);
list_add(&res->l_debug_list, &dlm_debug->d_lockres_tracking);
spin_unlock(&ocfs2_dlm_tracking_lock);
}
static void ocfs2_remove_lockres_tracking(struct ocfs2_lock_res *res)
{
spin_lock(&ocfs2_dlm_tracking_lock);
if (!list_empty(&res->l_debug_list))
list_del_init(&res->l_debug_list);
spin_unlock(&ocfs2_dlm_tracking_lock);
}
#ifdef CONFIG_OCFS2_FS_STATS
static void ocfs2_init_lock_stats(struct ocfs2_lock_res *res)
{
res->l_lock_num_prmode = 0;
res->l_lock_num_prmode_failed = 0;
res->l_lock_total_prmode = 0;
res->l_lock_max_prmode = 0;
res->l_lock_num_exmode = 0;
res->l_lock_num_exmode_failed = 0;
res->l_lock_total_exmode = 0;
res->l_lock_max_exmode = 0;
res->l_lock_refresh = 0;
}
static void ocfs2_update_lock_stats(struct ocfs2_lock_res *res, int level,
struct ocfs2_mask_waiter *mw, int ret)
{
unsigned long long *num, *sum;
unsigned int *max, *failed;
struct timespec ts = current_kernel_time();
unsigned long long time = timespec_to_ns(&ts) - mw->mw_lock_start;
if (level == LKM_PRMODE) {
num = &res->l_lock_num_prmode;
sum = &res->l_lock_total_prmode;
max = &res->l_lock_max_prmode;
failed = &res->l_lock_num_prmode_failed;
} else if (level == LKM_EXMODE) {
num = &res->l_lock_num_exmode;
sum = &res->l_lock_total_exmode;
max = &res->l_lock_max_exmode;
failed = &res->l_lock_num_exmode_failed;
} else
return;
(*num)++;
(*sum) += time;
if (time > *max)
*max = time;
if (ret)
(*failed)++;
}
static inline void ocfs2_track_lock_refresh(struct ocfs2_lock_res *lockres)
{
lockres->l_lock_refresh++;
}
static inline void ocfs2_init_start_time(struct ocfs2_mask_waiter *mw)
{
struct timespec ts = current_kernel_time();
mw->mw_lock_start = timespec_to_ns(&ts);
}
#else
static inline void ocfs2_init_lock_stats(struct ocfs2_lock_res *res)
{
}
static inline void ocfs2_update_lock_stats(struct ocfs2_lock_res *res,
int level, struct ocfs2_mask_waiter *mw, int ret)
{
}
static inline void ocfs2_track_lock_refresh(struct ocfs2_lock_res *lockres)
{
}
static inline void ocfs2_init_start_time(struct ocfs2_mask_waiter *mw)
{
}
#endif
static void ocfs2_lock_res_init_common(struct ocfs2_super *osb,
struct ocfs2_lock_res *res,
enum ocfs2_lock_type type,
struct ocfs2_lock_res_ops *ops,
void *priv)
{
res->l_type = type;
res->l_ops = ops;
res->l_priv = priv;
res->l_level = DLM_LOCK_IV;
res->l_requested = DLM_LOCK_IV;
res->l_blocking = DLM_LOCK_IV;
res->l_action = OCFS2_AST_INVALID;
res->l_unlock_action = OCFS2_UNLOCK_INVALID;
res->l_flags = OCFS2_LOCK_INITIALIZED;
ocfs2_add_lockres_tracking(res, osb->osb_dlm_debug);
ocfs2_init_lock_stats(res);
}
void ocfs2_lock_res_init_once(struct ocfs2_lock_res *res)
{
/* This also clears out the lock status block */
memset(res, 0, sizeof(struct ocfs2_lock_res));
spin_lock_init(&res->l_lock);
init_waitqueue_head(&res->l_event);
INIT_LIST_HEAD(&res->l_blocked_list);
INIT_LIST_HEAD(&res->l_mask_waiters);
}
void ocfs2_inode_lock_res_init(struct ocfs2_lock_res *res,
enum ocfs2_lock_type type,
unsigned int generation,
struct inode *inode)
{
struct ocfs2_lock_res_ops *ops;
switch(type) {
case OCFS2_LOCK_TYPE_RW:
ops = &ocfs2_inode_rw_lops;
break;
case OCFS2_LOCK_TYPE_META:
ops = &ocfs2_inode_inode_lops;
break;
case OCFS2_LOCK_TYPE_OPEN:
ops = &ocfs2_inode_open_lops;
break;
default:
mlog_bug_on_msg(1, "type: %d\n", type);
ops = NULL; /* thanks, gcc */
break;
};
ocfs2_build_lock_name(type, OCFS2_I(inode)->ip_blkno,
generation, res->l_name);
ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), res, type, ops, inode);
}
static struct ocfs2_super *ocfs2_get_inode_osb(struct ocfs2_lock_res *lockres)
{
struct inode *inode = ocfs2_lock_res_inode(lockres);
return OCFS2_SB(inode->i_sb);
}
static struct ocfs2_super *ocfs2_get_file_osb(struct ocfs2_lock_res *lockres)
{
struct ocfs2_file_private *fp = lockres->l_priv;
return OCFS2_SB(fp->fp_file->f_mapping->host->i_sb);
}
static __u64 ocfs2_get_dentry_lock_ino(struct ocfs2_lock_res *lockres)
{
__be64 inode_blkno_be;
memcpy(&inode_blkno_be, &lockres->l_name[OCFS2_DENTRY_LOCK_INO_START],
sizeof(__be64));
return be64_to_cpu(inode_blkno_be);
}
static struct ocfs2_super *ocfs2_get_dentry_osb(struct ocfs2_lock_res *lockres)
{
struct ocfs2_dentry_lock *dl = lockres->l_priv;
return OCFS2_SB(dl->dl_inode->i_sb);
}
void ocfs2_dentry_lock_res_init(struct ocfs2_dentry_lock *dl,
u64 parent, struct inode *inode)
{
int len;
u64 inode_blkno = OCFS2_I(inode)->ip_blkno;
__be64 inode_blkno_be = cpu_to_be64(inode_blkno);
struct ocfs2_lock_res *lockres = &dl->dl_lockres;
ocfs2_lock_res_init_once(lockres);
/*
* Unfortunately, the standard lock naming scheme won't work
* here because we have two 16 byte values to use. Instead,
* we'll stuff the inode number as a binary value. We still
* want error prints to show something without garbling the
* display, so drop a null byte in there before the inode
* number. A future version of OCFS2 will likely use all
* binary lock names. The stringified names have been a
* tremendous aid in debugging, but now that the debugfs
* interface exists, we can mangle things there if need be.
*
* NOTE: We also drop the standard "pad" value (the total lock
* name size stays the same though - the last part is all
* zeros due to the memset in ocfs2_lock_res_init_once()
*/
len = snprintf(lockres->l_name, OCFS2_DENTRY_LOCK_INO_START,
"%c%016llx",
ocfs2_lock_type_char(OCFS2_LOCK_TYPE_DENTRY),
(long long)parent);
BUG_ON(len != (OCFS2_DENTRY_LOCK_INO_START - 1));
memcpy(&lockres->l_name[OCFS2_DENTRY_LOCK_INO_START], &inode_blkno_be,
sizeof(__be64));
ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), lockres,
OCFS2_LOCK_TYPE_DENTRY, &ocfs2_dentry_lops,
dl);
}
static void ocfs2_super_lock_res_init(struct ocfs2_lock_res *res,
struct ocfs2_super *osb)
{
/* Superblock lockres doesn't come from a slab so we call init
* once on it manually. */
ocfs2_lock_res_init_once(res);
ocfs2_build_lock_name(OCFS2_LOCK_TYPE_SUPER, OCFS2_SUPER_BLOCK_BLKNO,
0, res->l_name);
ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_SUPER,
&ocfs2_super_lops, osb);
}
static void ocfs2_rename_lock_res_init(struct ocfs2_lock_res *res,
struct ocfs2_super *osb)
{
/* Rename lockres doesn't come from a slab so we call init
* once on it manually. */
ocfs2_lock_res_init_once(res);
ocfs2_build_lock_name(OCFS2_LOCK_TYPE_RENAME, 0, 0, res->l_name);
ocfs2_lock_res_init_common(osb, res, OCFS2_LOCK_TYPE_RENAME,
&ocfs2_rename_lops, osb);
}
void ocfs2_file_lock_res_init(struct ocfs2_lock_res *lockres,
struct ocfs2_file_private *fp)
{
struct inode *inode = fp->fp_file->f_mapping->host;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
ocfs2_lock_res_init_once(lockres);
ocfs2_build_lock_name(OCFS2_LOCK_TYPE_FLOCK, oi->ip_blkno,
inode->i_generation, lockres->l_name);
ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), lockres,
OCFS2_LOCK_TYPE_FLOCK, &ocfs2_flock_lops,
fp);
lockres->l_flags |= OCFS2_LOCK_NOCACHE;
}
void ocfs2_lock_res_free(struct ocfs2_lock_res *res)
{
mlog_entry_void();
if (!(res->l_flags & OCFS2_LOCK_INITIALIZED))
return;
ocfs2_remove_lockres_tracking(res);
mlog_bug_on_msg(!list_empty(&res->l_blocked_list),
"Lockres %s is on the blocked list\n",
res->l_name);
mlog_bug_on_msg(!list_empty(&res->l_mask_waiters),
"Lockres %s has mask waiters pending\n",
res->l_name);
mlog_bug_on_msg(spin_is_locked(&res->l_lock),
"Lockres %s is locked\n",
res->l_name);
mlog_bug_on_msg(res->l_ro_holders,
"Lockres %s has %u ro holders\n",
res->l_name, res->l_ro_holders);
mlog_bug_on_msg(res->l_ex_holders,
"Lockres %s has %u ex holders\n",
res->l_name, res->l_ex_holders);
/* Need to clear out the lock status block for the dlm */
memset(&res->l_lksb, 0, sizeof(res->l_lksb));
res->l_flags = 0UL;
mlog_exit_void();
}
static inline void ocfs2_inc_holders(struct ocfs2_lock_res *lockres,
int level)
{
mlog_entry_void();
BUG_ON(!lockres);
switch(level) {
case DLM_LOCK_EX:
lockres->l_ex_holders++;
break;
case DLM_LOCK_PR:
lockres->l_ro_holders++;
break;
default:
BUG();
}
mlog_exit_void();
}
static inline void ocfs2_dec_holders(struct ocfs2_lock_res *lockres,
int level)
{
mlog_entry_void();
BUG_ON(!lockres);
switch(level) {
case DLM_LOCK_EX:
BUG_ON(!lockres->l_ex_holders);
lockres->l_ex_holders--;
break;
case DLM_LOCK_PR:
BUG_ON(!lockres->l_ro_holders);
lockres->l_ro_holders--;
break;
default:
BUG();
}
mlog_exit_void();
}
/* WARNING: This function lives in a world where the only three lock
* levels are EX, PR, and NL. It *will* have to be adjusted when more
* lock types are added. */
static inline int ocfs2_highest_compat_lock_level(int level)
{
int new_level = DLM_LOCK_EX;
if (level == DLM_LOCK_EX)
new_level = DLM_LOCK_NL;
else if (level == DLM_LOCK_PR)
new_level = DLM_LOCK_PR;
return new_level;
}
static void lockres_set_flags(struct ocfs2_lock_res *lockres,
unsigned long newflags)
{
struct ocfs2_mask_waiter *mw, *tmp;
assert_spin_locked(&lockres->l_lock);
lockres->l_flags = newflags;
list_for_each_entry_safe(mw, tmp, &lockres->l_mask_waiters, mw_item) {
if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
continue;
list_del_init(&mw->mw_item);
mw->mw_status = 0;
complete(&mw->mw_complete);
}
}
static void lockres_or_flags(struct ocfs2_lock_res *lockres, unsigned long or)
{
lockres_set_flags(lockres, lockres->l_flags | or);
}
static void lockres_clear_flags(struct ocfs2_lock_res *lockres,
unsigned long clear)
{
lockres_set_flags(lockres, lockres->l_flags & ~clear);
}
static inline void ocfs2_generic_handle_downconvert_action(struct ocfs2_lock_res *lockres)
{
mlog_entry_void();
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_ATTACHED));
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED));
BUG_ON(lockres->l_blocking <= DLM_LOCK_NL);
lockres->l_level = lockres->l_requested;
if (lockres->l_level <=
ocfs2_highest_compat_lock_level(lockres->l_blocking)) {
lockres->l_blocking = DLM_LOCK_NL;
lockres_clear_flags(lockres, OCFS2_LOCK_BLOCKED);
}
lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
mlog_exit_void();
}
static inline void ocfs2_generic_handle_convert_action(struct ocfs2_lock_res *lockres)
{
mlog_entry_void();
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_ATTACHED));
/* Convert from RO to EX doesn't really need anything as our
* information is already up to data. Convert from NL to
* *anything* however should mark ourselves as needing an
* update */
if (lockres->l_level == DLM_LOCK_NL &&
lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
lockres_or_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
lockres->l_level = lockres->l_requested;
lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
mlog_exit_void();
}
static inline void ocfs2_generic_handle_attach_action(struct ocfs2_lock_res *lockres)
{
mlog_entry_void();
BUG_ON((!(lockres->l_flags & OCFS2_LOCK_BUSY)));
BUG_ON(lockres->l_flags & OCFS2_LOCK_ATTACHED);
if (lockres->l_requested > DLM_LOCK_NL &&
!(lockres->l_flags & OCFS2_LOCK_LOCAL) &&
lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
lockres_or_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
lockres->l_level = lockres->l_requested;
lockres_or_flags(lockres, OCFS2_LOCK_ATTACHED);
lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
mlog_exit_void();
}
static int ocfs2_generic_handle_bast(struct ocfs2_lock_res *lockres,
int level)
{
int needs_downconvert = 0;
mlog_entry_void();
assert_spin_locked(&lockres->l_lock);
lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED);
if (level > lockres->l_blocking) {
/* only schedule a downconvert if we haven't already scheduled
* one that goes low enough to satisfy the level we're
* blocking. this also catches the case where we get
* duplicate BASTs */
if (ocfs2_highest_compat_lock_level(level) <
ocfs2_highest_compat_lock_level(lockres->l_blocking))
needs_downconvert = 1;
lockres->l_blocking = level;
}
mlog_exit(needs_downconvert);
return needs_downconvert;
}
/*
* OCFS2_LOCK_PENDING and l_pending_gen.
*
* Why does OCFS2_LOCK_PENDING exist? To close a race between setting
* OCFS2_LOCK_BUSY and calling ocfs2_dlm_lock(). See ocfs2_unblock_lock()
* for more details on the race.
*
* OCFS2_LOCK_PENDING closes the race quite nicely. However, it introduces
* a race on itself. In o2dlm, we can get the ast before ocfs2_dlm_lock()
* returns. The ast clears OCFS2_LOCK_BUSY, and must therefore clear
* OCFS2_LOCK_PENDING at the same time. When ocfs2_dlm_lock() returns,
* the caller is going to try to clear PENDING again. If nothing else is
* happening, __lockres_clear_pending() sees PENDING is unset and does
* nothing.
*
* But what if another path (eg downconvert thread) has just started a
* new locking action? The other path has re-set PENDING. Our path
* cannot clear PENDING, because that will re-open the original race
* window.
*
* [Example]
*
* ocfs2_meta_lock()
* ocfs2_cluster_lock()
* set BUSY
* set PENDING
* drop l_lock
* ocfs2_dlm_lock()
* ocfs2_locking_ast() ocfs2_downconvert_thread()
* clear PENDING ocfs2_unblock_lock()
* take_l_lock
* !BUSY
* ocfs2_prepare_downconvert()
* set BUSY
* set PENDING
* drop l_lock
* take l_lock
* clear PENDING
* drop l_lock
* <window>
* ocfs2_dlm_lock()
*
* So as you can see, we now have a window where l_lock is not held,
* PENDING is not set, and ocfs2_dlm_lock() has not been called.
*
* The core problem is that ocfs2_cluster_lock() has cleared the PENDING
* set by ocfs2_prepare_downconvert(). That wasn't nice.
*
* To solve this we introduce l_pending_gen. A call to
* lockres_clear_pending() will only do so when it is passed a generation
* number that matches the lockres. lockres_set_pending() will return the
* current generation number. When ocfs2_cluster_lock() goes to clear
* PENDING, it passes the generation it got from set_pending(). In our
* example above, the generation numbers will *not* match. Thus,
* ocfs2_cluster_lock() will not clear the PENDING set by
* ocfs2_prepare_downconvert().
*/
/* Unlocked version for ocfs2_locking_ast() */
static void __lockres_clear_pending(struct ocfs2_lock_res *lockres,
unsigned int generation,
struct ocfs2_super *osb)
{
assert_spin_locked(&lockres->l_lock);
/*
* The ast and locking functions can race us here. The winner
* will clear pending, the loser will not.
*/
if (!(lockres->l_flags & OCFS2_LOCK_PENDING) ||
(lockres->l_pending_gen != generation))
return;
lockres_clear_flags(lockres, OCFS2_LOCK_PENDING);
lockres->l_pending_gen++;
/*
* The downconvert thread may have skipped us because we
* were PENDING. Wake it up.
*/
if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
ocfs2_wake_downconvert_thread(osb);
}
/* Locked version for callers of ocfs2_dlm_lock() */
static void lockres_clear_pending(struct ocfs2_lock_res *lockres,
unsigned int generation,
struct ocfs2_super *osb)
{
unsigned long flags;
spin_lock_irqsave(&lockres->l_lock, flags);
__lockres_clear_pending(lockres, generation, osb);
spin_unlock_irqrestore(&lockres->l_lock, flags);
}
static unsigned int lockres_set_pending(struct ocfs2_lock_res *lockres)
{
assert_spin_locked(&lockres->l_lock);
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BUSY));
lockres_or_flags(lockres, OCFS2_LOCK_PENDING);
return lockres->l_pending_gen;
}
static void ocfs2_blocking_ast(void *opaque, int level)
{
struct ocfs2_lock_res *lockres = opaque;
struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
int needs_downconvert;
unsigned long flags;
BUG_ON(level <= DLM_LOCK_NL);
mlog(0, "BAST fired for lockres %s, blocking %d, level %d type %s\n",
lockres->l_name, level, lockres->l_level,
ocfs2_lock_type_string(lockres->l_type));
/*
* We can skip the bast for locks which don't enable caching -
* they'll be dropped at the earliest possible time anyway.
*/
if (lockres->l_flags & OCFS2_LOCK_NOCACHE)
return;
spin_lock_irqsave(&lockres->l_lock, flags);
needs_downconvert = ocfs2_generic_handle_bast(lockres, level);
if (needs_downconvert)
ocfs2_schedule_blocked_lock(osb, lockres);
spin_unlock_irqrestore(&lockres->l_lock, flags);
wake_up(&lockres->l_event);
ocfs2_wake_downconvert_thread(osb);
}
static void ocfs2_locking_ast(void *opaque)
{
struct ocfs2_lock_res *lockres = opaque;
struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
unsigned long flags;
int status;
spin_lock_irqsave(&lockres->l_lock, flags);
status = ocfs2_dlm_lock_status(&lockres->l_lksb);
if (status == -EAGAIN) {
lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
goto out;
}
if (status) {
mlog(ML_ERROR, "lockres %s: lksb status value of %d!\n",
lockres->l_name, status);
spin_unlock_irqrestore(&lockres->l_lock, flags);
return;
}
switch(lockres->l_action) {
case OCFS2_AST_ATTACH:
ocfs2_generic_handle_attach_action(lockres);
lockres_clear_flags(lockres, OCFS2_LOCK_LOCAL);
break;
case OCFS2_AST_CONVERT:
ocfs2_generic_handle_convert_action(lockres);
break;
case OCFS2_AST_DOWNCONVERT:
ocfs2_generic_handle_downconvert_action(lockres);
break;
default:
mlog(ML_ERROR, "lockres %s: ast fired with invalid action: %u "
"lockres flags = 0x%lx, unlock action: %u\n",
lockres->l_name, lockres->l_action, lockres->l_flags,
lockres->l_unlock_action);
BUG();
}
out:
/* set it to something invalid so if we get called again we
* can catch it. */
lockres->l_action = OCFS2_AST_INVALID;
/* Did we try to cancel this lock? Clear that state */
if (lockres->l_unlock_action == OCFS2_UNLOCK_CANCEL_CONVERT)
lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
/*
* We may have beaten the locking functions here. We certainly
* know that dlm_lock() has been called :-)
* Because we can't have two lock calls in flight at once, we
* can use lockres->l_pending_gen.
*/
__lockres_clear_pending(lockres, lockres->l_pending_gen, osb);
wake_up(&lockres->l_event);
spin_unlock_irqrestore(&lockres->l_lock, flags);
}
static inline void ocfs2_recover_from_dlm_error(struct ocfs2_lock_res *lockres,
int convert)
{
unsigned long flags;
mlog_entry_void();
spin_lock_irqsave(&lockres->l_lock, flags);
lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
if (convert)
lockres->l_action = OCFS2_AST_INVALID;
else
lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
spin_unlock_irqrestore(&lockres->l_lock, flags);
wake_up(&lockres->l_event);
mlog_exit_void();
}
/* Note: If we detect another process working on the lock (i.e.,
* OCFS2_LOCK_BUSY), we'll bail out returning 0. It's up to the caller
* to do the right thing in that case.
*/
static int ocfs2_lock_create(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int level,
u32 dlm_flags)
{
int ret = 0;
unsigned long flags;
unsigned int gen;
mlog_entry_void();
mlog(0, "lock %s, level = %d, flags = %u\n", lockres->l_name, level,
dlm_flags);
spin_lock_irqsave(&lockres->l_lock, flags);
if ((lockres->l_flags & OCFS2_LOCK_ATTACHED) ||
(lockres->l_flags & OCFS2_LOCK_BUSY)) {
spin_unlock_irqrestore(&lockres->l_lock, flags);
goto bail;
}
lockres->l_action = OCFS2_AST_ATTACH;
lockres->l_requested = level;
lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
gen = lockres_set_pending(lockres);
spin_unlock_irqrestore(&lockres->l_lock, flags);
ret = ocfs2_dlm_lock(osb->cconn,
level,
&lockres->l_lksb,
dlm_flags,
lockres->l_name,
OCFS2_LOCK_ID_MAX_LEN - 1,
lockres);
lockres_clear_pending(lockres, gen, osb);
if (ret) {
ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
ocfs2_recover_from_dlm_error(lockres, 1);
}
mlog(0, "lock %s, return from ocfs2_dlm_lock\n", lockres->l_name);
bail:
mlog_exit(ret);
return ret;
}
static inline int ocfs2_check_wait_flag(struct ocfs2_lock_res *lockres,
int flag)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&lockres->l_lock, flags);
ret = lockres->l_flags & flag;
spin_unlock_irqrestore(&lockres->l_lock, flags);
return ret;
}
static inline void ocfs2_wait_on_busy_lock(struct ocfs2_lock_res *lockres)
{
wait_event(lockres->l_event,
!ocfs2_check_wait_flag(lockres, OCFS2_LOCK_BUSY));
}
static inline void ocfs2_wait_on_refreshing_lock(struct ocfs2_lock_res *lockres)
{
wait_event(lockres->l_event,
!ocfs2_check_wait_flag(lockres, OCFS2_LOCK_REFRESHING));
}
/* predict what lock level we'll be dropping down to on behalf
* of another node, and return true if the currently wanted
* level will be compatible with it. */
static inline int ocfs2_may_continue_on_blocked_lock(struct ocfs2_lock_res *lockres,
int wanted)
{
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED));
return wanted <= ocfs2_highest_compat_lock_level(lockres->l_blocking);
}
static void ocfs2_init_mask_waiter(struct ocfs2_mask_waiter *mw)
{
INIT_LIST_HEAD(&mw->mw_item);
init_completion(&mw->mw_complete);
ocfs2_init_start_time(mw);
}
static int ocfs2_wait_for_mask(struct ocfs2_mask_waiter *mw)
{
wait_for_completion(&mw->mw_complete);
/* Re-arm the completion in case we want to wait on it again */
INIT_COMPLETION(mw->mw_complete);
return mw->mw_status;
}
static void lockres_add_mask_waiter(struct ocfs2_lock_res *lockres,
struct ocfs2_mask_waiter *mw,
unsigned long mask,
unsigned long goal)
{
BUG_ON(!list_empty(&mw->mw_item));
assert_spin_locked(&lockres->l_lock);
list_add_tail(&mw->mw_item, &lockres->l_mask_waiters);
mw->mw_mask = mask;
mw->mw_goal = goal;
}
/* returns 0 if the mw that was removed was already satisfied, -EBUSY
* if the mask still hadn't reached its goal */
static int lockres_remove_mask_waiter(struct ocfs2_lock_res *lockres,
struct ocfs2_mask_waiter *mw)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&lockres->l_lock, flags);
if (!list_empty(&mw->mw_item)) {
if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
ret = -EBUSY;
list_del_init(&mw->mw_item);
init_completion(&mw->mw_complete);
}
spin_unlock_irqrestore(&lockres->l_lock, flags);
return ret;
}
static int ocfs2_wait_for_mask_interruptible(struct ocfs2_mask_waiter *mw,
struct ocfs2_lock_res *lockres)
{
int ret;
ret = wait_for_completion_interruptible(&mw->mw_complete);
if (ret)
lockres_remove_mask_waiter(lockres, mw);
else
ret = mw->mw_status;
/* Re-arm the completion in case we want to wait on it again */
INIT_COMPLETION(mw->mw_complete);
return ret;
}
static int ocfs2_cluster_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int level,
u32 lkm_flags,
int arg_flags)
{
struct ocfs2_mask_waiter mw;
int wait, catch_signals = !(osb->s_mount_opt & OCFS2_MOUNT_NOINTR);
int ret = 0; /* gcc doesn't realize wait = 1 guarantees ret is set */
unsigned long flags;
unsigned int gen;
int noqueue_attempted = 0;
mlog_entry_void();
ocfs2_init_mask_waiter(&mw);
if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
lkm_flags |= DLM_LKF_VALBLK;
again:
wait = 0;
if (catch_signals && signal_pending(current)) {
ret = -ERESTARTSYS;
goto out;
}
spin_lock_irqsave(&lockres->l_lock, flags);
mlog_bug_on_msg(lockres->l_flags & OCFS2_LOCK_FREEING,
"Cluster lock called on freeing lockres %s! flags "
"0x%lx\n", lockres->l_name, lockres->l_flags);
/* We only compare against the currently granted level
* here. If the lock is blocked waiting on a downconvert,
* we'll get caught below. */
if (lockres->l_flags & OCFS2_LOCK_BUSY &&
level > lockres->l_level) {
/* is someone sitting in dlm_lock? If so, wait on
* them. */
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
wait = 1;
goto unlock;
}
if (lockres->l_flags & OCFS2_LOCK_BLOCKED &&
!ocfs2_may_continue_on_blocked_lock(lockres, level)) {
/* is the lock is currently blocked on behalf of
* another node */
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BLOCKED, 0);
wait = 1;
goto unlock;
}
if (level > lockres->l_level) {
if (noqueue_attempted > 0) {
ret = -EAGAIN;
goto unlock;
}
if (lkm_flags & DLM_LKF_NOQUEUE)
noqueue_attempted = 1;
if (lockres->l_action != OCFS2_AST_INVALID)
mlog(ML_ERROR, "lockres %s has action %u pending\n",
lockres->l_name, lockres->l_action);
if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
lockres->l_action = OCFS2_AST_ATTACH;
lkm_flags &= ~DLM_LKF_CONVERT;
} else {
lockres->l_action = OCFS2_AST_CONVERT;
lkm_flags |= DLM_LKF_CONVERT;
}
lockres->l_requested = level;
lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
gen = lockres_set_pending(lockres);
spin_unlock_irqrestore(&lockres->l_lock, flags);
BUG_ON(level == DLM_LOCK_IV);
BUG_ON(level == DLM_LOCK_NL);
mlog(0, "lock %s, convert from %d to level = %d\n",
lockres->l_name, lockres->l_level, level);
/* call dlm_lock to upgrade lock now */
ret = ocfs2_dlm_lock(osb->cconn,
level,
&lockres->l_lksb,
lkm_flags,
lockres->l_name,
OCFS2_LOCK_ID_MAX_LEN - 1,
lockres);
lockres_clear_pending(lockres, gen, osb);
if (ret) {
if (!(lkm_flags & DLM_LKF_NOQUEUE) ||
(ret != -EAGAIN)) {
ocfs2_log_dlm_error("ocfs2_dlm_lock",
ret, lockres);
}
ocfs2_recover_from_dlm_error(lockres, 1);
goto out;
}
mlog(0, "lock %s, successfull return from ocfs2_dlm_lock\n",
lockres->l_name);
/* At this point we've gone inside the dlm and need to
* complete our work regardless. */
catch_signals = 0;
/* wait for busy to clear and carry on */
goto again;
}
/* Ok, if we get here then we're good to go. */
ocfs2_inc_holders(lockres, level);
ret = 0;
unlock:
spin_unlock_irqrestore(&lockres->l_lock, flags);
out:
/*
* This is helping work around a lock inversion between the page lock
* and dlm locks. One path holds the page lock while calling aops
* which block acquiring dlm locks. The voting thread holds dlm
* locks while acquiring page locks while down converting data locks.
* This block is helping an aop path notice the inversion and back
* off to unlock its page lock before trying the dlm lock again.
*/
if (wait && arg_flags & OCFS2_LOCK_NONBLOCK &&
mw.mw_mask & (OCFS2_LOCK_BUSY|OCFS2_LOCK_BLOCKED)) {
wait = 0;
if (lockres_remove_mask_waiter(lockres, &mw))
ret = -EAGAIN;
else
goto again;
}
if (wait) {
ret = ocfs2_wait_for_mask(&mw);
if (ret == 0)
goto again;
mlog_errno(ret);
}
ocfs2_update_lock_stats(lockres, level, &mw, ret);
mlog_exit(ret);
return ret;
}
static void ocfs2_cluster_unlock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int level)
{
unsigned long flags;
mlog_entry_void();
spin_lock_irqsave(&lockres->l_lock, flags);
ocfs2_dec_holders(lockres, level);
ocfs2_downconvert_on_unlock(osb, lockres);
spin_unlock_irqrestore(&lockres->l_lock, flags);
mlog_exit_void();
}
static int ocfs2_create_new_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int ex,
int local)
{
int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
unsigned long flags;
u32 lkm_flags = local ? DLM_LKF_LOCAL : 0;
spin_lock_irqsave(&lockres->l_lock, flags);
BUG_ON(lockres->l_flags & OCFS2_LOCK_ATTACHED);
lockres_or_flags(lockres, OCFS2_LOCK_LOCAL);
spin_unlock_irqrestore(&lockres->l_lock, flags);
return ocfs2_lock_create(osb, lockres, level, lkm_flags);
}
/* Grants us an EX lock on the data and metadata resources, skipping
* the normal cluster directory lookup. Use this ONLY on newly created
* inodes which other nodes can't possibly see, and which haven't been
* hashed in the inode hash yet. This can give us a good performance
* increase as it'll skip the network broadcast normally associated
* with creating a new lock resource. */
int ocfs2_create_new_inode_locks(struct inode *inode)
{
int ret;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
BUG_ON(!inode);
BUG_ON(!ocfs2_inode_is_new(inode));
mlog_entry_void();
mlog(0, "Inode %llu\n", (unsigned long long)OCFS2_I(inode)->ip_blkno);
/* NOTE: That we don't increment any of the holder counts, nor
* do we add anything to a journal handle. Since this is
* supposed to be a new inode which the cluster doesn't know
* about yet, there is no need to. As far as the LVB handling
* is concerned, this is basically like acquiring an EX lock
* on a resource which has an invalid one -- we'll set it
* valid when we release the EX. */
ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_rw_lockres, 1, 1);
if (ret) {
mlog_errno(ret);
goto bail;
}
/*
* We don't want to use DLM_LKF_LOCAL on a meta data lock as they
* don't use a generation in their lock names.
*/
ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_inode_lockres, 1, 0);
if (ret) {
mlog_errno(ret);
goto bail;
}
ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_open_lockres, 0, 0);
if (ret) {
mlog_errno(ret);
goto bail;
}
bail:
mlog_exit(ret);
return ret;
}
int ocfs2_rw_lock(struct inode *inode, int write)
{
int status, level;
struct ocfs2_lock_res *lockres;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
BUG_ON(!inode);
mlog_entry_void();
mlog(0, "inode %llu take %s RW lock\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno,
write ? "EXMODE" : "PRMODE");
if (ocfs2_mount_local(osb))
return 0;
lockres = &OCFS2_I(inode)->ip_rw_lockres;
level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, level, 0,
0);
if (status < 0)
mlog_errno(status);
mlog_exit(status);
return status;
}
void ocfs2_rw_unlock(struct inode *inode, int write)
{
int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_rw_lockres;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
mlog_entry_void();
mlog(0, "inode %llu drop %s RW lock\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno,
write ? "EXMODE" : "PRMODE");
if (!ocfs2_mount_local(osb))
ocfs2_cluster_unlock(OCFS2_SB(inode->i_sb), lockres, level);
mlog_exit_void();
}
/*
* ocfs2_open_lock always get PR mode lock.
*/
int ocfs2_open_lock(struct inode *inode)
{
int status = 0;
struct ocfs2_lock_res *lockres;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
BUG_ON(!inode);
mlog_entry_void();
mlog(0, "inode %llu take PRMODE open lock\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno);
if (ocfs2_mount_local(osb))
goto out;
lockres = &OCFS2_I(inode)->ip_open_lockres;
status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres,
DLM_LOCK_PR, 0, 0);
if (status < 0)
mlog_errno(status);
out:
mlog_exit(status);
return status;
}
int ocfs2_try_open_lock(struct inode *inode, int write)
{
int status = 0, level;
struct ocfs2_lock_res *lockres;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
BUG_ON(!inode);
mlog_entry_void();
mlog(0, "inode %llu try to take %s open lock\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno,
write ? "EXMODE" : "PRMODE");
if (ocfs2_mount_local(osb))
goto out;
lockres = &OCFS2_I(inode)->ip_open_lockres;
level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
/*
* The file system may already holding a PRMODE/EXMODE open lock.
* Since we pass DLM_LKF_NOQUEUE, the request won't block waiting on
* other nodes and the -EAGAIN will indicate to the caller that
* this inode is still in use.
*/
status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres,
level, DLM_LKF_NOQUEUE, 0);
out:
mlog_exit(status);
return status;
}
/*
* ocfs2_open_unlock unlock PR and EX mode open locks.
*/
void ocfs2_open_unlock(struct inode *inode)
{
struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_open_lockres;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
mlog_entry_void();
mlog(0, "inode %llu drop open lock\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno);
if (ocfs2_mount_local(osb))
goto out;
if(lockres->l_ro_holders)
ocfs2_cluster_unlock(OCFS2_SB(inode->i_sb), lockres,
DLM_LOCK_PR);
if(lockres->l_ex_holders)
ocfs2_cluster_unlock(OCFS2_SB(inode->i_sb), lockres,
DLM_LOCK_EX);
out:
mlog_exit_void();
}
static int ocfs2_flock_handle_signal(struct ocfs2_lock_res *lockres,
int level)
{
int ret;
struct ocfs2_super *osb = ocfs2_get_lockres_osb(lockres);
unsigned long flags;
struct ocfs2_mask_waiter mw;
ocfs2_init_mask_waiter(&mw);
retry_cancel:
spin_lock_irqsave(&lockres->l_lock, flags);
if (lockres->l_flags & OCFS2_LOCK_BUSY) {
ret = ocfs2_prepare_cancel_convert(osb, lockres);
if (ret) {
spin_unlock_irqrestore(&lockres->l_lock, flags);
ret = ocfs2_cancel_convert(osb, lockres);
if (ret < 0) {
mlog_errno(ret);
goto out;
}
goto retry_cancel;
}
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
spin_unlock_irqrestore(&lockres->l_lock, flags);
ocfs2_wait_for_mask(&mw);
goto retry_cancel;
}
ret = -ERESTARTSYS;
/*
* We may still have gotten the lock, in which case there's no
* point to restarting the syscall.
*/
if (lockres->l_level == level)
ret = 0;
mlog(0, "Cancel returning %d. flags: 0x%lx, level: %d, act: %d\n", ret,
lockres->l_flags, lockres->l_level, lockres->l_action);
spin_unlock_irqrestore(&lockres->l_lock, flags);
out:
return ret;
}
/*
* ocfs2_file_lock() and ocfs2_file_unlock() map to a single pair of
* flock() calls. The locking approach this requires is sufficiently
* different from all other cluster lock types that we implement a
* seperate path to the "low-level" dlm calls. In particular:
*
* - No optimization of lock levels is done - we take at exactly
* what's been requested.
*
* - No lock caching is employed. We immediately downconvert to
* no-lock at unlock time. This also means flock locks never go on
* the blocking list).
*
* - Since userspace can trivially deadlock itself with flock, we make
* sure to allow cancellation of a misbehaving applications flock()
* request.
*
* - Access to any flock lockres doesn't require concurrency, so we
* can simplify the code by requiring the caller to guarantee
* serialization of dlmglue flock calls.
*/
int ocfs2_file_lock(struct file *file, int ex, int trylock)
{
int ret, level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
unsigned int lkm_flags = trylock ? DLM_LKF_NOQUEUE : 0;
unsigned long flags;
struct ocfs2_file_private *fp = file->private_data;
struct ocfs2_lock_res *lockres = &fp->fp_flock;
struct ocfs2_super *osb = OCFS2_SB(file->f_mapping->host->i_sb);
struct ocfs2_mask_waiter mw;
ocfs2_init_mask_waiter(&mw);
if ((lockres->l_flags & OCFS2_LOCK_BUSY) ||
(lockres->l_level > DLM_LOCK_NL)) {
mlog(ML_ERROR,
"File lock \"%s\" has busy or locked state: flags: 0x%lx, "
"level: %u\n", lockres->l_name, lockres->l_flags,
lockres->l_level);
return -EINVAL;
}
spin_lock_irqsave(&lockres->l_lock, flags);
if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
spin_unlock_irqrestore(&lockres->l_lock, flags);
/*
* Get the lock at NLMODE to start - that way we
* can cancel the upconvert request if need be.
*/
ret = ocfs2_lock_create(osb, lockres, DLM_LOCK_NL, 0);
if (ret < 0) {
mlog_errno(ret);
goto out;
}
ret = ocfs2_wait_for_mask(&mw);
if (ret) {
mlog_errno(ret);
goto out;
}
spin_lock_irqsave(&lockres->l_lock, flags);
}
lockres->l_action = OCFS2_AST_CONVERT;
lkm_flags |= DLM_LKF_CONVERT;
lockres->l_requested = level;
lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
spin_unlock_irqrestore(&lockres->l_lock, flags);
ret = ocfs2_dlm_lock(osb->cconn, level, &lockres->l_lksb, lkm_flags,
lockres->l_name, OCFS2_LOCK_ID_MAX_LEN - 1,
lockres);
if (ret) {
if (!trylock || (ret != -EAGAIN)) {
ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
ret = -EINVAL;
}
ocfs2_recover_from_dlm_error(lockres, 1);
lockres_remove_mask_waiter(lockres, &mw);
goto out;
}
ret = ocfs2_wait_for_mask_interruptible(&mw, lockres);
if (ret == -ERESTARTSYS) {
/*
* Userspace can cause deadlock itself with
* flock(). Current behavior locally is to allow the
* deadlock, but abort the system call if a signal is
* received. We follow this example, otherwise a
* poorly written program could sit in kernel until
* reboot.
*
* Handling this is a bit more complicated for Ocfs2
* though. We can't exit this function with an
* outstanding lock request, so a cancel convert is
* required. We intentionally overwrite 'ret' - if the
* cancel fails and the lock was granted, it's easier
* to just bubble sucess back up to the user.
*/
ret = ocfs2_flock_handle_signal(lockres, level);
} else if (!ret && (level > lockres->l_level)) {
/* Trylock failed asynchronously */
BUG_ON(!trylock);
ret = -EAGAIN;
}
out:
mlog(0, "Lock: \"%s\" ex: %d, trylock: %d, returns: %d\n",
lockres->l_name, ex, trylock, ret);
return ret;
}
void ocfs2_file_unlock(struct file *file)
{
int ret;
unsigned int gen;
unsigned long flags;
struct ocfs2_file_private *fp = file->private_data;
struct ocfs2_lock_res *lockres = &fp->fp_flock;
struct ocfs2_super *osb = OCFS2_SB(file->f_mapping->host->i_sb);
struct ocfs2_mask_waiter mw;
ocfs2_init_mask_waiter(&mw);
if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED))
return;
if (lockres->l_level == DLM_LOCK_NL)
return;
mlog(0, "Unlock: \"%s\" flags: 0x%lx, level: %d, act: %d\n",
lockres->l_name, lockres->l_flags, lockres->l_level,
lockres->l_action);
spin_lock_irqsave(&lockres->l_lock, flags);
/*
* Fake a blocking ast for the downconvert code.
*/
lockres_or_flags(lockres, OCFS2_LOCK_BLOCKED);
lockres->l_blocking = DLM_LOCK_EX;
gen = ocfs2_prepare_downconvert(lockres, DLM_LOCK_NL);
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
spin_unlock_irqrestore(&lockres->l_lock, flags);
ret = ocfs2_downconvert_lock(osb, lockres, DLM_LOCK_NL, 0, gen);
if (ret) {
mlog_errno(ret);
return;
}
ret = ocfs2_wait_for_mask(&mw);
if (ret)
mlog_errno(ret);
}
static void ocfs2_downconvert_on_unlock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
int kick = 0;
mlog_entry_void();
/* If we know that another node is waiting on our lock, kick
* the downconvert thread * pre-emptively when we reach a release
* condition. */
if (lockres->l_flags & OCFS2_LOCK_BLOCKED) {
switch(lockres->l_blocking) {
case DLM_LOCK_EX:
if (!lockres->l_ex_holders && !lockres->l_ro_holders)
kick = 1;
break;
case DLM_LOCK_PR:
if (!lockres->l_ex_holders)
kick = 1;
break;
default:
BUG();
}
}
if (kick)
ocfs2_wake_downconvert_thread(osb);
mlog_exit_void();
}
#define OCFS2_SEC_BITS 34
#define OCFS2_SEC_SHIFT (64 - 34)
#define OCFS2_NSEC_MASK ((1ULL << OCFS2_SEC_SHIFT) - 1)
/* LVB only has room for 64 bits of time here so we pack it for
* now. */
static u64 ocfs2_pack_timespec(struct timespec *spec)
{
u64 res;
u64 sec = spec->tv_sec;
u32 nsec = spec->tv_nsec;
res = (sec << OCFS2_SEC_SHIFT) | (nsec & OCFS2_NSEC_MASK);
return res;
}
/* Call this with the lockres locked. I am reasonably sure we don't
* need ip_lock in this function as anyone who would be changing those
* values is supposed to be blocked in ocfs2_inode_lock right now. */
static void __ocfs2_stuff_meta_lvb(struct inode *inode)
{
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
struct ocfs2_meta_lvb *lvb;
mlog_entry_void();
lvb = (struct ocfs2_meta_lvb *)ocfs2_dlm_lvb(&lockres->l_lksb);
/*
* Invalidate the LVB of a deleted inode - this way other
* nodes are forced to go to disk and discover the new inode
* status.
*/
if (oi->ip_flags & OCFS2_INODE_DELETED) {
lvb->lvb_version = 0;
goto out;
}
lvb->lvb_version = OCFS2_LVB_VERSION;
lvb->lvb_isize = cpu_to_be64(i_size_read(inode));
lvb->lvb_iclusters = cpu_to_be32(oi->ip_clusters);
lvb->lvb_iuid = cpu_to_be32(inode->i_uid);
lvb->lvb_igid = cpu_to_be32(inode->i_gid);
lvb->lvb_imode = cpu_to_be16(inode->i_mode);
lvb->lvb_inlink = cpu_to_be16(inode->i_nlink);
lvb->lvb_iatime_packed =
cpu_to_be64(ocfs2_pack_timespec(&inode->i_atime));
lvb->lvb_ictime_packed =
cpu_to_be64(ocfs2_pack_timespec(&inode->i_ctime));
lvb->lvb_imtime_packed =
cpu_to_be64(ocfs2_pack_timespec(&inode->i_mtime));
lvb->lvb_iattr = cpu_to_be32(oi->ip_attr);
lvb->lvb_idynfeatures = cpu_to_be16(oi->ip_dyn_features);
lvb->lvb_igeneration = cpu_to_be32(inode->i_generation);
out:
mlog_meta_lvb(0, lockres);
mlog_exit_void();
}
static void ocfs2_unpack_timespec(struct timespec *spec,
u64 packed_time)
{
spec->tv_sec = packed_time >> OCFS2_SEC_SHIFT;
spec->tv_nsec = packed_time & OCFS2_NSEC_MASK;
}
static void ocfs2_refresh_inode_from_lvb(struct inode *inode)
{
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
struct ocfs2_meta_lvb *lvb;
mlog_entry_void();
mlog_meta_lvb(0, lockres);
lvb = (struct ocfs2_meta_lvb *)ocfs2_dlm_lvb(&lockres->l_lksb);
/* We're safe here without the lockres lock... */
spin_lock(&oi->ip_lock);
oi->ip_clusters = be32_to_cpu(lvb->lvb_iclusters);
i_size_write(inode, be64_to_cpu(lvb->lvb_isize));
oi->ip_attr = be32_to_cpu(lvb->lvb_iattr);
oi->ip_dyn_features = be16_to_cpu(lvb->lvb_idynfeatures);
ocfs2_set_inode_flags(inode);
/* fast-symlinks are a special case */
if (S_ISLNK(inode->i_mode) && !oi->ip_clusters)
inode->i_blocks = 0;
else
inode->i_blocks = ocfs2_inode_sector_count(inode);
inode->i_uid = be32_to_cpu(lvb->lvb_iuid);
inode->i_gid = be32_to_cpu(lvb->lvb_igid);
inode->i_mode = be16_to_cpu(lvb->lvb_imode);
inode->i_nlink = be16_to_cpu(lvb->lvb_inlink);
ocfs2_unpack_timespec(&inode->i_atime,
be64_to_cpu(lvb->lvb_iatime_packed));
ocfs2_unpack_timespec(&inode->i_mtime,
be64_to_cpu(lvb->lvb_imtime_packed));
ocfs2_unpack_timespec(&inode->i_ctime,
be64_to_cpu(lvb->lvb_ictime_packed));
spin_unlock(&oi->ip_lock);
mlog_exit_void();
}
static inline int ocfs2_meta_lvb_is_trustable(struct inode *inode,
struct ocfs2_lock_res *lockres)
{
struct ocfs2_meta_lvb *lvb =
(struct ocfs2_meta_lvb *)ocfs2_dlm_lvb(&lockres->l_lksb);
if (lvb->lvb_version == OCFS2_LVB_VERSION
&& be32_to_cpu(lvb->lvb_igeneration) == inode->i_generation)
return 1;
return 0;
}
/* Determine whether a lock resource needs to be refreshed, and
* arbitrate who gets to refresh it.
*
* 0 means no refresh needed.
*
* > 0 means you need to refresh this and you MUST call
* ocfs2_complete_lock_res_refresh afterwards. */
static int ocfs2_should_refresh_lock_res(struct ocfs2_lock_res *lockres)
{
unsigned long flags;
int status = 0;
mlog_entry_void();
refresh_check:
spin_lock_irqsave(&lockres->l_lock, flags);
if (!(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH)) {
spin_unlock_irqrestore(&lockres->l_lock, flags);
goto bail;
}
if (lockres->l_flags & OCFS2_LOCK_REFRESHING) {
spin_unlock_irqrestore(&lockres->l_lock, flags);
ocfs2_wait_on_refreshing_lock(lockres);
goto refresh_check;
}
/* Ok, I'll be the one to refresh this lock. */
lockres_or_flags(lockres, OCFS2_LOCK_REFRESHING);
spin_unlock_irqrestore(&lockres->l_lock, flags);
status = 1;
bail:
mlog_exit(status);
return status;
}
/* If status is non zero, I'll mark it as not being in refresh
* anymroe, but i won't clear the needs refresh flag. */
static inline void ocfs2_complete_lock_res_refresh(struct ocfs2_lock_res *lockres,
int status)
{
unsigned long flags;
mlog_entry_void();
spin_lock_irqsave(&lockres->l_lock, flags);
lockres_clear_flags(lockres, OCFS2_LOCK_REFRESHING);
if (!status)
lockres_clear_flags(lockres, OCFS2_LOCK_NEEDS_REFRESH);
spin_unlock_irqrestore(&lockres->l_lock, flags);
wake_up(&lockres->l_event);
mlog_exit_void();
}
/* may or may not return a bh if it went to disk. */
static int ocfs2_inode_lock_update(struct inode *inode,
struct buffer_head **bh)
{
int status = 0;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
struct ocfs2_dinode *fe;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
mlog_entry_void();
if (ocfs2_mount_local(osb))
goto bail;
spin_lock(&oi->ip_lock);
if (oi->ip_flags & OCFS2_INODE_DELETED) {
mlog(0, "Orphaned inode %llu was deleted while we "
"were waiting on a lock. ip_flags = 0x%x\n",
(unsigned long long)oi->ip_blkno, oi->ip_flags);
spin_unlock(&oi->ip_lock);
status = -ENOENT;
goto bail;
}
spin_unlock(&oi->ip_lock);
if (!ocfs2_should_refresh_lock_res(lockres))
goto bail;
/* This will discard any caching information we might have had
* for the inode metadata. */
ocfs2_metadata_cache_purge(inode);
ocfs2_extent_map_trunc(inode, 0);
if (ocfs2_meta_lvb_is_trustable(inode, lockres)) {
mlog(0, "Trusting LVB on inode %llu\n",
(unsigned long long)oi->ip_blkno);
ocfs2_refresh_inode_from_lvb(inode);
} else {
/* Boo, we have to go to disk. */
/* read bh, cast, ocfs2_refresh_inode */
status = ocfs2_read_block(inode, oi->ip_blkno, bh);
if (status < 0) {
mlog_errno(status);
goto bail_refresh;
}
fe = (struct ocfs2_dinode *) (*bh)->b_data;
/* This is a good chance to make sure we're not
* locking an invalid object.
*
* We bug on a stale inode here because we checked
* above whether it was wiped from disk. The wiping
* node provides a guarantee that we receive that
* message and can mark the inode before dropping any
* locks associated with it. */
if (!OCFS2_IS_VALID_DINODE(fe)) {
OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
status = -EIO;
goto bail_refresh;
}
mlog_bug_on_msg(inode->i_generation !=
le32_to_cpu(fe->i_generation),
"Invalid dinode %llu disk generation: %u "
"inode->i_generation: %u\n",
(unsigned long long)oi->ip_blkno,
le32_to_cpu(fe->i_generation),
inode->i_generation);
mlog_bug_on_msg(le64_to_cpu(fe->i_dtime) ||
!(fe->i_flags & cpu_to_le32(OCFS2_VALID_FL)),
"Stale dinode %llu dtime: %llu flags: 0x%x\n",
(unsigned long long)oi->ip_blkno,
(unsigned long long)le64_to_cpu(fe->i_dtime),
le32_to_cpu(fe->i_flags));
ocfs2_refresh_inode(inode, fe);
ocfs2_track_lock_refresh(lockres);
}
status = 0;
bail_refresh:
ocfs2_complete_lock_res_refresh(lockres, status);
bail:
mlog_exit(status);
return status;
}
static int ocfs2_assign_bh(struct inode *inode,
struct buffer_head **ret_bh,
struct buffer_head *passed_bh)
{
int status;
if (passed_bh) {
/* Ok, the update went to disk for us, use the
* returned bh. */
*ret_bh = passed_bh;
get_bh(*ret_bh);
return 0;
}
status = ocfs2_read_block(inode, OCFS2_I(inode)->ip_blkno, ret_bh);
if (status < 0)
mlog_errno(status);
return status;
}
/*
* returns < 0 error if the callback will never be called, otherwise
* the result of the lock will be communicated via the callback.
*/
int ocfs2_inode_lock_full(struct inode *inode,
struct buffer_head **ret_bh,
int ex,
int arg_flags)
{
int status, level, acquired;
u32 dlm_flags;
struct ocfs2_lock_res *lockres = NULL;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
struct buffer_head *local_bh = NULL;
BUG_ON(!inode);
mlog_entry_void();
mlog(0, "inode %llu, take %s META lock\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno,
ex ? "EXMODE" : "PRMODE");
status = 0;
acquired = 0;
/* We'll allow faking a readonly metadata lock for
* rodevices. */
if (ocfs2_is_hard_readonly(osb)) {
if (ex)
status = -EROFS;
goto bail;
}
if (ocfs2_mount_local(osb))
goto local;
if (!(arg_flags & OCFS2_META_LOCK_RECOVERY))
ocfs2_wait_for_recovery(osb);
lockres = &OCFS2_I(inode)->ip_inode_lockres;
level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
dlm_flags = 0;
if (arg_flags & OCFS2_META_LOCK_NOQUEUE)
dlm_flags |= DLM_LKF_NOQUEUE;
status = ocfs2_cluster_lock(osb, lockres, level, dlm_flags, arg_flags);
if (status < 0) {
if (status != -EAGAIN && status != -EIOCBRETRY)
mlog_errno(status);
goto bail;
}
/* Notify the error cleanup path to drop the cluster lock. */
acquired = 1;
/* We wait twice because a node may have died while we were in
* the lower dlm layers. The second time though, we've
* committed to owning this lock so we don't allow signals to
* abort the operation. */
if (!(arg_flags & OCFS2_META_LOCK_RECOVERY))
ocfs2_wait_for_recovery(osb);
local:
/*
* We only see this flag if we're being called from
* ocfs2_read_locked_inode(). It means we're locking an inode
* which hasn't been populated yet, so clear the refresh flag
* and let the caller handle it.
*/
if (inode->i_state & I_NEW) {
status = 0;
if (lockres)
ocfs2_complete_lock_res_refresh(lockres, 0);
goto bail;
}
/* This is fun. The caller may want a bh back, or it may
* not. ocfs2_inode_lock_update definitely wants one in, but
* may or may not read one, depending on what's in the
* LVB. The result of all of this is that we've *only* gone to
* disk if we have to, so the complexity is worthwhile. */
status = ocfs2_inode_lock_update(inode, &local_bh);
if (status < 0) {
if (status != -ENOENT)
mlog_errno(status);
goto bail;
}
if (ret_bh) {
status = ocfs2_assign_bh(inode, ret_bh, local_bh);
if (status < 0) {
mlog_errno(status);
goto bail;
}
}
bail:
if (status < 0) {
if (ret_bh && (*ret_bh)) {
brelse(*ret_bh);
*ret_bh = NULL;
}
if (acquired)
ocfs2_inode_unlock(inode, ex);
}
if (local_bh)
brelse(local_bh);
mlog_exit(status);
return status;
}
/*
* This is working around a lock inversion between tasks acquiring DLM
* locks while holding a page lock and the downconvert thread which
* blocks dlm lock acquiry while acquiring page locks.
*
* ** These _with_page variantes are only intended to be called from aop
* methods that hold page locks and return a very specific *positive* error
* code that aop methods pass up to the VFS -- test for errors with != 0. **
*
* The DLM is called such that it returns -EAGAIN if it would have
* blocked waiting for the downconvert thread. In that case we unlock
* our page so the downconvert thread can make progress. Once we've
* done this we have to return AOP_TRUNCATED_PAGE so the aop method
* that called us can bubble that back up into the VFS who will then
* immediately retry the aop call.
*
* We do a blocking lock and immediate unlock before returning, though, so that
* the lock has a great chance of being cached on this node by the time the VFS
* calls back to retry the aop. This has a potential to livelock as nodes
* ping locks back and forth, but that's a risk we're willing to take to avoid
* the lock inversion simply.
*/
int ocfs2_inode_lock_with_page(struct inode *inode,
struct buffer_head **ret_bh,
int ex,
struct page *page)
{
int ret;
ret = ocfs2_inode_lock_full(inode, ret_bh, ex, OCFS2_LOCK_NONBLOCK);
if (ret == -EAGAIN) {
unlock_page(page);
if (ocfs2_inode_lock(inode, ret_bh, ex) == 0)
ocfs2_inode_unlock(inode, ex);
ret = AOP_TRUNCATED_PAGE;
}
return ret;
}
int ocfs2_inode_lock_atime(struct inode *inode,
struct vfsmount *vfsmnt,
int *level)
{
int ret;
mlog_entry_void();
ret = ocfs2_inode_lock(inode, NULL, 0);
if (ret < 0) {
mlog_errno(ret);
return ret;
}
/*
* If we should update atime, we will get EX lock,
* otherwise we just get PR lock.
*/
if (ocfs2_should_update_atime(inode, vfsmnt)) {
struct buffer_head *bh = NULL;
ocfs2_inode_unlock(inode, 0);
ret = ocfs2_inode_lock(inode, &bh, 1);
if (ret < 0) {
mlog_errno(ret);
return ret;
}
*level = 1;
if (ocfs2_should_update_atime(inode, vfsmnt))
ocfs2_update_inode_atime(inode, bh);
if (bh)
brelse(bh);
} else
*level = 0;
mlog_exit(ret);
return ret;
}
void ocfs2_inode_unlock(struct inode *inode,
int ex)
{
int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
struct ocfs2_lock_res *lockres = &OCFS2_I(inode)->ip_inode_lockres;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
mlog_entry_void();
mlog(0, "inode %llu drop %s META lock\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno,
ex ? "EXMODE" : "PRMODE");
if (!ocfs2_is_hard_readonly(OCFS2_SB(inode->i_sb)) &&
!ocfs2_mount_local(osb))
ocfs2_cluster_unlock(OCFS2_SB(inode->i_sb), lockres, level);
mlog_exit_void();
}
int ocfs2_super_lock(struct ocfs2_super *osb,
int ex)
{
int status = 0;
int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
struct ocfs2_lock_res *lockres = &osb->osb_super_lockres;
mlog_entry_void();
if (ocfs2_is_hard_readonly(osb))
return -EROFS;
if (ocfs2_mount_local(osb))
goto bail;
status = ocfs2_cluster_lock(osb, lockres, level, 0, 0);
if (status < 0) {
mlog_errno(status);
goto bail;
}
/* The super block lock path is really in the best position to
* know when resources covered by the lock need to be
* refreshed, so we do it here. Of course, making sense of
* everything is up to the caller :) */
status = ocfs2_should_refresh_lock_res(lockres);
if (status < 0) {
mlog_errno(status);
goto bail;
}
if (status) {
status = ocfs2_refresh_slot_info(osb);
ocfs2_complete_lock_res_refresh(lockres, status);
if (status < 0)
mlog_errno(status);
ocfs2_track_lock_refresh(lockres);
}
bail:
mlog_exit(status);
return status;
}
void ocfs2_super_unlock(struct ocfs2_super *osb,
int ex)
{
int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
struct ocfs2_lock_res *lockres = &osb->osb_super_lockres;
if (!ocfs2_mount_local(osb))
ocfs2_cluster_unlock(osb, lockres, level);
}
int ocfs2_rename_lock(struct ocfs2_super *osb)
{
int status;
struct ocfs2_lock_res *lockres = &osb->osb_rename_lockres;
if (ocfs2_is_hard_readonly(osb))
return -EROFS;
if (ocfs2_mount_local(osb))
return 0;
status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX, 0, 0);
if (status < 0)
mlog_errno(status);
return status;
}
void ocfs2_rename_unlock(struct ocfs2_super *osb)
{
struct ocfs2_lock_res *lockres = &osb->osb_rename_lockres;
if (!ocfs2_mount_local(osb))
ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
}
int ocfs2_dentry_lock(struct dentry *dentry, int ex)
{
int ret;
int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
BUG_ON(!dl);
if (ocfs2_is_hard_readonly(osb))
return -EROFS;
if (ocfs2_mount_local(osb))
return 0;
ret = ocfs2_cluster_lock(osb, &dl->dl_lockres, level, 0, 0);
if (ret < 0)
mlog_errno(ret);
return ret;
}
void ocfs2_dentry_unlock(struct dentry *dentry, int ex)
{
int level = ex ? DLM_LOCK_EX : DLM_LOCK_PR;
struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
if (!ocfs2_mount_local(osb))
ocfs2_cluster_unlock(osb, &dl->dl_lockres, level);
}
/* Reference counting of the dlm debug structure. We want this because
* open references on the debug inodes can live on after a mount, so
* we can't rely on the ocfs2_super to always exist. */
static void ocfs2_dlm_debug_free(struct kref *kref)
{
struct ocfs2_dlm_debug *dlm_debug;
dlm_debug = container_of(kref, struct ocfs2_dlm_debug, d_refcnt);
kfree(dlm_debug);
}
void ocfs2_put_dlm_debug(struct ocfs2_dlm_debug *dlm_debug)
{
if (dlm_debug)
kref_put(&dlm_debug->d_refcnt, ocfs2_dlm_debug_free);
}
static void ocfs2_get_dlm_debug(struct ocfs2_dlm_debug *debug)
{
kref_get(&debug->d_refcnt);
}
struct ocfs2_dlm_debug *ocfs2_new_dlm_debug(void)
{
struct ocfs2_dlm_debug *dlm_debug;
dlm_debug = kmalloc(sizeof(struct ocfs2_dlm_debug), GFP_KERNEL);
if (!dlm_debug) {
mlog_errno(-ENOMEM);
goto out;
}
kref_init(&dlm_debug->d_refcnt);
INIT_LIST_HEAD(&dlm_debug->d_lockres_tracking);
dlm_debug->d_locking_state = NULL;
out:
return dlm_debug;
}
/* Access to this is arbitrated for us via seq_file->sem. */
struct ocfs2_dlm_seq_priv {
struct ocfs2_dlm_debug *p_dlm_debug;
struct ocfs2_lock_res p_iter_res;
struct ocfs2_lock_res p_tmp_res;
};
static struct ocfs2_lock_res *ocfs2_dlm_next_res(struct ocfs2_lock_res *start,
struct ocfs2_dlm_seq_priv *priv)
{
struct ocfs2_lock_res *iter, *ret = NULL;
struct ocfs2_dlm_debug *dlm_debug = priv->p_dlm_debug;
assert_spin_locked(&ocfs2_dlm_tracking_lock);
list_for_each_entry(iter, &start->l_debug_list, l_debug_list) {
/* discover the head of the list */
if (&iter->l_debug_list == &dlm_debug->d_lockres_tracking) {
mlog(0, "End of list found, %p\n", ret);
break;
}
/* We track our "dummy" iteration lockres' by a NULL
* l_ops field. */
if (iter->l_ops != NULL) {
ret = iter;
break;
}
}
return ret;
}
static void *ocfs2_dlm_seq_start(struct seq_file *m, loff_t *pos)
{
struct ocfs2_dlm_seq_priv *priv = m->private;
struct ocfs2_lock_res *iter;
spin_lock(&ocfs2_dlm_tracking_lock);
iter = ocfs2_dlm_next_res(&priv->p_iter_res, priv);
if (iter) {
/* Since lockres' have the lifetime of their container
* (which can be inodes, ocfs2_supers, etc) we want to
* copy this out to a temporary lockres while still
* under the spinlock. Obviously after this we can't
* trust any pointers on the copy returned, but that's
* ok as the information we want isn't typically held
* in them. */
priv->p_tmp_res = *iter;
iter = &priv->p_tmp_res;
}
spin_unlock(&ocfs2_dlm_tracking_lock);
return iter;
}
static void ocfs2_dlm_seq_stop(struct seq_file *m, void *v)
{
}
static void *ocfs2_dlm_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ocfs2_dlm_seq_priv *priv = m->private;
struct ocfs2_lock_res *iter = v;
struct ocfs2_lock_res *dummy = &priv->p_iter_res;
spin_lock(&ocfs2_dlm_tracking_lock);
iter = ocfs2_dlm_next_res(iter, priv);
list_del_init(&dummy->l_debug_list);
if (iter) {
list_add(&dummy->l_debug_list, &iter->l_debug_list);
priv->p_tmp_res = *iter;
iter = &priv->p_tmp_res;
}
spin_unlock(&ocfs2_dlm_tracking_lock);
return iter;
}
/* So that debugfs.ocfs2 can determine which format is being used */
#define OCFS2_DLM_DEBUG_STR_VERSION 2
static int ocfs2_dlm_seq_show(struct seq_file *m, void *v)
{
int i;
char *lvb;
struct ocfs2_lock_res *lockres = v;
if (!lockres)
return -EINVAL;
seq_printf(m, "0x%x\t", OCFS2_DLM_DEBUG_STR_VERSION);
if (lockres->l_type == OCFS2_LOCK_TYPE_DENTRY)
seq_printf(m, "%.*s%08x\t", OCFS2_DENTRY_LOCK_INO_START - 1,
lockres->l_name,
(unsigned int)ocfs2_get_dentry_lock_ino(lockres));
else
seq_printf(m, "%.*s\t", OCFS2_LOCK_ID_MAX_LEN, lockres->l_name);
seq_printf(m, "%d\t"
"0x%lx\t"
"0x%x\t"
"0x%x\t"
"%u\t"
"%u\t"
"%d\t"
"%d\t",
lockres->l_level,
lockres->l_flags,
lockres->l_action,
lockres->l_unlock_action,
lockres->l_ro_holders,
lockres->l_ex_holders,
lockres->l_requested,
lockres->l_blocking);
/* Dump the raw LVB */
lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
for(i = 0; i < DLM_LVB_LEN; i++)
seq_printf(m, "0x%x\t", lvb[i]);
#ifdef CONFIG_OCFS2_FS_STATS
# define lock_num_prmode(_l) (_l)->l_lock_num_prmode
# define lock_num_exmode(_l) (_l)->l_lock_num_exmode
# define lock_num_prmode_failed(_l) (_l)->l_lock_num_prmode_failed
# define lock_num_exmode_failed(_l) (_l)->l_lock_num_exmode_failed
# define lock_total_prmode(_l) (_l)->l_lock_total_prmode
# define lock_total_exmode(_l) (_l)->l_lock_total_exmode
# define lock_max_prmode(_l) (_l)->l_lock_max_prmode
# define lock_max_exmode(_l) (_l)->l_lock_max_exmode
# define lock_refresh(_l) (_l)->l_lock_refresh
#else
# define lock_num_prmode(_l) (0ULL)
# define lock_num_exmode(_l) (0ULL)
# define lock_num_prmode_failed(_l) (0)
# define lock_num_exmode_failed(_l) (0)
# define lock_total_prmode(_l) (0ULL)
# define lock_total_exmode(_l) (0ULL)
# define lock_max_prmode(_l) (0)
# define lock_max_exmode(_l) (0)
# define lock_refresh(_l) (0)
#endif
/* The following seq_print was added in version 2 of this output */
seq_printf(m, "%llu\t"
"%llu\t"
"%u\t"
"%u\t"
"%llu\t"
"%llu\t"
"%u\t"
"%u\t"
"%u\t",
lock_num_prmode(lockres),
lock_num_exmode(lockres),
lock_num_prmode_failed(lockres),
lock_num_exmode_failed(lockres),
lock_total_prmode(lockres),
lock_total_exmode(lockres),
lock_max_prmode(lockres),
lock_max_exmode(lockres),
lock_refresh(lockres));
/* End the line */
seq_printf(m, "\n");
return 0;
}
static const struct seq_operations ocfs2_dlm_seq_ops = {
.start = ocfs2_dlm_seq_start,
.stop = ocfs2_dlm_seq_stop,
.next = ocfs2_dlm_seq_next,
.show = ocfs2_dlm_seq_show,
};
static int ocfs2_dlm_debug_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = (struct seq_file *) file->private_data;
struct ocfs2_dlm_seq_priv *priv = seq->private;
struct ocfs2_lock_res *res = &priv->p_iter_res;
ocfs2_remove_lockres_tracking(res);
ocfs2_put_dlm_debug(priv->p_dlm_debug);
return seq_release_private(inode, file);
}
static int ocfs2_dlm_debug_open(struct inode *inode, struct file *file)
{
int ret;
struct ocfs2_dlm_seq_priv *priv;
struct seq_file *seq;
struct ocfs2_super *osb;
priv = kzalloc(sizeof(struct ocfs2_dlm_seq_priv), GFP_KERNEL);
if (!priv) {
ret = -ENOMEM;
mlog_errno(ret);
goto out;
}
osb = inode->i_private;
ocfs2_get_dlm_debug(osb->osb_dlm_debug);
priv->p_dlm_debug = osb->osb_dlm_debug;
INIT_LIST_HEAD(&priv->p_iter_res.l_debug_list);
ret = seq_open(file, &ocfs2_dlm_seq_ops);
if (ret) {
kfree(priv);
mlog_errno(ret);
goto out;
}
seq = (struct seq_file *) file->private_data;
seq->private = priv;
ocfs2_add_lockres_tracking(&priv->p_iter_res,
priv->p_dlm_debug);
out:
return ret;
}
static const struct file_operations ocfs2_dlm_debug_fops = {
.open = ocfs2_dlm_debug_open,
.release = ocfs2_dlm_debug_release,
.read = seq_read,
.llseek = seq_lseek,
};
static int ocfs2_dlm_init_debug(struct ocfs2_super *osb)
{
int ret = 0;
struct ocfs2_dlm_debug *dlm_debug = osb->osb_dlm_debug;
dlm_debug->d_locking_state = debugfs_create_file("locking_state",
S_IFREG|S_IRUSR,
osb->osb_debug_root,
osb,
&ocfs2_dlm_debug_fops);
if (!dlm_debug->d_locking_state) {
ret = -EINVAL;
mlog(ML_ERROR,
"Unable to create locking state debugfs file.\n");
goto out;
}
ocfs2_get_dlm_debug(dlm_debug);
out:
return ret;
}
static void ocfs2_dlm_shutdown_debug(struct ocfs2_super *osb)
{
struct ocfs2_dlm_debug *dlm_debug = osb->osb_dlm_debug;
if (dlm_debug) {
debugfs_remove(dlm_debug->d_locking_state);
ocfs2_put_dlm_debug(dlm_debug);
}
}
int ocfs2_dlm_init(struct ocfs2_super *osb)
{
int status = 0;
struct ocfs2_cluster_connection *conn = NULL;
mlog_entry_void();
if (ocfs2_mount_local(osb)) {
osb->node_num = 0;
goto local;
}
status = ocfs2_dlm_init_debug(osb);
if (status < 0) {
mlog_errno(status);
goto bail;
}
/* launch downconvert thread */
osb->dc_task = kthread_run(ocfs2_downconvert_thread, osb, "ocfs2dc");
if (IS_ERR(osb->dc_task)) {
status = PTR_ERR(osb->dc_task);
osb->dc_task = NULL;
mlog_errno(status);
goto bail;
}
/* for now, uuid == domain */
status = ocfs2_cluster_connect(osb->osb_cluster_stack,
osb->uuid_str,
strlen(osb->uuid_str),
ocfs2_do_node_down, osb,
&conn);
if (status) {
mlog_errno(status);
goto bail;
}
status = ocfs2_cluster_this_node(&osb->node_num);
if (status < 0) {
mlog_errno(status);
mlog(ML_ERROR,
"could not find this host's node number\n");
ocfs2_cluster_disconnect(conn, 0);
goto bail;
}
local:
ocfs2_super_lock_res_init(&osb->osb_super_lockres, osb);
ocfs2_rename_lock_res_init(&osb->osb_rename_lockres, osb);
osb->cconn = conn;
status = 0;
bail:
if (status < 0) {
ocfs2_dlm_shutdown_debug(osb);
if (osb->dc_task)
kthread_stop(osb->dc_task);
}
mlog_exit(status);
return status;
}
void ocfs2_dlm_shutdown(struct ocfs2_super *osb,
int hangup_pending)
{
mlog_entry_void();
ocfs2_drop_osb_locks(osb);
/*
* Now that we have dropped all locks and ocfs2_dismount_volume()
* has disabled recovery, the DLM won't be talking to us. It's
* safe to tear things down before disconnecting the cluster.
*/
if (osb->dc_task) {
kthread_stop(osb->dc_task);
osb->dc_task = NULL;
}
ocfs2_lock_res_free(&osb->osb_super_lockres);
ocfs2_lock_res_free(&osb->osb_rename_lockres);
ocfs2_cluster_disconnect(osb->cconn, hangup_pending);
osb->cconn = NULL;
ocfs2_dlm_shutdown_debug(osb);
mlog_exit_void();
}
static void ocfs2_unlock_ast(void *opaque, int error)
{
struct ocfs2_lock_res *lockres = opaque;
unsigned long flags;
mlog_entry_void();
mlog(0, "UNLOCK AST called on lock %s, action = %d\n", lockres->l_name,
lockres->l_unlock_action);
spin_lock_irqsave(&lockres->l_lock, flags);
if (error) {
mlog(ML_ERROR, "Dlm passes error %d for lock %s, "
"unlock_action %d\n", error, lockres->l_name,
lockres->l_unlock_action);
spin_unlock_irqrestore(&lockres->l_lock, flags);
return;
}
switch(lockres->l_unlock_action) {
case OCFS2_UNLOCK_CANCEL_CONVERT:
mlog(0, "Cancel convert success for %s\n", lockres->l_name);
lockres->l_action = OCFS2_AST_INVALID;
break;
case OCFS2_UNLOCK_DROP_LOCK:
lockres->l_level = DLM_LOCK_IV;
break;
default:
BUG();
}
lockres_clear_flags(lockres, OCFS2_LOCK_BUSY);
lockres->l_unlock_action = OCFS2_UNLOCK_INVALID;
spin_unlock_irqrestore(&lockres->l_lock, flags);
wake_up(&lockres->l_event);
mlog_exit_void();
}
static int ocfs2_drop_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
int ret;
unsigned long flags;
u32 lkm_flags = 0;
/* We didn't get anywhere near actually using this lockres. */
if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED))
goto out;
if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB)
lkm_flags |= DLM_LKF_VALBLK;
spin_lock_irqsave(&lockres->l_lock, flags);
mlog_bug_on_msg(!(lockres->l_flags & OCFS2_LOCK_FREEING),
"lockres %s, flags 0x%lx\n",
lockres->l_name, lockres->l_flags);
while (lockres->l_flags & OCFS2_LOCK_BUSY) {
mlog(0, "waiting on busy lock \"%s\": flags = %lx, action = "
"%u, unlock_action = %u\n",
lockres->l_name, lockres->l_flags, lockres->l_action,
lockres->l_unlock_action);
spin_unlock_irqrestore(&lockres->l_lock, flags);
/* XXX: Today we just wait on any busy
* locks... Perhaps we need to cancel converts in the
* future? */
ocfs2_wait_on_busy_lock(lockres);
spin_lock_irqsave(&lockres->l_lock, flags);
}
if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
lockres->l_level == DLM_LOCK_EX &&
!(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
lockres->l_ops->set_lvb(lockres);
}
if (lockres->l_flags & OCFS2_LOCK_BUSY)
mlog(ML_ERROR, "destroying busy lock: \"%s\"\n",
lockres->l_name);
if (lockres->l_flags & OCFS2_LOCK_BLOCKED)
mlog(0, "destroying blocked lock: \"%s\"\n", lockres->l_name);
if (!(lockres->l_flags & OCFS2_LOCK_ATTACHED)) {
spin_unlock_irqrestore(&lockres->l_lock, flags);
goto out;
}
lockres_clear_flags(lockres, OCFS2_LOCK_ATTACHED);
/* make sure we never get here while waiting for an ast to
* fire. */
BUG_ON(lockres->l_action != OCFS2_AST_INVALID);
/* is this necessary? */
lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
lockres->l_unlock_action = OCFS2_UNLOCK_DROP_LOCK;
spin_unlock_irqrestore(&lockres->l_lock, flags);
mlog(0, "lock %s\n", lockres->l_name);
ret = ocfs2_dlm_unlock(osb->cconn, &lockres->l_lksb, lkm_flags,
lockres);
if (ret) {
ocfs2_log_dlm_error("ocfs2_dlm_unlock", ret, lockres);
mlog(ML_ERROR, "lockres flags: %lu\n", lockres->l_flags);
ocfs2_dlm_dump_lksb(&lockres->l_lksb);
BUG();
}
mlog(0, "lock %s, successfull return from ocfs2_dlm_unlock\n",
lockres->l_name);
ocfs2_wait_on_busy_lock(lockres);
out:
mlog_exit(0);
return 0;
}
/* Mark the lockres as being dropped. It will no longer be
* queued if blocking, but we still may have to wait on it
* being dequeued from the downconvert thread before we can consider
* it safe to drop.
*
* You can *not* attempt to call cluster_lock on this lockres anymore. */
void ocfs2_mark_lockres_freeing(struct ocfs2_lock_res *lockres)
{
int status;
struct ocfs2_mask_waiter mw;
unsigned long flags;
ocfs2_init_mask_waiter(&mw);
spin_lock_irqsave(&lockres->l_lock, flags);
lockres->l_flags |= OCFS2_LOCK_FREEING;
while (lockres->l_flags & OCFS2_LOCK_QUEUED) {
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_QUEUED, 0);
spin_unlock_irqrestore(&lockres->l_lock, flags);
mlog(0, "Waiting on lockres %s\n", lockres->l_name);
status = ocfs2_wait_for_mask(&mw);
if (status)
mlog_errno(status);
spin_lock_irqsave(&lockres->l_lock, flags);
}
spin_unlock_irqrestore(&lockres->l_lock, flags);
}
void ocfs2_simple_drop_lockres(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
int ret;
ocfs2_mark_lockres_freeing(lockres);
ret = ocfs2_drop_lock(osb, lockres);
if (ret)
mlog_errno(ret);
}
static void ocfs2_drop_osb_locks(struct ocfs2_super *osb)
{
ocfs2_simple_drop_lockres(osb, &osb->osb_super_lockres);
ocfs2_simple_drop_lockres(osb, &osb->osb_rename_lockres);
}
int ocfs2_drop_inode_locks(struct inode *inode)
{
int status, err;
mlog_entry_void();
/* No need to call ocfs2_mark_lockres_freeing here -
* ocfs2_clear_inode has done it for us. */
err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
&OCFS2_I(inode)->ip_open_lockres);
if (err < 0)
mlog_errno(err);
status = err;
err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
&OCFS2_I(inode)->ip_inode_lockres);
if (err < 0)
mlog_errno(err);
if (err < 0 && !status)
status = err;
err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
&OCFS2_I(inode)->ip_rw_lockres);
if (err < 0)
mlog_errno(err);
if (err < 0 && !status)
status = err;
mlog_exit(status);
return status;
}
static unsigned int ocfs2_prepare_downconvert(struct ocfs2_lock_res *lockres,
int new_level)
{
assert_spin_locked(&lockres->l_lock);
BUG_ON(lockres->l_blocking <= DLM_LOCK_NL);
if (lockres->l_level <= new_level) {
mlog(ML_ERROR, "lockres->l_level (%d) <= new_level (%d)\n",
lockres->l_level, new_level);
BUG();
}
mlog(0, "lock %s, new_level = %d, l_blocking = %d\n",
lockres->l_name, new_level, lockres->l_blocking);
lockres->l_action = OCFS2_AST_DOWNCONVERT;
lockres->l_requested = new_level;
lockres_or_flags(lockres, OCFS2_LOCK_BUSY);
return lockres_set_pending(lockres);
}
static int ocfs2_downconvert_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
int new_level,
int lvb,
unsigned int generation)
{
int ret;
u32 dlm_flags = DLM_LKF_CONVERT;
mlog_entry_void();
if (lvb)
dlm_flags |= DLM_LKF_VALBLK;
ret = ocfs2_dlm_lock(osb->cconn,
new_level,
&lockres->l_lksb,
dlm_flags,
lockres->l_name,
OCFS2_LOCK_ID_MAX_LEN - 1,
lockres);
lockres_clear_pending(lockres, generation, osb);
if (ret) {
ocfs2_log_dlm_error("ocfs2_dlm_lock", ret, lockres);
ocfs2_recover_from_dlm_error(lockres, 1);
goto bail;
}
ret = 0;
bail:
mlog_exit(ret);
return ret;
}
/* returns 1 when the caller should unlock and call ocfs2_dlm_unlock */
static int ocfs2_prepare_cancel_convert(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
assert_spin_locked(&lockres->l_lock);
mlog_entry_void();
mlog(0, "lock %s\n", lockres->l_name);
if (lockres->l_unlock_action == OCFS2_UNLOCK_CANCEL_CONVERT) {
/* If we're already trying to cancel a lock conversion
* then just drop the spinlock and allow the caller to
* requeue this lock. */
mlog(0, "Lockres %s, skip convert\n", lockres->l_name);
return 0;
}
/* were we in a convert when we got the bast fire? */
BUG_ON(lockres->l_action != OCFS2_AST_CONVERT &&
lockres->l_action != OCFS2_AST_DOWNCONVERT);
/* set things up for the unlockast to know to just
* clear out the ast_action and unset busy, etc. */
lockres->l_unlock_action = OCFS2_UNLOCK_CANCEL_CONVERT;
mlog_bug_on_msg(!(lockres->l_flags & OCFS2_LOCK_BUSY),
"lock %s, invalid flags: 0x%lx\n",
lockres->l_name, lockres->l_flags);
return 1;
}
static int ocfs2_cancel_convert(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
int ret;
mlog_entry_void();
mlog(0, "lock %s\n", lockres->l_name);
ret = ocfs2_dlm_unlock(osb->cconn, &lockres->l_lksb,
DLM_LKF_CANCEL, lockres);
if (ret) {
ocfs2_log_dlm_error("ocfs2_dlm_unlock", ret, lockres);
ocfs2_recover_from_dlm_error(lockres, 0);
}
mlog(0, "lock %s return from ocfs2_dlm_unlock\n", lockres->l_name);
mlog_exit(ret);
return ret;
}
static int ocfs2_unblock_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
struct ocfs2_unblock_ctl *ctl)
{
unsigned long flags;
int blocking;
int new_level;
int ret = 0;
int set_lvb = 0;
unsigned int gen;
mlog_entry_void();
spin_lock_irqsave(&lockres->l_lock, flags);
BUG_ON(!(lockres->l_flags & OCFS2_LOCK_BLOCKED));
recheck:
if (lockres->l_flags & OCFS2_LOCK_BUSY) {
/* XXX
* This is a *big* race. The OCFS2_LOCK_PENDING flag
* exists entirely for one reason - another thread has set
* OCFS2_LOCK_BUSY, but has *NOT* yet called dlm_lock().
*
* If we do ocfs2_cancel_convert() before the other thread
* calls dlm_lock(), our cancel will do nothing. We will
* get no ast, and we will have no way of knowing the
* cancel failed. Meanwhile, the other thread will call
* into dlm_lock() and wait...forever.
*
* Why forever? Because another node has asked for the
* lock first; that's why we're here in unblock_lock().
*
* The solution is OCFS2_LOCK_PENDING. When PENDING is
* set, we just requeue the unblock. Only when the other
* thread has called dlm_lock() and cleared PENDING will
* we then cancel their request.
*
* All callers of dlm_lock() must set OCFS2_DLM_PENDING
* at the same time they set OCFS2_DLM_BUSY. They must
* clear OCFS2_DLM_PENDING after dlm_lock() returns.
*/
if (lockres->l_flags & OCFS2_LOCK_PENDING)
goto leave_requeue;
ctl->requeue = 1;
ret = ocfs2_prepare_cancel_convert(osb, lockres);
spin_unlock_irqrestore(&lockres->l_lock, flags);
if (ret) {
ret = ocfs2_cancel_convert(osb, lockres);
if (ret < 0)
mlog_errno(ret);
}
goto leave;
}
/* if we're blocking an exclusive and we have *any* holders,
* then requeue. */
if ((lockres->l_blocking == DLM_LOCK_EX)
&& (lockres->l_ex_holders || lockres->l_ro_holders))
goto leave_requeue;
/* If it's a PR we're blocking, then only
* requeue if we've got any EX holders */
if (lockres->l_blocking == DLM_LOCK_PR &&
lockres->l_ex_holders)
goto leave_requeue;
/*
* Can we get a lock in this state if the holder counts are
* zero? The meta data unblock code used to check this.
*/
if ((lockres->l_ops->flags & LOCK_TYPE_REQUIRES_REFRESH)
&& (lockres->l_flags & OCFS2_LOCK_REFRESHING))
goto leave_requeue;
new_level = ocfs2_highest_compat_lock_level(lockres->l_blocking);
if (lockres->l_ops->check_downconvert
&& !lockres->l_ops->check_downconvert(lockres, new_level))
goto leave_requeue;
/* If we get here, then we know that there are no more
* incompatible holders (and anyone asking for an incompatible
* lock is blocked). We can now downconvert the lock */
if (!lockres->l_ops->downconvert_worker)
goto downconvert;
/* Some lockres types want to do a bit of work before
* downconverting a lock. Allow that here. The worker function
* may sleep, so we save off a copy of what we're blocking as
* it may change while we're not holding the spin lock. */
blocking = lockres->l_blocking;
spin_unlock_irqrestore(&lockres->l_lock, flags);
ctl->unblock_action = lockres->l_ops->downconvert_worker(lockres, blocking);
if (ctl->unblock_action == UNBLOCK_STOP_POST)
goto leave;
spin_lock_irqsave(&lockres->l_lock, flags);
if (blocking != lockres->l_blocking) {
/* If this changed underneath us, then we can't drop
* it just yet. */
goto recheck;
}
downconvert:
ctl->requeue = 0;
if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
if (lockres->l_level == DLM_LOCK_EX)
set_lvb = 1;
/*
* We only set the lvb if the lock has been fully
* refreshed - otherwise we risk setting stale
* data. Otherwise, there's no need to actually clear
* out the lvb here as it's value is still valid.
*/
if (set_lvb && !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
lockres->l_ops->set_lvb(lockres);
}
gen = ocfs2_prepare_downconvert(lockres, new_level);
spin_unlock_irqrestore(&lockres->l_lock, flags);
ret = ocfs2_downconvert_lock(osb, lockres, new_level, set_lvb,
gen);
leave:
mlog_exit(ret);
return ret;
leave_requeue:
spin_unlock_irqrestore(&lockres->l_lock, flags);
ctl->requeue = 1;
mlog_exit(0);
return 0;
}
static int ocfs2_data_convert_worker(struct ocfs2_lock_res *lockres,
int blocking)
{
struct inode *inode;
struct address_space *mapping;
inode = ocfs2_lock_res_inode(lockres);
mapping = inode->i_mapping;
if (!S_ISREG(inode->i_mode))
goto out;
/*
* We need this before the filemap_fdatawrite() so that it can
* transfer the dirty bit from the PTE to the
* page. Unfortunately this means that even for EX->PR
* downconverts, we'll lose our mappings and have to build
* them up again.
*/
unmap_mapping_range(mapping, 0, 0, 0);
if (filemap_fdatawrite(mapping)) {
mlog(ML_ERROR, "Could not sync inode %llu for downconvert!",
(unsigned long long)OCFS2_I(inode)->ip_blkno);
}
sync_mapping_buffers(mapping);
if (blocking == DLM_LOCK_EX) {
truncate_inode_pages(mapping, 0);
} else {
/* We only need to wait on the I/O if we're not also
* truncating pages because truncate_inode_pages waits
* for us above. We don't truncate pages if we're
* blocking anything < EXMODE because we want to keep
* them around in that case. */
filemap_fdatawait(mapping);
}
out:
return UNBLOCK_CONTINUE;
}
static int ocfs2_check_meta_downconvert(struct ocfs2_lock_res *lockres,
int new_level)
{
struct inode *inode = ocfs2_lock_res_inode(lockres);
int checkpointed = ocfs2_inode_fully_checkpointed(inode);
BUG_ON(new_level != DLM_LOCK_NL && new_level != DLM_LOCK_PR);
BUG_ON(lockres->l_level != DLM_LOCK_EX && !checkpointed);
if (checkpointed)
return 1;
ocfs2_start_checkpoint(OCFS2_SB(inode->i_sb));
return 0;
}
static void ocfs2_set_meta_lvb(struct ocfs2_lock_res *lockres)
{
struct inode *inode = ocfs2_lock_res_inode(lockres);
__ocfs2_stuff_meta_lvb(inode);
}
/*
* Does the final reference drop on our dentry lock. Right now this
* happens in the downconvert thread, but we could choose to simplify the
* dlmglue API and push these off to the ocfs2_wq in the future.
*/
static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
struct ocfs2_dentry_lock *dl = ocfs2_lock_res_dl(lockres);
ocfs2_dentry_lock_put(osb, dl);
}
/*
* d_delete() matching dentries before the lock downconvert.
*
* At this point, any process waiting to destroy the
* dentry_lock due to last ref count is stopped by the
* OCFS2_LOCK_QUEUED flag.
*
* We have two potential problems
*
* 1) If we do the last reference drop on our dentry_lock (via dput)
* we'll wind up in ocfs2_release_dentry_lock(), waiting on
* the downconvert to finish. Instead we take an elevated
* reference and push the drop until after we've completed our
* unblock processing.
*
* 2) There might be another process with a final reference,
* waiting on us to finish processing. If this is the case, we
* detect it and exit out - there's no more dentries anyway.
*/
static int ocfs2_dentry_convert_worker(struct ocfs2_lock_res *lockres,
int blocking)
{
struct ocfs2_dentry_lock *dl = ocfs2_lock_res_dl(lockres);
struct ocfs2_inode_info *oi = OCFS2_I(dl->dl_inode);
struct dentry *dentry;
unsigned long flags;
int extra_ref = 0;
/*
* This node is blocking another node from getting a read
* lock. This happens when we've renamed within a
* directory. We've forced the other nodes to d_delete(), but
* we never actually dropped our lock because it's still
* valid. The downconvert code will retain a PR for this node,
* so there's no further work to do.
*/
if (blocking == DLM_LOCK_PR)
return UNBLOCK_CONTINUE;
/*
* Mark this inode as potentially orphaned. The code in
* ocfs2_delete_inode() will figure out whether it actually
* needs to be freed or not.
*/
spin_lock(&oi->ip_lock);
oi->ip_flags |= OCFS2_INODE_MAYBE_ORPHANED;
spin_unlock(&oi->ip_lock);
/*
* Yuck. We need to make sure however that the check of
* OCFS2_LOCK_FREEING and the extra reference are atomic with
* respect to a reference decrement or the setting of that
* flag.
*/
spin_lock_irqsave(&lockres->l_lock, flags);
spin_lock(&dentry_attach_lock);
if (!(lockres->l_flags & OCFS2_LOCK_FREEING)
&& dl->dl_count) {
dl->dl_count++;
extra_ref = 1;
}
spin_unlock(&dentry_attach_lock);
spin_unlock_irqrestore(&lockres->l_lock, flags);
mlog(0, "extra_ref = %d\n", extra_ref);
/*
* We have a process waiting on us in ocfs2_dentry_iput(),
* which means we can't have any more outstanding
* aliases. There's no need to do any more work.
*/
if (!extra_ref)
return UNBLOCK_CONTINUE;
spin_lock(&dentry_attach_lock);
while (1) {
dentry = ocfs2_find_local_alias(dl->dl_inode,
dl->dl_parent_blkno, 1);
if (!dentry)
break;
spin_unlock(&dentry_attach_lock);
mlog(0, "d_delete(%.*s);\n", dentry->d_name.len,
dentry->d_name.name);
/*
* The following dcache calls may do an
* iput(). Normally we don't want that from the
* downconverting thread, but in this case it's ok
* because the requesting node already has an
* exclusive lock on the inode, so it can't be queued
* for a downconvert.
*/
d_delete(dentry);
dput(dentry);
spin_lock(&dentry_attach_lock);
}
spin_unlock(&dentry_attach_lock);
/*
* If we are the last holder of this dentry lock, there is no
* reason to downconvert so skip straight to the unlock.
*/
if (dl->dl_count == 1)
return UNBLOCK_STOP_POST;
return UNBLOCK_CONTINUE_POST;
}
/*
* This is the filesystem locking protocol. It provides the lock handling
* hooks for the underlying DLM. It has a maximum version number.
* The version number allows interoperability with systems running at
* the same major number and an equal or smaller minor number.
*
* Whenever the filesystem does new things with locks (adds or removes a
* lock, orders them differently, does different things underneath a lock),
* the version must be changed. The protocol is negotiated when joining
* the dlm domain. A node may join the domain if its major version is
* identical to all other nodes and its minor version is greater than
* or equal to all other nodes. When its minor version is greater than
* the other nodes, it will run at the minor version specified by the
* other nodes.
*
* If a locking change is made that will not be compatible with older
* versions, the major number must be increased and the minor version set
* to zero. If a change merely adds a behavior that can be disabled when
* speaking to older versions, the minor version must be increased. If a
* change adds a fully backwards compatible change (eg, LVB changes that
* are just ignored by older versions), the version does not need to be
* updated.
*/
static struct ocfs2_locking_protocol lproto = {
.lp_max_version = {
.pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR,
.pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR,
},
.lp_lock_ast = ocfs2_locking_ast,
.lp_blocking_ast = ocfs2_blocking_ast,
.lp_unlock_ast = ocfs2_unlock_ast,
};
void ocfs2_set_locking_protocol(void)
{
ocfs2_stack_glue_set_locking_protocol(&lproto);
}
static void ocfs2_process_blocked_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
int status;
struct ocfs2_unblock_ctl ctl = {0, 0,};
unsigned long flags;
/* Our reference to the lockres in this function can be
* considered valid until we remove the OCFS2_LOCK_QUEUED
* flag. */
mlog_entry_void();
BUG_ON(!lockres);
BUG_ON(!lockres->l_ops);
mlog(0, "lockres %s blocked.\n", lockres->l_name);
/* Detect whether a lock has been marked as going away while
* the downconvert thread was processing other things. A lock can
* still be marked with OCFS2_LOCK_FREEING after this check,
* but short circuiting here will still save us some
* performance. */
spin_lock_irqsave(&lockres->l_lock, flags);
if (lockres->l_flags & OCFS2_LOCK_FREEING)
goto unqueue;
spin_unlock_irqrestore(&lockres->l_lock, flags);
status = ocfs2_unblock_lock(osb, lockres, &ctl);
if (status < 0)
mlog_errno(status);
spin_lock_irqsave(&lockres->l_lock, flags);
unqueue:
if (lockres->l_flags & OCFS2_LOCK_FREEING || !ctl.requeue) {
lockres_clear_flags(lockres, OCFS2_LOCK_QUEUED);
} else
ocfs2_schedule_blocked_lock(osb, lockres);
mlog(0, "lockres %s, requeue = %s.\n", lockres->l_name,
ctl.requeue ? "yes" : "no");
spin_unlock_irqrestore(&lockres->l_lock, flags);
if (ctl.unblock_action != UNBLOCK_CONTINUE
&& lockres->l_ops->post_unlock)
lockres->l_ops->post_unlock(osb, lockres);
mlog_exit_void();
}
static void ocfs2_schedule_blocked_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres)
{
mlog_entry_void();
assert_spin_locked(&lockres->l_lock);
if (lockres->l_flags & OCFS2_LOCK_FREEING) {
/* Do not schedule a lock for downconvert when it's on
* the way to destruction - any nodes wanting access
* to the resource will get it soon. */
mlog(0, "Lockres %s won't be scheduled: flags 0x%lx\n",
lockres->l_name, lockres->l_flags);
return;
}
lockres_or_flags(lockres, OCFS2_LOCK_QUEUED);
spin_lock(&osb->dc_task_lock);
if (list_empty(&lockres->l_blocked_list)) {
list_add_tail(&lockres->l_blocked_list,
&osb->blocked_lock_list);
osb->blocked_lock_count++;
}
spin_unlock(&osb->dc_task_lock);
mlog_exit_void();
}
static void ocfs2_downconvert_thread_do_work(struct ocfs2_super *osb)
{
unsigned long processed;
struct ocfs2_lock_res *lockres;
mlog_entry_void();
spin_lock(&osb->dc_task_lock);
/* grab this early so we know to try again if a state change and
* wake happens part-way through our work */
osb->dc_work_sequence = osb->dc_wake_sequence;
processed = osb->blocked_lock_count;
while (processed) {
BUG_ON(list_empty(&osb->blocked_lock_list));
lockres = list_entry(osb->blocked_lock_list.next,
struct ocfs2_lock_res, l_blocked_list);
list_del_init(&lockres->l_blocked_list);
osb->blocked_lock_count--;
spin_unlock(&osb->dc_task_lock);
BUG_ON(!processed);
processed--;
ocfs2_process_blocked_lock(osb, lockres);
spin_lock(&osb->dc_task_lock);
}
spin_unlock(&osb->dc_task_lock);
mlog_exit_void();
}
static int ocfs2_downconvert_thread_lists_empty(struct ocfs2_super *osb)
{
int empty = 0;
spin_lock(&osb->dc_task_lock);
if (list_empty(&osb->blocked_lock_list))
empty = 1;
spin_unlock(&osb->dc_task_lock);
return empty;
}
static int ocfs2_downconvert_thread_should_wake(struct ocfs2_super *osb)
{
int should_wake = 0;
spin_lock(&osb->dc_task_lock);
if (osb->dc_work_sequence != osb->dc_wake_sequence)
should_wake = 1;
spin_unlock(&osb->dc_task_lock);
return should_wake;
}
static int ocfs2_downconvert_thread(void *arg)
{
int status = 0;
struct ocfs2_super *osb = arg;
/* only quit once we've been asked to stop and there is no more
* work available */
while (!(kthread_should_stop() &&
ocfs2_downconvert_thread_lists_empty(osb))) {
wait_event_interruptible(osb->dc_event,
ocfs2_downconvert_thread_should_wake(osb) ||
kthread_should_stop());
mlog(0, "downconvert_thread: awoken\n");
ocfs2_downconvert_thread_do_work(osb);
}
osb->dc_task = NULL;
return status;
}
void ocfs2_wake_downconvert_thread(struct ocfs2_super *osb)
{
spin_lock(&osb->dc_task_lock);
/* make sure the voting thread gets a swipe at whatever changes
* the caller may have made to the voting state */
osb->dc_wake_sequence++;
spin_unlock(&osb->dc_task_lock);
wake_up(&osb->dc_event);
}
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