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linux/fs/ocfs2/dlmglue.c
Joel Becker 9c6c877c04 ocfs2: Add the 'cluster_stack' sysfs file. 
Userspace can now query and specify the cluster stack in use via the
/sys/fs/ocfs2/cluster_stack file.  By default, it is 'o2cb', which is
the classic stack.  Thus, old tools that do not know how to modify this
file will work just fine.  The stack cannot be modified if there is a
live filesystem.

ocfs2_cluster_connect() now takes the expected cluster stack as an
argument.  This way, the filesystem and the stack glue ensure they are
speaking to the same backend.

If the stack is 'o2cb', the o2cb stack plugin is used.  For any other
value, the fsdlm stack plugin is selected.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:05 -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>
#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;
};
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);
}
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);
}
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);
}
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);
}
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 ? LKM_EXMODE : LKM_PRMODE;
unsigned int lkm_flags = trylock ? LKM_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, LKM_NLMODE, 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 |= LKM_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 == LKM_NLMODE)
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, LKM_NLMODE);
lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_BUSY, 0);
spin_unlock_irqrestore(&lockres->l_lock, flags);
ret = ocfs2_downconvert_lock(osb, lockres, LKM_NLMODE, 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(OCFS2_SB(inode->i_sb), oi->ip_blkno,
bh, OCFS2_BH_CACHED, inode);
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);
}
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(OCFS2_SB(inode->i_sb),
OCFS2_I(inode)->ip_blkno,
ret_bh,
OCFS2_BH_CACHED,
inode);
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);
}
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 1
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]);
/* 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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