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linux-next/fs/ocfs2/ocfs2_lockid.h
Srinivas Eeda 83273932fb ocfs2: timer to queue scan of all orphan slots
When a dentry is unlinked, the unlinking node takes an EX on the dentry lock
before moving the dentry to the orphan directory. Other nodes that have
this dentry in cache have a PR on the same dentry lock.  When the EX is
requested, the other nodes flag the corresponding inode as MAYBE_ORPHANED
during downconvert.  The inode is finally deleted when the last node to iput
the inode sees that i_nlink==0 and the MAYBE_ORPHANED flag is set.

A problem arises if a node is forced to free dentry locks because of memory
pressure. If this happens, the node will no longer get downconvert
notifications for the dentries that have been unlinked on another node.
If it also happens that node is actively using the corresponding inode and
happens to be the one performing the last iput on that inode, it will fail
to delete the inode as it will not have the MAYBE_ORPHANED flag set.

This patch fixes this shortcoming by introducing a periodic scan of the
orphan directories to delete such inodes. Care has been taken to distribute
the workload across the cluster so that no one node has to perform the task
all the time.

Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
2009-06-03 19:14:31 -07:00

123 lines
3.0 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* ocfs2_lockid.h
*
* Defines OCFS2 lockid bits.
*
* Copyright (C) 2002, 2005 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.
*/
#ifndef OCFS2_LOCKID_H
#define OCFS2_LOCKID_H
/* lock ids are made up in the following manner:
* name[0] --> type
* name[1-6] --> 6 pad characters, reserved for now
* name[7-22] --> block number, expressed in hex as 16 chars
* name[23-30] --> i_generation, expressed in hex 8 chars
* name[31] --> '\0' */
#define OCFS2_LOCK_ID_MAX_LEN 32
#define OCFS2_LOCK_ID_PAD "000000"
#define OCFS2_DENTRY_LOCK_INO_START 18
enum ocfs2_lock_type {
OCFS2_LOCK_TYPE_META = 0,
OCFS2_LOCK_TYPE_DATA,
OCFS2_LOCK_TYPE_SUPER,
OCFS2_LOCK_TYPE_RENAME,
OCFS2_LOCK_TYPE_RW,
OCFS2_LOCK_TYPE_DENTRY,
OCFS2_LOCK_TYPE_OPEN,
OCFS2_LOCK_TYPE_FLOCK,
OCFS2_LOCK_TYPE_QINFO,
OCFS2_LOCK_TYPE_NFS_SYNC,
OCFS2_LOCK_TYPE_ORPHAN_SCAN,
OCFS2_NUM_LOCK_TYPES
};
static inline char ocfs2_lock_type_char(enum ocfs2_lock_type type)
{
char c;
switch (type) {
case OCFS2_LOCK_TYPE_META:
c = 'M';
break;
case OCFS2_LOCK_TYPE_DATA:
c = 'D';
break;
case OCFS2_LOCK_TYPE_SUPER:
c = 'S';
break;
case OCFS2_LOCK_TYPE_RENAME:
c = 'R';
break;
case OCFS2_LOCK_TYPE_RW:
c = 'W';
break;
case OCFS2_LOCK_TYPE_DENTRY:
c = 'N';
break;
case OCFS2_LOCK_TYPE_OPEN:
c = 'O';
break;
case OCFS2_LOCK_TYPE_FLOCK:
c = 'F';
break;
case OCFS2_LOCK_TYPE_QINFO:
c = 'Q';
break;
case OCFS2_LOCK_TYPE_NFS_SYNC:
c = 'Y';
break;
case OCFS2_LOCK_TYPE_ORPHAN_SCAN:
c = 'P';
break;
default:
c = '\0';
}
return c;
}
static char *ocfs2_lock_type_strings[] = {
[OCFS2_LOCK_TYPE_META] = "Meta",
[OCFS2_LOCK_TYPE_DATA] = "Data",
[OCFS2_LOCK_TYPE_SUPER] = "Super",
[OCFS2_LOCK_TYPE_RENAME] = "Rename",
/* Need to differntiate from [R]ename.. serializing writes is the
* important job it does, anyway. */
[OCFS2_LOCK_TYPE_RW] = "Write/Read",
[OCFS2_LOCK_TYPE_DENTRY] = "Dentry",
[OCFS2_LOCK_TYPE_OPEN] = "Open",
[OCFS2_LOCK_TYPE_FLOCK] = "Flock",
[OCFS2_LOCK_TYPE_QINFO] = "Quota",
[OCFS2_LOCK_TYPE_ORPHAN_SCAN] = "OrphanScan",
};
static inline const char *ocfs2_lock_type_string(enum ocfs2_lock_type type)
{
#ifdef __KERNEL__
BUG_ON(type >= OCFS2_NUM_LOCK_TYPES);
#endif
return ocfs2_lock_type_strings[type];
}
#endif /* OCFS2_LOCKID_H */