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24c19ef404
OCFS2 puts inode meta data in the "lock value block" provided by the DLM. Typically, i_generation is encoded in the lock name so that a deleted inode on and a new one in the same block don't share the same lvb. Unfortunately, that scheme means that the read in ocfs2_read_locked_inode() is potentially thrown away as soon as the meta data lock is taken - we cannot encode the lock name without first knowing i_generation, which requires a disk read. This patch encodes i_generation in the inode meta data lvb, and removes the value from the inode meta data lock name. This way, the read can be covered by a lock, and at the same time we can distinguish between an up to date and a stale LVB. This will help cold-cache stat(2) performance in particular. Since this patch changes the protocol version, we take the opportunity to do a minor re-organization of two of the LVB fields. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
130 lines
3.2 KiB
C
130 lines
3.2 KiB
C
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* sysfile.c
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*
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* Initialize, read, write, etc. system files.
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*
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* Copyright (C) 2002, 2004 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/fs.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/highmem.h>
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#define MLOG_MASK_PREFIX ML_INODE
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#include <cluster/masklog.h>
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#include "ocfs2.h"
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#include "alloc.h"
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#include "dir.h"
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#include "inode.h"
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#include "journal.h"
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#include "sysfile.h"
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#include "buffer_head_io.h"
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static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
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int type,
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u32 slot);
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static inline int is_global_system_inode(int type);
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static inline int is_in_system_inode_array(struct ocfs2_super *osb,
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int type,
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u32 slot);
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static inline int is_global_system_inode(int type)
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{
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return type >= OCFS2_FIRST_ONLINE_SYSTEM_INODE &&
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type <= OCFS2_LAST_GLOBAL_SYSTEM_INODE;
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}
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static inline int is_in_system_inode_array(struct ocfs2_super *osb,
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int type,
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u32 slot)
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{
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return slot == osb->slot_num || is_global_system_inode(type);
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}
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struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb,
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int type,
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u32 slot)
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{
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struct inode *inode = NULL;
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struct inode **arr = NULL;
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/* avoid the lookup if cached in local system file array */
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if (is_in_system_inode_array(osb, type, slot))
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arr = &(osb->system_inodes[type]);
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if (arr && ((inode = *arr) != NULL)) {
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/* get a ref in addition to the array ref */
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inode = igrab(inode);
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BUG_ON(!inode);
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return inode;
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}
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/* this gets one ref thru iget */
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inode = _ocfs2_get_system_file_inode(osb, type, slot);
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/* add one more if putting into array for first time */
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if (arr && inode) {
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*arr = igrab(inode);
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BUG_ON(!*arr);
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}
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return inode;
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}
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static struct inode * _ocfs2_get_system_file_inode(struct ocfs2_super *osb,
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int type,
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u32 slot)
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{
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char namebuf[40];
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struct inode *inode = NULL;
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u64 blkno;
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struct buffer_head *dirent_bh = NULL;
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struct ocfs2_dir_entry *de = NULL;
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int status = 0;
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ocfs2_sprintf_system_inode_name(namebuf,
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sizeof(namebuf),
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type, slot);
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status = ocfs2_find_files_on_disk(namebuf, strlen(namebuf),
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&blkno, osb->sys_root_inode,
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&dirent_bh, &de);
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if (status < 0) {
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goto bail;
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}
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inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE);
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if (IS_ERR(inode)) {
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mlog_errno(PTR_ERR(inode));
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inode = NULL;
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goto bail;
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}
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bail:
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if (dirent_bh)
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brelse(dirent_bh);
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return inode;
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}
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