549 lines
13 KiB
C
549 lines
13 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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* extent_map.c
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*
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* Block/Cluster mapping functions
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*
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* Copyright (C) 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, version 2, as published by the Free Software Foundation.
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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/init.h>
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#include <linux/types.h>
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#define MLOG_MASK_PREFIX ML_EXTENT_MAP
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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 "extent_map.h"
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#include "inode.h"
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#include "super.h"
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#include "buffer_head_io.h"
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/*
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* The extent caching implementation is intentionally trivial.
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*
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* We only cache a small number of extents stored directly on the
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* inode, so linear order operations are acceptable. If we ever want
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* to increase the size of the extent map, then these algorithms must
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* get smarter.
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*/
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void ocfs2_extent_map_init(struct inode *inode)
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{
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struct ocfs2_inode_info *oi = OCFS2_I(inode);
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oi->ip_extent_map.em_num_items = 0;
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INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
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}
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static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
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unsigned int cpos,
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struct ocfs2_extent_map_item **ret_emi)
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{
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unsigned int range;
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struct ocfs2_extent_map_item *emi;
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*ret_emi = NULL;
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list_for_each_entry(emi, &em->em_list, ei_list) {
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range = emi->ei_cpos + emi->ei_clusters;
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if (cpos >= emi->ei_cpos && cpos < range) {
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list_move(&emi->ei_list, &em->em_list);
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*ret_emi = emi;
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break;
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}
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}
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}
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static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
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unsigned int *phys, unsigned int *len,
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unsigned int *flags)
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{
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unsigned int coff;
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struct ocfs2_inode_info *oi = OCFS2_I(inode);
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struct ocfs2_extent_map_item *emi;
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spin_lock(&oi->ip_lock);
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__ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
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if (emi) {
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coff = cpos - emi->ei_cpos;
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*phys = emi->ei_phys + coff;
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if (len)
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*len = emi->ei_clusters - coff;
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if (flags)
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*flags = emi->ei_flags;
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}
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spin_unlock(&oi->ip_lock);
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if (emi == NULL)
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return -ENOENT;
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return 0;
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}
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/*
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* Forget about all clusters equal to or greater than cpos.
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*/
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void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
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{
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struct ocfs2_extent_map_item *emi, *n;
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struct ocfs2_inode_info *oi = OCFS2_I(inode);
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struct ocfs2_extent_map *em = &oi->ip_extent_map;
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LIST_HEAD(tmp_list);
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unsigned int range;
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spin_lock(&oi->ip_lock);
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list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
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if (emi->ei_cpos >= cpos) {
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/* Full truncate of this record. */
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list_move(&emi->ei_list, &tmp_list);
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BUG_ON(em->em_num_items == 0);
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em->em_num_items--;
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continue;
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}
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range = emi->ei_cpos + emi->ei_clusters;
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if (range > cpos) {
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/* Partial truncate */
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emi->ei_clusters = cpos - emi->ei_cpos;
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}
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}
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spin_unlock(&oi->ip_lock);
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list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
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list_del(&emi->ei_list);
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kfree(emi);
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}
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}
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/*
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* Is any part of emi2 contained within emi1
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*/
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static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
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struct ocfs2_extent_map_item *emi2)
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{
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unsigned int range1, range2;
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/*
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* Check if logical start of emi2 is inside emi1
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*/
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range1 = emi1->ei_cpos + emi1->ei_clusters;
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if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
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return 1;
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/*
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* Check if logical end of emi2 is inside emi1
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*/
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range2 = emi2->ei_cpos + emi2->ei_clusters;
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if (range2 > emi1->ei_cpos && range2 <= range1)
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return 1;
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return 0;
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}
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static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
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struct ocfs2_extent_map_item *src)
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{
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dest->ei_cpos = src->ei_cpos;
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dest->ei_phys = src->ei_phys;
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dest->ei_clusters = src->ei_clusters;
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dest->ei_flags = src->ei_flags;
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}
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/*
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* Try to merge emi with ins. Returns 1 if merge succeeds, zero
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* otherwise.
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*/
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static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
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struct ocfs2_extent_map_item *ins)
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{
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/*
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* Handle contiguousness
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*/
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if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
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ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
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ins->ei_flags == emi->ei_flags) {
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emi->ei_clusters += ins->ei_clusters;
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return 1;
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} else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
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(ins->ei_cpos + ins->ei_clusters) == emi->ei_phys &&
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ins->ei_flags == emi->ei_flags) {
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emi->ei_phys = ins->ei_phys;
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emi->ei_cpos = ins->ei_cpos;
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emi->ei_clusters += ins->ei_clusters;
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return 1;
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}
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/*
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* Overlapping extents - this shouldn't happen unless we've
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* split an extent to change it's flags. That is exceedingly
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* rare, so there's no sense in trying to optimize it yet.
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*/
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if (ocfs2_ei_is_contained(emi, ins) ||
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ocfs2_ei_is_contained(ins, emi)) {
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ocfs2_copy_emi_fields(emi, ins);
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return 1;
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}
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/* No merge was possible. */
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return 0;
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}
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/*
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* In order to reduce complexity on the caller, this insert function
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* is intentionally liberal in what it will accept.
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*
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* The only rule is that the truncate call *must* be used whenever
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* records have been deleted. This avoids inserting overlapping
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* records with different physical mappings.
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*/
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void ocfs2_extent_map_insert_rec(struct inode *inode,
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struct ocfs2_extent_rec *rec)
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{
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struct ocfs2_inode_info *oi = OCFS2_I(inode);
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struct ocfs2_extent_map *em = &oi->ip_extent_map;
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struct ocfs2_extent_map_item *emi, *new_emi = NULL;
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struct ocfs2_extent_map_item ins;
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ins.ei_cpos = le32_to_cpu(rec->e_cpos);
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ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
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le64_to_cpu(rec->e_blkno));
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ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
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ins.ei_flags = rec->e_flags;
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search:
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spin_lock(&oi->ip_lock);
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list_for_each_entry(emi, &em->em_list, ei_list) {
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if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
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list_move(&emi->ei_list, &em->em_list);
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spin_unlock(&oi->ip_lock);
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goto out;
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}
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}
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/*
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* No item could be merged.
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*
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* Either allocate and add a new item, or overwrite the last recently
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* inserted.
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*/
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if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
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if (new_emi == NULL) {
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spin_unlock(&oi->ip_lock);
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new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
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if (new_emi == NULL)
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goto out;
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goto search;
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}
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ocfs2_copy_emi_fields(new_emi, &ins);
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list_add(&new_emi->ei_list, &em->em_list);
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em->em_num_items++;
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new_emi = NULL;
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} else {
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BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
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emi = list_entry(em->em_list.prev,
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struct ocfs2_extent_map_item, ei_list);
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list_move(&emi->ei_list, &em->em_list);
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ocfs2_copy_emi_fields(emi, &ins);
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}
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spin_unlock(&oi->ip_lock);
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out:
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if (new_emi)
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kfree(new_emi);
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}
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/*
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* Return the 1st index within el which contains an extent start
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* larger than v_cluster.
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*/
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static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
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u32 v_cluster)
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{
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int i;
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struct ocfs2_extent_rec *rec;
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for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
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rec = &el->l_recs[i];
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if (v_cluster < le32_to_cpu(rec->e_cpos))
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break;
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}
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return i;
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}
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/*
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* Figure out the size of a hole which starts at v_cluster within the given
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* extent list.
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*
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* If there is no more allocation past v_cluster, we return the maximum
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* cluster size minus v_cluster.
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*
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* If we have in-inode extents, then el points to the dinode list and
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* eb_bh is NULL. Otherwise, eb_bh should point to the extent block
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* containing el.
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*/
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static int ocfs2_figure_hole_clusters(struct inode *inode,
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struct ocfs2_extent_list *el,
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struct buffer_head *eb_bh,
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u32 v_cluster,
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u32 *num_clusters)
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{
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int ret, i;
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struct buffer_head *next_eb_bh = NULL;
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struct ocfs2_extent_block *eb, *next_eb;
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i = ocfs2_search_for_hole_index(el, v_cluster);
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if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
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eb = (struct ocfs2_extent_block *)eb_bh->b_data;
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/*
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* Check the next leaf for any extents.
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*/
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if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
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goto no_more_extents;
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ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
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le64_to_cpu(eb->h_next_leaf_blk),
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&next_eb_bh, OCFS2_BH_CACHED, inode);
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if (ret) {
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mlog_errno(ret);
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goto out;
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}
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next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
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if (!OCFS2_IS_VALID_EXTENT_BLOCK(next_eb)) {
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ret = -EROFS;
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OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, next_eb);
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goto out;
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}
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el = &next_eb->h_list;
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i = ocfs2_search_for_hole_index(el, v_cluster);
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}
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no_more_extents:
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if (i == le16_to_cpu(el->l_next_free_rec)) {
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/*
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* We're at the end of our existing allocation. Just
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* return the maximum number of clusters we could
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* possibly allocate.
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*/
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*num_clusters = UINT_MAX - v_cluster;
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} else {
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*num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
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}
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ret = 0;
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out:
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brelse(next_eb_bh);
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return ret;
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}
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/*
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* Return the index of the extent record which contains cluster #v_cluster.
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* -1 is returned if it was not found.
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*
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* Should work fine on interior and exterior nodes.
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*/
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static int ocfs2_search_extent_list(struct ocfs2_extent_list *el,
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u32 v_cluster)
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{
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int ret = -1;
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int i;
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struct ocfs2_extent_rec *rec;
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u32 rec_end, rec_start, clusters;
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for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
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rec = &el->l_recs[i];
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rec_start = le32_to_cpu(rec->e_cpos);
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clusters = ocfs2_rec_clusters(el, rec);
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rec_end = rec_start + clusters;
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if (v_cluster >= rec_start && v_cluster < rec_end) {
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ret = i;
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break;
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}
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}
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return ret;
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}
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int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
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u32 *p_cluster, u32 *num_clusters,
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unsigned int *extent_flags)
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{
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int ret, i;
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unsigned int flags = 0;
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struct buffer_head *di_bh = NULL;
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struct buffer_head *eb_bh = NULL;
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struct ocfs2_dinode *di;
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struct ocfs2_extent_block *eb;
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struct ocfs2_extent_list *el;
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struct ocfs2_extent_rec *rec;
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u32 coff;
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ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
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num_clusters, extent_flags);
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if (ret == 0)
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goto out;
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ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), OCFS2_I(inode)->ip_blkno,
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&di_bh, OCFS2_BH_CACHED, inode);
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if (ret) {
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mlog_errno(ret);
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goto out;
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}
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di = (struct ocfs2_dinode *) di_bh->b_data;
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el = &di->id2.i_list;
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if (el->l_tree_depth) {
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ret = ocfs2_find_leaf(inode, el, v_cluster, &eb_bh);
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if (ret) {
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mlog_errno(ret);
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goto out;
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}
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eb = (struct ocfs2_extent_block *) eb_bh->b_data;
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el = &eb->h_list;
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if (el->l_tree_depth) {
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ocfs2_error(inode->i_sb,
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"Inode %lu has non zero tree depth in "
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"leaf block %llu\n", inode->i_ino,
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(unsigned long long)eb_bh->b_blocknr);
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ret = -EROFS;
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goto out;
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}
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}
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i = ocfs2_search_extent_list(el, v_cluster);
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if (i == -1) {
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/*
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* A hole was found. Return some canned values that
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* callers can key on. If asked for, num_clusters will
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* be populated with the size of the hole.
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*/
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*p_cluster = 0;
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if (num_clusters) {
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ret = ocfs2_figure_hole_clusters(inode, el, eb_bh,
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v_cluster,
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num_clusters);
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if (ret) {
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mlog_errno(ret);
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goto out;
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}
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}
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} else {
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rec = &el->l_recs[i];
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BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
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if (!rec->e_blkno) {
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ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
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"record (%u, %u, 0)", inode->i_ino,
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le32_to_cpu(rec->e_cpos),
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ocfs2_rec_clusters(el, rec));
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ret = -EROFS;
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goto out;
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}
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coff = v_cluster - le32_to_cpu(rec->e_cpos);
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*p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
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le64_to_cpu(rec->e_blkno));
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*p_cluster = *p_cluster + coff;
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if (num_clusters)
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*num_clusters = ocfs2_rec_clusters(el, rec) - coff;
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flags = rec->e_flags;
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ocfs2_extent_map_insert_rec(inode, rec);
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}
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if (extent_flags)
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*extent_flags = flags;
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out:
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brelse(di_bh);
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brelse(eb_bh);
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return ret;
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}
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/*
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* This expects alloc_sem to be held. The allocation cannot change at
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* all while the map is in the process of being updated.
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*/
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int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
|
|
u64 *ret_count, unsigned int *extent_flags)
|
|
{
|
|
int ret;
|
|
int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
|
|
u32 cpos, num_clusters, p_cluster;
|
|
u64 boff = 0;
|
|
|
|
cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
|
|
|
|
ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
|
|
extent_flags);
|
|
if (ret) {
|
|
mlog_errno(ret);
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* p_cluster == 0 indicates a hole.
|
|
*/
|
|
if (p_cluster) {
|
|
boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
|
|
boff += (v_blkno & (u64)(bpc - 1));
|
|
}
|
|
|
|
*p_blkno = boff;
|
|
|
|
if (ret_count) {
|
|
*ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
|
|
*ret_count -= v_blkno & (u64)(bpc - 1);
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|