linux-sg2042/fs/ocfs2/extent_map.c

518 lines
12 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* extent_map.c
*
* Block/Cluster mapping functions
*
* Copyright (C) 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, version 2, as published by the Free Software Foundation.
*
* 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/fs.h>
#include <linux/init.h>
#include <linux/types.h>
#define MLOG_MASK_PREFIX ML_EXTENT_MAP
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "alloc.h"
#include "extent_map.h"
#include "inode.h"
#include "super.h"
#include "buffer_head_io.h"
/*
* The extent caching implementation is intentionally trivial.
*
* We only cache a small number of extents stored directly on the
* inode, so linear order operations are acceptable. If we ever want
* to increase the size of the extent map, then these algorithms must
* get smarter.
*/
void ocfs2_extent_map_init(struct inode *inode)
{
struct ocfs2_inode_info *oi = OCFS2_I(inode);
oi->ip_extent_map.em_num_items = 0;
INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
}
static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
unsigned int cpos,
struct ocfs2_extent_map_item **ret_emi)
{
unsigned int range;
struct ocfs2_extent_map_item *emi;
*ret_emi = NULL;
list_for_each_entry(emi, &em->em_list, ei_list) {
range = emi->ei_cpos + emi->ei_clusters;
if (cpos >= emi->ei_cpos && cpos < range) {
list_move(&emi->ei_list, &em->em_list);
*ret_emi = emi;
break;
}
}
}
static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
unsigned int *phys, unsigned int *len,
unsigned int *flags)
{
unsigned int coff;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct ocfs2_extent_map_item *emi;
spin_lock(&oi->ip_lock);
__ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
if (emi) {
coff = cpos - emi->ei_cpos;
*phys = emi->ei_phys + coff;
if (len)
*len = emi->ei_clusters - coff;
if (flags)
*flags = emi->ei_flags;
}
spin_unlock(&oi->ip_lock);
if (emi == NULL)
return -ENOENT;
return 0;
}
/*
* Forget about all clusters equal to or greater than cpos.
*/
void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
{
struct ocfs2_extent_map_item *emi, *n;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct ocfs2_extent_map *em = &oi->ip_extent_map;
LIST_HEAD(tmp_list);
unsigned int range;
spin_lock(&oi->ip_lock);
list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
if (emi->ei_cpos >= cpos) {
/* Full truncate of this record. */
list_move(&emi->ei_list, &tmp_list);
BUG_ON(em->em_num_items == 0);
em->em_num_items--;
continue;
}
range = emi->ei_cpos + emi->ei_clusters;
if (range > cpos) {
/* Partial truncate */
emi->ei_clusters = cpos - emi->ei_cpos;
}
}
spin_unlock(&oi->ip_lock);
list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
list_del(&emi->ei_list);
kfree(emi);
}
}
/*
* Is any part of emi2 contained within emi1
*/
static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
struct ocfs2_extent_map_item *emi2)
{
unsigned int range1, range2;
/*
* Check if logical start of emi2 is inside emi1
*/
range1 = emi1->ei_cpos + emi1->ei_clusters;
if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
return 1;
/*
* Check if logical end of emi2 is inside emi1
*/
range2 = emi2->ei_cpos + emi2->ei_clusters;
if (range2 > emi1->ei_cpos && range2 <= range1)
return 1;
return 0;
}
static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
struct ocfs2_extent_map_item *src)
{
dest->ei_cpos = src->ei_cpos;
dest->ei_phys = src->ei_phys;
dest->ei_clusters = src->ei_clusters;
dest->ei_flags = src->ei_flags;
}
/*
* Try to merge emi with ins. Returns 1 if merge succeeds, zero
* otherwise.
*/
static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
struct ocfs2_extent_map_item *ins)
{
/*
* Handle contiguousness
*/
if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
ins->ei_flags == emi->ei_flags) {
emi->ei_clusters += ins->ei_clusters;
return 1;
} else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
(ins->ei_cpos + ins->ei_clusters) == emi->ei_phys &&
ins->ei_flags == emi->ei_flags) {
emi->ei_phys = ins->ei_phys;
emi->ei_cpos = ins->ei_cpos;
emi->ei_clusters += ins->ei_clusters;
return 1;
}
/*
* Overlapping extents - this shouldn't happen unless we've
* split an extent to change it's flags. That is exceedingly
* rare, so there's no sense in trying to optimize it yet.
*/
if (ocfs2_ei_is_contained(emi, ins) ||
ocfs2_ei_is_contained(ins, emi)) {
ocfs2_copy_emi_fields(emi, ins);
return 1;
}
/* No merge was possible. */
return 0;
}
/*
* In order to reduce complexity on the caller, this insert function
* is intentionally liberal in what it will accept.
*
* The only rule is that the truncate call *must* be used whenever
* records have been deleted. This avoids inserting overlapping
* records with different physical mappings.
*/
void ocfs2_extent_map_insert_rec(struct inode *inode,
struct ocfs2_extent_rec *rec)
{
struct ocfs2_inode_info *oi = OCFS2_I(inode);
struct ocfs2_extent_map *em = &oi->ip_extent_map;
struct ocfs2_extent_map_item *emi, *new_emi = NULL;
struct ocfs2_extent_map_item ins;
ins.ei_cpos = le32_to_cpu(rec->e_cpos);
ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
le64_to_cpu(rec->e_blkno));
ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
ins.ei_flags = rec->e_flags;
search:
spin_lock(&oi->ip_lock);
list_for_each_entry(emi, &em->em_list, ei_list) {
if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
list_move(&emi->ei_list, &em->em_list);
spin_unlock(&oi->ip_lock);
goto out;
}
}
/*
* No item could be merged.
*
* Either allocate and add a new item, or overwrite the last recently
* inserted.
*/
if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
if (new_emi == NULL) {
spin_unlock(&oi->ip_lock);
new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
if (new_emi == NULL)
goto out;
goto search;
}
ocfs2_copy_emi_fields(new_emi, &ins);
list_add(&new_emi->ei_list, &em->em_list);
em->em_num_items++;
new_emi = NULL;
} else {
BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
emi = list_entry(em->em_list.prev,
struct ocfs2_extent_map_item, ei_list);
list_move(&emi->ei_list, &em->em_list);
ocfs2_copy_emi_fields(emi, &ins);
}
spin_unlock(&oi->ip_lock);
out:
if (new_emi)
kfree(new_emi);
}
/*
* Return the 1st index within el which contains an extent start
* larger than v_cluster.
*/
static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
u32 v_cluster)
{
int i;
struct ocfs2_extent_rec *rec;
for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
rec = &el->l_recs[i];
if (v_cluster < le32_to_cpu(rec->e_cpos))
break;
}
return i;
}
/*
* Figure out the size of a hole which starts at v_cluster within the given
* extent list.
*
* If there is no more allocation past v_cluster, we return the maximum
* cluster size minus v_cluster.
*
* If we have in-inode extents, then el points to the dinode list and
* eb_bh is NULL. Otherwise, eb_bh should point to the extent block
* containing el.
*/
static int ocfs2_figure_hole_clusters(struct inode *inode,
struct ocfs2_extent_list *el,
struct buffer_head *eb_bh,
u32 v_cluster,
u32 *num_clusters)
{
int ret, i;
struct buffer_head *next_eb_bh = NULL;
struct ocfs2_extent_block *eb, *next_eb;
i = ocfs2_search_for_hole_index(el, v_cluster);
if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
eb = (struct ocfs2_extent_block *)eb_bh->b_data;
/*
* Check the next leaf for any extents.
*/
if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
goto no_more_extents;
ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
le64_to_cpu(eb->h_next_leaf_blk),
&next_eb_bh, OCFS2_BH_CACHED, inode);
if (ret) {
mlog_errno(ret);
goto out;
}
next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
if (!OCFS2_IS_VALID_EXTENT_BLOCK(next_eb)) {
ret = -EROFS;
OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, next_eb);
goto out;
}
el = &next_eb->h_list;
i = ocfs2_search_for_hole_index(el, v_cluster);
}
no_more_extents:
if (i == le16_to_cpu(el->l_next_free_rec)) {
/*
* We're at the end of our existing allocation. Just
* return the maximum number of clusters we could
* possibly allocate.
*/
*num_clusters = UINT_MAX - v_cluster;
} else {
*num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
}
ret = 0;
out:
brelse(next_eb_bh);
return ret;
}
int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
u32 *p_cluster, u32 *num_clusters,
unsigned int *extent_flags)
{
int ret, i;
unsigned int flags = 0;
struct buffer_head *di_bh = NULL;
struct buffer_head *eb_bh = NULL;
struct ocfs2_dinode *di;
struct ocfs2_extent_block *eb;
struct ocfs2_extent_list *el;
struct ocfs2_extent_rec *rec;
u32 coff;
ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
num_clusters, extent_flags);
if (ret == 0)
goto out;
ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), OCFS2_I(inode)->ip_blkno,
&di_bh, OCFS2_BH_CACHED, inode);
if (ret) {
mlog_errno(ret);
goto out;
}
di = (struct ocfs2_dinode *) di_bh->b_data;
el = &di->id2.i_list;
if (el->l_tree_depth) {
ret = ocfs2_find_leaf(inode, el, v_cluster, &eb_bh);
if (ret) {
mlog_errno(ret);
goto out;
}
eb = (struct ocfs2_extent_block *) eb_bh->b_data;
el = &eb->h_list;
if (el->l_tree_depth) {
ocfs2_error(inode->i_sb,
"Inode %lu has non zero tree depth in "
"leaf block %llu\n", inode->i_ino,
(unsigned long long)eb_bh->b_blocknr);
ret = -EROFS;
goto out;
}
}
i = ocfs2_search_extent_list(el, v_cluster);
if (i == -1) {
/*
* A hole was found. Return some canned values that
* callers can key on. If asked for, num_clusters will
* be populated with the size of the hole.
*/
*p_cluster = 0;
if (num_clusters) {
ret = ocfs2_figure_hole_clusters(inode, el, eb_bh,
v_cluster,
num_clusters);
if (ret) {
mlog_errno(ret);
goto out;
}
}
} else {
rec = &el->l_recs[i];
BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
if (!rec->e_blkno) {
ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
"record (%u, %u, 0)", inode->i_ino,
le32_to_cpu(rec->e_cpos),
ocfs2_rec_clusters(el, rec));
ret = -EROFS;
goto out;
}
coff = v_cluster - le32_to_cpu(rec->e_cpos);
*p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
le64_to_cpu(rec->e_blkno));
*p_cluster = *p_cluster + coff;
if (num_clusters)
*num_clusters = ocfs2_rec_clusters(el, rec) - coff;
flags = rec->e_flags;
ocfs2_extent_map_insert_rec(inode, rec);
}
if (extent_flags)
*extent_flags = flags;
out:
brelse(di_bh);
brelse(eb_bh);
return ret;
}
/*
* This expects alloc_sem to be held. The allocation cannot change at
* all while the map is in the process of being updated.
*/
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;
}