linux/fs/ocfs2/extent_map.c

997 lines
23 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/slab.h>
#include <linux/types.h>
#include <linux/fiemap.h>
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "alloc.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "inode.h"
#include "super.h"
#include "symlink.h"
#include "ocfs2_trace.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_cpos &&
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);
}
static int ocfs2_last_eb_is_empty(struct inode *inode,
struct ocfs2_dinode *di)
{
int ret, next_free;
u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
struct buffer_head *eb_bh = NULL;
struct ocfs2_extent_block *eb;
struct ocfs2_extent_list *el;
ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &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;
}
next_free = le16_to_cpu(el->l_next_free_rec);
if (next_free == 0 ||
(next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
ret = 1;
out:
brelse(eb_bh);
return ret;
}
/*
* 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.
*/
int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
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_extent_block(ci,
le64_to_cpu(eb->h_next_leaf_blk),
&next_eb_bh);
if (ret) {
mlog_errno(ret);
goto out;
}
next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
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;
}
static int ocfs2_get_clusters_nocache(struct inode *inode,
struct buffer_head *di_bh,
u32 v_cluster, unsigned int *hole_len,
struct ocfs2_extent_rec *ret_rec,
unsigned int *is_last)
{
int i, ret, tree_height, len;
struct ocfs2_dinode *di;
struct ocfs2_extent_block *uninitialized_var(eb);
struct ocfs2_extent_list *el;
struct ocfs2_extent_rec *rec;
struct buffer_head *eb_bh = NULL;
memset(ret_rec, 0, sizeof(*ret_rec));
if (is_last)
*is_last = 0;
di = (struct ocfs2_dinode *) di_bh->b_data;
el = &di->id2.i_list;
tree_height = le16_to_cpu(el->l_tree_depth);
if (tree_height > 0) {
ret = ocfs2_find_leaf(INODE_CACHE(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) {
/*
* Holes can be larger than the maximum size of an
* extent, so we return their lengths in a separate
* field.
*/
if (hole_len) {
ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
el, eb_bh,
v_cluster, &len);
if (ret) {
mlog_errno(ret);
goto out;
}
*hole_len = len;
}
goto out_hole;
}
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;
}
*ret_rec = *rec;
/*
* Checking for last extent is potentially expensive - we
* might have to look at the next leaf over to see if it's
* empty.
*
* The first two checks are to see whether the caller even
* cares for this information, and if the extent is at least
* the last in it's list.
*
* If those hold true, then the extent is last if any of the
* additional conditions hold true:
* - Extent list is in-inode
* - Extent list is right-most
* - Extent list is 2nd to rightmost, with empty right-most
*/
if (is_last) {
if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
if (tree_height == 0)
*is_last = 1;
else if (eb->h_blkno == di->i_last_eb_blk)
*is_last = 1;
else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
ret = ocfs2_last_eb_is_empty(inode, di);
if (ret < 0) {
mlog_errno(ret);
goto out;
}
if (ret == 1)
*is_last = 1;
}
}
}
out_hole:
ret = 0;
out:
brelse(eb_bh);
return ret;
}
static void ocfs2_relative_extent_offsets(struct super_block *sb,
u32 v_cluster,
struct ocfs2_extent_rec *rec,
u32 *p_cluster, u32 *num_clusters)
{
u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
*p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
*p_cluster = *p_cluster + coff;
if (num_clusters)
*num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
}
int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
u32 *p_cluster, u32 *num_clusters,
struct ocfs2_extent_list *el,
unsigned int *extent_flags)
{
int ret = 0, i;
struct buffer_head *eb_bh = NULL;
struct ocfs2_extent_block *eb;
struct ocfs2_extent_rec *rec;
u32 coff;
if (el->l_tree_depth) {
ret = ocfs2_find_leaf(INODE_CACHE(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 "
"xattr 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) {
ret = -EROFS;
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) in xattr", 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;
if (extent_flags)
*extent_flags = rec->e_flags;
}
out:
if (eb_bh)
brelse(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;
unsigned int uninitialized_var(hole_len), flags = 0;
struct buffer_head *di_bh = NULL;
struct ocfs2_extent_rec rec;
if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
ret = -ERANGE;
mlog_errno(ret);
goto out;
}
ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
num_clusters, extent_flags);
if (ret == 0)
goto out;
ret = ocfs2_read_inode_block(inode, &di_bh);
if (ret) {
mlog_errno(ret);
goto out;
}
ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
&rec, NULL);
if (ret) {
mlog_errno(ret);
goto out;
}
if (rec.e_blkno == 0ULL) {
/*
* 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) {
*num_clusters = hole_len;
}
} else {
ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
p_cluster, num_clusters);
flags = rec.e_flags;
ocfs2_extent_map_insert_rec(inode, &rec);
}
if (extent_flags)
*extent_flags = flags;
out:
brelse(di_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;
}
/*
* The ocfs2_fiemap_inline() may be a little bit misleading, since
* it not only handles the fiemap for inlined files, but also deals
* with the fast symlink, cause they have no difference for extent
* mapping per se.
*/
static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
struct fiemap_extent_info *fieinfo,
u64 map_start)
{
int ret;
unsigned int id_count;
struct ocfs2_dinode *di;
u64 phys;
u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
struct ocfs2_inode_info *oi = OCFS2_I(inode);
di = (struct ocfs2_dinode *)di_bh->b_data;
if (ocfs2_inode_is_fast_symlink(inode))
id_count = ocfs2_fast_symlink_chars(inode->i_sb);
else
id_count = le16_to_cpu(di->id2.i_data.id_count);
if (map_start < id_count) {
phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
if (ocfs2_inode_is_fast_symlink(inode))
phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
else
phys += offsetof(struct ocfs2_dinode,
id2.i_data.id_data);
ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
flags);
if (ret < 0)
return ret;
}
return 0;
}
#define OCFS2_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC)
int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 map_start, u64 map_len)
{
int ret, is_last;
u32 mapping_end, cpos;
unsigned int hole_size;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
u64 len_bytes, phys_bytes, virt_bytes;
struct buffer_head *di_bh = NULL;
struct ocfs2_extent_rec rec;
ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
if (ret)
return ret;
ret = ocfs2_inode_lock(inode, &di_bh, 0);
if (ret) {
mlog_errno(ret);
goto out;
}
down_read(&OCFS2_I(inode)->ip_alloc_sem);
/*
* Handle inline-data and fast symlink separately.
*/
if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
ocfs2_inode_is_fast_symlink(inode)) {
ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
goto out_unlock;
}
cpos = map_start >> osb->s_clustersize_bits;
mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
map_start + map_len);
mapping_end -= cpos;
is_last = 0;
while (cpos < mapping_end && !is_last) {
u32 fe_flags;
ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
&hole_size, &rec, &is_last);
if (ret) {
mlog_errno(ret);
goto out;
}
if (rec.e_blkno == 0ULL) {
cpos += hole_size;
continue;
}
fe_flags = 0;
if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
fe_flags |= FIEMAP_EXTENT_SHARED;
if (is_last)
fe_flags |= FIEMAP_EXTENT_LAST;
len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
len_bytes, fe_flags);
if (ret)
break;
cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
}
if (ret > 0)
ret = 0;
out_unlock:
brelse(di_bh);
up_read(&OCFS2_I(inode)->ip_alloc_sem);
ocfs2_inode_unlock(inode, 0);
out:
return ret;
}
int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
{
struct inode *inode = file->f_mapping->host;
int ret;
unsigned int is_last = 0, is_data = 0;
u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
u32 cpos, cend, clen, hole_size;
u64 extoff, extlen;
struct buffer_head *di_bh = NULL;
struct ocfs2_extent_rec rec;
BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);
ret = ocfs2_inode_lock(inode, &di_bh, 0);
if (ret) {
mlog_errno(ret);
goto out;
}
down_read(&OCFS2_I(inode)->ip_alloc_sem);
if (*offset >= inode->i_size) {
ret = -ENXIO;
goto out_unlock;
}
if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
if (whence == SEEK_HOLE)
*offset = inode->i_size;
goto out_unlock;
}
clen = 0;
cpos = *offset >> cs_bits;
cend = ocfs2_clusters_for_bytes(inode->i_sb, inode->i_size);
while (cpos < cend && !is_last) {
ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
&rec, &is_last);
if (ret) {
mlog_errno(ret);
goto out_unlock;
}
extoff = cpos;
extoff <<= cs_bits;
if (rec.e_blkno == 0ULL) {
clen = hole_size;
is_data = 0;
} else {
clen = le16_to_cpu(rec.e_leaf_clusters) -
(cpos - le32_to_cpu(rec.e_cpos));
is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ? 0 : 1;
}
if ((!is_data && whence == SEEK_HOLE) ||
(is_data && whence == SEEK_DATA)) {
if (extoff > *offset)
*offset = extoff;
goto out_unlock;
}
if (!is_last)
cpos += clen;
}
if (whence == SEEK_HOLE) {
extoff = cpos;
extoff <<= cs_bits;
extlen = clen;
extlen <<= cs_bits;
if ((extoff + extlen) > inode->i_size)
extlen = inode->i_size - extoff;
extoff += extlen;
if (extoff > *offset)
*offset = extoff;
goto out_unlock;
}
ret = -ENXIO;
out_unlock:
brelse(di_bh);
up_read(&OCFS2_I(inode)->ip_alloc_sem);
ocfs2_inode_unlock(inode, 0);
out:
return ret;
}
int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
struct buffer_head *bhs[], int flags,
int (*validate)(struct super_block *sb,
struct buffer_head *bh))
{
int rc = 0;
u64 p_block, p_count;
int i, count, done = 0;
trace_ocfs2_read_virt_blocks(
inode, (unsigned long long)v_block, nr, bhs, flags,
validate);
if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
i_size_read(inode)) {
BUG_ON(!(flags & OCFS2_BH_READAHEAD));
goto out;
}
while (done < nr) {
down_read(&OCFS2_I(inode)->ip_alloc_sem);
rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
&p_block, &p_count, NULL);
up_read(&OCFS2_I(inode)->ip_alloc_sem);
if (rc) {
mlog_errno(rc);
break;
}
if (!p_block) {
rc = -EIO;
mlog(ML_ERROR,
"Inode #%llu contains a hole at offset %llu\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno,
(unsigned long long)(v_block + done) <<
inode->i_sb->s_blocksize_bits);
break;
}
count = nr - done;
if (p_count < count)
count = p_count;
/*
* If the caller passed us bhs, they should have come
* from a previous readahead call to this function. Thus,
* they should have the right b_blocknr.
*/
for (i = 0; i < count; i++) {
if (!bhs[done + i])
continue;
BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
}
rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
bhs + done, flags, validate);
if (rc) {
mlog_errno(rc);
break;
}
done += count;
}
out:
return rc;
}