/*
* recovery.c - NILFS recovery logic
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Written by Ryusuke Konishi <ryusuke@osrg.net>
*/
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/crc32.h>
#include "nilfs.h"
#include "segment.h"
#include "sufile.h"
#include "page.h"
#include "segbuf.h"
/*
* Segment check result
*/
enum {
NILFS_SEG_VALID,
NILFS_SEG_NO_SUPER_ROOT,
NILFS_SEG_FAIL_IO,
NILFS_SEG_FAIL_MAGIC,
NILFS_SEG_FAIL_SEQ,
NILFS_SEG_FAIL_CHECKSUM_SEGSUM,
NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT,
NILFS_SEG_FAIL_CHECKSUM_FULL,
NILFS_SEG_FAIL_CONSISTENCY,
};
/* work structure for recovery */
struct nilfs_recovery_block {
ino_t ino; /* Inode number of the file that this block
belongs to */
sector_t blocknr; /* block number */
__u64 vblocknr; /* virtual block number */
unsigned long blkoff; /* File offset of the data block (per block) */
struct list_head list;
};
static int nilfs_warn_segment_error(int err)
{
switch (err) {
case NILFS_SEG_FAIL_IO:
printk(KERN_WARNING
"NILFS warning: I/O error on loading last segment\n");
return -EIO;
case NILFS_SEG_FAIL_MAGIC:
printk(KERN_WARNING
"NILFS warning: Segment magic number invalid\n");
break;
case NILFS_SEG_FAIL_SEQ:
printk(KERN_WARNING
"NILFS warning: Sequence number mismatch\n");
break;
case NILFS_SEG_FAIL_CHECKSUM_SEGSUM:
printk(KERN_WARNING
"NILFS warning: Checksum error in segment summary\n");
break;
case NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT:
printk(KERN_WARNING
"NILFS warning: Checksum error in super root\n");
break;
case NILFS_SEG_FAIL_CHECKSUM_FULL:
printk(KERN_WARNING
"NILFS warning: Checksum error in segment payload\n");
break;
case NILFS_SEG_FAIL_CONSISTENCY:
printk(KERN_WARNING
"NILFS warning: Inconsistent segment\n");
break;
case NILFS_SEG_NO_SUPER_ROOT:
printk(KERN_WARNING
"NILFS warning: No super root in the last segment\n");
break;
}
return -EINVAL;
}
static void store_segsum_info(struct nilfs_segsum_info *ssi,
struct nilfs_segment_summary *sum,
unsigned int blocksize)
{
ssi->flags = le16_to_cpu(sum->ss_flags);
ssi->seg_seq = le64_to_cpu(sum->ss_seq);
ssi->ctime = le64_to_cpu(sum->ss_create);
ssi->next = le64_to_cpu(sum->ss_next);
ssi->nblocks = le32_to_cpu(sum->ss_nblocks);
ssi->nfinfo = le32_to_cpu(sum->ss_nfinfo);
ssi->sumbytes = le32_to_cpu(sum->ss_sumbytes);
ssi->nsumblk = DIV_ROUND_UP(ssi->sumbytes, blocksize);
ssi->nfileblk = ssi->nblocks - ssi->nsumblk - !!NILFS_SEG_HAS_SR(ssi);
}
/**
* calc_crc_cont - check CRC of blocks continuously
* @sbi: nilfs_sb_info
* @bhs: buffer head of start block
* @sum: place to store result
* @offset: offset bytes in the first block
* @check_bytes: number of bytes to be checked
* @start: DBN of start block
* @nblock: number of blocks to be checked
*/
static int calc_crc_cont(struct nilfs_sb_info *sbi, struct buffer_head *bhs,
u32 *sum, unsigned long offset, u64 check_bytes,
sector_t start, unsigned long nblock)
{
unsigned long blocksize = sbi->s_super->s_blocksize;
unsigned long size;
u32 crc;
BUG_ON(offset >= blocksize);
check_bytes -= offset;
size = min_t(u64, check_bytes, blocksize - offset);
crc = crc32_le(sbi->s_nilfs->ns_crc_seed,
(unsigned char *)bhs->b_data + offset, size);
if (--nblock > 0) {
do {
struct buffer_head *bh
= sb_bread(sbi->s_super, ++start);
if (!bh)
return -EIO;
check_bytes -= size;
size = min_t(u64, check_bytes, blocksize);
crc = crc32_le(crc, bh->b_data, size);
brelse(bh);
} while (--nblock > 0);
}
*sum = crc;
return 0;
}
/**
* nilfs_read_super_root_block - read super root block
* @sb: super_block
* @sr_block: disk block number of the super root block
* @pbh: address of a buffer_head pointer to return super root buffer
* @check: CRC check flag
*/
int nilfs_read_super_root_block(struct super_block *sb, sector_t sr_block,
struct buffer_head **pbh, int check)
{
struct buffer_head *bh_sr;
struct nilfs_super_root *sr;
u32 crc;
int ret;
*pbh = NULL;
bh_sr = sb_bread(sb, sr_block);
if (unlikely(!bh_sr)) {
ret = NILFS_SEG_FAIL_IO;
goto failed;
}
sr = (struct nilfs_super_root *)bh_sr->b_data;
if (check) {
unsigned bytes = le16_to_cpu(sr->sr_bytes);
if (bytes == 0 || bytes > sb->s_blocksize) {
ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
goto failed_bh;
}
if (calc_crc_cont(NILFS_SB(sb), bh_sr, &crc,
sizeof(sr->sr_sum), bytes, sr_block, 1)) {
ret = NILFS_SEG_FAIL_IO;
goto failed_bh;
}
if (crc != le32_to_cpu(sr->sr_sum)) {
ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
goto failed_bh;
}
}
*pbh = bh_sr;
return 0;
failed_bh:
brelse(bh_sr);
failed:
return nilfs_warn_segment_error(ret);
}
/**
* load_segment_summary - read segment summary of the specified partial segment
* @sbi: nilfs_sb_info
* @pseg_start: start disk block number of partial segment
* @seg_seq: sequence number requested
* @ssi: pointer to nilfs_segsum_info struct to store information
* @full_check: full check flag
* (0: only checks segment summary CRC, 1: data CRC)
*/
static int
load_segment_summary(struct nilfs_sb_info *sbi, sector_t pseg_start,
u64 seg_seq, struct nilfs_segsum_info *ssi,
int full_check)
{
struct buffer_head *bh_sum;
struct nilfs_segment_summary *sum;
unsigned long offset, nblock;
u64 check_bytes;
u32 crc, crc_sum;
int ret = NILFS_SEG_FAIL_IO;
bh_sum = sb_bread(sbi->s_super, pseg_start);
if (!bh_sum)
goto out;
sum = (struct nilfs_segment_summary *)bh_sum->b_data;
/* Check consistency of segment summary */
if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC) {
ret = NILFS_SEG_FAIL_MAGIC;
goto failed;
}
store_segsum_info(ssi, sum, sbi->s_super->s_blocksize);
if (seg_seq != ssi->seg_seq) {
ret = NILFS_SEG_FAIL_SEQ;
goto failed;
}
if (full_check) {
offset = sizeof(sum->ss_datasum);
check_bytes =
((u64)ssi->nblocks << sbi->s_super->s_blocksize_bits);
nblock = ssi->nblocks;
crc_sum = le32_to_cpu(sum->ss_datasum);
ret = NILFS_SEG_FAIL_CHECKSUM_FULL;
} else { /* only checks segment summary */
offset = sizeof(sum->ss_datasum) + sizeof(sum->ss_sumsum);
check_bytes = ssi->sumbytes;
nblock = ssi->nsumblk;
crc_sum = le32_to_cpu(sum->ss_sumsum);
ret = NILFS_SEG_FAIL_CHECKSUM_SEGSUM;
}
if (unlikely(nblock == 0 ||
nblock > sbi->s_nilfs->ns_blocks_per_segment)) {
/* This limits the number of blocks read in the CRC check */
ret = NILFS_SEG_FAIL_CONSISTENCY;
goto failed;
}
if (calc_crc_cont(sbi, bh_sum, &crc, offset, check_bytes,
pseg_start, nblock)) {
ret = NILFS_SEG_FAIL_IO;
goto failed;
}
if (crc == crc_sum)
ret = 0;
failed:
brelse(bh_sum);
out:
return ret;
}
static void *segsum_get(struct super_block *sb, struct buffer_head **pbh,
unsigned int *offset, unsigned int bytes)
{
void *ptr;
sector_t blocknr;
BUG_ON((*pbh)->b_size < *offset);
if (bytes > (*pbh)->b_size - *offset) {
blocknr = (*pbh)->b_blocknr;
brelse(*pbh);
*pbh = sb_bread(sb, blocknr + 1);
if (unlikely(!*pbh))
return NULL;
*offset = 0;
}
ptr = (*pbh)->b_data + *offset;
*offset += bytes;
return ptr;
}
static void segsum_skip(struct super_block *sb, struct buffer_head **pbh,
unsigned int *offset, unsigned int bytes,
unsigned long count)
{
unsigned int rest_item_in_current_block
= ((*pbh)->b_size - *offset) / bytes;
if (count <= rest_item_in_current_block) {
*offset += bytes * count;
} else {
sector_t blocknr = (*pbh)->b_blocknr;
unsigned int nitem_per_block = (*pbh)->b_size / bytes;
unsigned int bcnt;
count -= rest_item_in_current_block;
bcnt = DIV_ROUND_UP(count, nitem_per_block);
*offset = bytes * (count - (bcnt - 1) * nitem_per_block);
brelse(*pbh);
*pbh = sb_bread(sb, blocknr + bcnt);
}
}
static int
collect_blocks_from_segsum(struct nilfs_sb_info *sbi, sector_t sum_blocknr,
struct nilfs_segsum_info *ssi,
struct list_head *head)
{
struct buffer_head *bh;
unsigned int offset;
unsigned long nfinfo = ssi->nfinfo;
sector_t blocknr = sum_blocknr + ssi->nsumblk;
ino_t ino;
int err = -EIO;
if (!nfinfo)
return 0;
bh = sb_bread(sbi->s_super, sum_blocknr);
if (unlikely(!bh))
goto out;
offset = le16_to_cpu(
((struct nilfs_segment_summary *)bh->b_data)->ss_bytes);
for (;;) {
unsigned long nblocks, ndatablk, nnodeblk;
struct nilfs_finfo *finfo;
finfo = segsum_get(sbi->s_super, &bh, &offset, sizeof(*finfo));
if (unlikely(!finfo))
goto out;
ino = le64_to_cpu(finfo->fi_ino);
nblocks = le32_to_cpu(finfo->fi_nblocks);
ndatablk = le32_to_cpu(finfo->fi_ndatablk);
nnodeblk = nblocks - ndatablk;
while (ndatablk-- > 0) {
struct nilfs_recovery_block *rb;
struct nilfs_binfo_v *binfo;
binfo = segsum_get(sbi->s_super, &bh, &offset,
sizeof(*binfo));
if (unlikely(!binfo))
goto out;
rb = kmalloc(sizeof(*rb), GFP_NOFS);
if (unlikely(!rb)) {
err = -ENOMEM;
goto out;
}
rb->ino = ino;
rb->blocknr = blocknr++;
rb->vblocknr = le64_to_cpu(binfo->bi_vblocknr);
rb->blkoff = le64_to_cpu(binfo->bi_blkoff);
/* INIT_LIST_HEAD(&rb->list); */
list_add_tail(&rb->list, head);
}
if (--nfinfo == 0)
break;
blocknr += nnodeblk; /* always 0 for the data sync segments */
segsum_skip(sbi->s_super, &bh, &offset, sizeof(__le64),
nnodeblk);
if (unlikely(!bh))
goto out;
}
err = 0;
out:
brelse(bh); /* brelse(NULL) is just ignored */
return err;
}
static void dispose_recovery_list(struct list_head *head)
{
while (!list_empty(head)) {
struct nilfs_recovery_block *rb
= list_entry(head->next,
struct nilfs_recovery_block, list);
list_del(&rb->list);
kfree(rb);
}
}
struct nilfs_segment_entry {
struct list_head list;
__u64 segnum;
};
static int nilfs_segment_list_add(struct list_head *head, __u64 segnum)
{
struct nilfs_segment_entry *ent = kmalloc(sizeof(*ent), GFP_NOFS);
if (unlikely(!ent))
return -ENOMEM;
ent->segnum = segnum;
INIT_LIST_HEAD(&ent->list);
list_add_tail(&ent->list, head);
return 0;
}
void nilfs_dispose_segment_list(struct list_head *head)
{
while (!list_empty(head)) {
struct nilfs_segment_entry *ent
= list_entry(head->next,
struct nilfs_segment_entry, list);
list_del(&ent->list);
kfree(ent);
}
}
static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
struct nilfs_sb_info *sbi,
struct nilfs_recovery_info *ri)
{
struct list_head *head = &ri->ri_used_segments;
struct nilfs_segment_entry *ent, *n;
struct inode *sufile = nilfs->ns_sufile;
__u64 segnum[4];
int err;
int i;
segnum[0] = nilfs->ns_segnum;
segnum[1] = nilfs->ns_nextnum;
segnum[2] = ri->ri_segnum;
segnum[3] = ri->ri_nextnum;
nilfs_attach_writer(nilfs, sbi);
/*
* Releasing the next segment of the latest super root.
* The next segment is invalidated by this recovery.
*/
err = nilfs_sufile_free(sufile, segnum[1]);
if (unlikely(err))
goto failed;
for (i = 1; i < 4; i++) {
err = nilfs_segment_list_add(head, segnum[i]);
if (unlikely(err))
goto failed;
}
/*
* Collecting segments written after the latest super root.
* These are marked dirty to avoid being reallocated in the next write.
*/
list_for_each_entry_safe(ent, n, head, list) {
if (ent->segnum != segnum[0]) {
err = nilfs_sufile_scrap(sufile, ent->segnum);
if (unlikely(err))
goto failed;
}
list_del(&ent->list);
kfree(ent);
}
/* Allocate new segments for recovery */
err = nilfs_sufile_alloc(sufile, &segnum[0]);
if (unlikely(err))
goto failed;
nilfs->ns_pseg_offset = 0;
nilfs->ns_seg_seq = ri->ri_seq + 2;
nilfs->ns_nextnum = nilfs->ns_segnum = segnum[0];
failed:
/* No need to recover sufile because it will be destroyed on error */
nilfs_detach_writer(nilfs, sbi);
return err;
}
static int nilfs_recovery_copy_block(struct nilfs_sb_info *sbi,
struct nilfs_recovery_block *rb,
struct page *page)
{
struct buffer_head *bh_org;
void *kaddr;
bh_org = sb_bread(sbi->s_super, rb->blocknr);
if (unlikely(!bh_org))
return -EIO;
kaddr = kmap_atomic(page, KM_USER0);
memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size);
kunmap_atomic(kaddr, KM_USER0);
brelse(bh_org);
return 0;
}
static int recover_dsync_blocks(struct nilfs_sb_info *sbi,
struct list_head *head,
unsigned long *nr_salvaged_blocks)
{
struct inode *inode;
struct nilfs_recovery_block *rb, *n;
unsigned blocksize = sbi->s_super->s_blocksize;
struct page *page;
loff_t pos;
int err = 0, err2 = 0;
list_for_each_entry_safe(rb, n, head, list) {
inode = nilfs_iget(sbi->s_super, rb->ino);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
inode = NULL;
goto failed_inode;
}
pos = rb->blkoff << inode->i_blkbits;
page = NULL;
err = block_write_begin(NULL, inode->i_mapping, pos, blocksize,
0, &page, NULL, nilfs_get_block);
if (unlikely(err))
goto failed_inode;
err = nilfs_recovery_copy_block(sbi, rb, page);
if (unlikely(err))
goto failed_page;
err = nilfs_set_file_dirty(sbi, inode, 1);
if (unlikely(err))
goto failed_page;
block_write_end(NULL, inode->i_mapping, pos, blocksize,
blocksize, page, NULL);
unlock_page(page);
page_cache_release(page);
(*nr_salvaged_blocks)++;
goto next;
failed_page:
unlock_page(page);
page_cache_release(page);
failed_inode:
printk(KERN_WARNING
"NILFS warning: error recovering data block "
"(err=%d, ino=%lu, block-offset=%llu)\n",
err, (unsigned long)rb->ino,
(unsigned long long)rb->blkoff);
if (!err2)
err2 = err;
next:
iput(inode); /* iput(NULL) is just ignored */
list_del_init(&rb->list);
kfree(rb);
}
return err2;
}
/**
* nilfs_do_roll_forward - salvage logical segments newer than the latest
* checkpoint
* @sbi: nilfs_sb_info
* @nilfs: the_nilfs
* @ri: pointer to a nilfs_recovery_info
*/
static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
struct nilfs_sb_info *sbi,
struct nilfs_recovery_info *ri)
{
struct nilfs_segsum_info ssi;
sector_t pseg_start;
sector_t seg_start, seg_end; /* Starting/ending DBN of full segment */
unsigned long nsalvaged_blocks = 0;
u64 seg_seq;
__u64 segnum, nextnum = 0;
int empty_seg = 0;
int err = 0, ret;
LIST_HEAD(dsync_blocks); /* list of data blocks to be recovered */
enum {
RF_INIT_ST,
RF_DSYNC_ST, /* scanning data-sync segments */
};
int state = RF_INIT_ST;
nilfs_attach_writer(nilfs, sbi);
pseg_start = ri->ri_lsegs_start;
seg_seq = ri->ri_lsegs_start_seq;
segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
while (segnum != ri->ri_segnum || pseg_start <= ri->ri_pseg_start) {
ret = load_segment_summary(sbi, pseg_start, seg_seq, &ssi, 1);
if (ret) {
if (ret == NILFS_SEG_FAIL_IO) {
err = -EIO;
goto failed;
}
goto strayed;
}
if (unlikely(NILFS_SEG_HAS_SR(&ssi)))
goto confused;
/* Found a valid partial segment; do recovery actions */
nextnum = nilfs_get_segnum_of_block(nilfs, ssi.next);
empty_seg = 0;
nilfs->ns_ctime = ssi.ctime;
if (!(ssi.flags & NILFS_SS_GC))
nilfs->ns_nongc_ctime = ssi.ctime;
switch (state) {
case RF_INIT_ST:
if (!NILFS_SEG_LOGBGN(&ssi) || !NILFS_SEG_DSYNC(&ssi))
goto try_next_pseg;
state = RF_DSYNC_ST;
/* Fall through */
case RF_DSYNC_ST:
if (!NILFS_SEG_DSYNC(&ssi))
goto confused;
err = collect_blocks_from_segsum(
sbi, pseg_start, &ssi, &dsync_blocks);
if (unlikely(err))
goto failed;
if (NILFS_SEG_LOGEND(&ssi)) {
err = recover_dsync_blocks(
sbi, &dsync_blocks, &nsalvaged_blocks);
if (unlikely(err))
goto failed;
state = RF_INIT_ST;
}
break; /* Fall through to try_next_pseg */
}
try_next_pseg:
if (pseg_start == ri->ri_lsegs_end)
break;
pseg_start += ssi.nblocks;
if (pseg_start < seg_end)
continue;
goto feed_segment;
strayed:
if (pseg_start == ri->ri_lsegs_end)
break;
feed_segment:
/* Looking to the next full segment */
if (empty_seg++)
break;
seg_seq++;
segnum = nextnum;
nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
pseg_start = seg_start;
}
if (nsalvaged_blocks) {
printk(KERN_INFO "NILFS (device %s): salvaged %lu blocks\n",
sbi->s_super->s_id, nsalvaged_blocks);
ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE;
}
out:
dispose_recovery_list(&dsync_blocks);
nilfs_detach_writer(sbi->s_nilfs, sbi);
return err;
confused:
err = -EINVAL;
failed:
printk(KERN_ERR
"NILFS (device %s): Error roll-forwarding "
"(err=%d, pseg block=%llu). ",
sbi->s_super->s_id, err, (unsigned long long)pseg_start);
goto out;
}
static void nilfs_finish_roll_forward(struct the_nilfs *nilfs,
struct nilfs_sb_info *sbi,
struct nilfs_recovery_info *ri)
{
struct buffer_head *bh;
int err;
if (nilfs_get_segnum_of_block(nilfs, ri->ri_lsegs_start) !=
nilfs_get_segnum_of_block(nilfs, ri->ri_super_root))
return;
bh = sb_getblk(sbi->s_super, ri->ri_lsegs_start);
BUG_ON(!bh);
memset(bh->b_data, 0, bh->b_size);
set_buffer_dirty(bh);
err = sync_dirty_buffer(bh);
if (unlikely(err))
printk(KERN_WARNING
"NILFS warning: buffer sync write failed during "
"post-cleaning of recovery.\n");
brelse(bh);
}
/**
* nilfs_recover_logical_segments - salvage logical segments written after
* the latest super root
* @nilfs: the_nilfs
* @sbi: nilfs_sb_info
* @ri: pointer to a nilfs_recovery_info struct to store search results.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error code is returned.
*
* %-EINVAL - Inconsistent filesystem state.
*
* %-EIO - I/O error
*
* %-ENOSPC - No space left on device (only in a panic state).
*
* %-ERESTARTSYS - Interrupted.
*
* %-ENOMEM - Insufficient memory available.
*/
int nilfs_recover_logical_segments(struct the_nilfs *nilfs,
struct nilfs_sb_info *sbi,
struct nilfs_recovery_info *ri)
{
int err;
if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0)
return 0;
err = nilfs_attach_checkpoint(sbi, ri->ri_cno);
if (unlikely(err)) {
printk(KERN_ERR
"NILFS: error loading the latest checkpoint.\n");
return err;
}
err = nilfs_do_roll_forward(nilfs, sbi, ri);
if (unlikely(err))
goto failed;
if (ri->ri_need_recovery == NILFS_RECOVERY_ROLLFORWARD_DONE) {
err = nilfs_prepare_segment_for_recovery(nilfs, sbi, ri);
if (unlikely(err)) {
printk(KERN_ERR "NILFS: Error preparing segments for "
"recovery.\n");
goto failed;
}
err = nilfs_attach_segment_constructor(sbi);
if (unlikely(err))
goto failed;
set_nilfs_discontinued(nilfs);
err = nilfs_construct_segment(sbi->s_super);
nilfs_detach_segment_constructor(sbi);
if (unlikely(err)) {
printk(KERN_ERR "NILFS: Oops! recovery failed. "
"(err=%d)\n", err);
goto failed;
}
nilfs_finish_roll_forward(nilfs, sbi, ri);
}
failed:
nilfs_detach_checkpoint(sbi);
return err;
}
/**
* nilfs_search_super_root - search the latest valid super root
* @nilfs: the_nilfs
* @sbi: nilfs_sb_info
* @ri: pointer to a nilfs_recovery_info struct to store search results.
*
* nilfs_search_super_root() looks for the latest super-root from a partial
* segment pointed by the superblock. It sets up struct the_nilfs through
* this search. It fills nilfs_recovery_info (ri) required for recovery.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error code is returned.
*
* %-EINVAL - No valid segment found
*
* %-EIO - I/O error
*/
int nilfs_search_super_root(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi,
struct nilfs_recovery_info *ri)
{
struct nilfs_segsum_info ssi;
sector_t pseg_start, pseg_end, sr_pseg_start = 0;
sector_t seg_start, seg_end; /* range of full segment (block number) */
sector_t b, end;
u64 seg_seq;
__u64 segnum, nextnum = 0;
__u64 cno;
LIST_HEAD(segments);
int empty_seg = 0, scan_newer = 0;
int ret;
pseg_start = nilfs->ns_last_pseg;
seg_seq = nilfs->ns_last_seq;
cno = nilfs->ns_last_cno;
segnum = nilfs_get_segnum_of_block(nilfs, pseg_start);
/* Calculate range of segment */
nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
/* Read ahead segment */
b = seg_start;
while (b <= seg_end)
sb_breadahead(sbi->s_super, b++);
for (;;) {
/* Load segment summary */
ret = load_segment_summary(sbi, pseg_start, seg_seq, &ssi, 1);
if (ret) {
if (ret == NILFS_SEG_FAIL_IO)
goto failed;
goto strayed;
}
pseg_end = pseg_start + ssi.nblocks - 1;
if (unlikely(pseg_end > seg_end)) {
ret = NILFS_SEG_FAIL_CONSISTENCY;
goto strayed;
}
/* A valid partial segment */
ri->ri_pseg_start = pseg_start;
ri->ri_seq = seg_seq;
ri->ri_segnum = segnum;
nextnum = nilfs_get_segnum_of_block(nilfs, ssi.next);
ri->ri_nextnum = nextnum;
empty_seg = 0;
if (!NILFS_SEG_HAS_SR(&ssi) && !scan_newer) {
/* This will never happen because a superblock
(last_segment) always points to a pseg
having a super root. */
ret = NILFS_SEG_FAIL_CONSISTENCY;
goto failed;
}
if (pseg_start == seg_start) {
nilfs_get_segment_range(nilfs, nextnum, &b, &end);
while (b <= end)
sb_breadahead(sbi->s_super, b++);
}
if (!NILFS_SEG_HAS_SR(&ssi)) {
if (!ri->ri_lsegs_start && NILFS_SEG_LOGBGN(&ssi)) {
ri->ri_lsegs_start = pseg_start;
ri->ri_lsegs_start_seq = seg_seq;
}
if (NILFS_SEG_LOGEND(&ssi))
ri->ri_lsegs_end = pseg_start;
goto try_next_pseg;
}
/* A valid super root was found. */
ri->ri_cno = cno++;
ri->ri_super_root = pseg_end;
ri->ri_lsegs_start = ri->ri_lsegs_end = 0;
nilfs_dispose_segment_list(&segments);
nilfs->ns_pseg_offset = (sr_pseg_start = pseg_start)
+ ssi.nblocks - seg_start;
nilfs->ns_seg_seq = seg_seq;
nilfs->ns_segnum = segnum;
nilfs->ns_cno = cno; /* nilfs->ns_cno = ri->ri_cno + 1 */
nilfs->ns_ctime = ssi.ctime;
nilfs->ns_nextnum = nextnum;
if (scan_newer)
ri->ri_need_recovery = NILFS_RECOVERY_SR_UPDATED;
else {
if (nilfs->ns_mount_state & NILFS_VALID_FS)
goto super_root_found;
scan_newer = 1;
}
/* reset region for roll-forward */
pseg_start += ssi.nblocks;
if (pseg_start < seg_end)
continue;
goto feed_segment;
try_next_pseg:
/* Standing on a course, or met an inconsistent state */
pseg_start += ssi.nblocks;
if (pseg_start < seg_end)
continue;
goto feed_segment;
strayed:
/* Off the trail */
if (!scan_newer)
/*
* This can happen if a checkpoint was written without
* barriers, or as a result of an I/O failure.
*/
goto failed;
feed_segment:
/* Looking to the next full segment */
if (empty_seg++)
goto super_root_found; /* found a valid super root */
ret = nilfs_segment_list_add(&segments, segnum);
if (unlikely(ret))
goto failed;
seg_seq++;
segnum = nextnum;
nilfs_get_segment_range(nilfs, segnum, &seg_start, &seg_end);
pseg_start = seg_start;
}
super_root_found:
/* Updating pointers relating to the latest checkpoint */
list_splice(&segments, ri->ri_used_segments.prev);
nilfs->ns_last_pseg = sr_pseg_start;
nilfs->ns_last_seq = nilfs->ns_seg_seq;
nilfs->ns_last_cno = ri->ri_cno;
return 0;
failed:
nilfs_dispose_segment_list(&segments);
return (ret < 0) ? ret : nilfs_warn_segment_error(ret);
}
