linux/fs/nilfs2/recovery.c
Ryusuke Konishi ae98043f5f nilfs2: convert to SPDX license tags
Remove the verbose license text from NILFS2 files and replace them with
SPDX tags.  This does not change the license of any of the code.

Link: http://lkml.kernel.org/r/1535624528-5982-1-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-09-04 16:45:02 -07:00

955 lines
24 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* recovery.c - NILFS recovery logic
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* Written by Ryusuke Konishi.
*/
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/slab.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_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(struct super_block *sb, int err)
{
const char *msg = NULL;
switch (err) {
case NILFS_SEG_FAIL_IO:
nilfs_msg(sb, KERN_ERR, "I/O error reading segment");
return -EIO;
case NILFS_SEG_FAIL_MAGIC:
msg = "Magic number mismatch";
break;
case NILFS_SEG_FAIL_SEQ:
msg = "Sequence number mismatch";
break;
case NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT:
msg = "Checksum error in super root";
break;
case NILFS_SEG_FAIL_CHECKSUM_FULL:
msg = "Checksum error in segment payload";
break;
case NILFS_SEG_FAIL_CONSISTENCY:
msg = "Inconsistency found";
break;
case NILFS_SEG_NO_SUPER_ROOT:
msg = "No super root in the last segment";
break;
default:
nilfs_msg(sb, KERN_ERR, "unrecognized segment error %d", err);
return -EINVAL;
}
nilfs_msg(sb, KERN_WARNING, "invalid segment: %s", msg);
return -EINVAL;
}
/**
* nilfs_compute_checksum - compute checksum of blocks continuously
* @nilfs: nilfs object
* @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 nilfs_compute_checksum(struct the_nilfs *nilfs,
struct buffer_head *bhs, u32 *sum,
unsigned long offset, u64 check_bytes,
sector_t start, unsigned long nblock)
{
unsigned int blocksize = nilfs->ns_blocksize;
unsigned long size;
u32 crc;
BUG_ON(offset >= blocksize);
check_bytes -= offset;
size = min_t(u64, check_bytes, blocksize - offset);
crc = crc32_le(nilfs->ns_crc_seed,
(unsigned char *)bhs->b_data + offset, size);
if (--nblock > 0) {
do {
struct buffer_head *bh;
bh = __bread(nilfs->ns_bdev, ++start, blocksize);
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
* @nilfs: nilfs object
* @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 the_nilfs *nilfs, 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 = __bread(nilfs->ns_bdev, sr_block, nilfs->ns_blocksize);
if (unlikely(!bh_sr)) {
ret = NILFS_SEG_FAIL_IO;
goto failed;
}
sr = (struct nilfs_super_root *)bh_sr->b_data;
if (check) {
unsigned int bytes = le16_to_cpu(sr->sr_bytes);
if (bytes == 0 || bytes > nilfs->ns_blocksize) {
ret = NILFS_SEG_FAIL_CHECKSUM_SUPER_ROOT;
goto failed_bh;
}
if (nilfs_compute_checksum(
nilfs, 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(nilfs->ns_sb, ret);
}
/**
* nilfs_read_log_header - read summary header of the specified log
* @nilfs: nilfs object
* @start_blocknr: start block number of the log
* @sum: pointer to return segment summary structure
*/
static struct buffer_head *
nilfs_read_log_header(struct the_nilfs *nilfs, sector_t start_blocknr,
struct nilfs_segment_summary **sum)
{
struct buffer_head *bh_sum;
bh_sum = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
if (bh_sum)
*sum = (struct nilfs_segment_summary *)bh_sum->b_data;
return bh_sum;
}
/**
* nilfs_validate_log - verify consistency of log
* @nilfs: nilfs object
* @seg_seq: sequence number of segment
* @bh_sum: buffer head of summary block
* @sum: segment summary struct
*/
static int nilfs_validate_log(struct the_nilfs *nilfs, u64 seg_seq,
struct buffer_head *bh_sum,
struct nilfs_segment_summary *sum)
{
unsigned long nblock;
u32 crc;
int ret;
ret = NILFS_SEG_FAIL_MAGIC;
if (le32_to_cpu(sum->ss_magic) != NILFS_SEGSUM_MAGIC)
goto out;
ret = NILFS_SEG_FAIL_SEQ;
if (le64_to_cpu(sum->ss_seq) != seg_seq)
goto out;
nblock = le32_to_cpu(sum->ss_nblocks);
ret = NILFS_SEG_FAIL_CONSISTENCY;
if (unlikely(nblock == 0 || nblock > nilfs->ns_blocks_per_segment))
/* This limits the number of blocks read in the CRC check */
goto out;
ret = NILFS_SEG_FAIL_IO;
if (nilfs_compute_checksum(nilfs, bh_sum, &crc, sizeof(sum->ss_datasum),
((u64)nblock << nilfs->ns_blocksize_bits),
bh_sum->b_blocknr, nblock))
goto out;
ret = NILFS_SEG_FAIL_CHECKSUM_FULL;
if (crc != le32_to_cpu(sum->ss_datasum))
goto out;
ret = 0;
out:
return ret;
}
/**
* nilfs_read_summary_info - read an item on summary blocks of a log
* @nilfs: nilfs object
* @pbh: the current buffer head on summary blocks [in, out]
* @offset: the current byte offset on summary blocks [in, out]
* @bytes: byte size of the item to be read
*/
static void *nilfs_read_summary_info(struct the_nilfs *nilfs,
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 = __bread(nilfs->ns_bdev, blocknr + 1,
nilfs->ns_blocksize);
if (unlikely(!*pbh))
return NULL;
*offset = 0;
}
ptr = (*pbh)->b_data + *offset;
*offset += bytes;
return ptr;
}
/**
* nilfs_skip_summary_info - skip items on summary blocks of a log
* @nilfs: nilfs object
* @pbh: the current buffer head on summary blocks [in, out]
* @offset: the current byte offset on summary blocks [in, out]
* @bytes: byte size of the item to be skipped
* @count: number of items to be skipped
*/
static void nilfs_skip_summary_info(struct the_nilfs *nilfs,
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 = __bread(nilfs->ns_bdev, blocknr + bcnt,
nilfs->ns_blocksize);
}
}
/**
* nilfs_scan_dsync_log - get block information of a log written for data sync
* @nilfs: nilfs object
* @start_blocknr: start block number of the log
* @sum: log summary information
* @head: list head to add nilfs_recovery_block struct
*/
static int nilfs_scan_dsync_log(struct the_nilfs *nilfs, sector_t start_blocknr,
struct nilfs_segment_summary *sum,
struct list_head *head)
{
struct buffer_head *bh;
unsigned int offset;
u32 nfinfo, sumbytes;
sector_t blocknr;
ino_t ino;
int err = -EIO;
nfinfo = le32_to_cpu(sum->ss_nfinfo);
if (!nfinfo)
return 0;
sumbytes = le32_to_cpu(sum->ss_sumbytes);
blocknr = start_blocknr + DIV_ROUND_UP(sumbytes, nilfs->ns_blocksize);
bh = __bread(nilfs->ns_bdev, start_blocknr, nilfs->ns_blocksize);
if (unlikely(!bh))
goto out;
offset = le16_to_cpu(sum->ss_bytes);
for (;;) {
unsigned long nblocks, ndatablk, nnodeblk;
struct nilfs_finfo *finfo;
finfo = nilfs_read_summary_info(nilfs, &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 = nilfs_read_summary_info(nilfs, &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 data sync logs */
nilfs_skip_summary_info(nilfs, &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;
rb = list_first_entry(head, 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;
ent = list_first_entry(head, struct nilfs_segment_entry, list);
list_del(&ent->list);
kfree(ent);
}
}
static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
struct super_block *sb,
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;
/*
* 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 */
return err;
}
static int nilfs_recovery_copy_block(struct the_nilfs *nilfs,
struct nilfs_recovery_block *rb,
struct page *page)
{
struct buffer_head *bh_org;
void *kaddr;
bh_org = __bread(nilfs->ns_bdev, rb->blocknr, nilfs->ns_blocksize);
if (unlikely(!bh_org))
return -EIO;
kaddr = kmap_atomic(page);
memcpy(kaddr + bh_offset(bh_org), bh_org->b_data, bh_org->b_size);
kunmap_atomic(kaddr);
brelse(bh_org);
return 0;
}
static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
struct super_block *sb,
struct nilfs_root *root,
struct list_head *head,
unsigned long *nr_salvaged_blocks)
{
struct inode *inode;
struct nilfs_recovery_block *rb, *n;
unsigned int blocksize = nilfs->ns_blocksize;
struct page *page;
loff_t pos;
int err = 0, err2 = 0;
list_for_each_entry_safe(rb, n, head, list) {
inode = nilfs_iget(sb, root, rb->ino);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
inode = NULL;
goto failed_inode;
}
pos = rb->blkoff << inode->i_blkbits;
err = block_write_begin(inode->i_mapping, pos, blocksize,
0, &page, nilfs_get_block);
if (unlikely(err)) {
loff_t isize = inode->i_size;
if (pos + blocksize > isize)
nilfs_write_failed(inode->i_mapping,
pos + blocksize);
goto failed_inode;
}
err = nilfs_recovery_copy_block(nilfs, rb, page);
if (unlikely(err))
goto failed_page;
err = nilfs_set_file_dirty(inode, 1);
if (unlikely(err))
goto failed_page;
block_write_end(NULL, inode->i_mapping, pos, blocksize,
blocksize, page, NULL);
unlock_page(page);
put_page(page);
(*nr_salvaged_blocks)++;
goto next;
failed_page:
unlock_page(page);
put_page(page);
failed_inode:
nilfs_msg(sb, KERN_WARNING,
"error %d recovering data block (ino=%lu, block-offset=%llu)",
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
* @nilfs: nilfs object
* @sb: super block instance
* @ri: pointer to a nilfs_recovery_info
*/
static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
struct super_block *sb,
struct nilfs_root *root,
struct nilfs_recovery_info *ri)
{
struct buffer_head *bh_sum = NULL;
struct nilfs_segment_summary *sum = NULL;
sector_t pseg_start;
sector_t seg_start, seg_end; /* Starting/ending DBN of full segment */
unsigned long nsalvaged_blocks = 0;
unsigned int flags;
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;
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) {
brelse(bh_sum);
bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
if (!bh_sum) {
err = -EIO;
goto failed;
}
ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
if (ret) {
if (ret == NILFS_SEG_FAIL_IO) {
err = -EIO;
goto failed;
}
goto strayed;
}
flags = le16_to_cpu(sum->ss_flags);
if (flags & NILFS_SS_SR)
goto confused;
/* Found a valid partial segment; do recovery actions */
nextnum = nilfs_get_segnum_of_block(nilfs,
le64_to_cpu(sum->ss_next));
empty_seg = 0;
nilfs->ns_ctime = le64_to_cpu(sum->ss_create);
if (!(flags & NILFS_SS_GC))
nilfs->ns_nongc_ctime = nilfs->ns_ctime;
switch (state) {
case RF_INIT_ST:
if (!(flags & NILFS_SS_LOGBGN) ||
!(flags & NILFS_SS_SYNDT))
goto try_next_pseg;
state = RF_DSYNC_ST;
/* Fall through */
case RF_DSYNC_ST:
if (!(flags & NILFS_SS_SYNDT))
goto confused;
err = nilfs_scan_dsync_log(nilfs, pseg_start, sum,
&dsync_blocks);
if (unlikely(err))
goto failed;
if (flags & NILFS_SS_LOGEND) {
err = nilfs_recover_dsync_blocks(
nilfs, sb, root, &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 += le32_to_cpu(sum->ss_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) {
nilfs_msg(sb, KERN_INFO, "salvaged %lu blocks",
nsalvaged_blocks);
ri->ri_need_recovery = NILFS_RECOVERY_ROLLFORWARD_DONE;
}
out:
brelse(bh_sum);
dispose_recovery_list(&dsync_blocks);
return err;
confused:
err = -EINVAL;
failed:
nilfs_msg(sb, KERN_ERR,
"error %d roll-forwarding partial segment at blocknr = %llu",
err, (unsigned long long)pseg_start);
goto out;
}
static void nilfs_finish_roll_forward(struct the_nilfs *nilfs,
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 = __getblk(nilfs->ns_bdev, ri->ri_lsegs_start, nilfs->ns_blocksize);
BUG_ON(!bh);
memset(bh->b_data, 0, bh->b_size);
set_buffer_dirty(bh);
err = sync_dirty_buffer(bh);
if (unlikely(err))
nilfs_msg(nilfs->ns_sb, KERN_WARNING,
"buffer sync write failed during post-cleaning of recovery.");
brelse(bh);
}
/**
* nilfs_salvage_orphan_logs - salvage logs written after the latest checkpoint
* @nilfs: nilfs object
* @sb: super block instance
* @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_salvage_orphan_logs(struct the_nilfs *nilfs,
struct super_block *sb,
struct nilfs_recovery_info *ri)
{
struct nilfs_root *root;
int err;
if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0)
return 0;
err = nilfs_attach_checkpoint(sb, ri->ri_cno, true, &root);
if (unlikely(err)) {
nilfs_msg(sb, KERN_ERR,
"error %d loading the latest checkpoint", err);
return err;
}
err = nilfs_do_roll_forward(nilfs, sb, root, ri);
if (unlikely(err))
goto failed;
if (ri->ri_need_recovery == NILFS_RECOVERY_ROLLFORWARD_DONE) {
err = nilfs_prepare_segment_for_recovery(nilfs, sb, ri);
if (unlikely(err)) {
nilfs_msg(sb, KERN_ERR,
"error %d preparing segment for recovery",
err);
goto failed;
}
err = nilfs_attach_log_writer(sb, root);
if (unlikely(err))
goto failed;
set_nilfs_discontinued(nilfs);
err = nilfs_construct_segment(sb);
nilfs_detach_log_writer(sb);
if (unlikely(err)) {
nilfs_msg(sb, KERN_ERR,
"error %d writing segment for recovery",
err);
goto failed;
}
nilfs_finish_roll_forward(nilfs, ri);
}
failed:
nilfs_put_root(root);
return err;
}
/**
* nilfs_search_super_root - search the latest valid super root
* @nilfs: the_nilfs
* @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
*
* %-ENOMEM - Insufficient memory available.
*/
int nilfs_search_super_root(struct the_nilfs *nilfs,
struct nilfs_recovery_info *ri)
{
struct buffer_head *bh_sum = NULL;
struct nilfs_segment_summary *sum = NULL;
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;
unsigned long nblocks;
unsigned int flags;
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)
__breadahead(nilfs->ns_bdev, b++, nilfs->ns_blocksize);
for (;;) {
brelse(bh_sum);
ret = NILFS_SEG_FAIL_IO;
bh_sum = nilfs_read_log_header(nilfs, pseg_start, &sum);
if (!bh_sum)
goto failed;
ret = nilfs_validate_log(nilfs, seg_seq, bh_sum, sum);
if (ret) {
if (ret == NILFS_SEG_FAIL_IO)
goto failed;
goto strayed;
}
nblocks = le32_to_cpu(sum->ss_nblocks);
pseg_end = pseg_start + 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,
le64_to_cpu(sum->ss_next));
ri->ri_nextnum = nextnum;
empty_seg = 0;
flags = le16_to_cpu(sum->ss_flags);
if (!(flags & NILFS_SS_SR) && !scan_newer) {
/*
* This will never happen because a superblock
* (last_segment) always points to a pseg with
* 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)
__breadahead(nilfs->ns_bdev, b++,
nilfs->ns_blocksize);
}
if (!(flags & NILFS_SS_SR)) {
if (!ri->ri_lsegs_start && (flags & NILFS_SS_LOGBGN)) {
ri->ri_lsegs_start = pseg_start;
ri->ri_lsegs_start_seq = seg_seq;
}
if (flags & NILFS_SS_LOGEND)
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);
sr_pseg_start = pseg_start;
nilfs->ns_pseg_offset = pseg_start + 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 = le64_to_cpu(sum->ss_create);
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;
}
try_next_pseg:
/* Standing on a course, or met an inconsistent state */
pseg_start += 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 */
brelse(bh_sum);
list_splice_tail(&segments, &ri->ri_used_segments);
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:
brelse(bh_sum);
nilfs_dispose_segment_list(&segments);
return ret < 0 ? ret : nilfs_warn_segment_error(nilfs->ns_sb, ret);
}