/*
* cpfile.c - NILFS checkpoint file.
*
* Copyright (C) 2006-2008 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 Koji Sato <koji@osrg.net>.
*/
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/errno.h>
#include <linux/nilfs2_fs.h>
#include "mdt.h"
#include "cpfile.h"
static inline unsigned long
nilfs_cpfile_checkpoints_per_block(const struct inode *cpfile)
{
return NILFS_MDT(cpfile)->mi_entries_per_block;
}
/* block number from the beginning of the file */
static unsigned long
nilfs_cpfile_get_blkoff(const struct inode *cpfile, __u64 cno)
{
__u64 tcno;
BUG_ON(cno == 0); /* checkpoint number 0 is invalid */
tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
return (unsigned long)tcno;
}
/* offset in block */
static unsigned long
nilfs_cpfile_get_offset(const struct inode *cpfile, __u64 cno)
{
__u64 tcno = cno + NILFS_MDT(cpfile)->mi_first_entry_offset - 1;
return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
}
static unsigned long
nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
__u64 curr,
__u64 max)
{
return min_t(__u64,
nilfs_cpfile_checkpoints_per_block(cpfile) -
nilfs_cpfile_get_offset(cpfile, curr),
max - curr);
}
static inline int nilfs_cpfile_is_in_first(const struct inode *cpfile,
__u64 cno)
{
return nilfs_cpfile_get_blkoff(cpfile, cno) == 0;
}
static unsigned int
nilfs_cpfile_block_add_valid_checkpoints(const struct inode *cpfile,
struct buffer_head *bh,
void *kaddr,
unsigned int n)
{
struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
unsigned int count;
count = le32_to_cpu(cp->cp_checkpoints_count) + n;
cp->cp_checkpoints_count = cpu_to_le32(count);
return count;
}
static unsigned int
nilfs_cpfile_block_sub_valid_checkpoints(const struct inode *cpfile,
struct buffer_head *bh,
void *kaddr,
unsigned int n)
{
struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
unsigned int count;
BUG_ON(le32_to_cpu(cp->cp_checkpoints_count) < n);
count = le32_to_cpu(cp->cp_checkpoints_count) - n;
cp->cp_checkpoints_count = cpu_to_le32(count);
return count;
}
static inline struct nilfs_cpfile_header *
nilfs_cpfile_block_get_header(const struct inode *cpfile,
struct buffer_head *bh,
void *kaddr)
{
return kaddr + bh_offset(bh);
}
static struct nilfs_checkpoint *
nilfs_cpfile_block_get_checkpoint(const struct inode *cpfile, __u64 cno,
struct buffer_head *bh,
void *kaddr)
{
return kaddr + bh_offset(bh) + nilfs_cpfile_get_offset(cpfile, cno) *
NILFS_MDT(cpfile)->mi_entry_size;
}
static void nilfs_cpfile_block_init(struct inode *cpfile,
struct buffer_head *bh,
void *kaddr)
{
struct nilfs_checkpoint *cp = kaddr + bh_offset(bh);
size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
int n = nilfs_cpfile_checkpoints_per_block(cpfile);
while (n-- > 0) {
nilfs_checkpoint_set_invalid(cp);
cp = (void *)cp + cpsz;
}
}
static inline int nilfs_cpfile_get_header_block(struct inode *cpfile,
struct buffer_head **bhp)
{
return nilfs_mdt_get_block(cpfile, 0, 0, NULL, bhp);
}
static inline int nilfs_cpfile_get_checkpoint_block(struct inode *cpfile,
__u64 cno,
int create,
struct buffer_head **bhp)
{
return nilfs_mdt_get_block(cpfile,
nilfs_cpfile_get_blkoff(cpfile, cno),
create, nilfs_cpfile_block_init, bhp);
}
static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
__u64 cno)
{
return nilfs_mdt_delete_block(cpfile,
nilfs_cpfile_get_blkoff(cpfile, cno));
}
/**
* nilfs_cpfile_get_checkpoint - get a checkpoint
* @cpfile: inode of checkpoint file
* @cno: checkpoint number
* @create: create flag
* @cpp: pointer to a checkpoint
* @bhp: pointer to a buffer head
*
* Description: nilfs_cpfile_get_checkpoint() acquires the checkpoint
* specified by @cno. A new checkpoint will be created if @cno is the current
* checkpoint number and @create is nonzero.
*
* Return Value: On success, 0 is returned, and the checkpoint and the
* buffer head of the buffer on which the checkpoint is located are stored in
* the place pointed by @cpp and @bhp, respectively. On error, one of the
* following negative error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*
* %-ENOENT - No such checkpoint.
*/
int nilfs_cpfile_get_checkpoint(struct inode *cpfile,
__u64 cno,
int create,
struct nilfs_checkpoint **cpp,
struct buffer_head **bhp)
{
struct buffer_head *header_bh, *cp_bh;
struct nilfs_cpfile_header *header;
struct nilfs_checkpoint *cp;
void *kaddr;
int ret;
BUG_ON(cno < 1 || cno > nilfs_mdt_cno(cpfile) ||
(cno < nilfs_mdt_cno(cpfile) && create));
down_write(&NILFS_MDT(cpfile)->mi_sem);
ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
if (ret < 0)
goto out_sem;
ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, create, &cp_bh);
if (ret < 0)
goto out_header;
kaddr = kmap(cp_bh->b_page);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
if (nilfs_checkpoint_invalid(cp)) {
if (!create) {
kunmap(cp_bh->b_page);
brelse(cp_bh);
ret = -ENOENT;
goto out_header;
}
/* a newly-created checkpoint */
nilfs_checkpoint_clear_invalid(cp);
if (!nilfs_cpfile_is_in_first(cpfile, cno))
nilfs_cpfile_block_add_valid_checkpoints(cpfile, cp_bh,
kaddr, 1);
nilfs_mdt_mark_buffer_dirty(cp_bh);
kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
header = nilfs_cpfile_block_get_header(cpfile, header_bh,
kaddr);
le64_add_cpu(&header->ch_ncheckpoints, 1);
kunmap_atomic(kaddr, KM_USER0);
nilfs_mdt_mark_buffer_dirty(header_bh);
nilfs_mdt_mark_dirty(cpfile);
}
if (cpp != NULL)
*cpp = cp;
*bhp = cp_bh;
out_header:
brelse(header_bh);
out_sem:
up_write(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
/**
* nilfs_cpfile_put_checkpoint - put a checkpoint
* @cpfile: inode of checkpoint file
* @cno: checkpoint number
* @bh: buffer head
*
* Description: nilfs_cpfile_put_checkpoint() releases the checkpoint
* specified by @cno. @bh must be the buffer head which has been returned by
* a previous call to nilfs_cpfile_get_checkpoint() with @cno.
*/
void nilfs_cpfile_put_checkpoint(struct inode *cpfile, __u64 cno,
struct buffer_head *bh)
{
kunmap(bh->b_page);
brelse(bh);
}
/**
* nilfs_cpfile_delete_checkpoints - delete checkpoints
* @cpfile: inode of checkpoint file
* @start: start checkpoint number
* @end: end checkpoint numer
*
* Description: nilfs_cpfile_delete_checkpoints() deletes the checkpoints in
* the period from @start to @end, excluding @end itself. The checkpoints
* which have been already deleted are ignored.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*
* %-EINVAL - invalid checkpoints.
*/
int nilfs_cpfile_delete_checkpoints(struct inode *cpfile,
__u64 start,
__u64 end)
{
struct buffer_head *header_bh, *cp_bh;
struct nilfs_cpfile_header *header;
struct nilfs_checkpoint *cp;
size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
__u64 cno;
void *kaddr;
unsigned long tnicps;
int ret, ncps, nicps, count, i;
if ((start == 0) || (start > end)) {
printk(KERN_CRIT "%s: start = %llu, end = %llu\n",
__func__,
(unsigned long long)start,
(unsigned long long)end);
BUG();
}
/* cannot delete the latest checkpoint */
if (start == nilfs_mdt_cno(cpfile) - 1)
return -EPERM;
down_write(&NILFS_MDT(cpfile)->mi_sem);
ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
if (ret < 0)
goto out_sem;
tnicps = 0;
for (cno = start; cno < end; cno += ncps) {
ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, end);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
if (ret < 0) {
if (ret != -ENOENT)
goto out_sem;
/* skip hole */
ret = 0;
continue;
}
kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
cp = nilfs_cpfile_block_get_checkpoint(
cpfile, cno, cp_bh, kaddr);
nicps = 0;
for (i = 0; i < ncps; i++, cp = (void *)cp + cpsz) {
BUG_ON(nilfs_checkpoint_snapshot(cp));
if (!nilfs_checkpoint_invalid(cp)) {
nilfs_checkpoint_set_invalid(cp);
nicps++;
}
}
if (nicps > 0) {
tnicps += nicps;
nilfs_mdt_mark_buffer_dirty(cp_bh);
nilfs_mdt_mark_dirty(cpfile);
if (!nilfs_cpfile_is_in_first(cpfile, cno) &&
(count = nilfs_cpfile_block_sub_valid_checkpoints(
cpfile, cp_bh, kaddr, nicps)) == 0) {
/* make hole */
kunmap_atomic(kaddr, KM_USER0);
brelse(cp_bh);
ret = nilfs_cpfile_delete_checkpoint_block(
cpfile, cno);
if (ret == 0)
continue;
printk(KERN_ERR "%s: cannot delete block\n",
__func__);
goto out_sem;
}
}
kunmap_atomic(kaddr, KM_USER0);
brelse(cp_bh);
}
if (tnicps > 0) {
kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
header = nilfs_cpfile_block_get_header(cpfile, header_bh,
kaddr);
le64_add_cpu(&header->ch_ncheckpoints, -(u64)tnicps);
nilfs_mdt_mark_buffer_dirty(header_bh);
nilfs_mdt_mark_dirty(cpfile);
kunmap_atomic(kaddr, KM_USER0);
}
brelse(header_bh);
out_sem:
up_write(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
static void nilfs_cpfile_checkpoint_to_cpinfo(struct inode *cpfile,
struct nilfs_checkpoint *cp,
struct nilfs_cpinfo *ci)
{
ci->ci_flags = le32_to_cpu(cp->cp_flags);
ci->ci_cno = le64_to_cpu(cp->cp_cno);
ci->ci_create = le64_to_cpu(cp->cp_create);
ci->ci_nblk_inc = le64_to_cpu(cp->cp_nblk_inc);
ci->ci_inodes_count = le64_to_cpu(cp->cp_inodes_count);
ci->ci_blocks_count = le64_to_cpu(cp->cp_blocks_count);
ci->ci_next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
}
static ssize_t nilfs_cpfile_do_get_cpinfo(struct inode *cpfile, __u64 *cnop,
struct nilfs_cpinfo *ci, size_t nci)
{
struct nilfs_checkpoint *cp;
struct buffer_head *bh;
size_t cpsz = NILFS_MDT(cpfile)->mi_entry_size;
__u64 cur_cno = nilfs_mdt_cno(cpfile), cno = *cnop;
void *kaddr;
int n, ret;
int ncps, i;
down_read(&NILFS_MDT(cpfile)->mi_sem);
for (n = 0; cno < cur_cno && n < nci; cno += ncps) {
ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
if (ret < 0) {
if (ret != -ENOENT)
goto out;
continue; /* skip hole */
}
kaddr = kmap_atomic(bh->b_page, KM_USER0);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
for (i = 0; i < ncps && n < nci; i++, cp = (void *)cp + cpsz) {
if (!nilfs_checkpoint_invalid(cp))
nilfs_cpfile_checkpoint_to_cpinfo(
cpfile, cp, &ci[n++]);
}
kunmap_atomic(kaddr, KM_USER0);
brelse(bh);
}
ret = n;
if (n > 0)
*cnop = ci[n - 1].ci_cno + 1;
out:
up_read(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 *cnop,
struct nilfs_cpinfo *ci, size_t nci)
{
struct buffer_head *bh;
struct nilfs_cpfile_header *header;
struct nilfs_checkpoint *cp;
__u64 curr = *cnop, next;
unsigned long curr_blkoff, next_blkoff;
void *kaddr;
int n = 0, ret;
down_read(&NILFS_MDT(cpfile)->mi_sem);
if (curr == 0) {
ret = nilfs_cpfile_get_header_block(cpfile, &bh);
if (ret < 0)
goto out;
kaddr = kmap_atomic(bh->b_page, KM_USER0);
header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
curr = le64_to_cpu(header->ch_snapshot_list.ssl_next);
kunmap_atomic(kaddr, KM_USER0);
brelse(bh);
if (curr == 0) {
ret = 0;
goto out;
}
} else if (unlikely(curr == ~(__u64)0)) {
ret = 0;
goto out;
}
curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
if (unlikely(ret < 0)) {
if (ret == -ENOENT)
ret = 0; /* No snapshots (started from a hole block) */
goto out;
}
kaddr = kmap_atomic(bh->b_page, KM_USER0);
while (n < nci) {
cp = nilfs_cpfile_block_get_checkpoint(cpfile, curr, bh, kaddr);
curr = ~(__u64)0; /* Terminator */
if (unlikely(nilfs_checkpoint_invalid(cp) ||
!nilfs_checkpoint_snapshot(cp)))
break;
nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n++]);
next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
if (next == 0)
break; /* reach end of the snapshot list */
next_blkoff = nilfs_cpfile_get_blkoff(cpfile, next);
if (curr_blkoff != next_blkoff) {
kunmap_atomic(kaddr, KM_USER0);
brelse(bh);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, next,
0, &bh);
if (unlikely(ret < 0)) {
WARN_ON(ret == -ENOENT);
goto out;
}
kaddr = kmap_atomic(bh->b_page, KM_USER0);
}
curr = next;
curr_blkoff = next_blkoff;
}
kunmap_atomic(kaddr, KM_USER0);
brelse(bh);
*cnop = curr;
ret = n;
out:
up_read(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
/**
* nilfs_cpfile_get_cpinfo -
* @cpfile:
* @cno:
* @ci:
* @nci:
*/
ssize_t nilfs_cpfile_get_cpinfo(struct inode *cpfile, __u64 *cnop, int mode,
struct nilfs_cpinfo *ci, size_t nci)
{
switch (mode) {
case NILFS_CHECKPOINT:
return nilfs_cpfile_do_get_cpinfo(cpfile, cnop, ci, nci);
case NILFS_SNAPSHOT:
return nilfs_cpfile_do_get_ssinfo(cpfile, cnop, ci, nci);
default:
return -EINVAL;
}
}
/**
* nilfs_cpfile_delete_checkpoint -
* @cpfile:
* @cno:
*/
int nilfs_cpfile_delete_checkpoint(struct inode *cpfile, __u64 cno)
{
struct nilfs_cpinfo ci;
__u64 tcno = cno;
ssize_t nci;
int ret;
/* checkpoint number 0 is invalid */
if (cno == 0)
return -ENOENT;
nci = nilfs_cpfile_do_get_cpinfo(cpfile, &tcno, &ci, 1);
if (nci < 0)
return nci;
else if (nci == 0 || ci.ci_cno != cno)
return -ENOENT;
/* cannot delete the latest checkpoint nor snapshots */
ret = nilfs_cpinfo_snapshot(&ci);
if (ret < 0)
return ret;
else if (ret > 0 || cno == nilfs_mdt_cno(cpfile) - 1)
return -EPERM;
return nilfs_cpfile_delete_checkpoints(cpfile, cno, cno + 1);
}
static struct nilfs_snapshot_list *
nilfs_cpfile_block_get_snapshot_list(const struct inode *cpfile,
__u64 cno,
struct buffer_head *bh,
void *kaddr)
{
struct nilfs_cpfile_header *header;
struct nilfs_checkpoint *cp;
struct nilfs_snapshot_list *list;
if (cno != 0) {
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
list = &cp->cp_snapshot_list;
} else {
header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
list = &header->ch_snapshot_list;
}
return list;
}
static int nilfs_cpfile_set_snapshot(struct inode *cpfile, __u64 cno)
{
struct buffer_head *header_bh, *curr_bh, *prev_bh, *cp_bh;
struct nilfs_cpfile_header *header;
struct nilfs_checkpoint *cp;
struct nilfs_snapshot_list *list;
__u64 curr, prev;
unsigned long curr_blkoff, prev_blkoff;
void *kaddr;
int ret;
down_write(&NILFS_MDT(cpfile)->mi_sem);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
if (ret < 0)
goto out_sem;
kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
if (nilfs_checkpoint_invalid(cp)) {
ret = -ENOENT;
kunmap_atomic(kaddr, KM_USER0);
goto out_cp;
}
if (nilfs_checkpoint_snapshot(cp)) {
ret = 0;
kunmap_atomic(kaddr, KM_USER0);
goto out_cp;
}
kunmap_atomic(kaddr, KM_USER0);
ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
if (ret < 0)
goto out_cp;
kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
list = &header->ch_snapshot_list;
curr_bh = header_bh;
get_bh(curr_bh);
curr = 0;
curr_blkoff = 0;
prev = le64_to_cpu(list->ssl_prev);
while (prev > cno) {
prev_blkoff = nilfs_cpfile_get_blkoff(cpfile, prev);
curr = prev;
if (curr_blkoff != prev_blkoff) {
kunmap_atomic(kaddr, KM_USER0);
brelse(curr_bh);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr,
0, &curr_bh);
if (ret < 0)
goto out_header;
kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
}
curr_blkoff = prev_blkoff;
cp = nilfs_cpfile_block_get_checkpoint(
cpfile, curr, curr_bh, kaddr);
list = &cp->cp_snapshot_list;
prev = le64_to_cpu(list->ssl_prev);
}
kunmap_atomic(kaddr, KM_USER0);
if (prev != 0) {
ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
&prev_bh);
if (ret < 0)
goto out_curr;
} else {
prev_bh = header_bh;
get_bh(prev_bh);
}
kaddr = kmap_atomic(curr_bh->b_page, KM_USER0);
list = nilfs_cpfile_block_get_snapshot_list(
cpfile, curr, curr_bh, kaddr);
list->ssl_prev = cpu_to_le64(cno);
kunmap_atomic(kaddr, KM_USER0);
kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
cp->cp_snapshot_list.ssl_next = cpu_to_le64(curr);
cp->cp_snapshot_list.ssl_prev = cpu_to_le64(prev);
nilfs_checkpoint_set_snapshot(cp);
kunmap_atomic(kaddr, KM_USER0);
kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
list = nilfs_cpfile_block_get_snapshot_list(
cpfile, prev, prev_bh, kaddr);
list->ssl_next = cpu_to_le64(cno);
kunmap_atomic(kaddr, KM_USER0);
kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
le64_add_cpu(&header->ch_nsnapshots, 1);
kunmap_atomic(kaddr, KM_USER0);
nilfs_mdt_mark_buffer_dirty(prev_bh);
nilfs_mdt_mark_buffer_dirty(curr_bh);
nilfs_mdt_mark_buffer_dirty(cp_bh);
nilfs_mdt_mark_buffer_dirty(header_bh);
nilfs_mdt_mark_dirty(cpfile);
brelse(prev_bh);
out_curr:
brelse(curr_bh);
out_header:
brelse(header_bh);
out_cp:
brelse(cp_bh);
out_sem:
up_write(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
static int nilfs_cpfile_clear_snapshot(struct inode *cpfile, __u64 cno)
{
struct buffer_head *header_bh, *next_bh, *prev_bh, *cp_bh;
struct nilfs_cpfile_header *header;
struct nilfs_checkpoint *cp;
struct nilfs_snapshot_list *list;
__u64 next, prev;
void *kaddr;
int ret;
down_write(&NILFS_MDT(cpfile)->mi_sem);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &cp_bh);
if (ret < 0)
goto out_sem;
kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
if (nilfs_checkpoint_invalid(cp)) {
ret = -ENOENT;
kunmap_atomic(kaddr, KM_USER0);
goto out_cp;
}
if (!nilfs_checkpoint_snapshot(cp)) {
ret = 0;
kunmap_atomic(kaddr, KM_USER0);
goto out_cp;
}
list = &cp->cp_snapshot_list;
next = le64_to_cpu(list->ssl_next);
prev = le64_to_cpu(list->ssl_prev);
kunmap_atomic(kaddr, KM_USER0);
ret = nilfs_cpfile_get_header_block(cpfile, &header_bh);
if (ret < 0)
goto out_cp;
if (next != 0) {
ret = nilfs_cpfile_get_checkpoint_block(cpfile, next, 0,
&next_bh);
if (ret < 0)
goto out_header;
} else {
next_bh = header_bh;
get_bh(next_bh);
}
if (prev != 0) {
ret = nilfs_cpfile_get_checkpoint_block(cpfile, prev, 0,
&prev_bh);
if (ret < 0)
goto out_next;
} else {
prev_bh = header_bh;
get_bh(prev_bh);
}
kaddr = kmap_atomic(next_bh->b_page, KM_USER0);
list = nilfs_cpfile_block_get_snapshot_list(
cpfile, next, next_bh, kaddr);
list->ssl_prev = cpu_to_le64(prev);
kunmap_atomic(kaddr, KM_USER0);
kaddr = kmap_atomic(prev_bh->b_page, KM_USER0);
list = nilfs_cpfile_block_get_snapshot_list(
cpfile, prev, prev_bh, kaddr);
list->ssl_next = cpu_to_le64(next);
kunmap_atomic(kaddr, KM_USER0);
kaddr = kmap_atomic(cp_bh->b_page, KM_USER0);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, cp_bh, kaddr);
cp->cp_snapshot_list.ssl_next = cpu_to_le64(0);
cp->cp_snapshot_list.ssl_prev = cpu_to_le64(0);
nilfs_checkpoint_clear_snapshot(cp);
kunmap_atomic(kaddr, KM_USER0);
kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
header = nilfs_cpfile_block_get_header(cpfile, header_bh, kaddr);
le64_add_cpu(&header->ch_nsnapshots, -1);
kunmap_atomic(kaddr, KM_USER0);
nilfs_mdt_mark_buffer_dirty(next_bh);
nilfs_mdt_mark_buffer_dirty(prev_bh);
nilfs_mdt_mark_buffer_dirty(cp_bh);
nilfs_mdt_mark_buffer_dirty(header_bh);
nilfs_mdt_mark_dirty(cpfile);
brelse(prev_bh);
out_next:
brelse(next_bh);
out_header:
brelse(header_bh);
out_cp:
brelse(cp_bh);
out_sem:
up_write(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
/**
* nilfs_cpfile_is_snapshot -
* @cpfile: inode of checkpoint file
* @cno: checkpoint number
*
* Description:
*
* Return Value: On success, 1 is returned if the checkpoint specified by
* @cno is a snapshot, or 0 if not. On error, one of the following negative
* error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*
* %-ENOENT - No such checkpoint.
*/
int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
{
struct buffer_head *bh;
struct nilfs_checkpoint *cp;
void *kaddr;
int ret;
down_read(&NILFS_MDT(cpfile)->mi_sem);
ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
if (ret < 0)
goto out;
kaddr = kmap_atomic(bh->b_page, KM_USER0);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
ret = nilfs_checkpoint_snapshot(cp);
kunmap_atomic(kaddr, KM_USER0);
brelse(bh);
out:
up_read(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
/**
* nilfs_cpfile_change_cpmode - change checkpoint mode
* @cpfile: inode of checkpoint file
* @cno: checkpoint number
* @status: mode of checkpoint
*
* Description: nilfs_change_cpmode() changes the mode of the checkpoint
* specified by @cno. The mode @mode is NILFS_CHECKPOINT or NILFS_SNAPSHOT.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*
* %-ENOENT - No such checkpoint.
*/
int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
{
struct the_nilfs *nilfs;
int ret;
nilfs = NILFS_MDT(cpfile)->mi_nilfs;
switch (mode) {
case NILFS_CHECKPOINT:
/*
* Check for protecting existing snapshot mounts:
* bd_mount_sem is used to make this operation atomic and
* exclusive with a new mount job. Though it doesn't cover
* umount, it's enough for the purpose.
*/
down(&nilfs->ns_bdev->bd_mount_sem);
if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {
/* Current implementation does not have to protect
plain read-only mounts since they are exclusive
with a read/write mount and are protected from the
cleaner. */
ret = -EBUSY;
} else
ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
up(&nilfs->ns_bdev->bd_mount_sem);
return ret;
case NILFS_SNAPSHOT:
return nilfs_cpfile_set_snapshot(cpfile, cno);
default:
return -EINVAL;
}
}
/**
* nilfs_cpfile_get_stat - get checkpoint statistics
* @cpfile: inode of checkpoint file
* @stat: pointer to a structure of checkpoint statistics
*
* Description: nilfs_cpfile_get_stat() returns information about checkpoints.
*
* Return Value: On success, 0 is returned, and checkpoints information is
* stored in the place pointed by @stat. On error, one of the following
* negative error codes is returned.
*
* %-EIO - I/O error.
*
* %-ENOMEM - Insufficient amount of memory available.
*/
int nilfs_cpfile_get_stat(struct inode *cpfile, struct nilfs_cpstat *cpstat)
{
struct buffer_head *bh;
struct nilfs_cpfile_header *header;
void *kaddr;
int ret;
down_read(&NILFS_MDT(cpfile)->mi_sem);
ret = nilfs_cpfile_get_header_block(cpfile, &bh);
if (ret < 0)
goto out_sem;
kaddr = kmap_atomic(bh->b_page, KM_USER0);
header = nilfs_cpfile_block_get_header(cpfile, bh, kaddr);
cpstat->cs_cno = nilfs_mdt_cno(cpfile);
cpstat->cs_ncps = le64_to_cpu(header->ch_ncheckpoints);
cpstat->cs_nsss = le64_to_cpu(header->ch_nsnapshots);
kunmap_atomic(kaddr, KM_USER0);
brelse(bh);
out_sem:
up_read(&NILFS_MDT(cpfile)->mi_sem);
return ret;
}
