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Date: Mon, 15 Sep 2008 04:08:10 +0900
From: Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
Koji Sato <sato.koji@....ntt.co.jp>,
Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>
Subject: [PATCH 13/27] nilfs2: checkpoint file
From: Koji Sato <sato.koji@....ntt.co.jp>
This adds a meta data file which holds checkpoint entries in its data
blocks.
Signed-off-by: Koji Sato <sato.koji@....ntt.co.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>
---
fs/nilfs2/cpfile.c | 908 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nilfs2/cpfile.h | 45 +++
2 files changed, 953 insertions(+), 0 deletions(-)
create mode 100644 fs/nilfs2/cpfile.c
create mode 100644 fs/nilfs2/cpfile.h
diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
new file mode 100644
index 0000000..991633a
--- /dev/null
+++ b/fs/nilfs2/cpfile.c
@@ -0,0 +1,908 @@
+/*
+ * 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@...g.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, -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 cno,
+ 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);
+ 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;
+
+ out:
+ up_read(&NILFS_MDT(cpfile)->mi_sem);
+ return ret;
+}
+
+static ssize_t nilfs_cpfile_do_get_ssinfo(struct inode *cpfile, __u64 cno,
+ struct nilfs_cpinfo *ci, size_t nci)
+{
+ struct buffer_head *bh;
+ struct nilfs_cpfile_header *header;
+ struct nilfs_checkpoint *cp;
+ __u64 curr, next;
+ unsigned long curr_blkoff, next_blkoff;
+ void *kaddr;
+ int n, ret;
+
+ down_read(&NILFS_MDT(cpfile)->mi_sem);
+
+ if (cno == 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
+ curr = cno;
+ curr_blkoff = nilfs_cpfile_get_blkoff(cpfile, curr);
+ ret = nilfs_cpfile_get_checkpoint_block(cpfile, curr, 0, &bh);
+ if (ret < 0)
+ goto out;
+ kaddr = kmap_atomic(bh->b_page, KM_USER0);
+ for (n = 0; n < nci; n++) {
+ cp = nilfs_cpfile_block_get_checkpoint(
+ cpfile, curr, bh, kaddr);
+ nilfs_cpfile_checkpoint_to_cpinfo(cpfile, cp, &ci[n]);
+ next = le64_to_cpu(cp->cp_snapshot_list.ssl_next);
+ if (next == 0) {
+ curr = next;
+ n++;
+ break;
+ }
+ 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 (ret < 0)
+ goto out;
+ kaddr = kmap_atomic(bh->b_page, KM_USER0);
+ }
+ curr = next;
+ curr_blkoff = next_blkoff;
+ }
+ kunmap_atomic(kaddr, KM_USER0);
+ brelse(bh);
+ 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 cno, int mode,
+ struct nilfs_cpinfo *ci, size_t nci)
+{
+ switch (mode) {
+ case NILFS_CHECKPOINT:
+ return nilfs_cpfile_do_get_cpinfo(cpfile, cno, ci, nci);
+ case NILFS_SNAPSHOT:
+ return nilfs_cpfile_do_get_ssinfo(cpfile, cno, 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;
+ ssize_t nci;
+ int ret;
+
+ /* checkpoint number 0 is invalid */
+ if (cno == 0)
+ return -ENOENT;
+ nci = nilfs_cpfile_do_get_cpinfo(cpfile, cno, &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;
+}
diff --git a/fs/nilfs2/cpfile.h b/fs/nilfs2/cpfile.h
new file mode 100644
index 0000000..f097e90
--- /dev/null
+++ b/fs/nilfs2/cpfile.h
@@ -0,0 +1,45 @@
+/*
+ * cpfile.h - 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@...g.net>.
+ */
+
+#ifndef _NILFS_CPFILE_H
+#define _NILFS_CPFILE_H
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/nilfs2_fs.h>
+
+#define NILFS_CPFILE_GFP NILFS_MDT_GFP
+
+
+int nilfs_cpfile_get_checkpoint(struct inode *, __u64, int,
+ struct nilfs_checkpoint **,
+ struct buffer_head **);
+void nilfs_cpfile_put_checkpoint(struct inode *, __u64, struct buffer_head *);
+int nilfs_cpfile_delete_checkpoints(struct inode *, __u64, __u64);
+int nilfs_cpfile_delete_checkpoint(struct inode *, __u64);
+int nilfs_cpfile_change_cpmode(struct inode *, __u64, int);
+int nilfs_cpfile_is_snapshot(struct inode *, __u64);
+int nilfs_cpfile_get_stat(struct inode *, struct nilfs_cpstat *);
+ssize_t nilfs_cpfile_get_cpinfo(struct inode *, __u64, int,
+ struct nilfs_cpinfo *, size_t);
+
+#endif /* _NILFS_CPFILE_H */
--
1.5.6.3
--
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