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* segbuf.c - NILFS segment buffer
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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* Written by Ryusuke Konishi <ryusuke@osrg.net>
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#include <linux/buffer_head.h>
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#include <linux/writeback.h>
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#include <linux/crc32.h>
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#include <linux/backing-dev.h>
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#include <linux/slab.h>
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struct nilfs_write_info {
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struct the_nilfs *nilfs;
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int start, end; /* The region to be submitted */
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static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
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struct the_nilfs *nilfs);
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static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
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struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
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struct nilfs_segment_buffer *segbuf;
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segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
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if (unlikely(!segbuf))
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segbuf->sb_super = sb;
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INIT_LIST_HEAD(&segbuf->sb_list);
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INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
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INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
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segbuf->sb_super_root = NULL;
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init_completion(&segbuf->sb_bio_event);
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atomic_set(&segbuf->sb_err, 0);
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void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
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kmem_cache_free(nilfs_segbuf_cachep, segbuf);
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void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
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unsigned long offset, struct the_nilfs *nilfs)
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segbuf->sb_segnum = segnum;
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nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
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&segbuf->sb_fseg_end);
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segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
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segbuf->sb_rest_blocks =
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segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
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* nilfs_segbuf_map_cont - map a new log behind a given log
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* @segbuf: new segment buffer
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* @prev: segment buffer containing a log to be continued
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void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
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struct nilfs_segment_buffer *prev)
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segbuf->sb_segnum = prev->sb_segnum;
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segbuf->sb_fseg_start = prev->sb_fseg_start;
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segbuf->sb_fseg_end = prev->sb_fseg_end;
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segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
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segbuf->sb_rest_blocks =
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segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
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void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
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__u64 nextnum, struct the_nilfs *nilfs)
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segbuf->sb_nextnum = nextnum;
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segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
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int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
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struct buffer_head *bh;
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bh = sb_getblk(segbuf->sb_super,
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segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
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nilfs_segbuf_add_segsum_buffer(segbuf, bh);
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int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
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struct buffer_head **bhp)
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struct buffer_head *bh;
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bh = sb_getblk(segbuf->sb_super,
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segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
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nilfs_segbuf_add_payload_buffer(segbuf, bh);
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int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
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time_t ctime, __u64 cno)
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segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
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err = nilfs_segbuf_extend_segsum(segbuf);
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segbuf->sb_sum.flags = flags;
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segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
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segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
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segbuf->sb_sum.ctime = ctime;
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segbuf->sb_sum.cno = cno;
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* Setup segment summary
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void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
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struct nilfs_segment_summary *raw_sum;
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struct buffer_head *bh_sum;
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bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
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struct buffer_head, b_assoc_buffers);
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raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
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raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC);
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raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum));
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raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags);
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raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq);
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raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime);
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raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next);
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raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks);
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raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo);
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raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
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raw_sum->ss_cno = cpu_to_le64(segbuf->sb_sum.cno);
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* CRC calculation routines
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nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
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struct buffer_head *bh;
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struct nilfs_segment_summary *raw_sum;
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unsigned long size, bytes = segbuf->sb_sum.sumbytes;
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bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
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raw_sum = (struct nilfs_segment_summary *)bh->b_data;
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size = min_t(unsigned long, bytes, bh->b_size);
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(unsigned char *)raw_sum +
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sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
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size - (sizeof(raw_sum->ss_datasum) +
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sizeof(raw_sum->ss_sumsum)));
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list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
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size = min_t(unsigned long, bytes, bh->b_size);
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crc = crc32_le(crc, bh->b_data, size);
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raw_sum->ss_sumsum = cpu_to_le32(crc);
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static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
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struct buffer_head *bh;
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struct nilfs_segment_summary *raw_sum;
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bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
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raw_sum = (struct nilfs_segment_summary *)bh->b_data;
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(unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
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bh->b_size - sizeof(raw_sum->ss_datasum));
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list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
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crc = crc32_le(crc, bh->b_data, bh->b_size);
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list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
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kaddr = kmap_atomic(bh->b_page, KM_USER0);
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crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
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kunmap_atomic(kaddr, KM_USER0);
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raw_sum->ss_datasum = cpu_to_le32(crc);
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nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
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struct nilfs_super_root *raw_sr;
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struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
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raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
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srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
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(unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
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srsize - sizeof(raw_sr->sr_sum));
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raw_sr->sr_sum = cpu_to_le32(crc);
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static void nilfs_release_buffers(struct list_head *list)
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struct buffer_head *bh, *n;
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list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
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list_del_init(&bh->b_assoc_buffers);
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static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
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nilfs_release_buffers(&segbuf->sb_segsum_buffers);
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nilfs_release_buffers(&segbuf->sb_payload_buffers);
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segbuf->sb_super_root = NULL;
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* Iterators for segment buffers
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void nilfs_clear_logs(struct list_head *logs)
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struct nilfs_segment_buffer *segbuf;
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list_for_each_entry(segbuf, logs, sb_list)
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nilfs_segbuf_clear(segbuf);
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void nilfs_truncate_logs(struct list_head *logs,
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struct nilfs_segment_buffer *last)
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struct nilfs_segment_buffer *n, *segbuf;
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segbuf = list_prepare_entry(last, logs, sb_list);
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list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
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list_del_init(&segbuf->sb_list);
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nilfs_segbuf_clear(segbuf);
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nilfs_segbuf_free(segbuf);
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int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
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struct nilfs_segment_buffer *segbuf;
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list_for_each_entry(segbuf, logs, sb_list) {
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ret = nilfs_segbuf_write(segbuf, nilfs);
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int nilfs_wait_on_logs(struct list_head *logs)
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struct nilfs_segment_buffer *segbuf;
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list_for_each_entry(segbuf, logs, sb_list) {
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err = nilfs_segbuf_wait(segbuf);
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* nilfs_add_checksums_on_logs - add checksums on the logs
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* @logs: list of segment buffers storing target logs
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* @seed: checksum seed value
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void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
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struct nilfs_segment_buffer *segbuf;
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list_for_each_entry(segbuf, logs, sb_list) {
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if (segbuf->sb_super_root)
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nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
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nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
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nilfs_segbuf_fill_in_data_crc(segbuf, seed);
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static void nilfs_end_bio_write(struct bio *bio, int err)
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const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
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struct nilfs_segment_buffer *segbuf = bio->bi_private;
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if (err == -EOPNOTSUPP) {
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set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
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/* to be detected by submit_seg_bio() */
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atomic_inc(&segbuf->sb_err);
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complete(&segbuf->sb_bio_event);
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static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
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struct nilfs_write_info *wi, int mode)
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struct bio *bio = wi->bio;
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if (segbuf->sb_nbio > 0 &&
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bdi_write_congested(segbuf->sb_super->s_bdi)) {
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wait_for_completion(&segbuf->sb_bio_event);
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if (unlikely(atomic_read(&segbuf->sb_err))) {
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bio->bi_end_io = nilfs_end_bio_write;
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bio->bi_private = segbuf;
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submit_bio(mode, bio);
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if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
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wi->rest_blocks -= wi->end - wi->start;
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wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
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* nilfs_alloc_seg_bio - allocate a new bio for writing log
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* @nilfs: nilfs object
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* @start: start block number of the bio
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* @nr_vecs: request size of page vector.
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* Return Value: On success, pointer to the struct bio is returned.
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* On error, NULL is returned.
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static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
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bio = bio_alloc(GFP_NOIO, nr_vecs);
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while (!bio && (nr_vecs >>= 1))
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bio = bio_alloc(GFP_NOIO, nr_vecs);
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bio->bi_bdev = nilfs->ns_bdev;
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bio->bi_sector = start << (nilfs->ns_blocksize_bits - 9);
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static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
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struct nilfs_write_info *wi)
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wi->rest_blocks = segbuf->sb_sum.nblocks;
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wi->max_pages = bio_get_nr_vecs(wi->nilfs->ns_bdev);
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wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
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wi->start = wi->end = 0;
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wi->blocknr = segbuf->sb_pseg_start;
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static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
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struct nilfs_write_info *wi,
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struct buffer_head *bh, int mode)
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BUG_ON(wi->nr_vecs <= 0);
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wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
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if (unlikely(!wi->bio))
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len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
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if (len == bh->b_size) {
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err = nilfs_segbuf_submit_bio(segbuf, wi, mode);
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/* never submit current bh */
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* nilfs_segbuf_write - submit write requests of a log
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* @segbuf: buffer storing a log to be written
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* @nilfs: nilfs object
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* Return Value: On Success, 0 is returned. On Error, one of the following
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* negative error code is returned.
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* %-ENOMEM - Insufficient memory available.
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static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
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struct the_nilfs *nilfs)
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struct nilfs_write_info wi;
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struct buffer_head *bh;
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int res = 0, rw = WRITE;
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nilfs_segbuf_prepare_write(segbuf, &wi);
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list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
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res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
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list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
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res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
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* Last BIO is always sent through the following
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res = nilfs_segbuf_submit_bio(segbuf, &wi, rw);
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* nilfs_segbuf_wait - wait for completion of requested BIOs
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* @segbuf: segment buffer
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* Return Value: On Success, 0 is returned. On Error, one of the following
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* negative error code is returned.
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static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
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if (!segbuf->sb_nbio)
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wait_for_completion(&segbuf->sb_bio_event);
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} while (--segbuf->sb_nbio > 0);
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if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
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printk(KERN_ERR "NILFS: IO error writing segment\n");