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![Ryusuke Konishi](/assets/img/avatar_default.png)
Alberto Bertogli advised me about bio_alloc() use in nilfs: On Sat, 13 Jun 2009 22:52:40 -0300, Alberto Bertogli wrote: > By the way, those bio_alloc()s are using GFP_NOWAIT but it looks > like they could use at least GFP_NOIO or GFP_NOFS, since the caller > can (and sometimes do) sleep. The only caller is nilfs_submit_bh(), > which calls nilfs_submit_seg_bio() which can sleep calling > wait_for_completion(). This takes in the comment and replaces the use of GFP_NOWAIT flag with GFP_NOIO. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
438 lines
11 KiB
C
438 lines
11 KiB
C
/*
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* segbuf.c - NILFS segment buffer
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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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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*
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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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*
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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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*
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* Written by Ryusuke Konishi <ryusuke@osrg.net>
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*
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*/
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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 "page.h"
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#include "segbuf.h"
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static struct kmem_cache *nilfs_segbuf_cachep;
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static void nilfs_segbuf_init_once(void *obj)
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{
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memset(obj, 0, sizeof(struct nilfs_segment_buffer));
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}
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int __init nilfs_init_segbuf_cache(void)
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{
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nilfs_segbuf_cachep =
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kmem_cache_create("nilfs2_segbuf_cache",
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sizeof(struct nilfs_segment_buffer),
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0, SLAB_RECLAIM_ACCOUNT,
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nilfs_segbuf_init_once);
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return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0;
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}
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void nilfs_destroy_segbuf_cache(void)
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{
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kmem_cache_destroy(nilfs_segbuf_cachep);
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}
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struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
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{
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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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return NULL;
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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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return segbuf;
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}
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void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
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{
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kmem_cache_free(nilfs_segbuf_cachep, segbuf);
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}
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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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{
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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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}
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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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{
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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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}
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int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
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{
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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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if (unlikely(!bh))
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return -ENOMEM;
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nilfs_segbuf_add_segsum_buffer(segbuf, bh);
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return 0;
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}
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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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{
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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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if (unlikely(!bh))
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return -ENOMEM;
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nilfs_segbuf_add_payload_buffer(segbuf, bh);
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*bhp = bh;
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return 0;
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}
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int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
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time_t ctime)
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{
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int err;
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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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if (unlikely(err))
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return err;
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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_io_error = 0;
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return 0;
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}
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/*
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* Setup segument summary
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*/
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void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
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{
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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_pad = 0;
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}
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/*
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* CRC calculation routines
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*/
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void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf,
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u32 seed)
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{
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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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u32 crc;
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bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
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b_assoc_buffers);
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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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crc = crc32_le(seed,
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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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b_assoc_buffers) {
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bytes -= size;
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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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}
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raw_sum->ss_sumsum = cpu_to_le32(crc);
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}
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void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
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u32 seed)
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{
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struct buffer_head *bh;
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struct nilfs_segment_summary *raw_sum;
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void *kaddr;
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u32 crc;
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bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
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b_assoc_buffers);
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raw_sum = (struct nilfs_segment_summary *)bh->b_data;
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crc = crc32_le(seed,
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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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b_assoc_buffers) {
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crc = crc32_le(crc, bh->b_data, bh->b_size);
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}
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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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}
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raw_sum->ss_datasum = cpu_to_le32(crc);
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}
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void nilfs_release_buffers(struct list_head *list)
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{
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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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if (buffer_nilfs_allocated(bh)) {
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struct page *clone_page = bh->b_page;
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/* remove clone page */
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brelse(bh);
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page_cache_release(clone_page); /* for each bh */
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if (page_count(clone_page) <= 2) {
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lock_page(clone_page);
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nilfs_free_private_page(clone_page);
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}
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continue;
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}
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brelse(bh);
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}
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}
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/*
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* BIO operations
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*/
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static void nilfs_end_bio_write(struct bio *bio, int err)
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{
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const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
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struct nilfs_write_info *wi = 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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bio_put(bio);
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/* to be detected by submit_seg_bio() */
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}
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if (!uptodate)
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atomic_inc(&wi->err);
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bio_put(bio);
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complete(&wi->bio_event);
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}
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static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode)
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{
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struct bio *bio = wi->bio;
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int err;
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if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) {
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wait_for_completion(&wi->bio_event);
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wi->nbio--;
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if (unlikely(atomic_read(&wi->err))) {
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bio_put(bio);
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err = -EIO;
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goto failed;
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}
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}
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bio->bi_end_io = nilfs_end_bio_write;
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bio->bi_private = wi;
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bio_get(bio);
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submit_bio(mode, bio);
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if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
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bio_put(bio);
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err = -EOPNOTSUPP;
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goto failed;
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}
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wi->nbio++;
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bio_put(bio);
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wi->bio = NULL;
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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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wi->start = wi->end;
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return 0;
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failed:
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wi->bio = NULL;
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return err;
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}
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/**
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* nilfs_alloc_seg_bio - allocate a bio for writing segment.
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* @sb: super block
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* @start: beginning disk block number of this BIO.
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* @nr_vecs: request size of page vector.
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*
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* alloc_seg_bio() allocates a new BIO structure and initialize it.
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*
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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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*/
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static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start,
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int nr_vecs)
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{
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struct bio *bio;
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bio = bio_alloc(GFP_NOIO, nr_vecs);
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if (bio == NULL) {
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while (!bio && (nr_vecs >>= 1))
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bio = bio_alloc(GFP_NOIO, nr_vecs);
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}
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if (likely(bio)) {
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bio->bi_bdev = sb->s_bdev;
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bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9);
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}
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return bio;
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}
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void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
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struct nilfs_write_info *wi)
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{
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wi->bio = NULL;
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wi->rest_blocks = segbuf->sb_sum.nblocks;
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wi->max_pages = bio_get_nr_vecs(wi->sb->s_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->nbio = 0;
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wi->blocknr = segbuf->sb_pseg_start;
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atomic_set(&wi->err, 0);
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init_completion(&wi->bio_event);
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}
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static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh,
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int mode)
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{
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int len, err;
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BUG_ON(wi->nr_vecs <= 0);
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repeat:
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if (!wi->bio) {
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wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end,
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wi->nr_vecs);
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if (unlikely(!wi->bio))
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return -ENOMEM;
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}
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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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wi->end++;
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return 0;
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}
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/* bio is FULL */
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err = nilfs_submit_seg_bio(wi, mode);
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/* never submit current bh */
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if (likely(!err))
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goto repeat;
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return err;
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}
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int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
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struct nilfs_write_info *wi)
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{
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struct buffer_head *bh;
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int res, rw = WRITE;
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list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
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res = nilfs_submit_bh(wi, bh, rw);
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if (unlikely(res))
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goto failed_bio;
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}
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list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
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res = nilfs_submit_bh(wi, bh, rw);
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if (unlikely(res))
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goto failed_bio;
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}
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if (wi->bio) {
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/*
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* Last BIO is always sent through the following
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* submission.
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*/
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rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
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res = nilfs_submit_seg_bio(wi, rw);
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if (unlikely(res))
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goto failed_bio;
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}
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res = 0;
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out:
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return res;
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failed_bio:
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atomic_inc(&wi->err);
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goto out;
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}
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/**
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* nilfs_segbuf_wait - wait for completion of requested BIOs
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* @wi: nilfs_write_info
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*
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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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*
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* %-EIO - I/O error
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*/
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int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf,
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struct nilfs_write_info *wi)
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{
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int err = 0;
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if (!wi->nbio)
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return 0;
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do {
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wait_for_completion(&wi->bio_event);
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} while (--wi->nbio > 0);
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if (unlikely(atomic_read(&wi->err) > 0)) {
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printk(KERN_ERR "NILFS: IO error writing segment\n");
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err = -EIO;
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segbuf->sb_io_error = 1;
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}
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return err;
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}
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