/* * segbuf.c - NILFS segment buffer * * Copyright (C) 2005-2008 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 Ryusuke Konishi <ryusuke@osrg.net> * */ #include <linux/buffer_head.h> #include <linux/writeback.h> #include <linux/crc32.h> #include "page.h" #include "segbuf.h" #include "seglist.h" static struct kmem_cache *nilfs_segbuf_cachep; static void nilfs_segbuf_init_once(void *obj) { memset(obj, 0, sizeof(struct nilfs_segment_buffer)); } int __init nilfs_init_segbuf_cache(void) { nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache", sizeof(struct nilfs_segment_buffer), 0, SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once); return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0; } void nilfs_destroy_segbuf_cache(void) { kmem_cache_destroy(nilfs_segbuf_cachep); } struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb) { struct nilfs_segment_buffer *segbuf; segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS); if (unlikely(!segbuf)) return NULL; segbuf->sb_super = sb; INIT_LIST_HEAD(&segbuf->sb_list); INIT_LIST_HEAD(&segbuf->sb_segsum_buffers); INIT_LIST_HEAD(&segbuf->sb_payload_buffers); return segbuf; } void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf) { kmem_cache_free(nilfs_segbuf_cachep, segbuf); } void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum, unsigned long offset, struct the_nilfs *nilfs) { segbuf->sb_segnum = segnum; nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start, &segbuf->sb_fseg_end); segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset; segbuf->sb_rest_blocks = segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1; } void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf, __u64 nextnum, struct the_nilfs *nilfs) { segbuf->sb_nextnum = nextnum; segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum); } int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf) { struct buffer_head *bh; bh = sb_getblk(segbuf->sb_super, segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk); if (unlikely(!bh)) return -ENOMEM; nilfs_segbuf_add_segsum_buffer(segbuf, bh); return 0; } int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf, struct buffer_head **bhp) { struct buffer_head *bh; bh = sb_getblk(segbuf->sb_super, segbuf->sb_pseg_start + segbuf->sb_sum.nblocks); if (unlikely(!bh)) return -ENOMEM; nilfs_segbuf_add_payload_buffer(segbuf, bh); *bhp = bh; return 0; } int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags, time_t ctime) { int err; segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0; err = nilfs_segbuf_extend_segsum(segbuf); if (unlikely(err)) return err; segbuf->sb_sum.flags = flags; segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary); segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0; segbuf->sb_sum.ctime = ctime; segbuf->sb_io_error = 0; return 0; } /* * Setup segument summary */ void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf) { struct nilfs_segment_summary *raw_sum; struct buffer_head *bh_sum; bh_sum = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head, b_assoc_buffers); raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data; raw_sum->ss_magic = cpu_to_le32(NILFS_SEGSUM_MAGIC); raw_sum->ss_bytes = cpu_to_le16(sizeof(*raw_sum)); raw_sum->ss_flags = cpu_to_le16(segbuf->sb_sum.flags); raw_sum->ss_seq = cpu_to_le64(segbuf->sb_sum.seg_seq); raw_sum->ss_create = cpu_to_le64(segbuf->sb_sum.ctime); raw_sum->ss_next = cpu_to_le64(segbuf->sb_sum.next); raw_sum->ss_nblocks = cpu_to_le32(segbuf->sb_sum.nblocks); raw_sum->ss_nfinfo = cpu_to_le32(segbuf->sb_sum.nfinfo); raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes); raw_sum->ss_pad = 0; } /* * CRC calculation routines */ void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed) { struct buffer_head *bh; struct nilfs_segment_summary *raw_sum; unsigned long size, bytes = segbuf->sb_sum.sumbytes; u32 crc; bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head, b_assoc_buffers); raw_sum = (struct nilfs_segment_summary *)bh->b_data; size = min_t(unsigned long, bytes, bh->b_size); crc = crc32_le(seed, (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum), size - (sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum))); list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) { bytes -= size; size = min_t(unsigned long, bytes, bh->b_size); crc = crc32_le(crc, bh->b_data, size); } raw_sum->ss_sumsum = cpu_to_le32(crc); } void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf, u32 seed) { struct buffer_head *bh; struct nilfs_segment_summary *raw_sum; void *kaddr; u32 crc; bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head, b_assoc_buffers); raw_sum = (struct nilfs_segment_summary *)bh->b_data; crc = crc32_le(seed, (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum), bh->b_size - sizeof(raw_sum->ss_datasum)); list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) { crc = crc32_le(crc, bh->b_data, bh->b_size); } list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { kaddr = kmap_atomic(bh->b_page, KM_USER0); crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size); kunmap_atomic(kaddr, KM_USER0); } raw_sum->ss_datasum = cpu_to_le32(crc); } void nilfs_release_buffers(struct list_head *list) { struct buffer_head *bh, *n; list_for_each_entry_safe(bh, n, list, b_assoc_buffers) { list_del_init(&bh->b_assoc_buffers); if (buffer_nilfs_allocated(bh)) { struct page *clone_page = bh->b_page; /* remove clone page */ brelse(bh); page_cache_release(clone_page); /* for each bh */ if (page_count(clone_page) <= 2) { lock_page(clone_page); nilfs_free_private_page(clone_page); } continue; } brelse(bh); } } /* * BIO operations */ static void nilfs_end_bio_write(struct bio *bio, int err) { const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct nilfs_write_info *wi = bio->bi_private; if (err == -EOPNOTSUPP) { set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); bio_put(bio); /* to be detected by submit_seg_bio() */ } if (!uptodate) atomic_inc(&wi->err); bio_put(bio); complete(&wi->bio_event); } static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode) { struct bio *bio = wi->bio; int err; if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) { wait_for_completion(&wi->bio_event); wi->nbio--; if (unlikely(atomic_read(&wi->err))) { bio_put(bio); err = -EIO; goto failed; } } bio->bi_end_io = nilfs_end_bio_write; bio->bi_private = wi; bio_get(bio); submit_bio(mode, bio); if (bio_flagged(bio, BIO_EOPNOTSUPP)) { bio_put(bio); err = -EOPNOTSUPP; goto failed; } wi->nbio++; bio_put(bio); wi->bio = NULL; wi->rest_blocks -= wi->end - wi->start; wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); wi->start = wi->end; return 0; failed: wi->bio = NULL; return err; } /** * nilfs_alloc_seg_bio - allocate a bio for writing segment. * @sb: super block * @start: beginning disk block number of this BIO. * @nr_vecs: request size of page vector. * * alloc_seg_bio() allocates a new BIO structure and initialize it. * * Return Value: On success, pointer to the struct bio is returned. * On error, NULL is returned. */ static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start, int nr_vecs) { struct bio *bio; bio = bio_alloc(GFP_NOWAIT, nr_vecs); if (bio == NULL) { while (!bio && (nr_vecs >>= 1)) bio = bio_alloc(GFP_NOWAIT, nr_vecs); } if (likely(bio)) { bio->bi_bdev = sb->s_bdev; bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9); } return bio; } void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf, struct nilfs_write_info *wi) { wi->bio = NULL; wi->rest_blocks = segbuf->sb_sum.nblocks; wi->max_pages = bio_get_nr_vecs(wi->sb->s_bdev); wi->nr_vecs = min(wi->max_pages, wi->rest_blocks); wi->start = wi->end = 0; wi->nbio = 0; wi->blocknr = segbuf->sb_pseg_start; atomic_set(&wi->err, 0); init_completion(&wi->bio_event); } static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh, int mode) { int len, err; BUG_ON(wi->nr_vecs <= 0); repeat: if (!wi->bio) { wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end, wi->nr_vecs); if (unlikely(!wi->bio)) return -ENOMEM; } len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh)); if (len == bh->b_size) { wi->end++; return 0; } /* bio is FULL */ err = nilfs_submit_seg_bio(wi, mode); /* never submit current bh */ if (likely(!err)) goto repeat; return err; } int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf, struct nilfs_write_info *wi) { struct buffer_head *bh; int res, rw = WRITE; list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) { res = nilfs_submit_bh(wi, bh, rw); if (unlikely(res)) goto failed_bio; } list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) { res = nilfs_submit_bh(wi, bh, rw); if (unlikely(res)) goto failed_bio; } if (wi->bio) { /* * Last BIO is always sent through the following * submission. */ rw |= (1 << BIO_RW_SYNCIO); res = nilfs_submit_seg_bio(wi, rw); if (unlikely(res)) goto failed_bio; } res = 0; out: return res; failed_bio: atomic_inc(&wi->err); goto out; } /** * nilfs_segbuf_wait - wait for completion of requested BIOs * @wi: nilfs_write_info * * Return Value: On Success, 0 is returned. On Error, one of the following * negative error code is returned. * * %-EIO - I/O error */ int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf, struct nilfs_write_info *wi) { int err = 0; if (!wi->nbio) return 0; do { wait_for_completion(&wi->bio_event); } while (--wi->nbio > 0); if (unlikely(atomic_read(&wi->err) > 0)) { printk(KERN_ERR "NILFS: IO error writing segment\n"); err = -EIO; segbuf->sb_io_error = 1; } return err; }