From 5db53f3e80dee2d9dff5e534f9e9fe1db17c9936 Mon Sep 17 00:00:00 2001 From: Joern Engel Date: Fri, 20 Nov 2009 20:13:39 +0100 Subject: [LogFS] add new flash file system This is a new flash file system. See Documentation/filesystems/logfs.txt Signed-off-by: Joern Engel --- fs/logfs/segment.c | 924 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 924 insertions(+) create mode 100644 fs/logfs/segment.c (limited to 'fs/logfs/segment.c') diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c new file mode 100644 index 0000000..5f58b74 --- /dev/null +++ b/fs/logfs/segment.c @@ -0,0 +1,924 @@ +/* + * fs/logfs/segment.c - Handling the Object Store + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel + * + * Object store or ostore makes up the complete device with exception of + * the superblock and journal areas. Apart from its own metadata it stores + * three kinds of objects: inodes, dentries and blocks, both data and indirect. + */ +#include "logfs.h" + +static int logfs_mark_segment_bad(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + struct btree_head32 *head = &super->s_reserved_segments; + int err; + + err = btree_insert32(head, segno, (void *)1, GFP_NOFS); + if (err) + return err; + logfs_super(sb)->s_bad_segments++; + /* FIXME: write to journal */ + return 0; +} + +int logfs_erase_segment(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + + super->s_gec++; + + return super->s_devops->erase(sb, (u64)segno << super->s_segshift, + super->s_segsize); +} + +static s64 logfs_get_free_bytes(struct logfs_area *area, size_t bytes) +{ + s32 ofs; + + logfs_open_area(area, bytes); + + ofs = area->a_used_bytes; + area->a_used_bytes += bytes; + BUG_ON(area->a_used_bytes >= logfs_super(area->a_sb)->s_segsize); + + return dev_ofs(area->a_sb, area->a_segno, ofs); +} + +static struct page *get_mapping_page(struct super_block *sb, pgoff_t index, + int use_filler) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + filler_t *filler = super->s_devops->readpage; + struct page *page; + + BUG_ON(mapping_gfp_mask(mapping) & __GFP_FS); + if (use_filler) + page = read_cache_page(mapping, index, filler, sb); + else { + page = find_or_create_page(mapping, index, GFP_NOFS); + unlock_page(page); + } + return page; +} + +void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len, + int use_filler) +{ + pgoff_t index = ofs >> PAGE_SHIFT; + struct page *page; + long offset = ofs & (PAGE_SIZE-1); + long copylen; + + /* Only logfs_wbuf_recover may use len==0 */ + BUG_ON(!len && !use_filler); + do { + copylen = min((ulong)len, PAGE_SIZE - offset); + + page = get_mapping_page(area->a_sb, index, use_filler); + SetPageUptodate(page); + BUG_ON(!page); /* FIXME: reserve a pool */ + memcpy(page_address(page) + offset, buf, copylen); + SetPagePrivate(page); + page_cache_release(page); + + buf += copylen; + len -= copylen; + offset = 0; + index++; + } while (len); +} + +/* + * bdev_writeseg will write full pages. Memset the tail to prevent data leaks. + */ +static void pad_wbuf(struct logfs_area *area, int final) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + struct page *page; + u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes); + pgoff_t index = ofs >> PAGE_SHIFT; + long offset = ofs & (PAGE_SIZE-1); + u32 len = PAGE_SIZE - offset; + + if (len == PAGE_SIZE) { + /* The math in this function can surely use some love */ + len = 0; + } + if (len) { + BUG_ON(area->a_used_bytes >= super->s_segsize); + + page = get_mapping_page(area->a_sb, index, 0); + BUG_ON(!page); /* FIXME: reserve a pool */ + memset(page_address(page) + offset, 0xff, len); + SetPagePrivate(page); + page_cache_release(page); + } + + if (!final) + return; + + area->a_used_bytes += len; + for ( ; area->a_used_bytes < super->s_segsize; + area->a_used_bytes += PAGE_SIZE) { + /* Memset another page */ + index++; + page = get_mapping_page(area->a_sb, index, 0); + BUG_ON(!page); /* FIXME: reserve a pool */ + memset(page_address(page), 0xff, PAGE_SIZE); + SetPagePrivate(page); + page_cache_release(page); + } +} + +/* + * We have to be careful with the alias tree. Since lookup is done by bix, + * it needs to be normalized, so 14, 15, 16, etc. all match when dealing with + * indirect blocks. So always use it through accessor functions. + */ +static void *alias_tree_lookup(struct super_block *sb, u64 ino, u64 bix, + level_t level) +{ + struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree; + pgoff_t index = logfs_pack_index(bix, level); + + return btree_lookup128(head, ino, index); +} + +static int alias_tree_insert(struct super_block *sb, u64 ino, u64 bix, + level_t level, void *val) +{ + struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree; + pgoff_t index = logfs_pack_index(bix, level); + + return btree_insert128(head, ino, index, val, GFP_NOFS); +} + +static int btree_write_alias(struct super_block *sb, struct logfs_block *block, + write_alias_t *write_one_alias) +{ + struct object_alias_item *item; + int err; + + list_for_each_entry(item, &block->item_list, list) { + err = write_alias_journal(sb, block->ino, block->bix, + block->level, item->child_no, item->val); + if (err) + return err; + } + return 0; +} + +static gc_level_t btree_block_level(struct logfs_block *block) +{ + return expand_level(block->ino, block->level); +} + +static struct logfs_block_ops btree_block_ops = { + .write_block = btree_write_block, + .block_level = btree_block_level, + .free_block = __free_block, + .write_alias = btree_write_alias, +}; + +int logfs_load_object_aliases(struct super_block *sb, + struct logfs_obj_alias *oa, int count) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_block *block; + struct object_alias_item *item; + u64 ino, bix; + level_t level; + int i, err; + + super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS; + count /= sizeof(*oa); + for (i = 0; i < count; i++) { + item = mempool_alloc(super->s_alias_pool, GFP_NOFS); + if (!item) + return -ENOMEM; + memset(item, 0, sizeof(*item)); + + super->s_no_object_aliases++; + item->val = oa[i].val; + item->child_no = be16_to_cpu(oa[i].child_no); + + ino = be64_to_cpu(oa[i].ino); + bix = be64_to_cpu(oa[i].bix); + level = LEVEL(oa[i].level); + + log_aliases("logfs_load_object_aliases(%llx, %llx, %x, %x) %llx\n", + ino, bix, level, item->child_no, + be64_to_cpu(item->val)); + block = alias_tree_lookup(sb, ino, bix, level); + if (!block) { + block = __alloc_block(sb, ino, bix, level); + block->ops = &btree_block_ops; + err = alias_tree_insert(sb, ino, bix, level, block); + BUG_ON(err); /* mempool empty */ + } + if (test_and_set_bit(item->child_no, block->alias_map)) { + printk(KERN_ERR"LogFS: Alias collision detected\n"); + return -EIO; + } + list_move_tail(&block->alias_list, &super->s_object_alias); + list_add(&item->list, &block->item_list); + } + return 0; +} + +static void kill_alias(void *_block, unsigned long ignore0, + u64 ignore1, u64 ignore2, size_t ignore3) +{ + struct logfs_block *block = _block; + struct super_block *sb = block->sb; + struct logfs_super *super = logfs_super(sb); + struct object_alias_item *item; + + while (!list_empty(&block->item_list)) { + item = list_entry(block->item_list.next, typeof(*item), list); + list_del(&item->list); + mempool_free(item, super->s_alias_pool); + } + block->ops->free_block(sb, block); +} + +static int obj_type(struct inode *inode, level_t level) +{ + if (level == 0) { + if (S_ISDIR(inode->i_mode)) + return OBJ_DENTRY; + if (inode->i_ino == LOGFS_INO_MASTER) + return OBJ_INODE; + } + return OBJ_BLOCK; +} + +static int obj_len(struct super_block *sb, int obj_type) +{ + switch (obj_type) { + case OBJ_DENTRY: + return sizeof(struct logfs_disk_dentry); + case OBJ_INODE: + return sizeof(struct logfs_disk_inode); + case OBJ_BLOCK: + return sb->s_blocksize; + default: + BUG(); + } +} + +static int __logfs_segment_write(struct inode *inode, void *buf, + struct logfs_shadow *shadow, int type, int len, int compr) +{ + struct logfs_area *area; + struct super_block *sb = inode->i_sb; + s64 ofs; + struct logfs_object_header h; + int acc_len; + + if (shadow->gc_level == 0) + acc_len = len; + else + acc_len = obj_len(sb, type); + + area = get_area(sb, shadow->gc_level); + ofs = logfs_get_free_bytes(area, len + LOGFS_OBJECT_HEADERSIZE); + LOGFS_BUG_ON(ofs <= 0, sb); + /* + * Order is important. logfs_get_free_bytes(), by modifying the + * segment file, may modify the content of the very page we're about + * to write now. Which is fine, as long as the calculated crc and + * written data still match. So do the modifications _before_ + * calculating the crc. + */ + + h.len = cpu_to_be16(len); + h.type = type; + h.compr = compr; + h.ino = cpu_to_be64(inode->i_ino); + h.bix = cpu_to_be64(shadow->bix); + h.crc = logfs_crc32(&h, sizeof(h) - 4, 4); + h.data_crc = logfs_crc32(buf, len, 0); + + logfs_buf_write(area, ofs, &h, sizeof(h)); + logfs_buf_write(area, ofs + LOGFS_OBJECT_HEADERSIZE, buf, len); + + shadow->new_ofs = ofs; + shadow->new_len = acc_len + LOGFS_OBJECT_HEADERSIZE; + + return 0; +} + +static s64 logfs_segment_write_compress(struct inode *inode, void *buf, + struct logfs_shadow *shadow, int type, int len) +{ + struct super_block *sb = inode->i_sb; + void *compressor_buf = logfs_super(sb)->s_compressed_je; + ssize_t compr_len; + int ret; + + mutex_lock(&logfs_super(sb)->s_journal_mutex); + compr_len = logfs_compress(buf, compressor_buf, len, len); + + if (compr_len >= 0) { + ret = __logfs_segment_write(inode, compressor_buf, shadow, + type, compr_len, COMPR_ZLIB); + } else { + ret = __logfs_segment_write(inode, buf, shadow, type, len, + COMPR_NONE); + } + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + return ret; +} + +/** + * logfs_segment_write - write data block to object store + * @inode: inode containing data + * + * Returns an errno or zero. + */ +int logfs_segment_write(struct inode *inode, struct page *page, + struct logfs_shadow *shadow) +{ + struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); + int do_compress, type, len; + int ret; + void *buf; + + BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN); + do_compress = logfs_inode(inode)->li_flags & LOGFS_IF_COMPRESSED; + if (shadow->gc_level != 0) { + /* temporarily disable compression for indirect blocks */ + do_compress = 0; + } + + type = obj_type(inode, shrink_level(shadow->gc_level)); + len = obj_len(sb, type); + buf = kmap(page); + if (do_compress) + ret = logfs_segment_write_compress(inode, buf, shadow, type, + len); + else + ret = __logfs_segment_write(inode, buf, shadow, type, len, + COMPR_NONE); + kunmap(page); + + log_segment("logfs_segment_write(%llx, %llx, %x) %llx->%llx %x->%x\n", + shadow->ino, shadow->bix, shadow->gc_level, + shadow->old_ofs, shadow->new_ofs, + shadow->old_len, shadow->new_len); + /* this BUG_ON did catch a locking bug. useful */ + BUG_ON(!(shadow->new_ofs & (super->s_segsize - 1))); + return ret; +} + +int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf) +{ + pgoff_t index = ofs >> PAGE_SHIFT; + struct page *page; + long offset = ofs & (PAGE_SIZE-1); + long copylen; + + while (len) { + copylen = min((ulong)len, PAGE_SIZE - offset); + + page = get_mapping_page(sb, index, 1); + if (IS_ERR(page)) + return PTR_ERR(page); + memcpy(buf, page_address(page) + offset, copylen); + page_cache_release(page); + + buf += copylen; + len -= copylen; + offset = 0; + index++; + } + return 0; +} + +/* + * The "position" of indirect blocks is ambiguous. It can be the position + * of any data block somewhere behind this indirect block. So we need to + * normalize the positions through logfs_block_mask() before comparing. + */ +static int check_pos(struct super_block *sb, u64 pos1, u64 pos2, level_t level) +{ + return (pos1 & logfs_block_mask(sb, level)) != + (pos2 & logfs_block_mask(sb, level)); +} + +#if 0 +static int read_seg_header(struct super_block *sb, u64 ofs, + struct logfs_segment_header *sh) +{ + __be32 crc; + int err; + + err = wbuf_read(sb, ofs, sizeof(*sh), sh); + if (err) + return err; + crc = logfs_crc32(sh, sizeof(*sh), 4); + if (crc != sh->crc) { + printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, " + "got %x\n", ofs, be32_to_cpu(sh->crc), + be32_to_cpu(crc)); + return -EIO; + } + return 0; +} +#endif + +static int read_obj_header(struct super_block *sb, u64 ofs, + struct logfs_object_header *oh) +{ + __be32 crc; + int err; + + err = wbuf_read(sb, ofs, sizeof(*oh), oh); + if (err) + return err; + crc = logfs_crc32(oh, sizeof(*oh) - 4, 4); + if (crc != oh->crc) { + printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, " + "got %x\n", ofs, be32_to_cpu(oh->crc), + be32_to_cpu(crc)); + return -EIO; + } + return 0; +} + +static void move_btree_to_page(struct inode *inode, struct page *page, + __be64 *data) +{ + struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); + struct btree_head128 *head = &super->s_object_alias_tree; + struct logfs_block *block; + struct object_alias_item *item, *next; + + if (!(super->s_flags & LOGFS_SB_FLAG_OBJ_ALIAS)) + return; + + block = btree_remove128(head, inode->i_ino, page->index); + if (!block) + return; + + log_blockmove("move_btree_to_page(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + list_for_each_entry_safe(item, next, &block->item_list, list) { + data[item->child_no] = item->val; + list_del(&item->list); + mempool_free(item, super->s_alias_pool); + } + block->page = page; + SetPagePrivate(page); + page->private = (unsigned long)block; + block->ops = &indirect_block_ops; + initialize_block_counters(page, block, data, 0); +} + +/* + * This silences a false, yet annoying gcc warning. I hate it when my editor + * jumps into bitops.h each time I recompile this file. + * TODO: Complain to gcc folks about this and upgrade compiler. + */ +static unsigned long fnb(const unsigned long *addr, + unsigned long size, unsigned long offset) +{ + return find_next_bit(addr, size, offset); +} + +void move_page_to_btree(struct page *page) +{ + struct logfs_block *block = logfs_block(page); + struct super_block *sb = block->sb; + struct logfs_super *super = logfs_super(sb); + struct object_alias_item *item; + unsigned long pos; + __be64 *child; + int err; + + if (super->s_flags & LOGFS_SB_FLAG_SHUTDOWN) { + block->ops->free_block(sb, block); + return; + } + log_blockmove("move_page_to_btree(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS; + + for (pos = 0; ; pos++) { + pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos); + if (pos >= LOGFS_BLOCK_FACTOR) + break; + + item = mempool_alloc(super->s_alias_pool, GFP_NOFS); + BUG_ON(!item); /* mempool empty */ + memset(item, 0, sizeof(*item)); + + child = kmap_atomic(page, KM_USER0); + item->val = child[pos]; + kunmap_atomic(child, KM_USER0); + item->child_no = pos; + list_add(&item->list, &block->item_list); + } + block->page = NULL; + ClearPagePrivate(page); + page->private = 0; + block->ops = &btree_block_ops; + err = alias_tree_insert(block->sb, block->ino, block->bix, block->level, + block); + BUG_ON(err); /* mempool empty */ + ClearPageUptodate(page); +} + +static int __logfs_segment_read(struct inode *inode, void *buf, + u64 ofs, u64 bix, level_t level) +{ + struct super_block *sb = inode->i_sb; + void *compressor_buf = logfs_super(sb)->s_compressed_je; + struct logfs_object_header oh; + __be32 crc; + u16 len; + int err, block_len; + + block_len = obj_len(sb, obj_type(inode, level)); + err = read_obj_header(sb, ofs, &oh); + if (err) + goto out_err; + + err = -EIO; + if (be64_to_cpu(oh.ino) != inode->i_ino + || check_pos(sb, be64_to_cpu(oh.bix), bix, level)) { + printk(KERN_ERR"LOGFS: (ino, bix) don't match at %llx: " + "expected (%lx, %llx), got (%llx, %llx)\n", + ofs, inode->i_ino, bix, + be64_to_cpu(oh.ino), be64_to_cpu(oh.bix)); + goto out_err; + } + + len = be16_to_cpu(oh.len); + + switch (oh.compr) { + case COMPR_NONE: + err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len, buf); + if (err) + goto out_err; + crc = logfs_crc32(buf, len, 0); + if (crc != oh.data_crc) { + printk(KERN_ERR"LOGFS: uncompressed data crc error at " + "%llx: expected %x, got %x\n", ofs, + be32_to_cpu(oh.data_crc), + be32_to_cpu(crc)); + goto out_err; + } + break; + case COMPR_ZLIB: + mutex_lock(&logfs_super(sb)->s_journal_mutex); + err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len, + compressor_buf); + if (err) { + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + goto out_err; + } + crc = logfs_crc32(compressor_buf, len, 0); + if (crc != oh.data_crc) { + printk(KERN_ERR"LOGFS: compressed data crc error at " + "%llx: expected %x, got %x\n", ofs, + be32_to_cpu(oh.data_crc), + be32_to_cpu(crc)); + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + goto out_err; + } + err = logfs_uncompress(compressor_buf, buf, len, block_len); + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + if (err) { + printk(KERN_ERR"LOGFS: uncompress error at %llx\n", ofs); + goto out_err; + } + break; + default: + LOGFS_BUG(sb); + err = -EIO; + goto out_err; + } + return 0; + +out_err: + logfs_set_ro(sb); + printk(KERN_ERR"LOGFS: device is read-only now\n"); + LOGFS_BUG(sb); + return err; +} + +/** + * logfs_segment_read - read data block from object store + * @inode: inode containing data + * @buf: data buffer + * @ofs: physical data offset + * @bix: block index + * @level: block level + * + * Returns 0 on success or a negative errno. + */ +int logfs_segment_read(struct inode *inode, struct page *page, + u64 ofs, u64 bix, level_t level) +{ + int err; + void *buf; + + if (PageUptodate(page)) + return 0; + + ofs &= ~LOGFS_FULLY_POPULATED; + + buf = kmap(page); + err = __logfs_segment_read(inode, buf, ofs, bix, level); + if (!err) { + move_btree_to_page(inode, page, buf); + SetPageUptodate(page); + } + kunmap(page); + log_segment("logfs_segment_read(%lx, %llx, %x) %llx (%d)\n", + inode->i_ino, bix, level, ofs, err); + return err; +} + +int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow) +{ + struct super_block *sb = inode->i_sb; + struct logfs_object_header h; + u16 len; + int err; + + BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN); + BUG_ON(shadow->old_ofs & LOGFS_FULLY_POPULATED); + if (!shadow->old_ofs) + return 0; + + log_segment("logfs_segment_delete(%llx, %llx, %x) %llx->%llx %x->%x\n", + shadow->ino, shadow->bix, shadow->gc_level, + shadow->old_ofs, shadow->new_ofs, + shadow->old_len, shadow->new_len); + err = read_obj_header(sb, shadow->old_ofs, &h); + LOGFS_BUG_ON(err, sb); + LOGFS_BUG_ON(be64_to_cpu(h.ino) != inode->i_ino, sb); + LOGFS_BUG_ON(check_pos(sb, shadow->bix, be64_to_cpu(h.bix), + shrink_level(shadow->gc_level)), sb); + + if (shadow->gc_level == 0) + len = be16_to_cpu(h.len); + else + len = obj_len(sb, h.type); + shadow->old_len = len + sizeof(h); + return 0; +} + +static void freeseg(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + struct page *page; + u64 ofs, start, end; + + start = dev_ofs(sb, segno, 0); + end = dev_ofs(sb, segno + 1, 0); + for (ofs = start; ofs < end; ofs += PAGE_SIZE) { + page = find_get_page(mapping, ofs >> PAGE_SHIFT); + if (!page) + continue; + ClearPagePrivate(page); + page_cache_release(page); + } +} + +int logfs_open_area(struct logfs_area *area, size_t bytes) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + int err, closed = 0; + + if (area->a_is_open && area->a_used_bytes + bytes <= super->s_segsize) + return 0; + + if (area->a_is_open) { + u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes); + u32 len = super->s_segsize - area->a_written_bytes; + + log_gc("logfs_close_area(%x)\n", area->a_segno); + pad_wbuf(area, 1); + super->s_devops->writeseg(area->a_sb, ofs, len); + freeseg(sb, area->a_segno); + closed = 1; + } + + area->a_used_bytes = 0; + area->a_written_bytes = 0; +again: + area->a_ops->get_free_segment(area); + area->a_ops->get_erase_count(area); + + log_gc("logfs_open_area(%x, %x)\n", area->a_segno, area->a_level); + err = area->a_ops->erase_segment(area); + if (err) { + printk(KERN_WARNING "LogFS: Error erasing segment %x\n", + area->a_segno); + logfs_mark_segment_bad(sb, area->a_segno); + goto again; + } + area->a_is_open = 1; + return closed; +} + +void logfs_sync_area(struct logfs_area *area) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes); + u32 len = (area->a_used_bytes - area->a_written_bytes); + + if (super->s_writesize) + len &= ~(super->s_writesize - 1); + if (len == 0) + return; + pad_wbuf(area, 0); + super->s_devops->writeseg(sb, ofs, len); + area->a_written_bytes += len; +} + +void logfs_sync_segments(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i; + + for_each_area(i) + logfs_sync_area(super->s_area[i]); +} + +/* + * Pick a free segment to be used for this area. Effectively takes a + * candidate from the free list (not really a candidate anymore). + */ +static void ostore_get_free_segment(struct logfs_area *area) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + + if (super->s_free_list.count == 0) { + printk(KERN_ERR"LOGFS: ran out of free segments\n"); + LOGFS_BUG(sb); + } + + area->a_segno = get_best_cand(sb, &super->s_free_list, NULL); +} + +static void ostore_get_erase_count(struct logfs_area *area) +{ + struct logfs_segment_entry se; + u32 ec_level; + + logfs_get_segment_entry(area->a_sb, area->a_segno, &se); + BUG_ON(se.ec_level == cpu_to_be32(BADSEG) || + se.valid == cpu_to_be32(RESERVED)); + + ec_level = be32_to_cpu(se.ec_level); + area->a_erase_count = (ec_level >> 4) + 1; +} + +static int ostore_erase_segment(struct logfs_area *area) +{ + struct super_block *sb = area->a_sb; + struct logfs_segment_header sh; + u64 ofs; + int err; + + err = logfs_erase_segment(sb, area->a_segno); + if (err) + return err; + + sh.pad = 0; + sh.type = SEG_OSTORE; + sh.level = (__force u8)area->a_level; + sh.segno = cpu_to_be32(area->a_segno); + sh.ec = cpu_to_be32(area->a_erase_count); + sh.gec = cpu_to_be64(logfs_super(sb)->s_gec); + sh.crc = logfs_crc32(&sh, sizeof(sh), 4); + + logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count, + area->a_level); + + ofs = dev_ofs(sb, area->a_segno, 0); + area->a_used_bytes = sizeof(sh); + logfs_buf_write(area, ofs, &sh, sizeof(sh)); + return 0; +} + +static const struct logfs_area_ops ostore_area_ops = { + .get_free_segment = ostore_get_free_segment, + .get_erase_count = ostore_get_erase_count, + .erase_segment = ostore_erase_segment, +}; + +static void free_area(struct logfs_area *area) +{ + if (area) + freeseg(area->a_sb, area->a_segno); + kfree(area); +} + +static struct logfs_area *alloc_area(struct super_block *sb) +{ + struct logfs_area *area; + + area = kzalloc(sizeof(*area), GFP_KERNEL); + if (!area) + return NULL; + + area->a_sb = sb; + return area; +} + +static void map_invalidatepage(struct page *page, unsigned long l) +{ + BUG(); +} + +static int map_releasepage(struct page *page, gfp_t g) +{ + /* Don't release these pages */ + return 0; +} + +static const struct address_space_operations mapping_aops = { + .invalidatepage = map_invalidatepage, + .releasepage = map_releasepage, + .set_page_dirty = __set_page_dirty_nobuffers, +}; + +int logfs_init_mapping(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping; + struct inode *inode; + + inode = logfs_new_meta_inode(sb, LOGFS_INO_MAPPING); + if (IS_ERR(inode)) + return PTR_ERR(inode); + super->s_mapping_inode = inode; + mapping = inode->i_mapping; + mapping->a_ops = &mapping_aops; + /* Would it be possible to use __GFP_HIGHMEM as well? */ + mapping_set_gfp_mask(mapping, GFP_NOFS); + return 0; +} + +int logfs_init_areas(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i = -1; + + super->s_alias_pool = mempool_create_kmalloc_pool(600, + sizeof(struct object_alias_item)); + if (!super->s_alias_pool) + return -ENOMEM; + + super->s_journal_area = alloc_area(sb); + if (!super->s_journal_area) + goto err; + + for_each_area(i) { + super->s_area[i] = alloc_area(sb); + if (!super->s_area[i]) + goto err; + super->s_area[i]->a_level = GC_LEVEL(i); + super->s_area[i]->a_ops = &ostore_area_ops; + } + btree_init_mempool128(&super->s_object_alias_tree, + super->s_btree_pool); + return 0; + +err: + for (i--; i >= 0; i--) + free_area(super->s_area[i]); + free_area(super->s_journal_area); + mempool_destroy(super->s_alias_pool); + return -ENOMEM; +} + +void logfs_cleanup_areas(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i; + + btree_grim_visitor128(&super->s_object_alias_tree, 0, kill_alias); + for_each_area(i) + free_area(super->s_area[i]); + free_area(super->s_journal_area); + destroy_meta_inode(super->s_mapping_inode); +} -- cgit v1.1 From 9421502b4fc894cc477be8fc49776830e37ca157 Mon Sep 17 00:00:00 2001 From: Joern Engel Date: Thu, 4 Mar 2010 21:30:58 +0100 Subject: [LogFS] Fix bdev erases Erases for block devices were always just emulated by writing 0xff. Some time back the write was removed and only the page cache was changed to 0xff. Superficialy a good idea with two problems: 1. Touching the page cache isn't necessary either. 2. However, writing out 0xff _is_ necessary for the journal. As the journal is scanned linearly, an old non-overwritten commit entry can be used on next mount and cause havoc. This should fix both aspects. --- fs/logfs/segment.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/logfs/segment.c') diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c index 5f58b74..664cd0d 100644 --- a/fs/logfs/segment.c +++ b/fs/logfs/segment.c @@ -25,14 +25,14 @@ static int logfs_mark_segment_bad(struct super_block *sb, u32 segno) return 0; } -int logfs_erase_segment(struct super_block *sb, u32 segno) +int logfs_erase_segment(struct super_block *sb, u32 segno, int ensure_erase) { struct logfs_super *super = logfs_super(sb); super->s_gec++; return super->s_devops->erase(sb, (u64)segno << super->s_segshift, - super->s_segsize); + super->s_segsize, ensure_erase); } static s64 logfs_get_free_bytes(struct logfs_area *area, size_t bytes) @@ -798,7 +798,7 @@ static int ostore_erase_segment(struct logfs_area *area) u64 ofs; int err; - err = logfs_erase_segment(sb, area->a_segno); + err = logfs_erase_segment(sb, area->a_segno, 0); if (err) return err; -- cgit v1.1 From c6d3830140f1d56b07d8ab56a6e14ca3c492a39a Mon Sep 17 00:00:00 2001 From: Joern Engel Date: Thu, 4 Mar 2010 21:36:19 +0100 Subject: [LogFS] Only write journal if dirty This prevents unnecessary journal writes. More importantly it prevents an oops due to a journal write on failed mount. --- fs/logfs/segment.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'fs/logfs/segment.c') diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c index 664cd0d..1a14f99 100644 --- a/fs/logfs/segment.c +++ b/fs/logfs/segment.c @@ -352,7 +352,8 @@ int logfs_segment_write(struct inode *inode, struct page *page, int ret; void *buf; - BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN); + super->s_flags |= LOGFS_SB_FLAG_DIRTY; + BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN); do_compress = logfs_inode(inode)->li_flags & LOGFS_IF_COMPRESSED; if (shadow->gc_level != 0) { /* temporarily disable compression for indirect blocks */ @@ -653,11 +654,13 @@ int logfs_segment_read(struct inode *inode, struct page *page, int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow) { struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); struct logfs_object_header h; u16 len; int err; - BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN); + super->s_flags |= LOGFS_SB_FLAG_DIRTY; + BUG_ON(super->s_flags & LOGFS_SB_FLAG_SHUTDOWN); BUG_ON(shadow->old_ofs & LOGFS_FULLY_POPULATED); if (!shadow->old_ofs) return 0; -- cgit v1.1