/* * fs/logfs/super.c * * As should be obvious for Linux kernel code, license is GPLv2 * * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> * * Generally contains mount/umount code and also serves as a dump area for * any functions that don't fit elsewhere and neither justify a file of their * own. */ #include "logfs.h" #include <linux/bio.h> #include <linux/slab.h> #include <linux/blkdev.h> #include <linux/mtd/mtd.h> #include <linux/statfs.h> #include <linux/buffer_head.h> static DEFINE_MUTEX(emergency_mutex); static struct page *emergency_page; struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index) { filler_t *filler = (filler_t *)mapping->a_ops->readpage; struct page *page; int err; page = read_cache_page(mapping, index, filler, NULL); if (page) return page; /* No more pages available, switch to emergency page */ printk(KERN_INFO"Logfs: Using emergency page\n"); mutex_lock(&emergency_mutex); err = filler(NULL, emergency_page); if (err) { mutex_unlock(&emergency_mutex); printk(KERN_EMERG"Logfs: Error reading emergency page\n"); return ERR_PTR(err); } return emergency_page; } void emergency_read_end(struct page *page) { if (page == emergency_page) mutex_unlock(&emergency_mutex); else page_cache_release(page); } static void dump_segfile(struct super_block *sb) { struct logfs_super *super = logfs_super(sb); struct logfs_segment_entry se; u32 segno; for (segno = 0; segno < super->s_no_segs; segno++) { logfs_get_segment_entry(sb, segno, &se); printk("%3x: %6x %8x", segno, be32_to_cpu(se.ec_level), be32_to_cpu(se.valid)); if (++segno < super->s_no_segs) { logfs_get_segment_entry(sb, segno, &se); printk(" %6x %8x", be32_to_cpu(se.ec_level), be32_to_cpu(se.valid)); } if (++segno < super->s_no_segs) { logfs_get_segment_entry(sb, segno, &se); printk(" %6x %8x", be32_to_cpu(se.ec_level), be32_to_cpu(se.valid)); } if (++segno < super->s_no_segs) { logfs_get_segment_entry(sb, segno, &se); printk(" %6x %8x", be32_to_cpu(se.ec_level), be32_to_cpu(se.valid)); } printk("\n"); } } /* * logfs_crash_dump - dump debug information to device * * The LogFS superblock only occupies part of a segment. This function will * write as much debug information as it can gather into the spare space. */ void logfs_crash_dump(struct super_block *sb) { dump_segfile(sb); } /* * TODO: move to lib/string.c */ /** * memchr_inv - Find a character in an area of memory. * @s: The memory area * @c: The byte to search for * @n: The size of the area. * * returns the address of the first character other than @c, or %NULL * if the whole buffer contains just @c. */ void *memchr_inv(const void *s, int c, size_t n) { const unsigned char *p = s; while (n-- != 0) if ((unsigned char)c != *p++) return (void *)(p - 1); return NULL; } /* * FIXME: There should be a reserve for root, similar to ext2. */ int logfs_statfs(struct dentry *dentry, struct kstatfs *stats) { struct super_block *sb = dentry->d_sb; struct logfs_super *super = logfs_super(sb); stats->f_type = LOGFS_MAGIC_U32; stats->f_bsize = sb->s_blocksize; stats->f_blocks = super->s_size >> LOGFS_BLOCK_BITS >> 3; stats->f_bfree = super->s_free_bytes >> sb->s_blocksize_bits; stats->f_bavail = super->s_free_bytes >> sb->s_blocksize_bits; stats->f_files = 0; stats->f_ffree = 0; stats->f_namelen = LOGFS_MAX_NAMELEN; return 0; } static int logfs_sb_set(struct super_block *sb, void *_super) { struct logfs_super *super = _super; sb->s_fs_info = super; sb->s_mtd = super->s_mtd; sb->s_bdev = super->s_bdev; #ifdef CONFIG_BLOCK if (sb->s_bdev) sb->s_bdi = &bdev_get_queue(sb->s_bdev)->backing_dev_info; #endif #ifdef CONFIG_MTD if (sb->s_mtd) sb->s_bdi = sb->s_mtd->backing_dev_info; #endif return 0; } static int logfs_sb_test(struct super_block *sb, void *_super) { struct logfs_super *super = _super; struct mtd_info *mtd = super->s_mtd; if (mtd && sb->s_mtd == mtd) return 1; if (super->s_bdev && sb->s_bdev == super->s_bdev) return 1; return 0; } static void set_segment_header(struct logfs_segment_header *sh, u8 type, u8 level, u32 segno, u32 ec) { sh->pad = 0; sh->type = type; sh->level = level; sh->segno = cpu_to_be32(segno); sh->ec = cpu_to_be32(ec); sh->gec = cpu_to_be64(segno); sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4); } static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds, u32 segno, u32 ec) { struct logfs_super *super = logfs_super(sb); struct logfs_segment_header *sh = &ds->ds_sh; int i; memset(ds, 0, sizeof(*ds)); set_segment_header(sh, SEG_SUPER, 0, segno, ec); ds->ds_ifile_levels = super->s_ifile_levels; ds->ds_iblock_levels = super->s_iblock_levels; ds->ds_data_levels = super->s_data_levels; /* XXX: Remove */ ds->ds_segment_shift = super->s_segshift; ds->ds_block_shift = sb->s_blocksize_bits; ds->ds_write_shift = super->s_writeshift; ds->ds_filesystem_size = cpu_to_be64(super->s_size); ds->ds_segment_size = cpu_to_be32(super->s_segsize); ds->ds_bad_seg_reserve = cpu_to_be32(super->s_bad_seg_reserve); ds->ds_feature_incompat = cpu_to_be64(super->s_feature_incompat); ds->ds_feature_ro_compat= cpu_to_be64(super->s_feature_ro_compat); ds->ds_feature_compat = cpu_to_be64(super->s_feature_compat); ds->ds_feature_flags = cpu_to_be64(super->s_feature_flags); ds->ds_root_reserve = cpu_to_be64(super->s_root_reserve); ds->ds_speed_reserve = cpu_to_be64(super->s_speed_reserve); journal_for_each(i) ds->ds_journal_seg[i] = cpu_to_be32(super->s_journal_seg[i]); ds->ds_magic = cpu_to_be64(LOGFS_MAGIC); ds->ds_crc = logfs_crc32(ds, sizeof(*ds), LOGFS_SEGMENT_HEADERSIZE + 12); } static int write_one_sb(struct super_block *sb, struct page *(*find_sb)(struct super_block *sb, u64 *ofs)) { struct logfs_super *super = logfs_super(sb); struct logfs_disk_super *ds; struct logfs_segment_entry se; struct page *page; u64 ofs; u32 ec, segno; int err; page = find_sb(sb, &ofs); if (!page) return -EIO; ds = page_address(page); segno = seg_no(sb, ofs); logfs_get_segment_entry(sb, segno, &se); ec = be32_to_cpu(se.ec_level) >> 4; ec++; logfs_set_segment_erased(sb, segno, ec, 0); logfs_write_ds(sb, ds, segno, ec); err = super->s_devops->write_sb(sb, page); page_cache_release(page); return err; } int logfs_write_sb(struct super_block *sb) { struct logfs_super *super = logfs_super(sb); int err; /* First superblock */ err = write_one_sb(sb, super->s_devops->find_first_sb); if (err) return err; /* Last superblock */ err = write_one_sb(sb, super->s_devops->find_last_sb); if (err) return err; return 0; } static int ds_cmp(const void *ds0, const void *ds1) { size_t len = sizeof(struct logfs_disk_super); /* We know the segment headers differ, so ignore them */ len -= LOGFS_SEGMENT_HEADERSIZE; ds0 += LOGFS_SEGMENT_HEADERSIZE; ds1 += LOGFS_SEGMENT_HEADERSIZE; return memcmp(ds0, ds1, len); } static int logfs_recover_sb(struct super_block *sb) { struct logfs_super *super = logfs_super(sb); struct logfs_disk_super _ds0, *ds0 = &_ds0; struct logfs_disk_super _ds1, *ds1 = &_ds1; int err, valid0, valid1; /* read first superblock */ err = wbuf_read(sb, super->s_sb_ofs[0], sizeof(*ds0), ds0); if (err) return err; /* read last superblock */ err = wbuf_read(sb, super->s_sb_ofs[1], sizeof(*ds1), ds1); if (err) return err; valid0 = logfs_check_ds(ds0) == 0; valid1 = logfs_check_ds(ds1) == 0; if (!valid0 && valid1) { printk(KERN_INFO"First superblock is invalid - fixing.\n"); return write_one_sb(sb, super->s_devops->find_first_sb); } if (valid0 && !valid1) { printk(KERN_INFO"Last superblock is invalid - fixing.\n"); return write_one_sb(sb, super->s_devops->find_last_sb); } if (valid0 && valid1 && ds_cmp(ds0, ds1)) { printk(KERN_INFO"Superblocks don't match - fixing.\n"); return logfs_write_sb(sb); } /* If neither is valid now, something's wrong. Didn't we properly * check them before?!? */ BUG_ON(!valid0 && !valid1); return 0; } static int logfs_make_writeable(struct super_block *sb) { int err; err = logfs_open_segfile(sb); if (err) return err; /* Repair any broken superblock copies */ err = logfs_recover_sb(sb); if (err) return err; /* Check areas for trailing unaccounted data */ err = logfs_check_areas(sb); if (err) return err; /* Do one GC pass before any data gets dirtied */ logfs_gc_pass(sb); /* after all initializations are done, replay the journal * for rw-mounts, if necessary */ err = logfs_replay_journal(sb); if (err) return err; return 0; } static int logfs_get_sb_final(struct super_block *sb) { struct logfs_super *super = logfs_super(sb); struct inode *rootdir; int err; /* root dir */ rootdir = logfs_iget(sb, LOGFS_INO_ROOT); if (IS_ERR(rootdir)) goto fail; sb->s_root = d_alloc_root(rootdir); if (!sb->s_root) { iput(rootdir); goto fail; } /* at that point we know that ->put_super() will be called */ super->s_erase_page = alloc_pages(GFP_KERNEL, 0); if (!super->s_erase_page) return -ENOMEM; memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE); /* FIXME: check for read-only mounts */ err = logfs_make_writeable(sb); if (err) { __free_page(super->s_erase_page); return err; } log_super("LogFS: Finished mounting\n"); return 0; fail: iput(super->s_master_inode); iput(super->s_segfile_inode); iput(super->s_mapping_inode); return -EIO; } int logfs_check_ds(struct logfs_disk_super *ds) { struct logfs_segment_header *sh = &ds->ds_sh; if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC)) return -EINVAL; if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4)) return -EINVAL; if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds), LOGFS_SEGMENT_HEADERSIZE + 12)) return -EINVAL; return 0; } static struct page *find_super_block(struct super_block *sb) { struct logfs_super *super = logfs_super(sb); struct page *first, *last; first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]); if (!first || IS_ERR(first)) return NULL; last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]); if (!last || IS_ERR(last)) { page_cache_release(first); return NULL; } if (!logfs_check_ds(page_address(first))) { page_cache_release(last); return first; } /* First one didn't work, try the second superblock */ if (!logfs_check_ds(page_address(last))) { page_cache_release(first); return last; } /* Neither worked, sorry folks */ page_cache_release(first); page_cache_release(last); return NULL; } static int __logfs_read_sb(struct super_block *sb) { struct logfs_super *super = logfs_super(sb); struct page *page; struct logfs_disk_super *ds; int i; page = find_super_block(sb); if (!page) return -EINVAL; ds = page_address(page); super->s_size = be64_to_cpu(ds->ds_filesystem_size); super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve); super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve); super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve); super->s_segsize = 1 << ds->ds_segment_shift; super->s_segmask = (1 << ds->ds_segment_shift) - 1; super->s_segshift = ds->ds_segment_shift; sb->s_blocksize = 1 << ds->ds_block_shift; sb->s_blocksize_bits = ds->ds_block_shift; super->s_writesize = 1 << ds->ds_write_shift; super->s_writeshift = ds->ds_write_shift; super->s_no_segs = super->s_size >> super->s_segshift; super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits; super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat); super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat); super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat); super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags); journal_for_each(i) super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]); super->s_ifile_levels = ds->ds_ifile_levels; super->s_iblock_levels = ds->ds_iblock_levels; super->s_data_levels = ds->ds_data_levels; super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels + super->s_data_levels; page_cache_release(page); return 0; } static int logfs_read_sb(struct super_block *sb, int read_only) { struct logfs_super *super = logfs_super(sb); int ret; super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL); if (!super->s_btree_pool) return -ENOMEM; btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool); btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool); btree_init_mempool32(&super->s_shadow_tree.segment_map, super->s_btree_pool); ret = logfs_init_mapping(sb); if (ret) return ret; ret = __logfs_read_sb(sb); if (ret) return ret; if (super->s_feature_incompat & ~LOGFS_FEATURES_INCOMPAT) return -EIO; if ((super->s_feature_ro_compat & ~LOGFS_FEATURES_RO_COMPAT) && !read_only) return -EIO; mutex_init(&super->s_dirop_mutex); mutex_init(&super->s_object_alias_mutex); INIT_LIST_HEAD(&super->s_freeing_list); ret = logfs_init_rw(sb); if (ret) return ret; ret = logfs_init_areas(sb); if (ret) return ret; ret = logfs_init_gc(sb); if (ret) return ret; ret = logfs_init_journal(sb); if (ret) return ret; return 0; } static void logfs_kill_sb(struct super_block *sb) { struct logfs_super *super = logfs_super(sb); log_super("LogFS: Start unmounting\n"); /* Alias entries slow down mount, so evict as many as possible */ sync_filesystem(sb); logfs_write_anchor(sb); /* * From this point on alias entries are simply dropped - and any * writes to the object store are considered bugs. */ super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN; log_super("LogFS: Now in shutdown\n"); generic_shutdown_super(sb); BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes); logfs_cleanup_gc(sb); logfs_cleanup_journal(sb); logfs_cleanup_areas(sb); logfs_cleanup_rw(sb); if (super->s_erase_page) __free_page(super->s_erase_page); super->s_devops->put_device(super); logfs_mempool_destroy(super->s_btree_pool); logfs_mempool_destroy(super->s_alias_pool); kfree(super); log_super("LogFS: Finished unmounting\n"); } static struct dentry *logfs_get_sb_device(struct logfs_super *super, struct file_system_type *type, int flags) { struct super_block *sb; int err = -ENOMEM; static int mount_count; log_super("LogFS: Start mount %x\n", mount_count++); err = -EINVAL; sb = sget(type, logfs_sb_test, logfs_sb_set, super); if (IS_ERR(sb)) { super->s_devops->put_device(super); kfree(super); return ERR_CAST(sb); } if (sb->s_root) { /* Device is already in use */ super->s_devops->put_device(super); kfree(super); return dget(sb->s_root); } /* * sb->s_maxbytes is limited to 8TB. On 32bit systems, the page cache * only covers 16TB and the upper 8TB are used for indirect blocks. * On 64bit system we could bump up the limit, but that would make * the filesystem incompatible with 32bit systems. */ sb->s_maxbytes = (1ull << 43) - 1; sb->s_op = &logfs_super_operations; sb->s_flags = flags | MS_NOATIME; err = logfs_read_sb(sb, sb->s_flags & MS_RDONLY); if (err) goto err1; sb->s_flags |= MS_ACTIVE; err = logfs_get_sb_final(sb); if (err) { deactivate_locked_super(sb); return ERR_PTR(err); } return dget(sb->s_root); err1: /* no ->s_root, no ->put_super() */ iput(super->s_master_inode); iput(super->s_segfile_inode); iput(super->s_mapping_inode); deactivate_locked_super(sb); return ERR_PTR(err); } static struct dentry *logfs_mount(struct file_system_type *type, int flags, const char *devname, void *data) { ulong mtdnr; struct logfs_super *super; int err; super = kzalloc(sizeof(*super), GFP_KERNEL); if (!super) return ERR_PTR(-ENOMEM); if (!devname) err = logfs_get_sb_bdev(super, type, devname); else if (strncmp(devname, "mtd", 3)) err = logfs_get_sb_bdev(super, type, devname); else { char *garbage; mtdnr = simple_strtoul(devname+3, &garbage, 0); if (*garbage) err = -EINVAL; else err = logfs_get_sb_mtd(super, mtdnr); } if (err) { kfree(super); return ERR_PTR(err); } return logfs_get_sb_device(super, type, flags); } static struct file_system_type logfs_fs_type = { .owner = THIS_MODULE, .name = "logfs", .mount = logfs_mount, .kill_sb = logfs_kill_sb, .fs_flags = FS_REQUIRES_DEV, }; static int __init logfs_init(void) { int ret; emergency_page = alloc_pages(GFP_KERNEL, 0); if (!emergency_page) return -ENOMEM; ret = logfs_compr_init(); if (ret) goto out1; ret = logfs_init_inode_cache(); if (ret) goto out2; return register_filesystem(&logfs_fs_type); out2: logfs_compr_exit(); out1: __free_pages(emergency_page, 0); return ret; } static void __exit logfs_exit(void) { unregister_filesystem(&logfs_fs_type); logfs_destroy_inode_cache(); logfs_compr_exit(); __free_pages(emergency_page, 0); } module_init(logfs_init); module_exit(logfs_exit); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Joern Engel <joern@logfs.org>"); MODULE_DESCRIPTION("scalable flash filesystem");