diff options
Diffstat (limited to 'fs/logfs/super.c')
| -rw-r--r-- | fs/logfs/super.c | 650 |
1 files changed, 650 insertions, 0 deletions
diff --git a/fs/logfs/super.c b/fs/logfs/super.c new file mode 100644 index 00000000000..c66beab78de --- /dev/null +++ b/fs/logfs/super.c @@ -0,0 +1,650 @@ +/* + * 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/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; + 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 write_one_sb(sb, super->s_devops->find_last_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; + + /* 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; + + err = logfs_open_segfile(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 vfsmount *mnt) +{ + 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) + goto fail; + + super->s_erase_page = alloc_pages(GFP_KERNEL, 0); + if (!super->s_erase_page) + goto fail2; + memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE); + + /* FIXME: check for read-only mounts */ + err = logfs_make_writeable(sb); + if (err) + goto fail3; + + log_super("LogFS: Finished mounting\n"); + simple_set_mnt(mnt, sb); + return 0; + +fail3: + __free_page(super->s_erase_page); +fail2: + iput(rootdir); +fail: + iput(logfs_super(sb)->s_master_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(first)) { + 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 -EIO; + + 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); + + 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(sb); + mempool_destroy(super->s_btree_pool); + mempool_destroy(super->s_alias_pool); + kfree(super); + log_super("LogFS: Finished unmounting\n"); +} + +int logfs_get_sb_device(struct file_system_type *type, int flags, + struct mtd_info *mtd, struct block_device *bdev, + const struct logfs_device_ops *devops, struct vfsmount *mnt) +{ + struct logfs_super *super; + struct super_block *sb; + int err = -ENOMEM; + static int mount_count; + + log_super("LogFS: Start mount %x\n", mount_count++); + super = kzalloc(sizeof(*super), GFP_KERNEL); + if (!super) + goto err0; + + super->s_mtd = mtd; + super->s_bdev = bdev; + err = -EINVAL; + sb = sget(type, logfs_sb_test, logfs_sb_set, super); + if (IS_ERR(sb)) + goto err0; + + if (sb->s_root) { + /* Device is already in use */ + err = 0; + simple_set_mnt(mnt, sb); + goto err0; + } + + super->s_devops = devops; + + /* + * 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, mnt); + if (err) + goto err1; + return 0; + +err1: + up_write(&sb->s_umount); + deactivate_super(sb); + return err; +err0: + kfree(super); + //devops->put_device(sb); + return err; +} + +static int logfs_get_sb(struct file_system_type *type, int flags, + const char *devname, void *data, struct vfsmount *mnt) +{ + ulong mtdnr; + + if (!devname) + return logfs_get_sb_bdev(type, flags, devname, mnt); + if (strncmp(devname, "mtd", 3)) + return logfs_get_sb_bdev(type, flags, devname, mnt); + + { + char *garbage; + mtdnr = simple_strtoul(devname+3, &garbage, 0); + if (*garbage) + return -EINVAL; + } + + return logfs_get_sb_mtd(type, flags, mtdnr, mnt); +} + +static struct file_system_type logfs_fs_type = { + .owner = THIS_MODULE, + .name = "logfs", + .get_sb = logfs_get_sb, + .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"); |