Superblock support functions. Signed-off-by: Renaud Barbier --- fs/ubifs/sb.c | 346 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 346 insertions(+), 0 deletions(-) create mode 100644 fs/ubifs/sb.c diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c new file mode 100644 index 0000000..00c9cd3 --- /dev/null +++ b/fs/ubifs/sb.c @@ -0,0 +1,346 @@ +/* + * This file is part of UBIFS. + * + * Copyright (C) 2006-2008 Nokia Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * 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 + * + * Authors: Artem Bityutskiy (���������������� ����������) + * Adrian Hunter + */ + +/* + * This file implements UBIFS superblock. The superblock is stored at the first + * LEB of the volume and is never changed by UBIFS. Only user-space tools may + * change it. The superblock node mostly contains geometry information. + */ + +#include "ubifs.h" + +/* + * Default journal size in logical eraseblocks as a percent of total + * flash size. + */ +#define DEFAULT_JNL_PERCENT 5 + +/* Default maximum journal size in bytes */ +#define DEFAULT_MAX_JNL (32*1024*1024) + +/* Default indexing tree fanout */ +#define DEFAULT_FANOUT 8 + +/* Default number of data journal heads */ +#define DEFAULT_JHEADS_CNT 1 + +/* Default positions of different LEBs in the main area */ +#define DEFAULT_IDX_LEB 0 +#define DEFAULT_DATA_LEB 1 +#define DEFAULT_GC_LEB 2 + +/* Default number of LEB numbers in LPT's save table */ +#define DEFAULT_LSAVE_CNT 256 + +/* Default reserved pool size as a percent of maximum free space */ +#define DEFAULT_RP_PERCENT 5 + +/* The default maximum size of reserved pool in bytes */ +#define DEFAULT_MAX_RP_SIZE (5*1024*1024) + +/* Default time granularity in nanoseconds */ +#define DEFAULT_TIME_GRAN 1000000000 + +/** + * validate_sb - validate superblock node. + * @c: UBIFS file-system description object + * @sup: superblock node + * + * This function validates superblock node @sup. Since most of data was read + * from the superblock and stored in @c, the function validates fields in @c + * instead. Returns zero in case of success and %-EINVAL in case of validation + * failure. + */ +static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup) +{ + long long max_bytes; + int err = 1, min_leb_cnt; + + if (!c->key_hash) { + err = 2; + goto failed; + } + + if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) { + err = 3; + goto failed; + } + + if (le32_to_cpu(sup->min_io_size) != c->min_io_size) { + ubifs_err("min. I/O unit mismatch: %d in superblock, %d real", + le32_to_cpu(sup->min_io_size), c->min_io_size); + goto failed; + } + + if (le32_to_cpu(sup->leb_size) != c->leb_size) { + ubifs_err("LEB size mismatch: %d in superblock, %d real", + le32_to_cpu(sup->leb_size), c->leb_size); + goto failed; + } + + if (c->log_lebs < UBIFS_MIN_LOG_LEBS || + c->lpt_lebs < UBIFS_MIN_LPT_LEBS || + c->orph_lebs < UBIFS_MIN_ORPH_LEBS || + c->main_lebs < UBIFS_MIN_MAIN_LEBS) { + err = 4; + goto failed; + } + + /* + * Calculate minimum allowed amount of main area LEBs. This is very + * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we + * have just read from the superblock. + */ + min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs; + min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6; + + if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) { + ubifs_err("bad LEB count: %d in superblock, %d on UBI volume, " + "%d minimum required", c->leb_cnt, c->vi.size, + min_leb_cnt); + goto failed; + } + + if (c->max_leb_cnt < c->leb_cnt) { + ubifs_err("max. LEB count %d less than LEB count %d", + c->max_leb_cnt, c->leb_cnt); + goto failed; + } + + if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) { + err = 7; + goto failed; + } + + if (c->max_bud_bytes < (long long)c->leb_size * UBIFS_MIN_BUD_LEBS || + c->max_bud_bytes > (long long)c->leb_size * c->main_lebs) { + err = 8; + goto failed; + } + + if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 || + c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) { + err = 9; + goto failed; + } + + if (c->fanout < UBIFS_MIN_FANOUT || + ubifs_idx_node_sz(c, c->fanout) > c->leb_size) { + err = 10; + goto failed; + } + + if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT && + c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - + c->log_lebs - c->lpt_lebs - c->orph_lebs)) { + err = 11; + goto failed; + } + + if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs + + c->orph_lebs + c->main_lebs != c->leb_cnt) { + err = 12; + goto failed; + } + + if (c->default_compr < 0 || c->default_compr >= UBIFS_COMPR_TYPES_CNT) { + err = 13; + goto failed; + } + + max_bytes = c->main_lebs * (long long)c->leb_size; + if (c->rp_size < 0 || max_bytes < c->rp_size) { + err = 14; + goto failed; + } + + if (le32_to_cpu(sup->time_gran) > 1000000000 || + le32_to_cpu(sup->time_gran) < 1) { + err = 15; + goto failed; + } + + return 0; + +failed: + ubifs_err("bad superblock, error %d", err); + dbg_dump_node(c, sup); + return -EINVAL; +} + +/** + * ubifs_read_sb_node - read superblock node. + * @c: UBIFS file-system description object + * + * This function returns a pointer to the superblock node or a negative error + * code. + */ +struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c) +{ + struct ubifs_sb_node *sup; + int err; + + sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS); + if (!sup) + return ERR_PTR(-ENOMEM); + + err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ, + UBIFS_SB_LNUM, 0); + if (err) { + kfree(sup); + return ERR_PTR(err); + } + + return sup; +} + +/** + * ubifs_read_superblock - read superblock. + * @c: UBIFS file-system description object + * + * This function finds, reads and checks the superblock. If an empty UBI volume + * is being mounted, this function creates default superblock. Returns zero in + * case of success, and a negative error code in case of failure. + */ +int ubifs_read_superblock(struct ubifs_info *c) +{ + int err, sup_flags; + struct ubifs_sb_node *sup; + + if (c->empty) { + printf("No UBIFS filesystem found!\n"); + return -1; + } + + sup = ubifs_read_sb_node(c); + if (IS_ERR(sup)) + return PTR_ERR(sup); + + c->fmt_version = le32_to_cpu(sup->fmt_version); + c->ro_compat_version = le32_to_cpu(sup->ro_compat_version); + + /* + * The software supports all previous versions but not future versions, + * due to the unavailability of time-travelling equipment. + */ + if (c->fmt_version > UBIFS_FORMAT_VERSION) { + struct super_block *sb = c->vfs_sb; + int mounting_ro = sb->s_flags & MS_RDONLY; + + ubifs_assert(!c->ro_media || mounting_ro); + if (!mounting_ro || + c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) { + ubifs_err("on-flash format version is w%d/r%d, but " + "software only supports up to version " + "w%d/r%d", c->fmt_version, + c->ro_compat_version, UBIFS_FORMAT_VERSION, + UBIFS_RO_COMPAT_VERSION); + if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) { + ubifs_msg("only R/O mounting is possible"); + err = -EROFS; + } else + err = -EINVAL; + goto out; + } + + /* + * The FS is mounted R/O, and the media format is + * R/O-compatible with the UBIFS implementation, so we can + * mount. + */ + c->rw_incompat = 1; + } + + if (c->fmt_version < 3) { + ubifs_err("on-flash format version %d is not supported", + c->fmt_version); + err = -EINVAL; + goto out; + } + + switch (sup->key_hash) { + case UBIFS_KEY_HASH_R5: + c->key_hash = key_r5_hash; + c->key_hash_type = UBIFS_KEY_HASH_R5; + break; + + case UBIFS_KEY_HASH_TEST: + c->key_hash = key_test_hash; + c->key_hash_type = UBIFS_KEY_HASH_TEST; + break; + }; + + c->key_fmt = sup->key_fmt; + + switch (c->key_fmt) { + case UBIFS_SIMPLE_KEY_FMT: + c->key_len = UBIFS_SK_LEN; + break; + default: + ubifs_err("unsupported key format"); + err = -EINVAL; + goto out; + } + + c->leb_cnt = le32_to_cpu(sup->leb_cnt); + c->max_leb_cnt = le32_to_cpu(sup->max_leb_cnt); + c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes); + c->log_lebs = le32_to_cpu(sup->log_lebs); + c->lpt_lebs = le32_to_cpu(sup->lpt_lebs); + c->orph_lebs = le32_to_cpu(sup->orph_lebs); + c->jhead_cnt = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT; + c->fanout = le32_to_cpu(sup->fanout); + c->lsave_cnt = le32_to_cpu(sup->lsave_cnt); + c->default_compr = le16_to_cpu(sup->default_compr); + c->rp_size = le64_to_cpu(sup->rp_size); + c->rp_uid = le32_to_cpu(sup->rp_uid); + c->rp_gid = le32_to_cpu(sup->rp_gid); + sup_flags = le32_to_cpu(sup->flags); + + c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran); + memcpy(&c->uuid, &sup->uuid, 16); + c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT); + + /* Automatically increase file system size to the maximum size */ + c->old_leb_cnt = c->leb_cnt; + if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) { + c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size); + dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs", + c->old_leb_cnt, c->leb_cnt); + } + + c->log_bytes = (long long)c->log_lebs * c->leb_size; + c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1; + c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs; + c->lpt_last = c->lpt_first + c->lpt_lebs - 1; + c->orph_first = c->lpt_last + 1; + c->orph_last = c->orph_first + c->orph_lebs - 1; + c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS; + c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs; + c->main_first = c->leb_cnt - c->main_lebs; + c->report_rp_size = ubifs_reported_space(c, c->rp_size); + + err = validate_sb(c, sup); +out: + kfree(sup); + return err; +} -- 1.7.1