diff options
Diffstat (limited to 'fs/ubifs/log.c')
| -rw-r--r-- | fs/ubifs/log.c | 805 |
1 files changed, 805 insertions, 0 deletions
diff --git a/fs/ubifs/log.c b/fs/ubifs/log.c new file mode 100644 index 0000000..36857b9 --- /dev/null +++ b/fs/ubifs/log.c @@ -0,0 +1,805 @@ +/* + * 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 (Битюцкий Артём) + * Adrian Hunter + */ + +/* + * This file is a part of UBIFS journal implementation and contains various + * functions which manipulate the log. The log is a fixed area on the flash + * which does not contain any data but refers to buds. The log is a part of the + * journal. + */ + +#include "ubifs.h" + +#ifdef CONFIG_UBIFS_FS_DEBUG +static int dbg_check_bud_bytes(struct ubifs_info *c); +#else +#define dbg_check_bud_bytes(c) 0 +#endif + +/** + * ubifs_search_bud - search bud LEB. + * @c: UBIFS file-system description object + * @lnum: logical eraseblock number to search + * + * This function searches bud LEB @lnum. Returns bud description object in case + * of success and %NULL if there is no bud with this LEB number. + */ +struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum) +{ + struct rb_node *p; + struct ubifs_bud *bud; + + spin_lock(&c->buds_lock); + p = c->buds.rb_node; + while (p) { + bud = rb_entry(p, struct ubifs_bud, rb); + if (lnum < bud->lnum) + p = p->rb_left; + else if (lnum > bud->lnum) + p = p->rb_right; + else { + spin_unlock(&c->buds_lock); + return bud; + } + } + spin_unlock(&c->buds_lock); + return NULL; +} + +/** + * ubifs_get_wbuf - get the wbuf associated with a LEB, if there is one. + * @c: UBIFS file-system description object + * @lnum: logical eraseblock number to search + * + * This functions returns the wbuf for @lnum or %NULL if there is not one. + */ +struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum) +{ + struct rb_node *p; + struct ubifs_bud *bud; + int jhead; + + if (!c->jheads) + return NULL; + + spin_lock(&c->buds_lock); + p = c->buds.rb_node; + while (p) { + bud = rb_entry(p, struct ubifs_bud, rb); + if (lnum < bud->lnum) + p = p->rb_left; + else if (lnum > bud->lnum) + p = p->rb_right; + else { + jhead = bud->jhead; + spin_unlock(&c->buds_lock); + return &c->jheads[jhead].wbuf; + } + } + spin_unlock(&c->buds_lock); + return NULL; +} + +/** + * next_log_lnum - switch to the next log LEB. + * @c: UBIFS file-system description object + * @lnum: current log LEB + */ +static inline int next_log_lnum(const struct ubifs_info *c, int lnum) +{ + lnum += 1; + if (lnum > c->log_last) + lnum = UBIFS_LOG_LNUM; + + return lnum; +} + +/** + * empty_log_bytes - calculate amount of empty space in the log. + * @c: UBIFS file-system description object + */ +static inline long long empty_log_bytes(const struct ubifs_info *c) +{ + long long h, t; + + h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs; + t = (long long)c->ltail_lnum * c->leb_size; + + if (h >= t) + return c->log_bytes - h + t; + else + return t - h; +} + +/** + * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list. + * @c: UBIFS file-system description object + * @bud: the bud to add + */ +void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud) +{ + struct rb_node **p, *parent = NULL; + struct ubifs_bud *b; + struct ubifs_jhead *jhead; + + spin_lock(&c->buds_lock); + p = &c->buds.rb_node; + while (*p) { + parent = *p; + b = rb_entry(parent, struct ubifs_bud, rb); + ubifs_assert(bud->lnum != b->lnum); + if (bud->lnum < b->lnum) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + + rb_link_node(&bud->rb, parent, p); + rb_insert_color(&bud->rb, &c->buds); + if (c->jheads) { + jhead = &c->jheads[bud->jhead]; + list_add_tail(&bud->list, &jhead->buds_list); + } else + ubifs_assert(c->replaying && (c->vfs_sb->s_flags & MS_RDONLY)); + + /* + * Note, although this is a new bud, we anyway account this space now, + * before any data has been written to it, because this is about to + * guarantee fixed mount time, and this bud will anyway be read and + * scanned. + */ + c->bud_bytes += c->leb_size - bud->start; + + dbg_log("LEB %d:%d, jhead %d, bud_bytes %lld", bud->lnum, + bud->start, bud->jhead, c->bud_bytes); + spin_unlock(&c->buds_lock); +} + +/** + * ubifs_create_buds_lists - create journal head buds lists for remount rw. + * @c: UBIFS file-system description object + */ +void ubifs_create_buds_lists(struct ubifs_info *c) +{ + struct rb_node *p; + + spin_lock(&c->buds_lock); + p = rb_first(&c->buds); + while (p) { + struct ubifs_bud *bud = rb_entry(p, struct ubifs_bud, rb); + struct ubifs_jhead *jhead = &c->jheads[bud->jhead]; + + list_add_tail(&bud->list, &jhead->buds_list); + p = rb_next(p); + } + spin_unlock(&c->buds_lock); +} + +/** + * ubifs_add_bud_to_log - add a new bud to the log. + * @c: UBIFS file-system description object + * @jhead: journal head the bud belongs to + * @lnum: LEB number of the bud + * @offs: starting offset of the bud + * + * This function writes reference node for the new bud LEB @lnum it to the log, + * and adds it to the buds tress. It also makes sure that log size does not + * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success, + * %-EAGAIN if commit is required, and a negative error codes in case of + * failure. + */ +int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs) +{ + int err; + struct ubifs_bud *bud; + struct ubifs_ref_node *ref; + + bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS); + if (!bud) + return -ENOMEM; + ref = kzalloc(c->ref_node_alsz, GFP_NOFS); + if (!ref) { + kfree(bud); + return -ENOMEM; + } + + mutex_lock(&c->log_mutex); + + if (c->ro_media) { + err = -EROFS; + goto out_unlock; + } + + /* Make sure we have enough space in the log */ + if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) { + dbg_log("not enough log space - %lld, required %d", + empty_log_bytes(c), c->min_log_bytes); + ubifs_commit_required(c); + err = -EAGAIN; + goto out_unlock; + } + + /* + * Make sure the the amount of space in buds will not exceed + * 'c->max_bud_bytes' limit, because we want to guarantee mount time + * limits. + * + * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes + * because we are holding @c->log_mutex. All @c->bud_bytes take place + * when both @c->log_mutex and @c->bud_bytes are locked. + */ + if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) { + dbg_log("bud bytes %lld (%lld max), require commit", + c->bud_bytes, c->max_bud_bytes); + ubifs_commit_required(c); + err = -EAGAIN; + goto out_unlock; + } + + /* + * If the journal is full enough - start background commit. Note, it is + * OK to read 'c->cmt_state' without spinlock because integer reads + * are atomic in the kernel. + */ + if (c->bud_bytes >= c->bg_bud_bytes && + c->cmt_state == COMMIT_RESTING) { + dbg_log("bud bytes %lld (%lld max), initiate BG commit", + c->bud_bytes, c->max_bud_bytes); + ubifs_request_bg_commit(c); + } + + bud->lnum = lnum; + bud->start = offs; + bud->jhead = jhead; + + ref->ch.node_type = UBIFS_REF_NODE; + ref->lnum = cpu_to_le32(bud->lnum); + ref->offs = cpu_to_le32(bud->start); + ref->jhead = cpu_to_le32(jhead); + + if (c->lhead_offs > c->leb_size - c->ref_node_alsz) { + c->lhead_lnum = next_log_lnum(c, c->lhead_lnum); + c->lhead_offs = 0; + } + + if (c->lhead_offs == 0) { + /* Must ensure next log LEB has been unmapped */ + err = ubifs_leb_unmap(c, c->lhead_lnum); + if (err) + goto out_unlock; + } + + if (bud->start == 0) { + /* + * Before writing the LEB reference which refers an empty LEB + * to the log, we have to make sure it is mapped, because + * otherwise we'd risk to refer an LEB with garbage in case of + * an unclean reboot, because the target LEB might have been + * unmapped, but not yet physically erased. + */ + err = ubi_leb_map(c->ubi, bud->lnum, UBI_SHORTTERM); + if (err) + goto out_unlock; + } + + dbg_log("write ref LEB %d:%d", + c->lhead_lnum, c->lhead_offs); + err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum, + c->lhead_offs, UBI_SHORTTERM); + if (err) + goto out_unlock; + + c->lhead_offs += c->ref_node_alsz; + + ubifs_add_bud(c, bud); + + mutex_unlock(&c->log_mutex); + kfree(ref); + return 0; + +out_unlock: + mutex_unlock(&c->log_mutex); + kfree(ref); + kfree(bud); + return err; +} + +/** + * remove_buds - remove used buds. + * @c: UBIFS file-system description object + * + * This function removes use buds from the buds tree. It does not remove the + * buds which are pointed to by journal heads. + */ +static void remove_buds(struct ubifs_info *c) +{ + struct rb_node *p; + + ubifs_assert(list_empty(&c->old_buds)); + c->cmt_bud_bytes = 0; + spin_lock(&c->buds_lock); + p = rb_first(&c->buds); + while (p) { + struct rb_node *p1 = p; + struct ubifs_bud *bud; + struct ubifs_wbuf *wbuf; + + p = rb_next(p); + bud = rb_entry(p1, struct ubifs_bud, rb); + wbuf = &c->jheads[bud->jhead].wbuf; + + if (wbuf->lnum == bud->lnum) { + /* + * Do not remove buds which are pointed to by journal + * heads (non-closed buds). + */ + c->cmt_bud_bytes += wbuf->offs - bud->start; + dbg_log("preserve %d:%d, jhead %d, bud bytes %d, " + "cmt_bud_bytes %lld", bud->lnum, bud->start, + bud->jhead, wbuf->offs - bud->start, + c->cmt_bud_bytes); + bud->start = wbuf->offs; + } else { + c->cmt_bud_bytes += c->leb_size - bud->start; + dbg_log("remove %d:%d, jhead %d, bud bytes %d, " + "cmt_bud_bytes %lld", bud->lnum, bud->start, + bud->jhead, c->leb_size - bud->start, + c->cmt_bud_bytes); + rb_erase(p1, &c->buds); + list_del(&bud->list); + /* + * If the commit does not finish, the recovery will need + * to replay the journal, in which case the old buds + * must be unchanged. Do not release them until post + * commit i.e. do not allow them to be garbage + * collected. + */ + list_add(&bud->list, &c->old_buds); + } + } + spin_unlock(&c->buds_lock); +} + +/** + * ubifs_log_start_commit - start commit. + * @c: UBIFS file-system description object + * @ltail_lnum: return new log tail LEB number + * + * The commit operation starts with writing "commit start" node to the log and + * reference nodes for all journal heads which will define new journal after + * the commit has been finished. The commit start and reference nodes are + * written in one go to the nearest empty log LEB (hence, when commit is + * finished UBIFS may safely unmap all the previous log LEBs). This function + * returns zero in case of success and a negative error code in case of + * failure. + */ +int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum) +{ + void *buf; + struct ubifs_cs_node *cs; + struct ubifs_ref_node *ref; + int err, i, max_len, len; + + err = dbg_check_bud_bytes(c); + if (err) + return err; + + max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ; + max_len = ALIGN(max_len, c->min_io_size); + buf = cs = kmalloc(max_len, GFP_NOFS); + if (!buf) + return -ENOMEM; + + cs->ch.node_type = UBIFS_CS_NODE; + cs->cmt_no = cpu_to_le64(c->cmt_no + 1); + ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0); + + /* + * Note, we do not lock 'c->log_mutex' because this is the commit start + * phase and we are exclusively using the log. And we do not lock + * write-buffer because nobody can write to the file-system at this + * phase. + */ + + len = UBIFS_CS_NODE_SZ; + for (i = 0; i < c->jhead_cnt; i++) { + int lnum = c->jheads[i].wbuf.lnum; + int offs = c->jheads[i].wbuf.offs; + + if (lnum == -1 || offs == c->leb_size) + continue; + + dbg_log("add ref to LEB %d:%d for jhead %d", lnum, offs, i); + ref = buf + len; + ref->ch.node_type = UBIFS_REF_NODE; + ref->lnum = cpu_to_le32(lnum); + ref->offs = cpu_to_le32(offs); + ref->jhead = cpu_to_le32(i); + + ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0); + len += UBIFS_REF_NODE_SZ; + } + + ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len); + + /* Switch to the next log LEB */ + if (c->lhead_offs) { + c->lhead_lnum = next_log_lnum(c, c->lhead_lnum); + c->lhead_offs = 0; + } + + if (c->lhead_offs == 0) { + /* Must ensure next LEB has been unmapped */ + err = ubifs_leb_unmap(c, c->lhead_lnum); + if (err) + goto out; + } + + len = ALIGN(len, c->min_io_size); + dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len); + err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len, UBI_SHORTTERM); + if (err) + goto out; + + *ltail_lnum = c->lhead_lnum; + + c->lhead_offs += len; + if (c->lhead_offs == c->leb_size) { + c->lhead_lnum = next_log_lnum(c, c->lhead_lnum); + c->lhead_offs = 0; + } + + remove_buds(c); + + /* + * We have started the commit and now users may use the rest of the log + * for new writes. + */ + c->min_log_bytes = 0; + +out: + kfree(buf); + return err; +} + +/** + * ubifs_log_end_commit - end commit. + * @c: UBIFS file-system description object + * @ltail_lnum: new log tail LEB number + * + * This function is called on when the commit operation was finished. It + * moves log tail to new position and unmaps LEBs which contain obsolete data. + * Returns zero in case of success and a negative error code in case of + * failure. + */ +int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum) +{ + int err; + + /* + * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS + * writes during commit. Its only short "commit" start phase when + * writers are blocked. + */ + mutex_lock(&c->log_mutex); + + dbg_log("old tail was LEB %d:0, new tail is LEB %d:0", + c->ltail_lnum, ltail_lnum); + + c->ltail_lnum = ltail_lnum; + /* + * The commit is finished and from now on it must be guaranteed that + * there is always enough space for the next commit. + */ + c->min_log_bytes = c->leb_size; + + spin_lock(&c->buds_lock); + c->bud_bytes -= c->cmt_bud_bytes; + spin_unlock(&c->buds_lock); + + err = dbg_check_bud_bytes(c); + + mutex_unlock(&c->log_mutex); + return err; +} + +/** + * ubifs_log_post_commit - things to do after commit is completed. + * @c: UBIFS file-system description object + * @old_ltail_lnum: old log tail LEB number + * + * Release buds only after commit is completed, because they must be unchanged + * if recovery is needed. + * + * Unmap log LEBs only after commit is completed, because they may be needed for + * recovery. + * + * This function returns %0 on success and a negative error code on failure. + */ +int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum) +{ + int lnum, err = 0; + + while (!list_empty(&c->old_buds)) { + struct ubifs_bud *bud; + + bud = list_entry(c->old_buds.next, struct ubifs_bud, list); + err = ubifs_return_leb(c, bud->lnum); + if (err) + return err; + list_del(&bud->list); + kfree(bud); + } + mutex_lock(&c->log_mutex); + for (lnum = old_ltail_lnum; lnum != c->ltail_lnum; + lnum = next_log_lnum(c, lnum)) { + dbg_log("unmap log LEB %d", lnum); + err = ubifs_leb_unmap(c, lnum); + if (err) + goto out; + } +out: + mutex_unlock(&c->log_mutex); + return err; +} + +/** + * struct done_ref - references that have been done. + * @rb: rb-tree node + * @lnum: LEB number + */ +struct done_ref { + struct rb_node rb; + int lnum; +}; + +/** + * done_already - determine if a reference has been done already. + * @done_tree: rb-tree to store references that have been done + * @lnum: LEB number of reference + * + * This function returns %1 if the reference has been done, %0 if not, otherwise + * a negative error code is returned. + */ +static int done_already(struct rb_root *done_tree, int lnum) +{ + struct rb_node **p = &done_tree->rb_node, *parent = NULL; + struct done_ref *dr; + + while (*p) { + parent = *p; + dr = rb_entry(parent, struct done_ref, rb); + if (lnum < dr->lnum) + p = &(*p)->rb_left; + else if (lnum > dr->lnum) + p = &(*p)->rb_right; + else + return 1; + } + + dr = kzalloc(sizeof(struct done_ref), GFP_NOFS); + if (!dr) + return -ENOMEM; + + dr->lnum = lnum; + + rb_link_node(&dr->rb, parent, p); + rb_insert_color(&dr->rb, done_tree); + + return 0; +} + +/** + * destroy_done_tree - destroy the done tree. + * @done_tree: done tree to destroy + */ +static void destroy_done_tree(struct rb_root *done_tree) +{ + struct rb_node *this = done_tree->rb_node; + struct done_ref *dr; + + while (this) { + if (this->rb_left) { + this = this->rb_left; + continue; + } else if (this->rb_right) { + this = this->rb_right; + continue; + } + dr = rb_entry(this, struct done_ref, rb); + this = rb_parent(this); + if (this) { + if (this->rb_left == &dr->rb) + this->rb_left = NULL; + else + this->rb_right = NULL; + } + kfree(dr); + } +} + +/** + * add_node - add a node to the consolidated log. + * @c: UBIFS file-system description object + * @buf: buffer to which to add + * @lnum: LEB number to which to write is passed and returned here + * @offs: offset to where to write is passed and returned here + * @node: node to add + * + * This function returns %0 on success and a negative error code on failure. + */ +static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs, + void *node) +{ + struct ubifs_ch *ch = node; + int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs; + + if (len > remains) { + int sz = ALIGN(*offs, c->min_io_size), err; + + ubifs_pad(c, buf + *offs, sz - *offs); + err = ubifs_leb_change(c, *lnum, buf, sz, UBI_SHORTTERM); + if (err) + return err; + *lnum = next_log_lnum(c, *lnum); + *offs = 0; + } + memcpy(buf + *offs, node, len); + *offs += ALIGN(len, 8); + return 0; +} + +/** + * ubifs_consolidate_log - consolidate the log. + * @c: UBIFS file-system description object + * + * Repeated failed commits could cause the log to be full, but at least 1 LEB is + * needed for commit. This function rewrites the reference nodes in the log + * omitting duplicates, and failed CS nodes, and leaving no gaps. + * + * This function returns %0 on success and a negative error code on failure. + */ +int ubifs_consolidate_log(struct ubifs_info *c) +{ + struct ubifs_scan_leb *sleb; + struct ubifs_scan_node *snod; + struct rb_root done_tree = RB_ROOT; + int lnum, err, first = 1, write_lnum, offs = 0; + void *buf; + + dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum, + c->lhead_lnum); + buf = vmalloc(c->leb_size); + if (!buf) + return -ENOMEM; + lnum = c->ltail_lnum; + write_lnum = lnum; + while (1) { + sleb = ubifs_scan(c, lnum, 0, c->sbuf); + if (IS_ERR(sleb)) { + err = PTR_ERR(sleb); + goto out_free; + } + list_for_each_entry(snod, &sleb->nodes, list) { + switch (snod->type) { + case UBIFS_REF_NODE: { + struct ubifs_ref_node *ref = snod->node; + int ref_lnum = le32_to_cpu(ref->lnum); + + err = done_already(&done_tree, ref_lnum); + if (err < 0) + goto out_scan; + if (err != 1) { + err = add_node(c, buf, &write_lnum, + &offs, snod->node); + if (err) + goto out_scan; + } + break; + } + case UBIFS_CS_NODE: + if (!first) + break; + err = add_node(c, buf, &write_lnum, &offs, + snod->node); + if (err) + goto out_scan; + first = 0; + break; + } + } + ubifs_scan_destroy(sleb); + if (lnum == c->lhead_lnum) + break; + lnum = next_log_lnum(c, lnum); + } + if (offs) { + int sz = ALIGN(offs, c->min_io_size); + + ubifs_pad(c, buf + offs, sz - offs); + err = ubifs_leb_change(c, write_lnum, buf, sz, UBI_SHORTTERM); + if (err) + goto out_free; + offs = ALIGN(offs, c->min_io_size); + } + destroy_done_tree(&done_tree); + vfree(buf); + if (write_lnum == c->lhead_lnum) { + ubifs_err("log is too full"); + return -EINVAL; + } + /* Unmap remaining LEBs */ + lnum = write_lnum; + do { + lnum = next_log_lnum(c, lnum); + err = ubifs_leb_unmap(c, lnum); + if (err) + return err; + } while (lnum != c->lhead_lnum); + c->lhead_lnum = write_lnum; + c->lhead_offs = offs; + dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs); + return 0; + +out_scan: + ubifs_scan_destroy(sleb); +out_free: + destroy_done_tree(&done_tree); + vfree(buf); + return err; +} + +#ifdef CONFIG_UBIFS_FS_DEBUG + +/** + * dbg_check_bud_bytes - make sure bud bytes calculation are all right. + * @c: UBIFS file-system description object + * + * This function makes sure the amount of flash space used by closed buds + * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in + * case of failure. + */ +static int dbg_check_bud_bytes(struct ubifs_info *c) +{ + int i, err = 0; + struct ubifs_bud *bud; + long long bud_bytes = 0; + + if (!(ubifs_chk_flags & UBIFS_CHK_GEN)) + return 0; + + spin_lock(&c->buds_lock); + for (i = 0; i < c->jhead_cnt; i++) + list_for_each_entry(bud, &c->jheads[i].buds_list, list) + bud_bytes += c->leb_size - bud->start; + + if (c->bud_bytes != bud_bytes) { + ubifs_err("bad bud_bytes %lld, calculated %lld", + c->bud_bytes, bud_bytes); + err = -EINVAL; + } + spin_unlock(&c->buds_lock); + + return err; +} + +#endif /* CONFIG_UBIFS_FS_DEBUG */ |
