diff options
Diffstat (limited to 'fs/ubifs/commit.c')
| -rw-r--r-- | fs/ubifs/commit.c | 722 |
1 files changed, 722 insertions, 0 deletions
diff --git a/fs/ubifs/commit.c b/fs/ubifs/commit.c new file mode 100644 index 000000000..b5cdac9b0 --- /dev/null +++ b/fs/ubifs/commit.c @@ -0,0 +1,722 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This file is part of UBIFS. + * + * Copyright (C) 2006-2008 Nokia Corporation. + * + * Authors: Adrian Hunter + * Artem Bityutskiy (Битюцкий Артём) + */ + +/* + * This file implements functions that manage the running of the commit process. + * Each affected module has its own functions to accomplish their part in the + * commit and those functions are called here. + * + * The commit is the process whereby all updates to the index and LEB properties + * are written out together and the journal becomes empty. This keeps the + * file system consistent - at all times the state can be recreated by reading + * the index and LEB properties and then replaying the journal. + * + * The commit is split into two parts named "commit start" and "commit end". + * During commit start, the commit process has exclusive access to the journal + * by holding the commit semaphore down for writing. As few I/O operations as + * possible are performed during commit start, instead the nodes that are to be + * written are merely identified. During commit end, the commit semaphore is no + * longer held and the journal is again in operation, allowing users to continue + * to use the file system while the bulk of the commit I/O is performed. The + * purpose of this two-step approach is to prevent the commit from causing any + * latency blips. Note that in any case, the commit does not prevent lookups + * (as permitted by the TNC mutex), or access to VFS data structures e.g. page + * cache. + */ + +#include <linux/freezer.h> +#include <linux/kthread.h> +#include <linux/slab.h> +#include "ubifs.h" + +/* + * nothing_to_commit - check if there is nothing to commit. + * @c: UBIFS file-system description object + * + * This is a helper function which checks if there is anything to commit. It is + * used as an optimization to avoid starting the commit if it is not really + * necessary. Indeed, the commit operation always assumes flash I/O (e.g., + * writing the commit start node to the log), and it is better to avoid doing + * this unnecessarily. E.g., 'ubifs_sync_fs()' runs the commit, but if there is + * nothing to commit, it is more optimal to avoid any flash I/O. + * + * This function has to be called with @c->commit_sem locked for writing - + * this function does not take LPT/TNC locks because the @c->commit_sem + * guarantees that we have exclusive access to the TNC and LPT data structures. + * + * This function returns %1 if there is nothing to commit and %0 otherwise. + */ +static int nothing_to_commit(struct ubifs_info *c) +{ + /* + * During mounting or remounting from R/O mode to R/W mode we may + * commit for various recovery-related reasons. + */ + if (c->mounting || c->remounting_rw) + return 0; + + /* + * If the root TNC node is dirty, we definitely have something to + * commit. + */ + if (c->zroot.znode && ubifs_zn_dirty(c->zroot.znode)) + return 0; + + /* + * Even though the TNC is clean, the LPT tree may have dirty nodes. For + * example, this may happen if the budgeting subsystem invoked GC to + * make some free space, and the GC found an LEB with only dirty and + * free space. In this case GC would just change the lprops of this + * LEB (by turning all space into free space) and unmap it. + */ + if (c->nroot && test_bit(DIRTY_CNODE, &c->nroot->flags)) + return 0; + + ubifs_assert(c, atomic_long_read(&c->dirty_zn_cnt) == 0); + ubifs_assert(c, c->dirty_pn_cnt == 0); + ubifs_assert(c, c->dirty_nn_cnt == 0); + + return 1; +} + +/** + * do_commit - commit the journal. + * @c: UBIFS file-system description object + * + * This function implements UBIFS commit. It has to be called with commit lock + * locked. Returns zero in case of success and a negative error code in case of + * failure. + */ +static int do_commit(struct ubifs_info *c) +{ + int err, new_ltail_lnum, old_ltail_lnum, i; + struct ubifs_zbranch zroot; + struct ubifs_lp_stats lst; + + dbg_cmt("start"); + ubifs_assert(c, !c->ro_media && !c->ro_mount); + + if (c->ro_error) { + err = -EROFS; + goto out_up; + } + + if (nothing_to_commit(c)) { + up_write(&c->commit_sem); + err = 0; + goto out_cancel; + } + + /* Sync all write buffers (necessary for recovery) */ + for (i = 0; i < c->jhead_cnt; i++) { + err = ubifs_wbuf_sync(&c->jheads[i].wbuf); + if (err) + goto out_up; + } + + c->cmt_no += 1; + err = ubifs_gc_start_commit(c); + if (err) + goto out_up; + err = dbg_check_lprops(c); + if (err) + goto out_up; + err = ubifs_log_start_commit(c, &new_ltail_lnum); + if (err) + goto out_up; + err = ubifs_tnc_start_commit(c, &zroot); + if (err) + goto out_up; + err = ubifs_lpt_start_commit(c); + if (err) + goto out_up; + err = ubifs_orphan_start_commit(c); + if (err) + goto out_up; + + ubifs_get_lp_stats(c, &lst); + + up_write(&c->commit_sem); + + err = ubifs_tnc_end_commit(c); + if (err) + goto out; + err = ubifs_lpt_end_commit(c); + if (err) + goto out; + err = ubifs_orphan_end_commit(c); + if (err) + goto out; + err = dbg_check_old_index(c, &zroot); + if (err) + goto out; + + c->mst_node->cmt_no = cpu_to_le64(c->cmt_no); + c->mst_node->log_lnum = cpu_to_le32(new_ltail_lnum); + c->mst_node->root_lnum = cpu_to_le32(zroot.lnum); + c->mst_node->root_offs = cpu_to_le32(zroot.offs); + c->mst_node->root_len = cpu_to_le32(zroot.len); + c->mst_node->ihead_lnum = cpu_to_le32(c->ihead_lnum); + c->mst_node->ihead_offs = cpu_to_le32(c->ihead_offs); + c->mst_node->index_size = cpu_to_le64(c->bi.old_idx_sz); + c->mst_node->lpt_lnum = cpu_to_le32(c->lpt_lnum); + c->mst_node->lpt_offs = cpu_to_le32(c->lpt_offs); + c->mst_node->nhead_lnum = cpu_to_le32(c->nhead_lnum); + c->mst_node->nhead_offs = cpu_to_le32(c->nhead_offs); + c->mst_node->ltab_lnum = cpu_to_le32(c->ltab_lnum); + c->mst_node->ltab_offs = cpu_to_le32(c->ltab_offs); + c->mst_node->lsave_lnum = cpu_to_le32(c->lsave_lnum); + c->mst_node->lsave_offs = cpu_to_le32(c->lsave_offs); + c->mst_node->lscan_lnum = cpu_to_le32(c->lscan_lnum); + c->mst_node->empty_lebs = cpu_to_le32(lst.empty_lebs); + c->mst_node->idx_lebs = cpu_to_le32(lst.idx_lebs); + c->mst_node->total_free = cpu_to_le64(lst.total_free); + c->mst_node->total_dirty = cpu_to_le64(lst.total_dirty); + c->mst_node->total_used = cpu_to_le64(lst.total_used); + c->mst_node->total_dead = cpu_to_le64(lst.total_dead); + c->mst_node->total_dark = cpu_to_le64(lst.total_dark); + if (c->no_orphs) + c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS); + else + c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_NO_ORPHS); + + old_ltail_lnum = c->ltail_lnum; + err = ubifs_log_end_commit(c, new_ltail_lnum); + if (err) + goto out; + + err = ubifs_log_post_commit(c, old_ltail_lnum); + if (err) + goto out; + err = ubifs_gc_end_commit(c); + if (err) + goto out; + err = ubifs_lpt_post_commit(c); + if (err) + goto out; + +out_cancel: + spin_lock(&c->cs_lock); + c->cmt_state = COMMIT_RESTING; + wake_up(&c->cmt_wq); + dbg_cmt("commit end"); + spin_unlock(&c->cs_lock); + return 0; + +out_up: + up_write(&c->commit_sem); +out: + ubifs_err(c, "commit failed, error %d", err); + spin_lock(&c->cs_lock); + c->cmt_state = COMMIT_BROKEN; + wake_up(&c->cmt_wq); + spin_unlock(&c->cs_lock); + ubifs_ro_mode(c, err); + return err; +} + +/** + * run_bg_commit - run background commit if it is needed. + * @c: UBIFS file-system description object + * + * This function runs background commit if it is needed. Returns zero in case + * of success and a negative error code in case of failure. + */ +static int run_bg_commit(struct ubifs_info *c) +{ + spin_lock(&c->cs_lock); + /* + * Run background commit only if background commit was requested or if + * commit is required. + */ + if (c->cmt_state != COMMIT_BACKGROUND && + c->cmt_state != COMMIT_REQUIRED) + goto out; + spin_unlock(&c->cs_lock); + + down_write(&c->commit_sem); + spin_lock(&c->cs_lock); + if (c->cmt_state == COMMIT_REQUIRED) + c->cmt_state = COMMIT_RUNNING_REQUIRED; + else if (c->cmt_state == COMMIT_BACKGROUND) + c->cmt_state = COMMIT_RUNNING_BACKGROUND; + else + goto out_cmt_unlock; + spin_unlock(&c->cs_lock); + + return do_commit(c); + +out_cmt_unlock: + up_write(&c->commit_sem); +out: + spin_unlock(&c->cs_lock); + return 0; +} + +/** + * ubifs_bg_thread - UBIFS background thread function. + * @info: points to the file-system description object + * + * This function implements various file-system background activities: + * o when a write-buffer timer expires it synchronizes the appropriate + * write-buffer; + * o when the journal is about to be full, it starts in-advance commit. + * + * Note, other stuff like background garbage collection may be added here in + * future. + */ +int ubifs_bg_thread(void *info) +{ + int err; + struct ubifs_info *c = info; + + ubifs_msg(c, "background thread \"%s\" started, PID %d", + c->bgt_name, current->pid); + set_freezable(); + + while (1) { + if (kthread_should_stop()) + break; + + if (try_to_freeze()) + continue; + + set_current_state(TASK_INTERRUPTIBLE); + /* Check if there is something to do */ + if (!c->need_bgt) { + /* + * Nothing prevents us from going sleep now and + * be never woken up and block the task which + * could wait in 'kthread_stop()' forever. + */ + if (kthread_should_stop()) + break; + schedule(); + continue; + } else + __set_current_state(TASK_RUNNING); + + c->need_bgt = 0; + err = ubifs_bg_wbufs_sync(c); + if (err) + ubifs_ro_mode(c, err); + + run_bg_commit(c); + cond_resched(); + } + + ubifs_msg(c, "background thread \"%s\" stops", c->bgt_name); + return 0; +} + +/** + * ubifs_commit_required - set commit state to "required". + * @c: UBIFS file-system description object + * + * This function is called if a commit is required but cannot be done from the + * calling function, so it is just flagged instead. + */ +void ubifs_commit_required(struct ubifs_info *c) +{ + spin_lock(&c->cs_lock); + switch (c->cmt_state) { + case COMMIT_RESTING: + case COMMIT_BACKGROUND: + dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state), + dbg_cstate(COMMIT_REQUIRED)); + c->cmt_state = COMMIT_REQUIRED; + break; + case COMMIT_RUNNING_BACKGROUND: + dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state), + dbg_cstate(COMMIT_RUNNING_REQUIRED)); + c->cmt_state = COMMIT_RUNNING_REQUIRED; + break; + case COMMIT_REQUIRED: + case COMMIT_RUNNING_REQUIRED: + case COMMIT_BROKEN: + break; + } + spin_unlock(&c->cs_lock); +} + +/** + * ubifs_request_bg_commit - notify the background thread to do a commit. + * @c: UBIFS file-system description object + * + * This function is called if the journal is full enough to make a commit + * worthwhile, so background thread is kicked to start it. + */ +void ubifs_request_bg_commit(struct ubifs_info *c) +{ + spin_lock(&c->cs_lock); + if (c->cmt_state == COMMIT_RESTING) { + dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state), + dbg_cstate(COMMIT_BACKGROUND)); + c->cmt_state = COMMIT_BACKGROUND; + spin_unlock(&c->cs_lock); + ubifs_wake_up_bgt(c); + } else + spin_unlock(&c->cs_lock); +} + +/** + * wait_for_commit - wait for commit. + * @c: UBIFS file-system description object + * + * This function sleeps until the commit operation is no longer running. + */ +static int wait_for_commit(struct ubifs_info *c) +{ + dbg_cmt("pid %d goes sleep", current->pid); + + /* + * The following sleeps if the condition is false, and will be woken + * when the commit ends. It is possible, although very unlikely, that we + * will wake up and see the subsequent commit running, rather than the + * one we were waiting for, and go back to sleep. However, we will be + * woken again, so there is no danger of sleeping forever. + */ + wait_event(c->cmt_wq, c->cmt_state != COMMIT_RUNNING_BACKGROUND && + c->cmt_state != COMMIT_RUNNING_REQUIRED); + dbg_cmt("commit finished, pid %d woke up", current->pid); + return 0; +} + +/** + * ubifs_run_commit - run or wait for commit. + * @c: UBIFS file-system description object + * + * This function runs commit and returns zero in case of success and a negative + * error code in case of failure. + */ +int ubifs_run_commit(struct ubifs_info *c) +{ + int err = 0; + + spin_lock(&c->cs_lock); + if (c->cmt_state == COMMIT_BROKEN) { + err = -EROFS; + goto out; + } + + if (c->cmt_state == COMMIT_RUNNING_BACKGROUND) + /* + * We set the commit state to 'running required' to indicate + * that we want it to complete as quickly as possible. + */ + c->cmt_state = COMMIT_RUNNING_REQUIRED; + + if (c->cmt_state == COMMIT_RUNNING_REQUIRED) { + spin_unlock(&c->cs_lock); + return wait_for_commit(c); + } + spin_unlock(&c->cs_lock); + + /* Ok, the commit is indeed needed */ + + down_write(&c->commit_sem); + spin_lock(&c->cs_lock); + /* + * Since we unlocked 'c->cs_lock', the state may have changed, so + * re-check it. + */ + if (c->cmt_state == COMMIT_BROKEN) { + err = -EROFS; + goto out_cmt_unlock; + } + + if (c->cmt_state == COMMIT_RUNNING_BACKGROUND) + c->cmt_state = COMMIT_RUNNING_REQUIRED; + + if (c->cmt_state == COMMIT_RUNNING_REQUIRED) { + up_write(&c->commit_sem); + spin_unlock(&c->cs_lock); + return wait_for_commit(c); + } + c->cmt_state = COMMIT_RUNNING_REQUIRED; + spin_unlock(&c->cs_lock); + + err = do_commit(c); + return err; + +out_cmt_unlock: + up_write(&c->commit_sem); +out: + spin_unlock(&c->cs_lock); + return err; +} + +/** + * ubifs_gc_should_commit - determine if it is time for GC to run commit. + * @c: UBIFS file-system description object + * + * This function is called by garbage collection to determine if commit should + * be run. If commit state is @COMMIT_BACKGROUND, which means that the journal + * is full enough to start commit, this function returns true. It is not + * absolutely necessary to commit yet, but it feels like this should be better + * then to keep doing GC. This function returns %1 if GC has to initiate commit + * and %0 if not. + */ +int ubifs_gc_should_commit(struct ubifs_info *c) +{ + int ret = 0; + + spin_lock(&c->cs_lock); + if (c->cmt_state == COMMIT_BACKGROUND) { + dbg_cmt("commit required now"); + c->cmt_state = COMMIT_REQUIRED; + } else + dbg_cmt("commit not requested"); + if (c->cmt_state == COMMIT_REQUIRED) + ret = 1; + spin_unlock(&c->cs_lock); + return ret; +} + +/* + * Everything below is related to debugging. + */ + +/** + * struct idx_node - hold index nodes during index tree traversal. + * @list: list + * @iip: index in parent (slot number of this indexing node in the parent + * indexing node) + * @upper_key: all keys in this indexing node have to be less or equivalent to + * this key + * @idx: index node (8-byte aligned because all node structures must be 8-byte + * aligned) + */ +struct idx_node { + struct list_head list; + int iip; + union ubifs_key upper_key; + struct ubifs_idx_node idx __aligned(8); +}; + +/** + * dbg_old_index_check_init - get information for the next old index check. + * @c: UBIFS file-system description object + * @zroot: root of the index + * + * This function records information about the index that will be needed for the + * next old index check i.e. 'dbg_check_old_index()'. + * + * This function returns %0 on success and a negative error code on failure. + */ +int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot) +{ + struct ubifs_idx_node *idx; + int lnum, offs, len, err = 0; + struct ubifs_debug_info *d = c->dbg; + + d->old_zroot = *zroot; + lnum = d->old_zroot.lnum; + offs = d->old_zroot.offs; + len = d->old_zroot.len; + + idx = kmalloc(c->max_idx_node_sz, GFP_NOFS); + if (!idx) + return -ENOMEM; + + err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs); + if (err) + goto out; + + d->old_zroot_level = le16_to_cpu(idx->level); + d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum); +out: + kfree(idx); + return err; +} + +/** + * dbg_check_old_index - check the old copy of the index. + * @c: UBIFS file-system description object + * @zroot: root of the new index + * + * In order to be able to recover from an unclean unmount, a complete copy of + * the index must exist on flash. This is the "old" index. The commit process + * must write the "new" index to flash without overwriting or destroying any + * part of the old index. This function is run at commit end in order to check + * that the old index does indeed exist completely intact. + * + * This function returns %0 on success and a negative error code on failure. + */ +int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot) +{ + int lnum, offs, len, err = 0, last_level, child_cnt; + int first = 1, iip; + struct ubifs_debug_info *d = c->dbg; + union ubifs_key lower_key, upper_key, l_key, u_key; + unsigned long long last_sqnum; + struct ubifs_idx_node *idx; + struct list_head list; + struct idx_node *i; + size_t sz; + + if (!dbg_is_chk_index(c)) + return 0; + + INIT_LIST_HEAD(&list); + + sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) - + UBIFS_IDX_NODE_SZ; + + /* Start at the old zroot */ + lnum = d->old_zroot.lnum; + offs = d->old_zroot.offs; + len = d->old_zroot.len; + iip = 0; + + /* + * Traverse the index tree preorder depth-first i.e. do a node and then + * its subtrees from left to right. + */ + while (1) { + struct ubifs_branch *br; + + /* Get the next index node */ + i = kmalloc(sz, GFP_NOFS); + if (!i) { + err = -ENOMEM; + goto out_free; + } + i->iip = iip; + /* Keep the index nodes on our path in a linked list */ + list_add_tail(&i->list, &list); + /* Read the index node */ + idx = &i->idx; + err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs); + if (err) + goto out_free; + /* Validate index node */ + child_cnt = le16_to_cpu(idx->child_cnt); + if (child_cnt < 1 || child_cnt > c->fanout) { + err = 1; + goto out_dump; + } + if (first) { + first = 0; + /* Check root level and sqnum */ + if (le16_to_cpu(idx->level) != d->old_zroot_level) { + err = 2; + goto out_dump; + } + if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) { + err = 3; + goto out_dump; + } + /* Set last values as though root had a parent */ + last_level = le16_to_cpu(idx->level) + 1; + last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1; + key_read(c, ubifs_idx_key(c, idx), &lower_key); + highest_ino_key(c, &upper_key, INUM_WATERMARK); + } + key_copy(c, &upper_key, &i->upper_key); + if (le16_to_cpu(idx->level) != last_level - 1) { + err = 3; + goto out_dump; + } + /* + * The index is always written bottom up hence a child's sqnum + * is always less than the parents. + */ + if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) { + err = 4; + goto out_dump; + } + /* Check key range */ + key_read(c, ubifs_idx_key(c, idx), &l_key); + br = ubifs_idx_branch(c, idx, child_cnt - 1); + key_read(c, &br->key, &u_key); + if (keys_cmp(c, &lower_key, &l_key) > 0) { + err = 5; + goto out_dump; + } + if (keys_cmp(c, &upper_key, &u_key) < 0) { + err = 6; + goto out_dump; + } + if (keys_cmp(c, &upper_key, &u_key) == 0) + if (!is_hash_key(c, &u_key)) { + err = 7; + goto out_dump; + } + /* Go to next index node */ + if (le16_to_cpu(idx->level) == 0) { + /* At the bottom, so go up until can go right */ + while (1) { + /* Drop the bottom of the list */ + list_del(&i->list); + kfree(i); + /* No more list means we are done */ + if (list_empty(&list)) + goto out; + /* Look at the new bottom */ + i = list_entry(list.prev, struct idx_node, + list); + idx = &i->idx; + /* Can we go right */ + if (iip + 1 < le16_to_cpu(idx->child_cnt)) { + iip = iip + 1; + break; + } else + /* Nope, so go up again */ + iip = i->iip; + } + } else + /* Go down left */ + iip = 0; + /* + * We have the parent in 'idx' and now we set up for reading the + * child pointed to by slot 'iip'. + */ + last_level = le16_to_cpu(idx->level); + last_sqnum = le64_to_cpu(idx->ch.sqnum); + br = ubifs_idx_branch(c, idx, iip); + lnum = le32_to_cpu(br->lnum); + offs = le32_to_cpu(br->offs); + len = le32_to_cpu(br->len); + key_read(c, &br->key, &lower_key); + if (iip + 1 < le16_to_cpu(idx->child_cnt)) { + br = ubifs_idx_branch(c, idx, iip + 1); + key_read(c, &br->key, &upper_key); + } else + key_copy(c, &i->upper_key, &upper_key); + } +out: + err = dbg_old_index_check_init(c, zroot); + if (err) + goto out_free; + + return 0; + +out_dump: + ubifs_err(c, "dumping index node (iip=%d)", i->iip); + ubifs_dump_node(c, idx); + list_del(&i->list); + kfree(i); + if (!list_empty(&list)) { + i = list_entry(list.prev, struct idx_node, list); + ubifs_err(c, "dumping parent index node"); + ubifs_dump_node(c, &i->idx); + } +out_free: + while (!list_empty(&list)) { + i = list_entry(list.next, struct idx_node, list); + list_del(&i->list); + kfree(i); + } + ubifs_err(c, "failed, error %d", err); + if (err > 0) + err = -EINVAL; + return err; +} |