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Diffstat (limited to 'ubifs-utils/libubifs/journal.c')
| -rw-r--r-- | ubifs-utils/libubifs/journal.c | 633 |
1 files changed, 633 insertions, 0 deletions
diff --git a/ubifs-utils/libubifs/journal.c b/ubifs-utils/libubifs/journal.c new file mode 100644 index 0000000..e78ea14 --- /dev/null +++ b/ubifs-utils/libubifs/journal.c @@ -0,0 +1,633 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This file is part of UBIFS. + * + * Copyright (C) 2006-2008 Nokia Corporation. + * + * Authors: Artem Bityutskiy (Битюцкий Артём) + * Adrian Hunter + */ + +/* + * This file implements UBIFS journal. + * + * The journal consists of 2 parts - the log and bud LEBs. The log has fixed + * length and position, while a bud logical eraseblock is any LEB in the main + * area. Buds contain file system data - data nodes, inode nodes, etc. The log + * contains only references to buds and some other stuff like commit + * start node. The idea is that when we commit the journal, we do + * not copy the data, the buds just become indexed. Since after the commit the + * nodes in bud eraseblocks become leaf nodes of the file system index tree, we + * use term "bud". Analogy is obvious, bud eraseblocks contain nodes which will + * become leafs in the future. + * + * The journal is multi-headed because we want to write data to the journal as + * optimally as possible. It is nice to have nodes belonging to the same inode + * in one LEB, so we may write data owned by different inodes to different + * journal heads, although at present only one data head is used. + * + * For recovery reasons, the base head contains all inode nodes, all directory + * entry nodes and all truncate nodes. This means that the other heads contain + * only data nodes. + * + * Bud LEBs may be half-indexed. For example, if the bud was not full at the + * time of commit, the bud is retained to continue to be used in the journal, + * even though the "front" of the LEB is now indexed. In that case, the log + * reference contains the offset where the bud starts for the purposes of the + * journal. + * + * The journal size has to be limited, because the larger is the journal, the + * longer it takes to mount UBIFS (scanning the journal) and the more memory it + * takes (indexing in the TNC). + * + * All the journal write operations like 'ubifs_jnl_update()' here, which write + * multiple UBIFS nodes to the journal at one go, are atomic with respect to + * unclean reboots. Should the unclean reboot happen, the recovery code drops + * all the nodes. + */ + +#include "bitops.h" +#include "kmem.h" +#include "ubifs.h" +#include "defs.h" +#include "debug.h" +#include "key.h" +#include "misc.h" + +/** + * zero_ino_node_unused - zero out unused fields of an on-flash inode node. + * @ino: the inode to zero out + */ +static inline void zero_ino_node_unused(struct ubifs_ino_node *ino) +{ + memset(ino->padding1, 0, 4); + memset(ino->padding2, 0, 26); +} + +/** + * zero_dent_node_unused - zero out unused fields of an on-flash directory + * entry node. + * @dent: the directory entry to zero out + */ +static inline void zero_dent_node_unused(struct ubifs_dent_node *dent) +{ + dent->padding1 = 0; +} + +static void ubifs_add_auth_dirt(struct ubifs_info *c, int lnum) +{ + if (ubifs_authenticated(c)) + ubifs_add_dirt(c, lnum, ubifs_auth_node_sz(c)); +} + +/** + * reserve_space - reserve space in the journal. + * @c: UBIFS file-system description object + * @jhead: journal head number + * @len: node length + * + * This function reserves space in journal head @head. If the reservation + * succeeded, the journal head stays locked and later has to be unlocked using + * 'release_head()'. Returns zero in case of success, %-EAGAIN if commit has to + * be done, and other negative error codes in case of other failures. + */ +static int reserve_space(struct ubifs_info *c, int jhead, int len) +{ + int err = 0, err1, retries = 0, avail, lnum, offs, squeeze; + struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf; + + /* + * Typically, the base head has smaller nodes written to it, so it is + * better to try to allocate space at the ends of eraseblocks. This is + * what the squeeze parameter does. + */ + ubifs_assert(c, !c->ro_media && !c->ro_mount); + squeeze = (jhead == BASEHD); +again: + mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); + + if (c->ro_error) { + err = -EROFS; + goto out_unlock; + } + + avail = c->leb_size - wbuf->offs - wbuf->used; + if (wbuf->lnum != -1 && avail >= len) + return 0; + + /* + * Write buffer wasn't seek'ed or there is no enough space - look for an + * LEB with some empty space. + */ + lnum = ubifs_find_free_space(c, len, &offs, squeeze); + if (lnum >= 0) + goto out; + + err = lnum; + if (err != -ENOSPC) + goto out_unlock; + + /* + * No free space, we have to run garbage collector to make + * some. But the write-buffer mutex has to be unlocked because + * GC also takes it. + */ + dbg_jnl("no free space in jhead %s, run GC", dbg_jhead(jhead)); + mutex_unlock(&wbuf->io_mutex); + + lnum = ubifs_garbage_collect(c, 0); + if (lnum < 0) { + err = lnum; + if (err != -ENOSPC) + return err; + + /* + * GC could not make a free LEB. But someone else may + * have allocated new bud for this journal head, + * because we dropped @wbuf->io_mutex, so try once + * again. + */ + dbg_jnl("GC couldn't make a free LEB for jhead %s", + dbg_jhead(jhead)); + if (retries++ < 2) { + dbg_jnl("retry (%d)", retries); + goto again; + } + + dbg_jnl("return -ENOSPC"); + return err; + } + + mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead); + dbg_jnl("got LEB %d for jhead %s", lnum, dbg_jhead(jhead)); + avail = c->leb_size - wbuf->offs - wbuf->used; + + if (wbuf->lnum != -1 && avail >= len) { + /* + * Someone else has switched the journal head and we have + * enough space now. This happens when more than one process is + * trying to write to the same journal head at the same time. + */ + dbg_jnl("return LEB %d back, already have LEB %d:%d", + lnum, wbuf->lnum, wbuf->offs + wbuf->used); + err = ubifs_return_leb(c, lnum); + if (err) + goto out_unlock; + return 0; + } + + offs = 0; + +out: + /* + * Make sure we synchronize the write-buffer before we add the new bud + * to the log. Otherwise we may have a power cut after the log + * reference node for the last bud (@lnum) is written but before the + * write-buffer data are written to the next-to-last bud + * (@wbuf->lnum). And the effect would be that the recovery would see + * that there is corruption in the next-to-last bud. + */ + err = ubifs_wbuf_sync_nolock(wbuf); + if (err) + goto out_return; + err = ubifs_add_bud_to_log(c, jhead, lnum, offs); + if (err) + goto out_return; + err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs); + if (err) + goto out_unlock; + + return 0; + +out_unlock: + mutex_unlock(&wbuf->io_mutex); + return err; + +out_return: + /* An error occurred and the LEB has to be returned to lprops */ + ubifs_assert(c, err < 0); + err1 = ubifs_return_leb(c, lnum); + if (err1 && err == -EAGAIN) + /* + * Return original error code only if it is not %-EAGAIN, + * which is not really an error. Otherwise, return the error + * code of 'ubifs_return_leb()'. + */ + err = err1; + mutex_unlock(&wbuf->io_mutex); + return err; +} + +static int ubifs_hash_nodes(struct ubifs_info *c, void *node, + int len, struct shash_desc *hash) +{ + int auth_node_size = ubifs_auth_node_sz(c); + int err; + + while (1) { + const struct ubifs_ch *ch = node; + int nodelen = le32_to_cpu(ch->len); + + ubifs_assert(c, len >= auth_node_size); + + if (len == auth_node_size) + break; + + ubifs_assert(c, len > nodelen); + ubifs_assert(c, ch->magic == cpu_to_le32(UBIFS_NODE_MAGIC)); + + err = ubifs_shash_update(c, hash, (void *)node, nodelen); + if (err) + return err; + + node += ALIGN(nodelen, 8); + len -= ALIGN(nodelen, 8); + } + + return ubifs_prepare_auth_node(c, node, hash); +} + +/** + * write_head - write data to a journal head. + * @c: UBIFS file-system description object + * @jhead: journal head + * @buf: buffer to write + * @len: length to write + * @lnum: LEB number written is returned here + * @offs: offset written is returned here + * @sync: non-zero if the write-buffer has to by synchronized + * + * This function writes data to the reserved space of journal head @jhead. + * Returns zero in case of success and a negative error code in case of + * failure. + */ +static int write_head(struct ubifs_info *c, int jhead, void *buf, int len, + int *lnum, int *offs, int sync) +{ + int err; + struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf; + + ubifs_assert(c, jhead != GCHD); + + *lnum = c->jheads[jhead].wbuf.lnum; + *offs = c->jheads[jhead].wbuf.offs + c->jheads[jhead].wbuf.used; + dbg_jnl("jhead %s, LEB %d:%d, len %d", + dbg_jhead(jhead), *lnum, *offs, len); + + if (ubifs_authenticated(c)) { + err = ubifs_hash_nodes(c, buf, len, c->jheads[jhead].log_hash); + if (err) + return err; + } + + err = ubifs_wbuf_write_nolock(wbuf, buf, len); + if (err) + return err; + if (sync) + err = ubifs_wbuf_sync_nolock(wbuf); + return err; +} + +/** + * make_reservation - reserve journal space. + * @c: UBIFS file-system description object + * @jhead: journal head + * @len: how many bytes to reserve + * + * This function makes space reservation in journal head @jhead. The function + * takes the commit lock and locks the journal head, and the caller has to + * unlock the head and finish the reservation with 'finish_reservation()'. + * Returns zero in case of success and a negative error code in case of + * failure. + * + * Note, the journal head may be unlocked as soon as the data is written, while + * the commit lock has to be released after the data has been added to the + * TNC. + */ +static int make_reservation(struct ubifs_info *c, int jhead, int len) +{ + int err, cmt_retries = 0, nospc_retries = 0; + +again: + down_read(&c->commit_sem); + err = reserve_space(c, jhead, len); + if (!err) + /* c->commit_sem will get released via finish_reservation(). */ + return 0; + up_read(&c->commit_sem); + + if (err == -ENOSPC) { + /* + * GC could not make any progress. We should try to commit + * once because it could make some dirty space and GC would + * make progress, so make the error -EAGAIN so that the below + * will commit and re-try. + */ + if (nospc_retries++ < 2) { + dbg_jnl("no space, retry"); + err = -EAGAIN; + } + + /* + * This means that the budgeting is incorrect. We always have + * to be able to write to the media, because all operations are + * budgeted. Deletions are not budgeted, though, but we reserve + * an extra LEB for them. + */ + } + + if (err != -EAGAIN) + goto out; + + /* + * -EAGAIN means that the journal is full or too large, or the above + * code wants to do one commit. Do this and re-try. + */ + if (cmt_retries > 128) { + /* + * This should not happen unless the journal size limitations + * are too tough. + */ + ubifs_err(c, "stuck in space allocation"); + err = -ENOSPC; + goto out; + } else if (cmt_retries > 32) + ubifs_warn(c, "too many space allocation re-tries (%d)", + cmt_retries); + + dbg_jnl("-EAGAIN, commit and retry (retried %d times)", + cmt_retries); + cmt_retries += 1; + + err = ubifs_run_commit(c); + if (err) + return err; + goto again; + +out: + ubifs_err(c, "cannot reserve %d bytes in jhead %d, error %d", + len, jhead, err); + if (err == -ENOSPC) { + /* This are some budgeting problems, print useful information */ + down_write(&c->commit_sem); + dump_stack(); + ubifs_dump_budg(c, &c->bi); + ubifs_dump_lprops(c); + cmt_retries = dbg_check_lprops(c); + up_write(&c->commit_sem); + } + return err; +} + +/** + * release_head - release a journal head. + * @c: UBIFS file-system description object + * @jhead: journal head + * + * This function releases journal head @jhead which was locked by + * the 'make_reservation()' function. It has to be called after each successful + * 'make_reservation()' invocation. + */ +static inline void release_head(struct ubifs_info *c, int jhead) +{ + mutex_unlock(&c->jheads[jhead].wbuf.io_mutex); +} + +/** + * finish_reservation - finish a reservation. + * @c: UBIFS file-system description object + * + * This function finishes journal space reservation. It must be called after + * 'make_reservation()'. + */ +static void finish_reservation(struct ubifs_info *c) +{ + up_read(&c->commit_sem); +} + +/** + * ubifs_get_dent_type - translate VFS inode mode to UBIFS directory entry type. + * @mode: inode mode + */ +int ubifs_get_dent_type(int mode) +{ + switch (mode & S_IFMT) { + case S_IFREG: + return UBIFS_ITYPE_REG; + case S_IFDIR: + return UBIFS_ITYPE_DIR; + case S_IFLNK: + return UBIFS_ITYPE_LNK; + case S_IFBLK: + return UBIFS_ITYPE_BLK; + case S_IFCHR: + return UBIFS_ITYPE_CHR; + case S_IFIFO: + return UBIFS_ITYPE_FIFO; + case S_IFSOCK: + return UBIFS_ITYPE_SOCK; + default: + BUG(); + } + return 0; +} + +static void set_dent_cookie(struct ubifs_info *c, struct ubifs_dent_node *dent) +{ + if (c->double_hash) + dent->cookie = (__force __le32) get_random_u32(); + else + dent->cookie = 0; +} + +/** + * pack_inode - pack an ubifs inode node. + * @c: UBIFS file-system description object + * @ino: buffer in which to pack inode node + * @ui: ubifs inode to pack + * @last: indicates the last node of the group + */ +static void pack_inode(struct ubifs_info *c, struct ubifs_ino_node *ino, + const struct ubifs_inode *ui, int last) +{ + const struct inode *inode = &ui->vfs_inode; + int data_len = 0, last_reference = !inode->nlink; + + ino->ch.node_type = UBIFS_INO_NODE; + ino_key_init_flash(c, &ino->key, inode->inum); + ino->creat_sqnum = cpu_to_le64(ui->creat_sqnum); + ino->atime_sec = cpu_to_le64(inode->atime_sec); + ino->atime_nsec = cpu_to_le32(inode->atime_nsec); + ino->ctime_sec = cpu_to_le64(inode->ctime_sec); + ino->ctime_nsec = cpu_to_le32(inode->ctime_nsec); + ino->mtime_sec = cpu_to_le64(inode->mtime_sec); + ino->mtime_nsec = cpu_to_le32(inode->mtime_nsec); + ino->uid = cpu_to_le32(inode->uid); + ino->gid = cpu_to_le32(inode->gid); + ino->mode = cpu_to_le32(inode->mode); + ino->flags = cpu_to_le32(ui->flags); + ino->size = cpu_to_le64(ui->ui_size); + ino->nlink = cpu_to_le32(inode->nlink); + ino->compr_type = cpu_to_le16(ui->compr_type); + ino->data_len = cpu_to_le32(ui->data_len); + ino->xattr_cnt = cpu_to_le32(ui->xattr_cnt); + ino->xattr_size = cpu_to_le32(ui->xattr_size); + ino->xattr_names = cpu_to_le32(ui->xattr_names); + zero_ino_node_unused(ino); + + /* + * Drop the attached data if this is a deletion inode, the data is not + * needed anymore. + */ + if (!last_reference) { + memcpy(ino->data, ui->data, ui->data_len); + data_len = ui->data_len; + } + + ubifs_prep_grp_node(c, ino, UBIFS_INO_NODE_SZ + data_len, last); +} + +/** + * ubifs_jnl_update_file - update file. + * @c: UBIFS file-system description object + * @dir_ui: parent ubifs inode + * @nm: directory entry name + * @ui: ubifs inode to update + * + * This function updates an file by writing a directory entry node, the inode + * node itself, and the parent directory inode node to the journal. If the + * @dir_ui and @nm are NULL, only update @ui. + * + * Returns zero on success. In case of failure, a negative error code is + * returned. + */ +int ubifs_jnl_update_file(struct ubifs_info *c, + const struct ubifs_inode *dir_ui, + const struct fscrypt_name *nm, + const struct ubifs_inode *ui) +{ + const struct inode *dir = NULL, *inode = &ui->vfs_inode; + int err, dlen, ilen, len, lnum, ino_offs, dent_offs, dir_ilen; + int aligned_dlen, aligned_ilen; + struct ubifs_dent_node *dent; + struct ubifs_ino_node *ino; + union ubifs_key dent_key, ino_key; + u8 hash_dent[UBIFS_HASH_ARR_SZ]; + u8 hash_ino[UBIFS_HASH_ARR_SZ]; + u8 hash_ino_dir[UBIFS_HASH_ARR_SZ]; + + ubifs_assert(c, (!nm && !dir_ui) || (nm && dir_ui)); + ubifs_assert(c, inode->nlink != 0); + + ilen = UBIFS_INO_NODE_SZ + ui->data_len; + + if (nm) + dlen = UBIFS_DENT_NODE_SZ + fname_len(nm) + 1; + else + dlen = 0; + + if (dir_ui) { + dir = &dir_ui->vfs_inode; + ubifs_assert(c, dir->nlink != 0); + dir_ilen = UBIFS_INO_NODE_SZ + dir_ui->data_len; + } else + dir_ilen = 0; + + aligned_dlen = ALIGN(dlen, 8); + aligned_ilen = ALIGN(ilen, 8); + len = aligned_dlen + aligned_ilen + dir_ilen; + if (ubifs_authenticated(c)) + len += ALIGN(dir_ilen, 8) + ubifs_auth_node_sz(c); + + dent = kzalloc(len, GFP_NOFS); + if (!dent) + return -ENOMEM; + + /* Make reservation before allocating sequence numbers */ + err = make_reservation(c, BASEHD, len); + if (err) + goto out_free; + + if (nm) { + dent->ch.node_type = UBIFS_DENT_NODE; + dent_key_init(c, &dent_key, dir->inum, nm); + + key_write(c, &dent_key, dent->key); + dent->inum = cpu_to_le64(inode->inum); + dent->type = ubifs_get_dent_type(inode->mode); + dent->nlen = cpu_to_le16(fname_len(nm)); + memcpy(dent->name, fname_name(nm), fname_len(nm)); + dent->name[fname_len(nm)] = '\0'; + set_dent_cookie(c, dent); + + zero_dent_node_unused(dent); + ubifs_prep_grp_node(c, dent, dlen, 0); + err = ubifs_node_calc_hash(c, dent, hash_dent); + if (err) + goto out_release; + } + + ino = (void *)dent + aligned_dlen; + pack_inode(c, ino, ui, dir_ui == NULL ? 1 : 0); + err = ubifs_node_calc_hash(c, ino, hash_ino); + if (err) + goto out_release; + + if (dir_ui) { + ino = (void *)ino + aligned_ilen; + pack_inode(c, ino, dir_ui, 1); + err = ubifs_node_calc_hash(c, ino, hash_ino_dir); + if (err) + goto out_release; + } + + err = write_head(c, BASEHD, dent, len, &lnum, &dent_offs, 0); + if (err) + goto out_release; + release_head(c, BASEHD); + kfree(dent); + ubifs_add_auth_dirt(c, lnum); + + if (nm) { + err = ubifs_tnc_add_nm(c, &dent_key, lnum, dent_offs, dlen, + hash_dent, nm); + if (err) { + ubifs_assert(c, !get_failure_reason_callback(c)); + goto out_ro; + } + } + + ino_key_init(c, &ino_key, inode->inum); + ino_offs = dent_offs + aligned_dlen; + err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen, hash_ino); + if (err) { + ubifs_assert(c, !get_failure_reason_callback(c)); + goto out_ro; + } + + if (dir_ui) { + ino_key_init(c, &ino_key, dir->inum); + ino_offs += aligned_ilen; + err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, dir_ilen, + hash_ino_dir); + if (err) { + ubifs_assert(c, !get_failure_reason_callback(c)); + goto out_ro; + } + } + + finish_reservation(c); + return 0; + +out_free: + kfree(dent); + return err; + +out_release: + release_head(c, BASEHD); + kfree(dent); +out_ro: + ubifs_ro_mode(c, err); + finish_reservation(c); + return err; +} |