diff options
Diffstat (limited to 'fs/ubifs/recovery.c')
| -rw-r--r-- | fs/ubifs/recovery.c | 1249 |
1 files changed, 1249 insertions, 0 deletions
diff --git a/fs/ubifs/recovery.c b/fs/ubifs/recovery.c new file mode 100644 index 000000000..fe3b36443 --- /dev/null +++ b/fs/ubifs/recovery.c @@ -0,0 +1,1249 @@ +/* + * 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: Adrian Hunter + * Artem Bityutskiy (Битюцкий Артём) + */ + +/* + * This file implements functions needed to recover from unclean un-mounts. + * When UBIFS is mounted, it checks a flag on the master node to determine if + * an un-mount was completed sucessfully. If not, the process of mounting + * incorparates additional checking and fixing of on-flash data structures. + * UBIFS always cleans away all remnants of an unclean un-mount, so that + * errors do not accumulate. However UBIFS defers recovery if it is mounted + * read-only, and the flash is not modified in that case. + */ + +#include "ubifs.h" + +/** + * is_empty - determine whether a buffer is empty (contains all 0xff). + * @buf: buffer to clean + * @len: length of buffer + * + * This function returns %1 if the buffer is empty (contains all 0xff) otherwise + * %0 is returned. + */ +static int is_empty(void *buf, int len) +{ + uint8_t *p = buf; + int i; + + for (i = 0; i < len; i++) + if (*p++ != 0xff) + return 0; + return 1; +} + +/** + * get_master_node - get the last valid master node allowing for corruption. + * @c: UBIFS file-system description object + * @lnum: LEB number + * @pbuf: buffer containing the LEB read, is returned here + * @mst: master node, if found, is returned here + * @cor: corruption, if found, is returned here + * + * This function allocates a buffer, reads the LEB into it, and finds and + * returns the last valid master node allowing for one area of corruption. + * The corrupt area, if there is one, must be consistent with the assumption + * that it is the result of an unclean unmount while the master node was being + * written. Under those circumstances, it is valid to use the previously written + * master node. + * + * This function returns %0 on success and a negative error code on failure. + */ +static int get_master_node(const struct ubifs_info *c, int lnum, void **pbuf, + struct ubifs_mst_node **mst, void **cor) +{ + const int sz = c->mst_node_alsz; + int err, offs, len; + void *sbuf, *buf; + + sbuf = vmalloc(c->leb_size); + if (!sbuf) + return -ENOMEM; + + err = ubi_read(c->ubi, lnum, sbuf, 0, c->leb_size); + if (err && err != -EBADMSG) + goto out_free; + + /* Find the first position that is definitely not a node */ + offs = 0; + buf = sbuf; + len = c->leb_size; + while (offs + UBIFS_MST_NODE_SZ <= c->leb_size) { + struct ubifs_ch *ch = buf; + + if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) + break; + offs += sz; + buf += sz; + len -= sz; + } + /* See if there was a valid master node before that */ + if (offs) { + int ret; + + offs -= sz; + buf -= sz; + len += sz; + ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); + if (ret != SCANNED_A_NODE && offs) { + /* Could have been corruption so check one place back */ + offs -= sz; + buf -= sz; + len += sz; + ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); + if (ret != SCANNED_A_NODE) + /* + * We accept only one area of corruption because + * we are assuming that it was caused while + * trying to write a master node. + */ + goto out_err; + } + if (ret == SCANNED_A_NODE) { + struct ubifs_ch *ch = buf; + + if (ch->node_type != UBIFS_MST_NODE) + goto out_err; + dbg_rcvry("found a master node at %d:%d", lnum, offs); + *mst = buf; + offs += sz; + buf += sz; + len -= sz; + } + } + /* Check for corruption */ + if (offs < c->leb_size) { + if (!is_empty(buf, min_t(int, len, sz))) { + *cor = buf; + dbg_rcvry("found corruption at %d:%d", lnum, offs); + } + offs += sz; + buf += sz; + len -= sz; + } + /* Check remaining empty space */ + if (offs < c->leb_size) + if (!is_empty(buf, len)) + goto out_err; + *pbuf = sbuf; + return 0; + +out_err: + err = -EINVAL; +out_free: + vfree(sbuf); + *mst = NULL; + *cor = NULL; + return err; +} + +/** + * write_rcvrd_mst_node - write recovered master node. + * @c: UBIFS file-system description object + * @mst: master node + * + * This function returns %0 on success and a negative error code on failure. + */ +static int write_rcvrd_mst_node(struct ubifs_info *c, + struct ubifs_mst_node *mst) +{ + int err = 0, lnum = UBIFS_MST_LNUM, sz = c->mst_node_alsz; + __le32 save_flags; + + dbg_rcvry("recovery"); + + save_flags = mst->flags; + mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY); + + ubifs_prepare_node(c, mst, UBIFS_MST_NODE_SZ, 1); + err = ubi_leb_change(c->ubi, lnum, mst, sz, UBI_SHORTTERM); + if (err) + goto out; + err = ubi_leb_change(c->ubi, lnum + 1, mst, sz, UBI_SHORTTERM); + if (err) + goto out; +out: + mst->flags = save_flags; + return err; +} + +/** + * ubifs_recover_master_node - recover the master node. + * @c: UBIFS file-system description object + * + * This function recovers the master node from corruption that may occur due to + * an unclean unmount. + * + * This function returns %0 on success and a negative error code on failure. + */ +int ubifs_recover_master_node(struct ubifs_info *c) +{ + void *buf1 = NULL, *buf2 = NULL, *cor1 = NULL, *cor2 = NULL; + struct ubifs_mst_node *mst1 = NULL, *mst2 = NULL, *mst; + const int sz = c->mst_node_alsz; + int err, offs1, offs2; + + dbg_rcvry("recovery"); + + err = get_master_node(c, UBIFS_MST_LNUM, &buf1, &mst1, &cor1); + if (err) + goto out_free; + + err = get_master_node(c, UBIFS_MST_LNUM + 1, &buf2, &mst2, &cor2); + if (err) + goto out_free; + + if (mst1) { + offs1 = (void *)mst1 - buf1; + if ((le32_to_cpu(mst1->flags) & UBIFS_MST_RCVRY) && + (offs1 == 0 && !cor1)) { + /* + * mst1 was written by recovery at offset 0 with no + * corruption. + */ + dbg_rcvry("recovery recovery"); + mst = mst1; + } else if (mst2) { + offs2 = (void *)mst2 - buf2; + if (offs1 == offs2) { + /* Same offset, so must be the same */ + if (memcmp((void *)mst1 + UBIFS_CH_SZ, + (void *)mst2 + UBIFS_CH_SZ, + UBIFS_MST_NODE_SZ - UBIFS_CH_SZ)) + goto out_err; + mst = mst1; + } else if (offs2 + sz == offs1) { + /* 1st LEB was written, 2nd was not */ + if (cor1) + goto out_err; + mst = mst1; + } else if (offs1 == 0 && offs2 + sz >= c->leb_size) { + /* 1st LEB was unmapped and written, 2nd not */ + if (cor1) + goto out_err; + mst = mst1; + } else + goto out_err; + } else { + /* + * 2nd LEB was unmapped and about to be written, so + * there must be only one master node in the first LEB + * and no corruption. + */ + if (offs1 != 0 || cor1) + goto out_err; + mst = mst1; + } + } else { + if (!mst2) + goto out_err; + /* + * 1st LEB was unmapped and about to be written, so there must + * be no room left in 2nd LEB. + */ + offs2 = (void *)mst2 - buf2; + if (offs2 + sz + sz <= c->leb_size) + goto out_err; + mst = mst2; + } + + dbg_rcvry("recovered master node from LEB %d", + (mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1)); + + memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ); + + if ((c->vfs_sb->s_flags & MS_RDONLY)) { + /* Read-only mode. Keep a copy for switching to rw mode */ + c->rcvrd_mst_node = kmalloc(sz, GFP_KERNEL); + if (!c->rcvrd_mst_node) { + err = -ENOMEM; + goto out_free; + } + memcpy(c->rcvrd_mst_node, c->mst_node, UBIFS_MST_NODE_SZ); + } + + vfree(buf2); + vfree(buf1); + + return 0; + +out_err: + err = -EINVAL; +out_free: + ubifs_err("failed to recover master node"); + if (mst1) { + dbg_err("dumping first master node"); + dbg_dump_node(c, mst1); + } + if (mst2) { + dbg_err("dumping second master node"); + dbg_dump_node(c, mst2); + } + vfree(buf2); + vfree(buf1); + return err; +} + +/** + * ubifs_write_rcvrd_mst_node - write the recovered master node. + * @c: UBIFS file-system description object + * + * This function writes the master node that was recovered during mounting in + * read-only mode and must now be written because we are remounting rw. + * + * This function returns %0 on success and a negative error code on failure. + */ +int ubifs_write_rcvrd_mst_node(struct ubifs_info *c) +{ + int err; + + if (!c->rcvrd_mst_node) + return 0; + c->rcvrd_mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); + c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY); + err = write_rcvrd_mst_node(c, c->rcvrd_mst_node); + if (err) + return err; + kfree(c->rcvrd_mst_node); + c->rcvrd_mst_node = NULL; + return 0; +} + +/** + * is_last_write - determine if an offset was in the last write to a LEB. + * @c: UBIFS file-system description object + * @buf: buffer to check + * @offs: offset to check + * + * This function returns %1 if @offs was in the last write to the LEB whose data + * is in @buf, otherwise %0 is returned. The determination is made by checking + * for subsequent empty space starting from the next min_io_size boundary (or a + * bit less than the common header size if min_io_size is one). + */ +static int is_last_write(const struct ubifs_info *c, void *buf, int offs) +{ + int empty_offs; + int check_len; + uint8_t *p; + + if (c->min_io_size == 1) { + check_len = c->leb_size - offs; + p = buf + check_len; + for (; check_len > 0; check_len--) + if (*--p != 0xff) + break; + /* + * 'check_len' is the size of the corruption which cannot be + * more than the size of 1 node if it was caused by an unclean + * unmount. + */ + if (check_len > UBIFS_MAX_NODE_SZ) + return 0; + return 1; + } + + /* + * Round up to the next c->min_io_size boundary i.e. 'offs' is in the + * last wbuf written. After that should be empty space. + */ + empty_offs = ALIGN(offs + 1, c->min_io_size); + check_len = c->leb_size - empty_offs; + p = buf + empty_offs - offs; + + for (; check_len > 0; check_len--) + if (*p++ != 0xff) + return 0; + return 1; +} + +/** + * clean_buf - clean the data from an LEB sitting in a buffer. + * @c: UBIFS file-system description object + * @buf: buffer to clean + * @lnum: LEB number to clean + * @offs: offset from which to clean + * @len: length of buffer + * + * This function pads up to the next min_io_size boundary (if there is one) and + * sets empty space to all 0xff. @buf, @offs and @len are updated to the next + * min_io_size boundary (if there is one). + */ +static void clean_buf(const struct ubifs_info *c, void **buf, int lnum, + int *offs, int *len) +{ + int empty_offs, pad_len; + + lnum = lnum; + dbg_rcvry("cleaning corruption at %d:%d", lnum, *offs); + + if (c->min_io_size == 1) { + memset(*buf, 0xff, c->leb_size - *offs); + return; + } + + ubifs_assert(!(*offs & 7)); + empty_offs = ALIGN(*offs, c->min_io_size); + pad_len = empty_offs - *offs; + ubifs_pad(c, *buf, pad_len); + *offs += pad_len; + *buf += pad_len; + *len -= pad_len; + memset(*buf, 0xff, c->leb_size - empty_offs); +} + +/** + * no_more_nodes - determine if there are no more nodes in a buffer. + * @c: UBIFS file-system description object + * @buf: buffer to check + * @len: length of buffer + * @lnum: LEB number of the LEB from which @buf was read + * @offs: offset from which @buf was read + * + * This function scans @buf for more nodes and returns %0 is a node is found and + * %1 if no more nodes are found. + */ +static int no_more_nodes(const struct ubifs_info *c, void *buf, int len, + int lnum, int offs) +{ + int skip, next_offs = 0; + + if (len > UBIFS_DATA_NODE_SZ) { + struct ubifs_ch *ch = buf; + int dlen = le32_to_cpu(ch->len); + + if (ch->node_type == UBIFS_DATA_NODE && dlen >= UBIFS_CH_SZ && + dlen <= UBIFS_MAX_DATA_NODE_SZ) + /* The corrupt node looks like a data node */ + next_offs = ALIGN(offs + dlen, 8); + } + + if (c->min_io_size == 1) + skip = 8; + else + skip = ALIGN(offs + 1, c->min_io_size) - offs; + + offs += skip; + buf += skip; + len -= skip; + while (len > 8) { + struct ubifs_ch *ch = buf; + uint32_t magic = le32_to_cpu(ch->magic); + int ret; + + if (magic == UBIFS_NODE_MAGIC) { + ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1); + if (ret == SCANNED_A_NODE || ret > 0) { + /* + * There is a small chance this is just data in + * a data node, so check that possibility. e.g. + * this is part of a file that itself contains + * a UBIFS image. + */ + if (next_offs && offs + le32_to_cpu(ch->len) <= + next_offs) + continue; + dbg_rcvry("unexpected node at %d:%d", lnum, + offs); + return 0; + } + } + offs += 8; + buf += 8; + len -= 8; + } + return 1; +} + +/** + * fix_unclean_leb - fix an unclean LEB. + * @c: UBIFS file-system description object + * @sleb: scanned LEB information + * @start: offset where scan started + */ +static int fix_unclean_leb(struct ubifs_info *c, struct ubifs_scan_leb *sleb, + int start) +{ + int lnum = sleb->lnum, endpt = start; + + /* Get the end offset of the last node we are keeping */ + if (!list_empty(&sleb->nodes)) { + struct ubifs_scan_node *snod; + + snod = list_entry(sleb->nodes.prev, + struct ubifs_scan_node, list); + endpt = snod->offs + snod->len; + } + + if ((c->vfs_sb->s_flags & MS_RDONLY) && !c->remounting_rw) { + /* Add to recovery list */ + struct ubifs_unclean_leb *ucleb; + + dbg_rcvry("need to fix LEB %d start %d endpt %d", + lnum, start, sleb->endpt); + ucleb = kzalloc(sizeof(struct ubifs_unclean_leb), GFP_NOFS); + if (!ucleb) + return -ENOMEM; + ucleb->lnum = lnum; + ucleb->endpt = endpt; + list_add_tail(&ucleb->list, &c->unclean_leb_list); + } + return 0; +} + +/** + * drop_incomplete_group - drop nodes from an incomplete group. + * @sleb: scanned LEB information + * @offs: offset of dropped nodes is returned here + * + * This function returns %1 if nodes are dropped and %0 otherwise. + */ +static int drop_incomplete_group(struct ubifs_scan_leb *sleb, int *offs) +{ + int dropped = 0; + + while (!list_empty(&sleb->nodes)) { + struct ubifs_scan_node *snod; + struct ubifs_ch *ch; + + snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, + list); + ch = snod->node; + if (ch->group_type != UBIFS_IN_NODE_GROUP) + return dropped; + dbg_rcvry("dropping node at %d:%d", sleb->lnum, snod->offs); + *offs = snod->offs; + list_del(&snod->list); + kfree(snod); + sleb->nodes_cnt -= 1; + dropped = 1; + } + return dropped; +} + +/** + * ubifs_recover_leb - scan and recover a LEB. + * @c: UBIFS file-system description object + * @lnum: LEB number + * @offs: offset + * @sbuf: LEB-sized buffer to use + * @grouped: nodes may be grouped for recovery + * + * This function does a scan of a LEB, but caters for errors that might have + * been caused by the unclean unmount from which we are attempting to recover. + * + * This function returns %0 on success and a negative error code on failure. + */ +struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum, + int offs, void *sbuf, int grouped) +{ + int err, len = c->leb_size - offs, need_clean = 0, quiet = 1; + int empty_chkd = 0, start = offs; + struct ubifs_scan_leb *sleb; + void *buf = sbuf + offs; + + dbg_rcvry("%d:%d", lnum, offs); + + sleb = ubifs_start_scan(c, lnum, offs, sbuf); + if (IS_ERR(sleb)) + return sleb; + + if (sleb->ecc) + need_clean = 1; + + while (len >= 8) { + int ret; + + dbg_scan("look at LEB %d:%d (%d bytes left)", + lnum, offs, len); + + cond_resched(); + + /* + * Scan quietly until there is an error from which we cannot + * recover + */ + ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet); + + if (ret == SCANNED_A_NODE) { + /* A valid node, and not a padding node */ + struct ubifs_ch *ch = buf; + int node_len; + + err = ubifs_add_snod(c, sleb, buf, offs); + if (err) + goto error; + node_len = ALIGN(le32_to_cpu(ch->len), 8); + offs += node_len; + buf += node_len; + len -= node_len; + continue; + } + + if (ret > 0) { + /* Padding bytes or a valid padding node */ + offs += ret; + buf += ret; + len -= ret; + continue; + } + + if (ret == SCANNED_EMPTY_SPACE) { + if (!is_empty(buf, len)) { + if (!is_last_write(c, buf, offs)) + break; + clean_buf(c, &buf, lnum, &offs, &len); + need_clean = 1; + } + empty_chkd = 1; + break; + } + + if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) + if (is_last_write(c, buf, offs)) { + clean_buf(c, &buf, lnum, &offs, &len); + need_clean = 1; + empty_chkd = 1; + break; + } + + if (ret == SCANNED_A_CORRUPT_NODE) + if (no_more_nodes(c, buf, len, lnum, offs)) { + clean_buf(c, &buf, lnum, &offs, &len); + need_clean = 1; + empty_chkd = 1; + break; + } + + if (quiet) { + /* Redo the last scan but noisily */ + quiet = 0; + continue; + } + + switch (ret) { + case SCANNED_GARBAGE: + dbg_err("garbage"); + goto corrupted; + case SCANNED_A_CORRUPT_NODE: + case SCANNED_A_BAD_PAD_NODE: + dbg_err("bad node"); + goto corrupted; + default: + dbg_err("unknown"); + goto corrupted; + } + } + + if (!empty_chkd && !is_empty(buf, len)) { + if (is_last_write(c, buf, offs)) { + clean_buf(c, &buf, lnum, &offs, &len); + need_clean = 1; + } else { + ubifs_err("corrupt empty space at LEB %d:%d", + lnum, offs); + goto corrupted; + } + } + + /* Drop nodes from incomplete group */ + if (grouped && drop_incomplete_group(sleb, &offs)) { + buf = sbuf + offs; + len = c->leb_size - offs; + clean_buf(c, &buf, lnum, &offs, &len); + need_clean = 1; + } + + if (offs % c->min_io_size) { + clean_buf(c, &buf, lnum, &offs, &len); + need_clean = 1; + } + + ubifs_end_scan(c, sleb, lnum, offs); + + if (need_clean) { + err = fix_unclean_leb(c, sleb, start); + if (err) + goto error; + } + + return sleb; + +corrupted: + ubifs_scanned_corruption(c, lnum, offs, buf); + err = -EUCLEAN; +error: + ubifs_err("LEB %d scanning failed", lnum); + ubifs_scan_destroy(sleb); + return ERR_PTR(err); +} + +/** + * get_cs_sqnum - get commit start sequence number. + * @c: UBIFS file-system description object + * @lnum: LEB number of commit start node + * @offs: offset of commit start node + * @cs_sqnum: commit start sequence number is returned here + * + * This function returns %0 on success and a negative error code on failure. + */ +static int get_cs_sqnum(struct ubifs_info *c, int lnum, int offs, + unsigned long long *cs_sqnum) +{ + struct ubifs_cs_node *cs_node = NULL; + int err, ret; + + dbg_rcvry("at %d:%d", lnum, offs); + cs_node = kmalloc(UBIFS_CS_NODE_SZ, GFP_KERNEL); + if (!cs_node) + return -ENOMEM; + if (c->leb_size - offs < UBIFS_CS_NODE_SZ) + goto out_err; + err = ubi_read(c->ubi, lnum, (void *)cs_node, offs, UBIFS_CS_NODE_SZ); + if (err && err != -EBADMSG) + goto out_free; + ret = ubifs_scan_a_node(c, cs_node, UBIFS_CS_NODE_SZ, lnum, offs, 0); + if (ret != SCANNED_A_NODE) { + dbg_err("Not a valid node"); + goto out_err; + } + if (cs_node->ch.node_type != UBIFS_CS_NODE) { + dbg_err("Node a CS node, type is %d", cs_node->ch.node_type); + goto out_err; + } + if (le64_to_cpu(cs_node->cmt_no) != c->cmt_no) { + dbg_err("CS node cmt_no %llu != current cmt_no %llu", + (unsigned long long)le64_to_cpu(cs_node->cmt_no), + c->cmt_no); + goto out_err; + } + *cs_sqnum = le64_to_cpu(cs_node->ch.sqnum); + dbg_rcvry("commit start sqnum %llu", *cs_sqnum); + kfree(cs_node); + return 0; + +out_err: + err = -EINVAL; +out_free: + ubifs_err("failed to get CS sqnum"); + kfree(cs_node); + return err; +} + +/** + * ubifs_recover_log_leb - scan and recover a log LEB. + * @c: UBIFS file-system description object + * @lnum: LEB number + * @offs: offset + * @sbuf: LEB-sized buffer to use + * + * This function does a scan of a LEB, but caters for errors that might have + * been caused by the unclean unmount from which we are attempting to recover. + * + * This function returns %0 on success and a negative error code on failure. + */ +struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum, + int offs, void *sbuf) +{ + struct ubifs_scan_leb *sleb; + int next_lnum; + + dbg_rcvry("LEB %d", lnum); + next_lnum = lnum + 1; + if (next_lnum >= UBIFS_LOG_LNUM + c->log_lebs) + next_lnum = UBIFS_LOG_LNUM; + if (next_lnum != c->ltail_lnum) { + /* + * We can only recover at the end of the log, so check that the + * next log LEB is empty or out of date. + */ + sleb = ubifs_scan(c, next_lnum, 0, sbuf); + if (IS_ERR(sleb)) + return sleb; + if (sleb->nodes_cnt) { + struct ubifs_scan_node *snod; + unsigned long long cs_sqnum = c->cs_sqnum; + + snod = list_entry(sleb->nodes.next, + struct ubifs_scan_node, list); + if (cs_sqnum == 0) { + int err; + + err = get_cs_sqnum(c, lnum, offs, &cs_sqnum); + if (err) { + ubifs_scan_destroy(sleb); + return ERR_PTR(err); + } + } + if (snod->sqnum > cs_sqnum) { + ubifs_err("unrecoverable log corruption " + "in LEB %d", lnum); + ubifs_scan_destroy(sleb); + return ERR_PTR(-EUCLEAN); + } + } + ubifs_scan_destroy(sleb); + } + return ubifs_recover_leb(c, lnum, offs, sbuf, 0); +} + +/** + * recover_head - recover a head. + * @c: UBIFS file-system description object + * @lnum: LEB number of head to recover + * @offs: offset of head to recover + * @sbuf: LEB-sized buffer to use + * + * This function ensures that there is no data on the flash at a head location. + * + * This function returns %0 on success and a negative error code on failure. + */ +static int recover_head(const struct ubifs_info *c, int lnum, int offs, + void *sbuf) +{ + int len, err, need_clean = 0; + + if (c->min_io_size > 1) + len = c->min_io_size; + else + len = 512; + if (offs + len > c->leb_size) + len = c->leb_size - offs; + + if (!len) + return 0; + + /* Read at the head location and check it is empty flash */ + err = ubi_read(c->ubi, lnum, sbuf, offs, len); + if (err) + need_clean = 1; + else { + uint8_t *p = sbuf; + + while (len--) + if (*p++ != 0xff) { + need_clean = 1; + break; + } + } + + if (need_clean) { + dbg_rcvry("cleaning head at %d:%d", lnum, offs); + if (offs == 0) + return ubifs_leb_unmap(c, lnum); + err = ubi_read(c->ubi, lnum, sbuf, 0, offs); + if (err) + return err; + return ubi_leb_change(c->ubi, lnum, sbuf, offs, UBI_UNKNOWN); + } + + return 0; +} + +/** + * ubifs_recover_inl_heads - recover index and LPT heads. + * @c: UBIFS file-system description object + * @sbuf: LEB-sized buffer to use + * + * This function ensures that there is no data on the flash at the index and + * LPT head locations. + * + * This deals with the recovery of a half-completed journal commit. UBIFS is + * careful never to overwrite the last version of the index or the LPT. Because + * the index and LPT are wandering trees, data from a half-completed commit will + * not be referenced anywhere in UBIFS. The data will be either in LEBs that are + * assumed to be empty and will be unmapped anyway before use, or in the index + * and LPT heads. + * + * This function returns %0 on success and a negative error code on failure. + */ +int ubifs_recover_inl_heads(const struct ubifs_info *c, void *sbuf) +{ + int err; + + ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY) || c->remounting_rw); + + dbg_rcvry("checking index head at %d:%d", c->ihead_lnum, c->ihead_offs); + err = recover_head(c, c->ihead_lnum, c->ihead_offs, sbuf); + if (err) + return err; + + dbg_rcvry("checking LPT head at %d:%d", c->nhead_lnum, c->nhead_offs); + err = recover_head(c, c->nhead_lnum, c->nhead_offs, sbuf); + if (err) + return err; + + return 0; +} + +/** + * clean_an_unclean_leb - read and write a LEB to remove corruption. + * @c: UBIFS file-system description object + * @ucleb: unclean LEB information + * @sbuf: LEB-sized buffer to use + * + * This function reads a LEB up to a point pre-determined by the mount recovery, + * checks the nodes, and writes the result back to the flash, thereby cleaning + * off any following corruption, or non-fatal ECC errors. + * + * This function returns %0 on success and a negative error code on failure. + */ +static int clean_an_unclean_leb(const struct ubifs_info *c, + struct ubifs_unclean_leb *ucleb, void *sbuf) +{ + int err, lnum = ucleb->lnum, offs = 0, len = ucleb->endpt, quiet = 1; + void *buf = sbuf; + + dbg_rcvry("LEB %d len %d", lnum, len); + + if (len == 0) { + /* Nothing to read, just unmap it */ + err = ubifs_leb_unmap(c, lnum); + if (err) + return err; + return 0; + } + + err = ubi_read(c->ubi, lnum, buf, offs, len); + if (err && err != -EBADMSG) + return err; + + while (len >= 8) { + int ret; + + cond_resched(); + + /* Scan quietly until there is an error */ + ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet); + + if (ret == SCANNED_A_NODE) { + /* A valid node, and not a padding node */ + struct ubifs_ch *ch = buf; + int node_len; + + node_len = ALIGN(le32_to_cpu(ch->len), 8); + offs += node_len; + buf += node_len; + len -= node_len; + continue; + } + + if (ret > 0) { + /* Padding bytes or a valid padding node */ + offs += ret; + buf += ret; + len -= ret; + continue; + } + + if (ret == SCANNED_EMPTY_SPACE) { + ubifs_err("unexpected empty space at %d:%d", + lnum, offs); + return -EUCLEAN; + } + + if (quiet) { + /* Redo the last scan but noisily */ + quiet = 0; + continue; + } + + ubifs_scanned_corruption(c, lnum, offs, buf); + return -EUCLEAN; + } + + /* Pad to min_io_size */ + len = ALIGN(ucleb->endpt, c->min_io_size); + if (len > ucleb->endpt) { + int pad_len = len - ALIGN(ucleb->endpt, 8); + + if (pad_len > 0) { + buf = c->sbuf + len - pad_len; + ubifs_pad(c, buf, pad_len); + } + } + + /* Write back the LEB atomically */ + err = ubi_leb_change(c->ubi, lnum, sbuf, len, UBI_UNKNOWN); + if (err) + return err; + + dbg_rcvry("cleaned LEB %d", lnum); + + return 0; +} + +/** + * ubifs_clean_lebs - clean LEBs recovered during read-only mount. + * @c: UBIFS file-system description object + * @sbuf: LEB-sized buffer to use + * + * This function cleans a LEB identified during recovery that needs to be + * written but was not because UBIFS was mounted read-only. This happens when + * remounting to read-write mode. + * + * This function returns %0 on success and a negative error code on failure. + */ +int ubifs_clean_lebs(const struct ubifs_info *c, void *sbuf) +{ + dbg_rcvry("recovery"); + while (!list_empty(&c->unclean_leb_list)) { + struct ubifs_unclean_leb *ucleb; + int err; + + ucleb = list_entry(c->unclean_leb_list.next, + struct ubifs_unclean_leb, list); + err = clean_an_unclean_leb(c, ucleb, sbuf); + if (err) + return err; + list_del(&ucleb->list); + kfree(ucleb); + } + return 0; +} + +/** + * struct size_entry - inode size information for recovery. + * @rb: link in the RB-tree of sizes + * @inum: inode number + * @i_size: size on inode + * @d_size: maximum size based on data nodes + * @exists: indicates whether the inode exists + * @inode: inode if pinned in memory awaiting rw mode to fix it + */ +struct size_entry { + struct rb_node rb; + ino_t inum; + loff_t i_size; + loff_t d_size; + int exists; + struct inode *inode; +}; + +/** + * add_ino - add an entry to the size tree. + * @c: UBIFS file-system description object + * @inum: inode number + * @i_size: size on inode + * @d_size: maximum size based on data nodes + * @exists: indicates whether the inode exists + */ +static int add_ino(struct ubifs_info *c, ino_t inum, loff_t i_size, + loff_t d_size, int exists) +{ + struct rb_node **p = &c->size_tree.rb_node, *parent = NULL; + struct size_entry *e; + + while (*p) { + parent = *p; + e = rb_entry(parent, struct size_entry, rb); + if (inum < e->inum) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + + e = kzalloc(sizeof(struct size_entry), GFP_KERNEL); + if (!e) + return -ENOMEM; + + e->inum = inum; + e->i_size = i_size; + e->d_size = d_size; + e->exists = exists; + + rb_link_node(&e->rb, parent, p); + rb_insert_color(&e->rb, &c->size_tree); + + return 0; +} + +/** + * find_ino - find an entry on the size tree. + * @c: UBIFS file-system description object + * @inum: inode number + */ +static struct size_entry *find_ino(struct ubifs_info *c, ino_t inum) +{ + struct rb_node *p = c->size_tree.rb_node; + struct size_entry *e; + + while (p) { + e = rb_entry(p, struct size_entry, rb); + if (inum < e->inum) + p = p->rb_left; + else if (inum > e->inum) + p = p->rb_right; + else + return e; + } + return NULL; +} + +/** + * remove_ino - remove an entry from the size tree. + * @c: UBIFS file-system description object + * @inum: inode number + */ +static void remove_ino(struct ubifs_info *c, ino_t inum) +{ + struct size_entry *e = find_ino(c, inum); + + if (!e) + return; + rb_erase(&e->rb, &c->size_tree); + kfree(e); +} + +/** + * ubifs_recover_size_accum - accumulate inode sizes for recovery. + * @c: UBIFS file-system description object + * @key: node key + * @deletion: node is for a deletion + * @new_size: inode size + * + * This function has two purposes: + * 1) to ensure there are no data nodes that fall outside the inode size + * 2) to ensure there are no data nodes for inodes that do not exist + * To accomplish those purposes, a rb-tree is constructed containing an entry + * for each inode number in the journal that has not been deleted, and recording + * the size from the inode node, the maximum size of any data node (also altered + * by truncations) and a flag indicating a inode number for which no inode node + * was present in the journal. + * + * Note that there is still the possibility that there are data nodes that have + * been committed that are beyond the inode size, however the only way to find + * them would be to scan the entire index. Alternatively, some provision could + * be made to record the size of inodes at the start of commit, which would seem + * very cumbersome for a scenario that is quite unlikely and the only negative + * consequence of which is wasted space. + * + * This functions returns %0 on success and a negative error code on failure. + */ +int ubifs_recover_size_accum(struct ubifs_info *c, union ubifs_key *key, + int deletion, loff_t new_size) +{ + ino_t inum = key_inum(c, key); + struct size_entry *e; + int err; + + switch (key_type(c, key)) { + case UBIFS_INO_KEY: + if (deletion) + remove_ino(c, inum); + else { + e = find_ino(c, inum); + if (e) { + e->i_size = new_size; + e->exists = 1; + } else { + err = add_ino(c, inum, new_size, 0, 1); + if (err) + return err; + } + } + break; + case UBIFS_DATA_KEY: + e = find_ino(c, inum); + if (e) { + if (new_size > e->d_size) + e->d_size = new_size; + } else { + err = add_ino(c, inum, 0, new_size, 0); + if (err) + return err; + } + break; + case UBIFS_TRUN_KEY: + e = find_ino(c, inum); + if (e) + e->d_size = new_size; + break; + } + return 0; +} + +/** + * ubifs_recover_size - recover inode size. + * @c: UBIFS file-system description object + * + * This function attempts to fix inode size discrepancies identified by the + * 'ubifs_recover_size_accum()' function. + * + * This functions returns %0 on success and a negative error code on failure. + */ +int ubifs_recover_size(struct ubifs_info *c) +{ + struct rb_node *this = rb_first(&c->size_tree); + + while (this) { + struct size_entry *e; + int err; + + e = rb_entry(this, struct size_entry, rb); + if (!e->exists) { + union ubifs_key key; + + ino_key_init(c, &key, e->inum); + err = ubifs_tnc_lookup(c, &key, c->sbuf); + if (err && err != -ENOENT) + return err; + if (err == -ENOENT) { + /* Remove data nodes that have no inode */ + dbg_rcvry("removing ino %lu", + (unsigned long)e->inum); + err = ubifs_tnc_remove_ino(c, e->inum); + if (err) + return err; + } else { + struct ubifs_ino_node *ino = c->sbuf; + + e->exists = 1; + e->i_size = le64_to_cpu(ino->size); + } + } + if (e->exists && e->i_size < e->d_size) { + if (!e->inode && (c->vfs_sb->s_flags & MS_RDONLY)) { + /* Fix the inode size and pin it in memory */ + struct inode *inode; + + inode = ubifs_iget(c->vfs_sb, e->inum); + if (IS_ERR(inode)) + return PTR_ERR(inode); + if (inode->i_size < e->d_size) { + dbg_rcvry("ino %lu size %lld -> %lld", + (unsigned long)e->inum, + e->d_size, inode->i_size); + inode->i_size = e->d_size; + ubifs_inode(inode)->ui_size = e->d_size; + e->inode = inode; + this = rb_next(this); + continue; + } + iput(inode); + } + } + this = rb_next(this); + rb_erase(&e->rb, &c->size_tree); + kfree(e); + } + return 0; +} |