[PATCH 11/18] UBIFS: recovery
Renaud Barbier
renaud.barbier at ge.com
Mon Dec 3 13:08:27 EST 2012
This file implements a recovery method for unclean un-mounts.
Signed-off-by: Renaud Barbier <renaud.barbier at ge.com>
---
fs/ubifs/recovery.c | 1225 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 1225 insertions(+), 0 deletions(-)
create mode 100644 fs/ubifs/recovery.c
diff --git a/fs/ubifs/recovery.c b/fs/ubifs/recovery.c
new file mode 100644
index 0000000..7444650
--- /dev/null
+++ b/fs/ubifs/recovery.c
@@ -0,0 +1,1225 @@
+/*
+ * 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 Ðртём)
+ */
+
+/*
+ * 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 ensures that the corrupted node at @offs is the last thing
+ * written to a LEB. This function returns %1 if more data is not found and
+ * %0 if more data is found.
+ */
+static int no_more_nodes(const struct ubifs_info *c, void *buf, int len,
+ int lnum, int offs)
+{
+ struct ubifs_ch *ch = buf;
+ int skip, dlen = le32_to_cpu(ch->len);
+
+ /* Check for empty space after the corrupt node's common header */
+ skip = ALIGN(offs + UBIFS_CH_SZ, c->min_io_size) - offs;
+ if (is_empty(buf + skip, len - skip))
+ return 1;
+ /*
+ * The area after the common header size is not empty, so the common
+ * header must be intact. Check it.
+ */
+ if (ubifs_check_node(c, buf, lnum, offs, 1, 0) != -EUCLEAN) {
+ dbg_rcvry("unexpected bad common header at %d:%d", lnum, offs);
+ return 0;
+ }
+ /* Now we know the corrupt node's length we can skip over it */
+ skip = ALIGN(offs + dlen, c->min_io_size) - offs;
+ /* After which there should be empty space */
+ if (is_empty(buf + skip, len - skip))
+ return 1;
+ dbg_rcvry("unexpected data at %d:%d", lnum, offs + skip);
+ return 0;
+}
+
+/**
+ * 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;
+}
--
1.7.1
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