// 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 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 successfully. If not, the process of mounting * incorporates 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. * * The general UBIFS approach to the recovery is that it recovers from * corruptions which could be caused by power cuts, but it refuses to recover * from corruption caused by other reasons. And UBIFS tries to distinguish * between these 2 reasons of corruptions and silently recover in the former * case and loudly complain in the latter case. * * UBIFS writes only to erased LEBs, so it writes only to the flash space * containing only 0xFFs. UBIFS also always writes strictly from the beginning * of the LEB to the end. And UBIFS assumes that the underlying flash media * writes in @c->max_write_size bytes at a time. * * Hence, if UBIFS finds a corrupted node at offset X, it expects only the min. * I/O unit corresponding to offset X to contain corrupted data, all the * following min. I/O units have to contain empty space (all 0xFFs). If this is * not true, the corruption cannot be the result of a power cut, and UBIFS * refuses to mount.
*/
/** * 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.
*/ staticint 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;
}
/** * first_non_ff - find offset of the first non-0xff byte. * @buf: buffer to search in * @len: length of buffer * * This function returns offset of the first non-0xff byte in @buf or %-1 if * the buffer contains only 0xff bytes.
*/ staticint first_non_ff(void *buf, int len)
{
uint8_t *p = buf; int i;
for (i = 0; i < len; i++) if (*p++ != 0xff) return i; 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.
*/ staticint get_master_node(conststruct ubifs_info *c, int lnum, void **pbuf, struct ubifs_mst_node **mst, void **cor)
{ constint sz = c->mst_node_alsz; int err, offs, len; void *sbuf, *buf;
sbuf = vmalloc(c->leb_size); if (!sbuf) return -ENOMEM;
/* 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;
/** * 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; constint sz = c->mst_node_alsz; int err, offs1, offs2;
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;
} elseif (mst2) {
offs2 = (void *)mst2 - buf2; if (offs1 == offs2) { /* Same offset, so must be the same */ if (ubifs_compare_master_node(c, mst1, mst2)) goto out_err;
mst = mst1;
} elseif (offs2 + sz == offs1) { /* 1st LEB was written, 2nd was not */ if (cor1) goto out_err;
mst = mst1;
} elseif (offs1 == 0 &&
c->leb_size - offs2 - sz < sz) { /* 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;
}
if (c->ro_mount) { /* 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);
/* * We had to recover the master node, which means there was an * unclean reboot. However, it is possible that the master node * is clean at this point, i.e., %UBIFS_MST_DIRTY is not set. * E.g., consider the following chain of events: * * 1. UBIFS was cleanly unmounted, so the master node is clean * 2. UBIFS is being mounted R/W and starts changing the master * node in the first (%UBIFS_MST_LNUM). A power cut happens, * so this LEB ends up with some amount of garbage at the * end. * 3. UBIFS is being mounted R/O. We reach this place and * recover the master node from the second LEB * (%UBIFS_MST_LNUM + 1). But we cannot update the media * because we are being mounted R/O. We have to defer the * operation. * 4. However, this master node (@c->mst_node) is marked as * clean (since the step 1). And if we just return, the * mount code will be confused and won't recover the master * node when it is re-mounter R/W later. * * Thus, to force the recovery by marking the master node as * dirty.
*/
c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
} else { /* Write the recovered master node */
c->max_sqnum = le64_to_cpu(mst->ch.sqnum) - 1;
err = write_rcvrd_mst_node(c, c->mst_node); if (err) goto out_free;
}
vfree(buf2);
vfree(buf1);
return 0;
out_err:
err = -EINVAL;
out_free:
ubifs_err(c, "failed to recover master node"); if (mst1) {
ubifs_err(c, "dumping first master node");
ubifs_dump_node(c, mst1, c->leb_size - ((void *)mst1 - buf1));
} if (mst2) {
ubifs_err(c, "dumping second master node");
ubifs_dump_node(c, mst2, c->leb_size - ((void *)mst2 - buf2));
}
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;
/** * 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 @c->max_write_size * boundary.
*/ staticint is_last_write(conststruct ubifs_info *c, void *buf, int offs)
{ int empty_offs, check_len;
uint8_t *p;
/* * Round up to the next @c->max_write_size boundary i.e. @offs is in * the last wbuf written. After that should be empty space.
*/
empty_offs = ALIGN(offs + 1, c->max_write_size);
check_len = c->leb_size - empty_offs;
p = buf + empty_offs - offs; return is_empty(p, check_len);
}
/** * 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 * @c->min_io_size boundary.
*/ staticvoid clean_buf(conststruct ubifs_info *c, void **buf, int lnum, int *offs, int *len)
{ int empty_offs, pad_len;
dbg_rcvry("cleaning corruption at %d:%d", lnum, *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.
*/ staticint no_more_nodes(conststruct 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->max_write_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, len, 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->max_write_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
*/ staticint 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;
if (c->ro_mount && !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);
} else { /* Write the fixed LEB back to flash */ int err;
dbg_rcvry("fixing LEB %d start %d endpt %d",
lnum, start, sleb->endpt); if (endpt == 0) {
err = ubifs_leb_unmap(c, lnum); if (err) return err;
} else { int len = ALIGN(endpt, c->min_io_size);
if (start) {
err = ubifs_leb_read(c, lnum, sleb->buf, 0,
start, 1); if (err) return err;
} /* Pad to min_io_size */ if (len > endpt) { int pad_len = len - ALIGN(endpt, 8);
if (pad_len > 0) { void *buf = sleb->buf + len - pad_len;
/** * drop_last_group - drop the last group of nodes. * @sleb: scanned LEB information * @offs: offset of dropped nodes is returned here * * This is a helper function for 'ubifs_recover_leb()' which drops the last * group of nodes of the scanned LEB.
*/ staticvoid drop_last_group(struct ubifs_scan_leb *sleb, int *offs)
{ while (!list_empty(&sleb->nodes)) { struct ubifs_scan_node *snod; struct ubifs_ch *ch;
/** * drop_last_node - drop the last node. * @sleb: scanned LEB information * @offs: offset of dropped nodes is returned here * * This is a helper function for 'ubifs_recover_leb()' which drops the last * node of the scanned LEB.
*/ staticvoid drop_last_node(struct ubifs_scan_leb *sleb, int *offs)
{ struct ubifs_scan_node *snod;
if (!list_empty(&sleb->nodes)) {
snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
list);
dbg_rcvry("dropping last node at %d:%d",
sleb->lnum, snod->offs);
*offs = snod->offs;
list_del(&snod->list);
kfree(snod);
sleb->nodes_cnt -= 1;
}
}
/** * 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 * @jhead: journal head number this LEB belongs to (%-1 if the LEB does not * belong to any journal head) * * 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. * Returns the scanned information 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 jhead)
{ int ret = 0, err, len = c->leb_size - offs, start = offs, min_io_unit; int grouped = jhead == -1 ? 0 : c->jheads[jhead].grouped; struct ubifs_scan_leb *sleb; void *buf = sbuf + offs;
sleb = ubifs_start_scan(c, lnum, offs, sbuf); if (IS_ERR(sleb)) return sleb;
ubifs_assert(c, len >= 8); while (len >= 8) {
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, 1); 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;
} elseif (ret > 0) { /* Padding bytes or a valid padding node */
offs += ret;
buf += ret;
len -= ret;
} elseif (ret == SCANNED_EMPTY_SPACE ||
ret == SCANNED_GARBAGE ||
ret == SCANNED_A_BAD_PAD_NODE ||
ret == SCANNED_A_CORRUPT_NODE) {
dbg_rcvry("found corruption (%d) at %d:%d",
ret, lnum, offs); break;
} else {
ubifs_err(c, "unexpected return value %d", ret);
err = -EINVAL; goto error;
}
}
if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) { if (!is_last_write(c, buf, offs)) goto corrupted_rescan;
} elseif (ret == SCANNED_A_CORRUPT_NODE) { if (!no_more_nodes(c, buf, len, lnum, offs)) goto corrupted_rescan;
} elseif (!is_empty(buf, len)) { if (!is_last_write(c, buf, offs)) { int corruption = first_non_ff(buf, len);
/* * See header comment for this file for more * explanations about the reasons we have this check.
*/
ubifs_err(c, "corrupt empty space LEB %d:%d, corruption starts at %d",
lnum, offs, corruption); /* Make sure we dump interesting non-0xFF data */
offs += corruption;
buf += corruption; goto corrupted;
}
}
min_io_unit = round_down(offs, c->min_io_size); if (grouped) /* * If nodes are grouped, always drop the incomplete group at * the end.
*/
drop_last_group(sleb, &offs);
if (jhead == GCHD) { /* * If this LEB belongs to the GC head then while we are in the * middle of the same min. I/O unit keep dropping nodes. So * basically, what we want is to make sure that the last min. * I/O unit where we saw the corruption is dropped completely * with all the uncorrupted nodes which may possibly sit there. * * In other words, let's name the min. I/O unit where the * corruption starts B, and the previous min. I/O unit A. The * below code tries to deal with a situation when half of B * contains valid nodes or the end of a valid node, and the * second half of B contains corrupted data or garbage. This * means that UBIFS had been writing to B just before the power * cut happened. I do not know how realistic is this scenario * that half of the min. I/O unit had been written successfully * and the other half not, but this is possible in our 'failure * mode emulation' infrastructure at least. * * So what is the problem, why we need to drop those nodes? Why * can't we just clean-up the second half of B by putting a * padding node there? We can, and this works fine with one * exception which was reproduced with power cut emulation * testing and happens extremely rarely. * * Imagine the file-system is full, we run GC which starts * moving valid nodes from LEB X to LEB Y (obviously, LEB Y is * the current GC head LEB). The @c->gc_lnum is -1, which means * that GC will retain LEB X and will try to continue. Imagine * that LEB X is currently the dirtiest LEB, and the amount of * used space in LEB Y is exactly the same as amount of free * space in LEB X. * * And a power cut happens when nodes are moved from LEB X to * LEB Y. We are here trying to recover LEB Y which is the GC * head LEB. We find the min. I/O unit B as described above. * Then we clean-up LEB Y by padding min. I/O unit. And later * 'ubifs_rcvry_gc_commit()' function fails, because it cannot * find a dirty LEB which could be GC'd into LEB Y! Even LEB X * does not match because the amount of valid nodes there does * not fit the free space in LEB Y any more! And this is * because of the padding node which we added to LEB Y. The * user-visible effect of this which I once observed and * analysed is that we cannot mount the file-system with * -ENOSPC error. * * So obviously, to make sure that situation does not happen we * should free min. I/O unit B in LEB Y completely and the last * used min. I/O unit in LEB Y should be A. This is basically * what the below code tries to do.
*/ while (offs > min_io_unit)
drop_last_node(sleb, &offs);
}
/** * 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.
*/ staticint get_cs_sqnum(struct ubifs_info *c, int lnum, int offs, unsignedlonglong *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 = ubifs_leb_read(c, lnum, (void *)cs_node, offs,
UBIFS_CS_NODE_SZ, 0); 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) {
ubifs_err(c, "Not a valid node"); goto out_err;
} if (cs_node->ch.node_type != UBIFS_CS_NODE) {
ubifs_err(c, "Not 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) {
ubifs_err(c, "CS node cmt_no %llu != current cmt_no %llu",
(unsignedlonglong)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(c, "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 unclean reboots from which we are attempting to recover * (assume that only the last log LEB can be corrupted by an unclean reboot). * * 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, 0); if (IS_ERR(sleb)) return sleb; if (sleb->nodes_cnt) { struct ubifs_scan_node *snod; unsignedlonglong cs_sqnum = c->cs_sqnum;
snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list); if (cs_sqnum == 0) { int err;
/** * 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.
*/ staticint recover_head(struct ubifs_info *c, int lnum, int offs, void *sbuf)
{ int len = c->max_write_size, err;
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 = ubifs_leb_read(c, lnum, sbuf, offs, len, 1); if (err || !is_empty(sbuf, len)) {
dbg_rcvry("cleaning head at %d:%d", lnum, offs); if (offs == 0) return ubifs_leb_unmap(c, lnum);
err = ubifs_leb_read(c, lnum, sbuf, 0, offs, 1); if (err) return err; return ubifs_leb_change(c, lnum, sbuf, offs);
}
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(struct ubifs_info *c, void *sbuf)
{ int err;
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);
/** * 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.
*/ staticint clean_an_unclean_leb(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 */ return ubifs_leb_unmap(c, lnum);
}
/* 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 = ubifs_leb_change(c, lnum, sbuf, len); 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(struct ubifs_info *c, void *sbuf)
{
dbg_rcvry("recovery"); while (!list_empty(&c->unclean_leb_list)) { struct ubifs_unclean_leb *ucleb; int err;
/** * grab_empty_leb - grab an empty LEB to use as GC LEB and run commit. * @c: UBIFS file-system description object * * This is a helper function for 'ubifs_rcvry_gc_commit()' which grabs an empty * LEB to be used as GC LEB (@c->gc_lnum), and then runs the commit. Returns * zero in case of success and a negative error code in case of failure.
*/ staticint grab_empty_leb(struct ubifs_info *c)
{ int lnum, err;
/* * Note, it is very important to first search for an empty LEB and then * run the commit, not vice-versa. The reason is that there might be * only one empty LEB at the moment, the one which has been the * @c->gc_lnum just before the power cut happened. During the regular * UBIFS operation (not now) @c->gc_lnum is marked as "taken", so no * one but GC can grab it. But at this moment this single empty LEB is * not marked as taken, so if we run commit - what happens? Right, the * commit will grab it and write the index there. Remember that the * index always expands as long as there is free space, and it only * starts consolidating when we run out of space. * * IOW, if we run commit now, we might not be able to find a free LEB * after this.
*/
lnum = ubifs_find_free_leb_for_idx(c); if (lnum < 0) {
ubifs_err(c, "could not find an empty LEB");
ubifs_dump_lprops(c);
ubifs_dump_budg(c, &c->bi); return lnum;
}
/* Reset the index flag */
err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
LPROPS_INDEX, 0); if (err) return err;
c->gc_lnum = lnum;
dbg_rcvry("found empty LEB %d, run commit", lnum);
return ubifs_run_commit(c);
}
/** * ubifs_rcvry_gc_commit - recover the GC LEB number and run the commit. * @c: UBIFS file-system description object * * Out-of-place garbage collection requires always one empty LEB with which to * start garbage collection. The LEB number is recorded in c->gc_lnum and is * written to the master node on unmounting. In the case of an unclean unmount * the value of gc_lnum recorded in the master node is out of date and cannot * be used. Instead, recovery must allocate an empty LEB for this purpose. * However, there may not be enough empty space, in which case it must be * possible to GC the dirtiest LEB into the GC head LEB. * * This function also runs the commit which causes the TNC updates from * size-recovery and orphans to be written to the flash. That is important to * ensure correct replay order for subsequent mounts. * * This function returns %0 on success and a negative error code on failure.
*/ int ubifs_rcvry_gc_commit(struct ubifs_info *c)
{ struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf; struct ubifs_lprops lp; int err;
dbg_rcvry("GC head LEB %d, offs %d", wbuf->lnum, wbuf->offs);
/* * We run the commit before garbage collection otherwise subsequent * mounts will see the GC and orphan deletion in a different order.
*/
dbg_rcvry("committing");
err = ubifs_run_commit(c); if (err) return err;
dbg_rcvry("GC'ing LEB %d", lp.lnum);
mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
err = ubifs_garbage_collect_leb(c, &lp); if (err >= 0) { int err2 = ubifs_wbuf_sync_nolock(wbuf);
if (err2)
err = err2;
}
mutex_unlock(&wbuf->io_mutex); if (err < 0) {
ubifs_err(c, "GC failed, error %d", err); if (err == -EAGAIN)
err = -EINVAL; return err;
}
ubifs_assert(c, err == LEB_RETAINED); if (err != LEB_RETAINED) return -EINVAL;
err = ubifs_leb_unmap(c, c->gc_lnum); if (err) return err;
dbg_rcvry("allocated LEB %d for GC", lp.lnum); 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
*/ staticint 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;
/** * find_ino - find an entry on the size tree. * @c: UBIFS file-system description object * @inum: inode number
*/ staticstruct 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; elseif (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
*/ staticvoid 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_destroy_size_tree - free resources related to the size tree. * @c: UBIFS file-system description object
*/ void ubifs_destroy_size_tree(struct ubifs_info *c)
{ struct size_entry *e, *n;
rbtree_postorder_for_each_entry_safe(e, n, &c->size_tree, rb) {
iput(e->inode);
kfree(e);
}
c->size_tree = RB_ROOT;
}
/** * 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;
}
/** * fix_size_in_place - fix inode size in place on flash. * @c: UBIFS file-system description object * @e: inode size information for recovery
*/ staticint fix_size_in_place(struct ubifs_info *c, struct size_entry *e)
{ struct ubifs_ino_node *ino = c->sbuf; unsignedchar *p; union ubifs_key key; int err, lnum, offs, len;
loff_t i_size;
uint32_t crc;
/* Locate the inode node LEB number and offset */
ino_key_init(c, &key, e->inum);
err = ubifs_tnc_locate(c, &key, ino, &lnum, &offs); if (err) goto out; /* * If the size recorded on the inode node is greater than the size that * was calculated from nodes in the journal then don't change the inode.
*/
i_size = le64_to_cpu(ino->size); if (i_size >= e->d_size) return 0; /* Read the LEB */
err = ubifs_leb_read(c, lnum, c->sbuf, 0, c->leb_size, 1); if (err) goto out; /* Change the size field and recalculate the CRC */
ino = c->sbuf + offs;
ino->size = cpu_to_le64(e->d_size);
len = le32_to_cpu(ino->ch.len);
crc = crc32(UBIFS_CRC32_INIT, (void *)ino + 8, len - 8);
ino->ch.crc = cpu_to_le32(crc); /* Work out where data in the LEB ends and free space begins */
p = c->sbuf;
len = c->leb_size - 1; while (p[len] == 0xff)
len -= 1;
len = ALIGN(len + 1, c->min_io_size); /* Atomically write the fixed LEB back again */
err = ubifs_leb_change(c, lnum, c->sbuf, len); if (err) goto out;
dbg_rcvry("inode %lu at %d:%d size %lld -> %lld",
(unsignedlong)e->inum, lnum, offs, i_size, e->d_size); return 0;
/* * In readonly mode just keep the inode pinned in memory until we go * readwrite. In readwrite mode write the inode to the journal with the * fixed size.
*/ if (c->ro_mount) return 0;
err = ubifs_jnl_write_inode(c, inode);
iput(inode);
if (err) return err;
rb_erase(&e->rb, &c->size_tree);
kfree(e);
return 0;
}
/** * ubifs_recover_size - recover inode size. * @c: UBIFS file-system description object * @in_place: If true, do a in-place size fixup * * 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, bool in_place)
{ 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);
this = rb_next(this);
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",
(unsignedlong)e->inum);
err = ubifs_tnc_remove_ino(c, e->inum); if (err) return err;
} else { struct ubifs_ino_node *ino = c->sbuf;
