/*
* 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
+ * an un-mount was completed successfully. 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
}
/**
+ * 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.
+ */
+static int 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
mst = mst2;
}
- dbg_rcvry("recovered master node from LEB %d",
+ ubifs_msg("recovered master node from LEB %d",
(mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1));
memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ);
*
* 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).
+ * for subsequent empty space starting from the next @c->min_io_size boundary.
*/
static int is_last_write(const struct ubifs_info *c, void *buf, int offs)
{
- int empty_offs;
- int check_len;
+ int empty_offs, 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
+ * 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;
+ return is_empty(p, check_len);
}
/**
*
* 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).
+ * @c->min_io_size boundary.
*/
static void clean_buf(const struct ubifs_info *c, void **buf, int lnum,
int *offs, int *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;
* @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.
+ * 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)
{
- 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;
+ struct ubifs_ch *ch = buf;
+ int skip, dlen = le32_to_cpu(ch->len);
- 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;
+ /* 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;
}
- return 1;
+ /* 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;
}
/**
*
* 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.
+ * Returns %0 in case of success, %-EUCLEAN if an unrecoverable corruption is
+ * found, and a negative error code in case of failure.
*/
struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
int offs, void *sbuf, int grouped)
goto corrupted;
default:
dbg_err("unknown");
- goto corrupted;
+ err = -EINVAL;
+ goto error;
}
}
clean_buf(c, &buf, lnum, &offs, &len);
need_clean = 1;
} else {
- ubifs_err("corrupt empty space at LEB %d:%d",
- lnum, offs);
+ int corruption = first_non_ff(buf, len);
+
+ ubifs_err("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;
}
}
* 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);
+ sleb = ubifs_scan(c, next_lnum, 0, sbuf, 0);
if (IS_ERR(sleb))
return sleb;
if (sleb->nodes_cnt) {
static int recover_head(const struct ubifs_info *c, int lnum, int offs,
void *sbuf)
{
- int len, err, need_clean = 0;
+ int len, err;
if (c->min_io_size > 1)
len = c->min_io_size;
/* 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) {
+ 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 = ubi_leb_change(c->ubi, lnum, c->sbuf, len, UBI_UNKNOWN);
if (err)
goto out;
- dbg_rcvry("inode %lu at %d:%d size %lld -> %lld ", e->inum, lnum, offs,
- i_size, e->d_size);
+ dbg_rcvry("inode %lu at %d:%d size %lld -> %lld ",
+ (unsigned long)e->inum, lnum, offs, i_size, e->d_size);
return 0;
out:
ubifs_warn("inode %lu failed to fix size %lld -> %lld error %d",
- e->inum, e->i_size, e->d_size, err);
+ (unsigned long)e->inum, e->i_size, e->d_size, err);
return err;
}
return err;
if (err == -ENOENT) {
/* Remove data nodes that have no inode */
- dbg_rcvry("removing ino %lu", e->inum);
+ dbg_rcvry("removing ino %lu",
+ (unsigned long)e->inum);
err = ubifs_tnc_remove_ino(c, e->inum);
if (err)
return err;
return PTR_ERR(inode);
if (inode->i_size < e->d_size) {
dbg_rcvry("ino %lu size %lld -> %lld",
- e->inum, e->d_size,
- inode->i_size);
+ (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;
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff