*
* 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);
*
* 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;
}
/**
projects / karo-tx-linux.git / blobdiff