/*
* 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;
*
* 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);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff