@@ -1070,6 +1070,53 @@ int ubifs_clean_lebs(const struct ubifs_info *c, void *sbuf)
}
/**
+ * 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.
+ */
+static int 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) {
+ dbg_err("could not find an empty LEB");
+ dbg_dump_lprops(c);
+ dbg_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
*
@@ -1096,7 +1143,7 @@ int ubifs_rcvry_gc_commit(struct ubifs_info *c)
c->gc_lnum = -1;
if (wbuf->lnum == -1) {
dbg_rcvry("no GC head LEB");
- goto find_free;
+ return grab_empty_leb(c);
}
/*
* See whether the used space in the dirtiest LEB fits in the GC head
@@ -1104,7 +1151,7 @@ int ubifs_rcvry_gc_commit(struct ubifs_info *c)
*/
if (wbuf->offs == c->leb_size) {
dbg_rcvry("no room in GC head LEB");
- goto find_free;
+ return grab_empty_leb(c);
}
err = ubifs_find_dirty_leb(c, &lp, wbuf->offs, 2);
if (err) {
@@ -1121,7 +1168,7 @@ int ubifs_rcvry_gc_commit(struct ubifs_info *c)
*/
if (err == -ENOSPC) {
dbg_rcvry("could not find a dirty LEB");
- goto find_free;
+ return grab_empty_leb(c);
}
return err;
}
@@ -1167,30 +1214,6 @@ int ubifs_rcvry_gc_commit(struct ubifs_info *c)
return err;
dbg_rcvry("allocated LEB %d for GC", lnum);
return 0;
-
-find_free:
- /*
- * There is no GC head LEB or the free space in the GC head LEB is too
- * small, or there are not dirty LEBs. Allocate gc_lnum by calling
- * 'ubifs_find_free_leb_for_idx()' so GC is not run.
- */
- lnum = ubifs_find_free_leb_for_idx(c);
- if (lnum < 0) {
- dbg_err("could not find an empty LEB");
- dbg_dump_lprops(c);
- dbg_dump_budg(c, &c->bi);
- return lnum;
- }
- /* And 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("allocated LEB %d for GC", lnum);
- /* Run the commit */
- dbg_rcvry("committing");
- return ubifs_run_commit(c);
}
/**