UBIFS: be more informative in failure mode

When we are testing UBIFS recovery, it is better to print in which eraseblock
we are going to fail. Currently UBIFS prints it only if recovery debugging
messages are enabled, but this is not very practical. So change 'dbg_rcvry()'
messages to 'ubifs_warn()' messages.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

fs/ubifs/debug.c

@@ -2631,11 +2631,11 @@ static int do_fail(struct ubi_volume_desc *desc, int lnum, int write)
 				d->fail_delay = 1;
 				d->fail_timeout = jiffies +
 						  msecs_to_jiffies(delay);
-				dbg_rcvry("failing after %ums", delay);
+				ubifs_warn("failing after %ums", delay);
 			} else {
 				d->fail_delay = 2;
 				d->fail_cnt_max = delay;
-				dbg_rcvry("failing after %u calls", delay);
+				ubifs_warn("failing after %u calls", delay);
 			}
 		}
 		d->fail_cnt += 1;
@@ -2653,56 +2653,56 @@ static int do_fail(struct ubi_volume_desc *desc, int lnum, int write)
 				return 0;
 		} else if (chance(19, 20))
 			return 0;
-		dbg_rcvry("failing in super block LEB %d", lnum);
+		ubifs_warn("failing in super block LEB %d", lnum);
 	} else if (lnum == UBIFS_MST_LNUM || lnum == UBIFS_MST_LNUM + 1) {
 		if (chance(19, 20))
 			return 0;
-		dbg_rcvry("failing in master LEB %d", lnum);
+		ubifs_warn("failing in master LEB %d", lnum);
 	} else if (lnum >= UBIFS_LOG_LNUM && lnum <= c->log_last) {
 		if (write) {
 			if (chance(99, 100))
 				return 0;
 		} else if (chance(399, 400))
 			return 0;
-		dbg_rcvry("failing in log LEB %d", lnum);
+		ubifs_warn("failing in log LEB %d", lnum);
 	} else if (lnum >= c->lpt_first && lnum <= c->lpt_last) {
 		if (write) {
 			if (chance(7, 8))
 				return 0;
 		} else if (chance(19, 20))
 			return 0;
-		dbg_rcvry("failing in LPT LEB %d", lnum);
+		ubifs_warn("failing in LPT LEB %d", lnum);
 	} else if (lnum >= c->orph_first && lnum <= c->orph_last) {
 		if (write) {
 			if (chance(1, 2))
 				return 0;
 		} else if (chance(9, 10))
 			return 0;
-		dbg_rcvry("failing in orphan LEB %d", lnum);
+		ubifs_warn("failing in orphan LEB %d", lnum);
 	} else if (lnum == c->ihead_lnum) {
 		if (chance(99, 100))
 			return 0;
-		dbg_rcvry("failing in index head LEB %d", lnum);
+		ubifs_warn("failing in index head LEB %d", lnum);
 	} else if (c->jheads && lnum == c->jheads[GCHD].wbuf.lnum) {
 		if (chance(9, 10))
 			return 0;
-		dbg_rcvry("failing in GC head LEB %d", lnum);
+		ubifs_warn("failing in GC head LEB %d", lnum);
 	} else if (write && !RB_EMPTY_ROOT(&c->buds) &&
 		   !ubifs_search_bud(c, lnum)) {
 		if (chance(19, 20))
 			return 0;
-		dbg_rcvry("failing in non-bud LEB %d", lnum);
+		ubifs_warn("failing in non-bud LEB %d", lnum);
 	} else if (c->cmt_state == COMMIT_RUNNING_BACKGROUND ||
 		   c->cmt_state == COMMIT_RUNNING_REQUIRED) {
 		if (chance(999, 1000))
 			return 0;
-		dbg_rcvry("failing in bud LEB %d commit running", lnum);
+		ubifs_warn("failing in bud LEB %d commit running", lnum);
 	} else {
 		if (chance(9999, 10000))
 			return 0;
-		dbg_rcvry("failing in bud LEB %d commit not running", lnum);
+		ubifs_warn("failing in bud LEB %d commit not running", lnum);
 	}
-	ubifs_err("*** SETTING FAILURE MODE ON (LEB %d) ***", lnum);
+
 	d->failure_mode = 1;
 	dump_stack();
 	return 1;
@@ -2922,8 +2922,16 @@ static ssize_t dfs_file_write(struct file *file, const char __user *u,
 	int val;
 
 	/*
-	 * FIXME: this is racy - the file-system might have already been
-	 * unmounted and we'd oops in this case.
+	 * TODO: this is racy - the file-system might have already been
+	 * unmounted and we'd oops in this case. The plan is to fix it with
+	 * help of 'iterate_supers_type()' which we should have in v3.0: when
+	 * a debugfs opened, we rember FS's UUID in file->private_data. Then
+	 * whenever we access the FS via a debugfs file, we iterate all UBIFS
+	 * superblocks and fine the one with the same UUID, and take the
+	 * locking right.
+	 *
+	 * The other way to go suggested by Al Viro is to create a separate
+	 * 'ubifs-debug' file-system instead.
 	 */
 	if (file->f_path.dentry == d->dfs_dump_lprops) {
 		dbg_dump_lprops(c);