xfs: deduplicate xlog_do_recovery_pass()

In xlog_do_recovery_pass(), there are 2 distinct cases:
non-wrapped and wrapped log recovery.

If we find a wrapped log, we recover around the end
of the log, and then handle the rest of recovery
exactly as in the non-wrapped case - using exactly the same
(duplicated) code.

Rather than having the same code in both cases, we can
get the wrapped portion out of the way first if needed,
and then recover the non-wrapped portion of the log.

There should be no functional change here, just code
reorganization & deduplication.

The patch looks a bit bigger than it really is; the last
hunk is whitespace changes (un-indenting).

Tested with xfstests "check -g log" on a stock configuration.
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

fs/xfs/xfs_log_recover.c

@@ -4132,41 +4132,13 @@ xlog_do_recovery_pass(
 	}
 
 	memset(rhash, 0, sizeof(rhash));
-	if (tail_blk <= head_blk) {
-		for (blk_no = tail_blk; blk_no < head_blk; ) {
-			error = xlog_bread(log, blk_no, hblks, hbp, &offset);
-			if (error)
-				goto bread_err2;
-
-			rhead = (xlog_rec_header_t *)offset;
-			error = xlog_valid_rec_header(log, rhead, blk_no);
-			if (error)
-				goto bread_err2;
-
-			/* blocks in data section */
-			bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
-			error = xlog_bread(log, blk_no + hblks, bblks, dbp,
-					   &offset);
-			if (error)
-				goto bread_err2;
-
-			error = xlog_unpack_data(rhead, offset, log);
-			if (error)
-				goto bread_err2;
-
-			error = xlog_recover_process_data(log,
-						rhash, rhead, offset, pass);
-			if (error)
-				goto bread_err2;
-			blk_no += bblks + hblks;
-		}
-	} else {
+	blk_no = tail_blk;
+	if (tail_blk > head_blk) {
 		/*
 		 * Perform recovery around the end of the physical log.
 		 * When the head is not on the same cycle number as the tail,
-		 * we can't do a sequential recovery as above.
+		 * we can't do a sequential recovery.
 		 */
-		blk_no = tail_blk;
 		while (blk_no < log->l_logBBsize) {
 			/*
 			 * Check for header wrapping around physical end-of-log
@@ -4280,34 +4252,35 @@ xlog_do_recovery_pass(
 
 		ASSERT(blk_no >= log->l_logBBsize);
 		blk_no -= log->l_logBBsize;
+	}
 
-		/* read first part of physical log */
-		while (blk_no < head_blk) {
-			error = xlog_bread(log, blk_no, hblks, hbp, &offset);
-			if (error)
-				goto bread_err2;
+	/* read first part of physical log */
+	while (blk_no < head_blk) {
+		error = xlog_bread(log, blk_no, hblks, hbp, &offset);
+		if (error)
+			goto bread_err2;
 
-			rhead = (xlog_rec_header_t *)offset;
-			error = xlog_valid_rec_header(log, rhead, blk_no);
-			if (error)
-				goto bread_err2;
+		rhead = (xlog_rec_header_t *)offset;
+		error = xlog_valid_rec_header(log, rhead, blk_no);
+		if (error)
+			goto bread_err2;
 
-			bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
-			error = xlog_bread(log, blk_no+hblks, bblks, dbp,
-					   &offset);
-			if (error)
-				goto bread_err2;
+		/* blocks in data section */
+		bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
+		error = xlog_bread(log, blk_no+hblks, bblks, dbp,
+				   &offset);
+		if (error)
+			goto bread_err2;
 
-			error = xlog_unpack_data(rhead, offset, log);
-			if (error)
-				goto bread_err2;
+		error = xlog_unpack_data(rhead, offset, log);
+		if (error)
+			goto bread_err2;
 
-			error = xlog_recover_process_data(log, rhash,
-							rhead, offset, pass);
-			if (error)
-				goto bread_err2;
-			blk_no += bblks + hblks;
-		}
+		error = xlog_recover_process_data(log, rhash,
+						rhead, offset, pass);
+		if (error)
+			goto bread_err2;
+		blk_no += bblks + hblks;
 	}
 
  bread_err2: