Commit 3f943d85 authored by Alex Elder's avatar Alex Elder
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xfs: minor odds and ends in xfs_log_recover.c 



Odds and ends in "xfs_log_recover.c".  This patch just contains some
minor things that didn't seem to warrant their own individual
patches:
- In xlog_bread_noalign(), drop an assertion that a pointer is
  non-null (the crash will tell us it was a bad pointer).
- Add a more descriptive header comment for xlog_find_verify_cycle().
- Make a few additions to the comments in xlog_find_head().  Also
  rearrange some expressions in a few spots to produce the same
  result, but in a way that seems more clear what's being computed.

(Updated in response to Dave's review comments.  Note I did not
split this patch like I said I would.)

Signed-off-by: default avatarAlex Elder <aelder@sgi.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent e3bb2e30

fs/xfs/xfs_log_recover.c

+15 −16
Original line number Diff line number Diff line
@@ -167,7 +167,6 @@ xlog_bread_noalign( 


	ASSERT(nbblks > 0);

	ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));

	ASSERT(bp);



	XFS_BUF_SET_ADDR(bp, log->l_logBBstart + blk_no);

	XFS_BUF_READ(bp);
@@ -380,14 +379,12 @@ xlog_find_cycle_start( 
}



/*

 * Check that the range of blocks does not contain the cycle number

 * given.  The scan needs to occur from front to back and the ptr into the

 * region must be updated since a later routine will need to perform another

 * test.  If the region is completely good, we end up returning the same

 * last block number.

 *

 * Set blkno to -1 if we encounter no errors.  This is an invalid block number

 * since we don't ever expect logs to get this large.

 * Check that a range of blocks does not contain stop_on_cycle_no.

 * Fill in *new_blk with the block offset where such a block is

 * found, or with -1 (an invalid block number) if there is no such

 * block in the range.  The scan needs to occur from front to back

 * and the pointer into the region must be updated since a later

 * routine will need to perform another test.

 */

STATIC int

xlog_find_verify_cycle(
@@ -661,7 +658,7 @@ xlog_find_head( 
		 * In this case we want to find the first block with cycle

		 * number matching last_half_cycle.  We expect the log to be

		 * some variation on

		 *        x + 1 ... | x ...

		 *        x + 1 ... | x ... | x

		 * The first block with cycle number x (last_half_cycle) will

		 * be where the new head belongs.  First we do a binary search

		 * for the first occurrence of last_half_cycle.  The binary
@@ -671,11 +668,13 @@ xlog_find_head( 
		 * the log, then we look for occurrences of last_half_cycle - 1

		 * at the end of the log.  The cases we're looking for look

		 * like

		 *        x + 1 ... | x | x + 1 | x ...

		 *                               ^ binary search stopped here

		 *                               v binary search stopped here

		 *        x + 1 ... | x | x + 1 | x ... | x

		 *                   ^ but we want to locate this spot

		 * or

		 *        x + 1 ... | x ... | x - 1 | x

		 *        <---------> less than scan distance

		 *        x + 1 ... | x ... | x - 1 | x

		 *                           ^ we want to locate this spot

		 */

		stop_on_cycle = last_half_cycle;

		if ((error = xlog_find_cycle_start(log, bp, first_blk,
@@ -731,9 +730,9 @@ xlog_find_head( 
		 * certainly not the head of the log.  By searching for

		 * last_half_cycle-1 we accomplish that.

		 */

		start_blk = log_bbnum - num_scan_bblks + head_blk;

		ASSERT(head_blk <= INT_MAX &&

			(xfs_daddr_t) num_scan_bblks - head_blk >= 0);

			(xfs_daddr_t) num_scan_bblks >= head_blk);

		start_blk = log_bbnum - (num_scan_bblks - head_blk);

		if ((error = xlog_find_verify_cycle(log, start_blk,

					num_scan_bblks - (int)head_blk,

					(stop_on_cycle - 1), &new_blk)))
@@ -780,7 +779,7 @@ xlog_find_head( 
		if ((error = xlog_find_verify_log_record(log, start_blk,

							&head_blk, 0)) == -1) {

			/* We hit the beginning of the log during our search */

			start_blk = log_bbnum - num_scan_bblks + head_blk;

			start_blk = log_bbnum - (num_scan_bblks - head_blk);

			new_blk = log_bbnum;

			ASSERT(start_blk <= INT_MAX &&

				(xfs_daddr_t) log_bbnum-start_blk >= 0);