summaryrefslogtreecommitdiff
path: root/fs/xfs
diff options
context:
space:
mode:
authorAlex Elder <aelder@sgi.com>2010-04-15 18:17:34 +0000
committerAlex Elder <aelder@sgi.com>2010-05-19 09:58:14 -0500
commit3f943d853d6ce6d808e7362e4444c7ed5f692357 (patch)
tree78ade96089353117fbcacd2a2e7297af9e652115 /fs/xfs
parente3bb2e30d532b00a9bdda997e174a9f9916cb1c0 (diff)
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: Alex Elder <aelder@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_log_recover.c31
1 files changed, 15 insertions, 16 deletions
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 7b3375db6728..3bfff4220a74 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -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 @@ validate_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);