[PATCH 06/10] xfs: change xfs_iwalk_grab_ichunk to use startino, not lastino

Darrick J. Wong
2019-06-04T21:50:10Z

From: Darrick J. Wong <darrick.wong@oracle.com>

Now that the inode chunk grabbing function is a static function in the
iwalk code, change its behavior so that @agino is the inode where we
want to /start/ the iteration. This reduces cognitive friction with the
callers and simplifes the code.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/xfs_iwalk.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/fs/xfs/xfs_iwalk.c b/fs/xfs/xfs_iwalk.c
index bef0c4907781..9ad017ddbae7 100644
--- a/fs/xfs/xfs_iwalk.c
+++ b/fs/xfs/xfs_iwalk.c
@@ -99,10 +99,10 @@ xfs_iwalk_ichunk_ra(
}

/*
- * Lookup the inode chunk that the given inode lives in and then get the record
- * if we found the chunk. If the inode was not the last in the chunk and there
- * are some left allocated, update the data for the pointed-to record as well as
- * return the count of grabbed inodes.
+ * Lookup the inode chunk that the given @agino lives in and then get the
+ * record if we found the chunk. Set the bits in @irec's free mask that
+ * correspond to the inodes before @agino so that we skip them. This is how we
+ * restart an inode walk that was interrupted in the middle of an inode record.
*/
STATIC int
xfs_iwalk_grab_ichunk(
@@ -113,6 +113,7 @@ xfs_iwalk_grab_ichunk(
{
int idx; /* index into inode chunk */
int stat;
+ int i;
int error = 0;

/* Lookup the inode chunk that this inode lives in */
@@ -136,24 +137,20 @@ xfs_iwalk_grab_ichunk(
return 0;
}

- idx = agino - irec->ir_startino + 1;
- if (idx < XFS_INODES_PER_CHUNK &&
- (xfs_inobt_maskn(idx, XFS_INODES_PER_CHUNK - idx) & ~irec->ir_free)) {
- int i;
+ idx = agino - irec->ir_startino;

- /* We got a right chunk with some left inodes allocated at it.
- * Grab the chunk record. Mark all the uninteresting inodes
- * free -- because they're before our start point.
- */
- for (i = 0; i < idx; i++) {
- if (XFS_INOBT_MASK(i) & ~irec->ir_free)
- irec->ir_freecount++;
- }
-
- irec->ir_free |= xfs_inobt_maskn(0, idx);
- *icount = irec->ir_count - irec->ir_freecount;
+ /*
+ * We got a right chunk with some left inodes allocated at it. Grab
+ * the chunk record. Mark all the uninteresting inodes free because
+ * they're before our start point.
+ */
+ for (i = 0; i < idx; i++) {
+ if (XFS_INOBT_MASK(i) & ~irec->ir_free)
+ irec->ir_freecount++;
}

+ irec->ir_free |= xfs_inobt_maskn(0, idx);
+ *icount = irec->ir_count - irec->ir_freecount;
return 0;
}

@@ -281,7 +278,7 @@ xfs_iwalk_ag_start(
* We require a lookup cache of at least two elements so that we don't
* have to deal with tearing down the cursor to walk the records.
*/
- error = xfs_iwalk_grab_ichunk(*curpp, agino - 1, &icount,
+ error = xfs_iwalk_grab_ichunk(*curpp, agino, &icount,
&iwag->recs[iwag->nr_recs]);
if (error)
return error;