In preparation to enhance the near mode allocation bnobt scan algorithm, lift
it into a separate function. No functional changes.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_alloc.c | 128 ++++++++++++++++++++++----------------
1 file changed, 74 insertions(+), 54 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 85e82e184ec9..c1f59bfa8d09 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -1230,6 +1230,78 @@ xfs_alloc_walk_iter(
return 0;
}
+/*
+ * Search in the by-bno btree to the left and to the right simultaneously until
+ * in each case we find a large enough free extent or run into the edge of the
+ * tree. When we run into the edge of the tree, we deactivate that cursor.
+ */
+STATIC int
+xfs_alloc_ag_vextent_bnobt(
+ struct xfs_alloc_arg *args,
+ struct xfs_alloc_cur *acur,
+ int *stat)
+{
+ struct xfs_btree_cur *fbcur = NULL;
+ int error;
+ int i;
+ bool fbinc;
+
+ ASSERT(acur->len == 0);
+ ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
+
+ *stat = 0;
+
+ error = xfs_alloc_lookup_le(acur->bnolt, args->agbno, 0, &i);
+ if (error)
+ return error;
+ error = xfs_alloc_lookup_ge(acur->bnogt, args->agbno, 0, &i);
+ if (error)
+ return error;
+
+ /*
+ * Loop going left with the leftward cursor, right with the rightward
+ * cursor, until either both directions give up or we find an entry at
+ * least as big as minlen.
+ */
+ while (xfs_alloc_cur_active(acur->bnolt) ||
+ xfs_alloc_cur_active(acur->bnogt)) {
+ error = xfs_alloc_walk_iter(args, acur, acur->bnolt, false,
+ true, 1, &i);
+ if (error)
+ return error;
+ if (i == 1) {
+ trace_xfs_alloc_cur_left(args);
+ fbcur = acur->bnogt;
+ fbinc = true;
+ break;
+ }
+
+ error = xfs_alloc_walk_iter(args, acur, acur->bnogt, true, true,
+ 1, &i);
+ if (error)
+ return error;
+ if (i == 1) {
+ trace_xfs_alloc_cur_right(args);
+ fbcur = acur->bnolt;
+ fbinc = false;
+ break;
+ }
+ }
+
+ /* search the opposite direction for a better entry */
+ if (fbcur) {
+ error = xfs_alloc_walk_iter(args, acur, fbcur, fbinc, true, -1,
+ &i);
+ if (error)
+ return error;
+ }
+
+ if (acur->len)
+ *stat = 1;
+
+ return 0;
+}
+
/*
* Allocate a variable extent near bno in the allocation group agno.
* Extent's length (returned in len) will be between minlen and maxlen,
@@ -1241,12 +1313,10 @@ xfs_alloc_ag_vextent_near(
struct xfs_alloc_arg *args)
{
struct xfs_alloc_cur acur = {0,};
- struct xfs_btree_cur *fbcur = NULL;
int error; /* error code */
int i; /* result code, temporary */
xfs_agblock_t bno;
xfs_extlen_t len;
- bool fbinc = false;
#ifdef DEBUG
/*
* Randomly don't execute the first algorithm.
@@ -1348,62 +1418,12 @@ xfs_alloc_ag_vextent_near(
}
/*
- * Second algorithm.
- * Search in the by-bno tree to the left and to the right
- * simultaneously, until in each case we find a space big enough,
- * or run into the edge of the tree. When we run into the edge,
- * we deallocate that cursor.
- * If both searches succeed, we compare the two spaces and pick
- * the better one.
- * With alignment, it's possible for both to fail; the upper
- * level algorithm that picks allocation groups for allocations
- * is not supposed to do this.
+ * Second algorithm. Search the bnobt left and right.
*/
- error = xfs_alloc_lookup_le(acur.bnolt, args->agbno, 0, &i);
- if (error)
- goto out;
- error = xfs_alloc_lookup_ge(acur.bnogt, args->agbno, 0, &i);
+ error = xfs_alloc_ag_vextent_bnobt(args, &acur, &i);
if (error)
goto out;
- /*
- * Loop going left with the leftward cursor, right with the rightward
- * cursor, until either both directions give up or we find an entry at
- * least as big as minlen.
- */
- do {
- error = xfs_alloc_walk_iter(args, &acur, acur.bnolt, false,
- true, 1, &i);
- if (error)
- goto out;
- if (i == 1) {
- trace_xfs_alloc_cur_left(args);
- fbcur = acur.bnogt;
- fbinc = true;
- break;
- }
-
- error = xfs_alloc_walk_iter(args, &acur, acur.bnogt, true, true,
- 1, &i);
- if (error)
- goto out;
- if (i == 1) {
- trace_xfs_alloc_cur_right(args);
- fbcur = acur.bnolt;
- fbinc = false;
- break;
- }
- } while (xfs_alloc_cur_active(acur.bnolt) ||
- xfs_alloc_cur_active(acur.bnogt));
-
- /* search the opposite direction for a better entry */
- if (fbcur) {
- error = xfs_alloc_walk_iter(args, &acur, fbcur, fbinc, true, -1,
- &i);
- if (error)
- goto out;
- }
-
/*
* If we couldn't get anything, give up.
*/
--
2.20.1
