[PATCH 06/11] md: change handle_stripe_fill6 to work in asynchronous way
Yuri Tikhonov
yur at emcraft.com
Tue Dec 9 08:57:21 EST 2008
Change handle_stripe_fill6 to work asynchronously and introduce helper
fetch_block6 function for this.
Signed-off-by: Yuri Tikhonov <yur at emcraft.com>
Signed-off-by: Ilya Yanok <yanok at emcraft.com>
---
drivers/md/raid5.c | 154 ++++++++++++++++++++++++++++++++++++----------------
1 files changed, 106 insertions(+), 48 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e31f38b..e08ed4f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2224,61 +2224,119 @@ static void handle_stripe_fill5(struct stripe_head *sh,
set_bit(STRIPE_HANDLE, &sh->state);
}
-static void handle_stripe_fill6(struct stripe_head *sh,
- struct stripe_head_state *s, struct r6_state *r6s,
- int disks)
+/* fetch_block6 - checks the given member device to see if its data needs
+ * to be read or computed to satisfy a request.
+ *
+ * Returns 1 when no more member devices need to be checked, otherwise returns
+ * 0 to tell the loop in handle_stripe_fill6 to continue
+ */
+static int fetch_block6(struct stripe_head *sh, struct stripe_head_state *s,
+ struct r6_state *r6s, int disk_idx, int disks)
{
- int i;
- for (i = disks; i--; ) {
- struct r5dev *dev = &sh->dev[i];
- if (!test_bit(R5_LOCKED, &dev->flags) &&
- !test_bit(R5_UPTODATE, &dev->flags) &&
- (dev->toread || (dev->towrite &&
- !test_bit(R5_OVERWRITE, &dev->flags)) ||
- s->syncing || s->expanding ||
- (s->failed >= 1 &&
- (sh->dev[r6s->failed_num[0]].toread ||
- s->to_write)) ||
- (s->failed >= 2 &&
- (sh->dev[r6s->failed_num[1]].toread ||
- s->to_write)))) {
- /* we would like to get this block, possibly
- * by computing it, but we might not be able to
+ struct r5dev *dev = &sh->dev[disk_idx];
+ struct r5dev *fdev[2] = { &sh->dev[r6s->failed_num[0]],
+ &sh->dev[r6s->failed_num[1]] };
+
+ if (!test_bit(R5_LOCKED, &dev->flags) &&
+ !test_bit(R5_UPTODATE, &dev->flags) &&
+ (dev->toread ||
+ (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)) ||
+ s->syncing || s->expanding ||
+ (s->failed >= 1 &&
+ (fdev[0]->toread || s->to_write)) ||
+ (s->failed >= 2 &&
+ (fdev[1]->toread || s->to_write)))) {
+ /* we would like to get this block, possibly by computing it,
+ * otherwise read it if the backing disk is insync
+ */
+ BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
+ BUG_ON(test_bit(R5_Wantread, &dev->flags));
+ if ((s->uptodate == disks - 1) &&
+ (s->failed && (disk_idx == r6s->failed_num[0] ||
+ disk_idx == r6s->failed_num[1]))) {
+ /* have disk failed, and we're requested to fetch it;
+ * do compute it
*/
- if ((s->uptodate == disks - 1) &&
- (s->failed && (i == r6s->failed_num[0] ||
- i == r6s->failed_num[1]))) {
- pr_debug("Computing stripe %llu block %d\n",
- (unsigned long long)sh->sector, i);
- compute_block_1(sh, i, 0);
- s->uptodate++;
- } else if ( s->uptodate == disks-2 && s->failed >= 2 ) {
- /* Computing 2-failure is *very* expensive; only
- * do it if failed >= 2
+ pr_debug("Computing stripe %llu block %d\n",
+ (unsigned long long)sh->sector, disk_idx);
+ set_bit(STRIPE_COMPUTE_RUN, &sh->state);
+ set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
+ set_bit(R5_Wantcompute, &dev->flags);
+ sh->ops.target = disk_idx;
+ sh->ops.target2 = -1; /* no 2nd target */
+ s->req_compute = 1;
+ s->uptodate++;
+ return 1;
+ } else if ( s->uptodate == disks-2 && s->failed >= 2 ) {
+ /* Computing 2-failure is *very* expensive; only
+ * do it if failed >= 2
+ */
+ int other;
+ for (other = disks; other--; ) {
+ if (other == disk_idx)
+ continue;
+ if (!test_bit(R5_UPTODATE,
+ &sh->dev[other].flags))
+ break;
+ }
+ BUG_ON(other < 0);
+ pr_debug("Computing stripe %llu blocks %d,%d\n",
+ (unsigned long long)sh->sector,
+ disk_idx, other);
+ set_bit(STRIPE_COMPUTE_RUN, &sh->state);
+ set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
+ if (other == r6s->qd_idx || disk_idx == r6s->qd_idx) {
+ /* a D+Q failure: compute D from P,
+ * and recompute Q then
*/
- int other;
- for (other = disks; other--; ) {
- if (other == i)
- continue;
- if (!test_bit(R5_UPTODATE,
- &sh->dev[other].flags))
- break;
- }
- BUG_ON(other < 0);
- pr_debug("Computing stripe %llu blocks %d,%d\n",
- (unsigned long long)sh->sector,
- i, other);
- compute_block_2(sh, i, other);
+ disk_idx = (other == r6s->qd_idx) ? disk_idx :
+ other;
+ set_bit(R5_Wantcompute,
+ &sh->dev[disk_idx].flags);
+ sh->ops.target = disk_idx;
+ sh->ops.target2 = -1; /* no 2nd target */
+ s->uptodate++;
+ } else {
+ /* compute both */
+ set_bit(R5_Wantcompute,
+ &sh->dev[disk_idx].flags);
+ set_bit(R5_Wantcompute, &sh->dev[other].flags);
+ sh->ops.target = disk_idx;
+ sh->ops.target2 = other;
s->uptodate += 2;
- } else if (test_bit(R5_Insync, &dev->flags)) {
- set_bit(R5_LOCKED, &dev->flags);
- set_bit(R5_Wantread, &dev->flags);
- s->locked++;
- pr_debug("Reading block %d (sync=%d)\n",
- i, s->syncing);
}
+ s->req_compute = 1;
+ return 1;
+ } else if (test_bit(R5_Insync, &dev->flags)) {
+ set_bit(R5_LOCKED, &dev->flags);
+ set_bit(R5_Wantread, &dev->flags);
+ s->locked++;
+ pr_debug("Reading block %d (sync=%d)\n",
+ disk_idx, s->syncing);
}
}
+
+ return 0;
+}
+
+/**
+ * handle_stripe_fill6 - read or compute data to satisfy pending requests.
+ */
+static void handle_stripe_fill6(struct stripe_head *sh,
+ struct stripe_head_state *s, struct r6_state *r6s,
+ int disks)
+{
+ int i;
+
+ /* look for blocks to read/compute, skip this if a compute
+ * is already in flight, or if the stripe contents are in the
+ * midst of changing due to a write
+ */
+ if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
+ !sh->reconstruct_state)
+ for (i = disks; i--; )
+ if (fetch_block6(sh, s, r6s, i, disks))
+ break;
set_bit(STRIPE_HANDLE, &sh->state);
}
--
1.5.6.1
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