Instead of having a single end_request handler that must
determine whether it was a read or a write request, we have
two separate handlers, which makes each of them easier to follow.
----------- Diffstat output ------------
./drivers/md/raid1.c | 102 +++++++++++++++++++++++++++++++++------------------
1 files changed, 66 insertions(+), 36 deletions(-)
diff ./drivers/md/raid1.c~current~ ./drivers/md/raid1.c
--- ./drivers/md/raid1.c~current~ 2004-02-06 16:18:22.000000000 +1100
+++ ./drivers/md/raid1.c 2004-02-06 16:18:22.000000000 +1100
@@ -261,7 +261,7 @@ static inline void update_head_pos(int d
r1_bio->sector + (r1_bio->master_bio->bi_size >> 9);
}
-static int raid1_end_request(struct bio *bio, unsigned int bytes_done, int error)
+static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
{
int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
@@ -271,13 +271,7 @@ static int raid1_end_request(struct bio
if (bio->bi_size)
return 1;
- if (r1_bio->cmd == READ || r1_bio->cmd == READA)
- mirror = r1_bio->read_disk;
- else {
- for (mirror = 0; mirror < conf->raid_disks; mirror++)
- if (r1_bio->write_bios[mirror] == bio)
- break;
- }
+ mirror = r1_bio->read_disk;
/*
* this branch is our 'one mirror IO has finished' event handler:
*/
@@ -296,42 +290,78 @@ static int raid1_end_request(struct bio
set_bit(R1BIO_Uptodate, &r1_bio->state);
update_head_pos(mirror, r1_bio);
- if ((r1_bio->cmd == READ) || (r1_bio->cmd == READA)) {
- if (!r1_bio->read_bio)
- BUG();
+
+ if (!r1_bio->read_bio)
+ BUG();
+ /*
+ * we have only one bio on the read side
+ */
+ if (uptodate)
+ raid_end_bio_io(r1_bio);
+ else {
/*
- * we have only one bio on the read side
+ * oops, read error:
*/
- if (uptodate)
- raid_end_bio_io(r1_bio);
- else {
- /*
- * oops, read error:
- */
- char b[BDEVNAME_SIZE];
- printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
- bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
- reschedule_retry(r1_bio);
- }
- } else {
+ char b[BDEVNAME_SIZE];
+ printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
+ bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
+ reschedule_retry(r1_bio);
+ }
- if (r1_bio->read_bio)
- BUG();
+ atomic_dec(&conf->mirrors[mirror].rdev->nr_pending);
+ return 0;
+}
+
+static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
+{
+ int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+ r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
+ int mirror;
+ conf_t *conf = mddev_to_conf(r1_bio->mddev);
+
+ if (bio->bi_size)
+ return 1;
+
+ for (mirror = 0; mirror < conf->raid_disks; mirror++)
+ if (r1_bio->write_bios[mirror] == bio)
+ break;
+
+ /*
+ * this branch is our 'one mirror IO has finished' event handler:
+ */
+ if (!uptodate)
+ md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
+ else
/*
- * WRITE:
+ * Set R1BIO_Uptodate in our master bio, so that
+ * we will return a good error code for to the higher
+ * levels even if IO on some other mirrored buffer fails.
*
- * Let's see if all mirrored write operations have finished
- * already.
+ * The 'master' represents the composite IO operation to
+ * user-side. So if something waits for IO, then it will
+ * wait for the 'master' bio.
*/
- if (atomic_dec_and_test(&r1_bio->remaining)) {
- md_write_end(r1_bio->mddev);
- raid_end_bio_io(r1_bio);
- }
- }
+ set_bit(R1BIO_Uptodate, &r1_bio->state);
+
+ update_head_pos(mirror, r1_bio);
+
+ if (r1_bio->read_bio)
+ BUG();
+ /*
+ *
+ * Let's see if all mirrored write operations have finished
+ * already.
+ */
+ if (atomic_dec_and_test(&r1_bio->remaining)) {
+ md_write_end(r1_bio->mddev);
+ raid_end_bio_io(r1_bio);
+ }
+
atomic_dec(&conf->mirrors[mirror].rdev->nr_pending);
return 0;
}
+
/*
* This routine returns the disk from which the requested read should
* be done. There is a per-array 'next expected sequential IO' sector
@@ -508,7 +538,7 @@ static int make_request(request_queue_t
read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
read_bio->bi_bdev = mirror->rdev->bdev;
- read_bio->bi_end_io = raid1_end_request;
+ read_bio->bi_end_io = raid1_end_read_request;
read_bio->bi_rw = r1_bio->cmd;
read_bio->bi_private = r1_bio;
@@ -546,7 +576,7 @@ static int make_request(request_queue_t
mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
- mbio->bi_end_io = raid1_end_request;
+ mbio->bi_end_io = raid1_end_write_request;
mbio->bi_rw = r1_bio->cmd;
mbio->bi_private = r1_bio;
-
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