md/raid10: some tidying up in fix_read_error
Currently the rdev on which a read error happened could be removed
before we perform the fix_error handling. This requires extra tests
for NULL.
So delay the rdev_dec_pending call until after the call to
fix_read_error so that we can be sure that the rdev still exists.
This allows an 'if' clause to be removed so the body gets re-indented
back one level.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 8ea0aca..8e4f469 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -271,9 +271,10 @@
*/
set_bit(R10BIO_Uptodate, &r10_bio->state);
raid_end_bio_io(r10_bio);
+ rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
} else {
/*
- * oops, read error:
+ * oops, read error - keep the refcount on the rdev
*/
char b[BDEVNAME_SIZE];
if (printk_ratelimit())
@@ -282,8 +283,6 @@
bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector);
reschedule_retry(r10_bio);
}
-
- rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
}
static void raid10_end_write_request(struct bio *bio, int error)
@@ -1438,40 +1437,33 @@
int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
int d = r10_bio->devs[r10_bio->read_slot].devnum;
- rcu_read_lock();
- rdev = rcu_dereference(conf->mirrors[d].rdev);
- if (rdev) { /* If rdev is not NULL */
- char b[BDEVNAME_SIZE];
- int cur_read_error_count = 0;
+ /* still own a reference to this rdev, so it cannot
+ * have been cleared recently.
+ */
+ rdev = conf->mirrors[d].rdev;
+ if (test_bit(Faulty, &rdev->flags))
+ /* drive has already been failed, just ignore any
+ more fix_read_error() attempts */
+ return;
+
+ check_decay_read_errors(mddev, rdev);
+ atomic_inc(&rdev->read_errors);
+ if (atomic_read(&rdev->read_errors) > max_read_errors) {
+ char b[BDEVNAME_SIZE];
bdevname(rdev->bdev, b);
- if (test_bit(Faulty, &rdev->flags)) {
- rcu_read_unlock();
- /* drive has already been failed, just ignore any
- more fix_read_error() attempts */
- return;
- }
-
- check_decay_read_errors(mddev, rdev);
- atomic_inc(&rdev->read_errors);
- cur_read_error_count = atomic_read(&rdev->read_errors);
- if (cur_read_error_count > max_read_errors) {
- rcu_read_unlock();
- printk(KERN_NOTICE
- "md/raid10:%s: %s: Raid device exceeded "
- "read_error threshold "
- "[cur %d:max %d]\n",
- mdname(mddev),
- b, cur_read_error_count, max_read_errors);
- printk(KERN_NOTICE
- "md/raid10:%s: %s: Failing raid "
- "device\n", mdname(mddev), b);
- md_error(mddev, conf->mirrors[d].rdev);
- return;
- }
+ printk(KERN_NOTICE
+ "md/raid10:%s: %s: Raid device exceeded "
+ "read_error threshold [cur %d:max %d]\n",
+ mdname(mddev), b,
+ atomic_read(&rdev->read_errors), max_read_errors);
+ printk(KERN_NOTICE
+ "md/raid10:%s: %s: Failing raid device\n",
+ mdname(mddev), b);
+ md_error(mddev, conf->mirrors[d].rdev);
+ return;
}
- rcu_read_unlock();
while(sectors) {
int s = sectors;
@@ -1540,8 +1532,8 @@
"write failed"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
- (unsigned long long)(sect+
- rdev->data_offset),
+ (unsigned long long)(
+ sect + rdev->data_offset),
bdevname(rdev->bdev, b));
printk(KERN_NOTICE "md/raid10:%s: %s: failing "
"drive\n",
@@ -1577,8 +1569,8 @@
"corrected sectors"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
- (unsigned long long)(sect+
- rdev->data_offset),
+ (unsigned long long)(
+ sect + rdev->data_offset),
bdevname(rdev->bdev, b));
printk(KERN_NOTICE "md/raid10:%s: %s: failing drive\n",
mdname(mddev),
@@ -1590,8 +1582,8 @@
"md/raid10:%s: read error corrected"
" (%d sectors at %llu on %s)\n",
mdname(mddev), s,
- (unsigned long long)(sect+
- rdev->data_offset),
+ (unsigned long long)(
+ sect + rdev->data_offset),
bdevname(rdev->bdev, b));
}
@@ -1641,7 +1633,8 @@
else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
recovery_request_write(mddev, r10_bio);
else {
- int mirror;
+ int slot = r10_bio->read_slot;
+ int mirror = r10_bio->devs[slot].devnum;
/* we got a read error. Maybe the drive is bad. Maybe just
* the block and we can fix it.
* We freeze all other IO, and try reading the block from
@@ -1655,6 +1648,7 @@
fix_read_error(conf, mddev, r10_bio);
unfreeze_array(conf);
}
+ rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
bio = r10_bio->devs[r10_bio->read_slot].bio;
r10_bio->devs[r10_bio->read_slot].bio =