The objective of this patch is to cleanup barrier_all_devices()
so that the error checking is in a separate loop independent of
of the loop which submits and waits on the device flush requests.
By doing this it helps to further develop patches which would tune
the error-actions as needed.
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
v2: Address Qu review comments viz..
Add meaningful names, like cp_list (for checkpoint_list head).
(And actually it does not need a new struct type just to hold
the head pointer, list node is already named as device_checkpoint).
Check return value of add_device_checkpoint()
Check if the device is already added at add_device_checkpoint()
Rename fini_devices_checkpoint() to rel_devices_checkpoint()
v3:
(resent with the correct version of the patch).
Now the flush error return is saved and checked instead of the
checkpoint of the dev_stat method earlier.
fs/btrfs/disk-io.c | 32 ++++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 420753d37e1a..3c476b118440 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3538,6 +3538,23 @@ static int write_dev_flush(struct btrfs_device *device, int wait)
return 0;
}
+static int check_barrier_error(struct btrfs_fs_devices *fsdevs)
+{
+ int dropouts = 0;
+ struct btrfs_device *dev;
+
+ list_for_each_entry_rcu(dev, &fsdevs->devices, dev_list) {
+ if (!dev->bdev || dev->last_flush_error)
+ dropouts++;
+ }
+
+ if (dropouts >
+ fsdevs->fs_info->num_tolerated_disk_barrier_failures)
+ return -EIO;
+
+ return 0;
+}
+
/*
* send an empty flush down to each device in parallel,
* then wait for them
@@ -3575,8 +3592,19 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
if (write_dev_flush(dev, 1))
dropouts++;
}
- if (dropouts > info->num_tolerated_disk_barrier_failures)
- return -EIO;
+
+ /*
+ * A slight optimization, we check for dropouts here which avoids
+ * a dev list loop when disks are healthy.
+ */
+ if (dropouts) {
+ /*
+ * As we need holistic view of the failed disks, so
+ * error checking is pushed to a separate loop.
+ */
+ return check_barrier_error(info->fs_devices);
+ }
+
return 0;
}
--
2.10.0
--
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