[PATCH v2 4/6] btrfs: Allow barrier_all_devices to do chunk level device check

[Qu Wenruo]

The last user of num_tolerated_disk_barrier_failures is
barrier_all_devices().
But it's can be easily changed to new per-chunk degradable check
framework.

Now btrfs_device will have two extra members, representing send/wait
error, set at write_dev_flush() time.
With these 2 new members, btrfs_check_rw_degradable() can check if the
fs is still OK when the fs is committed to disk.

Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
 fs/btrfs/disk-io.c | 15 +++++++--------
 fs/btrfs/volumes.c |  4 +++-
 fs/btrfs/volumes.h |  4 ++++
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c26b8a0b121c..f596bd130524 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3569,17 +3569,17 @@ static int barrier_all_devices(struct btrfs_fs_info 
*info)
 {
        struct list_head *head;
        struct btrfs_device *dev;
-       int errors_send = 0;
-       int errors_wait = 0;
        int ret;
 
        /* send down all the barriers */
        head = &info->fs_devices->devices;
        list_for_each_entry_rcu(dev, head, dev_list) {
+               dev->err_wait = false;
+               dev->err_send = false;
                if (dev->missing)
                        continue;
                if (!dev->bdev) {
-                       errors_send++;
+                       dev->err_send = true;
                        continue;
                }
                if (!dev->in_fs_metadata || !dev->writeable)
@@ -3587,7 +3587,7 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
 
                ret = write_dev_flush(dev, 0);
                if (ret)
-                       errors_send++;
+                       dev->err_send = true;
        }
 
        /* wait for all the barriers */
@@ -3595,7 +3595,7 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
                if (dev->missing)
                        continue;
                if (!dev->bdev) {
-                       errors_wait++;
+                       dev->err_wait = true;
                        continue;
                }
                if (!dev->in_fs_metadata || !dev->writeable)
@@ -3603,10 +3603,9 @@ static int barrier_all_devices(struct btrfs_fs_info 
*info)
 
                ret = write_dev_flush(dev, 1);
                if (ret)
-                       errors_wait++;
+                       dev->err_wait = true;
        }
-       if (errors_send > info->num_tolerated_disk_barrier_failures ||
-           errors_wait > info->num_tolerated_disk_barrier_failures)
+       if (!btrfs_check_rw_degradable(info))
                return -EIO;
        return 0;
 }
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index dd9dd94d7043..729cbd0d2b60 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6796,7 +6796,9 @@ bool btrfs_check_rw_degradable(struct btrfs_fs_info 
*fs_info)
                        btrfs_get_num_tolerated_disk_barrier_failures(
                                        map->type);
                for (i = 0; i < map->num_stripes; i++) {
-                       if (map->stripes[i].dev->missing)
+                       if (map->stripes[i].dev->missing ||
+                           map->stripes[i].dev->err_wait ||
+                           map->stripes[i].dev->err_send)
                                missing++;
                }
                if (missing > max_tolerated) {
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index db1b5ef479cf..112fccacdabc 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -75,6 +75,10 @@ struct btrfs_device {
        int can_discard;
        int is_tgtdev_for_dev_replace;
 
+       /* If this devices fails to send/wait dev flush */
+       bool err_send;
+       bool err_wait;
+
 #ifdef __BTRFS_NEED_DEVICE_DATA_ORDERED
        seqcount_t data_seqcount;
 #endif
-- 
2.12.0



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