| From: Naohiro Aota <naohiro.aota@wdc.com> |
| Date: Thu, 6 Jun 2019 16:54:44 +0900 |
| Subject: btrfs: start readahead also in seed devices |
| |
| commit c4e0540d0ad49c8ceab06cceed1de27c4fe29f6e upstream. |
| |
| Currently, btrfs does not consult seed devices to start readahead. As a |
| result, if readahead zone is added to the seed devices, btrfs_reada_wait() |
| indefinitely wait for the reada_ctl to finish. |
| |
| You can reproduce the hung by modifying btrfs/163 to have larger initial |
| file size (e.g. xfs_io pwrite 4M instead of current 256K). |
| |
| Fixes: 7414a03fbf9e ("btrfs: initial readahead code and prototypes") |
| Reviewed-by: Filipe Manana <fdmanana@suse.com> |
| Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> |
| Signed-off-by: David Sterba <dsterba@suse.com> |
| --- |
| fs/btrfs/reada.c | 5 +++++ |
| 1 file changed, 5 insertions(+) |
| |
| --- a/fs/btrfs/reada.c |
| +++ b/fs/btrfs/reada.c |
| @@ -764,6 +764,7 @@ static void __reada_start_machine(struct |
| u64 total = 0; |
| int i; |
| |
| +again: |
| do { |
| enqueued = 0; |
| mutex_lock(&fs_devices->device_list_mutex); |
| @@ -776,6 +777,10 @@ static void __reada_start_machine(struct |
| mutex_unlock(&fs_devices->device_list_mutex); |
| total += enqueued; |
| } while (enqueued && total < 10000); |
| + if (fs_devices->seed) { |
| + fs_devices = fs_devices->seed; |
| + goto again; |
| + } |
| |
| if (enqueued == 0) |
| return; |
