From: Josef Bacik <josef@toxicpanda.com>
Date: Thu, 22 Aug 2019 15:19:02 -0400
Subject: btrfs: use btrfs_try_granting_tickets in update_global_rsv
Git-commit: 426551f6866a369c045c77a16725f41a097fac99
Patch-mainline: v5.4-rc1
References: bsc#1165949

We have some annoying xfstests tests that will create a very small fs,
fill it up, delete it, and repeat to make sure everything works right.
This trips btrfs up sometimes because we may commit a transaction to
free space, but most of the free metadata space was being reserved by
the global reserve.  So we commit and update the global reserve, but the
space is simply added to bytes_may_use directly, instead of trying to
add it to existing tickets.  This results in ENOSPC when we really did
have space.  Fix this by calling btrfs_try_granting_tickets once we add
back our excess space to wake any pending tickets.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/block-rsv.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c
index bea66b499e6f..d07bd41a7c1e 100644
--- a/fs/btrfs/block-rsv.c
+++ b/fs/btrfs/block-rsv.c
@@ -305,6 +305,7 @@ void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)
 		btrfs_space_info_update_bytes_may_use(fs_info, sinfo,
 						      -num_bytes);
 		block_rsv->reserved = block_rsv->size;
+		btrfs_try_granting_tickets(fs_info, sinfo);
 	}
 
 	if (block_rsv->reserved == block_rsv->size)