btrfs: use super write guard in btrfs_reclaim_bgs_work()

Link: https://patch.msgid.link/20251104-work-guards-v1-2-5108ac78a171@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 5322ef2ae015e860b9ec16471a18ce2399014677..08cdda47509fa87c65f43a30d128eec48a71148e 100644 (file)
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1850,12 +1850,10 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
        if (!btrfs_should_reclaim(fs_info))
                return;
 
-       sb_start_write(fs_info->sb);
+       guard(super_write)(fs_info->sb);
 
-       if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE)) {
-               sb_end_write(fs_info->sb);
+       if (!btrfs_exclop_start(fs_info, BTRFS_EXCLOP_BALANCE))
                return;
-       }
 
        /*
         * Long running balances can keep us blocked here for eternity, so
@@ -1863,7 +1861,6 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
         */
        if (!mutex_trylock(&fs_info->reclaim_bgs_lock)) {
                btrfs_exclop_finish(fs_info);
-               sb_end_write(fs_info->sb);
                return;
        }
 
@@ -1947,7 +1944,7 @@ void btrfs_reclaim_bgs_work(struct work_struct *work)
                /*
                 * Get out fast, in case we're read-only or unmounting the
                 * filesystem. It is OK to drop block groups from the list even
-                * for the read-only case. As we did sb_start_write(),
+                * for the read-only case. As we did take the super write lock,
                 * "mount -o remount,ro" won't happen and read-only filesystem
                 * means it is forced read-only due to a fatal error. So, it
                 * never gets back to read-write to let us reclaim again.
@@ -2030,7 +2027,6 @@ end:
        list_splice_tail(&retry_list, &fs_info->reclaim_bgs);
        spin_unlock(&fs_info->unused_bgs_lock);
        btrfs_exclop_finish(fs_info);
-       sb_end_write(fs_info->sb);
 }
 
 void btrfs_reclaim_bgs(struct btrfs_fs_info *fs_info)