bcachefs: Always use percpu_ref_tryget_live() on c->writes

If we're trying to get a ref and the refcount has been killed, it means
we're doing an emergency shutdown - we always want tryget_live().
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/alloc_background.c

@@ -1072,7 +1072,7 @@ static void bch2_do_discards_work(struct work_struct *work)
 
 void bch2_do_discards(struct bch_fs *c)
 {
-	if (percpu_ref_tryget(&c->writes) &&
+	if (percpu_ref_tryget_live(&c->writes) &&
 	    !queue_work(system_long_wq, &c->discard_work))
 		percpu_ref_put(&c->writes);
 }
@@ -1192,7 +1192,7 @@ static void bch2_do_invalidates_work(struct work_struct *work)
 
 void bch2_do_invalidates(struct bch_fs *c)
 {
-	if (percpu_ref_tryget(&c->writes))
+	if (percpu_ref_tryget_live(&c->writes))
 		queue_work(system_long_wq, &c->invalidate_work);
 }
 

fs/bcachefs/btree_update_interior.c

@@ -1897,7 +1897,7 @@ void bch2_btree_node_rewrite_async(struct bch_fs *c, struct btree *b)
 {
 	struct async_btree_rewrite *a;
 
-	if (!percpu_ref_tryget(&c->writes))
+	if (!percpu_ref_tryget_live(&c->writes))
 		return;
 
 	a = kmalloc(sizeof(*a), GFP_NOFS);

fs/bcachefs/btree_update_leaf.c

@@ -1108,7 +1108,7 @@ int __bch2_trans_commit(struct btree_trans *trans)
 	}
 
 	if (!(trans->flags & BTREE_INSERT_NOCHECK_RW) &&
-	    unlikely(!percpu_ref_tryget(&c->writes))) {
+	    unlikely(!percpu_ref_tryget_live(&c->writes))) {
 		ret = bch2_trans_commit_get_rw_cold(trans);
 		if (ret)
 			goto out_reset;

fs/bcachefs/ec.c

@@ -939,7 +939,7 @@ static void ec_stripe_create(struct ec_stripe_new *s)
 
 	BUG_ON(!s->allocated);
 
-	if (!percpu_ref_tryget(&c->writes))
+	if (!percpu_ref_tryget_live(&c->writes))
 		goto err;
 
 	ec_generate_ec(&s->new_stripe);

fs/bcachefs/fs-io.c

@@ -3105,7 +3105,7 @@ long bch2_fallocate_dispatch(struct file *file, int mode,
 	struct bch_fs *c = inode->v.i_sb->s_fs_info;
 	long ret;
 
-	if (!percpu_ref_tryget(&c->writes))
+	if (!percpu_ref_tryget_live(&c->writes))
 		return -EROFS;
 
 	inode_lock(&inode->v);

fs/bcachefs/io.c

@@ -1397,7 +1397,7 @@ void bch2_write(struct closure *cl)
 	}
 
 	if (c->opts.nochanges ||
-	    !percpu_ref_tryget(&c->writes)) {
+	    !percpu_ref_tryget_live(&c->writes)) {
 		op->error = -EROFS;
 		goto err;
 	}
@@ -1527,7 +1527,7 @@ static struct promote_op *__promote_alloc(struct bch_fs *c,
 	unsigned pages = DIV_ROUND_UP(sectors, PAGE_SECTORS);
 	int ret;
 
-	if (!percpu_ref_tryget(&c->writes))
+	if (!percpu_ref_tryget_live(&c->writes))
 		return NULL;
 
 	op = kzalloc(sizeof(*op) + sizeof(struct bio_vec) * pages, GFP_NOIO);

fs/bcachefs/reflink.c

@@ -282,7 +282,7 @@ s64 bch2_remap_range(struct bch_fs *c,
 	u32 dst_snapshot, src_snapshot;
 	int ret = 0, ret2 = 0;
 
-	if (!percpu_ref_tryget(&c->writes))
+	if (!percpu_ref_tryget_live(&c->writes))
 		return -EROFS;
 
 	bch2_check_set_feature(c, BCH_FEATURE_reflink);

fs/bcachefs/subvolume.c

@@ -729,7 +729,7 @@ static void bch2_delete_dead_snapshots_work(struct work_struct *work)
 
 static void bch2_delete_dead_snapshots(struct bch_fs *c)
 {
-	if (unlikely(!percpu_ref_tryget(&c->writes)))
+	if (unlikely(!percpu_ref_tryget_live(&c->writes)))
 		return;
 
 	if (!queue_work(system_long_wq, &c->snapshot_delete_work))
@@ -931,7 +931,7 @@ int bch2_subvolume_wait_for_pagecache_and_delete_hook(struct btree_trans *trans,
 	if (ret)
 		return ret;
 
-	if (unlikely(!percpu_ref_tryget(&c->writes)))
+	if (unlikely(!percpu_ref_tryget_live(&c->writes)))
 		return -EROFS;
 
 	if (!queue_work(system_long_wq, &c->snapshot_wait_for_pagecache_and_delete_work))

fs/bcachefs/sysfs.c

@@ -676,7 +676,7 @@ STORE(bch2_fs_opts_dir)
 	 * We don't need to take c->writes for correctness, but it eliminates an
 	 * unsightly error message in the dmesg log when we're RO:
 	 */
-	if (unlikely(!percpu_ref_tryget(&c->writes)))
+	if (unlikely(!percpu_ref_tryget_live(&c->writes)))
 		return -EROFS;
 
 	tmp = kstrdup(buf, GFP_KERNEL);