From: Josef Bacik <josef@toxicpanda.com>
Date: Tue, 21 Jul 2020 10:22:12 -0400
Subject: btrfs: change nr to u64 in btrfs_start_delalloc_roots
Git-commit: b49121393f583635b78abae4037fa1e772b2a042
Patch-mainline: v5.10-rc1
References: bsc#1135481

We have btrfs_wait_ordered_roots() which takes a u64 for nr, but
btrfs_start_delalloc_roots() that takes an int for nr, which makes using
them in conjunction, especially for something like (u64)-1, annoying and
inconsistent.  Fix btrfs_start_delalloc_roots() to take a u64 for nr and
adjust start_delalloc_inodes() and it's callers appropriately.

This means we've adjusted start_delalloc_inodes() to take a pointer of
nr since we want to preserve the ability for start-delalloc_inodes() to
return an error, so simply make it do the nr adjusting as necessary.

Part of adjusting the callers to this means changing
btrfs_writeback_inodes_sb_nr() to take a u64 for items.  This may be
confusing because it seems unrelated, but the caller of
btrfs_writeback_inodes_sb_nr() already passes in a u64, it's just the
function variable that needs to be changed.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/ctree.h          |    3 +--
 fs/btrfs/delalloc-space.c |    2 +-
 fs/btrfs/dev-replace.c    |    2 +-
 fs/btrfs/inode.c          |   26 ++++++++++----------------
 fs/btrfs/ioctl.c          |    2 +-
 fs/btrfs/space-info.c     |    4 ++--
 6 files changed, 16 insertions(+), 23 deletions(-)

--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3000,8 +3000,7 @@ int btrfs_truncate_inode_items(struct bt
 			       u32 min_type);
 
 int btrfs_start_delalloc_snapshot(struct btrfs_root *root);
-int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
-			       int nr);
+int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, u64 nr);
 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
 			      unsigned int extra_bits,
 			      struct extent_state **cached_state, int dedupe);
--- a/fs/btrfs/delalloc-space.c
+++ b/fs/btrfs/delalloc-space.c
@@ -91,7 +91,7 @@ commit_trans:
 			need_commit--;
 
 			if (need_commit > 0) {
-				btrfs_start_delalloc_roots(fs_info, 0, -1);
+				btrfs_start_delalloc_roots(fs_info, U64_MAX);
 				btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
 							 (u64)-1);
 			}
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -497,7 +497,7 @@ static int btrfs_dev_replace_finishing(s
 	 * flush all outstanding I/O and inode extent mappings before the
 	 * copy operation is declared as being finished
 	 */
-	ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
+	ret = btrfs_start_delalloc_roots(fs_info, U64_MAX);
 	if (ret) {
 		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 		return ret;
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10178,7 +10178,7 @@ void btrfs_wait_and_free_delalloc_work(s
  * some fairly slow code that needs optimization. This walks the list
  * of all the inodes with pending delalloc and forces them to disk.
  */
-static int start_delalloc_inodes(struct btrfs_root *root, int nr, bool snapshot)
+static int start_delalloc_inodes(struct btrfs_root *root, u64 *nr, bool snapshot)
 {
 	struct btrfs_inode *binode;
 	struct inode *inode;
@@ -10219,9 +10219,11 @@ static int start_delalloc_inodes(struct
 		list_add_tail(&work->list, &works);
 		btrfs_queue_work(root->fs_info->flush_workers,
 				 &work->work);
-		ret++;
-		if (nr != -1 && ret >= nr)
-			goto out;
+		if (*nr != U64_MAX) {
+			(*nr)--;
+			if (*nr == 0)
+				goto out;
+		}
 		cond_resched();
 		spin_lock(&root->delalloc_lock);
 	}
@@ -10245,19 +10247,15 @@ out:
 int btrfs_start_delalloc_snapshot(struct btrfs_root *root)
 {
 	struct btrfs_fs_info *fs_info = root->fs_info;
-	int ret;
+	u64 nr = U64_MAX;
 
 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
 		return -EROFS;
 
-	ret = start_delalloc_inodes(root, -1, true);
-	if (ret > 0)
-		ret = 0;
-	return ret;
+	return start_delalloc_inodes(root, &nr, true);
 }
 
-int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput,
-			       int nr)
+int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, u64 nr)
 {
 	struct btrfs_root *root;
 	struct list_head splice;
@@ -10280,15 +10278,11 @@ int btrfs_start_delalloc_roots(struct bt
 			       &fs_info->delalloc_roots);
 		spin_unlock(&fs_info->delalloc_root_lock);
 
-		ret = start_delalloc_inodes(root, nr, false);
+		ret = start_delalloc_inodes(root, &nr, false);
 		btrfs_put_fs_root(root);
 		if (ret < 0)
 			goto out;
 
-		if (nr != -1) {
-			nr -= ret;
-			WARN_ON(nr < 0);
-		}
 		spin_lock(&fs_info->delalloc_root_lock);
 	}
 	spin_unlock(&fs_info->delalloc_root_lock);
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5594,7 +5594,7 @@ long btrfs_ioctl(struct file *file, unsi
 	case BTRFS_IOC_SYNC: {
 		int ret;
 
-		ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
+		ret = btrfs_start_delalloc_roots(fs_info, U64_MAX);
 		if (ret)
 			return ret;
 		ret = btrfs_sync_fs(inode->i_sb, 1);
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -354,7 +354,7 @@ again:
 }
 
 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
-					 unsigned long nr_pages, int nr_items)
+					 unsigned long nr_pages, u64 nr_items)
 {
 	struct super_block *sb = fs_info->sb;
 
@@ -369,7 +369,7 @@ static void btrfs_writeback_inodes_sb_nr
 		 * the filesystem is readonly(all dirty pages are written to
 		 * the disk).
 		 */
-		btrfs_start_delalloc_roots(fs_info, 0, nr_items);
+		btrfs_start_delalloc_roots(fs_info, nr_items);
 		if (!current->journal_info)
 			btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
 	}