f2fs: drop inode from the donation list when the last file is closed

Let's drop the inode from the donation list when there is no other
open file.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: Jaegeuk Kim

fs/f2fs/f2fs.h

@@ -876,6 +876,7 @@ struct f2fs_inode_info {
 	/* linked in global inode list for cache donation */
 	struct list_head gdonate_list;
 	pgoff_t donate_start, donate_end; /* inclusive */
+	atomic_t open_count;		/* # of open files */
 
 	struct task_struct *atomic_write_task;	/* store atomic write task */
 	struct extent_tree *extent_tree[NR_EXTENT_CACHES];
@@ -3652,6 +3653,7 @@ int f2fs_try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink);
 void f2fs_update_inode(struct inode *inode, struct folio *node_folio);
 void f2fs_update_inode_page(struct inode *inode);
 int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc);
+void f2fs_remove_donate_inode(struct inode *inode);
 void f2fs_evict_inode(struct inode *inode);
 void f2fs_handle_failed_inode(struct inode *inode);
 

fs/f2fs/file.c

@@ -628,7 +628,10 @@ static int f2fs_file_open(struct inode *inode, struct file *filp)
 	if (err)
 		return err;
 
-	return finish_preallocate_blocks(inode);
+	err = finish_preallocate_blocks(inode);
+	if (!err)
+		atomic_inc(&F2FS_I(inode)->open_count);
+	return err;
 }
 
 void f2fs_truncate_data_blocks_range(struct dnode_of_data *dn, int count)
@@ -2037,6 +2040,9 @@ static long f2fs_fallocate(struct file *file, int mode,
 
 static int f2fs_release_file(struct inode *inode, struct file *filp)
 {
+	if (atomic_dec_and_test(&F2FS_I(inode)->open_count))
+		f2fs_remove_donate_inode(inode);
+
 	/*
 	 * f2fs_release_file is called at every close calls. So we should
 	 * not drop any inmemory pages by close called by other process.

fs/f2fs/inode.c

@@ -821,7 +821,7 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc)
 	return 0;
 }
 
-static void f2fs_remove_donate_inode(struct inode *inode)
+void f2fs_remove_donate_inode(struct inode *inode)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 

fs/f2fs/super.c

@@ -1701,6 +1701,7 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
 	/* Initialize f2fs-specific inode info */
 	atomic_set(&fi->dirty_pages, 0);
 	atomic_set(&fi->i_compr_blocks, 0);
+	atomic_set(&fi->open_count, 0);
 	init_f2fs_rwsem(&fi->i_sem);
 	spin_lock_init(&fi->i_size_lock);
 	INIT_LIST_HEAD(&fi->dirty_list);