[PATCH] f2fs: compress: reserve blocks on released compress inode while writing

[Yangtao Li]

Reserve blocks on released compress inode while writing, so
compressed files with released space are allowed to be rewritten.

Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
---
 fs/f2fs/file.c | 86 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 51 insertions(+), 35 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 15dabeac4690..749b5af17141 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3612,39 +3612,15 @@ static int reserve_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
 	return reserved_blocks;
 }
 
-static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
+static int f2fs_reserve_file(struct inode *inode, unsigned int *blocks)
 {
-	struct inode *inode = file_inode(filp);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	pgoff_t page_idx = 0, last_idx;
 	unsigned int reserved_blocks = 0;
 	int ret;
 
-	if (!f2fs_sb_has_compression(F2FS_I_SB(inode)))
-		return -EOPNOTSUPP;
-
-	if (!f2fs_compressed_file(inode))
-		return -EINVAL;
-
-	if (f2fs_readonly(sbi->sb))
-		return -EROFS;
-
-	ret = mnt_want_write_file(filp);
-	if (ret)
-		return ret;
-
-	if (atomic_read(&F2FS_I(inode)->i_compr_blocks))
-		goto out;
-
 	f2fs_balance_fs(F2FS_I_SB(inode), true);
 
-	inode_lock(inode);
-
-	if (!is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
-		ret = -EINVAL;
-		goto unlock_inode;
-	}
-
 	f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	filemap_invalidate_lock(inode->i_mapping);
 
@@ -3688,14 +3664,8 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
 		clear_inode_flag(inode, FI_COMPRESS_RELEASED);
 		inode->i_ctime = current_time(inode);
 		f2fs_mark_inode_dirty_sync(inode, true);
-	}
-unlock_inode:
-	inode_unlock(inode);
-out:
-	mnt_drop_write_file(filp);
-
-	if (ret >= 0) {
-		ret = put_user(reserved_blocks, (u64 __user *)arg);
+		if (blocks)
+			*blocks = reserved_blocks;
 	} else if (reserved_blocks &&
 			atomic_read(&F2FS_I(inode)->i_compr_blocks)) {
 		set_sbi_flag(sbi, SBI_NEED_FSCK);
@@ -3710,6 +3680,49 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
 	return ret;
 }
 
+static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	unsigned int reserved_blocks = 0;
+	int ret;
+
+	if (!f2fs_sb_has_compression(F2FS_I_SB(inode)))
+		return -EOPNOTSUPP;
+
+	if (!f2fs_compressed_file(inode))
+		return -EINVAL;
+
+	if (f2fs_readonly(sbi->sb))
+		return -EROFS;
+
+	ret = mnt_want_write_file(filp);
+	if (ret)
+		return ret;
+
+	if (atomic_read(&F2FS_I(inode)->i_compr_blocks))
+		goto out;
+
+	inode_lock(inode);
+
+	if (!is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
+		ret = -EINVAL;
+		goto unlock_inode;
+	}
+
+	ret = f2fs_reserve_file(inode, &reserved_blocks);
+
+unlock_inode:
+	inode_unlock(inode);
+out:
+	mnt_drop_write_file(filp);
+
+	if (ret >= 0)
+		ret = put_user(reserved_blocks, (u64 __user *)arg);
+
+	return ret;
+}
+
 static int f2fs_secure_erase(struct block_device *bdev, struct inode *inode,
 		pgoff_t off, block_t block, block_t len, u32 flags)
 {
@@ -4412,8 +4425,11 @@ static ssize_t f2fs_write_checks(struct kiocb *iocb, struct iov_iter *from)
 	if (IS_IMMUTABLE(inode))
 		return -EPERM;
 
-	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED))
-		return -EPERM;
+	if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED)) {
+		err = f2fs_reserve_file(inode, NULL);
+		if (err < 0)
+			return err;
+	}
 
 	count = generic_write_checks(iocb, from);
 	if (count <= 0)
-- 
2.39.0