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From:   Daeho Jeong <daeho43@gmail.com>
To:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com
Cc:     Daeho Jeong <daehojeong@google.com>
Subject: [PATCH 2/2] f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE
Date:   Tue, 17 Nov 2020 13:02:23 +0900
Message-Id: <20201117040223.858979-2-daeho43@gmail.com>
In-Reply-To: <20201117040223.858979-1-daeho43@gmail.com>
References: <20201117040223.858979-1-daeho43@gmail.com>
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From: Daeho Jeong <daehojeong@google.com>

Added two ioctl to decompress/compress explicitly the compression
enabled file in disable_auto_compr mount option.

Using these two ioctls, the users can make a control of compression
and decompression of their files.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
---
 fs/f2fs/f2fs.h |  10 ++-
 fs/f2fs/file.c | 182 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 191 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c473c78699bc..0dd3be63ac66 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -436,6 +436,8 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal,
 						struct f2fs_sectrim_range)
 #define F2FS_IOC_GET_COMPRESS_OPTION	_IOR(F2FS_IOCTL_MAGIC, 21,	\
 						struct f2fs_comp_option)
+#define F2FS_IOC_DECOMPRESS_FILE	_IO(F2FS_IOCTL_MAGIC, 23)
+#define F2FS_IOC_COMPRESS_FILE		_IO(F2FS_IOCTL_MAGIC, 24)
 
 /*
  * should be same as XFS_IOC_GOINGDOWN.
@@ -762,6 +764,8 @@ enum {
 	FI_VERITY_IN_PROGRESS,	/* building fs-verity Merkle tree */
 	FI_COMPRESSED_FILE,	/* indicate file's data can be compressed */
 	FI_MMAP_FILE,		/* indicate file was mmapped */
+	FI_FORCE_UNCOMPRESS,	/* indicate forcing to disable file compression */
+	FI_FORCE_COMPRESS,	/* indicate forcing file compression */
 	FI_MAX,			/* max flag, never be used */
 };
 
@@ -2841,7 +2845,11 @@ static inline int f2fs_compressed_file(struct inode *inode)
 
 static inline int f2fs_need_compress_write(struct inode *inode)
 {
-	if (test_opt(F2FS_I_SB(inode), DISABLE_AUTO_COMPR))
+	if (is_inode_flag_set(inode, FI_FORCE_UNCOMPRESS))
+		return 0;
+	else if (is_inode_flag_set(inode, FI_FORCE_COMPRESS))
+		return 1;
+	else if (test_opt(F2FS_I_SB(inode), DISABLE_AUTO_COMPR))
 		return 0;
 	return f2fs_compressed_file(inode);
 }
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index bd52df84219d..1e7ff96d7c6e 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3963,6 +3963,182 @@ static int f2fs_ioc_get_compress_option(struct file *filp, unsigned long arg)
 	return 0;
 }
 
+static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int len)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	struct address_space *mapping = inode->i_mapping;
+	struct page *page;
+	pgoff_t redirty_idx = page_idx;
+	int i, page_len = 0, ret = 0;
+
+	page_cache_readahead_unbounded(mapping, NULL, page_idx, len, 0);
+
+	for (i = 0; i < len; i++, page_idx++) {
+		page = read_cache_page(mapping, page_idx, NULL, NULL);
+		if (IS_ERR(page)) {
+			ret = PTR_ERR(page);
+			f2fs_warn(sbi, "%s: inode (%lu) : page_index (%lu) "
+				"couldn't be read (errno:%d).\n",
+				__func__, inode->i_ino, page_idx, ret);
+			break;
+		}
+		page_len++;
+	}
+
+	for (i = 0; i < page_len; i++, redirty_idx++) {
+		page = find_lock_page(mapping, redirty_idx);
+		if (!page) {
+			ret = -ENOENT;
+			f2fs_warn(sbi, "%s: inode (%lu) : page_index (%lu) "
+				"couldn't be found (errno:%d).\n",
+				__func__, inode->i_ino, redirty_idx, ret);
+		}
+		set_page_dirty(page);
+		f2fs_put_page(page, 1);
+		f2fs_put_page(page, 0);
+	}
+
+	return ret;
+}
+
+static int f2fs_ioc_decompress_file(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	pgoff_t page_idx = 0, last_idx;
+	int cluster_size = F2FS_I(inode)->i_cluster_size;
+	int count, ret;
+
+	if (!f2fs_sb_has_compression(sbi))
+		return -EOPNOTSUPP;
+
+	if (!(filp->f_mode & FMODE_WRITE))
+		return -EBADF;
+
+	if (!f2fs_compressed_file(inode))
+		return -EINVAL;
+
+	f2fs_balance_fs(F2FS_I_SB(inode), true);
+
+	file_start_write(filp);
+	inode_lock(inode);
+
+	if (f2fs_is_mmap_file(inode)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
+	if (ret)
+		goto out;
+
+	if (!F2FS_I(inode)->i_compr_blocks)
+		goto out;
+
+	set_inode_flag(inode, FI_FORCE_UNCOMPRESS);
+
+	last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
+
+	count = last_idx - page_idx;
+	while (count) {
+		int len = min(cluster_size, count);
+
+		ret = redirty_blocks(inode, page_idx, len);
+
+		if (ret < 0)
+			break;
+
+		page_idx += len;
+		count -= len;
+	}
+
+	if (!ret)
+		ret = filemap_write_and_wait_range(inode->i_mapping, 0,
+							LLONG_MAX);
+
+	clear_inode_flag(inode, FI_FORCE_UNCOMPRESS);
+
+	if (!ret) {
+		stat_sub_compr_blocks(inode, F2FS_I(inode)->i_compr_blocks);
+		F2FS_I(inode)->i_compr_blocks = 0;
+		f2fs_mark_inode_dirty_sync(inode, true);
+	} else {
+		f2fs_warn(sbi, "%s: The file might be partially decompressed "
+				"(errno=%d). Please delete the file.\n",
+				__func__, ret);
+	}
+out:
+	inode_unlock(inode);
+	file_end_write(filp);
+
+	return ret;
+}
+
+static int f2fs_ioc_compress_file(struct file *filp, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	pgoff_t page_idx = 0, last_idx;
+	int cluster_size = F2FS_I(inode)->i_cluster_size;
+	int count, ret;
+
+	if (!f2fs_sb_has_compression(sbi))
+		return -EOPNOTSUPP;
+
+	if (!(filp->f_mode & FMODE_WRITE))
+		return -EBADF;
+
+	if (!f2fs_compressed_file(inode))
+		return -EINVAL;
+
+	f2fs_balance_fs(F2FS_I_SB(inode), true);
+
+	file_start_write(filp);
+	inode_lock(inode);
+
+	if (f2fs_is_mmap_file(inode)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
+	if (ret)
+		goto out;
+
+	set_inode_flag(inode, FI_FORCE_COMPRESS);
+
+	last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
+
+	count = last_idx - page_idx;
+	while (count) {
+		int len = min(cluster_size, count);
+
+		ret = redirty_blocks(inode, page_idx, len);
+
+		if (ret < 0)
+			break;
+
+		page_idx += len;
+		count -= len;
+	}
+
+	if (!ret)
+		ret = filemap_write_and_wait_range(inode->i_mapping, 0,
+							LLONG_MAX);
+
+	clear_inode_flag(inode, FI_FORCE_COMPRESS);
+
+	if (ret)
+		f2fs_warn(sbi, "%s: The file might be partially compressed "
+				"(errno=%d). Please delete the file.\n",
+				__func__, ret);
+out:
+	inode_unlock(inode);
+	file_end_write(filp);
+
+	return ret;
+}
+
 long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(filp)))))
@@ -4053,6 +4229,10 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return f2fs_sec_trim_file(filp, arg);
 	case F2FS_IOC_GET_COMPRESS_OPTION:
 		return f2fs_ioc_get_compress_option(filp, arg);
+	case F2FS_IOC_DECOMPRESS_FILE:
+		return f2fs_ioc_decompress_file(filp, arg);
+	case F2FS_IOC_COMPRESS_FILE:
+		return f2fs_ioc_compress_file(filp, arg);
 	default:
 		return -ENOTTY;
 	}
@@ -4224,6 +4404,8 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case F2FS_IOC_RESERVE_COMPRESS_BLOCKS:
 	case F2FS_IOC_SEC_TRIM_FILE:
 	case F2FS_IOC_GET_COMPRESS_OPTION:
+	case F2FS_IOC_DECOMPRESS_FILE:
+	case F2FS_IOC_COMPRESS_FILE:
 		break;
 	default:
 		return -ENOIOCTLCMD;
-- 
2.29.2.299.gdc1121823c-goog