f2fs: add compress_mode mount option

We will add a new "compress_mode" mount option to control file
compression mode. This supports "fs" and "user". In "fs" mode (default),
f2fs does automatic compression on the compression enabled files.
In "user" mode, f2fs disables the automaic compression and gives the
user discretion of choosing the target file and the timing. It means
the user can do manual compression/decompression on the compression
enabled files using ioctls.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4417f791dbc6..7c02b6d8465c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -148,6 +148,7 @@ struct f2fs_mount_info {
 	unsigned char compress_log_size;	/* cluster log size */
 	bool compress_chksum;			/* compressed data chksum */
 	unsigned char compress_ext_cnt;		/* extension count */
+	int compress_mode;			/* compression mode */
 	unsigned char extensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN];	/* extensions */
 };
 
@@ -677,6 +678,7 @@ enum {
 	FI_COMPRESSED_FILE,	/* indicate file's data can be compressed */
 	FI_COMPRESS_CORRUPT,	/* indicate compressed cluster is corrupted */
 	FI_MMAP_FILE,		/* indicate file was mmapped */
+	FI_ENABLE_COMPRESS,	/* enable compression in "user" compression mode */
 	FI_MAX,			/* max flag, never be used */
 };
 
@@ -1244,6 +1246,18 @@ enum fsync_mode {
 	FSYNC_MODE_NOBARRIER,	/* fsync behaves nobarrier based on posix */
 };
 
+enum {
+	COMPR_MODE_FS,		/*
+				 * automatically compress compression
+				 * enabled files
+				 */
+	COMPR_MODE_USER,	/*
+				 * automatical compression is disabled.
+				 * user can control the file compression
+				 * using ioctls
+				 */
+};
+
 /*
  * this value is set in page as a private data which indicate that
  * the page is atomically written, and it is in inmem_pages list.
@@ -2759,6 +2773,22 @@ static inline int f2fs_compressed_file(struct inode *inode)
 		is_inode_flag_set(inode, FI_COMPRESSED_FILE);
 }
 
+static inline bool f2fs_need_compress_data(struct inode *inode)
+{
+	int compress_mode = F2FS_OPTION(F2FS_I_SB(inode)).compress_mode;
+
+	if (!f2fs_compressed_file(inode))
+		return false;
+
+	if (compress_mode == COMPR_MODE_FS)
+		return true;
+	else if (compress_mode == COMPR_MODE_USER &&
+			is_inode_flag_set(inode, FI_ENABLE_COMPRESS))
+		return true;
+
+	return false;
+}
+
 static inline unsigned int addrs_per_inode(struct inode *inode)
 {
 	unsigned int addrs = CUR_ADDRS_PER_INODE(inode) -