f2fs: support volatile operations for transient data
This patch adds support for volatile writes which keep data pages in memory
until f2fs_evict_inode is called by iput.
For instance, we can use this feature for the sqlite database as follows.
While supporting atomic writes for main database file, we can keep its journal
data temporarily in the page cache by the following sequence.
1. open
-> ioctl(F2FS_IOC_START_VOLATILE_WRITE);
2. writes
: keep all the data in the page cache.
3. flush to the database file with atomic writes
a. ioctl(F2FS_IOC_START_ATOMIC_WRITE);
b. writes
c. ioctl(F2FS_IOC_COMMIT_ATOMIC_WRITE);
4. close
-> drop the cached data
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 07fda63..8171e80 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -198,6 +198,7 @@
#define F2FS_IOCTL_MAGIC 0xf5
#define F2FS_IOC_START_ATOMIC_WRITE _IO(F2FS_IOCTL_MAGIC, 1)
#define F2FS_IOC_COMMIT_ATOMIC_WRITE _IO(F2FS_IOCTL_MAGIC, 2)
+#define F2FS_IOC_START_VOLATILE_WRITE _IO(F2FS_IOCTL_MAGIC, 3)
#if defined(__KERNEL__) && defined(CONFIG_COMPAT)
/*
@@ -1060,6 +1061,7 @@
FI_UPDATE_WRITE, /* inode has in-place-update data */
FI_NEED_IPU, /* used for ipu per file */
FI_ATOMIC_FILE, /* indicate atomic file */
+ FI_VOLATILE_FILE, /* indicate volatile file */
};
static inline void set_inode_flag(struct f2fs_inode_info *fi, int flag)
@@ -1151,6 +1153,11 @@
return is_inode_flag_set(F2FS_I(inode), FI_ATOMIC_FILE);
}
+static inline bool f2fs_is_volatile_file(struct inode *inode)
+{
+ return is_inode_flag_set(F2FS_I(inode), FI_VOLATILE_FILE);
+}
+
static inline void *inline_data_addr(struct page *page)
{
struct f2fs_inode *ri = F2FS_INODE(page);