f2fs: delete obsolete FI_DROP_CACHE

FI_DROP_CACHE was introduced in commit 1e84371f ("f2fs: change
atomic and volatile write policies") for volatile write feature,
after commit 7bc155fe ("f2fs: kill volatile write support"),
we won't support volatile write, let's delete related codes.
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -2892,9 +2892,6 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
 
 	zero_user_segment(page, offset, PAGE_SIZE);
 write:
-	if (f2fs_is_drop_cache(inode))
-		goto out;
-
 	/* Dentry/quota blocks are controlled by checkpoint */
 	if (S_ISDIR(inode->i_mode) || quota_inode) {
 		/*

fs/f2fs/f2fs.h

@@ -781,7 +781,6 @@ enum {
 	FI_UPDATE_WRITE,	/* inode has in-place-update data */
 	FI_NEED_IPU,		/* used for ipu per file */
 	FI_ATOMIC_FILE,		/* indicate atomic file */
-	FI_DROP_CACHE,		/* drop dirty page cache */
 	FI_DATA_EXIST,		/* indicate data exists */
 	FI_INLINE_DOTS,		/* indicate inline dot dentries */
 	FI_SKIP_WRITES,		/* should skip data page writeback */
@@ -3278,11 +3277,6 @@ static inline bool f2fs_is_cow_file(struct inode *inode)
 	return is_inode_flag_set(inode, FI_COW_FILE);
 }
 
-static inline bool f2fs_is_drop_cache(struct inode *inode)
-{
-	return is_inode_flag_set(inode, FI_DROP_CACHE);
-}
-
 static inline void *inline_data_addr(struct inode *inode, struct page *page)
 {
 	struct f2fs_inode *ri = F2FS_INODE(page);