[PATCH 03/13] fs: Restore kiocb.ki_hint

[Bart Van Assche <bvanassche@acm.org>]

Restore support for passing write hint information from a filesystem to the
block layer. Write hint information can be set via fcntl(fd, F_SET_RW_HINT,
&hint). This patch reverts commit 41d36a9f3e53 ("fs: remove kiocb.ki_hint").

Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 fs/aio.c                    |  1 +
 fs/cachefiles/io.c          |  2 ++
 fs/f2fs/file.c              |  6 ++++++
 include/linux/fs.h          | 12 ++++++++++++
 include/trace/events/f2fs.h |  5 ++++-
 io_uring/rw.c               |  1 +
 6 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/fs/aio.c b/fs/aio.c
index a4c2a6bac72c..a09743049738 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1466,6 +1466,7 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
 	req->ki_flags = req->ki_filp->f_iocb_flags;
 	if (iocb->aio_flags & IOCB_FLAG_RESFD)
 		req->ki_flags |= IOCB_EVENTFD;
+	req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp));
 	if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
 		/*
 		 * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
index 009d23cd435b..ad2870748c15 100644
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -138,6 +138,7 @@ static int cachefiles_read(struct netfs_cache_resources *cres,
 	ki->iocb.ki_filp	= file;
 	ki->iocb.ki_pos		= start_pos + skipped;
 	ki->iocb.ki_flags	= IOCB_DIRECT;
+	ki->iocb.ki_hint	= ki_hint_validate(file_write_hint(file));
 	ki->iocb.ki_ioprio	= get_current_ioprio();
 	ki->skipped		= skipped;
 	ki->object		= object;
@@ -306,6 +307,7 @@ int __cachefiles_write(struct cachefiles_object *object,
 	ki->iocb.ki_filp	= file;
 	ki->iocb.ki_pos		= start_pos;
 	ki->iocb.ki_flags	= IOCB_DIRECT | IOCB_WRITE;
+	ki->iocb.ki_hint	= ki_hint_validate(file_write_hint(file));
 	ki->iocb.ki_ioprio	= get_current_ioprio();
 	ki->object		= object;
 	ki->start		= start_pos;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index ca5904129b16..9dc0e06c38ba 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4634,8 +4634,10 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from,
 	struct f2fs_inode_info *fi = F2FS_I(inode);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	const bool do_opu = f2fs_lfs_mode(sbi);
+	const int whint_mode = F2FS_OPTION(sbi).whint_mode;
 	const loff_t pos = iocb->ki_pos;
 	const ssize_t count = iov_iter_count(from);
+	const enum rw_hint hint = iocb->ki_hint;
 	unsigned int dio_flags;
 	struct iomap_dio *dio;
 	ssize_t ret;
@@ -4668,6 +4670,8 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from,
 		if (do_opu)
 			f2fs_down_read(&fi->i_gc_rwsem[READ]);
 	}
+	if (whint_mode == WHINT_MODE_OFF)
+		iocb->ki_hint = WRITE_LIFE_NOT_SET;
 
 	/*
 	 * We have to use __iomap_dio_rw() and iomap_dio_complete() instead of
@@ -4690,6 +4694,8 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from,
 		ret = iomap_dio_complete(dio);
 	}
 
+	if (whint_mode == WHINT_MODE_OFF)
+		iocb->ki_hint = hint;
 	if (do_opu)
 		f2fs_up_read(&fi->i_gc_rwsem[READ]);
 	f2fs_up_read(&fi->i_gc_rwsem[WRITE]);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ba2c5c90af6d..8ebed22dfc88 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -374,6 +374,7 @@ struct kiocb {
 	void (*ki_complete)(struct kiocb *iocb, long ret);
 	void			*private;
 	int			ki_flags;
+	u16			ki_hint;
 	u16			ki_ioprio; /* See linux/ioprio.h */
 	union {
 		/*
@@ -2143,11 +2144,21 @@ static inline enum rw_hint file_write_hint(struct file *file)
 	return file_inode(file)->i_write_hint;
 }
 
+static inline u16 ki_hint_validate(enum rw_hint hint)
+{
+	typeof(((struct kiocb *)0)->ki_hint) max_hint = -1;
+
+	if (hint <= max_hint)
+		return hint;
+	return 0;
+}
+
 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
 {
 	*kiocb = (struct kiocb) {
 		.ki_filp = filp,
 		.ki_flags = filp->f_iocb_flags,
+		.ki_hint = ki_hint_validate(file_write_hint(filp)),
 		.ki_ioprio = get_current_ioprio(),
 	};
 }
@@ -2158,6 +2169,7 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
 	*kiocb = (struct kiocb) {
 		.ki_filp = filp,
 		.ki_flags = kiocb_src->ki_flags,
+		.ki_hint = kiocb_src->ki_hint,
 		.ki_ioprio = kiocb_src->ki_ioprio,
 		.ki_pos = kiocb_src->ki_pos,
 	};
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 793f82cc1515..9247ad58034e 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -946,6 +946,7 @@ TRACE_EVENT(f2fs_direct_IO_enter,
 		__field(ino_t,	ino)
 		__field(loff_t,	ki_pos)
 		__field(int,	ki_flags)
+		__field(u16,    ki_hint)
 		__field(u16,	ki_ioprio)
 		__field(unsigned long,	len)
 		__field(int,	rw)
@@ -956,16 +957,18 @@ TRACE_EVENT(f2fs_direct_IO_enter,
 		__entry->ino		= inode->i_ino;
 		__entry->ki_pos		= iocb->ki_pos;
 		__entry->ki_flags	= iocb->ki_flags;
+		__entry->ki_hint	= iocb->ki_hint;
 		__entry->ki_ioprio	= iocb->ki_ioprio;
 		__entry->len		= len;
 		__entry->rw		= rw;
 	),
 
-	TP_printk("dev = (%d,%d), ino = %lu pos = %lld len = %lu ki_flags = %x ki_ioprio = %x rw = %d",
+	TP_printk("dev = (%d,%d), ino = %lu pos = %lld len = %lu ki_flags = %x ki_hint = %x ki_ioprio = %x rw = %d",
 		show_dev_ino(__entry),
 		__entry->ki_pos,
 		__entry->len,
 		__entry->ki_flags,
+		__entry->ki_hint,
 		__entry->ki_ioprio,
 		__entry->rw)
 );
diff --git a/io_uring/rw.c b/io_uring/rw.c
index c8c822fa7980..c41ae6654116 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -677,6 +677,7 @@ static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
 		req->flags |= io_file_get_flags(file);
 
 	kiocb->ki_flags = file->f_iocb_flags;
+	kiocb->ki_hint = file_inode(file)->i_write_hint;
 	ret = kiocb_set_rw_flags(kiocb, rw->flags);
 	if (unlikely(ret))
 		return ret;