fs: introduce IOCB_HAS_METADATA for metadata

Introduce an IOCB_HAS_METADATA flag for the kiocb struct, for handling
requests containing meta payload.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20241128112240.8867-6-anuj20.g@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Anuj Gupta

include/linux/fs.h

@@ -348,6 +348,7 @@ struct readahead_control;
 #define IOCB_DIO_CALLER_COMP	(1 << 22)
 /* kiocb is a read or write operation submitted by fs/aio.c. */
 #define IOCB_AIO_RW		(1 << 23)
+#define IOCB_HAS_METADATA	(1 << 24)
 
 /* for use in trace events */
 #define TRACE_IOCB_STRINGS \