// SPDX-License-Identifier: GPL-2.0/* *  linux/fs/ext2/file.c * * Copyright (C) 1992, 1993, 1994, 1995 * Remy Card (card@masi.ibp.fr) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * *  from * *  linux/fs/minix/file.c * *  Copyright (C) 1991, 1992  Linus Torvalds * *  ext2 fs regular file handling primitives * *  64-bit file support on 64-bit platforms by Jakub Jelinek * 	(jj@sunsite.ms.mff.cuni.cz) */ #include <linux/time.h>#include <linux/pagemap.h>#include <linux/filelock.h>#include <linux/quotaops.h>#include <linux/iomap.h>#include <linux/uio.h>#include <linux/buffer_head.h>#include "ext2.h"#include "xattr.h"#include "acl.h"#include "trace.h"  /* * Called when filp is released. This happens when all file descriptors * for a single struct file are closed. Note that different open() calls * for the same file yield different struct file structures. */static int ext2_release_file (struct inode * inode, struct file * filp){	if (filp->f_mode & FMODE_WRITE) {		mutex_lock(&EXT2_I(inode)->truncate_mutex);		ext2_discard_reservation(inode);		mutex_unlock(&EXT2_I(inode)->truncate_mutex);	}	return 0;} static ssize_t ext2_dio_read_iter(struct kiocb *iocb, struct iov_iter *to){	struct file *file = iocb->ki_filp;	struct inode *inode = file->f_mapping->host;	ssize_t ret; 	trace_ext2_dio_read_begin(iocb, to, 0);	inode_lock_shared(inode);	ret = iomap_dio_rw(iocb, to, &ext2_iomap_ops, NULL, 0, NULL, 0);	inode_unlock_shared(inode);	trace_ext2_dio_read_end(iocb, to, ret); 	return ret;} static int ext2_dio_write_end_io(struct kiocb *iocb, ssize_t size,				 int error, unsigned int flags){	loff_t pos = iocb->ki_pos;	struct inode *inode = file_inode(iocb->ki_filp); 	if (error)		goto out; 	/*	 * If we are extending the file, we have to update i_size here before	 * page cache gets invalidated in iomap_dio_rw(). This prevents racing	 * buffered reads from zeroing out too much from page cache pages.	 * Note that all extending writes always happens synchronously with	 * inode lock held by ext2_dio_write_iter(). So it is safe to update	 * inode size here for extending file writes.	 */	pos += size;	if (pos > i_size_read(inode)) {		i_size_write(inode, pos);		mark_inode_dirty(inode);	}out:	trace_ext2_dio_write_endio(iocb, size, error);	return error;} static const struct iomap_dio_ops ext2_dio_write_ops = {	.end_io = ext2_dio_write_end_io,}; static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from){	struct file *file = iocb->ki_filp;	struct inode *inode = file->f_mapping->host;	ssize_t ret;	unsigned int flags = 0;	unsigned long blocksize = inode->i_sb->s_blocksize;	loff_t offset = iocb->ki_pos;	loff_t count = iov_iter_count(from);	ssize_t status = 0; 	trace_ext2_dio_write_begin(iocb, from, 0);	inode_lock(inode);	ret = generic_write_checks(iocb, from);	if (ret <= 0)		goto out_unlock; 	ret = kiocb_modified(iocb);	if (ret)		goto out_unlock; 	/* use IOMAP_DIO_FORCE_WAIT for unaligned or extending writes */	if (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode) ||	   (!IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(from), blocksize)))		flags |= IOMAP_DIO_FORCE_WAIT; 	ret = iomap_dio_rw(iocb, from, &ext2_iomap_ops, &ext2_dio_write_ops,			   flags, NULL, 0); 	/* ENOTBLK is magic return value for fallback to buffered-io */	if (ret == -ENOTBLK)		ret = 0; 	if (ret < 0 && ret != -EIOCBQUEUED)		ext2_write_failed(inode->i_mapping, offset + count); 	/* handle case for partial write and for fallback to buffered write */	if (ret >= 0 && iov_iter_count(from)) {		loff_t pos, endbyte;		int ret2; 		iocb->ki_flags &= ~IOCB_DIRECT;		pos = iocb->ki_pos;		status = generic_perform_write(iocb, from);		if (unlikely(status < 0)) {			ret = status;			goto out_unlock;		} 		ret += status;		endbyte = pos + status - 1;		ret2 = filemap_write_and_wait_range(inode->i_mapping, pos,						    endbyte);		if (!ret2) {			invalidate_mapping_pages(inode->i_mapping,						 pos >> PAGE_SHIFT,						 endbyte >> PAGE_SHIFT);			if (ret > 0)				ret = generic_write_sync(iocb, ret);		} else {			ret = ret2;		}	} out_unlock:	inode_unlock(inode);	if (status)		trace_ext2_dio_write_buff_end(iocb, from, status);	trace_ext2_dio_write_end(iocb, from, ret);	return ret;} static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to){	if (iocb->ki_flags & IOCB_DIRECT)		return ext2_dio_read_iter(iocb, to); 	return generic_file_read_iter(iocb, to);} static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from){	if (iocb->ki_flags & IOCB_DIRECT)		return ext2_dio_write_iter(iocb, from); 	return generic_file_write_iter(iocb, from);} static int ext2_file_open(struct inode *inode, struct file *filp){	filp->f_mode |= FMODE_CAN_ODIRECT;	return dquot_file_open(inode, filp);} const struct file_operations ext2_file_operations = {	.llseek		= generic_file_llseek,	.read_iter	= ext2_file_read_iter,	.write_iter	= ext2_file_write_iter,	.unlocked_ioctl = ext2_ioctl,#ifdef CONFIG_COMPAT	.compat_ioctl	= ext2_compat_ioctl,#endif	.mmap_prepare	= generic_file_mmap_prepare,	.open		= ext2_file_open,	.release	= ext2_release_file,	.fsync		= simple_fsync,	.get_unmapped_area = thp_get_unmapped_area,	.splice_read	= filemap_splice_read,	.splice_write	= iter_file_splice_write,	.setlease	= generic_setlease,}; const struct inode_operations ext2_file_inode_operations = {	.listxattr	= ext2_listxattr,	.getattr	= ext2_getattr,	.setattr	= ext2_setattr,	.get_inode_acl	= ext2_get_acl,	.set_acl	= ext2_set_acl,	.fiemap		= ext2_fiemap,	.fileattr_get	= ext2_fileattr_get,	.fileattr_set	= ext2_fileattr_set,};