Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *  linux/fs/9p/vfs_addr.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * This file contians vfs address (mmap) ops for 9P2000.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/file.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/stat.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/inet.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/pagemap.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/idr.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include <linux/uio.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include <linux/bvec.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include <net/9p/9p.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include <net/9p/client.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #include "v9fs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include "v9fs_vfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) #include "cache.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #include "fid.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32)  * v9fs_fid_readpage - read an entire page in from 9P
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34)  * @fid: fid being read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35)  * @page: structure to page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) static int v9fs_fid_readpage(void *data, struct page *page)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	struct p9_fid *fid = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	struct inode *inode = page->mapping->host;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	struct iov_iter to;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	int retval, err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	p9_debug(P9_DEBUG_VFS, "\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	BUG_ON(!PageLocked(page));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	retval = v9fs_readpage_from_fscache(inode, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	if (retval == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 		return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	retval = p9_client_read(fid, page_offset(page), &to, &err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	if (err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 		v9fs_uncache_page(inode, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 		retval = err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		goto done;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	zero_user(page, retval, PAGE_SIZE - retval);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	flush_dcache_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	SetPageUptodate(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	v9fs_readpage_to_fscache(inode, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) done:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	unlock_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76)  * v9fs_vfs_readpage - read an entire page in from 9P
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78)  * @filp: file being read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79)  * @page: structure to page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) static int v9fs_vfs_readpage(struct file *filp, struct page *page)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	return v9fs_fid_readpage(filp->private_data, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89)  * v9fs_vfs_readpages - read a set of pages from 9P
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91)  * @filp: file being read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92)  * @mapping: the address space
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93)  * @pages: list of pages to read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94)  * @nr_pages: count of pages to read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 			     struct list_head *pages, unsigned nr_pages)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	int ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	inode = mapping->host;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	if (ret == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	ret = read_cache_pages(mapping, pages, v9fs_fid_readpage,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 			filp->private_data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	p9_debug(P9_DEBUG_VFS, "  = %d\n", ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)  * v9fs_release_page - release the private state associated with a page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)  * Returns 1 if the page can be released, false otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) static int v9fs_release_page(struct page *page, gfp_t gfp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	if (PagePrivate(page))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	return v9fs_fscache_release_page(page, gfp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)  * v9fs_invalidate_page - Invalidate a page completely or partially
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)  * @page: structure to page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134)  * @offset: offset in the page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) static void v9fs_invalidate_page(struct page *page, unsigned int offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 				 unsigned int length)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	 * If called with zero offset, we should release
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	 * the private state assocated with the page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	if (offset == 0 && length == PAGE_SIZE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		v9fs_fscache_invalidate_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) static int v9fs_vfs_writepage_locked(struct page *page)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	struct inode *inode = page->mapping->host;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	struct v9fs_inode *v9inode = V9FS_I(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	loff_t size = i_size_read(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	struct iov_iter from;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	struct bio_vec bvec;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	int err, len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	if (page->index == size >> PAGE_SHIFT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 		len = size & ~PAGE_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 		len = PAGE_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	bvec.bv_page = page;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	bvec.bv_offset = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	bvec.bv_len = len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	iov_iter_bvec(&from, WRITE, &bvec, 1, len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	/* We should have writeback_fid always set */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	BUG_ON(!v9inode->writeback_fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	set_page_writeback(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	end_page_writeback(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	int retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	p9_debug(P9_DEBUG_VFS, "page %p\n", page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	retval = v9fs_vfs_writepage_locked(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	if (retval < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 		if (retval == -EAGAIN) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 			redirty_page_for_writepage(wbc, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 			retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 			SetPageError(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 			mapping_set_error(page->mapping, retval);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	} else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 		retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	unlock_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201)  * v9fs_launder_page - Writeback a dirty page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202)  * Returns 0 on success.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) static int v9fs_launder_page(struct page *page)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	int retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	struct inode *inode = page->mapping->host;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	v9fs_fscache_wait_on_page_write(inode, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	if (clear_page_dirty_for_io(page)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 		retval = v9fs_vfs_writepage_locked(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 		if (retval)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 			return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220)  * v9fs_direct_IO - 9P address space operation for direct I/O
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)  * @iocb: target I/O control block
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223)  * The presence of v9fs_direct_IO() in the address space ops vector
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224)  * allowes open() O_DIRECT flags which would have failed otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226)  * In the non-cached mode, we shunt off direct read and write requests before
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227)  * the VFS gets them, so this method should never be called.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229)  * Direct IO is not 'yet' supported in the cached mode. Hence when
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230)  * this routine is called through generic_file_aio_read(), the read/write fails
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231)  * with an error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) static ssize_t
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 	struct file *file = iocb->ki_filp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 	loff_t pos = iocb->ki_pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 	ssize_t n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 	int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	if (iov_iter_rw(iter) == WRITE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 		n = p9_client_write(file->private_data, pos, iter, &err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 		if (n) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 			struct inode *inode = file_inode(file);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 			loff_t i_size = i_size_read(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 			if (pos + n > i_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 				inode_add_bytes(inode, pos + n - i_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 		n = p9_client_read(file->private_data, pos, iter, &err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 	return n ? n : err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 			    loff_t pos, unsigned len, unsigned flags,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 			    struct page **pagep, void **fsdata)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	int retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	struct page *page;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	struct v9fs_inode *v9inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	pgoff_t index = pos >> PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	struct inode *inode = mapping->host;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	v9inode = V9FS_I(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) start:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	page = grab_cache_page_write_begin(mapping, index, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 	if (!page) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		retval = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 	BUG_ON(!v9inode->writeback_fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	if (PageUptodate(page))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	if (len == PAGE_SIZE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 	put_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 	if (!retval)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 		goto start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 	*pagep = page;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 	return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) static int v9fs_write_end(struct file *filp, struct address_space *mapping,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 			  loff_t pos, unsigned len, unsigned copied,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 			  struct page *page, void *fsdata)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	loff_t last_pos = pos + copied;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 	struct inode *inode = page->mapping->host;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	if (!PageUptodate(page)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 		if (unlikely(copied < len)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 			copied = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 			goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 		} else if (len == PAGE_SIZE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 			SetPageUptodate(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 	 * No need to use i_size_read() here, the i_size
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 	 * cannot change under us because we hold the i_mutex.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	if (last_pos > inode->i_size) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 		inode_add_bytes(inode, last_pos - inode->i_size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 		i_size_write(inode, last_pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 	set_page_dirty(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 	unlock_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	put_page(page);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 	return copied;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) const struct address_space_operations v9fs_addr_operations = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 	.readpage = v9fs_vfs_readpage,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 	.readpages = v9fs_vfs_readpages,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 	.set_page_dirty = __set_page_dirty_nobuffers,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	.writepage = v9fs_vfs_writepage,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	.write_begin = v9fs_write_begin,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 	.write_end = v9fs_write_end,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 	.releasepage = v9fs_release_page,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 	.invalidatepage = v9fs_invalidate_page,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	.launder_page = v9fs_launder_page,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	.direct_IO = v9fs_direct_IO,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) };