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https://github.com/edk2-porting/linux-next.git
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de4eda9de2
READ/WRITE proved to be actively confusing - the meanings are "data destination, as used with read(2)" and "data source, as used with write(2)", but people keep interpreting those as "we read data from it" and "we write data to it", i.e. exactly the wrong way. Call them ITER_DEST and ITER_SOURCE - at least that is harder to misinterpret... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
254 lines
6.2 KiB
C
254 lines
6.2 KiB
C
// SPDX-License-Identifier: LGPL-2.1
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/*
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* CIFS filesystem cache interface
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*
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* Copyright (c) 2010 Novell, Inc.
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* Author(s): Suresh Jayaraman <sjayaraman@suse.de>
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*
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*/
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#include "fscache.h"
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#include "cifsglob.h"
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#include "cifs_debug.h"
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#include "cifs_fs_sb.h"
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#include "cifsproto.h"
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static void cifs_fscache_fill_volume_coherency(
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struct cifs_tcon *tcon,
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struct cifs_fscache_volume_coherency_data *cd)
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{
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memset(cd, 0, sizeof(*cd));
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cd->resource_id = cpu_to_le64(tcon->resource_id);
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cd->vol_create_time = tcon->vol_create_time;
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cd->vol_serial_number = cpu_to_le32(tcon->vol_serial_number);
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}
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int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
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{
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struct cifs_fscache_volume_coherency_data cd;
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struct TCP_Server_Info *server = tcon->ses->server;
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struct fscache_volume *vcookie;
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const struct sockaddr *sa = (struct sockaddr *)&server->dstaddr;
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size_t slen, i;
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char *sharename;
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char *key;
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int ret = -ENOMEM;
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tcon->fscache = NULL;
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switch (sa->sa_family) {
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case AF_INET:
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case AF_INET6:
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break;
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default:
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cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
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return -EINVAL;
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}
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memset(&key, 0, sizeof(key));
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sharename = extract_sharename(tcon->tree_name);
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if (IS_ERR(sharename)) {
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cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
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return -EINVAL;
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}
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slen = strlen(sharename);
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for (i = 0; i < slen; i++)
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if (sharename[i] == '/')
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sharename[i] = ';';
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key = kasprintf(GFP_KERNEL, "cifs,%pISpc,%s", sa, sharename);
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if (!key)
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goto out;
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cifs_fscache_fill_volume_coherency(tcon, &cd);
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vcookie = fscache_acquire_volume(key,
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NULL, /* preferred_cache */
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&cd, sizeof(cd));
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cifs_dbg(FYI, "%s: (%s/0x%p)\n", __func__, key, vcookie);
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if (IS_ERR(vcookie)) {
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if (vcookie != ERR_PTR(-EBUSY)) {
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ret = PTR_ERR(vcookie);
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goto out_2;
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}
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pr_err("Cache volume key already in use (%s)\n", key);
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vcookie = NULL;
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}
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tcon->fscache = vcookie;
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ret = 0;
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out_2:
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kfree(key);
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out:
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kfree(sharename);
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return ret;
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}
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void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
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{
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struct cifs_fscache_volume_coherency_data cd;
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cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);
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cifs_fscache_fill_volume_coherency(tcon, &cd);
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fscache_relinquish_volume(tcon->fscache, &cd, false);
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tcon->fscache = NULL;
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}
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void cifs_fscache_get_inode_cookie(struct inode *inode)
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{
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struct cifs_fscache_inode_coherency_data cd;
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struct cifsInodeInfo *cifsi = CIFS_I(inode);
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struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
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struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
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cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);
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cifsi->netfs.cache =
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fscache_acquire_cookie(tcon->fscache, 0,
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&cifsi->uniqueid, sizeof(cifsi->uniqueid),
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&cd, sizeof(cd),
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i_size_read(&cifsi->netfs.inode));
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}
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void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
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{
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if (update) {
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struct cifs_fscache_inode_coherency_data cd;
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loff_t i_size = i_size_read(inode);
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cifs_fscache_fill_coherency(inode, &cd);
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fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
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} else {
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fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
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}
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}
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void cifs_fscache_release_inode_cookie(struct inode *inode)
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{
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struct cifsInodeInfo *cifsi = CIFS_I(inode);
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struct fscache_cookie *cookie = cifs_inode_cookie(inode);
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if (cookie) {
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cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
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fscache_relinquish_cookie(cookie, false);
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cifsi->netfs.cache = NULL;
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}
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}
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/*
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* Fallback page reading interface.
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*/
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static int fscache_fallback_read_page(struct inode *inode, struct page *page)
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{
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struct netfs_cache_resources cres;
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struct fscache_cookie *cookie = cifs_inode_cookie(inode);
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struct iov_iter iter;
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struct bio_vec bvec[1];
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int ret;
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memset(&cres, 0, sizeof(cres));
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bvec[0].bv_page = page;
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bvec[0].bv_offset = 0;
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bvec[0].bv_len = PAGE_SIZE;
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iov_iter_bvec(&iter, ITER_DEST, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
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ret = fscache_begin_read_operation(&cres, cookie);
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if (ret < 0)
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return ret;
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ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
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NULL, NULL);
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fscache_end_operation(&cres);
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return ret;
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}
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/*
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* Fallback page writing interface.
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*/
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static int fscache_fallback_write_page(struct inode *inode, struct page *page,
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bool no_space_allocated_yet)
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{
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struct netfs_cache_resources cres;
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struct fscache_cookie *cookie = cifs_inode_cookie(inode);
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struct iov_iter iter;
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struct bio_vec bvec[1];
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loff_t start = page_offset(page);
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size_t len = PAGE_SIZE;
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int ret;
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memset(&cres, 0, sizeof(cres));
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bvec[0].bv_page = page;
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bvec[0].bv_offset = 0;
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bvec[0].bv_len = PAGE_SIZE;
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iov_iter_bvec(&iter, ITER_SOURCE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
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ret = fscache_begin_write_operation(&cres, cookie);
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if (ret < 0)
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return ret;
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ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
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no_space_allocated_yet);
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if (ret == 0)
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ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL);
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fscache_end_operation(&cres);
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return ret;
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}
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/*
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* Retrieve a page from FS-Cache
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*/
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int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
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{
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int ret;
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cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n",
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__func__, cifs_inode_cookie(inode), page, inode);
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ret = fscache_fallback_read_page(inode, page);
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if (ret < 0)
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return ret;
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/* Read completed synchronously */
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SetPageUptodate(page);
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return 0;
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}
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void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
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{
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cifs_dbg(FYI, "%s: (fsc: %p, p: %p, i: %p)\n",
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__func__, cifs_inode_cookie(inode), page, inode);
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fscache_fallback_write_page(inode, page, true);
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}
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/*
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* Query the cache occupancy.
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*/
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int __cifs_fscache_query_occupancy(struct inode *inode,
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pgoff_t first, unsigned int nr_pages,
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pgoff_t *_data_first,
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unsigned int *_data_nr_pages)
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{
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struct netfs_cache_resources cres;
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struct fscache_cookie *cookie = cifs_inode_cookie(inode);
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loff_t start, data_start;
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size_t len, data_len;
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int ret;
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ret = fscache_begin_read_operation(&cres, cookie);
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if (ret < 0)
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return ret;
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start = first * PAGE_SIZE;
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len = nr_pages * PAGE_SIZE;
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ret = cres.ops->query_occupancy(&cres, start, len, PAGE_SIZE,
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&data_start, &data_len);
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if (ret == 0) {
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*_data_first = data_start / PAGE_SIZE;
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*_data_nr_pages = len / PAGE_SIZE;
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}
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fscache_end_operation(&cres);
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return ret;
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}
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