linux/fs/cifs/fscache.c
David Howells 874c8ca1e6 netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context
While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled.  This was causing the
following complaint[1] from gcc v12:

  In file included from include/linux/string.h:253,
                   from include/linux/ceph/ceph_debug.h:7,
                   from fs/ceph/inode.c:2:
  In function 'fortify_memset_chk',
      inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
      inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
  include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
    242 |                         __write_overflow_field(p_size_field, size);
        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode).  The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

  perl -p -i -e 's/vfs_inode/netfs.inode/'g \
        `git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
 - Fix a couple of missed name changes due to a disabled cifs option.
 - Rename nfs_i_context to nfs_inode
 - Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
   structs.

[ This also undoes commit 507160f46c ("netfs: gcc-12: temporarily
  disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c8 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-06-09 13:55:00 -07:00

254 lines
6.2 KiB
C

// SPDX-License-Identifier: LGPL-2.1
/*
* CIFS filesystem cache interface
*
* Copyright (c) 2010 Novell, Inc.
* Author(s): Suresh Jayaraman <sjayaraman@suse.de>
*
*/
#include "fscache.h"
#include "cifsglob.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifsproto.h"
static void cifs_fscache_fill_volume_coherency(
struct cifs_tcon *tcon,
struct cifs_fscache_volume_coherency_data *cd)
{
memset(cd, 0, sizeof(*cd));
cd->resource_id = cpu_to_le64(tcon->resource_id);
cd->vol_create_time = tcon->vol_create_time;
cd->vol_serial_number = cpu_to_le32(tcon->vol_serial_number);
}
int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
{
struct cifs_fscache_volume_coherency_data cd;
struct TCP_Server_Info *server = tcon->ses->server;
struct fscache_volume *vcookie;
const struct sockaddr *sa = (struct sockaddr *)&server->dstaddr;
size_t slen, i;
char *sharename;
char *key;
int ret = -ENOMEM;
tcon->fscache = NULL;
switch (sa->sa_family) {
case AF_INET:
case AF_INET6:
break;
default:
cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
return -EINVAL;
}
memset(&key, 0, sizeof(key));
sharename = extract_sharename(tcon->treeName);
if (IS_ERR(sharename)) {
cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
return -EINVAL;
}
slen = strlen(sharename);
for (i = 0; i < slen; i++)
if (sharename[i] == '/')
sharename[i] = ';';
key = kasprintf(GFP_KERNEL, "cifs,%pISpc,%s", sa, sharename);
if (!key)
goto out;
cifs_fscache_fill_volume_coherency(tcon, &cd);
vcookie = fscache_acquire_volume(key,
NULL, /* preferred_cache */
&cd, sizeof(cd));
cifs_dbg(FYI, "%s: (%s/0x%p)\n", __func__, key, vcookie);
if (IS_ERR(vcookie)) {
if (vcookie != ERR_PTR(-EBUSY)) {
ret = PTR_ERR(vcookie);
goto out_2;
}
pr_err("Cache volume key already in use (%s)\n", key);
vcookie = NULL;
}
tcon->fscache = vcookie;
ret = 0;
out_2:
kfree(key);
out:
kfree(sharename);
return ret;
}
void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
{
struct cifs_fscache_volume_coherency_data cd;
cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);
cifs_fscache_fill_volume_coherency(tcon, &cd);
fscache_relinquish_volume(tcon->fscache, &cd, false);
tcon->fscache = NULL;
}
void cifs_fscache_get_inode_cookie(struct inode *inode)
{
struct cifs_fscache_inode_coherency_data cd;
struct cifsInodeInfo *cifsi = CIFS_I(inode);
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);
cifsi->netfs.cache =
fscache_acquire_cookie(tcon->fscache, 0,
&cifsi->uniqueid, sizeof(cifsi->uniqueid),
&cd, sizeof(cd),
i_size_read(&cifsi->netfs.inode));
}
void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
{
if (update) {
struct cifs_fscache_inode_coherency_data cd;
loff_t i_size = i_size_read(inode);
cifs_fscache_fill_coherency(inode, &cd);
fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
} else {
fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
}
}
void cifs_fscache_release_inode_cookie(struct inode *inode)
{
struct cifsInodeInfo *cifsi = CIFS_I(inode);
struct fscache_cookie *cookie = cifs_inode_cookie(inode);
if (cookie) {
cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
fscache_relinquish_cookie(cookie, false);
cifsi->netfs.cache = NULL;
}
}
/*
* Fallback page reading interface.
*/
static int fscache_fallback_read_page(struct inode *inode, struct page *page)
{
struct netfs_cache_resources cres;
struct fscache_cookie *cookie = cifs_inode_cookie(inode);
struct iov_iter iter;
struct bio_vec bvec[1];
int ret;
memset(&cres, 0, sizeof(cres));
bvec[0].bv_page = page;
bvec[0].bv_offset = 0;
bvec[0].bv_len = PAGE_SIZE;
iov_iter_bvec(&iter, READ, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
ret = fscache_begin_read_operation(&cres, cookie);
if (ret < 0)
return ret;
ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
NULL, NULL);
fscache_end_operation(&cres);
return ret;
}
/*
* Fallback page writing interface.
*/
static int fscache_fallback_write_page(struct inode *inode, struct page *page,
bool no_space_allocated_yet)
{
struct netfs_cache_resources cres;
struct fscache_cookie *cookie = cifs_inode_cookie(inode);
struct iov_iter iter;
struct bio_vec bvec[1];
loff_t start = page_offset(page);
size_t len = PAGE_SIZE;
int ret;
memset(&cres, 0, sizeof(cres));
bvec[0].bv_page = page;
bvec[0].bv_offset = 0;
bvec[0].bv_len = PAGE_SIZE;
iov_iter_bvec(&iter, WRITE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
ret = fscache_begin_write_operation(&cres, cookie);
if (ret < 0)
return ret;
ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
no_space_allocated_yet);
if (ret == 0)
ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL);
fscache_end_operation(&cres);
return ret;
}
/*
* Retrieve a page from FS-Cache
*/
int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
{
int ret;
cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n",
__func__, cifs_inode_cookie(inode), page, inode);
ret = fscache_fallback_read_page(inode, page);
if (ret < 0)
return ret;
/* Read completed synchronously */
SetPageUptodate(page);
return 0;
}
void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
{
cifs_dbg(FYI, "%s: (fsc: %p, p: %p, i: %p)\n",
__func__, cifs_inode_cookie(inode), page, inode);
fscache_fallback_write_page(inode, page, true);
}
/*
* Query the cache occupancy.
*/
int __cifs_fscache_query_occupancy(struct inode *inode,
pgoff_t first, unsigned int nr_pages,
pgoff_t *_data_first,
unsigned int *_data_nr_pages)
{
struct netfs_cache_resources cres;
struct fscache_cookie *cookie = cifs_inode_cookie(inode);
loff_t start, data_start;
size_t len, data_len;
int ret;
ret = fscache_begin_read_operation(&cres, cookie);
if (ret < 0)
return ret;
start = first * PAGE_SIZE;
len = nr_pages * PAGE_SIZE;
ret = cres.ops->query_occupancy(&cres, start, len, PAGE_SIZE,
&data_start, &data_len);
if (ret == 0) {
*_data_first = data_start / PAGE_SIZE;
*_data_nr_pages = len / PAGE_SIZE;
}
fscache_end_operation(&cres);
return ret;
}