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	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>
		
	
			
		
			
				
	
	
		
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			145 lines
		
	
	
	
		
			3.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* Internal definitions for network filesystem support
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 *
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 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
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 * Written by David Howells (dhowells@redhat.com)
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 */
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#include <linux/netfs.h>
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#include <linux/fscache.h>
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#include <trace/events/netfs.h>
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#ifdef pr_fmt
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#undef pr_fmt
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#endif
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#define pr_fmt(fmt) "netfs: " fmt
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/*
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 * buffered_read.c
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 */
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void netfs_rreq_unlock_folios(struct netfs_io_request *rreq);
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/*
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 * io.c
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 */
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int netfs_begin_read(struct netfs_io_request *rreq, bool sync);
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/*
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 * main.c
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 */
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extern unsigned int netfs_debug;
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/*
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 * objects.c
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 */
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struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
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					     struct file *file,
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					     loff_t start, size_t len,
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					     enum netfs_io_origin origin);
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void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what);
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void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async);
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void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
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		       enum netfs_rreq_ref_trace what);
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struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq);
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static inline void netfs_see_request(struct netfs_io_request *rreq,
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				     enum netfs_rreq_ref_trace what)
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{
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	trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), what);
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}
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/*
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 * stats.c
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 */
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#ifdef CONFIG_NETFS_STATS
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extern atomic_t netfs_n_rh_readahead;
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extern atomic_t netfs_n_rh_readpage;
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extern atomic_t netfs_n_rh_rreq;
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extern atomic_t netfs_n_rh_sreq;
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extern atomic_t netfs_n_rh_download;
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extern atomic_t netfs_n_rh_download_done;
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extern atomic_t netfs_n_rh_download_failed;
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extern atomic_t netfs_n_rh_download_instead;
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extern atomic_t netfs_n_rh_read;
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extern atomic_t netfs_n_rh_read_done;
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extern atomic_t netfs_n_rh_read_failed;
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extern atomic_t netfs_n_rh_zero;
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extern atomic_t netfs_n_rh_short_read;
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extern atomic_t netfs_n_rh_write;
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extern atomic_t netfs_n_rh_write_begin;
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extern atomic_t netfs_n_rh_write_done;
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extern atomic_t netfs_n_rh_write_failed;
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extern atomic_t netfs_n_rh_write_zskip;
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static inline void netfs_stat(atomic_t *stat)
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{
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	atomic_inc(stat);
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}
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static inline void netfs_stat_d(atomic_t *stat)
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{
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	atomic_dec(stat);
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}
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#else
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#define netfs_stat(x) do {} while(0)
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#define netfs_stat_d(x) do {} while(0)
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#endif
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/*
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 * Miscellaneous functions.
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 */
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static inline bool netfs_is_cache_enabled(struct netfs_inode *ctx)
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{
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#if IS_ENABLED(CONFIG_FSCACHE)
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	struct fscache_cookie *cookie = ctx->cache;
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	return fscache_cookie_valid(cookie) && cookie->cache_priv &&
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		fscache_cookie_enabled(cookie);
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#else
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	return false;
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#endif
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}
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/*****************************************************************************/
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/*
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 * debug tracing
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 */
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#define dbgprintk(FMT, ...) \
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	printk("[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
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#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
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#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
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#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
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#ifdef __KDEBUG
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#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
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#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
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#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
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#elif defined(CONFIG_NETFS_DEBUG)
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#define _enter(FMT, ...)			\
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do {						\
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	if (netfs_debug)			\
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		kenter(FMT, ##__VA_ARGS__);	\
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} while (0)
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#define _leave(FMT, ...)			\
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do {						\
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	if (netfs_debug)			\
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		kleave(FMT, ##__VA_ARGS__);	\
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} while (0)
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#define _debug(FMT, ...)			\
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do {						\
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	if (netfs_debug)			\
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		kdebug(FMT, ##__VA_ARGS__);	\
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} while (0)
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#else
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#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
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#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
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#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
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#endif
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