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authorDavid Howells <dhowells@redhat.com>2022-06-09 23:46:04 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-06-09 23:55:00 +0300
commit874c8ca1e60b2c564a48f7e7acc40d328d5c8733 (patch)
treef56e0d0a842cc459f8a4a062c88dd54a869d82c5 /include/linux/netfs.h
parent3d9f55c57bc3659f986acc421eac431ff6edcc83 (diff)
downloadlinux-874c8ca1e60b2c564a48f7e7acc40d328d5c8733.tar.xz
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 507160f46c55 ("netfs: gcc-12: temporarily disable '-Wattribute-warning' for now") that is no longer needed ] Fixes: bc899ee1c898 ("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>
Diffstat (limited to 'include/linux/netfs.h')
-rw-r--r--include/linux/netfs.h41
1 files changed, 16 insertions, 25 deletions
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 77fa6a61706a..6dbb4c9ce50d 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -119,9 +119,10 @@ typedef void (*netfs_io_terminated_t)(void *priv, ssize_t transferred_or_error,
bool was_async);
/*
- * Per-inode description. This must be directly after the inode struct.
+ * Per-inode context. This wraps the VFS inode.
*/
-struct netfs_i_context {
+struct netfs_inode {
+ struct inode inode; /* The VFS inode */
const struct netfs_request_ops *ops;
#if IS_ENABLED(CONFIG_FSCACHE)
struct fscache_cookie *cache;
@@ -256,7 +257,7 @@ struct netfs_cache_ops {
* boundary as appropriate.
*/
enum netfs_io_source (*prepare_read)(struct netfs_io_subrequest *subreq,
- loff_t i_size);
+ loff_t i_size);
/* Prepare a write operation, working out what part of the write we can
* actually do.
@@ -288,45 +289,35 @@ extern void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
extern void netfs_stats_show(struct seq_file *);
/**
- * netfs_i_context - Get the netfs inode context from the inode
+ * netfs_inode - Get the netfs inode context from the inode
* @inode: The inode to query
*
* Get the netfs lib inode context from the network filesystem's inode. The
* context struct is expected to directly follow on from the VFS inode struct.
*/
-static inline struct netfs_i_context *netfs_i_context(struct inode *inode)
+static inline struct netfs_inode *netfs_inode(struct inode *inode)
{
- return (void *)inode + sizeof(*inode);
+ return container_of(inode, struct netfs_inode, inode);
}
/**
- * netfs_inode - Get the netfs inode from the inode context
- * @ctx: The context to query
- *
- * Get the netfs inode from the netfs library's inode context. The VFS inode
- * is expected to directly precede the context struct.
- */
-static inline struct inode *netfs_inode(struct netfs_i_context *ctx)
-{
- return (void *)ctx - sizeof(struct inode);
-}
-
-/**
- * netfs_i_context_init - Initialise a netfs lib context
+ * netfs_inode_init - Initialise a netfslib inode context
* @inode: The inode with which the context is associated
* @ops: The netfs's operations list
*
* Initialise the netfs library context struct. This is expected to follow on
* directly from the VFS inode struct.
*/
-static inline void netfs_i_context_init(struct inode *inode,
- const struct netfs_request_ops *ops)
+static inline void netfs_inode_init(struct inode *inode,
+ const struct netfs_request_ops *ops)
{
- struct netfs_i_context *ctx = netfs_i_context(inode);
+ struct netfs_inode *ctx = netfs_inode(inode);
- memset(ctx, 0, sizeof(*ctx));
ctx->ops = ops;
ctx->remote_i_size = i_size_read(inode);
+#if IS_ENABLED(CONFIG_FSCACHE)
+ ctx->cache = NULL;
+#endif
}
/**
@@ -338,7 +329,7 @@ static inline void netfs_i_context_init(struct inode *inode,
*/
static inline void netfs_resize_file(struct inode *inode, loff_t new_i_size)
{
- struct netfs_i_context *ctx = netfs_i_context(inode);
+ struct netfs_inode *ctx = netfs_inode(inode);
ctx->remote_i_size = new_i_size;
}
@@ -352,7 +343,7 @@ static inline void netfs_resize_file(struct inode *inode, loff_t new_i_size)
static inline struct fscache_cookie *netfs_i_cookie(struct inode *inode)
{
#if IS_ENABLED(CONFIG_FSCACHE)
- struct netfs_i_context *ctx = netfs_i_context(inode);
+ struct netfs_inode *ctx = netfs_inode(inode);
return ctx->cache;
#else
return NULL;