[PATCH 00/14] server side user xattr support (RFC 8276)

[PATCH 00/14] server side user xattr support (RFC 8276)

[Frank van der Linden]

This patchset implements the server side for NFS user extended attributes,
as defined in RFC8726.

This was originally posted as an RFC in:

https://patchwork.kernel.org/cover/11143565/

Patch 1 is shared with the client side patch, posted
separately.

Most comments in there still apply, except that:

1. As per the discussion, user extended attributes are enabled if
   the client and server support them (e.g. they support 4.2 and
   advertise the user extended attribute FATTR). There are no longer
   options to switch them off on either the client or the server.
2. The code is no longer conditioned on a config option.
3. The number of patches has been reduced somewhat by merging
   smaller, related ones.

This has been tested as follows:

* Linux client and server:
	* Test all corner cases (XATTR_SIZE_*)
	* Test all failure cases (no xattr, setxattr with different or
	  invalid flags, etc).
	* Verify the content of xattrs across several operations.
	* Use KASAN and KMEMLEAK for a longer mix of testruns to verify
	  that there were no leaks (after unmounting the filesystem).

* Tested against the FreeBSD-current implementation as well, which works
  (after I fixed 2 bugs in that implementation, which I'm sending out to
  them too).

* Not tested: RDMA (I couldn't get a setup going).

Frank van der Linden (14):
  nfs,nfsd: NFSv4.2 extended attribute protocol definitions
  xattr: modify vfs_{set,remove}xattr for NFS server use
  nfsd: split off the write decode code in to a separate function
  nfsd: make sure the nfsd4_ops array has the right size
  nfsd: add defines for NFSv4.2 extended attribute support
  nfsd: define xattr functions to call in to their vfs counterparts
  nfsd: take xattr bits in to account for permission checks
  nfsd: add structure definitions for xattr requests / responses
  nfsd: use kvmalloc in svcxdr_tmpalloc
  nfsd: implement the xattr procedure functions.
  nfsd: add user xattr RPC XDR encoding/decoding logic
  nfsd: add xattr operations to ops array
  xattr: add a function to check if a namespace is supported
  nfsd: add fattr support for user extended attributes

 fs/nfsd/nfs4proc.c        | 141 +++++++++++-
 fs/nfsd/nfs4xdr.c         | 535 +++++++++++++++++++++++++++++++++++++++++++---
 fs/nfsd/nfsd.h            |   5 +-
 fs/nfsd/vfs.c             | 142 ++++++++++++
 fs/nfsd/vfs.h             |  10 +
 fs/nfsd/xdr4.h            |  31 +++
 fs/xattr.c                |  90 +++++++-
 include/linux/nfs4.h      |  22 +-
 include/linux/xattr.h     |   4 +
 include/uapi/linux/nfs4.h |   3 +
 10 files changed, 940 insertions(+), 43 deletions(-)

-- 
2.16.6

[PATCH 01/14] nfs,nfsd: NFSv4.2 extended attribute protocol definitions

[Frank van der Linden]

Add definitions for the new operations, errors and flags as defined
in RFC 8276 (File System Extended Attributes in NFSv4).

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 include/linux/nfs4.h      | 20 ++++++++++++++++++++
 include/uapi/linux/nfs4.h |  3 +++
 2 files changed, 23 insertions(+)

diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 82d8fb422092..350aeda0c48c 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -150,6 +150,12 @@ enum nfs_opnum4 {
 	OP_WRITE_SAME = 70,
 	OP_CLONE = 71,
 
+	/* xattr support (RFC8726) */
+	OP_GETXATTR                = 72,
+	OP_SETXATTR                = 73,
+	OP_LISTXATTRS              = 74,
+	OP_REMOVEXATTR             = 75,
+
 	OP_ILLEGAL = 10044,
 };
 
@@ -280,6 +286,10 @@ enum nfsstat4 {
 	NFS4ERR_WRONG_LFS = 10092,
 	NFS4ERR_BADLABEL = 10093,
 	NFS4ERR_OFFLOAD_NO_REQS = 10094,
+
+	/* xattr (RFC8276) */
+	NFS4ERR_NOXATTR        = 10095,
+	NFS4ERR_XATTR2BIG      = 10096,
 };
 
 static inline bool seqid_mutating_err(u32 err)
@@ -452,6 +462,7 @@ enum change_attr_type4 {
 #define FATTR4_WORD2_CHANGE_ATTR_TYPE	(1UL << 15)
 #define FATTR4_WORD2_SECURITY_LABEL     (1UL << 16)
 #define FATTR4_WORD2_MODE_UMASK		(1UL << 17)
+#define FATTR4_WORD2_XATTR_SUPPORT	(1UL << 18)
 
 /* MDS threshold bitmap bits */
 #define THRESHOLD_RD                    (1UL << 0)
@@ -700,4 +711,13 @@ struct nl4_server {
 		struct nfs42_netaddr	nl4_addr; /* NL4_NETADDR */
 	} u;
 };
+
+/*
+ * Options for setxattr. These match the flags for setxattr(2).
+ */
+enum nfs4_setxattr_options {
+	SETXATTR4_EITHER	= 0,
+	SETXATTR4_CREATE	= 1,
+	SETXATTR4_REPLACE	= 2,
+};
 #endif
diff --git a/include/uapi/linux/nfs4.h b/include/uapi/linux/nfs4.h
index 8572930cf5b0..bf197e99b98f 100644
--- a/include/uapi/linux/nfs4.h
+++ b/include/uapi/linux/nfs4.h
@@ -33,6 +33,9 @@
 #define NFS4_ACCESS_EXTEND      0x0008
 #define NFS4_ACCESS_DELETE      0x0010
 #define NFS4_ACCESS_EXECUTE     0x0020
+#define NFS4_ACCESS_XAREAD      0x0040
+#define NFS4_ACCESS_XAWRITE     0x0080
+#define NFS4_ACCESS_XALIST      0x0100
 
 #define NFS4_FH_PERSISTENT		0x0000
 #define NFS4_FH_NOEXPIRE_WITH_OPEN	0x0001
-- 
2.16.6

[PATCH 02/14] xattr: modify vfs_{set,remove}xattr for NFS server use

[Frank van der Linden]

To be called from the upcoming NFS server xattr code, the vfs_removexattr
and vfs_setxattr need some modifications.

First, they need to grow a _locked variant, since the NFS server code
will call this with i_rwsem held. It needs to do that in fh_lock to be
able to atomically provide the before and after change attributes.

Second, RFC 8276 (NFSv4 extended attribute support) specifies that
delegations should be recalled (8.4.2.4, 8.4.4.4) when a SETXATTR
or REMOVEXATTR operation is performed. So, like with other fs
operations, try to break the delegation. The _locked version of
these operations will not wait for the delegation to be successfully
broken, instead returning an error if it wasn't, so that the NFS
server code can return NFS4ERR_DELAY to the client (similar to
what e.g. vfs_link does).

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/xattr.c            | 63 +++++++++++++++++++++++++++++++++++++++++++++------
 include/linux/xattr.h |  2 ++
 2 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 90dd78f0eb27..58013bcbc333 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -204,10 +204,10 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
 	return error;
 }
 
-
 int
-vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
-		size_t size, int flags)
+__vfs_setxattr_locked(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags,
+		struct inode **delegated_inode)
 {
 	struct inode *inode = dentry->d_inode;
 	int error;
@@ -216,15 +216,40 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 	if (error)
 		return error;
 
-	inode_lock(inode);
 	error = security_inode_setxattr(dentry, name, value, size, flags);
 	if (error)
 		goto out;
 
+	error = try_break_deleg(inode, delegated_inode);
+	if (error)
+		goto out;
+
 	error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
 
 out:
+	return error;
+}
+EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
+
+int
+vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+		size_t size, int flags)
+{
+	struct inode *inode = dentry->d_inode;
+	struct inode *delegated_inode = NULL;
+	int error;
+
+retry_deleg:
+	inode_lock(inode);
+	error = __vfs_setxattr_locked(dentry, name, value, size, flags,
+	    &delegated_inode);
 	inode_unlock(inode);
+
+	if (delegated_inode) {
+		error = break_deleg_wait(&delegated_inode);
+		if (!error)
+			goto retry_deleg;
+	}
 	return error;
 }
 EXPORT_SYMBOL_GPL(vfs_setxattr);
@@ -379,7 +404,8 @@ __vfs_removexattr(struct dentry *dentry, const char *name)
 EXPORT_SYMBOL(__vfs_removexattr);
 
 int
-vfs_removexattr(struct dentry *dentry, const char *name)
+__vfs_removexattr_locked(struct dentry *dentry, const char *name,
+		struct inode **delegated_inode)
 {
 	struct inode *inode = dentry->d_inode;
 	int error;
@@ -388,11 +414,14 @@ vfs_removexattr(struct dentry *dentry, const char *name)
 	if (error)
 		return error;
 
-	inode_lock(inode);
 	error = security_inode_removexattr(dentry, name);
 	if (error)
 		goto out;
 
+	error = try_break_deleg(inode, delegated_inode);
+	if (error)
+		goto out;
+
 	error = __vfs_removexattr(dentry, name);
 
 	if (!error) {
@@ -401,12 +430,32 @@ vfs_removexattr(struct dentry *dentry, const char *name)
 	}
 
 out:
+	return error;
+}
+EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
+
+int
+vfs_removexattr(struct dentry *dentry, const char *name)
+{
+	struct inode *inode = dentry->d_inode;
+	struct inode *delegated_inode = NULL;
+	int error;
+
+retry_deleg:
+	inode_lock(inode);
+	error = __vfs_removexattr_locked(dentry, name, &delegated_inode);
 	inode_unlock(inode);
+
+	if (delegated_inode) {
+		error = break_deleg_wait(&delegated_inode);
+		if (!error)
+			goto retry_deleg;
+	}
+
 	return error;
 }
 EXPORT_SYMBOL_GPL(vfs_removexattr);
 
-
 /*
  * Extended attribute SET operations
  */
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index 6dad031be3c2..3a71ad716da5 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -51,8 +51,10 @@ ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
 int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
+int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
 int __vfs_removexattr(struct dentry *, const char *);
+int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **);
 int vfs_removexattr(struct dentry *, const char *);
 
 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
-- 
2.16.6

Re: [PATCH 02/14] xattr: modify vfs_{set,remove}xattr for NFS server use

[Chuck Lever]

> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> To be called from the upcoming NFS server xattr code, the vfs_removexattr
> and vfs_setxattr need some modifications.
> 
> First, they need to grow a _locked variant, since the NFS server code
> will call this with i_rwsem held. It needs to do that in fh_lock to be
> able to atomically provide the before and after change attributes.
> 
> Second, RFC 8276 (NFSv4 extended attribute support) specifies that
> delegations should be recalled (8.4.2.4, 8.4.4.4) when a SETXATTR
> or REMOVEXATTR operation is performed. So, like with other fs
> operations, try to break the delegation. The _locked version of
> these operations will not wait for the delegation to be successfully
> broken, instead returning an error if it wasn't, so that the NFS
> server code can return NFS4ERR_DELAY to the client (similar to
> what e.g. vfs_link does).
> 
> Signed-off-by: Frank van der Linden <fllinden@amazon.com>

Frank, I appreciate the verbosity of the patch descriptions, and
thanks very much for splitting the client and server work into
separate series.

[cel@klimt linux]$ scripts/get_maintainer.pl fs/xattr.c
Alexander Viro <viro@zeniv.linux.org.uk> (maintainer:FILESYSTEMS (VFS and infrastructure))
linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure))
linux-kernel@vger.kernel.org (open list)
[cel@klimt linux]$ 

So patches like this one and 13/14 (or perhaps the whole series)
needs to be cc: linux-fsdevel@vger.kernel.org. At least those
two patches in particular will need an Acked-by: from viro.


> ---
> fs/xattr.c            | 63 +++++++++++++++++++++++++++++++++++++++++++++------
> include/linux/xattr.h |  2 ++
> 2 files changed, 58 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 90dd78f0eb27..58013bcbc333 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -204,10 +204,10 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
> 	return error;
> }
> 
> -
> int
> -vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
> -		size_t size, int flags)
> +__vfs_setxattr_locked(struct dentry *dentry, const char *name,
> +		const void *value, size_t size, int flags,
> +		struct inode **delegated_inode)

Since you will need to repost, please consider adding a Doxygen
comment in front of newly introduced global APIs. Such a comment
would be an appropriate place to add non-NFS-related explanatory
text you have provided in the patch description.

Goes for global APIs introduced in other patches too.


> {
> 	struct inode *inode = dentry->d_inode;
> 	int error;
> @@ -216,15 +216,40 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
> 	if (error)
> 		return error;
> 
> -	inode_lock(inode);
> 	error = security_inode_setxattr(dentry, name, value, size, flags);
> 	if (error)
> 		goto out;
> 
> +	error = try_break_deleg(inode, delegated_inode);
> +	if (error)
> +		goto out;
> +
> 	error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
> 
> out:
> +	return error;
> +}
> +EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
> +
> +int
> +vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
> +		size_t size, int flags)
> +{
> +	struct inode *inode = dentry->d_inode;
> +	struct inode *delegated_inode = NULL;
> +	int error;
> +
> +retry_deleg:
> +	inode_lock(inode);
> +	error = __vfs_setxattr_locked(dentry, name, value, size, flags,
> +	    &delegated_inode);
> 	inode_unlock(inode);
> +
> +	if (delegated_inode) {
> +		error = break_deleg_wait(&delegated_inode);
> +		if (!error)
> +			goto retry_deleg;
> +	}
> 	return error;
> }
> EXPORT_SYMBOL_GPL(vfs_setxattr);
> @@ -379,7 +404,8 @@ __vfs_removexattr(struct dentry *dentry, const char *name)
> EXPORT_SYMBOL(__vfs_removexattr);
> 
> int
> -vfs_removexattr(struct dentry *dentry, const char *name)
> +__vfs_removexattr_locked(struct dentry *dentry, const char *name,
> +		struct inode **delegated_inode)
> {
> 	struct inode *inode = dentry->d_inode;
> 	int error;
> @@ -388,11 +414,14 @@ vfs_removexattr(struct dentry *dentry, const char *name)
> 	if (error)
> 		return error;
> 
> -	inode_lock(inode);
> 	error = security_inode_removexattr(dentry, name);
> 	if (error)
> 		goto out;
> 
> +	error = try_break_deleg(inode, delegated_inode);
> +	if (error)
> +		goto out;
> +
> 	error = __vfs_removexattr(dentry, name);
> 
> 	if (!error) {
> @@ -401,12 +430,32 @@ vfs_removexattr(struct dentry *dentry, const char *name)
> 	}
> 
> out:
> +	return error;
> +}
> +EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
> +
> +int
> +vfs_removexattr(struct dentry *dentry, const char *name)
> +{
> +	struct inode *inode = dentry->d_inode;
> +	struct inode *delegated_inode = NULL;
> +	int error;
> +
> +retry_deleg:
> +	inode_lock(inode);
> +	error = __vfs_removexattr_locked(dentry, name, &delegated_inode);
> 	inode_unlock(inode);
> +
> +	if (delegated_inode) {
> +		error = break_deleg_wait(&delegated_inode);
> +		if (!error)
> +			goto retry_deleg;
> +	}
> +
> 	return error;
> }
> EXPORT_SYMBOL_GPL(vfs_removexattr);
> 
> -
> /*
>  * Extended attribute SET operations
>  */
> diff --git a/include/linux/xattr.h b/include/linux/xattr.h
> index 6dad031be3c2..3a71ad716da5 100644
> --- a/include/linux/xattr.h
> +++ b/include/linux/xattr.h
> @@ -51,8 +51,10 @@ ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
> ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
> int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
> int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
> +int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
> int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
> int __vfs_removexattr(struct dentry *, const char *);
> +int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **);
> int vfs_removexattr(struct dentry *, const char *);
> 
> ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
> -- 
> 2.16.6
> 

--
Chuck Lever

Re: [PATCH 02/14] xattr: modify vfs_{set,remove}xattr for NFS server use

[J. Bruce Fields]

On Wed, Mar 11, 2020 at 07:59:42PM +0000, Frank van der Linden wrote:
> To be called from the upcoming NFS server xattr code, the vfs_removexattr
> and vfs_setxattr need some modifications.
> 
> First, they need to grow a _locked variant, since the NFS server code
> will call this with i_rwsem held. It needs to do that in fh_lock to be
> able to atomically provide the before and after change attributes.

Unlike NFSv3, NFSv4+ doesn't support atomic before- and after- change
attributes for setattr.  Trying to take advantage of that assumption
might result in worse code, though.

> Second, RFC 8276 (NFSv4 extended attribute support) specifies that
> delegations should be recalled (8.4.2.4, 8.4.4.4) when a SETXATTR
> or REMOVEXATTR operation is performed. So, like with other fs
> operations, try to break the delegation. The _locked version of
> these operations will not wait for the delegation to be successfully
> broken, instead returning an error if it wasn't, so that the NFS
> server code can return NFS4ERR_DELAY to the client (similar to
> what e.g. vfs_link does).

Is there a preexisting bug here?  Even without NFS support for xattrs, a
local setxattr on the filesystem should still revoke any delegations
held by remote NFS clients.  I couldn't tell whether we're getting that
right from a quick look at the current code.

--b.

> 
> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
>  fs/xattr.c            | 63 +++++++++++++++++++++++++++++++++++++++++++++------
>  include/linux/xattr.h |  2 ++
>  2 files changed, 58 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 90dd78f0eb27..58013bcbc333 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -204,10 +204,10 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
>  	return error;
>  }
>  
> -
>  int
> -vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
> -		size_t size, int flags)
> +__vfs_setxattr_locked(struct dentry *dentry, const char *name,
> +		const void *value, size_t size, int flags,
> +		struct inode **delegated_inode)
>  {
>  	struct inode *inode = dentry->d_inode;
>  	int error;
> @@ -216,15 +216,40 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
>  	if (error)
>  		return error;
>  
> -	inode_lock(inode);
>  	error = security_inode_setxattr(dentry, name, value, size, flags);
>  	if (error)
>  		goto out;
>  
> +	error = try_break_deleg(inode, delegated_inode);
> +	if (error)
> +		goto out;
> +
>  	error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
>  
>  out:
> +	return error;
> +}
> +EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
> +
> +int
> +vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
> +		size_t size, int flags)
> +{
> +	struct inode *inode = dentry->d_inode;
> +	struct inode *delegated_inode = NULL;
> +	int error;
> +
> +retry_deleg:
> +	inode_lock(inode);
> +	error = __vfs_setxattr_locked(dentry, name, value, size, flags,
> +	    &delegated_inode);
>  	inode_unlock(inode);
> +
> +	if (delegated_inode) {
> +		error = break_deleg_wait(&delegated_inode);
> +		if (!error)
> +			goto retry_deleg;
> +	}
>  	return error;
>  }
>  EXPORT_SYMBOL_GPL(vfs_setxattr);
> @@ -379,7 +404,8 @@ __vfs_removexattr(struct dentry *dentry, const char *name)
>  EXPORT_SYMBOL(__vfs_removexattr);
>  
>  int
> -vfs_removexattr(struct dentry *dentry, const char *name)
> +__vfs_removexattr_locked(struct dentry *dentry, const char *name,
> +		struct inode **delegated_inode)
>  {
>  	struct inode *inode = dentry->d_inode;
>  	int error;
> @@ -388,11 +414,14 @@ vfs_removexattr(struct dentry *dentry, const char *name)
>  	if (error)
>  		return error;
>  
> -	inode_lock(inode);
>  	error = security_inode_removexattr(dentry, name);
>  	if (error)
>  		goto out;
>  
> +	error = try_break_deleg(inode, delegated_inode);
> +	if (error)
> +		goto out;
> +
>  	error = __vfs_removexattr(dentry, name);
>  
>  	if (!error) {
> @@ -401,12 +430,32 @@ vfs_removexattr(struct dentry *dentry, const char *name)
>  	}
>  
>  out:
> +	return error;
> +}
> +EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
> +
> +int
> +vfs_removexattr(struct dentry *dentry, const char *name)
> +{
> +	struct inode *inode = dentry->d_inode;
> +	struct inode *delegated_inode = NULL;
> +	int error;
> +
> +retry_deleg:
> +	inode_lock(inode);
> +	error = __vfs_removexattr_locked(dentry, name, &delegated_inode);
>  	inode_unlock(inode);
> +
> +	if (delegated_inode) {
> +		error = break_deleg_wait(&delegated_inode);
> +		if (!error)
> +			goto retry_deleg;
> +	}
> +
>  	return error;
>  }
>  EXPORT_SYMBOL_GPL(vfs_removexattr);
>  
> -
>  /*
>   * Extended attribute SET operations
>   */
> diff --git a/include/linux/xattr.h b/include/linux/xattr.h
> index 6dad031be3c2..3a71ad716da5 100644
> --- a/include/linux/xattr.h
> +++ b/include/linux/xattr.h
> @@ -51,8 +51,10 @@ ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
>  ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
>  int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
>  int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
> +int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
>  int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
>  int __vfs_removexattr(struct dentry *, const char *);
> +int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **);
>  int vfs_removexattr(struct dentry *, const char *);
>  
>  ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
> -- 
> 2.16.6

Re: [PATCH 02/14] xattr: modify vfs_{set, remove}xattr for NFS server use

[Frank van der Linden]

On Fri, Mar 13, 2020 at 11:35:49AM -0400, J. Bruce Fields wrote:
> 
> 
> On Wed, Mar 11, 2020 at 07:59:42PM +0000, Frank van der Linden wrote:
> > Second, RFC 8276 (NFSv4 extended attribute support) specifies that
> > delegations should be recalled (8.4.2.4, 8.4.4.4) when a SETXATTR
> > or REMOVEXATTR operation is performed. So, like with other fs
> > operations, try to break the delegation. The _locked version of
> > these operations will not wait for the delegation to be successfully
> > broken, instead returning an error if it wasn't, so that the NFS
> > server code can return NFS4ERR_DELAY to the client (similar to
> > what e.g. vfs_link does).
> 
> Is there a preexisting bug here?  Even without NFS support for xattrs, a
> local setxattr on the filesystem should still revoke any delegations
> held by remote NFS clients.  I couldn't tell whether we're getting that
> right from a quick look at the current code.
> 
> --b.

I think there's currently a bug if that's the expected behavior, yes.
Attribute changes will call notify_change(), and other methods (unlink,
link, rename) call try_break_deleg(). But the xattr entry points
don't do that, which is why I added it.

- Frank

Re: [PATCH 02/14] xattr: modify vfs_{set, remove}xattr for NFS server use

[J. Bruce Fields]

On Fri, Mar 13, 2020 at 04:07:02PM +0000, Frank van der Linden wrote:
> On Fri, Mar 13, 2020 at 11:35:49AM -0400, J. Bruce Fields wrote:
> > 
> > 
> > On Wed, Mar 11, 2020 at 07:59:42PM +0000, Frank van der Linden wrote:
> > > Second, RFC 8276 (NFSv4 extended attribute support) specifies that
> > > delegations should be recalled (8.4.2.4, 8.4.4.4) when a SETXATTR
> > > or REMOVEXATTR operation is performed. So, like with other fs
> > > operations, try to break the delegation. The _locked version of
> > > these operations will not wait for the delegation to be successfully
> > > broken, instead returning an error if it wasn't, so that the NFS
> > > server code can return NFS4ERR_DELAY to the client (similar to
> > > what e.g. vfs_link does).
> > 
> > Is there a preexisting bug here?  Even without NFS support for xattrs, a
> > local setxattr on the filesystem should still revoke any delegations
> > held by remote NFS clients.  I couldn't tell whether we're getting that
> > right from a quick look at the current code.
> > 
> > --b.
> 
> I think there's currently a bug if that's the expected behavior, yes.
> Attribute changes will call notify_change(), and other methods (unlink,
> link, rename) call try_break_deleg(). But the xattr entry points
> don't do that, which is why I added it.

Got it, thanks.  In that case I'd move this patch (or the part of it
required to fix that bug) to the front of the series and add a

	Cc: stable@vger.kernel.org

--b.

[PATCH 03/14] nfsd: split off the write decode code in to a separate function

[Frank van der Linden]

nfs4_decode_write has code to parse incoming XDR write data in to
a kvec head, and a list of pages.

Put this code in to a separate function, so that it can be used
later by the xattr code, for setxattr. No functional change.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4xdr.c | 72 ++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 42 insertions(+), 30 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 9761512674a0..6e7fc6a9931e 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -257,6 +257,44 @@ svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, u32 len)
 	return p;
 }
 
+static __be32
+svcxdr_construct_vector(struct nfsd4_compoundargs *argp, struct kvec *head,
+			struct page ***pagelist, u32 buflen)
+{
+	int avail;
+	int len;
+	int pages;
+
+	/* Sorry .. no magic macros for this.. *
+	 * READ_BUF(write->wr_buflen);
+	 * SAVEMEM(write->wr_buf, write->wr_buflen);
+	 */
+	avail = (char *)argp->end - (char *)argp->p;
+	if (avail + argp->pagelen < buflen) {
+		dprintk("NFSD: xdr error (%s:%d)\n",
+			       __FILE__, __LINE__);
+		return nfserr_bad_xdr;
+	}
+	head->iov_base = argp->p;
+	head->iov_len = avail;
+	*pagelist = argp->pagelist;
+
+	len = XDR_QUADLEN(buflen) << 2;
+	if (len >= avail) {
+		len -= avail;
+
+		pages = len >> PAGE_SHIFT;
+		argp->pagelist += pages;
+		argp->pagelen -= pages * PAGE_SIZE;
+		len -= pages * PAGE_SIZE;
+
+		next_decode_page(argp);
+	}
+	argp->p += XDR_QUADLEN(len);
+
+	return 0;
+}
+
 /**
  * savemem - duplicate a chunk of memory for later processing
  * @argp: NFSv4 compound argument structure to be freed with
@@ -1265,8 +1303,6 @@ nfsd4_decode_verify(struct nfsd4_compoundargs *argp, struct nfsd4_verify *verify
 static __be32
 nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
 {
-	int avail;
-	int len;
 	DECODE_HEAD;
 
 	status = nfsd4_decode_stateid(argp, &write->wr_stateid);
@@ -1279,34 +1315,10 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
 		goto xdr_error;
 	write->wr_buflen = be32_to_cpup(p++);
 
-	/* Sorry .. no magic macros for this.. *
-	 * READ_BUF(write->wr_buflen);
-	 * SAVEMEM(write->wr_buf, write->wr_buflen);
-	 */
-	avail = (char*)argp->end - (char*)argp->p;
-	if (avail + argp->pagelen < write->wr_buflen) {
-		dprintk("NFSD: xdr error (%s:%d)\n",
-				__FILE__, __LINE__);
-		goto xdr_error;
-	}
-	write->wr_head.iov_base = p;
-	write->wr_head.iov_len = avail;
-	write->wr_pagelist = argp->pagelist;
-
-	len = XDR_QUADLEN(write->wr_buflen) << 2;
-	if (len >= avail) {
-		int pages;
-
-		len -= avail;
-
-		pages = len >> PAGE_SHIFT;
-		argp->pagelist += pages;
-		argp->pagelen -= pages * PAGE_SIZE;
-		len -= pages * PAGE_SIZE;
-
-		next_decode_page(argp);
-	}
-	argp->p += XDR_QUADLEN(len);
+	status = svcxdr_construct_vector(argp, &write->wr_head,
+					 &write->wr_pagelist, write->wr_buflen);
+	if (status)
+		return status;
 
 	DECODE_TAIL;
 }
-- 
2.16.6

[PATCH 04/14] nfsd: make sure the nfsd4_ops array has the right size

[Frank van der Linden]

The nfsd4_ops was initialized by initializing individual indices (op
numbers). So, the size of the array was determined by the largest
op number.

Some operations are enabled conditionally, based on config options.
If a conditionally enabled operation were to be the highest numbered
operation, the code (through OPDESC) would attempt to access memory
beyond the end of the array. This currently can't happen, since the
highest numbered op is not conditional, but it might in the future.

So, always size the array with LAST_NFS4_OP + 1.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 0e75f7fb5fec..5de6449e6ff8 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2699,7 +2699,7 @@ static inline u32 nfsd4_seek_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
 	return (op_encode_hdr_size + 3) * sizeof(__be32);
 }
 
-static const struct nfsd4_operation nfsd4_ops[] = {
+static const struct nfsd4_operation nfsd4_ops[LAST_NFS4_OP + 1] = {
 	[OP_ACCESS] = {
 		.op_func = nfsd4_access,
 		.op_name = "OP_ACCESS",
-- 
2.16.6

[PATCH 05/14] nfsd: add defines for NFSv4.2 extended attribute support

[Frank van der Linden]

Add defines for server-side extended attribute support. Most have
already been added as part of client support, but these are
the network order error codes for the noxattr and xattr2big errors,
and the addition of the xattr support to the supported file
attributes (if configured).

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfsd.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 2ab5569126b8..362d481b28c9 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -281,6 +281,8 @@ void		nfsd_lockd_shutdown(void);
 #define nfserr_wrong_lfs		cpu_to_be32(NFS4ERR_WRONG_LFS)
 #define nfserr_badlabel			cpu_to_be32(NFS4ERR_BADLABEL)
 #define nfserr_file_open		cpu_to_be32(NFS4ERR_FILE_OPEN)
+#define nfserr_xattr2big		cpu_to_be32(NFS4ERR_XATTR2BIG)
+#define nfserr_noxattr			cpu_to_be32(NFS4ERR_NOXATTR)
 
 /* error codes for internal use */
 /* if a request fails due to kmalloc failure, it gets dropped.
@@ -382,7 +384,8 @@ void		nfsd_lockd_shutdown(void);
 	(NFSD4_1_SUPPORTED_ATTRS_WORD2 | \
 	FATTR4_WORD2_CHANGE_ATTR_TYPE | \
 	FATTR4_WORD2_MODE_UMASK | \
-	NFSD4_2_SECURITY_ATTRS)
+	NFSD4_2_SECURITY_ATTRS | \
+	FATTR4_WORD2_XATTR_SUPPORT)
 
 extern const u32 nfsd_suppattrs[3][3];
 
-- 
2.16.6

Re: [PATCH 05/14] nfsd: add defines for NFSv4.2 extended attribute support

[Chuck Lever]

> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> Add defines for server-side extended attribute support. Most have
> already been added as part of client support, but these are
> the network order error codes for the noxattr and xattr2big errors,
> and the addition of the xattr support to the supported file
> attributes (if configured).
> 
> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/nfsd/nfsd.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
> index 2ab5569126b8..362d481b28c9 100644
> --- a/fs/nfsd/nfsd.h
> +++ b/fs/nfsd/nfsd.h
> @@ -281,6 +281,8 @@ void		nfsd_lockd_shutdown(void);
> #define nfserr_wrong_lfs		cpu_to_be32(NFS4ERR_WRONG_LFS)
> #define nfserr_badlabel			cpu_to_be32(NFS4ERR_BADLABEL)
> #define nfserr_file_open		cpu_to_be32(NFS4ERR_FILE_OPEN)
> +#define nfserr_xattr2big		cpu_to_be32(NFS4ERR_XATTR2BIG)
> +#define nfserr_noxattr			cpu_to_be32(NFS4ERR_NOXATTR)

Not clear to me why these shouldn't go into 01/14


> /* error codes for internal use */
> /* if a request fails due to kmalloc failure, it gets dropped.
> @@ -382,7 +384,8 @@ void		nfsd_lockd_shutdown(void);
> 	(NFSD4_1_SUPPORTED_ATTRS_WORD2 | \
> 	FATTR4_WORD2_CHANGE_ATTR_TYPE | \
> 	FATTR4_WORD2_MODE_UMASK | \
> -	NFSD4_2_SECURITY_ATTRS)
> +	NFSD4_2_SECURITY_ATTRS | \
> +	FATTR4_WORD2_XATTR_SUPPORT)

Should this instead be added, say, in 14/14 ?


> extern const u32 nfsd_suppattrs[3][3];
> 
> -- 
> 2.16.6
> 

--
Chuck Lever

[PATCH 06/14] nfsd: define xattr functions to call in to their vfs counterparts

[Frank van der Linden]

This adds the filehandle based functions for the xattr operations
that call in to the vfs layer to do the actual work.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/vfs.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/nfsd/vfs.h |  10 +++++
 2 files changed, 140 insertions(+)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 0aa02eb18bd3..115449009bc0 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -2058,6 +2058,136 @@ static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
 	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
 }
 
+#ifdef CONFIG_NFSD_V4
+/*
+ * Helper function to translate error numbers. In the case of xattr operations,
+ * some error codes need to be translated outside of the standard translations.
+ *
+ * ENODATA needs to be translated to nfserr_noxattr.
+ * E2BIG to nfserr_xattr2big.
+ *
+ * Additionally, vfs_listxattr can return -ERANGE. This means that the
+ * file has too many extended attributes to retrieve inside an
+ * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
+ * filesystems will allow the adding of extended attributes until they hit
+ * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
+ * So, at that point, the attributes are present and valid, but can't
+ * be retrieved using listxattr, since the upper level xattr code enforces
+ * the XATTR_LIST_MAX limit.
+ *
+ * This bug means that we need to deal with listxattr returning -ERANGE. The
+ * best mapping is to return TOOSMALL.
+ */
+static __be32
+nfsd_xattr_errno(int err)
+{
+	switch (err) {
+	case -ENODATA:
+		return nfserr_noxattr;
+	case -E2BIG:
+		return nfserr_xattr2big;
+	case -ERANGE:
+		return nfserr_toosmall;
+	}
+	return nfserrno(err);
+}
+
+__be32
+nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
+	      void *buf, int *lenp)
+{
+	ssize_t lerr;
+	int err;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
+	if (err)
+		return err;
+
+	lerr = vfs_getxattr(fhp->fh_dentry, name, buf, *lenp);
+	if (lerr < 0)
+		err = nfsd_xattr_errno(lerr);
+	else
+		*lenp = lerr;
+
+	return err;
+}
+
+__be32
+nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, void *buf, int *lenp)
+{
+	ssize_t lerr;
+	int err;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
+	if (err)
+		return err;
+
+	lerr = vfs_listxattr(fhp->fh_dentry, buf, *lenp);
+
+	if (lerr < 0)
+		err = nfsd_xattr_errno(lerr);
+	else
+		*lenp = lerr;
+
+	return err;
+}
+
+/*
+ * Removexattr and setxattr need to call fh_lock to both lock the inode
+ * and set the change attribute. Since the top-level vfs_removexattr
+ * and vfs_setxattr calls already do their own inode_lock calls, call
+ * the _locked variant. Pass in a NULL pointer for delegated_inode,
+ * and let the client deal with NFS4ERR_DELAY (same as with e.g.
+ * setattr and remove).
+ */
+__be32
+nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
+{
+	int err, ret;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
+	if (err)
+		return err;
+
+	ret = fh_want_write(fhp);
+	if (ret)
+		return nfserrno(ret);
+
+	fh_lock(fhp);
+
+	ret = __vfs_removexattr_locked(fhp->fh_dentry, name, NULL);
+
+	fh_unlock(fhp);
+	fh_drop_write(fhp);
+
+	return nfsd_xattr_errno(ret);
+}
+
+__be32
+nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
+	      void *buf, u32 len, u32 flags)
+{
+	int err, ret;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
+	if (err)
+		return err;
+
+	ret = fh_want_write(fhp);
+	if (ret)
+		return nfserrno(ret);
+	fh_lock(fhp);
+
+	ret = __vfs_setxattr_locked(fhp->fh_dentry, name, buf, len, flags,
+				    NULL);
+
+	fh_unlock(fhp);
+	fh_drop_write(fhp);
+
+	return nfsd_xattr_errno(ret);
+}
+#endif
+
 /*
  * Check for a user's access permissions to this inode.
  */
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 3eb660ad80d1..2d2cf5b0543b 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -76,6 +76,16 @@ __be32		do_nfsd_create(struct svc_rqst *, struct svc_fh *,
 __be32		nfsd_commit(struct svc_rqst *, struct svc_fh *,
 				loff_t, unsigned long, __be32 *verf);
 #endif /* CONFIG_NFSD_V3 */
+#ifdef CONFIG_NFSD_V4
+__be32		nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    char *name, void *buf, int *lenp);
+__be32		nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    void *buf, int *lenp);
+__be32		nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    char *name);
+__be32		nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
+			    char *name, void *buf, u32 len, u32 flags);
+#endif
 int 		nfsd_open_break_lease(struct inode *, int);
 __be32		nfsd_open(struct svc_rqst *, struct svc_fh *, umode_t,
 				int, struct file **);
-- 
2.16.6

Re: [PATCH 06/14] nfsd: define xattr functions to call in to their vfs counterparts

[kbuild test robot]

Hi Frank,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on nfsd/nfsd-next]
[also build test WARNING on nfs/linux-next linus/master v5.6-rc5 next-20200311]
[cannot apply to cel/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Frank-van-der-Linden/server-side-user-xattr-support-RFC-8276/20200312-064928
base:   git://linux-nfs.org/~bfields/linux.git nfsd-next
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.1-174-g094d5a94-dirty
        make ARCH=x86_64 allmodconfig
        make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)

>> fs/nfsd/vfs.c:2102:13: sparse: sparse: incorrect type in assignment (different base types) @@    expected int err @@    got restricted __int err @@
>> fs/nfsd/vfs.c:2102:13: sparse:    expected int err
>> fs/nfsd/vfs.c:2102:13: sparse:    got restricted __be32
>> fs/nfsd/vfs.c:2104:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
>> fs/nfsd/vfs.c:2104:24: sparse:    expected restricted __be32
>> fs/nfsd/vfs.c:2104:24: sparse:    got int err
   fs/nfsd/vfs.c:2108:21: sparse: sparse: incorrect type in assignment (different base types) @@    expected int err @@    got restricted __int err @@
   fs/nfsd/vfs.c:2108:21: sparse:    expected int err
   fs/nfsd/vfs.c:2108:21: sparse:    got restricted __be32
   fs/nfsd/vfs.c:2112:16: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/vfs.c:2112:16: sparse:    expected restricted __be32
   fs/nfsd/vfs.c:2112:16: sparse:    got int err
   fs/nfsd/vfs.c:2121:13: sparse: sparse: incorrect type in assignment (different base types) @@    expected int err @@    got restricted __int err @@
   fs/nfsd/vfs.c:2121:13: sparse:    expected int err
   fs/nfsd/vfs.c:2121:13: sparse:    got restricted __be32
   fs/nfsd/vfs.c:2123:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/vfs.c:2123:24: sparse:    expected restricted __be32
   fs/nfsd/vfs.c:2123:24: sparse:    got int err
   fs/nfsd/vfs.c:2128:21: sparse: sparse: incorrect type in assignment (different base types) @@    expected int err @@    got restricted __int err @@
   fs/nfsd/vfs.c:2128:21: sparse:    expected int err
   fs/nfsd/vfs.c:2128:21: sparse:    got restricted __be32
   fs/nfsd/vfs.c:2132:16: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/vfs.c:2132:16: sparse:    expected restricted __be32
   fs/nfsd/vfs.c:2132:16: sparse:    got int err
   fs/nfsd/vfs.c:2148:13: sparse: sparse: incorrect type in assignment (different base types) @@    expected int err @@    got restricted __int err @@
   fs/nfsd/vfs.c:2148:13: sparse:    expected int err
   fs/nfsd/vfs.c:2148:13: sparse:    got restricted __be32
   fs/nfsd/vfs.c:2150:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/vfs.c:2150:24: sparse:    expected restricted __be32
   fs/nfsd/vfs.c:2150:24: sparse:    got int err
   fs/nfsd/vfs.c:2172:13: sparse: sparse: incorrect type in assignment (different base types) @@    expected int err @@    got restricted __int err @@
   fs/nfsd/vfs.c:2172:13: sparse:    expected int err
   fs/nfsd/vfs.c:2172:13: sparse:    got restricted __be32
   fs/nfsd/vfs.c:2174:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/vfs.c:2174:24: sparse:    expected restricted __be32
   fs/nfsd/vfs.c:2174:24: sparse:    got int err

vim +2102 fs/nfsd/vfs.c

  2094	
  2095	__be32
  2096	nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
  2097		      void *buf, int *lenp)
  2098	{
  2099		ssize_t lerr;
  2100		int err;
  2101	
> 2102		err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
  2103		if (err)
> 2104			return err;
  2105	
  2106		lerr = vfs_getxattr(fhp->fh_dentry, name, buf, *lenp);
  2107		if (lerr < 0)
  2108			err = nfsd_xattr_errno(lerr);
  2109		else
  2110			*lenp = lerr;
  2111	
  2112		return err;
  2113	}
  2114	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH 06/14] nfsd: define xattr functions to call in to their vfs counterparts

[Chuck Lever]

> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> This adds the filehandle based functions for the xattr operations
> that call in to the vfs layer to do the actual work.

Before posting again, use "make C=1" to clear up new sparse
errors, and scripts/checkpatch.pl to find and correct whitespace
damage introduced in this series.


> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/nfsd/vfs.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/nfsd/vfs.h |  10 +++++
> 2 files changed, 140 insertions(+)
> 
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 0aa02eb18bd3..115449009bc0 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -2058,6 +2058,136 @@ static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
> 	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
> }
> 
> +#ifdef CONFIG_NFSD_V4
> +/*
> + * Helper function to translate error numbers. In the case of xattr operations,
> + * some error codes need to be translated outside of the standard translations.
> + *
> + * ENODATA needs to be translated to nfserr_noxattr.
> + * E2BIG to nfserr_xattr2big.
> + *
> + * Additionally, vfs_listxattr can return -ERANGE. This means that the
> + * file has too many extended attributes to retrieve inside an
> + * XATTR_LIST_MAX sized buffer. This is a bug in the xattr implementation:
> + * filesystems will allow the adding of extended attributes until they hit
> + * their own internal limit. This limit may be larger than XATTR_LIST_MAX.
> + * So, at that point, the attributes are present and valid, but can't
> + * be retrieved using listxattr, since the upper level xattr code enforces
> + * the XATTR_LIST_MAX limit.
> + *
> + * This bug means that we need to deal with listxattr returning -ERANGE. The
> + * best mapping is to return TOOSMALL.
> + */
> +static __be32
> +nfsd_xattr_errno(int err)
> +{
> +	switch (err) {
> +	case -ENODATA:
> +		return nfserr_noxattr;
> +	case -E2BIG:
> +		return nfserr_xattr2big;
> +	case -ERANGE:
> +		return nfserr_toosmall;
> +	}
> +	return nfserrno(err);
> +}
> +
> +__be32
> +nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
> +	      void *buf, int *lenp)
> +{
> +	ssize_t lerr;
> +	int err;
> +
> +	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
> +	if (err)
> +		return err;
> +
> +	lerr = vfs_getxattr(fhp->fh_dentry, name, buf, *lenp);
> +	if (lerr < 0)
> +		err = nfsd_xattr_errno(lerr);
> +	else
> +		*lenp = lerr;
> +
> +	return err;
> +}
> +
> +__be32
> +nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, void *buf, int *lenp)
> +{
> +	ssize_t lerr;
> +	int err;
> +
> +	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ);
> +	if (err)
> +		return err;
> +
> +	lerr = vfs_listxattr(fhp->fh_dentry, buf, *lenp);
> +
> +	if (lerr < 0)
> +		err = nfsd_xattr_errno(lerr);
> +	else
> +		*lenp = lerr;
> +
> +	return err;
> +}
> +
> +/*
> + * Removexattr and setxattr need to call fh_lock to both lock the inode
> + * and set the change attribute. Since the top-level vfs_removexattr
> + * and vfs_setxattr calls already do their own inode_lock calls, call
> + * the _locked variant. Pass in a NULL pointer for delegated_inode,
> + * and let the client deal with NFS4ERR_DELAY (same as with e.g.
> + * setattr and remove).
> + */
> +__be32
> +nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
> +{
> +	int err, ret;
> +
> +	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
> +	if (err)
> +		return err;
> +
> +	ret = fh_want_write(fhp);
> +	if (ret)
> +		return nfserrno(ret);
> +
> +	fh_lock(fhp);
> +
> +	ret = __vfs_removexattr_locked(fhp->fh_dentry, name, NULL);
> +
> +	fh_unlock(fhp);
> +	fh_drop_write(fhp);
> +
> +	return nfsd_xattr_errno(ret);
> +}
> +
> +__be32
> +nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
> +	      void *buf, u32 len, u32 flags)
> +{
> +	int err, ret;
> +
> +	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_WRITE);
> +	if (err)
> +		return err;
> +
> +	ret = fh_want_write(fhp);
> +	if (ret)
> +		return nfserrno(ret);
> +	fh_lock(fhp);
> +
> +	ret = __vfs_setxattr_locked(fhp->fh_dentry, name, buf, len, flags,
> +				    NULL);
> +
> +	fh_unlock(fhp);
> +	fh_drop_write(fhp);
> +
> +	return nfsd_xattr_errno(ret);
> +}
> +#endif
> +
> /*
>  * Check for a user's access permissions to this inode.
>  */
> diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
> index 3eb660ad80d1..2d2cf5b0543b 100644
> --- a/fs/nfsd/vfs.h
> +++ b/fs/nfsd/vfs.h
> @@ -76,6 +76,16 @@ __be32		do_nfsd_create(struct svc_rqst *, struct svc_fh *,
> __be32		nfsd_commit(struct svc_rqst *, struct svc_fh *,
> 				loff_t, unsigned long, __be32 *verf);
> #endif /* CONFIG_NFSD_V3 */
> +#ifdef CONFIG_NFSD_V4
> +__be32		nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
> +			    char *name, void *buf, int *lenp);
> +__be32		nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
> +			    void *buf, int *lenp);
> +__be32		nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
> +			    char *name);
> +__be32		nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
> +			    char *name, void *buf, u32 len, u32 flags);
> +#endif
> int 		nfsd_open_break_lease(struct inode *, int);
> __be32		nfsd_open(struct svc_rqst *, struct svc_fh *, umode_t,
> 				int, struct file **);
> -- 
> 2.16.6
> 

--
Chuck Lever

Re: [PATCH 06/14] nfsd: define xattr functions to call in to their vfs counterparts

[Frank van der Linden]

On Thu, Mar 12, 2020 at 12:23:57PM -0400, Chuck Lever wrote:
> > On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> >
> > This adds the filehandle based functions for the xattr operations
> > that call in to the vfs layer to do the actual work.
> 
> Before posting again, use "make C=1" to clear up new sparse
> errors, and scripts/checkpatch.pl to find and correct whitespace
> damage introduced in this series.

Hi Chuck,

Thanks for this comment (and the other ones).

I forgot to run sparse - I have fixed the __be32/int type mismatches
it flagged in my tree.

I ran checkpath.pl before sending these in. Looks like I missed
one line that is too long. The warnings I didn't fix were:

==
WARNING: function definition argument 'struct dentry *' should also have an identifier name
#156: FILE: include/linux/xattr.h:54:
+int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
==

..changing this would make the prototype declaration of that function not
match with the style of the ones around it (which also don't have argument
names in their declarations) - so I decided not to.

The other one is:

===
WARNING: please, no spaces at the start of a line
#46: FILE: fs/nfsd/vfs.c:616:
+    {^INFS4_ACCESS_XAREAD,^INFSD_MAY_READ^I^I^I},$
===

The warning is correct, but the array that is part of, and the surrounding
accessmap arrays, all have the same spacing. So to both silence checkpacth
and make the code look consistent, I'd have to change the spacing in
all those arrays (nfs3_regaccess, nfs3_diraccess, nfs3_anyaccess).

This didn't seem right, so I didn't do it.

I'll be happy to send a separate whitespace cleanup for that, not sure
if it should be part of this series, though.

Frank

Re: [PATCH 06/14] nfsd: define xattr functions to call in to their vfs counterparts

[Chuck Lever]

> On Mar 12, 2020, at 1:16 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> On Thu, Mar 12, 2020 at 12:23:57PM -0400, Chuck Lever wrote:
>>> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
>>> 
>>> This adds the filehandle based functions for the xattr operations
>>> that call in to the vfs layer to do the actual work.
>> 
>> Before posting again, use "make C=1" to clear up new sparse
>> errors, and scripts/checkpatch.pl to find and correct whitespace
>> damage introduced in this series.
> 
> Hi Chuck,
> 
> Thanks for this comment (and the other ones).
> 
> I forgot to run sparse - I have fixed the __be32/int type mismatches
> it flagged in my tree.
> 
> I ran checkpath.pl before sending these in. Looks like I missed
> one line that is too long. The warnings I didn't fix were:
> 
> ==
> WARNING: function definition argument 'struct dentry *' should also have an identifier name
> #156: FILE: include/linux/xattr.h:54:
> +int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **);
> ==
> 
> ..changing this would make the prototype declaration of that function not
> match with the style of the ones around it (which also don't have argument
> names in their declarations) - so I decided not to.
> 
> The other one is:
> 
> ===
> WARNING: please, no spaces at the start of a line
> #46: FILE: fs/nfsd/vfs.c:616:
> +    {^INFS4_ACCESS_XAREAD,^INFSD_MAY_READ^I^I^I},$
> ===
> 
> The warning is correct, but the array that is part of, and the surrounding
> accessmap arrays, all have the same spacing. So to both silence checkpacth
> and make the code look consistent, I'd have to change the spacing in
> all those arrays (nfs3_regaccess, nfs3_diraccess, nfs3_anyaccess).
> 
> This didn't seem right, so I didn't do it.

Fair enough, please add a comment to that effect to the patch description.


> I'll be happy to send a separate whitespace cleanup for that, not sure
> if it should be part of this series, though.
> 
> Frank

--
Chuck Lever

[PATCH 07/14] nfsd: take xattr bits in to account for permission checks

[Frank van der Linden]

Since the NFSv4.2 extended attributes extension defines 3 new access
bits for xattr operations, take them in to account when validating
what the client is asking for, and when checking permissions.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4proc.c |  8 +++++++-
 fs/nfsd/vfs.c      | 12 ++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 5de6449e6ff8..b573ae1121af 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -566,8 +566,14 @@ nfsd4_access(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	     union nfsd4_op_u *u)
 {
 	struct nfsd4_access *access = &u->access;
+	u32 access_full;
 
-	if (access->ac_req_access & ~NFS3_ACCESS_FULL)
+	access_full = NFS3_ACCESS_FULL;
+	if (cstate->minorversion >= 2)
+		access_full |= NFS4_ACCESS_XALIST | NFS4_ACCESS_XAREAD |
+			       NFS4_ACCESS_XAWRITE;
+
+	if (access->ac_req_access & ~access_full)
 		return nfserr_inval;
 
 	access->ac_resp_access = access->ac_req_access;
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 115449009bc0..19608e690069 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -612,6 +612,12 @@ static struct accessmap	nfs3_regaccess[] = {
     {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
     {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},
 
+#ifdef CONFIG_NFSD_V4
+    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
+    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
+    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
+#endif
+
     {	0,			0				}
 };
 
@@ -622,6 +628,12 @@ static struct accessmap	nfs3_diraccess[] = {
     {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
     {	NFS3_ACCESS_DELETE,	NFSD_MAY_REMOVE			},
 
+#ifdef CONFIG_NFSD_V4
+    {	NFS4_ACCESS_XAREAD,	NFSD_MAY_READ			},
+    {	NFS4_ACCESS_XAWRITE,	NFSD_MAY_WRITE			},
+    {	NFS4_ACCESS_XALIST,	NFSD_MAY_READ			},
+#endif
+
     {	0,			0				}
 };
 
-- 
2.16.6

[PATCH 08/14] nfsd: add structure definitions for xattr requests / responses

[Frank van der Linden]

Add the structures used in extended attribute request / response handling.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/xdr4.h | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index db63d39b1507..66499fb6b567 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -224,6 +224,32 @@ struct nfsd4_putfh {
 	bool		no_verify;	    /* represents foreigh fh */
 };
 
+struct nfsd4_getxattr {
+	char		*getxa_name;		/* request */
+	u32		getxa_len;		/* request */
+	void		*getxa_buf;
+};
+
+struct nfsd4_setxattr {
+	u32		setxa_flags;		/* request */
+	char		*setxa_name;		/* request */
+	char		*setxa_buf;		/* request */
+	u32		setxa_len;		/* request */
+	struct nfsd4_change_info  setxa_cinfo;	/* response */
+};
+
+struct nfsd4_removexattr {
+	char		*rmxa_name;		/* request */
+	struct nfsd4_change_info  rmxa_cinfo;	/* response */
+};
+
+struct nfsd4_listxattrs {
+	u64		lsxa_cookie;		/* request */
+	u32		lsxa_maxcount;		/* request */
+	char		*lsxa_buf;		/* unfiltered buffer (reply) */
+	u32		lsxa_len;		/* unfiltered len (reply) */
+};
+
 struct nfsd4_open {
 	u32		op_claim_type;      /* request */
 	struct xdr_netobj op_fname;	    /* request - everything but CLAIM_PREV */
@@ -649,6 +675,11 @@ struct nfsd4_op {
 		struct nfsd4_offload_status	offload_status;
 		struct nfsd4_copy_notify	copy_notify;
 		struct nfsd4_seek		seek;
+
+		struct nfsd4_getxattr		getxattr;
+		struct nfsd4_setxattr		setxattr;
+		struct nfsd4_listxattrs		listxattrs;
+		struct nfsd4_removexattr	removexattr;
 	} u;
 	struct nfs4_replay *			replay;
 };
-- 
2.16.6

[PATCH 09/14] nfsd: use kvmalloc in svcxdr_tmpalloc

[Frank van der Linden]

For user extended attributes, temp allocations larger than one page
might be needed.

Use kvmalloc/kvfree to accommodate these larger allocations, while not
affecting the performance of the smaller ones.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4xdr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 6e7fc6a9931e..f6322add2992 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -230,7 +230,7 @@ svcxdr_tmpalloc(struct nfsd4_compoundargs *argp, u32 len)
 {
 	struct svcxdr_tmpbuf *tb;
 
-	tb = kmalloc(sizeof(*tb) + len, GFP_KERNEL);
+	tb = kvmalloc(sizeof(*tb) + len, GFP_KERNEL);
 	if (!tb)
 		return NULL;
 	tb->next = argp->to_free;
@@ -4691,7 +4691,7 @@ void nfsd4_release_compoundargs(struct svc_rqst *rqstp)
 	while (args->to_free) {
 		struct svcxdr_tmpbuf *tb = args->to_free;
 		args->to_free = tb->next;
-		kfree(tb);
+		kvfree(tb);
 	}
 }
 
-- 
2.16.6

[PATCH 10/14] nfsd: implement the xattr procedure functions.

[Frank van der Linden]

Implement the main entry points for the *XATTR operations.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4proc.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/nfsd/nfs4xdr.c  |  2 ++
 2 files changed, 75 insertions(+)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index b573ae1121af..a76b9025a357 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2098,6 +2098,79 @@ nfsd4_layoutreturn(struct svc_rqst *rqstp,
 }
 #endif /* CONFIG_NFSD_PNFS */
 
+static __be32
+nfsd4_getxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	       union nfsd4_op_u *u)
+{
+	struct nfsd4_getxattr *getxattr = &u->getxattr;
+
+	return nfsd_getxattr(rqstp, &cstate->current_fh,
+			     getxattr->getxa_name, getxattr->getxa_buf,
+			     &getxattr->getxa_len);
+}
+
+static __be32
+nfsd4_setxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	   union nfsd4_op_u *u)
+{
+	struct nfsd4_setxattr *setxattr = &u->setxattr;
+	int ret;
+
+	if (opens_in_grace(SVC_NET(rqstp)))
+		return nfserr_grace;
+
+	ret = nfsd_setxattr(rqstp, &cstate->current_fh, setxattr->setxa_name,
+			    setxattr->setxa_buf, setxattr->setxa_len,
+			    setxattr->setxa_flags);
+
+	if (!ret)
+		set_change_info(&setxattr->setxa_cinfo, &cstate->current_fh);
+
+	return ret;
+}
+
+static __be32
+nfsd4_listxattrs(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	   union nfsd4_op_u *u)
+{
+	int ret, len;
+
+	/*
+	 * Get the entire list, then copy out only the user attributes
+	 * in the encode function. lsxa_buf was previously allocated as
+	 * tmp svc space, and will be automatically freed later.
+	 */
+	len = XATTR_LIST_MAX;
+
+	ret = nfsd_listxattr(rqstp, &cstate->current_fh, u->listxattrs.lsxa_buf,
+			     &len);
+	if (ret)
+		return ret;
+
+	u->listxattrs.lsxa_len = len;
+
+	return nfs_ok;
+}
+
+static __be32
+nfsd4_removexattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
+	   union nfsd4_op_u *u)
+{
+	struct nfsd4_removexattr *removexattr = &u->removexattr;
+	int ret;
+
+	if (opens_in_grace(SVC_NET(rqstp)))
+		return nfserr_grace;
+
+	ret = nfsd_removexattr(rqstp, &cstate->current_fh,
+	    removexattr->rmxa_name);
+
+	if (!ret)
+		set_change_info(&removexattr->rmxa_cinfo, &cstate->current_fh);
+
+	return ret;
+}
+
 /*
  * NULL call.
  */
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index f6322add2992..b12d7ac6f52c 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -41,6 +41,8 @@
 #include <linux/pagemap.h>
 #include <linux/sunrpc/svcauth_gss.h>
 #include <linux/sunrpc/addr.h>
+#include <linux/xattr.h>
+#include <uapi/linux/xattr.h>
 
 #include "idmap.h"
 #include "acl.h"
-- 
2.16.6

Re: [PATCH 10/14] nfsd: implement the xattr procedure functions.

[kbuild test robot]

Hi Frank,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on nfsd/nfsd-next]
[also build test WARNING on nfs/linux-next linus/master v5.6-rc5 next-20200311]
[cannot apply to cel/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Frank-van-der-Linden/server-side-user-xattr-support-RFC-8276/20200312-064928
base:   git://linux-nfs.org/~bfields/linux.git nfsd-next
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.1-174-g094d5a94-dirty
        make ARCH=x86_64 allmodconfig
        make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)

   fs/nfsd/nfs4proc.c:1541:24: sparse: sparse: incorrect type in assignment (different base types) @@    expected restricted __be32 [assigned] [usertype] status @@    got e] status @@
   fs/nfsd/nfs4proc.c:1541:24: sparse:    expected restricted __be32 [assigned] [usertype] status
   fs/nfsd/nfs4proc.c:1541:24: sparse:    got int
>> fs/nfsd/nfs4proc.c:2122:13: sparse: sparse: incorrect type in assignment (different base types) @@    expected int ret @@    got restricted __int ret @@
>> fs/nfsd/nfs4proc.c:2122:13: sparse:    expected int ret
>> fs/nfsd/nfs4proc.c:2122:13: sparse:    got restricted __be32
>> fs/nfsd/nfs4proc.c:2129:16: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
>> fs/nfsd/nfs4proc.c:2129:16: sparse:    expected restricted __be32
>> fs/nfsd/nfs4proc.c:2129:16: sparse:    got int ret
   fs/nfsd/nfs4proc.c:2145:13: sparse: sparse: incorrect type in assignment (different base types) @@    expected int ret @@    got restricted __int ret @@
   fs/nfsd/nfs4proc.c:2145:13: sparse:    expected int ret
   fs/nfsd/nfs4proc.c:2145:13: sparse:    got restricted __be32
   fs/nfsd/nfs4proc.c:2148:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/nfs4proc.c:2148:24: sparse:    expected restricted __be32
   fs/nfsd/nfs4proc.c:2148:24: sparse:    got int ret
   fs/nfsd/nfs4proc.c:2165:13: sparse: sparse: incorrect type in assignment (different base types) @@    expected int ret @@    got restricted __int ret @@
   fs/nfsd/nfs4proc.c:2165:13: sparse:    expected int ret
   fs/nfsd/nfs4proc.c:2165:13: sparse:    got restricted __be32
   fs/nfsd/nfs4proc.c:2171:16: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/nfs4proc.c:2171:16: sparse:    expected restricted __be32
   fs/nfsd/nfs4proc.c:2171:16: sparse:    got int ret

vim +2122 fs/nfsd/nfs4proc.c

  2111	
  2112	static __be32
  2113	nfsd4_setxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
  2114		   union nfsd4_op_u *u)
  2115	{
  2116		struct nfsd4_setxattr *setxattr = &u->setxattr;
  2117		int ret;
  2118	
  2119		if (opens_in_grace(SVC_NET(rqstp)))
  2120			return nfserr_grace;
  2121	
> 2122		ret = nfsd_setxattr(rqstp, &cstate->current_fh, setxattr->setxa_name,
  2123				    setxattr->setxa_buf, setxattr->setxa_len,
  2124				    setxattr->setxa_flags);
  2125	
  2126		if (!ret)
  2127			set_change_info(&setxattr->setxa_cinfo, &cstate->current_fh);
  2128	
> 2129		return ret;
  2130	}
  2131	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH 10/14] nfsd: implement the xattr procedure functions.

[Chuck Lever]

> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> Implement the main entry points for the *XATTR operations.

This patch triggers "defined but not used" compiler warnings.
These new functions need to be introduced in the same patch
that adds their callsites.

You might consider squashing together all the patches that
only add new NFSD code, for instance.


> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/nfsd/nfs4proc.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/nfsd/nfs4xdr.c  |  2 ++
> 2 files changed, 75 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b573ae1121af..a76b9025a357 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -2098,6 +2098,79 @@ nfsd4_layoutreturn(struct svc_rqst *rqstp,
> }
> #endif /* CONFIG_NFSD_PNFS */
> 
> +static __be32
> +nfsd4_getxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> +	       union nfsd4_op_u *u)
> +{
> +	struct nfsd4_getxattr *getxattr = &u->getxattr;
> +
> +	return nfsd_getxattr(rqstp, &cstate->current_fh,
> +			     getxattr->getxa_name, getxattr->getxa_buf,
> +			     &getxattr->getxa_len);
> +}
> +
> +static __be32
> +nfsd4_setxattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> +	   union nfsd4_op_u *u)
> +{
> +	struct nfsd4_setxattr *setxattr = &u->setxattr;
> +	int ret;
> +
> +	if (opens_in_grace(SVC_NET(rqstp)))
> +		return nfserr_grace;
> +
> +	ret = nfsd_setxattr(rqstp, &cstate->current_fh, setxattr->setxa_name,
> +			    setxattr->setxa_buf, setxattr->setxa_len,
> +			    setxattr->setxa_flags);
> +
> +	if (!ret)
> +		set_change_info(&setxattr->setxa_cinfo, &cstate->current_fh);
> +
> +	return ret;
> +}
> +
> +static __be32
> +nfsd4_listxattrs(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> +	   union nfsd4_op_u *u)
> +{
> +	int ret, len;
> +
> +	/*
> +	 * Get the entire list, then copy out only the user attributes
> +	 * in the encode function. lsxa_buf was previously allocated as
> +	 * tmp svc space, and will be automatically freed later.
> +	 */
> +	len = XATTR_LIST_MAX;
> +
> +	ret = nfsd_listxattr(rqstp, &cstate->current_fh, u->listxattrs.lsxa_buf,
> +			     &len);
> +	if (ret)
> +		return ret;
> +
> +	u->listxattrs.lsxa_len = len;
> +
> +	return nfs_ok;
> +}
> +
> +static __be32
> +nfsd4_removexattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> +	   union nfsd4_op_u *u)
> +{
> +	struct nfsd4_removexattr *removexattr = &u->removexattr;
> +	int ret;
> +
> +	if (opens_in_grace(SVC_NET(rqstp)))
> +		return nfserr_grace;
> +
> +	ret = nfsd_removexattr(rqstp, &cstate->current_fh,
> +	    removexattr->rmxa_name);
> +
> +	if (!ret)
> +		set_change_info(&removexattr->rmxa_cinfo, &cstate->current_fh);
> +
> +	return ret;
> +}
> +
> /*
>  * NULL call.
>  */
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index f6322add2992..b12d7ac6f52c 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -41,6 +41,8 @@
> #include <linux/pagemap.h>
> #include <linux/sunrpc/svcauth_gss.h>
> #include <linux/sunrpc/addr.h>
> +#include <linux/xattr.h>
> +#include <uapi/linux/xattr.h>
> 
> #include "idmap.h"
> #include "acl.h"
> -- 
> 2.16.6
> 

--
Chuck Lever

[PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Frank van der Linden]

Add functions to calculate the reply size for the user extended attribute
operations, and implement the XDR encode / decode logic for these
operations.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4proc.c |  36 +++++
 fs/nfsd/nfs4xdr.c  | 448 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 484 insertions(+)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index a76b9025a357..44d488bdebd9 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -2778,6 +2778,42 @@ static inline u32 nfsd4_seek_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
 	return (op_encode_hdr_size + 3) * sizeof(__be32);
 }
 
+static inline u32 nfsd4_getxattr_rsize(struct svc_rqst *rqstp,
+				       struct nfsd4_op *op)
+{
+	u32 maxcount, rlen;
+
+	maxcount = svc_max_payload(rqstp);
+	rlen = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	return (op_encode_hdr_size + 1 + XDR_QUADLEN(rlen)) * sizeof(__be32);
+}
+
+static inline u32 nfsd4_setxattr_rsize(struct svc_rqst *rqstp,
+				       struct nfsd4_op *op)
+{
+	return (op_encode_hdr_size + op_encode_change_info_maxsz)
+		* sizeof(__be32);
+}
+static inline u32 nfsd4_listxattrs_rsize(struct svc_rqst *rqstp,
+					 struct nfsd4_op *op)
+{
+	u32 maxcount, rlen;
+
+	maxcount = svc_max_payload(rqstp);
+	rlen = min(op->u.listxattrs.lsxa_maxcount, maxcount);
+
+	return (op_encode_hdr_size + 4 + XDR_QUADLEN(rlen)) * sizeof(__be32);
+}
+
+static inline u32 nfsd4_removexattr_rsize(struct svc_rqst *rqstp,
+					  struct nfsd4_op *op)
+{
+	return (op_encode_hdr_size + op_encode_change_info_maxsz)
+		* sizeof(__be32);
+}
+
+
 static const struct nfsd4_operation nfsd4_ops[LAST_NFS4_OP + 1] = {
 	[OP_ACCESS] = {
 		.op_func = nfsd4_access,
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b12d7ac6f52c..41c8b95ca1c5 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1879,6 +1879,224 @@ nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
 	DECODE_TAIL;
 }
 
+/*
+ * XDR data that is more than PAGE_SIZE in size is normally part of a
+ * read or write. However, the size of extended attributes is limited
+ * by the maximum request size, and then further limited by the underlying
+ * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
+ * is 64k). Since there is no kvec- or page-based interface to xattrs,
+ * and we're not dealing with contiguous pages, we need to do some copying.
+ */
+
+/*
+ * Decode int to buffer. Uses head and pages constructed by
+ * svcxdr_construct_vector.
+ */
+static int
+nfsd4_vbuf_from_stream(struct nfsd4_compoundargs *argp, struct kvec *head,
+		       struct page **pages, char **bufp, u32 buflen)
+{
+	char *tmp, *dp;
+	u32 len;
+
+	if (buflen <= head->iov_len) {
+		/*
+		 * We're in luck, the head has enough space. Just return
+		 * the head, no need for copying.
+		 */
+		*bufp = head->iov_base;
+		return 0;
+	}
+
+	tmp = svcxdr_tmpalloc(argp, buflen);
+	if (tmp == NULL)
+		return nfserr_jukebox;
+
+	dp = tmp;
+	memcpy(dp, head->iov_base, head->iov_len);
+	buflen -= head->iov_len;
+	dp += head->iov_len;
+
+	while (buflen > 0) {
+		len = min_t(u32, buflen, PAGE_SIZE);
+		memcpy(dp, page_address(*pages), len);
+
+		buflen -= len;
+		dp += len;
+		pages++;
+	}
+
+	*bufp = tmp;
+	return 0;
+}
+
+/*
+ * Get a user extended attribute name from the XDR buffer.
+ * It will not have the "user." prefix, so prepend it.
+ * Lastly, check for nul characters in the name.
+ */
+static int
+nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
+{
+	DECODE_HEAD;
+	char *name, *sp, *dp;
+	u32 namelen, cnt;
+
+	READ_BUF(4);
+	namelen = be32_to_cpup(p++);
+
+	if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
+		return nfserr_nametoolong;
+
+	if (namelen == 0)
+		goto xdr_error;
+
+	READ_BUF(namelen);
+
+	name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
+	if (!name)
+		return nfserr_jukebox;
+
+	memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
+
+	/*
+	 * Copy the extended attribute name over while checking for 0
+	 * characters.
+	 */
+	sp = (char *)p;
+	dp = name + XATTR_USER_PREFIX_LEN;
+	cnt = namelen;
+
+	while (cnt-- > 0) {
+		if (*sp == '\0')
+			goto xdr_error;
+		*dp++ = *sp++;
+	}
+	*dp = '\0';
+
+	*namep = name;
+
+	DECODE_TAIL;
+}
+
+/*
+ * A GETXATTR op request comes without a length specifier. We just set the
+ * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
+ * channel reply size, allocate a buffer of that length and pass it to
+ * vfs_getxattr.
+ */
+static __be32
+nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp,
+		      struct nfsd4_getxattr *getxattr)
+{
+	int status;
+	u32 maxcount;
+
+	status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
+	if (status)
+		return status;
+
+	maxcount = svc_max_payload(argp->rqstp);
+	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	getxattr->getxa_buf = svcxdr_tmpalloc(argp, maxcount);
+	if (!getxattr->getxa_buf)
+		status = nfserr_jukebox;
+	getxattr->getxa_len = maxcount;
+
+	return status;
+}
+
+static __be32
+nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
+		      struct nfsd4_setxattr *setxattr)
+{
+	DECODE_HEAD;
+	u32 flags, maxcount, size;
+	struct kvec head;
+	struct page **pagelist;
+
+	READ_BUF(4);
+	flags = be32_to_cpup(p++);
+
+	if (flags > SETXATTR4_REPLACE)
+		return nfserr_inval;
+	setxattr->setxa_flags = flags;
+
+	status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
+	if (status)
+		return status;
+
+	maxcount = svc_max_payload(argp->rqstp);
+	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
+
+	READ_BUF(4);
+	size = be32_to_cpup(p++);
+	if (size > maxcount)
+		return nfserr_xattr2big;
+
+	setxattr->setxa_len = size;
+	if (size > 0) {
+		status = svcxdr_construct_vector(argp, &head, &pagelist, size);
+		if (status)
+			return status;
+
+		status = nfsd4_vbuf_from_stream(argp, &head, pagelist,
+		    &setxattr->setxa_buf, size);
+	}
+
+	DECODE_TAIL;
+}
+
+static __be32
+nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp,
+			struct nfsd4_listxattrs *listxattrs)
+{
+	DECODE_HEAD;
+	u32 maxcount;
+
+	READ_BUF(12);
+	p = xdr_decode_hyper(p, &listxattrs->lsxa_cookie);
+
+	/*
+	 * If the cookie  is too large to have even one user.x attribute
+	 * plus trailing '\0' left in a maximum size buffer, it's invalid.
+	 */
+	if (listxattrs->lsxa_cookie >=
+	    (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
+		return nfserr_badcookie;
+
+	maxcount = be32_to_cpup(p++);
+	if (maxcount < 8)
+		/* Always need at least 2 words (length and one character) */
+		return nfserr_inval;
+
+	maxcount = min(maxcount, svc_max_payload(argp->rqstp));
+	listxattrs->lsxa_maxcount = maxcount;
+
+	/*
+	 * Unfortunately, there is no interface to only list xattrs for
+	 * one prefix. So there is no good way to convert maxcount to
+	 * a maximum value to pass to vfs_listxattr, as we don't know
+	 * how many of the returned attributes will be user attributes.
+	 *
+	 * So, always ask vfs_listxattr for the maximum size, and encode
+	 * as many as possible.
+	 */
+	listxattrs->lsxa_buf = svcxdr_tmpalloc(argp, XATTR_LIST_MAX);
+	if (!listxattrs->lsxa_buf)
+		status = nfserr_jukebox;
+
+	DECODE_TAIL;
+}
+
+static __be32
+nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp,
+			 struct nfsd4_removexattr *removexattr)
+{
+	return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
+}
+
 static __be32
 nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
 {
@@ -1975,6 +2193,11 @@ static const nfsd4_dec nfsd4_dec_ops[] = {
 	[OP_SEEK]		= (nfsd4_dec)nfsd4_decode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_dec)nfsd4_decode_notsupp,
 	[OP_CLONE]		= (nfsd4_dec)nfsd4_decode_clone,
+	/* RFC 8276 extended atributes operations */
+	[OP_GETXATTR]		= (nfsd4_dec)nfsd4_decode_getxattr,
+	[OP_SETXATTR]		= (nfsd4_dec)nfsd4_decode_setxattr,
+	[OP_LISTXATTRS]		= (nfsd4_dec)nfsd4_decode_listxattrs,
+	[OP_REMOVEXATTR]	= (nfsd4_dec)nfsd4_decode_removexattr,
 };
 
 static inline bool
@@ -4458,6 +4681,225 @@ nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *p)
 	return nfserr;
 }
 
+/*
+ * Encode kmalloc-ed buffer in to XDR stream.
+ */
+static int
+nfsd4_vbuf_to_stream(struct xdr_stream *xdr, char *buf, u32 buflen)
+{
+	u32 cplen;
+	__be32 *p;
+
+	cplen = min_t(unsigned long, buflen,
+		      ((void *)xdr->end - (void *)xdr->p));
+	p = xdr_reserve_space(xdr, cplen);
+	if (!p)
+		return nfserr_resource;
+
+	memcpy(p, buf, cplen);
+	buf += cplen;
+	buflen -= cplen;
+
+	while (buflen) {
+		cplen = min_t(u32, buflen, PAGE_SIZE);
+		p = xdr_reserve_space(xdr, cplen);
+		if (!p)
+			return nfserr_resource;
+
+		memcpy(p, buf, cplen);
+
+		if (cplen < PAGE_SIZE) {
+			/*
+			 * We're done, with a length that wasn't page
+			 * aligned, so possibly not word aligned. Pad
+			 * any trailing bytes with 0.
+			 */
+			xdr_encode_opaque_fixed(p, NULL, cplen);
+			break;
+		}
+
+		buflen -= PAGE_SIZE;
+		buf += PAGE_SIZE;
+	}
+
+	return 0;
+}
+
+static __be32
+nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
+		      struct nfsd4_getxattr *getxattr)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 4);
+	if (!p)
+		return nfserr_resource;
+
+	*p = cpu_to_be32(getxattr->getxa_len);
+
+	if (getxattr->getxa_len == 0)
+		return 0;
+
+	return nfsd4_vbuf_to_stream(xdr, getxattr->getxa_buf,
+				    getxattr->getxa_len);
+}
+
+static __be32
+nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
+		      struct nfsd4_setxattr *setxattr)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 20);
+	if (!p)
+		return nfserr_resource;
+
+	encode_cinfo(p, &setxattr->setxa_cinfo);
+
+	return 0;
+}
+
+/*
+ * See if there are cookie values that can be rejected outright.
+ */
+static int
+nfsd4_listxattr_validate_cookie(struct nfsd4_listxattrs *listxattrs,
+				u32 *offsetp)
+{
+	u64 cookie = listxattrs->lsxa_cookie;
+
+	/*
+	 * If the cookie is larger than the maximum number we can fit
+	 * in either the buffer we just got back from vfs_listxattr, or,
+	 * XDR-encoded, in the return buffer, it's invalid.
+	 */
+	if (cookie > (listxattrs->lsxa_len) / (XATTR_USER_PREFIX_LEN + 2))
+		return nfserr_badcookie;
+
+	if (cookie > (listxattrs->lsxa_maxcount /
+		      (XDR_QUADLEN(XATTR_USER_PREFIX_LEN + 2) + 4)))
+		return nfserr_badcookie;
+
+	*offsetp = (u32)cookie;
+	return 0;
+}
+
+static __be32
+nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
+			struct nfsd4_listxattrs *listxattrs)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	u32 cookie_offset, count_offset, eof;
+	u32 left, xdrleft, slen, count;
+	u32 xdrlen, offset;
+	u64 cookie;
+	char *sp;
+	int status;
+	__be32 *p;
+	u32 nuser;
+
+	eof = 1;
+
+	status = nfsd4_listxattr_validate_cookie(listxattrs, &offset);
+	if (status)
+		return status;
+
+	/*
+	 * Reserve space for the cookie and the name array count. Record
+	 * the offsets to save them later.
+	 */
+	cookie_offset = xdr->buf->len;
+	count_offset = cookie_offset + 8;
+	p = xdr_reserve_space(xdr, 12);
+	if (!p)
+		return nfserr_resource;
+
+	count = 0;
+	left = listxattrs->lsxa_len;
+	sp = listxattrs->lsxa_buf;
+	nuser = 0;
+
+	xdrleft = listxattrs->lsxa_maxcount;
+
+	while (left > 0 && xdrleft > 0) {
+		slen = strlen(sp);
+
+		/*
+		 * Check if this a user. attribute, skip it if not.
+		 */
+		if (strncmp(sp, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
+			goto contloop;
+
+		slen -= XATTR_USER_PREFIX_LEN;
+		xdrlen = 4 + ((slen + 3) & ~3);
+		if (xdrlen > xdrleft) {
+			if (count == 0) {
+				/*
+				 * Can't even fit the first attribute name.
+				 */
+				return nfserr_toosmall;
+			}
+			eof = 0;
+			goto wreof;
+		}
+
+		left -= XATTR_USER_PREFIX_LEN;
+		sp += XATTR_USER_PREFIX_LEN;
+		if (nuser++ < offset)
+			goto contloop;
+
+
+		p = xdr_reserve_space(xdr, xdrlen);
+		if (!p)
+			return nfserr_resource;
+
+		p = xdr_encode_opaque(p, sp, slen);
+
+		xdrleft -= xdrlen;
+		count++;
+contloop:
+		sp += slen + 1;
+		left -= slen + 1;
+	}
+
+	/*
+	 * If there were user attributes to copy, but we didn't copy
+	 * any, the offset was too large (e.g. the cookie was invalid).
+	 */
+	if (nuser > 0 && count == 0)
+		return nfserr_badcookie;
+
+wreof:
+	p = xdr_reserve_space(xdr, 4);
+	if (!p)
+		return nfserr_resource;
+	*p = cpu_to_be32(eof);
+
+	cookie = offset + count;
+
+	write_bytes_to_xdr_buf(xdr->buf, cookie_offset, &cookie, 8);
+	count = htonl(count);
+	write_bytes_to_xdr_buf(xdr->buf, count_offset, &count, 4);
+	return 0;
+}
+
+static __be32
+nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
+			 struct nfsd4_removexattr *removexattr)
+{
+	struct xdr_stream *xdr = &resp->xdr;
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 20);
+	if (!p)
+		return nfserr_resource;
+
+	p = encode_cinfo(p, &removexattr->rmxa_cinfo);
+	return 0;
+}
+
 typedef __be32(* nfsd4_enc)(struct nfsd4_compoundres *, __be32, void *);
 
 /*
@@ -4547,6 +4989,12 @@ static const nfsd4_enc nfsd4_enc_ops[] = {
 	[OP_SEEK]		= (nfsd4_enc)nfsd4_encode_seek,
 	[OP_WRITE_SAME]		= (nfsd4_enc)nfsd4_encode_noop,
 	[OP_CLONE]		= (nfsd4_enc)nfsd4_encode_noop,
+
+	/* RFC 8276 extended atributes operations */
+	[OP_GETXATTR]		= (nfsd4_enc)nfsd4_encode_getxattr,
+	[OP_SETXATTR]		= (nfsd4_enc)nfsd4_encode_setxattr,
+	[OP_LISTXATTRS]		= (nfsd4_enc)nfsd4_encode_listxattrs,
+	[OP_REMOVEXATTR]	= (nfsd4_enc)nfsd4_encode_removexattr,
 };
 
 /*
-- 
2.16.6

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[kbuild test robot]

Hi Frank,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on nfsd/nfsd-next]
[also build test WARNING on nfs/linux-next linus/master v5.6-rc5 next-20200312]
[cannot apply to cel/for-next]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Frank-van-der-Linden/server-side-user-xattr-support-RFC-8276/20200312-064928
base:   git://linux-nfs.org/~bfields/linux.git nfsd-next
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.1-174-g094d5a94-dirty
        make ARCH=x86_64 allmodconfig
        make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)

   fs/nfsd/nfs4xdr.c:1860:16: sparse: sparse: incorrect type in assignment (different base types) @@    expected int status @@    got restricted __int status @@
   fs/nfsd/nfs4xdr.c:1860:16: sparse:    expected int status
   fs/nfsd/nfs4xdr.c:1860:16: sparse:    got restricted __be32
   fs/nfsd/nfs4xdr.c:1862:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got be32 @@
   fs/nfsd/nfs4xdr.c:1862:24: sparse:    expected restricted __be32
   fs/nfsd/nfs4xdr.c:1862:24: sparse:    got int status
>> fs/nfsd/nfs4xdr.c:1913:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [usertypint @@
>> fs/nfsd/nfs4xdr.c:1913:24: sparse:    expected int
>> fs/nfsd/nfs4xdr.c:1913:24: sparse:    got restricted __be32 [usertype]
   fs/nfsd/nfs4xdr.c:1949:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [usertypint @@
   fs/nfsd/nfs4xdr.c:1949:24: sparse:    expected int
   fs/nfsd/nfs4xdr.c:1949:24: sparse:    got restricted __be32 [usertype]
   fs/nfsd/nfs4xdr.c:1958:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [usertypint @@
   fs/nfsd/nfs4xdr.c:1958:24: sparse:    expected int
   fs/nfsd/nfs4xdr.c:1958:24: sparse:    got restricted __be32 [usertype]
>> fs/nfsd/nfs4xdr.c:1979:9: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [assigned] [usertypint @@
   fs/nfsd/nfs4xdr.c:1979:9: sparse:    expected int
>> fs/nfsd/nfs4xdr.c:1979:9: sparse:    got restricted __be32 [assigned] [usertype] status
>> fs/nfsd/nfs4xdr.c:1997:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got stricted __be32 @@
   fs/nfsd/nfs4xdr.c:1997:24: sparse:    expected restricted __be32
>> fs/nfsd/nfs4xdr.c:1997:24: sparse:    got int [assigned] status
>> fs/nfsd/nfs4xdr.c:2004:24: sparse: sparse: incorrect type in assignment (different base types) @@    expected int [assigned] status @@    got restricted __bint [assigned] status @@
>> fs/nfsd/nfs4xdr.c:2004:24: sparse:    expected int [assigned] status
   fs/nfsd/nfs4xdr.c:2004:24: sparse:    got restricted __be32 [usertype]
   fs/nfsd/nfs4xdr.c:2007:16: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got stricted __be32 @@
   fs/nfsd/nfs4xdr.c:2007:16: sparse:    expected restricted __be32
   fs/nfsd/nfs4xdr.c:2007:16: sparse:    got int [assigned] status
>> fs/nfsd/nfs4xdr.c:2026:16: sparse: sparse: incorrect type in assignment (different base types) @@    expected restricted __be32 [usertype] status @@    got e] status @@
>> fs/nfsd/nfs4xdr.c:2026:16: sparse:    expected restricted __be32 [usertype] status
>> fs/nfsd/nfs4xdr.c:2026:16: sparse:    got int
>> fs/nfsd/nfs4xdr.c:2044:24: sparse: sparse: incorrect type in assignment (different base types) @@    expected restricted __be32 [assigned] [usertype] status @@    got e] status @@
>> fs/nfsd/nfs4xdr.c:2044:24: sparse:    expected restricted __be32 [assigned] [usertype] status
   fs/nfsd/nfs4xdr.c:2044:24: sparse:    got int
>> fs/nfsd/nfs4xdr.c:2097:39: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got e32 @@
   fs/nfsd/nfs4xdr.c:2097:39: sparse:    expected restricted __be32
   fs/nfsd/nfs4xdr.c:2097:39: sparse:    got int
   fs/nfsd/nfs4xdr.c:4698:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [usertypint @@
   fs/nfsd/nfs4xdr.c:4698:24: sparse:    expected int
   fs/nfsd/nfs4xdr.c:4698:24: sparse:    got restricted __be32 [usertype]
   fs/nfsd/nfs4xdr.c:4708:32: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [usertypint @@
   fs/nfsd/nfs4xdr.c:4708:32: sparse:    expected int
   fs/nfsd/nfs4xdr.c:4708:32: sparse:    got restricted __be32 [usertype]
   fs/nfsd/nfs4xdr.c:4745:36: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got e32 @@
   fs/nfsd/nfs4xdr.c:4745:36: sparse:    expected restricted __be32
   fs/nfsd/nfs4xdr.c:4745:36: sparse:    got int
   fs/nfsd/nfs4xdr.c:4780:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [usertypint @@
   fs/nfsd/nfs4xdr.c:4780:24: sparse:    expected int
   fs/nfsd/nfs4xdr.c:4780:24: sparse:    got restricted __be32 [usertype]
   fs/nfsd/nfs4xdr.c:4784:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected int @@    got restricted __be32 [usertypint @@
   fs/nfsd/nfs4xdr.c:4784:24: sparse:    expected int
   fs/nfsd/nfs4xdr.c:4784:24: sparse:    got restricted __be32 [usertype]
   fs/nfsd/nfs4xdr.c:4808:24: sparse: sparse: incorrect type in return expression (different base types) @@    expected restricted __be32 @@    got stricted __be32 @@
   fs/nfsd/nfs4xdr.c:4808:24: sparse:    expected restricted __be32
   fs/nfsd/nfs4xdr.c:4808:24: sparse:    got int [assigned] status
>> fs/nfsd/nfs4xdr.c:4884:15: sparse: sparse: incorrect type in assignment (different base types) @@    expected unsigned int [assigned] [usertype] count @@    got ed int [assigned] [usertype] count @@
>> fs/nfsd/nfs4xdr.c:4884:15: sparse:    expected unsigned int [assigned] [usertype] count
   fs/nfsd/nfs4xdr.c:4884:15: sparse:    got restricted __be32 [usertype]

vim +1913 fs/nfsd/nfs4xdr.c

  1881	
  1882	/*
  1883	 * XDR data that is more than PAGE_SIZE in size is normally part of a
  1884	 * read or write. However, the size of extended attributes is limited
  1885	 * by the maximum request size, and then further limited by the underlying
  1886	 * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
  1887	 * is 64k). Since there is no kvec- or page-based interface to xattrs,
  1888	 * and we're not dealing with contiguous pages, we need to do some copying.
  1889	 */
  1890	
  1891	/*
  1892	 * Decode int to buffer. Uses head and pages constructed by
  1893	 * svcxdr_construct_vector.
  1894	 */
  1895	static int
  1896	nfsd4_vbuf_from_stream(struct nfsd4_compoundargs *argp, struct kvec *head,
  1897			       struct page **pages, char **bufp, u32 buflen)
  1898	{
  1899		char *tmp, *dp;
  1900		u32 len;
  1901	
  1902		if (buflen <= head->iov_len) {
  1903			/*
  1904			 * We're in luck, the head has enough space. Just return
  1905			 * the head, no need for copying.
  1906			 */
  1907			*bufp = head->iov_base;
  1908			return 0;
  1909		}
  1910	
  1911		tmp = svcxdr_tmpalloc(argp, buflen);
  1912		if (tmp == NULL)
> 1913			return nfserr_jukebox;
  1914	
  1915		dp = tmp;
  1916		memcpy(dp, head->iov_base, head->iov_len);
  1917		buflen -= head->iov_len;
  1918		dp += head->iov_len;
  1919	
  1920		while (buflen > 0) {
  1921			len = min_t(u32, buflen, PAGE_SIZE);
  1922			memcpy(dp, page_address(*pages), len);
  1923	
  1924			buflen -= len;
  1925			dp += len;
  1926			pages++;
  1927		}
  1928	
  1929		*bufp = tmp;
  1930		return 0;
  1931	}
  1932	
  1933	/*
  1934	 * Get a user extended attribute name from the XDR buffer.
  1935	 * It will not have the "user." prefix, so prepend it.
  1936	 * Lastly, check for nul characters in the name.
  1937	 */
  1938	static int
  1939	nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
  1940	{
  1941		DECODE_HEAD;
  1942		char *name, *sp, *dp;
  1943		u32 namelen, cnt;
  1944	
  1945		READ_BUF(4);
  1946		namelen = be32_to_cpup(p++);
  1947	
  1948		if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
  1949			return nfserr_nametoolong;
  1950	
  1951		if (namelen == 0)
  1952			goto xdr_error;
  1953	
  1954		READ_BUF(namelen);
  1955	
  1956		name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
  1957		if (!name)
  1958			return nfserr_jukebox;
  1959	
  1960		memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
  1961	
  1962		/*
  1963		 * Copy the extended attribute name over while checking for 0
  1964		 * characters.
  1965		 */
  1966		sp = (char *)p;
  1967		dp = name + XATTR_USER_PREFIX_LEN;
  1968		cnt = namelen;
  1969	
  1970		while (cnt-- > 0) {
  1971			if (*sp == '\0')
  1972				goto xdr_error;
  1973			*dp++ = *sp++;
  1974		}
  1975		*dp = '\0';
  1976	
  1977		*namep = name;
  1978	
> 1979		DECODE_TAIL;
  1980	}
  1981	
  1982	/*
  1983	 * A GETXATTR op request comes without a length specifier. We just set the
  1984	 * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
  1985	 * channel reply size, allocate a buffer of that length and pass it to
  1986	 * vfs_getxattr.
  1987	 */
  1988	static __be32
  1989	nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp,
  1990			      struct nfsd4_getxattr *getxattr)
  1991	{
  1992		int status;
  1993		u32 maxcount;
  1994	
  1995		status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
  1996		if (status)
> 1997			return status;
  1998	
  1999		maxcount = svc_max_payload(argp->rqstp);
  2000		maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
  2001	
  2002		getxattr->getxa_buf = svcxdr_tmpalloc(argp, maxcount);
  2003		if (!getxattr->getxa_buf)
> 2004			status = nfserr_jukebox;
  2005		getxattr->getxa_len = maxcount;
  2006	
  2007		return status;
  2008	}
  2009	
  2010	static __be32
  2011	nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
  2012			      struct nfsd4_setxattr *setxattr)
  2013	{
  2014		DECODE_HEAD;
  2015		u32 flags, maxcount, size;
  2016		struct kvec head;
  2017		struct page **pagelist;
  2018	
  2019		READ_BUF(4);
  2020		flags = be32_to_cpup(p++);
  2021	
  2022		if (flags > SETXATTR4_REPLACE)
  2023			return nfserr_inval;
  2024		setxattr->setxa_flags = flags;
  2025	
> 2026		status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
  2027		if (status)
  2028			return status;
  2029	
  2030		maxcount = svc_max_payload(argp->rqstp);
  2031		maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
  2032	
  2033		READ_BUF(4);
  2034		size = be32_to_cpup(p++);
  2035		if (size > maxcount)
  2036			return nfserr_xattr2big;
  2037	
  2038		setxattr->setxa_len = size;
  2039		if (size > 0) {
  2040			status = svcxdr_construct_vector(argp, &head, &pagelist, size);
  2041			if (status)
  2042				return status;
  2043	
> 2044			status = nfsd4_vbuf_from_stream(argp, &head, pagelist,
  2045			    &setxattr->setxa_buf, size);
  2046		}
  2047	
  2048		DECODE_TAIL;
  2049	}
  2050	
  2051	static __be32
  2052	nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp,
  2053				struct nfsd4_listxattrs *listxattrs)
  2054	{
  2055		DECODE_HEAD;
  2056		u32 maxcount;
  2057	
  2058		READ_BUF(12);
  2059		p = xdr_decode_hyper(p, &listxattrs->lsxa_cookie);
  2060	
  2061		/*
  2062		 * If the cookie  is too large to have even one user.x attribute
  2063		 * plus trailing '\0' left in a maximum size buffer, it's invalid.
  2064		 */
  2065		if (listxattrs->lsxa_cookie >=
  2066		    (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
  2067			return nfserr_badcookie;
  2068	
  2069		maxcount = be32_to_cpup(p++);
  2070		if (maxcount < 8)
  2071			/* Always need at least 2 words (length and one character) */
  2072			return nfserr_inval;
  2073	
  2074		maxcount = min(maxcount, svc_max_payload(argp->rqstp));
  2075		listxattrs->lsxa_maxcount = maxcount;
  2076	
  2077		/*
  2078		 * Unfortunately, there is no interface to only list xattrs for
  2079		 * one prefix. So there is no good way to convert maxcount to
  2080		 * a maximum value to pass to vfs_listxattr, as we don't know
  2081		 * how many of the returned attributes will be user attributes.
  2082		 *
  2083		 * So, always ask vfs_listxattr for the maximum size, and encode
  2084		 * as many as possible.
  2085		 */
  2086		listxattrs->lsxa_buf = svcxdr_tmpalloc(argp, XATTR_LIST_MAX);
  2087		if (!listxattrs->lsxa_buf)
  2088			status = nfserr_jukebox;
  2089	
  2090		DECODE_TAIL;
  2091	}
  2092	
  2093	static __be32
  2094	nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp,
  2095				 struct nfsd4_removexattr *removexattr)
  2096	{
> 2097		return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
  2098	}
  2099	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Chuck Lever]

> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> Add functions to calculate the reply size for the user extended attribute
> operations, and implement the XDR encode / decode logic for these
> operations.
> 
> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/nfsd/nfs4proc.c |  36 +++++
> fs/nfsd/nfs4xdr.c  | 448 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 484 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index a76b9025a357..44d488bdebd9 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -2778,6 +2778,42 @@ static inline u32 nfsd4_seek_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
> 	return (op_encode_hdr_size + 3) * sizeof(__be32);
> }
> 
> +static inline u32 nfsd4_getxattr_rsize(struct svc_rqst *rqstp,
> +				       struct nfsd4_op *op)
> +{
> +	u32 maxcount, rlen;
> +
> +	maxcount = svc_max_payload(rqstp);
> +	rlen = min_t(u32, XATTR_SIZE_MAX, maxcount);
> +
> +	return (op_encode_hdr_size + 1 + XDR_QUADLEN(rlen)) * sizeof(__be32);

These should be added in the same patch that adds OP_GETXATTR and friends.

Also, Trond recently added xdr_align_size which I prefer over the
use of XDR_QUADLEN in new code.


> +}
> +
> +static inline u32 nfsd4_setxattr_rsize(struct svc_rqst *rqstp,
> +				       struct nfsd4_op *op)
> +{
> +	return (op_encode_hdr_size + op_encode_change_info_maxsz)
> +		* sizeof(__be32);
> +}
> +static inline u32 nfsd4_listxattrs_rsize(struct svc_rqst *rqstp,
> +					 struct nfsd4_op *op)
> +{
> +	u32 maxcount, rlen;
> +
> +	maxcount = svc_max_payload(rqstp);
> +	rlen = min(op->u.listxattrs.lsxa_maxcount, maxcount);
> +
> +	return (op_encode_hdr_size + 4 + XDR_QUADLEN(rlen)) * sizeof(__be32);
> +}
> +
> +static inline u32 nfsd4_removexattr_rsize(struct svc_rqst *rqstp,
> +					  struct nfsd4_op *op)
> +{
> +	return (op_encode_hdr_size + op_encode_change_info_maxsz)
> +		* sizeof(__be32);
> +}
> +
> +
> static const struct nfsd4_operation nfsd4_ops[LAST_NFS4_OP + 1] = {
> 	[OP_ACCESS] = {
> 		.op_func = nfsd4_access,
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index b12d7ac6f52c..41c8b95ca1c5 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -1879,6 +1879,224 @@ nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
> 	DECODE_TAIL;
> }
> 
> +/*
> + * XDR data that is more than PAGE_SIZE in size is normally part of a
> + * read or write. However, the size of extended attributes is limited
> + * by the maximum request size, and then further limited by the underlying
> + * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
> + * is 64k). Since there is no kvec- or page-based interface to xattrs,
> + * and we're not dealing with contiguous pages, we need to do some copying.
> + */
> +
> +/*
> + * Decode int to buffer. Uses head and pages constructed by
> + * svcxdr_construct_vector.
> + */
> +static int
> +nfsd4_vbuf_from_stream(struct nfsd4_compoundargs *argp, struct kvec *head,
> +		       struct page **pages, char **bufp, u32 buflen)
> +{
> +	char *tmp, *dp;
> +	u32 len;
> +
> +	if (buflen <= head->iov_len) {
> +		/*
> +		 * We're in luck, the head has enough space. Just return
> +		 * the head, no need for copying.
> +		 */
> +		*bufp = head->iov_base;
> +		return 0;
> +	}
> +
> +	tmp = svcxdr_tmpalloc(argp, buflen);
> +	if (tmp == NULL)
> +		return nfserr_jukebox;
> +
> +	dp = tmp;
> +	memcpy(dp, head->iov_base, head->iov_len);
> +	buflen -= head->iov_len;
> +	dp += head->iov_len;
> +
> +	while (buflen > 0) {
> +		len = min_t(u32, buflen, PAGE_SIZE);
> +		memcpy(dp, page_address(*pages), len);
> +
> +		buflen -= len;
> +		dp += len;
> +		pages++;
> +	}
> +
> +	*bufp = tmp;
> +	return 0;
> +}
> +
> +/*
> + * Get a user extended attribute name from the XDR buffer.
> + * It will not have the "user." prefix, so prepend it.
> + * Lastly, check for nul characters in the name.
> + */
> +static int
> +nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
> +{
> +	DECODE_HEAD;
> +	char *name, *sp, *dp;
> +	u32 namelen, cnt;
> +
> +	READ_BUF(4);
> +	namelen = be32_to_cpup(p++);
> +
> +	if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
> +		return nfserr_nametoolong;
> +
> +	if (namelen == 0)
> +		goto xdr_error;
> +
> +	READ_BUF(namelen);
> +
> +	name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
> +	if (!name)
> +		return nfserr_jukebox;
> +
> +	memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
> +
> +	/*
> +	 * Copy the extended attribute name over while checking for 0
> +	 * characters.
> +	 */
> +	sp = (char *)p;
> +	dp = name + XATTR_USER_PREFIX_LEN;
> +	cnt = namelen;
> +
> +	while (cnt-- > 0) {
> +		if (*sp == '\0')
> +			goto xdr_error;
> +		*dp++ = *sp++;
> +	}
> +	*dp = '\0';
> +
> +	*namep = name;
> +
> +	DECODE_TAIL;
> +}
> +
> +/*
> + * A GETXATTR op request comes without a length specifier. We just set the
> + * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
> + * channel reply size, allocate a buffer of that length and pass it to
> + * vfs_getxattr.
> + */
> +static __be32
> +nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp,
> +		      struct nfsd4_getxattr *getxattr)
> +{
> +	int status;
> +	u32 maxcount;
> +
> +	status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
> +	if (status)
> +		return status;
> +
> +	maxcount = svc_max_payload(argp->rqstp);
> +	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
> +
> +	getxattr->getxa_buf = svcxdr_tmpalloc(argp, maxcount);
> +	if (!getxattr->getxa_buf)
> +		status = nfserr_jukebox;
> +	getxattr->getxa_len = maxcount;
> +
> +	return status;
> +}
> +
> +static __be32
> +nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
> +		      struct nfsd4_setxattr *setxattr)
> +{
> +	DECODE_HEAD;
> +	u32 flags, maxcount, size;
> +	struct kvec head;
> +	struct page **pagelist;
> +
> +	READ_BUF(4);
> +	flags = be32_to_cpup(p++);
> +
> +	if (flags > SETXATTR4_REPLACE)
> +		return nfserr_inval;
> +	setxattr->setxa_flags = flags;
> +
> +	status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
> +	if (status)
> +		return status;
> +
> +	maxcount = svc_max_payload(argp->rqstp);
> +	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
> +
> +	READ_BUF(4);
> +	size = be32_to_cpup(p++);
> +	if (size > maxcount)
> +		return nfserr_xattr2big;
> +
> +	setxattr->setxa_len = size;
> +	if (size > 0) {
> +		status = svcxdr_construct_vector(argp, &head, &pagelist, size);
> +		if (status)
> +			return status;
> +
> +		status = nfsd4_vbuf_from_stream(argp, &head, pagelist,
> +		    &setxattr->setxa_buf, size);
> +	}
> +
> +	DECODE_TAIL;
> +}
> +
> +static __be32
> +nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp,
> +			struct nfsd4_listxattrs *listxattrs)
> +{
> +	DECODE_HEAD;
> +	u32 maxcount;
> +
> +	READ_BUF(12);
> +	p = xdr_decode_hyper(p, &listxattrs->lsxa_cookie);
> +
> +	/*
> +	 * If the cookie  is too large to have even one user.x attribute
> +	 * plus trailing '\0' left in a maximum size buffer, it's invalid.
> +	 */
> +	if (listxattrs->lsxa_cookie >=
> +	    (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
> +		return nfserr_badcookie;
> +
> +	maxcount = be32_to_cpup(p++);
> +	if (maxcount < 8)
> +		/* Always need at least 2 words (length and one character) */
> +		return nfserr_inval;
> +
> +	maxcount = min(maxcount, svc_max_payload(argp->rqstp));
> +	listxattrs->lsxa_maxcount = maxcount;
> +
> +	/*
> +	 * Unfortunately, there is no interface to only list xattrs for
> +	 * one prefix. So there is no good way to convert maxcount to
> +	 * a maximum value to pass to vfs_listxattr, as we don't know
> +	 * how many of the returned attributes will be user attributes.
> +	 *
> +	 * So, always ask vfs_listxattr for the maximum size, and encode
> +	 * as many as possible.
> +	 */

Well, this approach worries me a little bit. Wouldn't it be better if the
VFS provided the APIs? Review by linux-fsdevel might help here.


> +	listxattrs->lsxa_buf = svcxdr_tmpalloc(argp, XATTR_LIST_MAX);
> +	if (!listxattrs->lsxa_buf)
> +		status = nfserr_jukebox;
> +
> +	DECODE_TAIL;
> +}
> +
> +static __be32
> +nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp,
> +			 struct nfsd4_removexattr *removexattr)
> +{
> +	return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
> +}
> +
> static __be32
> nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
> {
> @@ -1975,6 +2193,11 @@ static const nfsd4_dec nfsd4_dec_ops[] = {
> 	[OP_SEEK]		= (nfsd4_dec)nfsd4_decode_seek,
> 	[OP_WRITE_SAME]		= (nfsd4_dec)nfsd4_decode_notsupp,
> 	[OP_CLONE]		= (nfsd4_dec)nfsd4_decode_clone,
> +	/* RFC 8276 extended atributes operations */
> +	[OP_GETXATTR]		= (nfsd4_dec)nfsd4_decode_getxattr,
> +	[OP_SETXATTR]		= (nfsd4_dec)nfsd4_decode_setxattr,
> +	[OP_LISTXATTRS]		= (nfsd4_dec)nfsd4_decode_listxattrs,
> +	[OP_REMOVEXATTR]	= (nfsd4_dec)nfsd4_decode_removexattr,
> };
> 
> static inline bool
> @@ -4458,6 +4681,225 @@ nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *p)
> 	return nfserr;
> }
> 
> +/*
> + * Encode kmalloc-ed buffer in to XDR stream.
> + */
> +static int
> +nfsd4_vbuf_to_stream(struct xdr_stream *xdr, char *buf, u32 buflen)
> +{
> +	u32 cplen;
> +	__be32 *p;
> +
> +	cplen = min_t(unsigned long, buflen,
> +		      ((void *)xdr->end - (void *)xdr->p));
> +	p = xdr_reserve_space(xdr, cplen);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	memcpy(p, buf, cplen);
> +	buf += cplen;
> +	buflen -= cplen;
> +
> +	while (buflen) {
> +		cplen = min_t(u32, buflen, PAGE_SIZE);
> +		p = xdr_reserve_space(xdr, cplen);
> +		if (!p)
> +			return nfserr_resource;
> +
> +		memcpy(p, buf, cplen);
> +
> +		if (cplen < PAGE_SIZE) {
> +			/*
> +			 * We're done, with a length that wasn't page
> +			 * aligned, so possibly not word aligned. Pad
> +			 * any trailing bytes with 0.
> +			 */
> +			xdr_encode_opaque_fixed(p, NULL, cplen);
> +			break;
> +		}
> +
> +		buflen -= PAGE_SIZE;
> +		buf += PAGE_SIZE;
> +	}
> +
> +	return 0;
> +}
> +
> +static __be32
> +nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
> +		      struct nfsd4_getxattr *getxattr)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	__be32 *p;
> +
> +	p = xdr_reserve_space(xdr, 4);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	*p = cpu_to_be32(getxattr->getxa_len);
> +
> +	if (getxattr->getxa_len == 0)
> +		return 0;
> +
> +	return nfsd4_vbuf_to_stream(xdr, getxattr->getxa_buf,
> +				    getxattr->getxa_len);
> +}
> +
> +static __be32
> +nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
> +		      struct nfsd4_setxattr *setxattr)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	__be32 *p;
> +
> +	p = xdr_reserve_space(xdr, 20);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	encode_cinfo(p, &setxattr->setxa_cinfo);
> +
> +	return 0;
> +}
> +
> +/*
> + * See if there are cookie values that can be rejected outright.
> + */
> +static int
> +nfsd4_listxattr_validate_cookie(struct nfsd4_listxattrs *listxattrs,
> +				u32 *offsetp)
> +{
> +	u64 cookie = listxattrs->lsxa_cookie;
> +
> +	/*
> +	 * If the cookie is larger than the maximum number we can fit
> +	 * in either the buffer we just got back from vfs_listxattr, or,
> +	 * XDR-encoded, in the return buffer, it's invalid.
> +	 */
> +	if (cookie > (listxattrs->lsxa_len) / (XATTR_USER_PREFIX_LEN + 2))
> +		return nfserr_badcookie;
> +
> +	if (cookie > (listxattrs->lsxa_maxcount /
> +		      (XDR_QUADLEN(XATTR_USER_PREFIX_LEN + 2) + 4)))
> +		return nfserr_badcookie;
> +
> +	*offsetp = (u32)cookie;
> +	return 0;
> +}
> +
> +static __be32
> +nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
> +			struct nfsd4_listxattrs *listxattrs)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	u32 cookie_offset, count_offset, eof;
> +	u32 left, xdrleft, slen, count;
> +	u32 xdrlen, offset;
> +	u64 cookie;
> +	char *sp;
> +	int status;
> +	__be32 *p;
> +	u32 nuser;
> +
> +	eof = 1;
> +
> +	status = nfsd4_listxattr_validate_cookie(listxattrs, &offset);
> +	if (status)
> +		return status;
> +
> +	/*
> +	 * Reserve space for the cookie and the name array count. Record
> +	 * the offsets to save them later.
> +	 */
> +	cookie_offset = xdr->buf->len;
> +	count_offset = cookie_offset + 8;
> +	p = xdr_reserve_space(xdr, 12);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	count = 0;
> +	left = listxattrs->lsxa_len;
> +	sp = listxattrs->lsxa_buf;
> +	nuser = 0;
> +
> +	xdrleft = listxattrs->lsxa_maxcount;
> +
> +	while (left > 0 && xdrleft > 0) {
> +		slen = strlen(sp);
> +
> +		/*
> +		 * Check if this a user. attribute, skip it if not.
> +		 */
> +		if (strncmp(sp, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
> +			goto contloop;
> +
> +		slen -= XATTR_USER_PREFIX_LEN;
> +		xdrlen = 4 + ((slen + 3) & ~3);
> +		if (xdrlen > xdrleft) {
> +			if (count == 0) {
> +				/*
> +				 * Can't even fit the first attribute name.
> +				 */
> +				return nfserr_toosmall;
> +			}
> +			eof = 0;
> +			goto wreof;
> +		}
> +
> +		left -= XATTR_USER_PREFIX_LEN;
> +		sp += XATTR_USER_PREFIX_LEN;
> +		if (nuser++ < offset)
> +			goto contloop;
> +
> +
> +		p = xdr_reserve_space(xdr, xdrlen);
> +		if (!p)
> +			return nfserr_resource;
> +
> +		p = xdr_encode_opaque(p, sp, slen);
> +
> +		xdrleft -= xdrlen;
> +		count++;
> +contloop:
> +		sp += slen + 1;
> +		left -= slen + 1;
> +	}
> +
> +	/*
> +	 * If there were user attributes to copy, but we didn't copy
> +	 * any, the offset was too large (e.g. the cookie was invalid).
> +	 */
> +	if (nuser > 0 && count == 0)
> +		return nfserr_badcookie;
> +
> +wreof:
> +	p = xdr_reserve_space(xdr, 4);
> +	if (!p)
> +		return nfserr_resource;
> +	*p = cpu_to_be32(eof);
> +
> +	cookie = offset + count;
> +
> +	write_bytes_to_xdr_buf(xdr->buf, cookie_offset, &cookie, 8);
> +	count = htonl(count);
> +	write_bytes_to_xdr_buf(xdr->buf, count_offset, &count, 4);
> +	return 0;
> +}
> +
> +static __be32
> +nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
> +			 struct nfsd4_removexattr *removexattr)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	__be32 *p;
> +
> +	p = xdr_reserve_space(xdr, 20);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	p = encode_cinfo(p, &removexattr->rmxa_cinfo);
> +	return 0;
> +}
> +
> typedef __be32(* nfsd4_enc)(struct nfsd4_compoundres *, __be32, void *);
> 
> /*
> @@ -4547,6 +4989,12 @@ static const nfsd4_enc nfsd4_enc_ops[] = {
> 	[OP_SEEK]		= (nfsd4_enc)nfsd4_encode_seek,
> 	[OP_WRITE_SAME]		= (nfsd4_enc)nfsd4_encode_noop,
> 	[OP_CLONE]		= (nfsd4_enc)nfsd4_encode_noop,
> +
> +	/* RFC 8276 extended atributes operations */
> +	[OP_GETXATTR]		= (nfsd4_enc)nfsd4_encode_getxattr,
> +	[OP_SETXATTR]		= (nfsd4_enc)nfsd4_encode_setxattr,
> +	[OP_LISTXATTRS]		= (nfsd4_enc)nfsd4_encode_listxattrs,
> +	[OP_REMOVEXATTR]	= (nfsd4_enc)nfsd4_encode_removexattr,
> };
> 
> /*
> -- 
> 2.16.6
> 

--
Chuck Lever

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Frank van der Linden]

On Thu, Mar 12, 2020 at 12:24:18PM -0400, Chuck Lever wrote:
> > +static inline u32 nfsd4_getxattr_rsize(struct svc_rqst *rqstp,
> > +                                    struct nfsd4_op *op)
> > +{
> > +     u32 maxcount, rlen;
> > +
> > +     maxcount = svc_max_payload(rqstp);
> > +     rlen = min_t(u32, XATTR_SIZE_MAX, maxcount);
> > +
> > +     return (op_encode_hdr_size + 1 + XDR_QUADLEN(rlen)) * sizeof(__be32);
> 
> These should be added in the same patch that adds OP_GETXATTR and friends.
> 
> Also, Trond recently added xdr_align_size which I prefer over the
> use of XDR_QUADLEN in new code.

Thanks, I've squashed together those patches for this and the other reasons
you pointed out.

As for XDR_QUADLEN: that returns the 32bit-word rounded up lenghth - in words.
xdr_aligned_size returns the 32bit-word rounded up length - in bytes.

So, the result would then look something like:

	return xdr_align_size((op_encode_hdr_size * 4) + 4 + rlen);

Is that what you're suggesting?

- Frank

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Chuck Lever]

> On Mar 19, 2020, at 6:13 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> On Thu, Mar 12, 2020 at 12:24:18PM -0400, Chuck Lever wrote:
>>> +static inline u32 nfsd4_getxattr_rsize(struct svc_rqst *rqstp,
>>> +                                    struct nfsd4_op *op)
>>> +{
>>> +     u32 maxcount, rlen;
>>> +
>>> +     maxcount = svc_max_payload(rqstp);
>>> +     rlen = min_t(u32, XATTR_SIZE_MAX, maxcount);
>>> +
>>> +     return (op_encode_hdr_size + 1 + XDR_QUADLEN(rlen)) * sizeof(__be32);
>> 
>> These should be added in the same patch that adds OP_GETXATTR and friends.
>> 
>> Also, Trond recently added xdr_align_size which I prefer over the
>> use of XDR_QUADLEN in new code.
> 
> Thanks, I've squashed together those patches for this and the other reasons
> you pointed out.
> 
> As for XDR_QUADLEN: that returns the 32bit-word rounded up lenghth - in words.
> xdr_aligned_size returns the 32bit-word rounded up length - in bytes.
> 
> So, the result would then look something like:
> 
> 	return xdr_align_size((op_encode_hdr_size * 4) + 4 + rlen);
> 
> Is that what you're suggesting?

Oops, you're right. When you want words, XDR_QUADLEN is correct. Never mind!


--
Chuck Lever

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Frank van der Linden]

On Thu, Mar 12, 2020 at 12:24:18PM -0400, Chuck Lever wrote:
> > On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> > +     /*
> > +      * Unfortunately, there is no interface to only list xattrs for
> > +      * one prefix. So there is no good way to convert maxcount to
> > +      * a maximum value to pass to vfs_listxattr, as we don't know
> > +      * how many of the returned attributes will be user attributes.
> > +      *
> > +      * So, always ask vfs_listxattr for the maximum size, and encode
> > +      * as many as possible.
> > +      */
> 
> Well, this approach worries me a little bit. Wouldn't it be better if the
> VFS provided the APIs? Review by linux-fsdevel might help here.

I missed this comment initially, sorry about the slow reply.

I'll copy this one to -fsdevel for v2.

It would require a modified or new entry point to all filesystems to
support this properly, so I didn't touch it. It's not a complex
task, it just would lead to quite a bit of code churn.

- Frank

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Chuck Lever]

> On Mar 25, 2020, at 7:44 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> On Thu, Mar 12, 2020 at 12:24:18PM -0400, Chuck Lever wrote:
>>> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
>>> +     /*
>>> +      * Unfortunately, there is no interface to only list xattrs for
>>> +      * one prefix. So there is no good way to convert maxcount to
>>> +      * a maximum value to pass to vfs_listxattr, as we don't know
>>> +      * how many of the returned attributes will be user attributes.
>>> +      *
>>> +      * So, always ask vfs_listxattr for the maximum size, and encode
>>> +      * as many as possible.
>>> +      */
>> 
>> Well, this approach worries me a little bit. Wouldn't it be better if the
>> VFS provided the APIs? Review by linux-fsdevel might help here.
> 
> I missed this comment initially, sorry about the slow reply.
> 
> I'll copy this one to -fsdevel for v2.
> 
> It would require a modified or new entry point to all filesystems to
> support this properly, so I didn't touch it. It's not a complex
> task, it just would lead to quite a bit of code churn.

Yep, I recognize it would be a substantial chunk of work. Passing
it by -fsdevel is the right thing to do, IMO. Thanks!


--
Chuck Lever

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Chuck Lever]

> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> Add functions to calculate the reply size for the user extended attribute
> operations, and implement the XDR encode / decode logic for these
> operations.
> 
> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/nfsd/nfs4proc.c |  36 +++++
> fs/nfsd/nfs4xdr.c  | 448 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 484 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index a76b9025a357..44d488bdebd9 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -2778,6 +2778,42 @@ static inline u32 nfsd4_seek_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
> 	return (op_encode_hdr_size + 3) * sizeof(__be32);
> }
> 
> +static inline u32 nfsd4_getxattr_rsize(struct svc_rqst *rqstp,
> +				       struct nfsd4_op *op)
> +{
> +	u32 maxcount, rlen;
> +
> +	maxcount = svc_max_payload(rqstp);
> +	rlen = min_t(u32, XATTR_SIZE_MAX, maxcount);
> +
> +	return (op_encode_hdr_size + 1 + XDR_QUADLEN(rlen)) * sizeof(__be32);
> +}
> +
> +static inline u32 nfsd4_setxattr_rsize(struct svc_rqst *rqstp,
> +				       struct nfsd4_op *op)
> +{
> +	return (op_encode_hdr_size + op_encode_change_info_maxsz)
> +		* sizeof(__be32);
> +}
> +static inline u32 nfsd4_listxattrs_rsize(struct svc_rqst *rqstp,
> +					 struct nfsd4_op *op)
> +{
> +	u32 maxcount, rlen;
> +
> +	maxcount = svc_max_payload(rqstp);
> +	rlen = min(op->u.listxattrs.lsxa_maxcount, maxcount);
> +
> +	return (op_encode_hdr_size + 4 + XDR_QUADLEN(rlen)) * sizeof(__be32);
> +}
> +
> +static inline u32 nfsd4_removexattr_rsize(struct svc_rqst *rqstp,
> +					  struct nfsd4_op *op)
> +{
> +	return (op_encode_hdr_size + op_encode_change_info_maxsz)
> +		* sizeof(__be32);
> +}
> +
> +
> static const struct nfsd4_operation nfsd4_ops[LAST_NFS4_OP + 1] = {
> 	[OP_ACCESS] = {
> 		.op_func = nfsd4_access,
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index b12d7ac6f52c..41c8b95ca1c5 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -1879,6 +1879,224 @@ nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
> 	DECODE_TAIL;
> }
> 
> +/*
> + * XDR data that is more than PAGE_SIZE in size is normally part of a
> + * read or write. However, the size of extended attributes is limited
> + * by the maximum request size, and then further limited by the underlying
> + * filesystem limits. This can exceed PAGE_SIZE (currently, XATTR_SIZE_MAX
> + * is 64k). Since there is no kvec- or page-based interface to xattrs,
> + * and we're not dealing with contiguous pages, we need to do some copying.
> + */
> +
> +/*
> + * Decode int to buffer.

"int" is of course a C keyword, so this typo had me confused!
I think you mean "Decode into buffer."


> Uses head and pages constructed by
> + * svcxdr_construct_vector.
> + */
> +static int
> +nfsd4_vbuf_from_stream(struct nfsd4_compoundargs *argp, struct kvec *head,
> +		       struct page **pages, char **bufp, u32 buflen)
> +{
> +	char *tmp, *dp;
> +	u32 len;
> +
> +	if (buflen <= head->iov_len) {
> +		/*
> +		 * We're in luck, the head has enough space. Just return
> +		 * the head, no need for copying.
> +		 */
> +		*bufp = head->iov_base;
> +		return 0;
> +	}
> +
> +	tmp = svcxdr_tmpalloc(argp, buflen);
> +	if (tmp == NULL)
> +		return nfserr_jukebox;
> +
> +	dp = tmp;
> +	memcpy(dp, head->iov_base, head->iov_len);
> +	buflen -= head->iov_len;
> +	dp += head->iov_len;
> +
> +	while (buflen > 0) {
> +		len = min_t(u32, buflen, PAGE_SIZE);
> +		memcpy(dp, page_address(*pages), len);
> +
> +		buflen -= len;
> +		dp += len;
> +		pages++;
> +	}
> +
> +	*bufp = tmp;
> +	return 0;
> +}
> +
> +/*
> + * Get a user extended attribute name from the XDR buffer.
> + * It will not have the "user." prefix, so prepend it.
> + * Lastly, check for nul characters in the name.
> + */
> +static int
> +nfsd4_decode_xattr_name(struct nfsd4_compoundargs *argp, char **namep)
> +{
> +	DECODE_HEAD;
> +	char *name, *sp, *dp;
> +	u32 namelen, cnt;
> +
> +	READ_BUF(4);
> +	namelen = be32_to_cpup(p++);
> +
> +	if (namelen > (XATTR_NAME_MAX - XATTR_USER_PREFIX_LEN))
> +		return nfserr_nametoolong;
> +
> +	if (namelen == 0)
> +		goto xdr_error;
> +
> +	READ_BUF(namelen);
> +
> +	name = svcxdr_tmpalloc(argp, namelen + XATTR_USER_PREFIX_LEN + 1);
> +	if (!name)
> +		return nfserr_jukebox;
> +
> +	memcpy(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
> +
> +	/*
> +	 * Copy the extended attribute name over while checking for 0
> +	 * characters.
> +	 */
> +	sp = (char *)p;
> +	dp = name + XATTR_USER_PREFIX_LEN;
> +	cnt = namelen;
> +
> +	while (cnt-- > 0) {
> +		if (*sp == '\0')
> +			goto xdr_error;
> +		*dp++ = *sp++;
> +	}
> +	*dp = '\0';
> +
> +	*namep = name;
> +
> +	DECODE_TAIL;
> +}
> +
> +/*
> + * A GETXATTR op request comes without a length specifier. We just set the
> + * maximum length for the reply based on XATTR_SIZE_MAX and the maximum
> + * channel reply size, allocate a buffer of that length and pass it to
> + * vfs_getxattr.
> + */
> +static __be32
> +nfsd4_decode_getxattr(struct nfsd4_compoundargs *argp,
> +		      struct nfsd4_getxattr *getxattr)
> +{
> +	int status;
> +	u32 maxcount;
> +
> +	status = nfsd4_decode_xattr_name(argp, &getxattr->getxa_name);
> +	if (status)
> +		return status;
> +
> +	maxcount = svc_max_payload(argp->rqstp);
> +	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
> +
> +	getxattr->getxa_buf = svcxdr_tmpalloc(argp, maxcount);
> +	if (!getxattr->getxa_buf)
> +		status = nfserr_jukebox;
> +	getxattr->getxa_len = maxcount;
> +
> +	return status;
> +}
> +
> +static __be32
> +nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
> +		      struct nfsd4_setxattr *setxattr)
> +{
> +	DECODE_HEAD;
> +	u32 flags, maxcount, size;
> +	struct kvec head;
> +	struct page **pagelist;
> +
> +	READ_BUF(4);
> +	flags = be32_to_cpup(p++);
> +
> +	if (flags > SETXATTR4_REPLACE)
> +		return nfserr_inval;
> +	setxattr->setxa_flags = flags;
> +
> +	status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
> +	if (status)
> +		return status;
> +
> +	maxcount = svc_max_payload(argp->rqstp);
> +	maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
> +
> +	READ_BUF(4);
> +	size = be32_to_cpup(p++);
> +	if (size > maxcount)
> +		return nfserr_xattr2big;
> +
> +	setxattr->setxa_len = size;
> +	if (size > 0) {
> +		status = svcxdr_construct_vector(argp, &head, &pagelist, size);
> +		if (status)
> +			return status;
> +
> +		status = nfsd4_vbuf_from_stream(argp, &head, pagelist,
> +		    &setxattr->setxa_buf, size);
> +	}

Now I'm wondering if read_bytes_from_xdr_buf() might be adequate
for this purpose, so you can avoid open-coding all of this logic.


> +
> +	DECODE_TAIL;
> +}
> +
> +static __be32
> +nfsd4_decode_listxattrs(struct nfsd4_compoundargs *argp,
> +			struct nfsd4_listxattrs *listxattrs)
> +{
> +	DECODE_HEAD;
> +	u32 maxcount;
> +
> +	READ_BUF(12);
> +	p = xdr_decode_hyper(p, &listxattrs->lsxa_cookie);
> +
> +	/*
> +	 * If the cookie  is too large to have even one user.x attribute
> +	 * plus trailing '\0' left in a maximum size buffer, it's invalid.
> +	 */
> +	if (listxattrs->lsxa_cookie >=
> +	    (XATTR_LIST_MAX / (XATTR_USER_PREFIX_LEN + 2)))
> +		return nfserr_badcookie;
> +
> +	maxcount = be32_to_cpup(p++);
> +	if (maxcount < 8)
> +		/* Always need at least 2 words (length and one character) */
> +		return nfserr_inval;
> +
> +	maxcount = min(maxcount, svc_max_payload(argp->rqstp));
> +	listxattrs->lsxa_maxcount = maxcount;
> +
> +	/*
> +	 * Unfortunately, there is no interface to only list xattrs for
> +	 * one prefix. So there is no good way to convert maxcount to
> +	 * a maximum value to pass to vfs_listxattr, as we don't know
> +	 * how many of the returned attributes will be user attributes.
> +	 *
> +	 * So, always ask vfs_listxattr for the maximum size, and encode
> +	 * as many as possible.
> +	 */
> +	listxattrs->lsxa_buf = svcxdr_tmpalloc(argp, XATTR_LIST_MAX);
> +	if (!listxattrs->lsxa_buf)
> +		status = nfserr_jukebox;
> +
> +	DECODE_TAIL;
> +}
> +
> +static __be32
> +nfsd4_decode_removexattr(struct nfsd4_compoundargs *argp,
> +			 struct nfsd4_removexattr *removexattr)
> +{
> +	return nfsd4_decode_xattr_name(argp, &removexattr->rmxa_name);
> +}
> +
> static __be32
> nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
> {
> @@ -1975,6 +2193,11 @@ static const nfsd4_dec nfsd4_dec_ops[] = {
> 	[OP_SEEK]		= (nfsd4_dec)nfsd4_decode_seek,
> 	[OP_WRITE_SAME]		= (nfsd4_dec)nfsd4_decode_notsupp,
> 	[OP_CLONE]		= (nfsd4_dec)nfsd4_decode_clone,
> +	/* RFC 8276 extended atributes operations */
> +	[OP_GETXATTR]		= (nfsd4_dec)nfsd4_decode_getxattr,
> +	[OP_SETXATTR]		= (nfsd4_dec)nfsd4_decode_setxattr,
> +	[OP_LISTXATTRS]		= (nfsd4_dec)nfsd4_decode_listxattrs,
> +	[OP_REMOVEXATTR]	= (nfsd4_dec)nfsd4_decode_removexattr,
> };
> 
> static inline bool
> @@ -4458,6 +4681,225 @@ nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *p)
> 	return nfserr;
> }
> 
> +/*
> + * Encode kmalloc-ed buffer in to XDR stream.
> + */
> +static int
> +nfsd4_vbuf_to_stream(struct xdr_stream *xdr, char *buf, u32 buflen)
> +{
> +	u32 cplen;
> +	__be32 *p;
> +
> +	cplen = min_t(unsigned long, buflen,
> +		      ((void *)xdr->end - (void *)xdr->p));
> +	p = xdr_reserve_space(xdr, cplen);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	memcpy(p, buf, cplen);
> +	buf += cplen;
> +	buflen -= cplen;
> +
> +	while (buflen) {
> +		cplen = min_t(u32, buflen, PAGE_SIZE);
> +		p = xdr_reserve_space(xdr, cplen);
> +		if (!p)
> +			return nfserr_resource;
> +
> +		memcpy(p, buf, cplen);
> +
> +		if (cplen < PAGE_SIZE) {
> +			/*
> +			 * We're done, with a length that wasn't page
> +			 * aligned, so possibly not word aligned. Pad
> +			 * any trailing bytes with 0.
> +			 */
> +			xdr_encode_opaque_fixed(p, NULL, cplen);
> +			break;
> +		}
> +
> +		buflen -= PAGE_SIZE;
> +		buf += PAGE_SIZE;
> +	}
> +
> +	return 0;
> +}
> +
> +static __be32
> +nfsd4_encode_getxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
> +		      struct nfsd4_getxattr *getxattr)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	__be32 *p;
> +
> +	p = xdr_reserve_space(xdr, 4);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	*p = cpu_to_be32(getxattr->getxa_len);
> +
> +	if (getxattr->getxa_len == 0)
> +		return 0;
> +
> +	return nfsd4_vbuf_to_stream(xdr, getxattr->getxa_buf,
> +				    getxattr->getxa_len);
> +}
> +
> +static __be32
> +nfsd4_encode_setxattr(struct nfsd4_compoundres *resp, __be32 nfserr,
> +		      struct nfsd4_setxattr *setxattr)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	__be32 *p;
> +
> +	p = xdr_reserve_space(xdr, 20);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	encode_cinfo(p, &setxattr->setxa_cinfo);
> +
> +	return 0;
> +}
> +
> +/*
> + * See if there are cookie values that can be rejected outright.
> + */
> +static int
> +nfsd4_listxattr_validate_cookie(struct nfsd4_listxattrs *listxattrs,
> +				u32 *offsetp)
> +{
> +	u64 cookie = listxattrs->lsxa_cookie;
> +
> +	/*
> +	 * If the cookie is larger than the maximum number we can fit
> +	 * in either the buffer we just got back from vfs_listxattr, or,
> +	 * XDR-encoded, in the return buffer, it's invalid.
> +	 */
> +	if (cookie > (listxattrs->lsxa_len) / (XATTR_USER_PREFIX_LEN + 2))
> +		return nfserr_badcookie;
> +
> +	if (cookie > (listxattrs->lsxa_maxcount /
> +		      (XDR_QUADLEN(XATTR_USER_PREFIX_LEN + 2) + 4)))
> +		return nfserr_badcookie;
> +
> +	*offsetp = (u32)cookie;
> +	return 0;
> +}
> +
> +static __be32
> +nfsd4_encode_listxattrs(struct nfsd4_compoundres *resp, __be32 nfserr,
> +			struct nfsd4_listxattrs *listxattrs)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	u32 cookie_offset, count_offset, eof;
> +	u32 left, xdrleft, slen, count;
> +	u32 xdrlen, offset;
> +	u64 cookie;
> +	char *sp;
> +	int status;
> +	__be32 *p;
> +	u32 nuser;
> +
> +	eof = 1;
> +
> +	status = nfsd4_listxattr_validate_cookie(listxattrs, &offset);
> +	if (status)
> +		return status;
> +
> +	/*
> +	 * Reserve space for the cookie and the name array count. Record
> +	 * the offsets to save them later.
> +	 */
> +	cookie_offset = xdr->buf->len;
> +	count_offset = cookie_offset + 8;
> +	p = xdr_reserve_space(xdr, 12);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	count = 0;
> +	left = listxattrs->lsxa_len;
> +	sp = listxattrs->lsxa_buf;
> +	nuser = 0;
> +
> +	xdrleft = listxattrs->lsxa_maxcount;
> +
> +	while (left > 0 && xdrleft > 0) {
> +		slen = strlen(sp);
> +
> +		/*
> +		 * Check if this a user. attribute, skip it if not.
> +		 */
> +		if (strncmp(sp, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
> +			goto contloop;
> +
> +		slen -= XATTR_USER_PREFIX_LEN;
> +		xdrlen = 4 + ((slen + 3) & ~3);
> +		if (xdrlen > xdrleft) {
> +			if (count == 0) {
> +				/*
> +				 * Can't even fit the first attribute name.
> +				 */
> +				return nfserr_toosmall;
> +			}
> +			eof = 0;
> +			goto wreof;
> +		}
> +
> +		left -= XATTR_USER_PREFIX_LEN;
> +		sp += XATTR_USER_PREFIX_LEN;
> +		if (nuser++ < offset)
> +			goto contloop;
> +
> +
> +		p = xdr_reserve_space(xdr, xdrlen);
> +		if (!p)
> +			return nfserr_resource;
> +
> +		p = xdr_encode_opaque(p, sp, slen);
> +
> +		xdrleft -= xdrlen;
> +		count++;
> +contloop:
> +		sp += slen + 1;
> +		left -= slen + 1;
> +	}
> +
> +	/*
> +	 * If there were user attributes to copy, but we didn't copy
> +	 * any, the offset was too large (e.g. the cookie was invalid).
> +	 */
> +	if (nuser > 0 && count == 0)
> +		return nfserr_badcookie;
> +
> +wreof:
> +	p = xdr_reserve_space(xdr, 4);
> +	if (!p)
> +		return nfserr_resource;
> +	*p = cpu_to_be32(eof);
> +
> +	cookie = offset + count;
> +
> +	write_bytes_to_xdr_buf(xdr->buf, cookie_offset, &cookie, 8);
> +	count = htonl(count);
> +	write_bytes_to_xdr_buf(xdr->buf, count_offset, &count, 4);
> +	return 0;
> +}
> +
> +static __be32
> +nfsd4_encode_removexattr(struct nfsd4_compoundres *resp, __be32 nfserr,
> +			 struct nfsd4_removexattr *removexattr)
> +{
> +	struct xdr_stream *xdr = &resp->xdr;
> +	__be32 *p;
> +
> +	p = xdr_reserve_space(xdr, 20);
> +	if (!p)
> +		return nfserr_resource;
> +
> +	p = encode_cinfo(p, &removexattr->rmxa_cinfo);
> +	return 0;
> +}
> +
> typedef __be32(* nfsd4_enc)(struct nfsd4_compoundres *, __be32, void *);
> 
> /*
> @@ -4547,6 +4989,12 @@ static const nfsd4_enc nfsd4_enc_ops[] = {
> 	[OP_SEEK]		= (nfsd4_enc)nfsd4_encode_seek,
> 	[OP_WRITE_SAME]		= (nfsd4_enc)nfsd4_encode_noop,
> 	[OP_CLONE]		= (nfsd4_enc)nfsd4_encode_noop,
> +
> +	/* RFC 8276 extended atributes operations */
> +	[OP_GETXATTR]		= (nfsd4_enc)nfsd4_encode_getxattr,
> +	[OP_SETXATTR]		= (nfsd4_enc)nfsd4_encode_setxattr,
> +	[OP_LISTXATTRS]		= (nfsd4_enc)nfsd4_encode_listxattrs,
> +	[OP_REMOVEXATTR]	= (nfsd4_enc)nfsd4_encode_removexattr,
> };
> 
> /*
> -- 
> 2.16.6
> 

--
Chuck Lever

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Frank van der Linden]

Hi Chuck,

On Thu, Mar 12, 2020 at 03:16:37PM -0400, Chuck Lever wrote:
> > +static __be32
> > +nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
> > +                   struct nfsd4_setxattr *setxattr)
> > +{
> > +     DECODE_HEAD;
> > +     u32 flags, maxcount, size;
> > +     struct kvec head;
> > +     struct page **pagelist;
> > +
> > +     READ_BUF(4);
> > +     flags = be32_to_cpup(p++);
> > +
> > +     if (flags > SETXATTR4_REPLACE)
> > +             return nfserr_inval;
> > +     setxattr->setxa_flags = flags;
> > +
> > +     status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
> > +     if (status)
> > +             return status;
> > +
> > +     maxcount = svc_max_payload(argp->rqstp);
> > +     maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
> > +
> > +     READ_BUF(4);
> > +     size = be32_to_cpup(p++);
> > +     if (size > maxcount)
> > +             return nfserr_xattr2big;
> > +
> > +     setxattr->setxa_len = size;
> > +     if (size > 0) {
> > +             status = svcxdr_construct_vector(argp, &head, &pagelist, size);
> > +             if (status)
> > +                     return status;
> > +
> > +             status = nfsd4_vbuf_from_stream(argp, &head, pagelist,
> > +                 &setxattr->setxa_buf, size);
> > +     }
> 
> Now I'm wondering if read_bytes_from_xdr_buf() might be adequate
> for this purpose, so you can avoid open-coding all of this logic.

This took a little longer, I had to check my notes, but basically the
reasons for doing it this way are:

* The nfsd decode path uses nfsd4_compoundargs, which doesn't have an
  xdr_stream (it has a page array). So read_bytes_from_xdr_buf isn't
  a natural fit.
* READ_BUF/read_buf don't deal with > PAGE_SIZE chunks, but xattrs may
  be larger than that.

The other code that deals with > PAGE_SIZE chunks is the write code. So,
I factored out some code from the write code, used that, and added a function
to process the resulting kvec / pagelist (nfs4_vbuf_from_stream).

There definitely seem to be several copy functions in both the client
and server code that basically do the same, but in slightly different ways,
depending on whether they use an XDR buf or not, whether the pages are
mapped or not, etc. Seems like a good candidate for a cleanup, but I
considered it to be out of scope for these patches.

- Frank

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Chuck Lever]

> On Mar 20, 2020, at 12:47 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> Hi Chuck,
> 
> On Thu, Mar 12, 2020 at 03:16:37PM -0400, Chuck Lever wrote:
>>> +static __be32
>>> +nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
>>> +                   struct nfsd4_setxattr *setxattr)
>>> +{
>>> +     DECODE_HEAD;
>>> +     u32 flags, maxcount, size;
>>> +     struct kvec head;
>>> +     struct page **pagelist;
>>> +
>>> +     READ_BUF(4);
>>> +     flags = be32_to_cpup(p++);
>>> +
>>> +     if (flags > SETXATTR4_REPLACE)
>>> +             return nfserr_inval;
>>> +     setxattr->setxa_flags = flags;
>>> +
>>> +     status = nfsd4_decode_xattr_name(argp, &setxattr->setxa_name);
>>> +     if (status)
>>> +             return status;
>>> +
>>> +     maxcount = svc_max_payload(argp->rqstp);
>>> +     maxcount = min_t(u32, XATTR_SIZE_MAX, maxcount);
>>> +
>>> +     READ_BUF(4);
>>> +     size = be32_to_cpup(p++);
>>> +     if (size > maxcount)
>>> +             return nfserr_xattr2big;
>>> +
>>> +     setxattr->setxa_len = size;
>>> +     if (size > 0) {
>>> +             status = svcxdr_construct_vector(argp, &head, &pagelist, size);
>>> +             if (status)
>>> +                     return status;
>>> +
>>> +             status = nfsd4_vbuf_from_stream(argp, &head, pagelist,
>>> +                 &setxattr->setxa_buf, size);
>>> +     }
>> 
>> Now I'm wondering if read_bytes_from_xdr_buf() might be adequate
>> for this purpose, so you can avoid open-coding all of this logic.
> 
> This took a little longer, I had to check my notes,

Thanks for checking!

> but basically the reasons for doing it this way are:
> 
> * The nfsd decode path uses nfsd4_compoundargs, which doesn't have an
>  xdr_stream (it has a page array). So read_bytes_from_xdr_buf isn't
>  a natural fit.
> * READ_BUF/read_buf don't deal with > PAGE_SIZE chunks, but xattrs may
>  be larger than that.
> 
> The other code that deals with > PAGE_SIZE chunks is the write code. So,
> I factored out some code from the write code, used that, and added a function
> to process the resulting kvec / pagelist (nfs4_vbuf_from_stream).

Yes, I only recently discovered that the xdr_stream helpers do not
work for decoding data items that are page size or larger.

For the record, my IMA prototype takes this approach for decode_fattr:

+       if (bmval[2] & FATTR4_WORD2_IMA) {
+               READ_BUF(4);
+               len += 4;
+               dummy32 = be32_to_cpup(p++);
+               READ_BUF(dummy32);
+               if (dummy32 > NFS4_MAXIMALEN)
+                       return nfserr_badlabel;
+               *ima = svcxdr_tmpalloc(argp, sizeof(**ima));
+               if (*ima == NULL)
+                       return nfserr_jukebox;
+
+               len += (XDR_QUADLEN(dummy32) << 2);
+               READMEM(buf, dummy32);
+               (*ima)->len = dummy32;
+               (*ima)->data = svcxdr_dupstr(argp, buf, dummy32);
+               if ((*ima)->data == NULL)
+                       return nfserr_jukebox;
+       } else
+               ima = NULL;

Although, an IMA blob is never larger than a page, IIRC.

> There definitely seem to be several copy functions in both the client
> and server code that basically do the same, but in slightly different ways,
> depending on whether they use an XDR buf or not, whether the pages are
> mapped or not, etc. Seems like a good candidate for a cleanup, but I
> considered it to be out of scope for these patches.

"out of scope" - probably so. Depending on Bruce's thinking, we can
add this to the list of janitorial tasks.

For my peace of mind, "from_stream" implies there _is_ an xdr_stream
in use, even though the function does not have a struct xdr_stream
parameter. Perhaps a different naming scheme would be wise.


--
Chuck Lever

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[J. Bruce Fields]

On Fri, Mar 20, 2020 at 01:34:53PM -0400, Chuck Lever wrote:
> 
> 
> > On Mar 20, 2020, at 12:47 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> > There definitely seem to be several copy functions in both the client
> > and server code that basically do the same, but in slightly different ways,
> > depending on whether they use an XDR buf or not, whether the pages are
> > mapped or not, etc. Seems like a good candidate for a cleanup, but I
> > considered it to be out of scope for these patches.
> 
> "out of scope" - probably so. Depending on Bruce's thinking, we can
> add this to the list of janitorial tasks.

The rewrite of the server xdr encoding was... oh jeez, six years ago
now, and I haven't really thought about it since.  I remember thinking
we should do the decode side as well someday, though, and thinking it
should be pretty doable.

--b.

Re: [PATCH 11/14] nfsd: add user xattr RPC XDR encoding/decoding logic

[Frank van der Linden]

On Fri, Mar 20, 2020 at 01:34:53PM -0400, Chuck Lever wrote:
> 
> For my peace of mind, "from_stream" implies there _is_ an xdr_stream
> in use, even though the function does not have a struct xdr_stream
> parameter. Perhaps a different naming scheme would be wise.

Sure. I'll change it to "from_vector", which matches the name of the
"svcxdr_construct_vector" function. Not 100% correct, since it's really
a vector + page array, but it seems better.

- Frank

[PATCH 12/14] nfsd: add xattr operations to ops array

[Frank van der Linden]

With all underlying code implemented, let's add the user extended
attributes operations to nfsd4_ops.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4proc.c   | 22 ++++++++++++++++++++++
 include/linux/nfs4.h |  2 +-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 44d488bdebd9..889cb6538244 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -3195,6 +3195,28 @@ static const struct nfsd4_operation nfsd4_ops[LAST_NFS4_OP + 1] = {
 		.op_name = "OP_COPY_NOTIFY",
 		.op_rsize_bop = nfsd4_copy_notify_rsize,
 	},
+	[OP_GETXATTR] = {
+		.op_func = nfsd4_getxattr,
+		.op_name = "OP_GETXATTR",
+		.op_rsize_bop = nfsd4_getxattr_rsize,
+	},
+	[OP_SETXATTR] = {
+		.op_func = nfsd4_setxattr,
+		.op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
+		.op_name = "OP_SETXATTR",
+		.op_rsize_bop = nfsd4_setxattr_rsize,
+	},
+	[OP_LISTXATTRS] = {
+		.op_func = nfsd4_listxattrs,
+		.op_name = "OP_LISTXATTRS",
+		.op_rsize_bop = nfsd4_listxattrs_rsize,
+	},
+	[OP_REMOVEXATTR] = {
+		.op_func = nfsd4_removexattr,
+		.op_flags = OP_MODIFIES_SOMETHING | OP_CACHEME,
+		.op_name = "OP_REMOVEXATTR",
+		.op_rsize_bop = nfsd4_removexattr_rsize,
+	},
 };
 
 /**
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 350aeda0c48c..cbe50e452f19 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -165,7 +165,7 @@ Needs to be updated if more operations are defined in future.*/
 #define FIRST_NFS4_OP	OP_ACCESS
 #define LAST_NFS40_OP	OP_RELEASE_LOCKOWNER
 #define LAST_NFS41_OP	OP_RECLAIM_COMPLETE
-#define LAST_NFS42_OP	OP_CLONE
+#define LAST_NFS42_OP	OP_REMOVEXATTR
 #define LAST_NFS4_OP	LAST_NFS42_OP
 
 enum nfsstat4 {
-- 
2.16.6

[PATCH 13/14] xattr: add a function to check if a namespace is supported

[Frank van der Linden]

Add a function that checks is an extended attribute namespace is
supported for an inode.

To be used by the nfs server code when being queried for extended
attributes support.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/xattr.c            | 27 +++++++++++++++++++++++++++
 include/linux/xattr.h |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/fs/xattr.c b/fs/xattr.c
index 58013bcbc333..7d0ebab1df30 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -134,6 +134,33 @@ xattr_permission(struct inode *inode, const char *name, int mask)
 	return inode_permission(inode, mask);
 }
 
+/*
+ * Look for any handler that deals with the specified namespace.
+ */
+int
+xattr_supported_namespace(struct inode *inode, const char *prefix)
+{
+	const struct xattr_handler **handlers = inode->i_sb->s_xattr;
+	const struct xattr_handler *handler;
+	size_t preflen;
+
+	if (!(inode->i_opflags & IOP_XATTR)) {
+		if (unlikely(is_bad_inode(inode)))
+			return -EIO;
+		return -EOPNOTSUPP;
+	}
+
+	preflen = strlen(prefix);
+
+	for_each_xattr_handler(handlers, handler) {
+		if (!strncmp(xattr_prefix(handler), prefix, preflen))
+			return 0;
+	}
+
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL(xattr_supported_namespace);
+
 int
 __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
 	       const void *value, size_t size, int flags)
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index 3a71ad716da5..32e377602068 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -61,6 +61,8 @@ ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_siz
 ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
 			   char **xattr_value, size_t size, gfp_t flags);
 
+int xattr_supported_namespace(struct inode *inode, const char *prefix);
+
 static inline const char *xattr_prefix(const struct xattr_handler *handler)
 {
 	return handler->prefix ?: handler->name;
-- 
2.16.6

Re: [PATCH 13/14] xattr: add a function to check if a namespace is supported

[Chuck Lever]

> On Mar 11, 2020, at 3:59 PM, Frank van der Linden <fllinden@amazon.com> wrote:
> 
> Add a function that checks is an extended attribute namespace is
> supported for an inode.
> 
> To be used by the nfs server code when being queried for extended
> attributes support.

Here's a patch that needs to be cc: linux-fsdevel.

Also, perhaps 13/14 and 14/14 could be squashed together.


> Signed-off-by: Frank van der Linden <fllinden@amazon.com>
> ---
> fs/xattr.c            | 27 +++++++++++++++++++++++++++
> include/linux/xattr.h |  2 ++
> 2 files changed, 29 insertions(+)
> 
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 58013bcbc333..7d0ebab1df30 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -134,6 +134,33 @@ xattr_permission(struct inode *inode, const char *name, int mask)
> 	return inode_permission(inode, mask);
> }
> 
> +/*
> + * Look for any handler that deals with the specified namespace.
> + */
> +int
> +xattr_supported_namespace(struct inode *inode, const char *prefix)
> +{
> +	const struct xattr_handler **handlers = inode->i_sb->s_xattr;
> +	const struct xattr_handler *handler;
> +	size_t preflen;
> +
> +	if (!(inode->i_opflags & IOP_XATTR)) {
> +		if (unlikely(is_bad_inode(inode)))
> +			return -EIO;
> +		return -EOPNOTSUPP;
> +	}
> +
> +	preflen = strlen(prefix);
> +
> +	for_each_xattr_handler(handlers, handler) {
> +		if (!strncmp(xattr_prefix(handler), prefix, preflen))
> +			return 0;
> +	}
> +
> +	return -EOPNOTSUPP;
> +}
> +EXPORT_SYMBOL(xattr_supported_namespace);
> +
> int
> __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
> 	       const void *value, size_t size, int flags)
> diff --git a/include/linux/xattr.h b/include/linux/xattr.h
> index 3a71ad716da5..32e377602068 100644
> --- a/include/linux/xattr.h
> +++ b/include/linux/xattr.h
> @@ -61,6 +61,8 @@ ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_siz
> ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
> 			   char **xattr_value, size_t size, gfp_t flags);
> 
> +int xattr_supported_namespace(struct inode *inode, const char *prefix);
> +
> static inline const char *xattr_prefix(const struct xattr_handler *handler)
> {
> 	return handler->prefix ?: handler->name;
> -- 
> 2.16.6
> 

--
Chuck Lever

[PATCH 14/14] nfsd: add fattr support for user extended attributes

[Frank van der Linden]

Check if user extended attributes are supported for an inode,
and return the answer when being queried for file attributes.

An exported filesystem can now signal its RFC8276 user extended
attributes capability.

Signed-off-by: Frank van der Linden <fllinden@amazon.com>
---
 fs/nfsd/nfs4xdr.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 41c8b95ca1c5..d4a45cfefb86 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3229,6 +3229,15 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	}
 #endif
 
+	if (bmval2 & FATTR4_WORD2_XATTR_SUPPORT) {
+		p = xdr_reserve_space(xdr, 4);
+		if (!p)
+			goto out_resource;
+		err = xattr_supported_namespace(d_inode(dentry),
+						XATTR_USER_PREFIX);
+		*p++ = cpu_to_be32(err == 0);
+	}
+
 	attrlen = htonl(xdr->buf->len - attrlen_offset - 4);
 	write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, 4);
 	status = nfs_ok;
-- 
2.16.6