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From: Frank van der Linden <fllinden@amazon.com>
To: <linux-nfs@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>
Subject: [RFC PATCH 24/35] nfsd: define xattr functions to call in to their vfs counterparts
Date: Sat, 31 Aug 2019 23:53:14 +0000
Message-ID: <fb951c1cfcef37751ee8ff59563de2896e332ef1.1568309119.git.fllinden@amazon.com> (raw)
In-Reply-To: <cover.1568309119.git.fllinden@amazon.com>

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 | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/nfsd/vfs.h |  10 ++++
 2 files changed, 139 insertions(+)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index c85783e536d5..99363e7ce044 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1990,6 +1990,135 @@ static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp)
 	return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY;
 }
 
+#ifdef CONFIG_NFSD_V4_XATTR
+/*
+ * 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 db351247892d..ef4e6eaf9c78 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -75,6 +75,16 @@ __be32		do_nfsd_create(struct svc_rqst *, struct svc_fh *,
 __be32		nfsd_commit(struct svc_rqst *, struct svc_fh *,
 				loff_t, unsigned long);
 #endif /* CONFIG_NFSD_V3 */
+#ifdef CONFIG_NFSD_V4_XATTR
+__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
 __be32		nfsd_open(struct svc_rqst *, struct svc_fh *, umode_t,
 				int, struct file **);
 struct raparms;
-- 
2.17.2


  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-12 17:25 [RFC PATCH 00/35] user xattr support (RFC8276) Frank van der Linden
2019-07-01 17:56 ` [RFC PATCH 02/35] nfs/nfsd: basic NFS4 extended attribute definitions Frank van der Linden
2019-08-26 21:38 ` [RFC PATCH 03/35] NFSv4.2: query the server for extended attribute support Frank van der Linden
2019-08-26 21:53 ` [RFC PATCH 04/35] nfs: parse the {no}user_xattr option Frank van der Linden
2019-08-26 22:06 ` [RFC PATCH 05/35] NFSv4.2: define a function to compute the maximum XDR size for listxattr Frank van der Linden
2019-08-26 22:23 ` [RFC PATCH 06/35] NFSv4.2: define and set initial limits for extended attributes Frank van der Linden
2019-08-26 22:32 ` [RFC PATCH 07/35] NFSv4.2: define argument and response structures for xattr operations Frank van der Linden
2019-08-26 22:44 ` [RFC PATCH 08/35] NFSv4.2: define the encode/decode sizes for the XATTR operations Frank van der Linden
2019-08-26 23:09 ` [RFC PATCH 09/35] NFSv4.2: define and use extended attribute overhead sizes Frank van der Linden
2019-08-27 15:34 ` [RFC PATCH 10/35] NFSv4.2: add client side XDR handling for extended attributes Frank van der Linden
2019-08-27 15:46 ` [RFC PATCH 11/35] nfs: define nfs_access_get_cached function Frank van der Linden
2019-08-27 16:01 ` [RFC PATCH 12/35] NFSv4.2: query the extended attribute access bits Frank van der Linden
2019-08-27 22:51 ` [RFC PATCH 13/35] nfs: modify update_changeattr to deal with regular files Frank van der Linden
2019-08-30 22:48 ` [RFC PATCH 14/35] nfs: define and use the NFS_INO_INVALID_XATTR flag Frank van der Linden
2019-08-30 22:56 ` [RFC PATCH 15/35] nfs: make the buf_to_pages_noslab function available to the nfs code Frank van der Linden
2019-08-30 23:15 ` [RFC PATCH 16/35] NFSv4.2: add the extended attribute proc functions Frank van der Linden
2019-08-30 23:31 ` [RFC PATCH 17/35] NFSv4.2: hook in the user extended attribute handlers Frank van der Linden
2019-08-30 23:38 ` [RFC PATCH 18/35] NFSv4.2: add client side xattr caching functions Frank van der Linden
2019-08-30 23:45 ` [RFC PATCH 19/35] NFSv4.2: call the xattr cache functions Frank van der Linden
2019-08-30 23:59 ` [RFC PATCH 20/35] nfs: add the NFS_V4_XATTR config option Frank van der Linden
2019-08-31  2:12 ` [RFC PATCH 21/35] xattr: modify vfs_{set,remove}xattr for NFS server use Frank van der Linden
2019-08-31 19:00 ` [RFC PATCH 22/35] nfsd: split off the write decode code in to a seperate function Frank van der Linden
2019-08-31 19:19 ` [RFC PATCH 23/35] nfsd: add defines for NFSv4.2 extended attribute support Frank van der Linden
2019-08-31 21:35 ` [RFC PATCH 26/35] nfsd: add structure definitions for xattr requests / responses Frank van der Linden
2019-08-31 23:53 ` Frank van der Linden [this message]
2019-09-01  0:13 ` [RFC PATCH 25/35] nfsd: take xattr access bits in to account when checking Frank van der Linden
2019-09-01  1:19 ` [RFC PATCH 27/35] nfsd: implement the xattr procedure functions Frank van der Linden
2019-09-01  2:46 ` [RFC PATCH 01/35] nfsd: make sure the nfsd4_ops array has the right size Frank van der Linden
2019-09-02 19:40 ` [RFC PATCH 28/35] nfsd: define xattr reply size functions Frank van der Linden
2019-09-02 19:58 ` [RFC PATCH 29/35] nfsd: add xattr XDR decode functions Frank van der Linden
2019-09-02 20:09 ` [RFC PATCH 30/35] nfsd: add xattr XDR encode functions Frank van der Linden
2019-09-02 20:19 ` [RFC PATCH 31/35] nfsd: add xattr operations to ops array Frank van der Linden
2019-09-02 20:34 ` [RFC PATCH 32/35] xattr: add a function to check if a namespace is supported Frank van der Linden
2019-09-02 21:30 ` [RFC PATCH 33/35] nfsd: add fattr support for user extended attributes Frank van der Linden
2019-09-02 23:06 ` [RFC PATCH 34/35] nfsd: add export flag to disable " Frank van der Linden
2019-09-02 23:17 ` [RFC PATCH 35/35] nfsd: add NFSD_V4_XATTR config option Frank van der Linden
2019-10-24 20:16 ` [RFC PATCH 00/35] user xattr support (RFC8276) Chuck Lever
2019-10-24 23:15   ` Frank van der Linden
2019-10-25 19:55     ` Chuck Lever
2019-11-04  3:01       ` bfields
2019-11-04 15:36         ` Chuck Lever
2019-11-04 16:21           ` Frank van der Linden
2019-11-04 22:58             ` Bruce Fields
2019-11-05  0:06               ` Frank van der Linden
2019-11-05 15:44               ` Chuck Lever

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