From patchwork Tue Jun 23 22:39:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank van der Linden X-Patchwork-Id: 11621969 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AEF1513B1 for ; Tue, 23 Jun 2020 22:44:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 971BF20888 for ; Tue, 23 Jun 2020 22:44:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="IbObUtrj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387763AbgFWWoT (ORCPT ); Tue, 23 Jun 2020 18:44:19 -0400 Received: from smtp-fw-33001.amazon.com ([207.171.190.10]:14761 "EHLO smtp-fw-33001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387916AbgFWWoN (ORCPT ); Tue, 23 Jun 2020 18:44:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1592952251; x=1624488251; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=ORvRYyTPp6jlWv0S7OnPPAwzsBtrMSNsJYv8Oe8JM3I=; b=IbObUtrjNDE7hy+nHHnQN/+ckzCCrpi8989Oh/IZsNfvTRCAQ1PnRhyf m6P240urcnCfxMCBTCLp0aIHzeeNee7qGs80//yFPZ5DMq2wviL0lbFrc CgN7uf6gwAdKviLkMAlsEQ9K4EGFegA3yPVUIB5OeUMcmp9MeJPn9qML9 c=; IronPort-SDR: 5uxnEEpo/XzZ25ZQzP+js6OBLtX5qiOmY+un/cV3K4Q+ejXXwdaLjgbwtlp9HFlKv8i4DGEnMU qwT4pMFn/KaQ== X-IronPort-AV: E=Sophos;i="5.75,272,1589241600"; d="scan'208";a="53337284" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-2c-4e7c8266.us-west-2.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 23 Jun 2020 22:39:39 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2c-4e7c8266.us-west-2.amazon.com (Postfix) with ESMTPS id A5B78A0103; Tue, 23 Jun 2020 22:39:37 +0000 (UTC) Received: from EX13D13UWB001.ant.amazon.com (10.43.161.156) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 23 Jun 2020 22:39:29 +0000 Received: from EX13MTAUEB002.ant.amazon.com (10.43.60.12) by EX13D13UWB001.ant.amazon.com (10.43.161.156) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 23 Jun 2020 22:39:29 +0000 Received: from dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com (172.23.141.97) by mail-relay.amazon.com (10.43.60.234) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 23 Jun 2020 22:39:28 +0000 Received: by dev-dsk-fllinden-2c-c1893d73.us-west-2.amazon.com (Postfix, from userid 6262777) id 18365CD360; Tue, 23 Jun 2020 22:39:28 +0000 (UTC) From: Frank van der Linden To: , , CC: Frank van der Linden Subject: [PATCH v3 06/10] nfsd: define xattr functions to call in to their vfs counterparts Date: Tue, 23 Jun 2020 22:39:23 +0000 Message-ID: <20200623223927.31795-7-fllinden@amazon.com> X-Mailer: git-send-email 2.16.6 In-Reply-To: <20200623223927.31795-1-fllinden@amazon.com> References: <20200623223927.31795-1-fllinden@amazon.com> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org 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 --- fs/nfsd/vfs.c | 227 ++++++++++++++++++++++++++++++++++++++++++++++++++ fs/nfsd/vfs.h | 10 +++ 2 files changed, 237 insertions(+) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index c3fbab1753ec..b1dd8690e25d 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -2059,6 +2059,233 @@ 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); +} + +/* + * Retrieve the specified user extended attribute. To avoid always + * having to allocate the maximum size (since we are not getting + * a maximum size from the RPC), do a probe + alloc. Hold a reader + * lock on i_rwsem to prevent the extended attribute from changing + * size while we're doing this. + */ +__be32 +nfsd_getxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name, + void **bufp, int *lenp) +{ + ssize_t len; + __be32 err; + char *buf; + struct inode *inode; + struct dentry *dentry; + + err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); + if (err) + return err; + + err = nfs_ok; + dentry = fhp->fh_dentry; + inode = d_inode(dentry); + + inode_lock_shared(inode); + + len = vfs_getxattr(dentry, name, NULL, 0); + + /* + * Zero-length attribute, just return. + */ + if (len == 0) { + *bufp = NULL; + *lenp = 0; + goto out; + } + + if (len < 0) { + err = nfsd_xattr_errno(len); + goto out; + } + + if (len > *lenp) { + err = nfserr_toosmall; + goto out; + } + + buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); + if (buf == NULL) { + err = nfserr_jukebox; + goto out; + } + + len = vfs_getxattr(dentry, name, buf, len); + if (len <= 0) { + kvfree(buf); + buf = NULL; + err = nfsd_xattr_errno(len); + } + + *lenp = len; + *bufp = buf; + +out: + inode_unlock_shared(inode); + + return err; +} + +/* + * Retrieve the xattr names. Since we can't know how many are + * user extended attributes, we must get all attributes here, + * and have the XDR encode filter out the "user." ones. + * + * While this could always just allocate an XATTR_LIST_MAX + * buffer, that's a waste, so do a probe + allocate. To + * avoid any changes between the probe and allocate, wrap + * this in inode_lock. + */ +__be32 +nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char **bufp, + int *lenp) +{ + ssize_t len; + __be32 err; + char *buf; + struct inode *inode; + struct dentry *dentry; + + err = fh_verify(rqstp, fhp, 0, NFSD_MAY_READ); + if (err) + return err; + + dentry = fhp->fh_dentry; + inode = d_inode(dentry); + *lenp = 0; + + inode_lock_shared(inode); + + len = vfs_listxattr(dentry, NULL, 0); + if (len <= 0) { + err = nfsd_xattr_errno(len); + goto out; + } + + if (len > XATTR_LIST_MAX) { + err = nfserr_xattr2big; + goto out; + } + + /* + * We're holding i_rwsem - use GFP_NOFS. + */ + buf = kvmalloc(len, GFP_KERNEL | GFP_NOFS); + if (buf == NULL) { + err= nfserr_jukebox; + goto out; + } + + len = vfs_listxattr(dentry, buf, len); + if (len <= 0) { + kvfree(buf); + err = nfsd_xattr_errno(len); + goto out; + } + + *lenp = len; + *bufp = buf; + + err = nfs_ok; +out: + inode_unlock_shared(inode); + + 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..a2442ebe5acf 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 **bufp, int *lenp); +__be32 nfsd_listxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, + char **bufp, 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 **);