linux-kernel - [PATCH 3.2 073/185] nfsd: make sure to balance get/put_write

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Message-ID: <lsq.1388282923.601886880@decadent.org.uk>
Date:	Sun, 29 Dec 2013 03:08:43 +0100
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org, "J. Bruce Fields" <bfields@...hat.com>,
	"Christoph Hellwig" <hch@...radead.org>,
	"Christoph Hellwig" <hch@....de>
Subject: [PATCH 3.2 073/185] nfsd: make sure to balance get/put_write_access

3.2.54-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Christoph Hellwig <hch@...radead.org>

commit 987da4791052fa298b7cfcde4dea9f6f2bbc786b upstream.

Use a straight goto error label style in nfsd_setattr to make sure
we always do the put_write_access call after we got it earlier.

Note that the we have been failing to do that in the case
nfsd_break_lease() returns an error, a bug introduced into 2.6.38 with
6a76bebefe15d9a08864f824d7f8d5beaf37c997 "nfsd4: break lease on nfsd
setattr".

Signed-off-by: Christoph Hellwig <hch@....de>
Signed-off-by: J. Bruce Fields <bfields@...hat.com>
[bwh: Backported to 3.2: notify_change() takes only 2 arguments]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/nfsd/vfs.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -443,27 +443,28 @@ nfsd_setattr(struct svc_rqst *rqstp, str
 
 	iap->ia_valid |= ATTR_CTIME;
 
-	err = nfserr_notsync;
-	if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
-		host_err = nfsd_break_lease(inode);
-		if (host_err)
-			goto out_nfserr;
-		fh_lock(fhp);
-
-		host_err = notify_change(dentry, iap);
-		err = nfserrno(host_err);
-		fh_unlock(fhp);
+	if (check_guard && guardtime != inode->i_ctime.tv_sec) {
+		err = nfserr_notsync;
+		goto out_put_write_access;
 	}
+
+	host_err = nfsd_break_lease(inode);
+	if (host_err)
+		goto out_put_write_access_nfserror;
+
+	fh_lock(fhp);
+	host_err = notify_change(dentry, iap);
+	fh_unlock(fhp);
+
+out_put_write_access_nfserror:
+	err = nfserrno(host_err);
+out_put_write_access:
 	if (size_change)
 		put_write_access(inode);
 	if (!err)
 		commit_metadata(fhp);
 out:
 	return err;
-
-out_nfserr:
-	err = nfserrno(host_err);
-	goto out;
 }
 
 #if defined(CONFIG_NFSD_V2_ACL) || \

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