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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Ronnie Sahlberg <lsahlber@redhat.com>,
        Steve French <stfrench@microsoft.com>,
        Sasha Levin <sashal@kernel.org>, linux-cifs@vger.kernel.org,
        samba-technical@lists.samba.org
Subject: [PATCH AUTOSEL 5.4 70/80] cifs: handle -EINTR in cifs_setattr
Date:   Mon, 26 Oct 2020 19:55:06 -0400
Message-Id: <20201026235516.1025100-70-sashal@kernel.org>
In-Reply-To: <20201026235516.1025100-1-sashal@kernel.org>
References: <20201026235516.1025100-1-sashal@kernel.org>
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From: Ronnie Sahlberg <lsahlber@redhat.com>

[ Upstream commit c6cc4c5a72505a0ecefc9b413f16bec512f38078 ]

RHBZ: 1848178

Some calls that set attributes, like utimensat(), are not supposed to return
-EINTR and thus do not have handlers for this in glibc which causes us
to leak -EINTR to the applications which are also unprepared to handle it.

For example tar will break if utimensat() return -EINTR and abort unpacking
the archive. Other applications may break too.

To handle this we add checks, and retry, for -EINTR in cifs_setattr()

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/inode.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 17df90b5f57a2..fd9e289f3e72a 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2614,13 +2614,18 @@ cifs_setattr(struct dentry *direntry, struct iattr *attrs)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 	struct cifs_tcon *pTcon = cifs_sb_master_tcon(cifs_sb);
+	int rc, retries = 0;
 
-	if (pTcon->unix_ext)
-		return cifs_setattr_unix(direntry, attrs);
-
-	return cifs_setattr_nounix(direntry, attrs);
+	do {
+		if (pTcon->unix_ext)
+			rc = cifs_setattr_unix(direntry, attrs);
+		else
+			rc = cifs_setattr_nounix(direntry, attrs);
+		retries++;
+	} while (is_retryable_error(rc) && retries < 2);
 
 	/* BB: add cifs_setattr_legacy for really old servers */
+	return rc;
 }
 
 #if 0
-- 
2.25.1