From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Wed, 25 Aug 2021 21:16:56 +1000
Subject: [PATCH] cifs: Do not leak EDEADLK to dgetents64 for
STATUS_USER_SESSION_DELETED
Git-commit: 3998f0b8bc49ec784990971dc1f16bf367b19078
References: bsc#1190317
Patch-mainline: v5.14
RHBZ: 1994393
If we hit a STATUS_USER_SESSION_DELETED for the Create part in the
Create/QueryDirectory compound that starts a directory scan
we will leak EDEADLK back to userspace and surprise glibc and the application.
Pick this up initiate_cifs_search() and retry a small number of tries before we
return an error to userspace.
Cc: stable@vger.kernel.org
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
fs/cifs/readdir.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index bfee176b901d..54d77c99e21c 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -369,7 +369,7 @@ int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
*/
static int
-initiate_cifs_search(const unsigned int xid, struct file *file,
+_initiate_cifs_search(const unsigned int xid, struct file *file,
const char *full_path)
{
__u16 search_flags;
@@ -451,6 +451,27 @@ initiate_cifs_search(const unsigned int xid, struct file *file,
return rc;
}
+static int
+initiate_cifs_search(const unsigned int xid, struct file *file,
+ const char *full_path)
+{
+ int rc, retry_count = 0;
+
+ do {
+ rc = _initiate_cifs_search(xid, file, full_path);
+ /*
+ * If we don't have enough credits to start reading the
+ * directory just try again after short wait.
+ */
+ if (rc != -EDEADLK)
+ break;
+
+ usleep_range(512, 2048);
+ } while (retry_count++ < 5);
+
+ return rc;
+}
+
/* return length of unicode string in bytes */
static int cifs_unicode_bytelen(const char *str)
{
--
2.33.1