[PATCH 5.13 274/300] cifs: Do not leak EDEADLK to dgetents64 for STATUS_USER_SESSION_DELETED
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-09-13 14:20:16
Also in:
lkml
From: Ronnie Sahlberg <redacted> commit 3998f0b8bc49ec784990971dc1f16bf367b19078 upstream. 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 <redacted> Signed-off-by: Ronnie Sahlberg <redacted> Signed-off-by: Steve French <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- fs/cifs/readdir.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c@@ -381,7 +381,7 @@ int get_symlink_reparse_path(char *full_ */ 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;
@@ -463,6 +463,27 @@ error_exit: 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) {