Commit 3998f0b8 authored by Ronnie Sahlberg's avatar Ronnie Sahlberg Committed by Steve French
Browse files

cifs: Do not leak EDEADLK to dgetents64 for STATUS_USER_SESSION_DELETED 



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: default avatarXiaoli Feng <xifeng@redhat.com>
Signed-off-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 332c404a

fs/cifs/readdir.c

+22 −1
Original line number Diff line number Diff line
@@ -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)

{