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cifs: do not send close in compound create+close requests
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commit 04ad69c upstream.

In case of interrupted syscalls, prevent sending CLOSE commands for
compound CREATE+CLOSE requests by introducing an
CIFS_CP_CREATE_CLOSE_OP flag to indicate lower layers that it should
not send a CLOSE command to the MIDs corresponding the compound
CREATE+CLOSE request.

A simple reproducer:

    #!/bin/bash

    mount //server/share /mnt -o username=foo,password=***
    tc qdisc add dev eth0 root netem delay 450ms
    stat -f /mnt &>/dev/null & pid=$!
    sleep 0.01
    kill $pid
    tc qdisc del dev eth0 root
    umount /mnt

Before patch:

    ...
    6 0.256893470 192.168.122.2 → 192.168.122.15 SMB2 402 Create Request File: ;GetInfo Request FS_INFO/FileFsFullSizeInformation;Close Request
    7 0.257144491 192.168.122.15 → 192.168.122.2 SMB2 498 Create Response File: ;GetInfo Response;Close Response
    9 0.260798209 192.168.122.2 → 192.168.122.15 SMB2 146 Close Request File:
   10 0.260841089 192.168.122.15 → 192.168.122.2 SMB2 130 Close Response, Error: STATUS_FILE_CLOSED

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@pcacjr @gregkh
pcacjr authored and gregkh committed Mar 17, 2021
1 parent 310a1ff commit d308202
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Showing 6 changed files with 18 additions and 17 deletions.
11 changes: 6 additions & 5 deletions fs/cifs/cifsglob.h
View file
Expand Up @@ -256,7 +256,7 @@ struct smb_version_operations {
/* verify the message */
int (*check_message)(char *, unsigned int, struct TCP_Server_Info *);
bool (*is_oplock_break)(char *, struct TCP_Server_Info *);
int (*handle_cancelled_mid)(char *, struct TCP_Server_Info *);
int (*handle_cancelled_mid)(struct mid_q_entry *, struct TCP_Server_Info *);
void (*downgrade_oplock)(struct TCP_Server_Info *server,
struct cifsInodeInfo *cinode, __u32 oplock,
unsigned int epoch, bool *purge_cache);
Expand Down Expand Up @@ -1785,10 +1785,11 @@ static inline bool is_retryable_error(int error)
#define CIFS_NO_RSP_BUF 0x040 /* no response buffer required */

/* Type of request operation */
#define CIFS_ECHO_OP 0x080 /* echo request */
#define CIFS_OBREAK_OP 0x0100 /* oplock break request */
#define CIFS_NEG_OP 0x0200 /* negotiate request */
#define CIFS_OP_MASK 0x0380 /* mask request type */
#define CIFS_ECHO_OP 0x080 /* echo request */
#define CIFS_OBREAK_OP 0x0100 /* oplock break request */
#define CIFS_NEG_OP 0x0200 /* negotiate request */
#define CIFS_CP_CREATE_CLOSE_OP 0x0400 /* compound create+close request */
#define CIFS_OP_MASK 0x0780 /* mask request type */

#define CIFS_HAS_CREDITS 0x0400 /* already has credits */
#define CIFS_TRANSFORM_REQ 0x0800 /* transform request before sending */
Expand Down
1 change: 1 addition & 0 deletions fs/cifs/smb2inode.c
View file
Expand Up @@ -358,6 +358,7 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
if (cfile)
goto after_close;
/* Close */
flags |= CIFS_CP_CREATE_CLOSE_OP;
rqst[num_rqst].rq_iov = &vars->close_iov[0];
rqst[num_rqst].rq_nvec = 1;
rc = SMB2_close_init(tcon, server,
Expand Down
8 changes: 4 additions & 4 deletions fs/cifs/smb2misc.c
View file
Expand Up @@ -835,14 +835,14 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid,
}

int
smb2_handle_cancelled_mid(char *buffer, struct TCP_Server_Info *server)
smb2_handle_cancelled_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server)
{
struct smb2_sync_hdr *sync_hdr = (struct smb2_sync_hdr *)buffer;
struct smb2_create_rsp *rsp = (struct smb2_create_rsp *)buffer;
struct smb2_sync_hdr *sync_hdr = mid->resp_buf;
struct smb2_create_rsp *rsp = mid->resp_buf;
struct cifs_tcon *tcon;
int rc;

if (sync_hdr->Command != SMB2_CREATE ||
if ((mid->optype & CIFS_CP_CREATE_CLOSE_OP) || sync_hdr->Command != SMB2_CREATE ||
sync_hdr->Status != STATUS_SUCCESS)
return 0;

Expand Down
10 changes: 5 additions & 5 deletions fs/cifs/smb2ops.c
View file
Expand Up @@ -1137,7 +1137,7 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
struct TCP_Server_Info *server = cifs_pick_channel(ses);
__le16 *utf16_path = NULL;
int ea_name_len = strlen(ea_name);
int flags = 0;
int flags = CIFS_CP_CREATE_CLOSE_OP;
int len;
struct smb_rqst rqst[3];
int resp_buftype[3];
Expand Down Expand Up @@ -1515,7 +1515,7 @@ smb2_ioctl_query_info(const unsigned int xid,
struct smb_query_info qi;
struct smb_query_info __user *pqi;
int rc = 0;
int flags = 0;
int flags = CIFS_CP_CREATE_CLOSE_OP;
struct smb2_query_info_rsp *qi_rsp = NULL;
struct smb2_ioctl_rsp *io_rsp = NULL;
void *buffer = NULL;
Expand Down Expand Up @@ -2482,7 +2482,7 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
{
struct cifs_ses *ses = tcon->ses;
struct TCP_Server_Info *server = cifs_pick_channel(ses);
int flags = 0;
int flags = CIFS_CP_CREATE_CLOSE_OP;
struct smb_rqst rqst[3];
int resp_buftype[3];
struct kvec rsp_iov[3];
Expand Down Expand Up @@ -2880,7 +2880,7 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
unsigned int sub_offset;
unsigned int print_len;
unsigned int print_offset;
int flags = 0;
int flags = CIFS_CP_CREATE_CLOSE_OP;
struct smb_rqst rqst[3];
int resp_buftype[3];
struct kvec rsp_iov[3];
Expand Down Expand Up @@ -3062,7 +3062,7 @@ smb2_query_reparse_tag(const unsigned int xid, struct cifs_tcon *tcon,
struct cifs_open_parms oparms;
struct cifs_fid fid;
struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
int flags = 0;
int flags = CIFS_CP_CREATE_CLOSE_OP;
struct smb_rqst rqst[3];
int resp_buftype[3];
struct kvec rsp_iov[3];
Expand Down
3 changes: 1 addition & 2 deletions fs/cifs/smb2proto.h
View file
Expand Up @@ -246,8 +246,7 @@ extern int SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
extern int smb2_handle_cancelled_close(struct cifs_tcon *tcon,
__u64 persistent_fid,
__u64 volatile_fid);
extern int smb2_handle_cancelled_mid(char *buffer,
struct TCP_Server_Info *server);
extern int smb2_handle_cancelled_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server);
void smb2_cancelled_close_fid(struct work_struct *work);
extern int SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,
u64 persistent_file_id, u64 volatile_file_id,
Expand Down
2 changes: 1 addition & 1 deletion fs/cifs/transport.c
View file
Expand Up @@ -101,7 +101,7 @@ static void _cifs_mid_q_entry_release(struct kref *refcount)
if (midEntry->resp_buf && (midEntry->mid_flags & MID_WAIT_CANCELLED) &&
midEntry->mid_state == MID_RESPONSE_RECEIVED &&
server->ops->handle_cancelled_mid)
server->ops->handle_cancelled_mid(midEntry->resp_buf, server);
server->ops->handle_cancelled_mid(midEntry, server);

midEntry->mid_state = MID_FREE;
atomic_dec(&midCount);
Expand Down

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