A commonly used SMB3 feature is change notification, allowing an
app to be notified about changes to a directory. The SMB3
Notify request blocks until the server detects a change to that
directory or its contents that matches the completion flags
that were passed in and the "watch_tree" flag (which indicates
whether subdirectories under this directory should be also
included). See MS-SMB2 2.2.35 for additional detail.
To use this simply pass in the following structure to ioctl:
struct __attribute__((__packed__)) smb3_notify {
uint32_t completion_filter;
bool watch_tree;
} __packed;
using CIFS_IOC_NOTIFY 0x4005cf09
or equivalently _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)
SMB3 change notification is supported by all major servers.
The ioctl will block until the server detects a change to that
directory or its subdirectories (if watch_tree is set).
--
Thanks,
Steve
From ccd073542ccc436c05afc6feb3c2b42ca2318c68 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Thu, 6 Feb 2020 06:00:14 -0600
Subject: [PATCH] cifs: add SMB3 change notification support
A commonly used SMB3 feature is change notification, allowing an
app to be notified about changes to a directory. The SMB3
Notify request blocks until the server detects a change to that
directory or its contents that matches the completion flags
that were passed in and the "watch_tree" flag (which indicates
whether subdirectories under this directory should be also
included). See MS-SMB2 2.2.35 for additional detail.
To use this simply pass in the following structure to ioctl:
struct __attribute__((__packed__)) smb3_notify {
uint32_t completion_filter;
bool watch_tree;
} __packed;
using CIFS_IOC_NOTIFY 0x4005cf09
or equivalently _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)
SMB3 change notification is supported by all major servers.
The ioctl will block until the server detects a change to that
directory or its subdirectories (if watch_tree is set).
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Reviewed-by: Aurelien Aptel <aaptel@xxxxxxxx>
---
fs/cifs/cifs_ioctl.h | 6 +++++
fs/cifs/cifsglob.h | 2 ++
fs/cifs/ioctl.c | 16 ++++++++++++
fs/cifs/smb2ops.c | 62 ++++++++++++++++++++++++++++++++++++++++++++
fs/cifs/smb2pdu.c | 1 +
5 files changed, 87 insertions(+)
diff --git a/fs/cifs/cifs_ioctl.h b/fs/cifs/cifs_ioctl.h
index 0f0dc1c1fe41..153d5c842a9b 100644
--- a/fs/cifs/cifs_ioctl.h
+++ b/fs/cifs/cifs_ioctl.h
@@ -65,6 +65,11 @@ struct smb3_key_debug_info {
__u8 smb3decryptionkey[SMB3_SIGN_KEY_SIZE];
} __packed;
+struct smb3_notify {
+ __u32 completion_filter;
+ bool watch_tree;
+} __packed;
+
#define CIFS_IOCTL_MAGIC 0xCF
#define CIFS_IOC_COPYCHUNK_FILE _IOW(CIFS_IOCTL_MAGIC, 3, int)
#define CIFS_IOC_SET_INTEGRITY _IO(CIFS_IOCTL_MAGIC, 4)
@@ -72,3 +77,4 @@ struct smb3_key_debug_info {
#define CIFS_ENUMERATE_SNAPSHOTS _IOR(CIFS_IOCTL_MAGIC, 6, struct smb_snapshot_array)
#define CIFS_QUERY_INFO _IOWR(CIFS_IOCTL_MAGIC, 7, struct smb_query_info)
#define CIFS_DUMP_KEY _IOWR(CIFS_IOCTL_MAGIC, 8, struct smb3_key_debug_info)
+#define CIFS_IOC_NOTIFY _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 1205041fd966..de82cfa44b1a 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -431,6 +431,8 @@ struct smb_version_operations {
struct cifsFileInfo *src_file);
int (*enum_snapshots)(const unsigned int xid, struct cifs_tcon *tcon,
struct cifsFileInfo *src_file, void __user *);
+ int (*notify)(const unsigned int xid, struct file *pfile,
+ void __user *pbuf);
int (*query_mf_symlink)(unsigned int, struct cifs_tcon *,
struct cifs_sb_info *, const unsigned char *,
char *, unsigned int *);
diff --git a/fs/cifs/ioctl.c b/fs/cifs/ioctl.c
index e4c935026d5e..4a73e63c4d43 100644
--- a/fs/cifs/ioctl.c
+++ b/fs/cifs/ioctl.c
@@ -169,6 +169,7 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
unsigned int xid;
struct cifsFileInfo *pSMBFile = filep->private_data;
struct cifs_tcon *tcon;
+ struct cifs_sb_info *cifs_sb;
__u64 ExtAttrBits = 0;
__u64 caps;
@@ -299,6 +300,21 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
else
rc = 0;
break;
+ case CIFS_IOC_NOTIFY:
+ if (!S_ISDIR(inode->i_mode)) {
+ /* Notify can only be done on directories */
+ rc = -EOPNOTSUPP;
+ break;
+ }
+ cifs_sb = CIFS_SB(inode->i_sb);
+ tcon = tlink_tcon(cifs_sb_tlink(cifs_sb));
+ if (tcon && tcon->ses->server->ops->notify) {
+ rc = tcon->ses->server->ops->notify(xid,
+ filep, (void __user *)arg);
+ cifs_dbg(FYI, "ioctl notify rc %d\n", rc);
+ } else
+ rc = -EOPNOTSUPP;
+ break;
default:
cifs_dbg(FYI, "unsupported ioctl\n");
break;
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index ac6628e28b12..5928f3467c13 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2045,6 +2045,66 @@ smb3_enum_snapshots(const unsigned int xid, struct cifs_tcon *tcon,
return rc;
}
+
+
+static int
+smb3_notify(const unsigned int xid, struct file *pfile,
+ void __user *ioc_buf)
+{
+ struct smb3_notify notify;
+ struct dentry *dentry = pfile->f_path.dentry;
+ struct inode *inode = file_inode(pfile);
+ struct cifs_sb_info *cifs_sb;
+ struct cifs_open_parms oparms;
+ struct cifs_fid fid;
+ struct cifs_tcon *tcon;
+ unsigned char *path = NULL;
+ __le16 *utf16_path = NULL;
+ u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
+ int rc = 0;
+
+ path = build_path_from_dentry(dentry);
+ if (path == NULL)
+ return -ENOMEM;
+
+ cifs_sb = CIFS_SB(inode->i_sb);
+
+ utf16_path = cifs_convert_path_to_utf16(path + 1, cifs_sb);
+ if (utf16_path == NULL) {
+ rc = -ENOMEM;
+ goto notify_exit;
+ }
+
+ if (copy_from_user(¬ify, ioc_buf, sizeof(struct smb3_notify))) {
+ rc = -EFAULT;
+ goto notify_exit;
+ }
+
+ tcon = cifs_sb_master_tcon(cifs_sb);
+ oparms.tcon = tcon;
+ oparms.desired_access = FILE_READ_ATTRIBUTES;
+ oparms.disposition = FILE_OPEN;
+ oparms.create_options = cifs_create_options(cifs_sb, 0);
+ oparms.fid = &fid;
+ oparms.reconnect = false;
+
+ rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
+ if (rc)
+ goto notify_exit;
+
+ rc = SMB2_change_notify(xid, tcon, fid.persistent_fid, fid.volatile_fid,
+ notify.watch_tree, notify.completion_filter);
+
+ SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
+
+ cifs_dbg(FYI, "change notify for path %s rc %d\n", path, rc);
+
+notify_exit:
+ kfree(path);
+ kfree(utf16_path);
+ return rc;
+}
+
static int
smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
const char *path, struct cifs_sb_info *cifs_sb,
@@ -4841,6 +4901,7 @@ struct smb_version_operations smb30_operations = {
.dir_needs_close = smb2_dir_needs_close,
.fallocate = smb3_fallocate,
.enum_snapshots = smb3_enum_snapshots,
+ .notify = smb3_notify,
.init_transform_rq = smb3_init_transform_rq,
.is_transform_hdr = smb3_is_transform_hdr,
.receive_transform = smb3_receive_transform,
@@ -4951,6 +5012,7 @@ struct smb_version_operations smb311_operations = {
.dir_needs_close = smb2_dir_needs_close,
.fallocate = smb3_fallocate,
.enum_snapshots = smb3_enum_snapshots,
+ .notify = smb3_notify,
.init_transform_rq = smb3_init_transform_rq,
.is_transform_hdr = smb3_is_transform_hdr,
.receive_transform = smb3_receive_transform,
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1a732ff71de4..47cce0bd1afe 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3363,6 +3363,7 @@ SMB2_notify_init(const unsigned int xid, struct smb_rqst *rqst,
req->PersistentFileId = persistent_fid;
req->VolatileFileId = volatile_fid;
+ /* See note 354 of MS-SMB2, 64K max */
req->OutputBufferLength =
cpu_to_le32(SMB2_MAX_BUFFER_SIZE - MAX_SMB2_HDR_SIZE);
req->CompletionFilter = cpu_to_le32(completion_filter);
--
2.20.1
