Commit d26c2ddd authored by Steve French's avatar Steve French
Browse files

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: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarAurelien Aptel <aaptel@suse.com>
Acked-by: default avatarPaulo Alcantara (SUSE) <pc@cjr.nz>
parent 343a1b77

fs/cifs/cifs_ioctl.h

+6 −0
Original line number Diff line number Diff line
@@ -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)

fs/cifs/cifsglob.h

+2 −0
Original line number Diff line number Diff line
@@ -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 *);

fs/cifs/ioctl.c

+16 −0
Original line number Diff line number Diff line
@@ -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;

fs/cifs/smb2ops.c

+62 −0
Original line number Diff line number Diff line
@@ -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(&notify, 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,

fs/cifs/smb2pdu.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

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