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From: Steve French <smfrench@gmail.com>
To: CIFS <linux-cifs@vger.kernel.org>
Subject: [CIFS][PATCH] Add SMB3 Change Notify
Date: Thu, 6 Feb 2020 06:29:04 -0600	[thread overview]
Message-ID: <CAH2r5mtQRVX3_-_sVjvigRSv2LpSoUBQo7YeY5v0nXm7BGaDig@mail.gmail.com> (raw)

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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

[-- Attachment #2: 0001-cifs-add-SMB3-change-notification-support.patch --]
[-- Type: text/x-patch, Size: 7051 bytes --]

From ccd073542ccc436c05afc6feb3c2b42ca2318c68 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
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@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
---
 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(&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,
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


             reply	other threads:[~2020-02-06 12:29 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-06 12:29 Steve French [this message]
2020-02-10 11:31 ` [CIFS][PATCH] Add SMB2? Change Notify L Walsh
2020-02-10 14:30   ` Steve French
2020-02-12 23:32     ` [CIFS][PATCH] Add SMB3/Win10-only " L Walsh
2020-02-13  4:43       ` Steve French

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