From d26c2ddd33569667e3eeb577c4c1d966ca9192e2 Mon Sep 17 00:00:00 2001 From: Steve French Date: Thu, 6 Feb 2020 06:00:14 -0600 Subject: 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 Reviewed-by: Aurelien Aptel Acked-by: Paulo Alcantara (SUSE) --- 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..baa825f4cec0 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); -- cgit