man/man2/statmount.2: Document New Features

index cdc96da92..f5c4da122 100644
@@ -23,9 +23,10 @@ .SH SYNOPSIS
 .P
 .EX
 .B struct mnt_id_req {
-.BR "    __u32  size;" "    /* sizeof(struct mnt_id_req) */"
-.BR "    __u64  mnt_id;" "  /* The mnt_id being queried */"
-.BR "    __u64  param;" "   /* An ORed combination of the STATMOUNT_ constants */"
+.BR "    __u32  size;" "        /* sizeof(struct mnt_id_req) */"
+.BR "    __u64  mnt_id;" "      /* The mnt_id being queried */"
+.BR "    __u64  param;" "       /* An ORed combination of the STATMOUNT_ constants */"
+.BR "    __u32  mnt_ns_id;" "   /* The id of mnt_ns to query the mnt_id in */"
 .B };
 .P
 .B struct statmount {

@@ -47,6 +48,7 @@ .SH SYNOPSIS
 .B "    __u64  propagate_from;"
 .B "    __u32  mnt_root;"
 .B "    __u32  mnt_point;"
+.B "    __u64  mnt_ns_id;"
 .B "    char   str[];"
 .B };
 .EE

@@ -59,6 +61,9 @@ .SH SYNOPSIS
 .SH DESCRIPTION
 To access a mount's status,
 the caller must have CAP_SYS_ADMIN in the user namespace.
+In case of accessing a mount in a foreign mount namespace (specified via
+.IR req.mnt_ns_id ),
+the foreign mount namespace should be child of the current namespace.
 .P
 This function returns information about a mount,
 storing it in the buffer pointed to by

@@ -102,6 +107,7 @@ .SS The mnt_id_req structure
 STATMOUNT_MNT_ROOT	/* Want/got mnt_root  */
 STATMOUNT_MNT_POINT	/* Want/got mnt_point */
 STATMOUNT_FS_TYPE	/* Want/got fs_type */
+STATMOUNT_MNT_NS_ID	/* Want/got mnt_ns_id */
 .TE
 .in
 .P

@@ -130,6 +136,13 @@ .SS The mnt_id_req structure
 as one or more bits may,
 in the future,
 be used to specify an extension to the buffer.
+.P
+.I req.mnt_ns_id
+can be obtained from
+.B NS_GET_MNTNS_ID
+.BR ioctl (2)
+operation and is used to specify a foreign mount namespace in which to query
+.IR req.mnt_id .
 .SS The returned information
 The status information for the target mount is returned in the
 .I statmount

@@ -232,6 +245,9 @@ .SS The returned information
 relative to the current root (ie if you are in a
 .BR chroot ).
 It is a null-terminated string.
+.TP
+.I smbuf.mnt_ns_id
+The unique ID of the mount namespace the mount belongs to.
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and

index f5c4da122..fee37069a 100644
@@ -31,6 +31,7 @@ .SH SYNOPSIS
 .P
 .B struct statmount {
 .B "    __u32  size;"
+.B "    __u32  mnt_opts;"
 .B "    __u64  mask;"
 .B "    __u32  sb_dev_major;"
 .B "    __u32  sb_dev_minor;"

@@ -108,6 +109,7 @@ .SS The mnt_id_req structure
 STATMOUNT_MNT_POINT	/* Want/got mnt_point */
 STATMOUNT_FS_TYPE	/* Want/got fs_type */
 STATMOUNT_MNT_NS_ID	/* Want/got mnt_ns_id */
+STATMOUNT_MNT_OPTS	/* Want/got mnt_opts */
 .TE
 .in
 .P

@@ -159,6 +161,13 @@ .SS The returned information
 structure,
 including any of the strings fields that were filled.
 .TP
+.I smbuf.mnt_opts
+The offset to the location in the
+.I smbuf.str
+buffer that contains a comma separated list of mount options,
+similiar to those in /proc/[pid]/mountinfo.
+It is a null-terminated string.
+.TP
 .I smbuf.mask
 The ORed combination of
 .BI STATMOUNT_ *

index fee37069a..b24b4a5fd 100644
@@ -50,6 +50,7 @@ .SH SYNOPSIS
 .B "    __u32  mnt_root;"
 .B "    __u32  mnt_point;"
 .B "    __u64  mnt_ns_id;"
+.B "    __u32  fs_subtype;"
 .B "    char   str[];"
 .B };
 .EE

@@ -110,6 +111,7 @@ .SS The mnt_id_req structure
 STATMOUNT_FS_TYPE	/* Want/got fs_type */
 STATMOUNT_MNT_NS_ID	/* Want/got mnt_ns_id */
 STATMOUNT_MNT_OPTS	/* Want/got mnt_opts */
+STATMOUNT_FS_SUBTYPE	/* Want/got fs_subtype */
 .TE
 .in
 .P

@@ -257,6 +259,13 @@ .SS The returned information
 .TP
 .I smbuf.mnt_ns_id
 The unique ID of the mount namespace the mount belongs to.
+.TP
+.I smbuf.fs_subtype
+The offset to the location in the
+.I smbuf.str
+buffer that contains the string representation of the file system subtype.
+This is particularly useful for disambiguating FUSE mounts.
+It is a null-terminated string.
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and

index b24b4a5fd..dd1f1f17d 100644
@@ -51,6 +51,7 @@ .SH SYNOPSIS
 .B "    __u32  mnt_point;"
 .B "    __u64  mnt_ns_id;"
 .B "    __u32  fs_subtype;"
+.B "    __u32  sb_source;"
 .B "    char   str[];"
 .B };
 .EE

@@ -112,6 +113,7 @@ .SS The mnt_id_req structure
 STATMOUNT_MNT_NS_ID	/* Want/got mnt_ns_id */
 STATMOUNT_MNT_OPTS	/* Want/got mnt_opts */
 STATMOUNT_FS_SUBTYPE	/* Want/got fs_subtype */
+STATMOUNT_SB_SOURCE	/* Want/got sb_source */
 .TE
 .in
 .P

@@ -266,6 +268,12 @@ .SS The returned information
 buffer that contains the string representation of the file system subtype.
 This is particularly useful for disambiguating FUSE mounts.
 It is a null-terminated string.
+.TP
+.I smbuf.sb_source
+The offset to the location in the
+.I smbuf.str
+the source for the mount.
+It is a null-terminated string.
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and

index dd1f1f17d..e47af22c3 100644
@@ -52,6 +52,8 @@ .SH SYNOPSIS
 .B "    __u64  mnt_ns_id;"
 .B "    __u32  fs_subtype;"
 .B "    __u32  sb_source;"
+.B "    __u32  opt_num;"
+.B "    __u32  opt_array;"
 .B "    char   str[];"
 .B };
 .EE

@@ -114,6 +116,7 @@ .SS The mnt_id_req structure
 STATMOUNT_MNT_OPTS	/* Want/got mnt_opts */
 STATMOUNT_FS_SUBTYPE	/* Want/got fs_subtype */
 STATMOUNT_SB_SOURCE	/* Want/got sb_source */
+STATMOUNT_OPT_ARRAY	/* Want/got opt_... */
 .TE
 .in
 .P

@@ -274,6 +277,16 @@ .SS The returned information
 .I smbuf.str
 the source for the mount.
 It is a null-terminated string.
+.TP
+.I smbuf.opt_num
+The number of filesystem options set on the mount.
+.TP
+.I smbuf.opt_array
+The offset to the location in the
+.I smbuf.str
+buffer that contains file system options separated by null bytes.
+They can be iterated over the help of
+.IR smbuf.opt_num .
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and

index e47af22c3..b7acde8f4 100644
@@ -54,6 +54,8 @@ .SH SYNOPSIS
 .B "    __u32  sb_source;"
 .B "    __u32  opt_num;"
 .B "    __u32  opt_array;"
+.B "    __u32  opt_sec_num;"
+.B "    __u32  opt_sec_array;"
 .B "    char   str[];"
 .B };
 .EE

@@ -117,6 +119,7 @@ .SS The mnt_id_req structure
 STATMOUNT_FS_SUBTYPE	/* Want/got fs_subtype */
 STATMOUNT_SB_SOURCE	/* Want/got sb_source */
 STATMOUNT_OPT_ARRAY	/* Want/got opt_... */
+STATMOUNT_OPT_SEC_ARRAY	/* Want/got opt_sec... */
 .TE
 .in
 .P

@@ -287,6 +290,15 @@ .SS The returned information
 buffer that contains file system options separated by null bytes.
 They can be iterated over the help of
 .IR smbuf.opt_num .
+.I smbuf.opt_sec_num
+The number of security options set on the mount.
+.TP
+.I smbuf.opt_sec_array
+The offset to the location in the
+.I smbuf.str
+buffer that contains security options separated by null bytes.
+They can be iterated over the help of
+.IR smbuf.opt_sec_num .
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and

index b7acde8f4..4da55eb38 100644
@@ -56,6 +56,10 @@ .SH SYNOPSIS
 .B "    __u32  opt_array;"
 .B "    __u32  opt_sec_num;"
 .B "    __u32  opt_sec_array;"
+.B "    __u32  mnt_uidmap_num;"
+.B "    __u32  mnt_uidmap;"
+.B "    __u32  mnt_gidmap_num;"
+.B "    __u32  mnt_gidmap;"
 .B "    char   str[];"
 .B };
 .EE

@@ -120,6 +124,8 @@ .SS The mnt_id_req structure
 STATMOUNT_SB_SOURCE	/* Want/got sb_source */
 STATMOUNT_OPT_ARRAY	/* Want/got opt_... */
 STATMOUNT_OPT_SEC_ARRAY	/* Want/got opt_sec... */
+STATMOUNT_MNT_UIDMAP	/* Want/got uidmap... */
+STATMOUNT_MNT_GIDMAP	/* Want/got gidmap... */
 .TE
 .in
 .P

@@ -299,6 +305,34 @@ .SS The returned information
 buffer that contains security options separated by null bytes.
 They can be iterated over the help of
 .IR smbuf.opt_sec_num .
+.TP
+.I smbuf.mnt_uidmap_num
+The number of uid mappings in case of an idmapped mount.
+If STATMOUNT_UIDMAP was not unset and this field is 0,
+the mount is not an idmapped mount.
+.TP
+.I smbuf.mnt_uidmap
+The offset to the location in the
+.I smbuf.str
+buffer that contains uid mappings as string array separated by null bytes.
+They can be iterated over with the help of
+.IR smbuf.mnt_uidmap_num .
+The whole range of uid mappings must be resolvable inthe caller's user
+namespace.
+.TP
+.I smbuf.mnt_gidmap_num
+The number of gid mappings in case of an idmapped mount.
+If STATMOUNT_GIDMAP was not unset and this field is 0,
+the mount is not an idmapped mount.
+.TP
+.I smbuf.mnt_gidmap
+The offset to the location in the
+.I smbuf.str
+buffer that contains uid mappings as string array separated by null bytes.
+They can be iterated over with the help of
+.IR smbuf.mnt_gidmap_num .
+The whole range of gid mappings must be resolvable in the caller's user
+namespace.
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and

index 4da55eb38..0b906a334 100644
@@ -60,6 +60,7 @@ .SH SYNOPSIS
 .B "    __u32  mnt_uidmap;"
 .B "    __u32  mnt_gidmap_num;"
 .B "    __u32  mnt_gidmap;"
+.B "    __u64  supported_mask;"
 .B "    char   str[];"
 .B };
 .EE

@@ -126,6 +127,7 @@ .SS The mnt_id_req structure
 STATMOUNT_OPT_SEC_ARRAY	/* Want/got opt_sec... */
 STATMOUNT_MNT_UIDMAP	/* Want/got uidmap... */
 STATMOUNT_MNT_GIDMAP	/* Want/got gidmap... */
+STATMOUNT_SUPPORTED_MASK	/* Want/got supported mask flags */
 .TE
 .in
 .P

@@ -333,6 +335,11 @@ .SS The returned information
 .IR smbuf.mnt_gidmap_num .
 The whole range of gid mappings must be resolvable in the caller's user
 namespace.
+.TP
+.I smbuf.supported_mask
+The ORed combination of
+.BI STATMOUNT_ *
+flags supported by the current kernel.
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and

index 0b906a334..e835eb0f6 100644
@@ -24,6 +24,7 @@ .SH SYNOPSIS
 .EX
 .B struct mnt_id_req {
 .BR "    __u32  size;" "        /* sizeof(struct mnt_id_req) */"
+.BR "    __u32  mnt_ns_fd;" "   /* fd of mnt_ns to query the mnt_id in */"
 .BR "    __u64  mnt_id;" "      /* The mnt_id being queried */"
 .BR "    __u64  param;" "       /* An ORed combination of the STATMOUNT_ constants */"
 .BR "    __u32  mnt_ns_id;" "   /* The id of mnt_ns to query the mnt_id in */"

@@ -74,7 +75,9 @@ .SH DESCRIPTION
 To access a mount's status,
 the caller must have CAP_SYS_ADMIN in the user namespace.
 In case of accessing a mount in a foreign mount namespace (specified via
-.IR req.mnt_ns_id ),
+.I req.mnt_ns_id
+or
+.IR req.mnt_ns_fd ),
 the foreign mount namespace should be child of the current namespace.
 .P
 This function returns information about a mount,

@@ -97,6 +100,15 @@ .SS The mnt_id_req structure
 it should always be set to
 .IR sizeof(struct\~mnt_id_req) .
 .P
+.I req.mnt_ns_fd
+can be obtained from
+.B PIDFD_GET_MNT_NAMESPACE
+.BR ioctl (2)
+operation or by opening a file descriptor to
+.IR /proc/[pid]/ns/mnt
+and is used to specify a foreign mount namespace in which to query
+.IR req.mnt_id .
+.P
 .I req.mnt_id
 can be obtained from either
 .BR statx (2)

@@ -365,6 +377,13 @@ .SH ERRORS
 .I req
 is of insufficient size to be utilized.
 .TP
+.B EINVAL
+Both
+.I req.mnt_ns_id
+and
+.I req.mnt_ns_fd
+were set.
+.TP
 .B E2BIG
 .I req
 is too large.

index e835eb0f6..484fec383 100644
@@ -24,7 +24,10 @@ .SH SYNOPSIS
 .EX
 .B struct mnt_id_req {
 .BR "    __u32  size;" "        /* sizeof(struct mnt_id_req) */"
-.BR "    __u32  mnt_ns_fd;" "   /* fd of mnt_ns to query the mnt_id in */"
+.BR "    union {"
+.BR "           __u32  mnt_ns_fd;" "   /* fd of mnt_ns to query the mnt_id in */"
+.BR "           __u32  mnt_fd;" "      /* fd on the mount being queried */"
+.BR "    };"
 .BR "    __u64  mnt_id;" "      /* The mnt_id being queried */"
 .BR "    __u64  param;" "       /* An ORed combination of the STATMOUNT_ constants */"
 .BR "    __u32  mnt_ns_id;" "   /* The id of mnt_ns to query the mnt_id in */"

@@ -89,7 +92,7 @@ .SH DESCRIPTION
 .I bufsize
 with the fields filled in as described below.
 .I flags
-must be 0.
+must either be 0 or STATMOUNT_BY_FD.
 .P
 (Note that reserved space and padding is omitted.)
 .SS The mnt_id_req structure

@@ -109,6 +112,24 @@ .SS The mnt_id_req structure
 and is used to specify a foreign mount namespace in which to query
 .IR req.mnt_id .
 .P
+.I req.mnt_fd
+is a file descriptor on a mount.
+If STATMOUNT_BY_FD flag is specified,
+.I req.mnt_id
+and
+.I req.mnt_ns_id
+are zeroed, the function will return information about the mount the fd is on.
+.P
+The fd can also be on a mount that has been lazily unmounted (see
+.BR umount2 (2)
+with
+.BR MNT_DETACH ).
+In this case,
+.BR STATMOUNT_MNT_POINT
+and
+.BR STATMOUNT_MNT_NS_ID
+will be unset, since an unmounted mount is no longer a part of the filesystem.
+.P
 .I req.mnt_id
 can be obtained from either
 .BR statx (2)

@@ -384,6 +405,16 @@ .SH ERRORS
 .I req.mnt_ns_fd
 were set.
 .TP
+.B EINVAL
+.I req.mnt_id
+or
+.I req.mnt_ns_id
+was specified alongside
+.IR req.mnt_fd .
+.TP
+.B EBADF
+.I req.mnt_fd
+is an invalid file descriptor.
 .B E2BIG
 .I req
 is too large.