[PATCH 3/9] man/man2/statmount.2: Document STATMOUNT_FS_SUBTYPE

Document STATMOUNT_FS_SUBTYPE flag and the corresponding field
introduced by it.

STATMOUNT_FS_SUBTYPE retrieves the subtype of a file system, useful for
FUSE mounts (example: fuse.sshfs, where "sshfs" is the subtype).

This work is based on this commit message [1].

Link [1]:
<https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ed9d95f691c29748f21bc019de9566b698fdfab7>

Signed-off-by: Bhavik Sachdev <[email protected]>
---
 man/man2/statmount.2 | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/man/man2/statmount.2 b/man/man2/statmount.2
index 8ff01075d..462f6060e 100644
--- a/man/man2/statmount.2
+++ b/man/man2/statmount.2
@@ -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
@@ -259,6 +261,14 @@ .SS The returned information
 .I smbuf.mnt_ns_id
 The unique ID of the mount namespace the mount belongs to.
 .TP
+.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.
+.TP
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and
-- 
2.52.0