Thread (29 messages) 29 messages, 5 authors, 2026-03-06

[PATCH v2 1/4] man/man2/statmount.2: Document STATMOUNT_{UIDMAP,GIDMAP}

From: Bhavik Sachdev <hidden>
Date: 2026-02-23 14:13:01
Subsystem: the rest · Maintainer: Linus Torvalds

Document the STATMOUNT_{UIDMAP,GIDMAP} flags and the corresponding
fields introduced by them. Most of this is based on the commit message
provided here [1].

Link [1]:
<https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=37c4a9590e1efcae7749682239fc22a330d2d325>

Signed-off-by: Bhavik Sachdev <redacted>
Message-ID: [off-list ref]
---
Hey Alex!

Hopefully this is what you wanted!

Thanks,
Bhavik

 man/man2/statmount.2 | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
diff --git a/man/man2/statmount.2 b/man/man2/statmount.2
index f8d2302ef..f5a3721eb 100644
--- a/man/man2/statmount.2
+++ b/man/man2/statmount.2
@@ -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_{num,array} */
 STATMOUNT_OPT_SEC_ARRAY	/* Want/got opt_sec_{num,array} */
+STATMOUNT_MNT_UIDMAP	/* Want/got uidmap... */
+STATMOUNT_MNT_GIDMAP	/* Want/got gidmap... */
 .TE
 .in
 .P
@@ -302,6 +308,38 @@ .SS The returned information
 buffer that contains security options separated by null bytes.
 They can be iterated over with the help of
 .IR smbuf.opt_sec_num .
+.TP
+.IR smbuf.mnt_uidmap_num " (since Linux 6.15)"
+The number of uid mappings applied on the mount.
+If
+.I smbuf.mask
+has STATMOUNT_UIDMAP set and this field is 0,
+the mount is not an idmapped mount.
+.TP
+.IR smbuf.mnt_uidmap " (since Linux 6.15)"
+The offset to the location in the
+.I smbuf.str
+buffer that contains uid mappings as consecutive null-terminated strings.
+They can be iterated over with the help of
+.IR smbuf.mnt_uidmap_num .
+The whole range of uid mappings must be resolvable in the user namespace
+of the caller.
+.TP
+.IR smbuf.mnt_gidmap_num " (since Linux 6.15)"
+The number of gid mappings applied on the mount.
+If
+.I smbuf.mask
+has STATMOUNT_GIDMAP set and this field is 0,
+the mount is not an idmapped mount.
+.TP
+.IR smbuf.mnt_gidmap " (since Linux 6.15)"
+The offset to the location in the
+.I smbuf.str
+buffer that contains gid mappings as consecutive null-terminated strings.
+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 user namespace
+of the caller.
 .SH RETURN VALUE
 On success, zero is returned.
 On error, \-1 is returned, and
-- 
2.53.0
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