[PATCH] fix descriptions for AT_NO_AUTOMOUNT

["Pádraig Brady" <P@draigBrady.com>]

fstatat(..., AT_NO_AUTOMOUNT) has had the following history in Linux:
  v2.6.37-7314-g6f45b65672c8
    add AT_NO_AUTOMOUNT and fstatat honors it
  v3.1-rc7-68-gb6c8069d3577
    ignore AT_NO_AUTOMOUNT since default operation now less eagerly mounts
  v4.10-11255-ga528d35e8bfc
    adds statx which reinstated 2.6.38 behavior for fstatat (not released)
  v4.11-rc7-14-gdeccf497d804
    adjust fstatat so that AT_NO_AUTOMOUNT always specified (to statx)

* man2/stat.2:
Adjust AT_NO_AUTOMOUNT description for fstatat.2 as per the above,
to indicate AT_NO_AUTOMOUNT should be avoided with fstatat() since
it's ignored since 3.1 and implied since 4.11.

Don't mention commit v4.13-9318-g42f461482178 as it was reverted,
and moot anyway since we can't adjust AT_NO_AUTOMOUNT since 3.1.

* man2/statx.2:
Mention that stat(), lstat(), and fstatat() imply AT_NO_AUTOMOUNT.

Signed-off-by: Pádraig Brady <P@draigBrady.com>
---
 man2/stat.2  | 31 +++----------------------------
 man2/statx.2 | 18 +++++++++++++++---
 2 files changed, 18 insertions(+), 31 deletions(-)

diff --git a/man2/stat.2 b/man2/stat.2
index 016c1f47d..9000b2ca6 100644
--- a/man2/stat.2
+++ b/man2/stat.2
@@ -319,34 +319,9 @@ to obtain its definition.
 .TP
 .BR AT_NO_AUTOMOUNT " (since Linux 2.6.38)"
 Don't automount the terminal ("basename") component of
-.I pathname
-if it is a directory that is an automount point.
-This allows the caller to gather attributes of an automount point
-(rather than the location it would mount).
-Since Linux 4.14,
-.\" commit 42f46148217865a545e129612075f3d828a2c4e4
-also don't instantiate a nonexistent name in an
-on-demand directory such as used for automounter indirect maps.
-This
-flag has no effect if the mount point has already been mounted over.
-.IP
-Both
-.BR stat ()
-and
-.BR lstat ()
-act as though
-.B AT_NO_AUTOMOUNT
-was set.
-.IP
-The
-.B AT_NO_AUTOMOUNT
-can be used in tools that scan directories
-to prevent mass-automounting of a directory of automount points.
-.IP
-This flag is Linux-specific; define
-.B _GNU_SOURCE
-.\" Before glibc 2.16, defining _ATFILE_SOURCE sufficed
-to obtain its definition.
+.I pathname.
+Since Linux 3.1 this flag is ignored.
+Since Linux 4.11 this flag is implied.
 .TP
 .B AT_SYMLINK_NOFOLLOW
 If
diff --git a/man2/statx.2 b/man2/statx.2
index 04b3e5075..d4e638756 100644
--- a/man2/statx.2
+++ b/man2/statx.2
@@ -195,11 +195,23 @@ Don't automount the terminal ("basename") component of
 if it is a directory that is an automount point.
 This allows the caller to gather attributes of an automount point
 (rather than the location it would mount).
-This flag can be used in tools that scan directories
-to prevent mass-automounting of a directory of automount points.
+This
+flag has no effect if the mount point has already been mounted over.
+.IP
 The
 .B AT_NO_AUTOMOUNT
-flag has no effect if the mount point has already been mounted over.
+flag can be used in tools that scan directories
+to prevent mass-automounting of a directory of automount points.
+.IP
+All of
+.BR stat () ,
+.BR lstat () ,
+and
+.BR fstatat ()
+act as though
+.B AT_NO_AUTOMOUNT
+was set.
+.IP
 This flag is Linux-specific; define
 .B _GNU_SOURCE
 .\" Before glibc 2.16, defining _ATFILE_SOURCE sufficed
-- 
2.34.1