svn commit: r356434 - head/sbin/fsck_msdosfs

[Xin LI]

Author: delphij
Date: Tue Jan  7 04:33:14 2020
New Revision: 356434
URL: https://svnweb.freebsd.org/changeset/base/356434

Log:
  fsck_msdosfs.8: document -M.
  
  Reported by:	mckusick
  Reviewed by:	mckusick, emaste, bcr
  MFC after:	28 days
  X-MFC-with:	r356313
  Differential Revision:	https://reviews.freebsd.org/D23049

Modified:
  head/sbin/fsck_msdosfs/fsck_msdosfs.8

Modified: head/sbin/fsck_msdosfs/fsck_msdosfs.8
==============================================================================
--- head/sbin/fsck_msdosfs/fsck_msdosfs.8	Tue Jan  7 04:30:49 2020	(r356433)
+++ head/sbin/fsck_msdosfs/fsck_msdosfs.8	Tue Jan  7 04:33:14 2020	(r356434)
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 3, 2016
+.Dd January 6, 2020
 .Dt FSCK_MSDOSFS 8
 .Os
 .Sh NAME
@@ -37,7 +37,7 @@
 .Op Fl Cf
 .Ar filesystem ...
 .Nm
-.Op Fl Cny
+.Op Fl CMny
 .Ar filesystem ...
 .Sh DESCRIPTION
 The
@@ -84,6 +84,21 @@ which seeks to determine whether the file system needs
 immediately in foreground, or if its cleaning can be deferred to background.
 FAT (MS-DOS) file systems must always be cleaned in the foreground.
 A non-zero exit code is always returned for this option.
+.It Fl M
+Causes
+.Nm
+to not use
+.Xr mmap 2
+when checking a FAT32 file system.
+This option is mainly for debugging purposes and is not normally necessary.
+The
+.Nm
+utility will automatically fall back to use a simple LRU cache of 4 MiB
+when it failed to perform
+.Xr mmap 2 ,
+or when
+.Fl M
+is specified.
 .It Fl f
 Force
 .Nm