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7656 unlinking directory on tmpfs can cause kernel panic

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          --- old/usr/src/man/man2/unlink.2
          +++ new/usr/src/man/man2/unlink.2
   1    1  '\" te
   2    2  .\" Copyright (c) 2007, Sun Microsystems, Inc.  All Rights Reserved.
   3    3  .\" Copyright 1989 AT&T
   4    4  .\" Portions Copyright (c) 1992, X/Open Company Limited  All Rights Reserved.
        5 +.\" Copyright 2016 RackTop Systems.
   5    6  .\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at
   6    7  .\"
   7    8  .\" The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at
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   9   10  .\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
  10   11  .\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or  See the License for the specific language governing permissions and limitations under the License.
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  12      -.TH UNLINK 2 "May 18, 2007"
       13 +.TH UNLINK 2 "Dec 15, 2016"
  13   14  .SH NAME
  14   15  unlink, unlinkat \- remove directory entry
  15   16  .SH SYNOPSIS
  16   17  .LP
  17   18  .nf
  18   19  #include <unistd.h>
  19   20  
  20   21  \fBint\fR \fBunlink\fR(\fBconst char *\fR\fIpath\fR);
  21   22  .fi
  22   23  
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  54   55  .LP
  55   56  When the file's link count becomes 0 and no process has the file open, the
  56   57  space occupied by the file will be freed and the file is no longer accessible.
  57   58  If one or more processes have the file open when the last link is removed, the
  58   59  link is removed before \fBunlink()\fR or \fBunlinkat()\fR returns, but the
  59   60  removal of the file contents is postponed until all references to the file are
  60   61  closed.
  61   62  .sp
  62   63  .LP
  63   64  If the \fIpath\fR argument is a directory and the filesystem supports
  64      -\fBunlink()\fR and \fBunlinkat()\fR on directories, the directory is unlinked
  65      -from its parent with no cleanup being performed.  In UFS, the disconnected
  66      -directory will be found the next time the filesystem is checked with
  67      -\fBfsck\fR(1M). The \fBunlink()\fR and \fBunlinkat()\fR functions will not fail
  68      -simply because a directory is not empty. The user with appropriate privileges
  69      -can orphan a non-empty directory without generating an error message.
       65 +\fBunlink()\fR and \fBunlinkat()\fR on directories the behaviour is dependent
       66 +on the filesystem.
  70   67  .sp
  71   68  .LP
  72   69  If the \fIpath\fR argument is a directory and the filesystem does not support
  73   70  \fBunlink()\fR and \fBunlink()\fR on directories (for example, ZFS), the call
  74   71  will fail with \fBerrno\fR set to \fBEPERM\fR.
  75   72  .sp
  76   73  .LP
  77   74  Upon successful completion, \fBunlink()\fR and \fBunlinkat()\fR will mark for
  78   75  update the \fBst_ctime\fR and \fBst_mtime\fR fields of the parent directory.
  79   76  If the file's link count is not 0, the \fBst_ctime\fR field of the file will be
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