From d66d1ed9c5f6fd7090c11b4fa153f5e029554b98 Mon Sep 17 00:00:00 2001
From: Bernhard Voelker <mail@bernhard-voelker.de>
Date: Tue, 30 Jan 2018 23:30:09 +0100
Subject: [PATCH] find: make -delete honour the -ignore_readdir_race option

* find/pred.c (pred_delete): Return true when the -ignore_readdir_race
option is active and unlinkat() came back with ENOENT.
* doc/find.texi (Option -ignore_readdir_race): Document the change.
(Action -delete): Likewise.
* find/find.1: Likewise.
* NEWS (Bug Fixes): Mention the fix.

For now, it seems a bit hard to add a proper test for this,
so the following shell snippet demonstrates the race:

  $ seq 10 | xargs touch
  $ env time -f 'find exit status: %x\nfind time: %e' \
      find -ignore_readdir_race -type f \
        -delete \
        -exec sh -c 'sleep $(basename {})' \; \
        -printf 'find deleted: %p\n' \
        & \
    sleep 20; \
    seq 10 | xargs rm -fv; \
    wait $!

Reported by Alexander Golubev in
https://savannah.gnu.org/bugs/?52981
---
 NEWS          |  4 ++++
 doc/find.texi | 15 ++++++++++++++-
 find/find.1   | 22 ++++++++++++++++++++++
 find/pred.c   |  6 ++++++
 4 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index 025132ec..2095adc1 100644
--- a/NEWS
+++ b/NEWS
@@ -54,6 +54,10 @@ Some minor documentation improvements are listed in "Bug Fixes" below.
 
 ** Bug Fixes
 
+#52981: find: the '-delete' action no longer complains about disappeared files
+        when the '-ignore_readdir_race' option is given, too.  That action will
+        also returns true in such a case now.
+
 #52220: 'find -D' without any further argument no longer crashes.
         Bug present since the implementation of -D in FINDUTILS_4_3_1-1.
 
diff --git a/doc/find.texi b/doc/find.texi
index 3580be75..0089193e 100644
--- a/doc/find.texi
+++ b/doc/find.texi
@@ -1424,7 +1424,15 @@ gives a significant increase in search speed.
 If a file disappears after its name has been read from a directory but
 before @code{find} gets around to examining the file with @code{stat},
 don't issue an error message.  If you don't specify this option, an
-error message will be issued.  This option can be useful in system
+error message will be issued.
+
+Furthermore, @code{find} with the @samp{-ignore_readdir_race} option
+will ignore errors of the @samp{-delete} action in the case the file
+has disappeared since the parent directory was read: it will not output
+an error diagnostic, and the return code of the @samp{-delete} action
+will be true.
+
+This option can be useful in system
 scripts (cron scripts, for example) that examine areas of the
 filesystem that change frequently (mail queues, temporary directories,
 and so forth), because this scenario is common for those sorts of
@@ -2787,6 +2795,11 @@ explicitly.
 
 If @samp{-delete} fails, @code{find}'s exit status will be nonzero
 (when it eventually exits).
+
+Together with the @samp{-ignore_readdir_race} option, @code{find} will
+ignore errors of the @samp{-delete} action in the case the file has disappeared
+since the parent directory was read: it will not output an error diagnostic, and
+the return code of the @samp{-delete} action will be true.
 @end deffn
 
 @node Adding Tests
diff --git a/find/find.1 b/find/find.1
index e376ab6c..6aef4a2e 100644
--- a/find/find.1
+++ b/find/find.1
@@ -483,6 +483,17 @@ one part of the filesystem with this option on and part of it with this option
 off (if you need to do that, you will need to issue two \fBfind\fR commands
 instead, one with the option and one without it).
 
+Furthermore,
+.B find
+with the
+.B \-ignore_readdir_race
+option will ignore errors of the
+.B \-delete
+action in the case the file has disappeared since the parent directory was read:
+it will not output an error diagnostic, and the return code of the
+.B \-delete
+action will be true.
+
 .IP "\-maxdepth \fIlevels\fR"
 Descend at most \fIlevels\fR (a non-negative integer) levels of
 directories below the starting-points.
@@ -1043,6 +1054,17 @@ and
 .B \-delete
 together.
 
+Together with the
+.B \-ignore_readdir_race
+option,
+.B find
+will ignore errors of the
+.B \-delete
+action in the case the file has disappeared since the parent directory was
+read: it will not output an error diagnostic, and the return code of the
+.B \-delete
+action will be true.
+
 .IP "\-exec \fIcommand\fR ;"
 Execute \fIcommand\fR; true if 0 status is returned.  All following
 arguments to
diff --git a/find/pred.c b/find/pred.c
index 7e2a7bde..af3bacbc 100644
--- a/find/pred.c
+++ b/find/pred.c
@@ -316,6 +316,12 @@ pred_delete (const char *pathname, struct stat *stat_buf, struct predicate *pred
 	}
       else
 	{
+	  if (ENOENT == errno && options.ignore_readdir_race)
+	    {
+	      /* Ignore unlink() error for vanished files.  */
+	      errno = 0;
+	      return true;
+	    }
 	  if (EISDIR == errno)
 	    {
 	      if ((flags & AT_REMOVEDIR) == 0)
-- 
2.16.1

