filesystems: Add a paragraph about post-EOF reclaim after crash.

diff --git a/Filesystems.m4 b/Filesystems.m4
index 9035de5218f1ab8da1e4c6e399438f2b523002a8..e2ac56198451a3f2bee58d0bbc764399aa86958d 100644 (file)
--- a/Filesystems.m4
+++ b/Filesystems.m4
@@ -955,6 +955,11 @@ file fragmentation, but they can cause confusion because they are
 accounted identically to other blocks, making files appear to use
 more data blocks than expected. </p>
 
+<p> If the system crashes while preallocated post-EOF blocks exist,
+the space will be recovered the next time the affected file gets closed
+(after it has been opened of course) by the normal reclaim mechanism
+which happens when a file is being closed. </p>
+
 SUBSECTION(«Reverse Mapping»)
 
 <p> This feature was implemented in 2018. It adds yet another B-tree to