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From 921c30674e9bc719e7c2747deb6deb04be2adb4b Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <>
Date: Thu, 9 Nov 2017 11:35:22 -0600
Subject: [PATCH] db: increase metadump's default overly long extent discard 

Back in 88b8e1d6d7 ("Make xfs_metadump more robust against bad data"),
metadump grew the ability to ignore a directory extent if it was longer
than 20 blocks.  Presumably this was to protect metadump from dumping
absurdly long extents resulting from bmbt corruption, but it's certainly
possible to create a directory with an extent longer than 20 blocks.
Hilariously, the discards happen with no warning unless the caller
explicitly set -w.

This was raised to 1000 blocks in 7431d134fe8 ("Increase default maximum
extent size for xfs_metadump when copying..."), but it's still possible
to create a directory with an extent longer than 1000 blocks.

Increase the threshold to MAXEXTLEN blocks because it's totally valid
for the filesystem to create extents up to that length.

Signed-off-by: Darrick J. Wong <>
Reviewed-by: Carlos Maiolino <>
Signed-off-by: Eric Sandeen <>
 db/metadump.c           | 2 +-
 man/man8/xfs_metadump.8 | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Index: xfsprogs-4.5.0/db/metadump.c
--- xfsprogs-4.5.0.orig/db/metadump.c
+++ xfsprogs-4.5.0/db/metadump.c
@@ -32,7 +32,7 @@
 #include "field.h"
 #include "dir2.h"
-#define DEFAULT_MAX_EXT_SIZE	1000
  * It's possible that multiple files in a directory (or attributes
Index: xfsprogs-4.5.0/man/man8/xfs_metadump.8
--- xfsprogs-4.5.0.orig/man/man8/xfs_metadump.8
+++ xfsprogs-4.5.0/man/man8/xfs_metadump.8
@@ -114,7 +114,7 @@ copied.
 .B \-m
 Set the maximum size of an allowed metadata extent.  Extremely large metadata
 extents are likely to be corrupt, and will be skipped if they exceed
-this value.  The default size is 1000 blocks.
+this value.  The default size is 2097151 blocks.
 .B \-o
 Disables obfuscation of file names and extended attributes.