From: Kazuya Mio <k-mio@sx.jp.nec.com>
Date: Thu, 18 Nov 2010 21:51:25 +0000 (+0000)
Subject: e4defrag: fix segfault when e4defrag races with unlink/truncate
X-Git-Tag: v1.42-WIP-0702~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b07f014face2e2aa0abf8a3266fd716152cd0cd4;p=thirdparty%2Fe2fsprogs.git

e4defrag: fix segfault when e4defrag races with unlink/truncate

If a file gets deleted or truncated while e4defrag is trying to
operate on it, it's possible for it seg fault.

Addresses-Red-Hat-Bugzilla: #641926

Reported-by: Michal Piotrowski <mkkp4x4@gmail.com>
Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

diff --git a/misc/e4defrag.c b/misc/e4defrag.c
index e795987c1..9008bc27f 100644
--- a/misc/e4defrag.c
+++ b/misc/e4defrag.c
@@ -942,7 +942,7 @@ static int get_file_extents(int fd, struct fiemap_extent_list **ext_list_head)
 		fiemap_buf->fm_start = pos;
 		memset(ext_buf, 0, ext_buf_size);
 		ret = ioctl(fd, FS_IOC_FIEMAP, fiemap_buf);
-		if (ret < 0)
+		if (ret < 0 || fiemap_buf->fm_mapped_extents == 0)
 			goto out;
 		for (i = 0; i < fiemap_buf->fm_mapped_extents; i++) {
 			ext_list = NULL;