From: Chengyu Song <csong84@gatech.edu>
Date: Tue, 24 Mar 2015 22:12:56 +0000 (-0400)
Subject: btrfs: incorrect handling for fiemap_fill_next_extent return
X-Git-Tag: v3.12.45~96
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9cb9cfc9f2a6f6c3177744b50f5514190f0cca96;p=thirdparty%2Fkernel%2Fstable.git

btrfs: incorrect handling for fiemap_fill_next_extent return

commit 26e726afe01c1c82072cf23a5ed89ce25f39d9f2 upstream.

fiemap_fill_next_extent returns 0 on success, -errno on error, 1 if this was
the last extent that will fit in user array. If 1 is returned, the return
value may eventually returned to user space, which should not happen, according
to manpage of ioctl.

Signed-off-by: Chengyu Song <csong84@gatech.edu>
Reviewed-by: David Sterba <dsterba@suse.cz>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 7015d9079bd10..855f6668cb8e8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4228,8 +4228,11 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 		}
 		ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
 					      em_len, flags);
-		if (ret)
+		if (ret) {
+			if (ret == 1)
+				ret = 0;
 			goto out_free;
+		}
 	}
 out_free:
 	free_extent_map(em);