On Fri, Nov 8, 2013 at 5:07 AM, Andreas Schneider <asn@xxxxxxxxxxxxxx> wrote: > Hello, > > I did run the Samba testsuite and have a failing test > (samba.vfstest.stream_depot). It revealed that it only fails on btrfs. The > reason is that a simple check fails: > > if (smb_fname_base->st.st_ex_nlink == 2) > > If you create a directory on btrfs and check stat: > > $ mkdir x > $ stat x > File: ‘x’ > Size: 0 Blocks: 0 IO Block: 4096 directory > Device: 2bh/43d Inode: 3834720 Links: 1 > Access: (0755/drwxr-xr-x) Uid: ( 1000/ asn) Gid: ( 100/ users) > Access: 2013-11-08 11:54:32.431040963 +0100 > Modify: 2013-11-08 11:54:32.430040956 +0100 > Change: 2013-11-08 11:54:32.430040956 +0100 > Birth: - > > then you see Links: 1. On ext4 or other filesystems: > > mkdir x > stat x > File: ‘x’ > Size: 4096 Blocks: 8 IO Block: 4096 directory > Device: fd00h/64768d Inode: 8126886 Links: 2 > Access: (0755/drwxr-xr-x) Uid: ( 1000/ asn) Gid: ( 100/ users) > Access: 2013-11-08 11:54:55.428212340 +0100 > Modify: 2013-11-08 11:54:55.427212319 +0100 > Change: 2013-11-08 11:54:55.427212319 +0100 > Birth: - > > the link count for a directory differs: Links: 2. > > Why is btrfs different here? Could someone explain this? As I understand it, inferring the number of directory entries from st_nlink is an optimization that isn't universally valid. If that count is 1, it must be considered invalid, and programs that don't handle this correctly are broken. Coreutils handle this, at least... -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
