[PATCH] NFSD: Clear cached acl after setting a zero-length default posix acl:

[Kinglong Mee <kinglongmee@gmail.com>]

After setting ACL for directory, I got two problems that caused
by the cached zero-length default posix acl.

This patch just clears the cached zero-length default posix acl
after setting.

First problem:
# nfs4_setfacl -s A::OWNER@:RWX /mnt/123/; touch /mnt/123/test
............ hang ...........

Second problem:
# nfs4_setfacl -s A::OWNER@:RWX /mnt/123/; nfs4_getfacl /mnt/123/
[ 1610.167668] ------------[ cut here ]------------
[ 1610.168320] kernel BUG at /root/nfs/linux/fs/nfsd/nfs4acl.c:239!
[ 1610.168320] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 1610.168320] Modules linked in: nfsv4(OE) nfs(OE) nfsd(OE) 
rpcsec_gss_krb5 fscache ip6t_rpfilter ip6t_REJECT cfg80211 xt_conntrack 
rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables 
ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 
ip6table_mangle ip6table_security ip6table_raw ip6table_filter 
ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 
nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw 
auth_rpcgss nfs_acl snd_intel8x0 ppdev lockd snd_ac97_codec ac97_bus 
snd_pcm snd_timer e1000 pcspkr parport_pc snd parport serio_raw joydev 
i2c_piix4 sunrpc(OE) microcode soundcore i2c_core ata_generic pata_acpi 
[last unloaded: nfsd]
[ 1610.168320] CPU: 0 PID: 27397 Comm: nfsd Tainted: G           OE 
3.15.0-rc1+ #15
[ 1610.168320] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS 
VirtualBox 12/01/2006
[ 1610.168320] task: ffff88005ab653d0 ti: ffff88005a944000 task.ti: 
ffff88005a944000
[ 1610.168320] RIP: 0010:[<ffffffffa034d5ed>]  [<ffffffffa034d5ed>] 
_posix_to_nfsv4_one+0x3cd/0x3d0 [nfsd]
[ 1610.168320] RSP: 0018:ffff88005a945b00  EFLAGS: 00010293
[ 1610.168320] RAX: 0000000000000001 RBX: ffff88006700bac0 RCX: 
0000000000000000
[ 1610.168320] RDX: 0000000000000000 RSI: ffff880067c83f00 RDI: 
ffff880068233300
[ 1610.168320] RBP: ffff88005a945b48 R08: ffffffff81c64830 R09: 
0000000000000000
[ 1610.168320] R10: ffff88004ea85be0 R11: 000000000000f475 R12: 
ffff880068233300
[ 1610.168320] R13: 0000000000000003 R14: 0000000000000002 R15: 
ffff880068233300
[ 1610.168320] FS:  0000000000000000(0000) GS:ffff880077800000(0000) 
knlGS:0000000000000000
[ 1610.168320] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1610.168320] CR2: 00007f5bcbd3b0b9 CR3: 0000000001c0f000 CR4: 
00000000000006f0
[ 1610.168320] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
0000000000000000
[ 1610.168320] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 
0000000000000400
[ 1610.168320] Stack:
[ 1610.168320]  ffffffff00000000 0000000b67c83500 000000076700bac0 
0000000000000000
[ 1610.168320]  ffff88006700bac0 ffff880068233300 ffff88005a945c08 
0000000000000002
[ 1610.168320]  0000000000000000 ffff88005a945b88 ffffffffa034e2d5 
000000065a945b68
[ 1610.168320] Call Trace:
[ 1610.168320]  [<ffffffffa034e2d5>] nfsd4_get_nfs4_acl+0x95/0x150 [nfsd]
[ 1610.168320]  [<ffffffffa03400d6>] nfsd4_encode_fattr+0x646/0x1e70 [nfsd]
[ 1610.168320]  [<ffffffff816a6e6e>] ? kmemleak_alloc+0x4e/0xb0
[ 1610.168320]  [<ffffffffa0327962>] ? 
nfsd_setuser_and_check_port+0x52/0x80 [nfsd]
[ 1610.168320]  [<ffffffff812cd4bb>] ? selinux_cred_prepare+0x1b/0x30
[ 1610.168320]  [<ffffffffa0341caa>] nfsd4_encode_getattr+0x5a/0x60 [nfsd]
[ 1610.168320]  [<ffffffffa0341e07>] nfsd4_encode_operation+0x67/0x110 
[nfsd]
[ 1610.168320]  [<ffffffffa033844d>] nfsd4_proc_compound+0x21d/0x810 [nfsd]
[ 1610.168320]  [<ffffffffa0324d9b>] nfsd_dispatch+0xbb/0x200 [nfsd]
[ 1610.168320]  [<ffffffffa00850cd>] svc_process_common+0x46d/0x6d0 [sunrpc]
[ 1610.168320]  [<ffffffffa0085433>] svc_process+0x103/0x170 [sunrpc]
[ 1610.168320]  [<ffffffffa032472f>] nfsd+0xbf/0x130 [nfsd]
[ 1610.168320]  [<ffffffffa0324670>] ? nfsd_destroy+0x80/0x80 [nfsd]
[ 1610.168320]  [<ffffffff810a5202>] kthread+0xd2/0xf0
[ 1610.168320]  [<ffffffff810a5130>] ? insert_kthread_work+0x40/0x40
[ 1610.168320]  [<ffffffff816c1ebc>] ret_from_fork+0x7c/0xb0
[ 1610.168320]  [<ffffffff810a5130>] ? insert_kthread_work+0x40/0x40
[ 1610.168320] Code: 78 02 e9 e7 fc ff ff 31 c0 31 d2 31 c9 66 89 45 ce 
41 8b 04 24 66 89 55 d0 66 89 4d d2 48 8d 04 80 49 8d 5c 84 04 e9 37 fd 
ff ff <0f> 0b 90 0f 1f 44 00 00 55 8b 56 08 c7 07 00 00 00 00 8b 46 0c
[ 1610.168320] RIP  [<ffffffffa034d5ed>] _posix_to_nfsv4_one+0x3cd/0x3d0 
[nfsd]
[ 1610.168320]  RSP <ffff88005a945b00>
[ 1610.257313] ---[ end trace 838254e3e352285b ]---

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
---
  fs/nfsd/nfs4acl.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
index de5d66b..4eb0a9f 100644
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -834,6 +834,8 @@ nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct 
svc_fh *fhp,
  	if (S_ISDIR(inode->i_mode)) {
  		host_error = inode->i_op->set_acl(inode, dpacl,
  						  ACL_TYPE_DEFAULT);
+		if (!dpacl->a_count)
+			forget_cached_acl(inode, ACL_TYPE_DEFAULT);
  	}

  out_release:
-- 
1.9.0