Re: [PATCH 3/3] nfsd: Drop BUG_ON and don't reply SECLABEL when exports migrated

["J. Bruce Fields" <bfields@fieldses.org>]

Thanks, applying for 4.2 and stable.--b.

On Tue, Jul 07, 2015 at 10:16:37AM +0800, Kinglong Mee wrote:
> When setting refer for exports entry, 
> 
> [   88.414272] kernel BUG at fs/nfsd/nfs4xdr.c:2249!
> [   88.414828] invalid opcode: 0000 [#1] SMP
> [   88.415368] Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache nfsd xfs libcrc32c iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi iosf_mbi ppdev btrfs coretemp crct10dif_pclmul crc32_pclmul crc32c_intel xor ghash_clmulni_intel raid6_pq vmw_balloon parport_pc parport i2c_piix4 shpchp vmw_vmci acpi_cpufreq auth_rpcgss nfs_acl lockd grace sunrpc vmwgfx drm_kms_helper ttm drm mptspi mptscsih serio_raw mptbase e1000 scsi_transport_spi ata_generic pata_acpi [last unloaded: nfsd]
> [   88.417827] CPU: 0 PID: 2116 Comm: nfsd Not tainted 4.0.7-300.fc22.x86_64 #1
> [   88.418448] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/20/2014
> [   88.419093] task: ffff880079146d50 ti: ffff8800785d8000 task.ti: ffff8800785d8000
> [   88.419729] RIP: 0010:[<ffffffffa04b3c10>]  [<ffffffffa04b3c10>] nfsd4_encode_fattr+0x820/0x1f00 [nfsd]
> [   88.420376] RSP: 0000:ffff8800785db998  EFLAGS: 00010206
> [   88.421027] RAX: 0000000000000001 RBX: 000000000018091a RCX: ffff88006668b980
> [   88.421676] RDX: 00000000fffef7fc RSI: 0000000000000000 RDI: ffff880078d05000
> [   88.422315] RBP: ffff8800785dbb58 R08: ffff880078d043f8 R09: ffff880078d4a000
> [   88.422968] R10: 0000000000010000 R11: 0000000000000002 R12: 0000000000b0a23a
> [   88.423612] R13: ffff880078d05000 R14: ffff880078683100 R15: ffff88006668b980
> [   88.424295] FS:  0000000000000000(0000) GS:ffff88007c600000(0000) knlGS:0000000000000000
> [   88.424944] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   88.425597] CR2: 00007f40bc370f90 CR3: 0000000035af5000 CR4: 00000000001407f0
> [   88.426285] Stack:
> [   88.426921]  ffff8800785dbaa8 ffffffffa049e4af ffff8800785dba08 ffffffff813298f0
> [   88.427585]  ffff880078683300 ffff8800769b0de8 0000089d00000001 0000000087f805e0
> [   88.428228]  ffff880000000000 ffff880079434a00 0000000000000000 ffff88006668b980
> [   88.428877] Call Trace:
> [   88.429527]  [<ffffffffa049e4af>] ? exp_get_by_name+0x7f/0xb0 [nfsd]
> [   88.430168]  [<ffffffff813298f0>] ? inode_doinit_with_dentry+0x210/0x6a0
> [   88.430807]  [<ffffffff8123833e>] ? d_lookup+0x2e/0x60
> [   88.431449]  [<ffffffff81236133>] ? dput+0x33/0x230
> [   88.432097]  [<ffffffff8123f214>] ? mntput+0x24/0x40
> [   88.432719]  [<ffffffff812272b2>] ? path_put+0x22/0x30
> [   88.433340]  [<ffffffffa049ac87>] ? nfsd_cross_mnt+0xb7/0x1c0 [nfsd]
> [   88.433954]  [<ffffffffa04b54e0>] nfsd4_encode_dirent+0x1b0/0x3d0 [nfsd]
> [   88.434601]  [<ffffffffa04b5330>] ? nfsd4_encode_getattr+0x40/0x40 [nfsd]
> [   88.435172]  [<ffffffffa049c991>] nfsd_readdir+0x1c1/0x2a0 [nfsd]
> [   88.435710]  [<ffffffffa049a530>] ? nfsd_direct_splice_actor+0x20/0x20 [nfsd]
> [   88.436447]  [<ffffffffa04abf30>] nfsd4_encode_readdir+0x120/0x220 [nfsd]
> [   88.437011]  [<ffffffffa04b58cd>] nfsd4_encode_operation+0x7d/0x190 [nfsd]
> [   88.437566]  [<ffffffffa04aa6dd>] nfsd4_proc_compound+0x24d/0x6f0 [nfsd]
> [   88.438157]  [<ffffffffa0496103>] nfsd_dispatch+0xc3/0x220 [nfsd]
> [   88.438680]  [<ffffffffa006f0cb>] svc_process_common+0x43b/0x690 [sunrpc]
> [   88.439192]  [<ffffffffa0070493>] svc_process+0x103/0x1b0 [sunrpc]
> [   88.439694]  [<ffffffffa0495a57>] nfsd+0x117/0x190 [nfsd]
> [   88.440194]  [<ffffffffa0495940>] ? nfsd_destroy+0x90/0x90 [nfsd]
> [   88.440697]  [<ffffffff810bb728>] kthread+0xd8/0xf0
> [   88.441260]  [<ffffffff810bb650>] ? kthread_worker_fn+0x180/0x180
> [   88.441762]  [<ffffffff81789e58>] ret_from_fork+0x58/0x90
> [   88.442322]  [<ffffffff810bb650>] ? kthread_worker_fn+0x180/0x180
> [   88.442879] Code: 0f 84 93 05 00 00 83 f8 ea c7 85 a0 fe ff ff 00 00 27 30 0f 84 ba fe ff ff 85 c0 0f 85 a5 fe ff ff e9 e3 f9 ff ff 0f 1f 44 00 00 <0f> 0b 66 0f 1f 44 00 00 be 04 00 00 00 4c 89 ef 4c 89 8d 68 fe
> [   88.444052] RIP  [<ffffffffa04b3c10>] nfsd4_encode_fattr+0x820/0x1f00 [nfsd]
> [   88.444658]  RSP <ffff8800785db998>
> [   88.445232] ---[ end trace 6cb9d0487d94a29f ]---
> 
> Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
> ---
>  fs/nfsd/nfs4xdr.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 5463385..75e0563 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -2143,6 +2143,7 @@ nfsd4_encode_aclname(struct xdr_stream *xdr, struct svc_rqst *rqstp,
>  #define WORD0_ABSENT_FS_ATTRS (FATTR4_WORD0_FS_LOCATIONS | FATTR4_WORD0_FSID | \
>  			      FATTR4_WORD0_RDATTR_ERROR)
>  #define WORD1_ABSENT_FS_ATTRS FATTR4_WORD1_MOUNTED_ON_FILEID
> +#define WORD2_ABSENT_FS_ATTRS 0
>  
>  #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
>  static inline __be32
> @@ -2171,7 +2172,7 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
>  { return 0; }
>  #endif
>  
> -static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *rdattr_err)
> +static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *bmval2, u32 *rdattr_err)
>  {
>  	/* As per referral draft:  */
>  	if (*bmval0 & ~WORD0_ABSENT_FS_ATTRS ||
> @@ -2184,6 +2185,7 @@ static __be32 fattr_handle_absent_fs(u32 *bmval0, u32 *bmval1, u32 *rdattr_err)
>  	}
>  	*bmval0 &= WORD0_ABSENT_FS_ATTRS;
>  	*bmval1 &= WORD1_ABSENT_FS_ATTRS;
> +	*bmval2 &= WORD2_ABSENT_FS_ATTRS;
>  	return 0;
>  }
>  
> @@ -2246,8 +2248,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
>  	BUG_ON(bmval2 & ~nfsd_suppattrs2(minorversion));
>  
>  	if (exp->ex_fslocs.migrated) {
> -		BUG_ON(bmval[2]);
> -		status = fattr_handle_absent_fs(&bmval0, &bmval1, &rdattr_err);
> +		status = fattr_handle_absent_fs(&bmval0, &bmval1, &bmval2, &rdattr_err);
>  		if (status)
>  			goto out;
>  	}
> @@ -2286,8 +2287,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
>  	}
>  
>  #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
> -	if ((bmval[2] & FATTR4_WORD2_SECURITY_LABEL) ||
> -			bmval[0] & FATTR4_WORD0_SUPPORTED_ATTRS) {
> +	if ((bmval2 & FATTR4_WORD2_SECURITY_LABEL) ||
> +	     bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
>  		err = security_inode_getsecctx(d_inode(dentry),
>  						&context, &contextlen);
>  		contextsupport = (err == 0);
> -- 
> 2.4.3