[PATCH 0/5] Optimisations for state management

[PATCH 0/5] Optimisations for state management

[Trond Myklebust]

The following patches constitute a grab bag of minor optimisations when
the NFS client is managing its state.

Trond Myklebust (5):
  NFSv4: Don't check file access when reclaiming state
  NFSv4: Don't ask for the change attribute when reclaiming state
  NFSv4: Don't request a GETATTR on open_downgrade.
  NFSv4: Don't request close-to-open attribute when holding a delegation
  NFSv4: Optimise away forced revalidation when we know the attributes
    are OK

 fs/nfs/delegation.c |  4 ----
 fs/nfs/inode.c      |  2 +-
 fs/nfs/nfs4proc.c   | 23 +++++++++++++++++------
 fs/nfs/nfs4xdr.c    |  7 ++-----
 4 files changed, 20 insertions(+), 16 deletions(-)

-- 
2.7.4

[PATCH 1/5] NFSv4: Don't check file access when reclaiming state

[Trond Myklebust]

If we're reclaiming state after a reboot, or as part of returning a
delegation, we don't need to check access modes again.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/nfs4proc.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 6a1d650e0419..4eead738da8e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1221,6 +1221,7 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	atomic_inc(&sp->so_count);
 	p->o_arg.open_flags = flags;
 	p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
+	p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
 	p->o_arg.share_access = nfs4_map_atomic_open_share(server,
 			fmode, flags);
 	/* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
@@ -1228,8 +1229,14 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	if (!(flags & O_EXCL)) {
 		/* ask server to check for all possible rights as results
 		 * are cached */
-		p->o_arg.access = NFS4_ACCESS_READ | NFS4_ACCESS_MODIFY |
-				  NFS4_ACCESS_EXTEND | NFS4_ACCESS_EXECUTE;
+		switch (p->o_arg.claim) {
+		case NFS4_OPEN_CLAIM_NULL:
+		case NFS4_OPEN_CLAIM_FH:
+			p->o_arg.access = NFS4_ACCESS_READ |
+				NFS4_ACCESS_MODIFY |
+				NFS4_ACCESS_EXTEND |
+				NFS4_ACCESS_EXECUTE;
+		}
 	}
 	p->o_arg.clientid = server->nfs_client->cl_clientid;
 	p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
@@ -1239,7 +1246,6 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	p->o_arg.bitmask = nfs4_bitmask(server, label);
 	p->o_arg.open_bitmap = &nfs4_fattr_bitmap[0];
 	p->o_arg.label = nfs4_label_copy(p->a_label, label);
-	p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
 	switch (p->o_arg.claim) {
 	case NFS4_OPEN_CLAIM_NULL:
 	case NFS4_OPEN_CLAIM_DELEGATE_CUR:
-- 
2.7.4

[PATCH 2/5] NFSv4: Don't ask for the change attribute when reclaiming state

[Trond Myklebust]

We don't need to ask for the change attribute when returning a delegation
or recovering from a server reboot, and it could actually cause us to
obtain an incorrect value if we're using a pNFS flavour that requires
LAYOUTCOMMIT.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/nfs4proc.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 4eead738da8e..1e7e0754a96d 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -226,7 +226,6 @@ static const u32 nfs4_pnfs_open_bitmap[3] = {
 
 static const u32 nfs4_open_noattr_bitmap[3] = {
 	FATTR4_WORD0_TYPE
-	| FATTR4_WORD0_CHANGE
 	| FATTR4_WORD0_FILEID,
 };
 
-- 
2.7.4

[PATCH 3/5] NFSv4: Don't request a GETATTR on open_downgrade.

[Trond Myklebust]

If we're not closing the file completely, there is no need to request
close-to-open attributes.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/nfs4xdr.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index fc89e5ed07ee..43cc989b5c06 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -2328,7 +2328,6 @@ static void nfs4_xdr_enc_open_downgrade(struct rpc_rqst *req,
 	encode_sequence(xdr, &args->seq_args, &hdr);
 	encode_putfh(xdr, args->fh, &hdr);
 	encode_open_downgrade(xdr, args, &hdr);
-	encode_getfattr(xdr, args->bitmask, &hdr);
 	encode_nops(&hdr);
 }
 
@@ -6115,9 +6114,6 @@ static int nfs4_xdr_dec_open_downgrade(struct rpc_rqst *rqstp,
 	if (status)
 		goto out;
 	status = decode_open_downgrade(xdr, res);
-	if (status != 0)
-		goto out;
-	decode_getfattr(xdr, res->fattr, res->server);
 out:
 	return status;
 }
-- 
2.7.4

[PATCH 4/5] NFSv4: Don't request close-to-open attribute when holding a delegation

[Trond Myklebust]

If holding a delegation, we do not need to ask the server to return
close-to-open cache consistency attributes as part of the CLOSE
compound.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/nfs4proc.c | 10 ++++++++--
 fs/nfs/nfs4xdr.c  |  3 ++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 1e7e0754a96d..ded8854bc32f 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3141,8 +3141,15 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
 		goto out_wait;
 	}
 
-	if (calldata->arg.fmode == 0)
+	if (calldata->arg.fmode == 0) {
 		task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];
+
+		/* Close-to-open cache consistency revalidation */
+		if (!nfs4_have_delegation(inode, FMODE_READ))
+			calldata->arg.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
+		else
+			calldata->arg.bitmask = NULL;
+	}
 	if (calldata->roc)
 		pnfs_roc_get_barrier(inode, &calldata->roc_barrier);
 
@@ -3225,7 +3232,6 @@ int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait)
 	if (IS_ERR(calldata->arg.seqid))
 		goto out_free_calldata;
 	calldata->arg.fmode = 0;
-	calldata->arg.bitmask = server->cache_consistency_bitmask;
 	calldata->res.fattr = &calldata->fattr;
 	calldata->res.seqid = calldata->arg.seqid;
 	calldata->res.server = server;
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 43cc989b5c06..a8bebb52df78 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -2250,7 +2250,8 @@ static void nfs4_xdr_enc_close(struct rpc_rqst *req, struct xdr_stream *xdr,
 	encode_sequence(xdr, &args->seq_args, &hdr);
 	encode_putfh(xdr, args->fh, &hdr);
 	encode_close(xdr, args, &hdr);
-	encode_getfattr(xdr, args->bitmask, &hdr);
+	if (args->bitmask != NULL)
+		encode_getfattr(xdr, args->bitmask, &hdr);
 	encode_nops(&hdr);
 }
 
-- 
2.7.4

[PATCH 5/5] NFSv4: Optimise away forced revalidation when we know the attributes are OK

[Trond Myklebust]

The NFS_INO_REVAL_FORCED flag needs to be set if we just got a delegation,
and we see that there might still be some ambiguity as to whether or not
our attribute or data cache are valid.
In practice, this means that a call to nfs_check_inode_attributes() will
have noticed a discrepancy between cached attributes and measured ones,
so let's move the setting of NFS_INO_REVAL_FORCED to there.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/delegation.c | 4 ----
 fs/nfs/inode.c      | 2 +-
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index dff600ae0d74..d7df5e67b0c1 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -391,10 +391,6 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
 	rcu_assign_pointer(nfsi->delegation, delegation);
 	delegation = NULL;
 
-	/* Ensure we revalidate the attributes and page cache! */
-	spin_lock(&inode->i_lock);
-	nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
-	spin_unlock(&inode->i_lock);
 	trace_nfs4_set_delegation(inode, res->delegation_type);
 
 out:
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index bf4ec5ecc97e..3575e3408bd7 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1317,7 +1317,7 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat
 		invalid |= NFS_INO_INVALID_ATIME;
 
 	if (invalid != 0)
-		nfs_set_cache_invalid(inode, invalid);
+		nfs_set_cache_invalid(inode, invalid | NFS_INO_REVAL_FORCED);
 
 	nfsi->read_cache_jiffies = fattr->time_start;
 	return 0;
-- 
2.7.4

Re: [PATCH 1/5] NFSv4: Don't check file access when reclaiming state

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2528 bytes --]

Hi Trond,

[auto build test WARNING on nfs/linux-next]
[also build test WARNING on v4.9-rc4 next-20161110]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Trond-Myklebust/Optimisations-for-state-management/20161111-054856
base:   git://git.linux-nfs.org/projects/trondmy/linux-nfs.git linux-next
config: x86_64-eywa-module (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   fs/nfs/nfs4proc.c: In function 'nfs4_opendata_alloc':
>> fs/nfs/nfs4proc.c:1232:3: warning: enumeration value 'NFS4_OPEN_CLAIM_PREVIOUS' not handled in switch [-Wswitch]
      switch (p->o_arg.claim) {
      ^~~~~~
>> fs/nfs/nfs4proc.c:1232:3: warning: enumeration value 'NFS4_OPEN_CLAIM_DELEGATE_CUR' not handled in switch [-Wswitch]
>> fs/nfs/nfs4proc.c:1232:3: warning: enumeration value 'NFS4_OPEN_CLAIM_DELEGATE_PREV' not handled in switch [-Wswitch]
>> fs/nfs/nfs4proc.c:1232:3: warning: enumeration value 'NFS4_OPEN_CLAIM_DELEG_CUR_FH' not handled in switch [-Wswitch]
>> fs/nfs/nfs4proc.c:1232:3: warning: enumeration value 'NFS4_OPEN_CLAIM_DELEG_PREV_FH' not handled in switch [-Wswitch]

vim +/NFS4_OPEN_CLAIM_PREVIOUS +1232 fs/nfs/nfs4proc.c

  1216			goto err_free_label;
  1217		nfs_sb_active(dentry->d_sb);
  1218		p->dentry = dget(dentry);
  1219		p->dir = parent;
  1220		p->owner = sp;
  1221		atomic_inc(&sp->so_count);
  1222		p->o_arg.open_flags = flags;
  1223		p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
  1224		p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
  1225		p->o_arg.share_access = nfs4_map_atomic_open_share(server,
  1226				fmode, flags);
  1227		/* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
  1228		 * will return permission denied for all bits until close */
  1229		if (!(flags & O_EXCL)) {
  1230			/* ask server to check for all possible rights as results
  1231			 * are cached */
> 1232			switch (p->o_arg.claim) {
  1233			case NFS4_OPEN_CLAIM_NULL:
  1234			case NFS4_OPEN_CLAIM_FH:
  1235				p->o_arg.access = NFS4_ACCESS_READ |
  1236					NFS4_ACCESS_MODIFY |
  1237					NFS4_ACCESS_EXTEND |
  1238					NFS4_ACCESS_EXECUTE;
  1239			}
  1240		}

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 25516 bytes --]

Re: [PATCH 1/5] NFSv4: Don't check file access when reclaiming state

[Anna Schumaker]

Hi Trond,

On 11/10/2016 04:41 PM, Trond Myklebust wrote:
> If we're reclaiming state after a reboot, or as part of returning a
> delegation, we don't need to check access modes again.
> 
> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
> ---
>  fs/nfs/nfs4proc.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 6a1d650e0419..4eead738da8e 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -1221,6 +1221,7 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
>  	atomic_inc(&sp->so_count);
>  	p->o_arg.open_flags = flags;
>  	p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
> +	p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
>  	p->o_arg.share_access = nfs4_map_atomic_open_share(server,
>  			fmode, flags);
>  	/* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
> @@ -1228,8 +1229,14 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
>  	if (!(flags & O_EXCL)) {
>  		/* ask server to check for all possible rights as results
>  		 * are cached */
> -		p->o_arg.access = NFS4_ACCESS_READ | NFS4_ACCESS_MODIFY |
> -				  NFS4_ACCESS_EXTEND | NFS4_ACCESS_EXECUTE;
> +		switch (p->o_arg.claim) {
> +		case NFS4_OPEN_CLAIM_NULL:
> +		case NFS4_OPEN_CLAIM_FH:
> +			p->o_arg.access = NFS4_ACCESS_READ |
> +				NFS4_ACCESS_MODIFY |
> +				NFS4_ACCESS_EXTEND |
> +				NFS4_ACCESS_EXECUTE;
> +		}

This adds these warnings when I compile:

fs/nfs/nfs4proc.c: In function 'nfs4_opendata_alloc':
fs/nfs/nfs4proc.c:1232:3: error: enumeration value 'NFS4_OPEN_CLAIM_PREVIOUS' not handled in switch [-Werror=switch]
   switch (p->o_arg.claim) {
   ^~~~~~
fs/nfs/nfs4proc.c:1232:3: error: enumeration value 'NFS4_OPEN_CLAIM_DELEGATE_CUR' not handled in switch [-Werror=switch]
fs/nfs/nfs4proc.c:1232:3: error: enumeration value 'NFS4_OPEN_CLAIM_DELEGATE_PREV' not handled in switch [-Werror=switch]
fs/nfs/nfs4proc.c:1232:3: error: enumeration value 'NFS4_OPEN_CLAIM_DELEG_CUR_FH' not handled in switch [-Werror=switch]
fs/nfs/nfs4proc.c:1232:3: error: enumeration value 'NFS4_OPEN_CLAIM_DELEG_PREV_FH' not handled in switch [-Werror=switch]

Thanks,
Anna


>  	}
>  	p->o_arg.clientid = server->nfs_client->cl_clientid;
>  	p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
> @@ -1239,7 +1246,6 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
>  	p->o_arg.bitmask = nfs4_bitmask(server, label);
>  	p->o_arg.open_bitmap = &nfs4_fattr_bitmap[0];
>  	p->o_arg.label = nfs4_label_copy(p->a_label, label);
> -	p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
>  	switch (p->o_arg.claim) {
>  	case NFS4_OPEN_CLAIM_NULL:
>  	case NFS4_OPEN_CLAIM_DELEGATE_CUR:
> 

[PATCH 1/5] NFSv4: Don't check file access when reclaiming state

[Trond Myklebust]

If we're reclaiming state after a reboot, or as part of returning a
delegation, we don't need to check access modes again.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/nfs4proc.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 241da19b7da4..b582df89c083 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1221,6 +1221,7 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	atomic_inc(&sp->so_count);
 	p->o_arg.open_flags = flags;
 	p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
+	p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
 	p->o_arg.share_access = nfs4_map_atomic_open_share(server,
 			fmode, flags);
 	/* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
@@ -1228,8 +1229,16 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	if (!(flags & O_EXCL)) {
 		/* ask server to check for all possible rights as results
 		 * are cached */
-		p->o_arg.access = NFS4_ACCESS_READ | NFS4_ACCESS_MODIFY |
-				  NFS4_ACCESS_EXTEND | NFS4_ACCESS_EXECUTE;
+		switch (p->o_arg.claim) {
+		default:
+			break;
+		case NFS4_OPEN_CLAIM_NULL:
+		case NFS4_OPEN_CLAIM_FH:
+			p->o_arg.access = NFS4_ACCESS_READ |
+				NFS4_ACCESS_MODIFY |
+				NFS4_ACCESS_EXTEND |
+				NFS4_ACCESS_EXECUTE;
+		}
 	}
 	p->o_arg.clientid = server->nfs_client->cl_clientid;
 	p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
@@ -1239,7 +1248,6 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
 	p->o_arg.bitmask = nfs4_bitmask(server, label);
 	p->o_arg.open_bitmap = &nfs4_fattr_bitmap[0];
 	p->o_arg.label = nfs4_label_copy(p->a_label, label);
-	p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
 	switch (p->o_arg.claim) {
 	case NFS4_OPEN_CLAIM_NULL:
 	case NFS4_OPEN_CLAIM_DELEGATE_CUR:
-- 
2.9.3