Re: [PATCH 2/2] NFSD: Added TEST_STATEID opreation

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

On Fri, May 06, 2011 at 02:57:35PM -0400, bjschuma@netapp.com wrote:
> From: Bryan Schumaker <bjschuma@netapp.com>
> 
> This operation is used by the client to check the validity of a list of
> stateids.
> 
> Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
> ---
>  fs/nfsd/nfs4proc.c  |    5 ++
>  fs/nfsd/nfs4state.c |   66 ++++++++++++++++++++++++++
>  fs/nfsd/nfs4xdr.c   |  128 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>  fs/nfsd/xdr4.h      |   21 ++++++++
>  4 files changed, 218 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 7e00116..a856f30 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1412,6 +1412,11 @@ static struct nfsd4_operation nfsd4_ops[] = {
>  		.op_flags = OP_HANDLES_WRONGSEC,
>  		.op_name = "OP_SECINFO_NO_NAME",
>  	},
> +	[OP_TEST_STATEID] = {
> +		.op_func = (nfsd4op_func)nfsd4_test_stateid,
> +		.op_flags = ALLOWED_WITHOUT_FH,
> +		.op_name = "OP_TEST_STATEID",
> +	},
>  	[OP_FREE_STATEID] = {
>  		.op_func = (nfsd4op_func)nfsd4_free_stateid,
>  		.op_flags = ALLOWED_WITHOUT_FH,
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 6beec13..c7bb3ce 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -37,6 +37,7 @@
>  #include <linux/slab.h>
>  #include <linux/namei.h>
>  #include <linux/swap.h>
> +#include <linux/pagemap.h>
>  #include <linux/sunrpc/svcauth_gss.h>
>  #include <linux/sunrpc/clnt.h>
>  #include "xdr4.h"
> @@ -3140,6 +3141,35 @@ static int is_delegation_stateid(stateid_t *stateid)
>  	return stateid->si_fileid == 0;
>  }
>  
> +static __be32 nfs4_validate_stateid(stateid_t *stateid, int flags, struct file **filpp, struct svc_fh *current_fh)
> +{
> +	struct nfs4_stateid *stp = NULL;
> +	__be32 status = nfserr_stale_stateid;
> +
> +	if (STALE_STATEID(stateid))
> +		goto out;
> +
> +	status = nfserr_expired;
> +	stp = search_for_stateid(stateid);
> +	if (!stp)
> +		goto out;
> +	status = nfserr_bad_stateid;
> +
> +	if (!stp->st_stateowner->so_confirmed)
> +		goto out;
> +
> +	status = check_stateid_generation(stateid, &stp->st_stateid, flags);
> +	if (status)
> +		goto out;
> +
> +	status = nfs4_check_openmode(stp, flags);

It doesn't make sense to be doing openmode checks here, since
test_stateid doesn't check whether a stateid could be used for read or
write.  (And OPENMODE isn't a legal return value for test_stateid.)

> +	if (status)
> +		goto out;
> +	status = nfs_ok;
> +out:
> +	return status;
> +}
> +
>  /*
>  * Checks for stateid operations
>  */
> @@ -3220,6 +3250,42 @@ out:
>  }
>  
>  /*
> + * Test if the stateid is valid
> + */
> +__be32
> +nfsd4_test_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> +		   struct nfsd4_test_stateid *test_stateid)
> +{
> +	stateid_t *stateid = NULL;
> +	int *resp = NULL;
> +	struct svc_fh *current_fh;
> +	unsigned int cur_id_page = 0;
> +	unsigned int cur_resp_page = 0;
> +	int i;
> +	unsigned int lock_flags = LOCK_STATE | RD_STATE | WR_STATE;
> +	unsigned int open_flags = OPEN_STATE | RD_STATE | WR_STATE;
> +
> +	current_fh = &cstate->current_fh;
> +
> +	for (i = 0; i < test_stateid->ts_num_ids; i++) {
> +		if ((i % test_stateid->ts_stateids->items_per_page) == 0) {
> +			stateid = (stateid_t *)test_stateid->ts_stateids->items[cur_id_page].first_item;
> +			cur_id_page++;
> +		}
> +		if ((i % test_stateid->ts_valid->items_per_page) == 0) {
> +			resp = (int *)test_stateid->ts_valid->items[cur_resp_page].first_item;
> +			cur_resp_page++;
> +		}
> +		*resp = nfs4_validate_stateid(stateid, lock_flags, NULL, current_fh);
> +		if (!*resp)
> +			*resp = nfs4_validate_stateid(stateid, open_flags, NULL, current_fh);
> +		stateid++;
> +		resp++;
> +	}
> +	return nfs_ok;
> +}
> +
> +/*
>   * Free a state id
>   */
>  __be32
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 5da6874..c92c4d2 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -44,6 +44,7 @@
>  #include <linux/namei.h>
>  #include <linux/statfs.h>
>  #include <linux/utsname.h>
> +#include <linux/pagemap.h>
>  #include <linux/sunrpc/svcauth_gss.h>
>  
>  #include "idmap.h"
> @@ -1274,6 +1275,98 @@ nfsd4_decode_sequence(struct nfsd4_compoundargs *argp,
>  	DECODE_TAIL;
>  }
>  
> +static void
> +nfsd4_free_ts_pagearray(struct nfsd4_ts_pagearray *array)
> +{
> +	unsigned int i;
> +	struct page *page;
> +	for (i = 0; i < array->num_pages; i++) {
> +		kunmap(array->items[i].page);
> +		put_page(array->items[i].page);
> +	}
> +	page = array->page_ptr;
> +	put_page(page);
> +}
> +
> +static struct nfsd4_ts_pagearray *
> +nfsd4_alloc_ts_pagearray(struct nfsd4_test_stateid *test_stateid, unsigned int item_size)
> +{
> +	unsigned int num_pages;
> +	struct nfsd4_ts_pagearray *array;
> +	struct page *page;
> +	int i = 0;
> +
> +	page = alloc_page(GFP_KERNEL);
> +	if (page == NULL)
> +		goto out_nomem;
> +
> +	array = kmap(page);
> +	array->num_pages = 0;
> +	array->items_per_page = PAGE_SIZE / item_size;
> +	array->page_ptr  = page;
> +
> +	num_pages = ((test_stateid->ts_num_ids * item_size) / PAGE_SIZE) + 1;
> +
> +	for (i = 0; i < num_pages; i++) {
> +		page = alloc_page(GFP_KERNEL);
> +		if (page == NULL)
> +			goto out_freepages;
> +		array->items[i].page = page;
> +		array->items[i].first_item = kmap(page);
> +		array->num_pages += 1;
> +	}
> +	return array;
> +
> +out_freepages:
> +	nfsd4_free_ts_pagearray(array);
> +out_nomem:
> +	return ERR_PTR(-ENOMEM);
> +}
> +
> +static __be32
> +nfsd4_decode_test_stateid(struct nfsd4_compoundargs *argp, struct nfsd4_test_stateid *test_stateid)
> +{
> +	stateid_t * si = NULL;
> +	unsigned int cur_page = 0;
> +	struct page *page;
> +	int i;
> +
> +	DECODE_HEAD;
> +	READ_BUF(4);
> +	READ32(test_stateid->ts_num_ids);

Surely we need some sort of sanity-check on the size of that thing?
Otherwise the num_pages calculation above can overflow and weird stuff
happens.

> +
> +	test_stateid->ts_stateids = nfsd4_alloc_ts_pagearray(test_stateid, sizeof(stateid_t));
> +	if (IS_ERR(test_stateid->ts_stateids))
> +		return PTR_ERR(test_stateid->ts_stateids);
> +
> +	test_stateid->ts_valid = nfsd4_alloc_ts_pagearray(test_stateid, sizeof(int));

Will this be freed in every case?  I guess you're assuming the encode
function will be called whenever the decode succeeds.  Off the top of my
head, I don't think that's true if xdr decoding of a later op fails.

--b.

> +	if (IS_ERR(test_stateid->ts_valid)) {
> +		status = PTR_ERR(test_stateid->ts_valid);
> +		goto out_free_pages;
> +	}
> +
> +	/* Read in a list of stateids provided by the client */
> +	for (i = 0; i < test_stateid->ts_num_ids; i++) {
> +		if ((i % test_stateid->ts_stateids->items_per_page) == 0) {
> +			si = test_stateid->ts_stateids->items[cur_page].first_item;
> +			cur_page++;
> +		}
> +		nfsd4_decode_stateid(argp, si);
> +		si++;
> +	}
> +	kunmap(page);
> +	status = 0;
> +out:
> +	return status;
> +xdr_error:
> +	dprintk("NFSD: xdr error (%s:%d)\n", __FILE__, __LINE__);
> +	status = nfserr_bad_xdr;
> +	nfsd4_free_ts_pagearray(test_stateid->ts_valid);
> +out_free_pages:
> +	nfsd4_free_ts_pagearray(test_stateid->ts_stateids);
> +	goto out;
> +}
> +
>  static __be32 nfsd4_decode_reclaim_complete(struct nfsd4_compoundargs *argp, struct nfsd4_reclaim_complete *rc)
>  {
>  	DECODE_HEAD;
> @@ -1393,7 +1486,7 @@ static nfsd4_dec nfsd41_dec_ops[] = {
>  	[OP_SECINFO_NO_NAME]	= (nfsd4_dec)nfsd4_decode_secinfo_no_name,
>  	[OP_SEQUENCE]		= (nfsd4_dec)nfsd4_decode_sequence,
>  	[OP_SET_SSV]		= (nfsd4_dec)nfsd4_decode_notsupp,
> -	[OP_TEST_STATEID]	= (nfsd4_dec)nfsd4_decode_notsupp,
> +	[OP_TEST_STATEID]	= (nfsd4_dec)nfsd4_decode_test_stateid,
>  	[OP_WANT_DELEGATION]	= (nfsd4_dec)nfsd4_decode_notsupp,
>  	[OP_DESTROY_CLIENTID]	= (nfsd4_dec)nfsd4_decode_notsupp,
>  	[OP_RECLAIM_COMPLETE]	= (nfsd4_dec)nfsd4_decode_reclaim_complete,
> @@ -3166,6 +3259,37 @@ nfsd4_encode_sequence(struct nfsd4_compoundres *resp, int nfserr,
>  	return 0;
>  }
>  
> +__be32
> +nfsd4_encode_test_stateid(struct nfsd4_compoundres *resp, int nfserr,
> +			  struct nfsd4_test_stateid *test_stateid)
> +{
> +	__be32 *p;
> +	unsigned int i;
> +	unsigned int cur_page = 0;
> +	int *valid = NULL;
> +
> +	if (!nfserr) {
> +		RESERVE_SPACE(4);
> +		WRITE32(test_stateid->ts_num_ids);
> +		ADJUST_ARGS();
> +
> +		for (i = 0; i < test_stateid->ts_num_ids; i++) {
> +			if ((i % test_stateid->ts_valid->items_per_page) == 0) {
> +				valid = (int *)test_stateid->ts_valid->items[cur_page].first_item;
> +				cur_page++;
> +			}
> +			RESERVE_SPACE(4);
> +			WRITE32(*valid);
> +			ADJUST_ARGS();
> +			valid++;
> +		}
> +	}
> +
> +	nfsd4_free_ts_pagearray(test_stateid->ts_valid);
> +	nfsd4_free_ts_pagearray(test_stateid->ts_stateids);
> +	return nfserr;
> +}
> +
>  static __be32
>  nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *p)
>  {
> @@ -3234,7 +3358,7 @@ static nfsd4_enc nfsd4_enc_ops[] = {
>  	[OP_SECINFO_NO_NAME]	= (nfsd4_enc)nfsd4_encode_secinfo_no_name,
>  	[OP_SEQUENCE]		= (nfsd4_enc)nfsd4_encode_sequence,
>  	[OP_SET_SSV]		= (nfsd4_enc)nfsd4_encode_noop,
> -	[OP_TEST_STATEID]	= (nfsd4_enc)nfsd4_encode_noop,
> +	[OP_TEST_STATEID]	= (nfsd4_enc)nfsd4_encode_test_stateid,
>  	[OP_WANT_DELEGATION]	= (nfsd4_enc)nfsd4_encode_noop,
>  	[OP_DESTROY_CLIENTID]	= (nfsd4_enc)nfsd4_encode_noop,
>  	[OP_RECLAIM_COMPLETE]	= (nfsd4_enc)nfsd4_encode_noop,
> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
> index ed1784d..0455f55 100644
> --- a/fs/nfsd/xdr4.h
> +++ b/fs/nfsd/xdr4.h
> @@ -342,6 +342,24 @@ struct nfsd4_setclientid_confirm {
>  	nfs4_verifier	sc_confirm;
>  };
>  
> +struct nfsd4_ts_pagearray_item {
> +	struct page *page;
> +	void *first_item;
> +};
> +
> +struct nfsd4_ts_pagearray {
> +	unsigned int num_pages;
> +	unsigned int items_per_page;
> +	struct page *page_ptr;
> +	struct nfsd4_ts_pagearray_item items[0];
> +};
> +
> +struct nfsd4_test_stateid {
> +	__be32		ts_num_ids;             /* request */
> +	struct nfsd4_ts_pagearray *ts_stateids; /* request */
> +	struct nfsd4_ts_pagearray *ts_valid;    /* response */
> +};
> +
>  struct nfsd4_free_stateid {
>  	stateid_t	fr_stateid;         /* request */
>  	__be32		fr_status;          /* response */
> @@ -437,6 +455,7 @@ struct nfsd4_op {
>  		struct nfsd4_destroy_session	destroy_session;
>  		struct nfsd4_sequence		sequence;
>  		struct nfsd4_reclaim_complete	reclaim_complete;
> +		struct nfsd4_test_stateid	test_stateid;
>  		struct nfsd4_free_stateid	free_stateid;
>  	} u;
>  	struct nfs4_replay *			replay;
> @@ -570,6 +589,8 @@ extern __be32 nfsd4_delegreturn(struct svc_rqst *rqstp,
>  		struct nfsd4_compound_state *, struct nfsd4_delegreturn *dr);
>  extern __be32 nfsd4_renew(struct svc_rqst *rqstp,
>  			  struct nfsd4_compound_state *, clientid_t *clid);
> +extern __be32 nfsd4_test_stateid(struct svc_rqst *rqstp,
> +		struct nfsd4_compound_state *, struct nfsd4_test_stateid *test_stateid);
>  extern __be32 nfsd4_free_stateid(struct svc_rqst *rqstp,
>  		struct nfsd4_compound_state *, struct nfsd4_free_stateid *free_stateid);
>  #endif
> -- 
> 1.7.5.1
>