Re: [PATCH 2/2] NFS: Cleanup decode_attr_fs_locations function.

[Dean Hildebrand <seattleplus@gmail.com>]

J. Bruce Fields wrote:
> On Fri, Oct 17, 2008 at 11:17:48AM -0700, Dean Hildebrand wrote:
>   
>> a) Reduce nesting level of loops.
>> b) Use correct data types.
>> c) Use nloc and nserv instead of n and m variable names.
>> d) Try to clean up formatting of debugging statements.
>> e) Move while loops to for loops.
>>     
>
> Does this also fix a possible infinite loop in the inner loop?
>   
Doh, I put that fix in this patch instead of the first.  I will move it 
to the first. and apply your comments from
the other email.
Dean
>     1
>> Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com>
>> ---
>>  fs/nfs/nfs4xdr.c |   71 +++++++++++++++++++++++++++++-------------------------
>>  1 files changed, 38 insertions(+), 33 deletions(-)
>>
>> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
>> index 5e59481..0e78fbd 100644
>> --- a/fs/nfs/nfs4xdr.c
>> +++ b/fs/nfs/nfs4xdr.c
>> @@ -2560,7 +2560,8 @@ out_eio:
>>  
>>  static int decode_attr_fs_locations(struct xdr_stream *xdr, uint32_t *bitmap, struct nfs4_fs_locations *res)
>>  {
>> -	int n;
>> +	u32 nloc;
>> +	unsigned int i;
>>  	__be32 *p;
>>  	int status = -EIO;
>>  
>> @@ -2574,53 +2575,57 @@ static int decode_attr_fs_locations(struct xdr_stream *xdr, uint32_t *bitmap, st
>>  	if (unlikely(status != 0))
>>  		goto out;
>>  	READ_BUF(4);
>> -	READ32(n);
>> -	if (n <= 0)
>> +	READ32(nloc);
>> +	if (nloc <= 0)
>>  		goto out_eio;
>> -
>> -	if (n > NFS4_FS_LOCATIONS_MAXENTRIES) {
>> -		dprintk("%s: using first %u of %d fs locations\n",
>> -			__func__, NFS4_FS_LOCATIONS_MAXENTRIES, n);
>> -		n = NFS4_FS_LOCATIONS_MAXENTRIES;
>> +	if (nloc > NFS4_FS_LOCATIONS_MAXENTRIES) {
>> +		dprintk("%s: using first %u of %u fs locations\n",
>> +			__func__, NFS4_FS_LOCATIONS_MAXENTRIES, nloc);
>> +		nloc = NFS4_FS_LOCATIONS_MAXENTRIES;
>>  	} else {
>> -		dprintk("%s: using %d fs locations\n",
>> -			__func__, n);
>> +		dprintk("%s: using %u fs locations\n",
>> +			__func__, nloc);
>>  	}
>>  
>>  	res->nlocations = 0;
>> -	while (res->nlocations < n) {
>> -		u32 m;
>> -		struct nfs4_fs_location *loc = &res->locations[res->nlocations];
>> +	for (i = 0; i < nloc; i++) {
>> +		u32 nserv;
>> +		unsigned int totalserv, j;
>> +		struct nfs4_fs_location *loc = &res->locations[i];
>>  
>>  		READ_BUF(4);
>> -		READ32(m);
>> +		READ32(nserv);
>> +
>> +		totalserv = nserv;
>> +		if (nserv >  NFS4_FS_LOCATION_MAXSERVERS) {
>> +			dprintk("%s: Using first %u of %u servers "
>> +				"returned for location %u\n",
>> +				__func__, NFS4_FS_LOCATION_MAXSERVERS,
>> +				nserv, i);
>> +			nserv = NFS4_FS_LOCATION_MAXSERVERS;
>> +		}
>>  
>>  		loc->nservers = 0;
>> -		dprintk("%s: servers ", __func__);
>> -		while (loc->nservers < m) {
>> +		dprintk("%s: Servers ", __func__);
>> +		for (j = 0; j < nserv; j++) {
>>  			struct nfs4_string *server = &loc->servers[loc->nservers];
>>  			status = decode_opaque_inline(xdr, &server->len, &server->data);
>>  			if (unlikely(status != 0))
>>  				goto out_eio;
>>  			dprintk("%s ", server->data);
>> -			if (loc->nservers < NFS4_FS_LOCATION_MAXSERVERS)
>> -				loc->nservers++;
>> -			else {
>> -				unsigned int i;
>> -				dprintk("%s: using first %u of %u servers "
>> -					"returned for location %u\n",
>> -						__func__,
>> -						NFS4_FS_LOCATION_MAXSERVERS,
>> -						m, res->nlocations);
>> -				for (i = loc->nservers; i < m; i++) {
>> -					unsigned int len;
>> -					char *data;
>> -					status = decode_opaque_inline(xdr, &len, &data);
>> -					if (unlikely(status != 0))
>> -						goto out_eio;
>> -				}
>> -			}
>> +			loc->nservers++;
>> +		}
>> +		dprintk("\n");
>> +
>> +		/* Decode and ignore overflow servers */
>> +		for (j = loc->nservers; j < totalserv; j++) {
>> +			unsigned int len;
>> +			char *data;
>> +			status = decode_opaque_inline(xdr, &len, &data);
>> +			if (unlikely(status != 0))
>> +				goto out_eio;
>>  		}
>> +
>>  		status = decode_pathname(xdr, &loc->rootpath);
>>  		if (unlikely(status != 0))
>>  			goto out_eio;
>> -- 
>> 1.5.3.3
>>
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