On Mon 28 Oct 2013 05:51:26 PM EDT, J. Bruce Fields wrote:
> On Mon, Oct 28, 2013 at 10:57:26AM -0400, Anna Schumaker wrote:
>> This patch adds in the SEEK operation used by clients doing an llseek on
>> a file to find either hole or data sections in a file. I'm faking the
>> "allocated" status right now, since I haven't quite figured out how to
>> tell if a range is allocated on disk yet.
>>
>> This patch is missing correctly determining the "allocated" status of
>> the HOLE / DATA range. I expect I'll need to learn all about how fiemap
>> works before properly setting these values.
>>
>> Signed-off-by: Anna Schumaker <bjschuma@xxxxxxxxxx>
>> ---
>> fs/nfsd/nfs4proc.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>> fs/nfsd/nfs4xdr.c | 40 ++++++++++++++++++++++++++++++++++++++--
>> fs/nfsd/xdr4.h | 15 +++++++++++++++
>> include/linux/nfs4.h | 2 +-
>> 4 files changed, 98 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>> index 3210c6f..bc45ed2 100644
>> --- a/fs/nfsd/nfs4proc.c
>> +++ b/fs/nfsd/nfs4proc.c
>> @@ -1064,6 +1064,45 @@ nfsd4_write_plus(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> return nfserr_union_notsupp;
>> }
>>
>> +static __be32
>> +nfsd4_seek(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> + struct nfsd4_seek *seek)
>> +{
>> + struct file *file;
>> + loff_t pos, end_pos;
>> + __be32 status;
>> +
>> + status = nfs4_preprocess_stateid_op(SVC_NET(rqstp), cstate,
>> + &seek->seek_stateid,
>> + RD_STATE | WR_STATE, &file);
>
> Note nfs4_preprocess_stateid_op requires the caller to hold the state
> lock. Andyou want to either hold it till you're done using "file" or
> take a reference on file before dropping it.
That's useful to know. I'll fix it up here, and anywhere else I call
nfs4_preprocess_stateid_op()!
>
> --b.
>
>> + if (status != nfs_ok)
>> + return status;
>> +
>> + if (seek->seek_whence == NFS4_CONTENT_DATA) {
>> + pos = vfs_llseek(file, seek->seek_offset, SEEK_DATA);
>> + end_pos = vfs_llseek(file, pos, SEEK_HOLE);
>> + seek->seek_allocated = true;
>> + } else {
>> + pos = vfs_llseek(file, seek->seek_offset, SEEK_HOLE);
>> + end_pos = vfs_llseek(file, pos, SEEK_DATA);
>> + seek->seek_allocated = false;
>> + }
>> +
>> + if (pos < 0)
>> + return nfserrno(pos);
>> + else if (end_pos == -ENXIO) {
>> + seek->seek_length = 0;
>> + seek->seek_eof = true;
>> + } else if (end_pos < 0)
>> + return nfserrno(end_pos);
>> + else
>> + seek->seek_length = end_pos - pos;
>> +
>> + seek->seek_offset = pos;
>> +
>> + return nfs_ok;
>> +}
>> +
>> /* This routine never returns NFS_OK! If there are no other errors, it
>> * will return NFSERR_SAME or NFSERR_NOT_SAME depending on whether the
>> * attributes matched. VERIFY is implemented by mapping NFSERR_SAME
>> @@ -1885,6 +1924,11 @@ static struct nfsd4_operation nfsd4_ops[] = {
>> .op_rsize_bop = (nfsd4op_rsize)nfsd4_write_rsize,
>> .op_get_currentstateid = (stateid_getter)nfsd4_get_writestateid,
>> },
>> +
>> + [OP_SEEK] = {
>> + .op_func = (nfsd4op_func)nfsd4_seek,
>> + .op_name = "OP_SEEK",
>> + },
>> };
>>
>> #ifdef NFSD_DEBUG
>> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
>> index 1e4e9af..8434740 100644
>> --- a/fs/nfsd/nfs4xdr.c
>> +++ b/fs/nfsd/nfs4xdr.c
>> @@ -1511,6 +1511,22 @@ nfsd4_decode_write_plus(struct nfsd4_compoundargs *argp,
>> }
>>
>> static __be32
>> +nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
>> +{
>> + DECODE_HEAD;
>> +
>> + status = nfsd4_decode_stateid(argp, &seek->seek_stateid);
>> + if (status)
>> + return status;
>> +
>> + READ_BUF(12);
>> + READ64(seek->seek_offset);
>> + READ32(seek->seek_whence);
>> +
>> + DECODE_TAIL;
>> +}
>> +
>> +static __be32
>> nfsd4_decode_noop(struct nfsd4_compoundargs *argp, void *p)
>> {
>> return nfs_ok;
>> @@ -1693,7 +1709,7 @@ static nfsd4_dec nfsd42_dec_ops[] = {
>> [OP_OFFLOAD_STATUS] = (nfsd4_dec)nfsd4_decode_notsupp,
>> [OP_WRITE_PLUS] = (nfsd4_dec)nfsd4_decode_write_plus,
>> [OP_READ_PLUS] = (nfsd4_dec)nfsd4_decode_notsupp,
>> - [OP_SEEK] = (nfsd4_dec)nfsd4_decode_notsupp,
>> + [OP_SEEK] = (nfsd4_dec)nfsd4_decode_seek,
>> [OP_IO_ADVISE] = (nfsd4_dec)nfsd4_decode_notsupp,
>> };
>>
>> @@ -3650,6 +3666,26 @@ nfsd4_encode_write_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
>> }
>>
>> static __be32
>> +nfsd4_encode_seek(struct nfsd4_compoundres *resp, __be32 nfserr,
>> + struct nfsd4_seek *seek)
>> +{
>> + __be32 *p;
>> +
>> + if (nfserr)
>> + return nfserr;
>> +
>> + RESERVE_SPACE(28);
>> + WRITE32(seek->seek_eof);
>> + WRITE32(seek->seek_whence);
>> + WRITE64(seek->seek_offset);
>> + WRITE64(seek->seek_length);
>> + WRITE32(seek->seek_allocated);
>> + ADJUST_ARGS();
>> +
>> + return nfserr;
>> +}
>> +
>> +static __be32
>> nfsd4_encode_noop(struct nfsd4_compoundres *resp, __be32 nfserr, void *p)
>> {
>> return nfserr;
>> @@ -3730,7 +3766,7 @@ static nfsd4_enc nfsd4_enc_ops[] = {
>> [OP_OFFLOAD_STATUS] = (nfsd4_enc)nfsd4_encode_noop,
>> [OP_WRITE_PLUS] = (nfsd4_enc)nfsd4_encode_write_plus,
>> [OP_READ_PLUS] = (nfsd4_enc)nfsd4_encode_noop,
>> - [OP_SEEK] = (nfsd4_enc)nfsd4_encode_noop,
>> + [OP_SEEK] = (nfsd4_enc)nfsd4_encode_seek,
>> [OP_IO_ADVISE] = (nfsd4_enc)nfsd4_encode_noop,
>> };
>>
>> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
>> index aaef9ab..ae9debc 100644
>> --- a/fs/nfsd/xdr4.h
>> +++ b/fs/nfsd/xdr4.h
>> @@ -451,6 +451,20 @@ struct nfsd4_write_plus {
>> struct nfsd42_write_res wp_res;
>> };
>>
>> +struct nfsd4_seek {
>> + /* request */
>> + stateid_t seek_stateid;
>> +
>> + /* Shared between request and response */
>> + u64 seek_offset;
>> + u32 seek_whence;
>> +
>> + /* response */
>> + u32 seek_eof;
>> + u64 seek_length;
>> + u32 seek_allocated;
>> +};
>> +
>> struct nfsd4_op {
>> int opnum;
>> __be32 status;
>> @@ -499,6 +513,7 @@ struct nfsd4_op {
>>
>> /* NFSv4.2 */
>> struct nfsd4_write_plus write_plus;
>> + struct nfsd4_seek seek;
>> } u;
>> struct nfs4_replay * replay;
>> };
>> diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
>> index 55ed991..81d6b09 100644
>> --- a/include/linux/nfs4.h
>> +++ b/include/linux/nfs4.h
>> @@ -128,7 +128,7 @@ enum nfs_opnum4 {
>> Needs to be updated if more operations are defined in future.*/
>>
>> #define FIRST_NFS4_OP OP_ACCESS
>> -#define LAST_NFS4_OP OP_WRITE_PLUS
>> +#define LAST_NFS4_OP OP_SEEK
>>
>> enum nfsstat4 {
>> NFS4_OK = 0,
>> --
>> 1.8.4.1
>>
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