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.
--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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