> On Mar 27, 2018, at 10:53 AM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>
> NFSv4 read compound processing invokes nfsd_splice_read and
> nfs_readv directly, so the trace points currently in nfsd_read are
> not effective for NFSv4 reads.
>
> Move and copy the trace points so that NFSv4 reads are captured.
> Also, we want to record any local I/O error that occurs, and
> the total count of bytes that were actually moved. And, also
> whether splice or vectored read was used.
>
> The svc_fh is not passed to the read helpers, so some code
> duplication is necessary.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> fs/nfsd/nfs4proc.c | 5 +++++
> fs/nfsd/nfs4xdr.c | 56 +++++++++++++++++++++++++++++++++++++---------------
> fs/nfsd/trace.h | 4 +++-
> fs/nfsd/vfs.c | 54 ++++++++++++++++++++++----------------------------
> fs/nfsd/vfs.h | 8 ++++---
> 5 files changed, 76 insertions(+), 51 deletions(-)
>
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index b93673e..39016b6 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -751,6 +751,9 @@ static __be32 nfsd4_do_lookupp(struct svc_rqst *rqstp, struct svc_fh *fh)
> if (read->rd_offset >= OFFSET_MAX)
> return nfserr_inval;
>
> + trace_nfsd_read_start(rqstp, &cstate->current_fh,
> + read->rd_offset, read->rd_length);
> +
> /*
> * If we do a zero copy read, then a client will see read data
> * that reflects the state of the file *after* performing the
> @@ -783,6 +786,8 @@ static __be32 nfsd4_do_lookupp(struct svc_rqst *rqstp, struct svc_fh *fh)
> {
> if (u->read.rd_filp)
> fput(u->read.rd_filp);
> + trace_nfsd_read_done(u->read.rd_rqstp, u->read.rd_fhp,
> + u->read.rd_offset, u->read.rd_length);
> }
>
> static __be32
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index e502fd1..d03059a 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -37,6 +37,7 @@
> #include <linux/file.h>
> #include <linux/slab.h>
> #include <linux/namei.h>
> +#include <linux/fsnotify.h>
> #include <linux/statfs.h>
> #include <linux/utsname.h>
> #include <linux/pagemap.h>
> @@ -50,6 +51,7 @@
> #include "cache.h"
> #include "netns.h"
> #include "pnfs.h"
> +#include "trace.h"
>
> #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
> #include <linux/security.h>
> @@ -3416,28 +3418,28 @@ static __be32 nfsd4_encode_splice_read(
> {
> struct xdr_stream *xdr = &resp->xdr;
> struct xdr_buf *buf = xdr->buf;
> + int host_err;
> u32 eof;
> long len;
> int space_left;
> - __be32 nfserr;
> __be32 *p = xdr->p - 2;
>
> /* Make sure there will be room for padding if needed */
> if (xdr->end - xdr->p < 1)
> return nfserr_resource;
>
> + trace_nfsd_read_splice(resp->rqstp, read->rd_fhp,
> + read->rd_offset, maxcount);
> len = maxcount;
> - nfserr = nfsd_splice_read(read->rd_rqstp, file,
> + host_err = nfsd_splice_read(read->rd_rqstp, file,
> read->rd_offset, &maxcount);
> - if (nfserr) {
> - /*
> - * nfsd_splice_actor may have already messed with the
> - * page length; reset it so as not to confuse
> - * xdr_truncate_encode:
> - */
> - buf->page_len = 0;
> - return nfserr;
> - }
> + if (host_err < 0)
> + goto err;
> + trace_nfsd_read_io_done(read->rd_rqstp, read->rd_fhp,
> + read->rd_offset, maxcount);
> + maxcount = host_err;
> + nfsdstats.io_read += maxcount;
> + fsnotify_access(file);
>
> eof = nfsd_eof_on_read(len, maxcount, read->rd_offset,
> d_inode(read->rd_fhp->fh_dentry)->i_size);
> @@ -3470,6 +3472,17 @@ static __be32 nfsd4_encode_splice_read(
> xdr->end = (__be32 *)((void *)xdr->end + space_left);
>
> return 0;
> +
> +err:
> + /*
> + * nfsd_splice_actor may have already messed with the
> + * page length; reset it so as not to confuse
> + * xdr_truncate_encode:
> + */
> + buf->page_len = 0;
> + trace_nfsd_read_err(read->rd_rqstp, read->rd_fhp,
> + read->rd_offset, host_err);
> + return nfserrno(host_err);
> }
>
> static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
> @@ -3477,12 +3490,12 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
> struct file *file, unsigned long maxcount)
> {
> struct xdr_stream *xdr = &resp->xdr;
> + int host_err;
> u32 eof;
> int v;
> int starting_len = xdr->buf->len - 8;
> long len;
> int thislen;
> - __be32 nfserr;
> __be32 tmp;
> __be32 *p;
> u32 zzz = 0;
> @@ -3510,11 +3523,18 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
> }
> read->rd_vlen = v;
>
> + trace_nfsd_read_vector(resp->rqstp, read->rd_fhp,
> + read->rd_offset, maxcount);
> len = maxcount;
> - nfserr = nfsd_readv(file, read->rd_offset, resp->rqstp->rq_vec,
> - read->rd_vlen, &maxcount);
> - if (nfserr)
> - return nfserr;
> + host_err = nfsd_readv(file, read->rd_offset, resp->rqstp->rq_vec,
> + read->rd_vlen, &maxcount);
> + if (host_err < 0)
> + goto err;
> + trace_nfsd_read_io_done(resp->rqstp, read->rd_fhp,
> + read->rd_offset, maxcount);
I missed a spot.
+ maxcount = host_err;
> + nfsdstats.io_read += maxcount;
> + fsnotify_access(file);
> +
> xdr_truncate_encode(xdr, starting_len + 8 + ((maxcount+3)&~3));
>
> eof = nfsd_eof_on_read(len, maxcount, read->rd_offset,
> @@ -3530,6 +3550,10 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
> &zzz, pad);
> return 0;
>
> +err:
> + trace_nfsd_read_err(resp->rqstp, read->rd_fhp,
> + read->rd_offset, host_err);
> + return nfserrno(host_err);
> }
>
> static __be32
> diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
> index 653e9ee..a8bbd9d 100644
> --- a/fs/nfsd/trace.h
> +++ b/fs/nfsd/trace.h
> @@ -43,7 +43,8 @@
> TP_ARGS(rqstp, fhp, offset, len))
>
> DEFINE_NFSD_IO_EVENT(read_start);
> -DEFINE_NFSD_IO_EVENT(read_opened);
> +DEFINE_NFSD_IO_EVENT(read_splice);
> +DEFINE_NFSD_IO_EVENT(read_vector);
> DEFINE_NFSD_IO_EVENT(read_io_done);
> DEFINE_NFSD_IO_EVENT(read_done);
> DEFINE_NFSD_IO_EVENT(write_start);
> @@ -82,6 +83,7 @@
> int len), \
> TP_ARGS(rqstp, fhp, offset, len))
>
> +DEFINE_NFSD_ERR_EVENT(read_err);
> DEFINE_NFSD_ERR_EVENT(write_err);
>
> #include "state.h"
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index ee59a0b..0fa54b5 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -881,19 +881,7 @@ static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe,
> return __splice_from_pipe(pipe, sd, nfsd_splice_actor);
> }
>
> -static __be32
> -nfsd_finish_read(struct file *file, unsigned long *count, int host_err)
> -{
> - if (host_err >= 0) {
> - nfsdstats.io_read += host_err;
> - *count = host_err;
> - fsnotify_access(file);
> - return 0;
> - } else
> - return nfserrno(host_err);
> -}
> -
> -__be32 nfsd_splice_read(struct svc_rqst *rqstp,
> +int nfsd_splice_read(struct svc_rqst *rqstp,
> struct file *file, loff_t offset, unsigned long *count)
> {
> struct splice_desc sd = {
> @@ -902,23 +890,18 @@ __be32 nfsd_splice_read(struct svc_rqst *rqstp,
> .pos = offset,
> .u.data = rqstp,
> };
> - int host_err;
>
> rqstp->rq_next_page = rqstp->rq_respages + 1;
> - host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
> - return nfsd_finish_read(file, count, host_err);
> + return splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor);
> }
>
> -__be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
> - unsigned long *count)
> +int nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
> + unsigned long *count)
> {
> struct iov_iter iter;
> - int host_err;
>
> iov_iter_kvec(&iter, READ | ITER_KVEC, vec, vlen, *count);
> - host_err = vfs_iter_read(file, &iter, &offset, 0);
> -
> - return nfsd_finish_read(file, count, host_err);
> + return vfs_iter_read(file, &iter, &offset, 0);
> }
>
> /*
> @@ -1025,6 +1008,7 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
> {
> struct file *file;
> struct raparms *ra;
> + int host_err;
> __be32 err;
>
> trace_nfsd_read_start(rqstp, fhp, offset, *count);
> @@ -1034,14 +1018,24 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
>
> ra = nfsd_init_raparms(file);
>
> - trace_nfsd_read_opened(rqstp, fhp, offset, *count);
> -
> - if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
> - err = nfsd_splice_read(rqstp, file, offset, count);
> - else
> - err = nfsd_readv(file, offset, vec, vlen, count);
> -
> - trace_nfsd_read_io_done(rqstp, fhp, offset, *count);
> + if (file->f_op->splice_read &&
> + test_bit(RQ_SPLICE_OK, &rqstp->rq_flags)) {
> + trace_nfsd_read_splice(rqstp, fhp, offset, *count);
> + host_err = nfsd_splice_read(rqstp, file, offset, count);
> + } else {
> + trace_nfsd_read_vector(rqstp, fhp, offset, *count);
> + host_err = nfsd_readv(file, offset, vec, vlen, count);
> + }
> + if (host_err >= 0) {
> + trace_nfsd_read_io_done(rqstp, fhp, offset, host_err);
> + nfsdstats.io_read += host_err;
> + *count = host_err;
> + fsnotify_access(file);
> + err = nfs_ok;
> + } else {
> + trace_nfsd_read_err(rqstp, fhp, offset, host_err);
> + err = nfserrno(host_err);
> + }
>
> if (ra)
> nfsd_put_raparams(file, ra);
> diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
> index be6d8e0..d9131c3 100644
> --- a/fs/nfsd/vfs.h
> +++ b/fs/nfsd/vfs.h
> @@ -78,10 +78,10 @@ __be32 nfsd_commit(struct svc_rqst *, struct svc_fh *,
> __be32 nfsd_open(struct svc_rqst *, struct svc_fh *, umode_t,
> int, struct file **);
> struct raparms;
> -__be32 nfsd_splice_read(struct svc_rqst *,
> - struct file *, loff_t, unsigned long *);
> -__be32 nfsd_readv(struct file *, loff_t, struct kvec *, int,
> - unsigned long *);
> +int nfsd_splice_read(struct svc_rqst *rqstp, struct file *file,
> + loff_t offset, unsigned long *count);
> +int nfsd_readv(struct file *file, loff_t offset, struct kvec *vec,
> + int vlen, unsigned long *count);
> __be32 nfsd_read(struct svc_rqst *, struct svc_fh *,
> loff_t, struct kvec *, int, unsigned long *);
> __be32 nfsd_write(struct svc_rqst *, struct svc_fh *, loff_t,
>
> --
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--
Chuck Lever
--
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