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nfsd: Add I/O trace points in the NFSv4 write path

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NFSv4 write compound processing invokes nfsd_vfs_write directly. The
trace points currently in nfsd_write are not effective for NFSv4
writes.

Move the trace points into the shared nfsd_vfs_write() helper.

After the I/O, we also want to record any local I/O error that
might have occurred, and the total count of bytes that were actually
moved (rather than the requested number).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Chuck Lever 2018-03-27 10:53:27 -04:00 committed by J. Bruce Fields
parent f394b62b7b
commit d890be159a
3 changed files with 50 additions and 13 deletions
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7
fs/nfsd/nfs4proc.c
View File

@ -1001,6 +1001,9 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
if (write->wr_offset >= OFFSET_MAX)
return nfserr_inval;
cnt = write->wr_buflen;
trace_nfsd_write_start(rqstp, &cstate->current_fh,
write->wr_offset, cnt);
status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh,
stateid, WR_STATE, &filp, NULL);
if (status) {
@ -1008,7 +1011,6 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
return status;
}
cnt = write->wr_buflen;
write->wr_how_written = write->wr_stable_how;
gen_boot_verifier(&write->wr_verifier, SVC_NET(rqstp));
@ -1021,7 +1023,8 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
fput(filp);
write->wr_bytes_written = cnt;
trace_nfsd_write_done(rqstp, &cstate->current_fh,
write->wr_offset, cnt);
return status;
}

33
fs/nfsd/trace.h
View File

@ -51,6 +51,39 @@ DEFINE_NFSD_IO_EVENT(write_opened);
DEFINE_NFSD_IO_EVENT(write_io_done);
DEFINE_NFSD_IO_EVENT(write_done);
DECLARE_EVENT_CLASS(nfsd_err_class,
TP_PROTO(struct svc_rqst *rqstp,
struct svc_fh *fhp,
loff_t offset,
int status),
TP_ARGS(rqstp, fhp, offset, status),
TP_STRUCT__entry(
__field(u32, xid)
__field(u32, fh_hash)
__field(loff_t, offset)
__field(int, status)
),
TP_fast_assign(
__entry->xid = be32_to_cpu(rqstp->rq_xid);
__entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
__entry->offset = offset;
__entry->status = status;
),
TP_printk("xid=0x%08x fh_hash=0x%08x offset=%lld status=%d",
__entry->xid, __entry->fh_hash,
__entry->offset, __entry->status)
)
#define DEFINE_NFSD_ERR_EVENT(name) \
DEFINE_EVENT(nfsd_err_class, nfsd_##name, \
TP_PROTO(struct svc_rqst *rqstp, \
struct svc_fh *fhp, \
loff_t offset, \
int len), \
TP_ARGS(rqstp, fhp, offset, len))
DEFINE_NFSD_ERR_EVENT(write_err);
#include "state.h"
DECLARE_EVENT_CLASS(nfsd_stateid_class,

23
fs/nfsd/vfs.c
View File

@ -965,13 +965,15 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
{
struct svc_export *exp;
struct iov_iter iter;
__be32 err = 0;
__be32 nfserr;
int host_err;
int use_wgather;
loff_t pos = offset;
unsigned int pflags = current->flags;
rwf_t flags = 0;
trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
/*
* We want less throttling in balance_dirty_pages()
@ -994,22 +996,23 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
host_err = vfs_iter_write(file, &iter, &pos, flags);
if (host_err < 0)
goto out_nfserr;
*cnt = host_err;
nfsdstats.io_write += host_err;
nfsdstats.io_write += *cnt;
fsnotify_modify(file);
if (stable && use_wgather)
host_err = wait_for_concurrent_writes(file);
out_nfserr:
dprintk("nfsd: write complete host_err=%d\n", host_err);
if (host_err >= 0)
err = 0;
else
err = nfserrno(host_err);
if (host_err >= 0) {
trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
nfserr = nfs_ok;
} else {
trace_nfsd_write_err(rqstp, fhp, offset, host_err);
nfserr = nfserrno(host_err);
}
if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
current_restore_flags(pflags, PF_LESS_THROTTLE);
return err;
return nfserr;
}
/*
@ -1067,9 +1070,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset,
if (err)
goto out;
trace_nfsd_write_opened(rqstp, fhp, offset, *cnt);
err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt, stable);
trace_nfsd_write_io_done(rqstp, fhp, offset, *cnt);
fput(file);
out:
trace_nfsd_write_done(rqstp, fhp, offset, *cnt);