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NFS: Trace short NFS READs

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A short read can generate an -EIO error without there being an error
on the wire. This tracepoint acts as an eyecatcher when there is no
obvious I/O error.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2020-05-12 17:14:05 -04:00 committed by Anna Schumaker
parent 5be5945864
commit fd2b612141
2 changed files with 49 additions and 0 deletions
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47
fs/nfs/nfstrace.h
View File

@ -961,6 +961,53 @@ TRACE_EVENT(nfs_readpage_done,
)
);
TRACE_EVENT(nfs_readpage_short,
TP_PROTO(
const struct rpc_task *task,
const struct nfs_pgio_header *hdr
),
TP_ARGS(task, hdr),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(u32, fhandle)
__field(u64, fileid)
__field(loff_t, offset)
__field(u32, arg_count)
__field(u32, res_count)
__field(bool, eof)
__field(int, status)
),
TP_fast_assign(
const struct inode *inode = hdr->inode;
const struct nfs_inode *nfsi = NFS_I(inode);
const struct nfs_fh *fh = hdr->args.fh ?
hdr->args.fh : &nfsi->fh;
__entry->status = task->tk_status;
__entry->offset = hdr->args.offset;
__entry->arg_count = hdr->args.count;
__entry->res_count = hdr->res.count;
__entry->eof = hdr->res.eof;
__entry->dev = inode->i_sb->s_dev;
__entry->fileid = nfsi->fileid;
__entry->fhandle = nfs_fhandle_hash(fh);
),
TP_printk(
"fileid=%02x:%02x:%llu fhandle=0x%08x "
"offset=%lld count=%u res=%u status=%d%s",
MAJOR(__entry->dev), MINOR(__entry->dev),
(unsigned long long)__entry->fileid,
__entry->fhandle,
(long long)__entry->offset, __entry->arg_count,
__entry->res_count, __entry->status,
__entry->eof ? " eof" : ""
)
);
TRACE_DEFINE_ENUM(NFS_UNSTABLE);
TRACE_DEFINE_ENUM(NFS_DATA_SYNC);
TRACE_DEFINE_ENUM(NFS_FILE_SYNC);

2
fs/nfs/read.c
View File

@ -264,6 +264,8 @@ static void nfs_readpage_retry(struct rpc_task *task,
/* This is a short read! */
nfs_inc_stats(hdr->inode, NFSIOS_SHORTREAD);
trace_nfs_readpage_short(task, hdr);
/* Has the server at least made some progress? */
if (resp->count == 0) {
nfs_set_pgio_error(hdr, -EIO, argp->offset);