nfsd: use short read as well as i_size to set eof

Use the result of a local read to determine when to set the eof flag.  This
allows us to return the location of the end of the file atomically at the
time of the read.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
[bfields: add some documentation]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index aa87954b4af2..9df898ba648f 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3365,6 +3365,7 @@ static __be32 nfsd4_encode_splice_read(
         struct xdr_stream *xdr = &resp->xdr;
         struct xdr_buf *buf = xdr->buf;
         u32 eof;
+        long len;
         int space_left;
         __be32 nfserr;
         __be32 *p = xdr->p - 2;
@@ -3373,6 +3374,7 @@ static __be32 nfsd4_encode_splice_read(
         if (xdr->end - xdr->p < 1)
                 return nfserr_resource;
 
+        len = maxcount;
         nfserr = nfsd_splice_read(read->rd_rqstp, file,
                                   read->rd_offset, &maxcount);
         if (nfserr) {
@@ -3385,8 +3387,8 @@ static __be32 nfsd4_encode_splice_read(
                 return nfserr;
         }
 
-        eof = (read->rd_offset + maxcount >=
-               d_inode(read->rd_fhp->fh_dentry)->i_size);
+        eof = nfsd_eof_on_read(len, maxcount, read->rd_offset,
+                                d_inode(read->rd_fhp->fh_dentry)->i_size);
 
         *(p++) = htonl(eof);
         *(p++) = htonl(maxcount);
@@ -3456,14 +3458,15 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
         }
         read->rd_vlen = v;
 
+        len = maxcount;
         nfserr = nfsd_readv(file, read->rd_offset, resp->rqstp->rq_vec,
                         read->rd_vlen, &maxcount);
         if (nfserr)
                 return nfserr;
         xdr_truncate_encode(xdr, starting_len + 8 + ((maxcount+3)&~3));
 
-        eof = (read->rd_offset + maxcount >=
-               d_inode(read->rd_fhp->fh_dentry)->i_size);
+        eof = nfsd_eof_on_read(len, maxcount, read->rd_offset,
+                                d_inode(read->rd_fhp->fh_dentry)->i_size);
 
         tmp = htonl(eof);
         write_bytes_to_xdr_buf(xdr->buf, starting_len    , &tmp, 4);