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NFSD: Simplify READ_PLUS

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[ Upstream commit eeadcb75794516839078c28b3730132aeb700ce6 ]

Chuck had suggested reverting READ_PLUS so it returns a single DATA
segment covering the requested read range. This prepares the server for
a future "sparse read" function so support can easily be added without
needing to rip out the old READ_PLUS code at the same time.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Anna Schumaker 2022-09-13 14:01:51 -04:00 committed by Greg Kroah-Hartman
parent 10727ce312
commit 48a237cb5e
1 changed files with 32 additions and 107 deletions
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139
fs/nfsd/nfs4xdr.c
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@ -4775,79 +4775,37 @@ nfsd4_encode_offload_status(struct nfsd4_compoundres *resp, __be32 nfserr,
static __be32
nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
struct nfsd4_read *read,
unsigned long *maxcount, u32 *eof,
loff_t *pos)
struct nfsd4_read *read)
{
struct xdr_stream *xdr = resp->xdr;
bool splice_ok = test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags);
struct file *file = read->rd_nf->nf_file;
int starting_len = xdr->buf->len;
loff_t hole_pos;
__be32 nfserr;
__be32 *p, tmp;
__be64 tmp64;
hole_pos = pos ? *pos : vfs_llseek(file, read->rd_offset, SEEK_HOLE);
if (hole_pos > read->rd_offset)
*maxcount = min_t(unsigned long, *maxcount, hole_pos - read->rd_offset);
*maxcount = min_t(unsigned long, *maxcount, (xdr->buf->buflen - xdr->buf->len));
struct xdr_stream *xdr = resp->xdr;
unsigned long maxcount;
__be32 nfserr, *p;
/* Content type, offset, byte count */
p = xdr_reserve_space(xdr, 4 + 8 + 4);
if (!p)
return nfserr_resource;
return nfserr_io;
if (resp->xdr->buf->page_len && splice_ok) {
WARN_ON_ONCE(splice_ok);
return nfserr_serverfault;
}
read->rd_vlen = xdr_reserve_space_vec(xdr, resp->rqstp->rq_vec, *maxcount);
if (read->rd_vlen < 0)
return nfserr_resource;
maxcount = min_t(unsigned long, read->rd_length,
(xdr->buf->buflen - xdr->buf->len));
nfserr = nfsd_readv(resp->rqstp, read->rd_fhp, file, read->rd_offset,
resp->rqstp->rq_vec, read->rd_vlen, maxcount, eof);
if (file->f_op->splice_read && splice_ok)
nfserr = nfsd4_encode_splice_read(resp, read, file, maxcount);
else
nfserr = nfsd4_encode_readv(resp, read, file, maxcount);
if (nfserr)
return nfserr;
xdr_truncate_encode(xdr, starting_len + 16 + xdr_align_size(*maxcount));
tmp = htonl(NFS4_CONTENT_DATA);
write_bytes_to_xdr_buf(xdr->buf, starting_len, &tmp, 4);
tmp64 = cpu_to_be64(read->rd_offset);
write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp64, 8);
tmp = htonl(*maxcount);
write_bytes_to_xdr_buf(xdr->buf, starting_len + 12, &tmp, 4);
tmp = xdr_zero;
write_bytes_to_xdr_buf(xdr->buf, starting_len + 16 + *maxcount, &tmp,
xdr_pad_size(*maxcount));
return nfs_ok;
}
static __be32
nfsd4_encode_read_plus_hole(struct nfsd4_compoundres *resp,
struct nfsd4_read *read,
unsigned long *maxcount, u32 *eof)
{
struct file *file = read->rd_nf->nf_file;
loff_t data_pos = vfs_llseek(file, read->rd_offset, SEEK_DATA);
loff_t f_size = i_size_read(file_inode(file));
unsigned long count;
__be32 *p;
if (data_pos == -ENXIO)
data_pos = f_size;
else if (data_pos <= read->rd_offset || (data_pos < f_size && data_pos % PAGE_SIZE))
return nfsd4_encode_read_plus_data(resp, read, maxcount, eof, &f_size);
count = data_pos - read->rd_offset;
/* Content type, offset, byte count */
p = xdr_reserve_space(resp->xdr, 4 + 8 + 8);
if (!p)
return nfserr_resource;
*p++ = htonl(NFS4_CONTENT_HOLE);
*p++ = cpu_to_be32(NFS4_CONTENT_DATA);
p = xdr_encode_hyper(p, read->rd_offset);
p = xdr_encode_hyper(p, count);
*p = cpu_to_be32(read->rd_length);
*eof = (read->rd_offset + count) >= f_size;
*maxcount = min_t(unsigned long, count, *maxcount);
return nfs_ok;
}
@ -4855,69 +4813,36 @@ static __be32
nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr,
struct nfsd4_read *read)
{
unsigned long maxcount, count;
struct file *file = read->rd_nf->nf_file;
struct xdr_stream *xdr = resp->xdr;
struct file *file;
int starting_len = xdr->buf->len;
int last_segment = xdr->buf->len;
int segments = 0;
__be32 *p, tmp;
bool is_data;
loff_t pos;
u32 eof;
u32 segments = 0;
__be32 *p;
if (nfserr)
return nfserr;
file = read->rd_nf->nf_file;
/* eof flag, segment count */
p = xdr_reserve_space(xdr, 4 + 4);
if (!p)
return nfserr_resource;
return nfserr_io;
xdr_commit_encode(xdr);
maxcount = min_t(unsigned long, read->rd_length,
(xdr->buf->buflen - xdr->buf->len));
count = maxcount;
eof = read->rd_offset >= i_size_read(file_inode(file));
if (eof)
read->rd_eof = read->rd_offset >= i_size_read(file_inode(file));
if (read->rd_eof)
goto out;
pos = vfs_llseek(file, read->rd_offset, SEEK_HOLE);
is_data = pos > read->rd_offset;
while (count > 0 && !eof) {
maxcount = count;
if (is_data)
nfserr = nfsd4_encode_read_plus_data(resp, read, &maxcount, &eof,
segments == 0 ? &pos : NULL);
else
nfserr = nfsd4_encode_read_plus_hole(resp, read, &maxcount, &eof);
if (nfserr)
goto out;
count -= maxcount;
read->rd_offset += maxcount;
is_data = !is_data;
last_segment = xdr->buf->len;
segments++;
nfserr = nfsd4_encode_read_plus_data(resp, read);
if (nfserr) {
xdr_truncate_encode(xdr, starting_len);
return nfserr;
}
segments++;
out:
if (nfserr && segments == 0)
xdr_truncate_encode(xdr, starting_len);
else {
if (nfserr) {
xdr_truncate_encode(xdr, last_segment);
nfserr = nfs_ok;
eof = 0;
}
tmp = htonl(eof);
write_bytes_to_xdr_buf(xdr->buf, starting_len, &tmp, 4);
tmp = htonl(segments);
write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);
}
p = xdr_encode_bool(p, read->rd_eof);
*p = cpu_to_be32(segments);
return nfserr;
}