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Message-ID: <508567C7.6000104@oracle.com>
Date: Mon, 22 Oct 2012 10:35:35 -0500
From: Dave Kleikamp <dave.kleikamp@...cle.com>
To: "Myklebust, Trond" <Trond.Myklebust@...app.com>
CC: "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Zach Brown <zab@...bo.net>,
"Maxim V. Patlasov" <mpatlasov@...allels.com>,
"linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>
Subject: Re: [PATCH 20/22] nfs: add support for read_iter, write_iter
On 10/22/2012 10:21 AM, Myklebust, Trond wrote:
>> -----Original Message-----
>> From: Dave Kleikamp [mailto:dave.kleikamp@...cle.com]
>> Sent: Monday, October 22, 2012 11:15 AM
>> To: linux-fsdevel@...r.kernel.org
>> Cc: linux-kernel@...r.kernel.org; Zach Brown; Maxim V. Patlasov; Dave
>> Kleikamp; Myklebust, Trond; linux-nfs@...r.kernel.org
>> Subject: [PATCH 20/22] nfs: add support for read_iter, write_iter
>>
>> This patch implements the read_iter and write_iter file operations which
>> allow kernel code to initiate directIO. This allows the loop device to read and
>> write directly to the server, bypassing the page cache.
>>
>> Signed-off-by: Dave Kleikamp <dave.kleikamp@...cle.com>
>> Cc: Zach Brown <zab@...bo.net>
>> Cc: Trond Myklebust <Trond.Myklebust@...app.com>
>> Cc: linux-nfs@...r.kernel.org
>> ---
>> fs/nfs/direct.c | 169 +++++++++++++++++++++++++++++++++-----------
>> -----
>> fs/nfs/file.c | 48 ++++++++++----
>> fs/nfs/internal.h | 2 +
>> fs/nfs/nfs4file.c | 2 +
>> include/linux/nfs_fs.h | 6 +-
>> 5 files changed, 155 insertions(+), 72 deletions(-)
>>
>> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 4532781..b1fda1c 100644
>> --- a/fs/nfs/direct.c
>> +++ b/fs/nfs/direct.c
>> @@ -429,16 +428,47 @@ static ssize_t
>> nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
>> get_dreq(dreq);
>> desc.pg_dreq = dreq;
>>
>> - for (seg = 0; seg < nr_segs; seg++) {
>> - const struct iovec *vec = &iov[seg];
>> - result = nfs_direct_read_schedule_segment(&desc, vec,
>> pos, uio);
>> - if (result < 0)
>> - break;
>> - requested_bytes += result;
>> - if ((size_t)result < vec->iov_len)
>> - break;
>> - pos += vec->iov_len;
>> - }
>> + if (iov_iter_has_iovec(iter)) {
>> + const struct iovec *iov = iov_iter_iovec(iter);
>> + if (uio)
>> + dreq->flags = NFS_ODIRECT_MARK_DIRTY;
>> + for (seg = 0; seg < iter->nr_segs; seg++) {
>> + const struct iovec *vec = &iov[seg];
>> + result = nfs_direct_read_schedule_segment(&desc,
>> vec,
>> + pos, uio);
>> + if (result < 0)
>> + break;
>> + requested_bytes += result;
>> + if ((size_t)result < vec->iov_len)
>> + break;
>> + pos += vec->iov_len;
>> + }
>> + } else if (iov_iter_has_bvec(iter)) {
>> + struct nfs_open_context *ctx = dreq->ctx;
>> + struct inode *inode = ctx->dentry->d_inode;
>> + struct bio_vec *bvec = iov_iter_bvec(iter);
>> + for (seg = 0; seg < iter->nr_segs; seg++) {
>> + struct nfs_page *req;
>> + unsigned int req_len = bvec[seg].bv_len;
>> + req = nfs_create_request(ctx, inode,
>> + bvec[seg].bv_page,
>> + bvec[seg].bv_offset,
>> req_len);
>> + if (IS_ERR(req)) {
>> + result = PTR_ERR(req);
>> + break;
>> + }
>> + req->wb_index = pos >> PAGE_SHIFT;
>> + req->wb_offset = pos & ~PAGE_MASK;
>> + if (!nfs_pageio_add_request(&desc, req)) {
>> + result = desc.pg_error;
>> + nfs_release_request(req);
>> + break;
>> + }
>> + requested_bytes += req_len;
>> + pos += req_len;
>> + }
>> + } else
>> + BUG();
>
> Can we please split the contents of these 2 if statements into 2 helper functions nfs_direct_do_schedule_read_iovec() and nfs_direct_do_schedule_read_bvec()?
>
Sure, no problem.
>> @@ -832,17 +861,48 @@ static ssize_t
>> nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
>> get_dreq(dreq);
>> atomic_inc(&inode->i_dio_count);
>>
>> - NFS_I(dreq->inode)->write_io += iov_length(iov, nr_segs);
>> - for (seg = 0; seg < nr_segs; seg++) {
>> - const struct iovec *vec = &iov[seg];
>> - result = nfs_direct_write_schedule_segment(&desc, vec,
>> pos, uio);
>> - if (result < 0)
>> - break;
>> - requested_bytes += result;
>> - if ((size_t)result < vec->iov_len)
>> - break;
>> - pos += vec->iov_len;
>> - }
>> + NFS_I(dreq->inode)->write_io += iov_iter_count(iter);
>> +
>> + if (iov_iter_has_iovec(iter)) {
>> + const struct iovec *iov = iov_iter_iovec(iter);
>> + for (seg = 0; seg < iter->nr_segs; seg++) {
>> + const struct iovec *vec = &iov[seg];
>> + result = nfs_direct_write_schedule_segment(&desc,
>> vec,
>> + pos, uio);
>> + if (result < 0)
>> + break;
>> + requested_bytes += result;
>> + if ((size_t)result < vec->iov_len)
>> + break;
>> + pos += vec->iov_len;
>> + }
>> + } else if (iov_iter_has_bvec(iter)) {
>> + struct nfs_open_context *ctx = dreq->ctx;
>> + struct bio_vec *bvec = iov_iter_bvec(iter);
>> + for (seg = 0; seg < iter->nr_segs; seg++) {
>> + struct nfs_page *req;
>> + unsigned int req_len = bvec[seg].bv_len;
>> +
>> + req = nfs_create_request(ctx, inode,
>> bvec[seg].bv_page,
>> + bvec[seg].bv_offset,
>> req_len);
>> + if (IS_ERR(req)) {
>> + result = PTR_ERR(req);
>> + break;
>> + }
>> + nfs_lock_request(req);
>> + req->wb_index = pos >> PAGE_SHIFT;
>> + req->wb_offset = pos & ~PAGE_MASK;
>> + if (!nfs_pageio_add_request(&desc, req)) {
>> + result = desc.pg_error;
>> + nfs_unlock_and_release_request(req);
>> + break;
>> + }
>> + requested_bytes += req_len;
>> + pos += req_len;
>> + }
>> + } else
>> + BUG();
>
> Ditto...
ok
>
> Otherwise, everything looks fine to me...
>
> Acked-by: Trond Myklebust <Trond.Myklebust@...app.com>
>
> Cheers
> Trond
Thanks,
Shaggy
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