diff mbox

[6/8] nfs: don't dirty ITER_BVEC pages read through direct I/O

Message ID e5240b33c30d147588d0cdd285d8d95463b3de18.1418618044.git.osandov@osandov.com (mailing list archive)
State New, archived
Headers show

Commit Message

Omar Sandoval Dec. 15, 2014, 5:27 a.m. UTC 
As with the generic blockdev code, kernel pages shouldn't be dirtied by
the direct I/O path.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
---
 fs/nfs/direct.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Al Viro Dec. 15, 2014, 6:17 a.m. UTC | #1 
On Sun, Dec 14, 2014 at 09:27:00PM -0800, Omar Sandoval wrote:
> As with the generic blockdev code, kernel pages shouldn't be dirtied by
> the direct I/O path.

This really asks for an inlined helper (iter_is_bvec(iter) or something like
that)
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diff mbox

Patch

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 9402b96..a502b3f 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -88,6 +88,7 @@  struct nfs_direct_req {
 	struct pnfs_ds_commit_info ds_cinfo;	/* Storage for cinfo */
 	struct work_struct	work;
 	int			flags;
+	int			should_dirty;	/* should we mark read pages dirty? */
 #define NFS_ODIRECT_DO_COMMIT		(1)	/* an unstable reply was received */
 #define NFS_ODIRECT_RESCHED_WRITES	(2)	/* write verification failed */
 	struct nfs_writeverf	verf;		/* unstable write verifier */
@@ -370,7 +371,8 @@  static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
 		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 		struct page *page = req->wb_page;
 
-		if (!PageCompound(page) && bytes < hdr->good_bytes)
+		if (!PageCompound(page) && bytes < hdr->good_bytes &&
+		    dreq->should_dirty)
 			set_page_dirty(page);
 		bytes += req->wb_bytes;
 		nfs_list_remove_request(req);
@@ -542,6 +544,7 @@  ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
 	dreq->inode = inode;
 	dreq->bytes_left = count;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
+	dreq->should_dirty = !(iter->type & ITER_BVEC);
 	l_ctx = nfs_get_lock_context(dreq->ctx);
 	if (IS_ERR(l_ctx)) {
 		result = PTR_ERR(l_ctx);