pNFS: Fix the pnfs block driver's calculation of layoutget size

[ Upstream commit 8a6291bf3b0eae1bf26621e6419a91682f2d6227 ]

Instead of relying on the value of the 'bytes_left' field, we should
calculate the layout size based on the offset of the request that is
being written out.

Reported-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Fixes: 954998b60caa ("NFS: Fix error handling for O_DIRECT write scheduling")
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 1d1d7ab..6be13e0 100644 (file)
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -895,10 +895,9 @@ bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
        }
 
        if (pgio->pg_dreq == NULL)
-               wb_size = pnfs_num_cont_bytes(pgio->pg_inode,
-                                             req->wb_index);
+               wb_size = pnfs_num_cont_bytes(pgio->pg_inode, req->wb_index);
        else
-               wb_size = nfs_dreq_bytes_left(pgio->pg_dreq);
+               wb_size = nfs_dreq_bytes_left(pgio->pg_dreq, req_offset(req));
 
        pnfs_generic_pg_init_write(pgio, req, wb_size);
 

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index f6c74f4..5918c67 100644 (file)
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -205,9 +205,10 @@ static void nfs_direct_req_release(struct nfs_direct_req *dreq)
        kref_put(&dreq->kref, nfs_direct_req_free);
 }
 
-ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq)
+ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq, loff_t offset)
 {
-       return dreq->bytes_left;
+       loff_t start = offset - dreq->io_start;
+       return dreq->max_count - start;
 }
 EXPORT_SYMBOL_GPL(nfs_dreq_bytes_left);
 

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 9c9cf76..b1fa81c 100644 (file)
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -655,7 +655,7 @@ extern int nfs_sillyrename(struct inode *dir, struct dentry *dentry);
 /* direct.c */
 void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
                              struct nfs_direct_req *dreq);
-extern ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq);
+extern ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq, loff_t offset);
 
 /* nfs4proc.c */
 extern struct nfs_client *nfs4_init_client(struct nfs_client *clp,

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 84343ae..9084f15 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -2729,7 +2729,8 @@ pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *r
                if (pgio->pg_dreq == NULL)
                        rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
                else
-                       rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
+                       rd_size = nfs_dreq_bytes_left(pgio->pg_dreq,
+                                                     req_offset(req));
 
                pgio->pg_lseg =
                        pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),