NFS: Add support for eager writes

Support eager writing to the server, meaning that we write the data to
cache on the server, and wait for that to complete. This ensures that we
see ENOSPC errors immediately.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 03fd1dc..16ad505 100644 (file)
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -606,8 +606,8 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 {
        struct file *file = iocb->ki_filp;
        struct inode *inode = file_inode(file);
-       unsigned long written = 0;
-       ssize_t result;
+       unsigned int mntflags = NFS_SERVER(inode)->flags;
+       ssize_t result, written;
        errseq_t since;
        int error;
 
@@ -648,6 +648,21 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 
        written = result;
        iocb->ki_pos += written;
+
+       if (mntflags & NFS_MOUNT_WRITE_EAGER) {
+               result = filemap_fdatawrite_range(file->f_mapping,
+                                                 iocb->ki_pos - written,
+                                                 iocb->ki_pos - 1);
+               if (result < 0)
+                       goto out;
+       }
+       if (mntflags & NFS_MOUNT_WRITE_WAIT) {
+               result = filemap_fdatawait_range(file->f_mapping,
+                                                iocb->ki_pos - written,
+                                                iocb->ki_pos - 1);
+               if (result < 0)
+                       goto out;
+       }
        result = generic_write_sync(iocb, written);
        if (result < 0)
                goto out;

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 6193350..82bdcb9 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -712,16 +712,23 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 {
        struct inode *inode = mapping->host;
        struct nfs_pageio_descriptor pgio;
-       struct nfs_io_completion *ioc;
+       struct nfs_io_completion *ioc = NULL;
+       unsigned int mntflags = NFS_SERVER(inode)->flags;
+       int priority = 0;
        int err;
 
        nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 
-       ioc = nfs_io_completion_alloc(GFP_KERNEL);
-       if (ioc)
-               nfs_io_completion_init(ioc, nfs_io_completion_commit, inode);
+       if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
+           wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
+               ioc = nfs_io_completion_alloc(GFP_KERNEL);
+               if (ioc)
+                       nfs_io_completion_init(ioc, nfs_io_completion_commit,
+                                              inode);
+               priority = wb_priority(wbc);
+       }
 
-       nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false,
+       nfs_pageio_init_write(&pgio, inode, priority, false,
                                &nfs_async_write_completion_ops);
        pgio.pg_io_completion = ioc;
        err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);

diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 962e831..6f76b32 100644 (file)
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -153,6 +153,8 @@ struct nfs_server {
 #define NFS_MOUNT_LOCAL_FCNTL          0x200000
 #define NFS_MOUNT_SOFTERR              0x400000
 #define NFS_MOUNT_SOFTREVAL            0x800000
+#define NFS_MOUNT_WRITE_EAGER          0x01000000
+#define NFS_MOUNT_WRITE_WAIT           0x02000000
 
        unsigned int            caps;           /* server capabilities */
        unsigned int            rsize;          /* read size */