* 18 Dec 2001 Initial implementation for 2.4 --cel
* 08 Jul 2002 Version for 2.4.19, with bug fixes --trondmy
* 08 Jun 2003 Port to 2.5 APIs --cel
+ * 31 Mar 2004 Handle direct I/O without VFS support --cel
*
*/
{
const unsigned int wsize = NFS_SERVER(inode)->wsize;
size_t request;
- int need_commit;
- int tot_bytes;
- int curpage;
+ int curpage, need_commit, result, tot_bytes;
struct nfs_writeverf first_verf;
struct nfs_write_data wdata = {
.inode = inode,
wdata.args.pgbase = user_addr & ~PAGE_MASK;
wdata.args.offset = file_offset;
do {
- int result;
-
wdata.args.count = request;
if (wdata.args.count > wsize)
wdata.args.count = wsize;
if (result <= 0) {
if (tot_bytes > 0)
break;
- return result;
+ goto out;
}
if (tot_bytes == 0)
* Commit data written so far, even in the event of an error
*/
if (need_commit) {
- int result;
-
wdata.args.count = tot_bytes;
wdata.args.offset = file_offset;
VERF_SIZE) != 0)
goto sync_retry;
}
+ result = tot_bytes;
+
+out:
nfs_end_data_update_defer(inode);
- return tot_bytes;
+ return result;
sync_retry:
wdata.args.stable = NFS_FILE_SYNC;
* file_offset: offset in file to begin the operation
* nr_segs: size of iovec array
*
- * Usually a file system implements direct I/O by calling out to
- * blockdev_direct_IO. The NFS client doesn't have a backing block
- * device, so we do everything by hand instead.
- *
- * The inode's i_sem is no longer held by the VFS layer before it calls
- * this function to do a write.
*/
ssize_t
nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
* No support for async yet
*/
if (!is_sync_kiocb(iocb))
- goto out;
-
- result = nfs_revalidate_inode(NFS_SERVER(inode), inode);
- if (result < 0)
- goto out;
+ return result;
switch (rw) {
case READ:
default:
break;
}
+ return result;
+}
+
+/**
+ * nfs_file_direct_read - file direct read operation for NFS files
+ * @iocb: target I/O control block
+ * @buf: user's buffer into which to read data
+ * count: number of bytes to read
+ * pos: byte offset in file where reading starts
+ *
+ * We use this function for direct reads instead of calling
+ * generic_file_aio_read() in order to avoid gfar's check to see if
+ * the request starts before the end of the file. For that check
+ * to work, we must generate a GETATTR before each direct read, and
+ * even then there is a window between the GETATTR and the subsequent
+ * READ where the file size could change. So our preference is simply
+ * to do all reads the application wants, and the server will take
+ * care of managing the end of file boundary.
+ *
+ * This function also eliminates unnecessarily updating the file's
+ * atime locally, as the NFS server sets the file's atime, and this
+ * client must read the updated atime from the server back into its
+ * cache.
+ */
+ssize_t
+nfs_file_direct_read(struct kiocb *iocb, char __user *buf, size_t count, loff_t pos)
+{
+ ssize_t retval = -EINVAL;
+ loff_t *ppos = &iocb->ki_pos;
+ struct file *file = iocb->ki_filp;
+ struct dentry *dentry = file->f_dentry;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ struct iovec iov = {
+ .iov_base = (char *)buf,
+ .iov_len = count,
+ };
+
+ dprintk("nfs: direct read(%s/%s, %lu@%lu)\n",
+ dentry->d_parent->d_name.name, dentry->d_name.name,
+ (unsigned long) count, (unsigned long) pos);
+
+ if (!is_sync_kiocb(iocb))
+ goto out;
+ if (count < 0)
+ goto out;
+ retval = -EFAULT;
+ if (!access_ok(VERIFY_WRITE, iov.iov_base, iov.iov_len))
+ goto out;
+ retval = 0;
+ if (!count)
+ goto out;
+
+ if (mapping->nrpages) {
+ retval = filemap_fdatawrite(mapping);
+ if (retval == 0)
+ retval = filemap_fdatawait(mapping);
+ if (retval)
+ goto out;
+ }
+
+ retval = nfs_direct_read(inode, file, &iov, pos, 1);
+ if (retval > 0)
+ *ppos = pos + retval;
out:
- dprintk("NFS: direct_IO result=%zd\n", result);
- return result;
+ return retval;
+}
+
+/**
+ * nfs_file_direct_write - file direct write operation for NFS files
+ * @iocb: target I/O control block
+ * @buf: user's buffer from which to write data
+ * count: number of bytes to write
+ * pos: byte offset in file where writing starts
+ *
+ * We use this function for direct writes instead of calling
+ * generic_file_aio_write() in order to avoid taking the inode
+ * semaphore and updating the i_size. The NFS server will set
+ * the new i_size and this client must read the updated size
+ * back into its cache. We let the server do generic write
+ * parameter checking and report problems.
+ *
+ * We also avoid an unnecessary invocation of generic_osync_inode(),
+ * as it is fairly meaningless to sync the metadata of an NFS file.
+ *
+ * We eliminate local atime updates, see direct read above.
+ *
+ * We avoid unnecessary page cache invalidations for normal cached
+ * readers of this file.
+ *
+ * Note that O_APPEND is not supported for NFS direct writes, as there
+ * is no atomic O_APPEND write facility in the NFS protocol.
+ */
+ssize_t
+nfs_file_direct_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos)
+{
+ ssize_t retval = -EINVAL;
+ loff_t *ppos = &iocb->ki_pos;
+ unsigned long limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
+ struct file *file = iocb->ki_filp;
+ struct dentry *dentry = file->f_dentry;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ struct iovec iov = {
+ .iov_base = (char __user *)buf,
+ .iov_len = count,
+ };
+
+ dfprintk(VFS, "nfs: direct write(%s/%s(%ld), %lu@%lu)\n",
+ dentry->d_parent->d_name.name, dentry->d_name.name,
+ inode->i_ino, (unsigned long) count, (unsigned long) pos);
+
+ if (!is_sync_kiocb(iocb))
+ goto out;
+ if (count < 0)
+ goto out;
+ if (pos < 0)
+ goto out;
+ retval = -EFAULT;
+ if (!access_ok(VERIFY_READ, iov.iov_base, iov.iov_len))
+ goto out;
+ if (file->f_error) {
+ retval = file->f_error;
+ file->f_error = 0;
+ goto out;
+ }
+ retval = -EFBIG;
+ if (limit != RLIM_INFINITY) {
+ if (pos >= limit) {
+ send_sig(SIGXFSZ, current, 0);
+ goto out;
+ }
+ if (count > limit - (unsigned long) pos)
+ count = limit - (unsigned long) pos;
+ }
+ retval = 0;
+ if (!count)
+ goto out;
+
+ if (mapping->nrpages) {
+ retval = filemap_fdatawrite(mapping);
+ if (retval == 0)
+ retval = filemap_fdatawait(mapping);
+ if (retval)
+ goto out;
+ }
+
+ retval = nfs_direct_write(inode, file, &iov, pos, 1);
+ if (mapping->nrpages)
+ invalidate_inode_pages2(mapping);
+ if (retval > 0)
+ *ppos = pos + retval;
+
+out:
+ return retval;
}
git://git.onelab.eu / linux-2.6.git / blobdiff