fs/orangefs/file.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * (C) 2001 Clemson University and The University of Chicago
  * Copyright 2018 Omnibond Systems, L.L.C.
  *
  * See COPYING in top-level directory.
  */

 /*
  *  Linux VFS file operations.
  */

 #include "protocol.h"
 #include "orangefs-kernel.h"
 #include "orangefs-bufmap.h"
 #include <linux/fs.h>
 #include <linux/filelock.h>
 #include <linux/pagemap.h>

 static int flush_racache(struct inode *inode)
 {
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct orangefs_kernel_op_s *new_op;
 	int ret;

 	gossip_debug(GOSSIP_UTILS_DEBUG,
 	    "%s: %pU: Handle is %pU | fs_id %d\n", __func__,
 	    get_khandle_from_ino(inode), &orangefs_inode->refn.khandle,
 	    orangefs_inode->refn.fs_id);

 	new_op = op_alloc(ORANGEFS_VFS_OP_RA_FLUSH);
 	if (!new_op)
 		return -ENOMEM;
 	new_op->upcall.req.ra_cache_flush.refn = orangefs_inode->refn;

 	ret = service_operation(new_op, "orangefs_flush_racache",
 	    get_interruptible_flag(inode));

 	gossip_debug(GOSSIP_UTILS_DEBUG, "%s: got return value of %d\n",
 	    __func__, ret);

 	op_release(new_op);
 	return ret;
 }

 /*
  * Post and wait for the I/O upcall to finish
  */
 ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inode,
 	loff_t *offset, struct iov_iter *iter, size_t total_size,
 	loff_t readahead_size, struct orangefs_write_range *wr,
 	int *index_return, struct file *file)
 {
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct orangefs_khandle *handle = &orangefs_inode->refn.khandle;
 	struct orangefs_kernel_op_s *new_op = NULL;
 	int buffer_index;
 	ssize_t ret;
 	size_t copy_amount;
 	int open_for_read;
 	int open_for_write;

 	new_op = op_alloc(ORANGEFS_VFS_OP_FILE_IO);
 	if (!new_op)
 		return -ENOMEM;

 	/* synchronous I/O */
 	new_op->upcall.req.io.readahead_size = readahead_size;
 	new_op->upcall.req.io.io_type = type;
 	new_op->upcall.req.io.refn = orangefs_inode->refn;

 populate_shared_memory:
 	/* get a shared buffer index */
 	buffer_index = orangefs_bufmap_get();
 	if (buffer_index < 0) {
 		ret = buffer_index;
 		gossip_debug(GOSSIP_FILE_DEBUG,
 			     "%s: orangefs_bufmap_get failure (%zd)\n",
 			     __func__, ret);
 		goto out;
 	}
 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "%s(%pU): GET op %p -> buffer_index %d\n",
 		     __func__,
 		     handle,
 		     new_op,
 		     buffer_index);

 	new_op->uses_shared_memory = 1;
 	new_op->upcall.req.io.buf_index = buffer_index;
 	new_op->upcall.req.io.count = total_size;
 	new_op->upcall.req.io.offset = *offset;
 	if (type == ORANGEFS_IO_WRITE && wr) {
 		new_op->upcall.uid = from_kuid(&init_user_ns, wr->uid);
 		new_op->upcall.gid = from_kgid(&init_user_ns, wr->gid);
 	}
 	/*
 	 * Orangefs has no open, and orangefs checks file permissions
 	 * on each file access. Posix requires that file permissions
 	 * be checked on open and nowhere else. Orangefs-through-the-kernel
 	 * needs to seem posix compliant.
 	 *
 	 * The VFS opens files, even if the filesystem provides no
 	 * method. We can see if a file was successfully opened for
 	 * read and or for write by looking at file->f_mode.
 	 *
 	 * When writes are flowing from the page cache, file is no
 	 * longer available. We can trust the VFS to have checked
 	 * file->f_mode before writing to the page cache.
 	 *
 	 * The mode of a file might change between when it is opened
 	 * and IO commences, or it might be created with an arbitrary mode.
 	 *
 	 * We'll make sure we don't hit EACCES during the IO stage by
 	 * using UID 0. Some of the time we have access without changing
 	 * to UID 0 - how to check?
 	 */
 	if (file) {
 		open_for_write = file->f_mode & FMODE_WRITE;
 		open_for_read = file->f_mode & FMODE_READ;
 	} else {
 		open_for_write = 1;
 		open_for_read = 0; /* not relevant? */
 	}
 	if ((type == ORANGEFS_IO_WRITE) && open_for_write)
 		new_op->upcall.uid = 0;
 	if ((type == ORANGEFS_IO_READ) && open_for_read)
 		new_op->upcall.uid = 0;

 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "%s(%pU): offset: %llu total_size: %zd\n",
 		     __func__,
 		     handle,
 		     llu(*offset),
 		     total_size);
 	/*
 	 * Stage 1: copy the buffers into client-core's address space
 	 */
 	if (type == ORANGEFS_IO_WRITE && total_size) {
 		ret = orangefs_bufmap_copy_from_iovec(iter, buffer_index,
 		    total_size);
 		if (ret < 0) {
 			gossip_err("%s: Failed to copy-in buffers. Please make sure that the pvfs2-client is running. %ld\n",
 			    __func__, (long)ret);
 			goto out;
 		}
 	}

 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "%s(%pU): Calling post_io_request with tag (%llu)\n",
 		     __func__,
 		     handle,
 		     llu(new_op->tag));

 	/* Stage 2: Service the I/O operation */
 	ret = service_operation(new_op,
 				type == ORANGEFS_IO_WRITE ?
 					"file_write" :
 					"file_read",
 				get_interruptible_flag(inode));

 	/*
 	 * If service_operation() returns -EAGAIN #and# the operation was
 	 * purged from orangefs_request_list or htable_ops_in_progress, then
 	 * we know that the client was restarted, causing the shared memory
 	 * area to be wiped clean.  To restart a  write operation in this
 	 * case, we must re-copy the data from the user's iovec to a NEW
 	 * shared memory location. To restart a read operation, we must get
 	 * a new shared memory location.
 	 */
 	if (ret == -EAGAIN && op_state_purged(new_op)) {
 		orangefs_bufmap_put(buffer_index);
 		if (type == ORANGEFS_IO_WRITE)
 			iov_iter_revert(iter, total_size);
 		gossip_debug(GOSSIP_FILE_DEBUG,
 			     "%s:going to repopulate_shared_memory.\n",
 			     __func__);
 		goto populate_shared_memory;
 	}

 	if (ret < 0) {
 		if (ret == -EINTR) {
 			/*
 			 * We can't return EINTR if any data was written,
 			 * it's not POSIX. It is minimally acceptable
 			 * to give a partial write, the way NFS does.
 			 *
 			 * It would be optimal to return all or nothing,
 			 * but if a userspace write is bigger than
 			 * an IO buffer, and the interrupt occurs
 			 * between buffer writes, that would not be
 			 * possible.
 			 */
 			switch (new_op->op_state - OP_VFS_STATE_GIVEN_UP) {
 			/*
 			 * If the op was waiting when the interrupt
 			 * occurred, then the client-core did not
 			 * trigger the write.
 			 */
 			case OP_VFS_STATE_WAITING:
 				if (*offset == 0)
 					ret = -EINTR;
 				else
 					ret = 0;
 				break;
 			/*
 			 * If the op was in progress when the interrupt
 			 * occurred, then the client-core was able to
 			 * trigger the write.
 			 */
 			case OP_VFS_STATE_INPROGR:
 				if (type == ORANGEFS_IO_READ)
 					ret = -EINTR;
 				else
 					ret = total_size;
 				break;
 			default:
 				gossip_err("%s: unexpected op state :%d:.\n",
 					   __func__,
 					   new_op->op_state);
 				ret = 0;
 				break;
 			}
 			gossip_debug(GOSSIP_FILE_DEBUG,
 				     "%s: got EINTR, state:%d: %p\n",
 				     __func__,
 				     new_op->op_state,
 				     new_op);
 		} else {
 			gossip_err("%s: error in %s handle %pU, returning %zd\n",
 				__func__,
 				type == ORANGEFS_IO_READ ?
 					"read from" : "write to",
 				handle, ret);
 		}
 		if (orangefs_cancel_op_in_progress(new_op))
 			return ret;

 		goto out;
 	}

 	/*
 	 * Stage 3: Post copy buffers from client-core's address space
 	 */
 	if (type == ORANGEFS_IO_READ && new_op->downcall.resp.io.amt_complete) {
 		/*
 		 * NOTE: the iovector can either contain addresses which
 		 *       can futher be kernel-space or user-space addresses.
 		 *       or it can pointers to struct page's
 		 */

 		copy_amount = new_op->downcall.resp.io.amt_complete;

 		ret = orangefs_bufmap_copy_to_iovec(iter, buffer_index,
 			copy_amount);
 		if (ret < 0) {
 			gossip_err("%s: Failed to copy-out buffers. Please make sure that the pvfs2-client is running (%ld)\n",
 			    __func__, (long)ret);
 			goto out;
 		}
 	}
 	gossip_debug(GOSSIP_FILE_DEBUG,
 	    "%s(%pU): Amount %s, returned by the sys-io call:%d\n",
 	    __func__,
 	    handle,
 	    type == ORANGEFS_IO_READ ?  "read" : "written",
 	    (int)new_op->downcall.resp.io.amt_complete);

 	ret = new_op->downcall.resp.io.amt_complete;

 out:
 	if (buffer_index >= 0) {
 		orangefs_bufmap_put(buffer_index);
 		gossip_debug(GOSSIP_FILE_DEBUG,
 			"%s(%pU): PUT buffer_index %d\n",
 			__func__, handle, buffer_index);
 	}
 	op_release(new_op);
 	return ret;
 }

 int orangefs_revalidate_mapping(struct inode *inode)
 {
 	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 	struct address_space *mapping = inode->i_mapping;
 	unsigned long *bitlock = &orangefs_inode->bitlock;
 	int ret;

 	while (1) {
 		ret = wait_on_bit(bitlock, 1, TASK_KILLABLE);
 		if (ret)
 			return ret;
 		spin_lock(&inode->i_lock);
 		if (test_bit(1, bitlock)) {
 			spin_unlock(&inode->i_lock);
 			continue;
 		}
 		if (!time_before(jiffies, orangefs_inode->mapping_time))
 			break;
 		spin_unlock(&inode->i_lock);
 		return 0;
 	}

 	set_bit(1, bitlock);
 	smp_wmb();
 	spin_unlock(&inode->i_lock);

 	unmap_mapping_range(mapping, 0, 0, 0);
 	ret = filemap_write_and_wait(mapping);
 	if (!ret)
 		ret = invalidate_inode_pages2(mapping);

 	orangefs_inode->mapping_time = jiffies +
 	    orangefs_cache_timeout_msecs*HZ/1000;

 	clear_bit(1, bitlock);
 	smp_mb__after_atomic();
 	wake_up_bit(bitlock, 1);

 	return ret;
 }

 static ssize_t orangefs_file_read_iter(struct kiocb *iocb,
     struct iov_iter *iter)
 {
 	int ret;
 	orangefs_stats.reads++;

 	down_read(&file_inode(iocb->ki_filp)->i_rwsem);
 	ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
 	if (ret)
 		goto out;

 	ret = generic_file_read_iter(iocb, iter);
 out:
 	up_read(&file_inode(iocb->ki_filp)->i_rwsem);
 	return ret;
 }

 static ssize_t orangefs_file_splice_read(struct file *in, loff_t *ppos,
 					 struct pipe_inode_info *pipe,
 					 size_t len, unsigned int flags)
 {
 	struct inode *inode = file_inode(in);
 	ssize_t ret;

 	orangefs_stats.reads++;

 	down_read(&inode->i_rwsem);
 	ret = orangefs_revalidate_mapping(inode);
 	if (ret)
 		goto out;

 	ret = filemap_splice_read(in, ppos, pipe, len, flags);
 out:
 	up_read(&inode->i_rwsem);
 	return ret;
 }

 static ssize_t orangefs_file_write_iter(struct kiocb *iocb,
     struct iov_iter *iter)
 {
 	int ret;
 	orangefs_stats.writes++;

 	if (iocb->ki_pos > i_size_read(file_inode(iocb->ki_filp))) {
 		ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
 		if (ret)
 			return ret;
 	}

 	ret = generic_file_write_iter(iocb, iter);
 	return ret;
 }

 static vm_fault_t orangefs_fault(struct vm_fault *vmf)
 {
 	struct file *file = vmf->vma->vm_file;
 	int ret;
 	ret = orangefs_inode_getattr(file->f_mapping->host,
 	    ORANGEFS_GETATTR_SIZE);
 	if (ret == -ESTALE)
 		ret = -EIO;
 	if (ret) {
 		gossip_err("%s: orangefs_inode_getattr failed, "
 		    "ret:%d:.\n", __func__, ret);
 		return VM_FAULT_SIGBUS;
 	}
 	return filemap_fault(vmf);
 }

 static const struct vm_operations_struct orangefs_file_vm_ops = {
 	.fault = orangefs_fault,
 	.map_pages = filemap_map_pages,
 	.page_mkwrite = orangefs_page_mkwrite,
 };

 /*
  * Memory map a region of a file.
  */
 static int orangefs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	int ret;

 	ret = orangefs_revalidate_mapping(file_inode(file));
 	if (ret)
 		return ret;

 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "orangefs_file_mmap: called on %pD\n", file);

 	/* set the sequential readahead hint */
 	vm_flags_mod(vma, VM_SEQ_READ, VM_RAND_READ);

 	file_accessed(file);
 	vma->vm_ops = &orangefs_file_vm_ops;
 	return 0;
 }

 #define mapping_nrpages(idata) ((idata)->nrpages)

 /*
  * Called to notify the module that there are no more references to
  * this file (i.e. no processes have it open).
  *
  * \note Not called when each file is closed.
  */
 static int orangefs_file_release(struct inode *inode, struct file *file)
 {
 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "orangefs_file_release: called on %pD\n",
 		     file);

 	/*
 	 * remove all associated inode pages from the page cache and
 	 * readahead cache (if any); this forces an expensive refresh of
 	 * data for the next caller of mmap (or 'get_block' accesses)
 	 */
 	if (mapping_nrpages(file->f_mapping)) {
 		if (orangefs_features & ORANGEFS_FEATURE_READAHEAD) {
 			gossip_debug(GOSSIP_INODE_DEBUG,
 			    "calling flush_racache on %pU\n",
 			    get_khandle_from_ino(inode));
 			flush_racache(inode);
 			gossip_debug(GOSSIP_INODE_DEBUG,
 			    "flush_racache finished\n");
 		}

 	}
 	return 0;
 }

 /*
  * Push all data for a specific file onto permanent storage.
  */
 static int orangefs_fsync(struct file *file,
 		       loff_t start,
 		       loff_t end,
 		       int datasync)
 {
 	int ret;
 	struct orangefs_inode_s *orangefs_inode =
 		ORANGEFS_I(file_inode(file));
 	struct orangefs_kernel_op_s *new_op = NULL;

 	ret = filemap_write_and_wait_range(file_inode(file)->i_mapping,
 	    start, end);
 	if (ret < 0)
 		return ret;

 	new_op = op_alloc(ORANGEFS_VFS_OP_FSYNC);
 	if (!new_op)
 		return -ENOMEM;
 	new_op->upcall.req.fsync.refn = orangefs_inode->refn;

 	ret = service_operation(new_op,
 			"orangefs_fsync",
 			get_interruptible_flag(file_inode(file)));

 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "orangefs_fsync got return value of %d\n",
 		     ret);

 	op_release(new_op);
 	return ret;
 }

 /*
  * Change the file pointer position for an instance of an open file.
  *
  * \note If .llseek is overriden, we must acquire lock as described in
  *       Documentation/filesystems/locking.rst.
  *
  * Future upgrade could support SEEK_DATA and SEEK_HOLE but would
  * require much changes to the FS
  */
 static loff_t orangefs_file_llseek(struct file *file, loff_t offset, int origin)
 {
 	int ret = -EINVAL;
 	struct inode *inode = file_inode(file);

 	if (origin == SEEK_END) {
 		/*
 		 * revalidate the inode's file size.
 		 * NOTE: We are only interested in file size here,
 		 * so we set mask accordingly.
 		 */
 		ret = orangefs_inode_getattr(file->f_mapping->host,
 		    ORANGEFS_GETATTR_SIZE);
 		if (ret == -ESTALE)
 			ret = -EIO;
 		if (ret) {
 			gossip_debug(GOSSIP_FILE_DEBUG,
 				     "%s:%s:%d calling make bad inode\n",
 				     __FILE__,
 				     __func__,
 				     __LINE__);
 			return ret;
 		}
 	}

 	gossip_debug(GOSSIP_FILE_DEBUG,
 		     "orangefs_file_llseek: offset is %ld | origin is %d"
 		     " | inode size is %lu\n",
 		     (long)offset,
 		     origin,
 		     (unsigned long)i_size_read(inode));

 	return generic_file_llseek(file, offset, origin);
 }

 /*
  * Support local locks (locks that only this kernel knows about)
  * if Orangefs was mounted -o local_lock.
  */
 static int orangefs_lock(struct file *filp, int cmd, struct file_lock *fl)
 {
 	int rc = -EINVAL;

 	if (ORANGEFS_SB(file_inode(filp)->i_sb)->flags & ORANGEFS_OPT_LOCAL_LOCK) {
 		if (cmd == F_GETLK) {
 			rc = 0;
 			posix_test_lock(filp, fl);
 		} else {
 			rc = posix_lock_file(filp, fl, NULL);
 		}
 	}

 	return rc;
 }

 static int orangefs_flush(struct file *file, fl_owner_t id)
 {
 	/*
 	 * This is vfs_fsync_range(file, 0, LLONG_MAX, 0) without the
 	 * service_operation in orangefs_fsync.
 	 *
 	 * Do not send fsync to OrangeFS server on a close.  Do send fsync
 	 * on an explicit fsync call.  This duplicates historical OrangeFS
 	 * behavior.
 	 */
 	int r;

 	r = filemap_write_and_wait_range(file->f_mapping, 0, LLONG_MAX);
 	if (r > 0)
 		return 0;
 	else
 		return r;
 }

 /** ORANGEFS implementation of VFS file operations */
 const struct file_operations orangefs_file_operations = {
 	.llseek		= orangefs_file_llseek,
 	.read_iter	= orangefs_file_read_iter,
 	.write_iter	= orangefs_file_write_iter,
 	.lock		= orangefs_lock,
 	.mmap		= orangefs_file_mmap,
 	.open		= generic_file_open,
 	.splice_read    = orangefs_file_splice_read,
 	.splice_write   = iter_file_splice_write,
 	.flush		= orangefs_flush,
 	.release	= orangefs_file_release,
 	.fsync		= orangefs_fsync,
 };
	// SPDX-License-Identifier: GPL-2.0
	/*
	* (C) 2001 Clemson University and The University of Chicago
	* Copyright 2018 Omnibond Systems, L.L.C.
	*
	* See COPYING in top-level directory.
	*/

	/*
	* Linux VFS file operations.
	*/

	#include "protocol.h"
	#include "orangefs-kernel.h"
	#include "orangefs-bufmap.h"
	#include <linux/fs.h>
	#include <linux/filelock.h>
	#include <linux/pagemap.h>

	static int flush_racache(struct inode *inode)
	{
	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
	struct orangefs_kernel_op_s *new_op;
	int ret;

	gossip_debug(GOSSIP_UTILS_DEBUG,
	"%s: %pU: Handle is %pU \| fs_id %d\n", __func__,
	get_khandle_from_ino(inode), &orangefs_inode->refn.khandle,
	orangefs_inode->refn.fs_id);

	new_op = op_alloc(ORANGEFS_VFS_OP_RA_FLUSH);
	if (!new_op)
	return -ENOMEM;
	new_op->upcall.req.ra_cache_flush.refn = orangefs_inode->refn;

	ret = service_operation(new_op, "orangefs_flush_racache",
	get_interruptible_flag(inode));

	gossip_debug(GOSSIP_UTILS_DEBUG, "%s: got return value of %d\n",
	__func__, ret);

	op_release(new_op);
	return ret;
	}

	/*
	* Post and wait for the I/O upcall to finish
	*/
	ssize_t wait_for_direct_io(enum ORANGEFS_io_type type, struct inode *inode,
	loff_t offset, struct iov_iter iter, size_t total_size,
	loff_t readahead_size, struct orangefs_write_range *wr,
	int index_return, struct file file)
	{
	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
	struct orangefs_khandle *handle = &orangefs_inode->refn.khandle;
	struct orangefs_kernel_op_s *new_op = NULL;
	int buffer_index;
	ssize_t ret;
	size_t copy_amount;
	int open_for_read;
	int open_for_write;

	new_op = op_alloc(ORANGEFS_VFS_OP_FILE_IO);
	if (!new_op)
	return -ENOMEM;

	/* synchronous I/O */
	new_op->upcall.req.io.readahead_size = readahead_size;
	new_op->upcall.req.io.io_type = type;
	new_op->upcall.req.io.refn = orangefs_inode->refn;

	populate_shared_memory:
	/* get a shared buffer index */
	buffer_index = orangefs_bufmap_get();
	if (buffer_index < 0) {
	ret = buffer_index;
	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s: orangefs_bufmap_get failure (%zd)\n",
	__func__, ret);
	goto out;
	}
	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s(%pU): GET op %p -> buffer_index %d\n",
	__func__,
	handle,
	new_op,
	buffer_index);

	new_op->uses_shared_memory = 1;
	new_op->upcall.req.io.buf_index = buffer_index;
	new_op->upcall.req.io.count = total_size;
	new_op->upcall.req.io.offset = *offset;
	if (type == ORANGEFS_IO_WRITE && wr) {
	new_op->upcall.uid = from_kuid(&init_user_ns, wr->uid);
	new_op->upcall.gid = from_kgid(&init_user_ns, wr->gid);
	}
	/*
	* Orangefs has no open, and orangefs checks file permissions
	* on each file access. Posix requires that file permissions
	* be checked on open and nowhere else. Orangefs-through-the-kernel
	* needs to seem posix compliant.
	*
	* The VFS opens files, even if the filesystem provides no
	* method. We can see if a file was successfully opened for
	* read and or for write by looking at file->f_mode.
	*
	* When writes are flowing from the page cache, file is no
	* longer available. We can trust the VFS to have checked
	* file->f_mode before writing to the page cache.
	*
	* The mode of a file might change between when it is opened
	* and IO commences, or it might be created with an arbitrary mode.
	*
	* We'll make sure we don't hit EACCES during the IO stage by
	* using UID 0. Some of the time we have access without changing
	* to UID 0 - how to check?
	*/
	if (file) {
	open_for_write = file->f_mode & FMODE_WRITE;
	open_for_read = file->f_mode & FMODE_READ;
	} else {
	open_for_write = 1;
	open_for_read = 0; /* not relevant? */
	}
	if ((type == ORANGEFS_IO_WRITE) && open_for_write)
	new_op->upcall.uid = 0;
	if ((type == ORANGEFS_IO_READ) && open_for_read)
	new_op->upcall.uid = 0;

	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s(%pU): offset: %llu total_size: %zd\n",
	__func__,
	handle,
	llu(*offset),
	total_size);
	/*
	* Stage 1: copy the buffers into client-core's address space
	*/
	if (type == ORANGEFS_IO_WRITE && total_size) {
	ret = orangefs_bufmap_copy_from_iovec(iter, buffer_index,
	total_size);
	if (ret < 0) {
	gossip_err("%s: Failed to copy-in buffers. Please make sure that the pvfs2-client is running. %ld\n",
	__func__, (long)ret);
	goto out;
	}
	}

	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s(%pU): Calling post_io_request with tag (%llu)\n",
	__func__,
	handle,
	llu(new_op->tag));

	/* Stage 2: Service the I/O operation */
	ret = service_operation(new_op,
	type == ORANGEFS_IO_WRITE ?
	"file_write" :
	"file_read",
	get_interruptible_flag(inode));

	/*
	* If service_operation() returns -EAGAIN #and# the operation was
	* purged from orangefs_request_list or htable_ops_in_progress, then
	* we know that the client was restarted, causing the shared memory
	* area to be wiped clean. To restart a write operation in this
	* case, we must re-copy the data from the user's iovec to a NEW
	* shared memory location. To restart a read operation, we must get
	* a new shared memory location.
	*/
	if (ret == -EAGAIN && op_state_purged(new_op)) {
	orangefs_bufmap_put(buffer_index);
	if (type == ORANGEFS_IO_WRITE)
	iov_iter_revert(iter, total_size);
	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s:going to repopulate_shared_memory.\n",
	__func__);
	goto populate_shared_memory;
	}

	if (ret < 0) {
	if (ret == -EINTR) {
	/*
	* We can't return EINTR if any data was written,
	* it's not POSIX. It is minimally acceptable
	* to give a partial write, the way NFS does.
	*
	* It would be optimal to return all or nothing,
	* but if a userspace write is bigger than
	* an IO buffer, and the interrupt occurs
	* between buffer writes, that would not be
	* possible.
	*/
	switch (new_op->op_state - OP_VFS_STATE_GIVEN_UP) {
	/*
	* If the op was waiting when the interrupt
	* occurred, then the client-core did not
	* trigger the write.
	*/
	case OP_VFS_STATE_WAITING:
	if (*offset == 0)
	ret = -EINTR;
	else
	ret = 0;
	break;
	/*
	* If the op was in progress when the interrupt
	* occurred, then the client-core was able to
	* trigger the write.
	*/
	case OP_VFS_STATE_INPROGR:
	if (type == ORANGEFS_IO_READ)
	ret = -EINTR;
	else
	ret = total_size;
	break;
	default:
	gossip_err("%s: unexpected op state :%d:.\n",
	__func__,
	new_op->op_state);
	ret = 0;
	break;
	}
	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s: got EINTR, state:%d: %p\n",
	__func__,
	new_op->op_state,
	new_op);
	} else {
	gossip_err("%s: error in %s handle %pU, returning %zd\n",
	__func__,
	type == ORANGEFS_IO_READ ?
	"read from" : "write to",
	handle, ret);
	}
	if (orangefs_cancel_op_in_progress(new_op))
	return ret;

	goto out;
	}

	/*
	* Stage 3: Post copy buffers from client-core's address space
	*/
	if (type == ORANGEFS_IO_READ && new_op->downcall.resp.io.amt_complete) {
	/*
	* NOTE: the iovector can either contain addresses which
	* can futher be kernel-space or user-space addresses.
	* or it can pointers to struct page's
	*/

	copy_amount = new_op->downcall.resp.io.amt_complete;

	ret = orangefs_bufmap_copy_to_iovec(iter, buffer_index,
	copy_amount);
	if (ret < 0) {
	gossip_err("%s: Failed to copy-out buffers. Please make sure that the pvfs2-client is running (%ld)\n",
	__func__, (long)ret);
	goto out;
	}
	}
	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s(%pU): Amount %s, returned by the sys-io call:%d\n",
	__func__,
	handle,
	type == ORANGEFS_IO_READ ? "read" : "written",
	(int)new_op->downcall.resp.io.amt_complete);

	ret = new_op->downcall.resp.io.amt_complete;

	out:
	if (buffer_index >= 0) {
	orangefs_bufmap_put(buffer_index);
	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s(%pU): PUT buffer_index %d\n",
	__func__, handle, buffer_index);
	}
	op_release(new_op);
	return ret;
	}

	int orangefs_revalidate_mapping(struct inode *inode)
	{
	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
	struct address_space *mapping = inode->i_mapping;
	unsigned long *bitlock = &orangefs_inode->bitlock;
	int ret;

	while (1) {
	ret = wait_on_bit(bitlock, 1, TASK_KILLABLE);
	if (ret)
	return ret;
	spin_lock(&inode->i_lock);
	if (test_bit(1, bitlock)) {
	spin_unlock(&inode->i_lock);
	continue;
	}
	if (!time_before(jiffies, orangefs_inode->mapping_time))
	break;
	spin_unlock(&inode->i_lock);
	return 0;
	}

	set_bit(1, bitlock);
	smp_wmb();
	spin_unlock(&inode->i_lock);

	unmap_mapping_range(mapping, 0, 0, 0);
	ret = filemap_write_and_wait(mapping);
	if (!ret)
	ret = invalidate_inode_pages2(mapping);

	orangefs_inode->mapping_time = jiffies +
	orangefs_cache_timeout_msecs*HZ/1000;

	clear_bit(1, bitlock);
	smp_mb__after_atomic();
	wake_up_bit(bitlock, 1);

	return ret;
	}

	static ssize_t orangefs_file_read_iter(struct kiocb *iocb,
	struct iov_iter *iter)
	{
	int ret;
	orangefs_stats.reads++;

	down_read(&file_inode(iocb->ki_filp)->i_rwsem);
	ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
	if (ret)
	goto out;

	ret = generic_file_read_iter(iocb, iter);
	out:
	up_read(&file_inode(iocb->ki_filp)->i_rwsem);
	return ret;
	}

	static ssize_t orangefs_file_splice_read(struct file in, loff_t ppos,
	struct pipe_inode_info *pipe,
	size_t len, unsigned int flags)
	{
	struct inode *inode = file_inode(in);
	ssize_t ret;

	orangefs_stats.reads++;

	down_read(&inode->i_rwsem);
	ret = orangefs_revalidate_mapping(inode);
	if (ret)
	goto out;

	ret = filemap_splice_read(in, ppos, pipe, len, flags);
	out:
	up_read(&inode->i_rwsem);
	return ret;
	}

	static ssize_t orangefs_file_write_iter(struct kiocb *iocb,
	struct iov_iter *iter)
	{
	int ret;
	orangefs_stats.writes++;

	if (iocb->ki_pos > i_size_read(file_inode(iocb->ki_filp))) {
	ret = orangefs_revalidate_mapping(file_inode(iocb->ki_filp));
	if (ret)
	return ret;
	}

	ret = generic_file_write_iter(iocb, iter);
	return ret;
	}

	static vm_fault_t orangefs_fault(struct vm_fault *vmf)
	{
	struct file *file = vmf->vma->vm_file;
	int ret;
	ret = orangefs_inode_getattr(file->f_mapping->host,
	ORANGEFS_GETATTR_SIZE);
	if (ret == -ESTALE)
	ret = -EIO;
	if (ret) {
	gossip_err("%s: orangefs_inode_getattr failed, "
	"ret:%d:.\n", __func__, ret);
	return VM_FAULT_SIGBUS;
	}
	return filemap_fault(vmf);
	}

	static const struct vm_operations_struct orangefs_file_vm_ops = {
	.fault = orangefs_fault,
	.map_pages = filemap_map_pages,
	.page_mkwrite = orangefs_page_mkwrite,
	};

	/*
	* Memory map a region of a file.
	*/
	static int orangefs_file_mmap(struct file file, struct vm_area_struct vma)
	{
	int ret;

	ret = orangefs_revalidate_mapping(file_inode(file));
	if (ret)
	return ret;

	gossip_debug(GOSSIP_FILE_DEBUG,
	"orangefs_file_mmap: called on %pD\n", file);

	/* set the sequential readahead hint */
	vm_flags_mod(vma, VM_SEQ_READ, VM_RAND_READ);

	file_accessed(file);
	vma->vm_ops = &orangefs_file_vm_ops;
	return 0;
	}

	#define mapping_nrpages(idata) ((idata)->nrpages)

	/*
	* Called to notify the module that there are no more references to
	* this file (i.e. no processes have it open).
	*
	* \note Not called when each file is closed.
	*/
	static int orangefs_file_release(struct inode inode, struct file file)
	{
	gossip_debug(GOSSIP_FILE_DEBUG,
	"orangefs_file_release: called on %pD\n",
	file);

	/*
	* remove all associated inode pages from the page cache and
	* readahead cache (if any); this forces an expensive refresh of
	* data for the next caller of mmap (or 'get_block' accesses)
	*/
	if (mapping_nrpages(file->f_mapping)) {
	if (orangefs_features & ORANGEFS_FEATURE_READAHEAD) {
	gossip_debug(GOSSIP_INODE_DEBUG,
	"calling flush_racache on %pU\n",
	get_khandle_from_ino(inode));
	flush_racache(inode);
	gossip_debug(GOSSIP_INODE_DEBUG,
	"flush_racache finished\n");
	}

	}
	return 0;
	}

	/*
	* Push all data for a specific file onto permanent storage.
	*/
	static int orangefs_fsync(struct file *file,
	loff_t start,
	loff_t end,
	int datasync)
	{
	int ret;
	struct orangefs_inode_s *orangefs_inode =
	ORANGEFS_I(file_inode(file));
	struct orangefs_kernel_op_s *new_op = NULL;

	ret = filemap_write_and_wait_range(file_inode(file)->i_mapping,
	start, end);
	if (ret < 0)
	return ret;

	new_op = op_alloc(ORANGEFS_VFS_OP_FSYNC);
	if (!new_op)
	return -ENOMEM;
	new_op->upcall.req.fsync.refn = orangefs_inode->refn;

	ret = service_operation(new_op,
	"orangefs_fsync",
	get_interruptible_flag(file_inode(file)));

	gossip_debug(GOSSIP_FILE_DEBUG,
	"orangefs_fsync got return value of %d\n",
	ret);

	op_release(new_op);
	return ret;
	}

	/*
	* Change the file pointer position for an instance of an open file.
	*
	* \note If .llseek is overriden, we must acquire lock as described in
	* Documentation/filesystems/locking.rst.
	*
	* Future upgrade could support SEEK_DATA and SEEK_HOLE but would
	* require much changes to the FS
	*/
	static loff_t orangefs_file_llseek(struct file *file, loff_t offset, int origin)
	{
	int ret = -EINVAL;
	struct inode *inode = file_inode(file);

	if (origin == SEEK_END) {
	/*
	* revalidate the inode's file size.
	* NOTE: We are only interested in file size here,
	* so we set mask accordingly.
	*/
	ret = orangefs_inode_getattr(file->f_mapping->host,
	ORANGEFS_GETATTR_SIZE);
	if (ret == -ESTALE)
	ret = -EIO;
	if (ret) {
	gossip_debug(GOSSIP_FILE_DEBUG,
	"%s:%s:%d calling make bad inode\n",
	__FILE__,
	__func__,
	__LINE__);
	return ret;
	}
	}

	gossip_debug(GOSSIP_FILE_DEBUG,
	"orangefs_file_llseek: offset is %ld \| origin is %d"
	" \| inode size is %lu\n",
	(long)offset,
	origin,
	(unsigned long)i_size_read(inode));

	return generic_file_llseek(file, offset, origin);
	}

	/*
	* Support local locks (locks that only this kernel knows about)
	* if Orangefs was mounted -o local_lock.
	*/
	static int orangefs_lock(struct file filp, int cmd, struct file_lock fl)
	{
	int rc = -EINVAL;

	if (ORANGEFS_SB(file_inode(filp)->i_sb)->flags & ORANGEFS_OPT_LOCAL_LOCK) {
	if (cmd == F_GETLK) {
	rc = 0;
	posix_test_lock(filp, fl);
	} else {
	rc = posix_lock_file(filp, fl, NULL);
	}
	}

	return rc;
	}

	static int orangefs_flush(struct file *file, fl_owner_t id)
	{
	/*
	* This is vfs_fsync_range(file, 0, LLONG_MAX, 0) without the
	* service_operation in orangefs_fsync.
	*
	* Do not send fsync to OrangeFS server on a close. Do send fsync
	* on an explicit fsync call. This duplicates historical OrangeFS
	* behavior.
	*/
	int r;

	r = filemap_write_and_wait_range(file->f_mapping, 0, LLONG_MAX);
	if (r > 0)
	return 0;
	else
	return r;
	}

	/** ORANGEFS implementation of VFS file operations */
	const struct file_operations orangefs_file_operations = {
	.llseek = orangefs_file_llseek,
	.read_iter = orangefs_file_read_iter,
	.write_iter = orangefs_file_write_iter,
	.lock = orangefs_lock,
	.mmap = orangefs_file_mmap,
	.open = generic_file_open,
	.splice_read = orangefs_file_splice_read,
	.splice_write = iter_file_splice_write,
	.flush = orangefs_flush,
	.release = orangefs_file_release,
	.fsync = orangefs_fsync,
	};