Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 5298 insertions, 0 deletions

diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
new file mode 100644
index 000000000..0f3405e0f
--- /dev/null
+++ b/fs/smb/client/file.c
@@ -0,0 +1,5298 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ *
+ *   vfs operations that deal with files
+ *
+ *   Copyright (C) International Business Machines  Corp., 2002,2010
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *              Jeremy Allison (jra@samba.org)
+ *
+ */
+#include <linux/fs.h>
+#include <linux/backing-dev.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <linux/pagemap.h>
+#include <linux/pagevec.h>
+#include <linux/writeback.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/delay.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/mm.h>
+#include <asm/div64.h>
+#include "cifsfs.h"
+#include "cifspdu.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "smb2proto.h"
+#include "cifs_unicode.h"
+#include "cifs_debug.h"
+#include "cifs_fs_sb.h"
+#include "fscache.h"
+#include "smbdirect.h"
+#include "fs_context.h"
+#include "cifs_ioctl.h"
+#include "cached_dir.h"
+
+/*
+ * Mark as invalid, all open files on tree connections since they
+ * were closed when session to server was lost.
+ */
+void
+cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
+{
+	struct cifsFileInfo *open_file = NULL;
+	struct list_head *tmp;
+	struct list_head *tmp1;
+
+	/* only send once per connect */
+	spin_lock(&tcon->ses->ses_lock);
+	if ((tcon->ses->ses_status != SES_GOOD) || (tcon->status != TID_NEED_RECON)) {
+		spin_unlock(&tcon->ses->ses_lock);
+		return;
+	}
+	tcon->status = TID_IN_FILES_INVALIDATE;
+	spin_unlock(&tcon->ses->ses_lock);
+
+	/* list all files open on tree connection and mark them invalid */
+	spin_lock(&tcon->open_file_lock);
+	list_for_each_safe(tmp, tmp1, &tcon->openFileList) {
+		open_file = list_entry(tmp, struct cifsFileInfo, tlist);
+		open_file->invalidHandle = true;
+		open_file->oplock_break_cancelled = true;
+	}
+	spin_unlock(&tcon->open_file_lock);
+
+	invalidate_all_cached_dirs(tcon);
+	spin_lock(&tcon->tc_lock);
+	if (tcon->status == TID_IN_FILES_INVALIDATE)
+		tcon->status = TID_NEED_TCON;
+	spin_unlock(&tcon->tc_lock);
+
+	/*
+	 * BB Add call to invalidate_inodes(sb) for all superblocks mounted
+	 * to this tcon.
+	 */
+}
+
+static inline int cifs_convert_flags(unsigned int flags)
+{
+	if ((flags & O_ACCMODE) == O_RDONLY)
+		return GENERIC_READ;
+	else if ((flags & O_ACCMODE) == O_WRONLY)
+		return GENERIC_WRITE;
+	else if ((flags & O_ACCMODE) == O_RDWR) {
+		/* GENERIC_ALL is too much permission to request
+		   can cause unnecessary access denied on create */
+		/* return GENERIC_ALL; */
+		return (GENERIC_READ | GENERIC_WRITE);
+	}
+
+	return (READ_CONTROL | FILE_WRITE_ATTRIBUTES | FILE_READ_ATTRIBUTES |
+		FILE_WRITE_EA | FILE_APPEND_DATA | FILE_WRITE_DATA |
+		FILE_READ_DATA);
+}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+static u32 cifs_posix_convert_flags(unsigned int flags)
+{
+	u32 posix_flags = 0;
+
+	if ((flags & O_ACCMODE) == O_RDONLY)
+		posix_flags = SMB_O_RDONLY;
+	else if ((flags & O_ACCMODE) == O_WRONLY)
+		posix_flags = SMB_O_WRONLY;
+	else if ((flags & O_ACCMODE) == O_RDWR)
+		posix_flags = SMB_O_RDWR;
+
+	if (flags & O_CREAT) {
+		posix_flags |= SMB_O_CREAT;
+		if (flags & O_EXCL)
+			posix_flags |= SMB_O_EXCL;
+	} else if (flags & O_EXCL)
+		cifs_dbg(FYI, "Application %s pid %d has incorrectly set O_EXCL flag but not O_CREAT on file open. Ignoring O_EXCL\n",
+			 current->comm, current->tgid);
+
+	if (flags & O_TRUNC)
+		posix_flags |= SMB_O_TRUNC;
+	/* be safe and imply O_SYNC for O_DSYNC */
+	if (flags & O_DSYNC)
+		posix_flags |= SMB_O_SYNC;
+	if (flags & O_DIRECTORY)
+		posix_flags |= SMB_O_DIRECTORY;
+	if (flags & O_NOFOLLOW)
+		posix_flags |= SMB_O_NOFOLLOW;
+	if (flags & O_DIRECT)
+		posix_flags |= SMB_O_DIRECT;
+
+	return posix_flags;
+}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+static inline int cifs_get_disposition(unsigned int flags)
+{
+	if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
+		return FILE_CREATE;
+	else if ((flags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
+		return FILE_OVERWRITE_IF;
+	else if ((flags & O_CREAT) == O_CREAT)
+		return FILE_OPEN_IF;
+	else if ((flags & O_TRUNC) == O_TRUNC)
+		return FILE_OVERWRITE;
+	else
+		return FILE_OPEN;
+}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+int cifs_posix_open(const char *full_path, struct inode **pinode,
+			struct super_block *sb, int mode, unsigned int f_flags,
+			__u32 *poplock, __u16 *pnetfid, unsigned int xid)
+{
+	int rc;
+	FILE_UNIX_BASIC_INFO *presp_data;
+	__u32 posix_flags = 0;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+	struct cifs_fattr fattr;
+	struct tcon_link *tlink;
+	struct cifs_tcon *tcon;
+
+	cifs_dbg(FYI, "posix open %s\n", full_path);
+
+	presp_data = kzalloc(sizeof(FILE_UNIX_BASIC_INFO), GFP_KERNEL);
+	if (presp_data == NULL)
+		return -ENOMEM;
+
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		rc = PTR_ERR(tlink);
+		goto posix_open_ret;
+	}
+
+	tcon = tlink_tcon(tlink);
+	mode &= ~current_umask();
+
+	posix_flags = cifs_posix_convert_flags(f_flags);
+	rc = CIFSPOSIXCreate(xid, tcon, posix_flags, mode, pnetfid, presp_data,
+			     poplock, full_path, cifs_sb->local_nls,
+			     cifs_remap(cifs_sb));
+	cifs_put_tlink(tlink);
+
+	if (rc)
+		goto posix_open_ret;
+
+	if (presp_data->Type == cpu_to_le32(-1))
+		goto posix_open_ret; /* open ok, caller does qpathinfo */
+
+	if (!pinode)
+		goto posix_open_ret; /* caller does not need info */
+
+	cifs_unix_basic_to_fattr(&fattr, presp_data, cifs_sb);
+
+	/* get new inode and set it up */
+	if (*pinode == NULL) {
+		cifs_fill_uniqueid(sb, &fattr);
+		*pinode = cifs_iget(sb, &fattr);
+		if (!*pinode) {
+			rc = -ENOMEM;
+			goto posix_open_ret;
+		}
+	} else {
+		cifs_revalidate_mapping(*pinode);
+		rc = cifs_fattr_to_inode(*pinode, &fattr);
+	}
+
+posix_open_ret:
+	kfree(presp_data);
+	return rc;
+}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+static int cifs_nt_open(const char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
+			struct cifs_tcon *tcon, unsigned int f_flags, __u32 *oplock,
+			struct cifs_fid *fid, unsigned int xid, struct cifs_open_info_data *buf)
+{
+	int rc;
+	int desired_access;
+	int disposition;
+	int create_options = CREATE_NOT_DIR;
+	struct TCP_Server_Info *server = tcon->ses->server;
+	struct cifs_open_parms oparms;
+
+	if (!server->ops->open)
+		return -ENOSYS;
+
+	desired_access = cifs_convert_flags(f_flags);
+
+/*********************************************************************
+ *  open flag mapping table:
+ *
+ *	POSIX Flag            CIFS Disposition
+ *	----------            ----------------
+ *	O_CREAT               FILE_OPEN_IF
+ *	O_CREAT | O_EXCL      FILE_CREATE
+ *	O_CREAT | O_TRUNC     FILE_OVERWRITE_IF
+ *	O_TRUNC               FILE_OVERWRITE
+ *	none of the above     FILE_OPEN
+ *
+ *	Note that there is not a direct match between disposition
+ *	FILE_SUPERSEDE (ie create whether or not file exists although
+ *	O_CREAT | O_TRUNC is similar but truncates the existing
+ *	file rather than creating a new file as FILE_SUPERSEDE does
+ *	(which uses the attributes / metadata passed in on open call)
+ *?
+ *?  O_SYNC is a reasonable match to CIFS writethrough flag
+ *?  and the read write flags match reasonably.  O_LARGEFILE
+ *?  is irrelevant because largefile support is always used
+ *?  by this client. Flags O_APPEND, O_DIRECT, O_DIRECTORY,
+ *	 O_FASYNC, O_NOFOLLOW, O_NONBLOCK need further investigation
+ *********************************************************************/
+
+	disposition = cifs_get_disposition(f_flags);
+
+	/* BB pass O_SYNC flag through on file attributes .. BB */
+
+	/* O_SYNC also has bit for O_DSYNC so following check picks up either */
+	if (f_flags & O_SYNC)
+		create_options |= CREATE_WRITE_THROUGH;
+
+	if (f_flags & O_DIRECT)
+		create_options |= CREATE_NO_BUFFER;
+
+	oparms = (struct cifs_open_parms) {
+		.tcon = tcon,
+		.cifs_sb = cifs_sb,
+		.desired_access = desired_access,
+		.create_options = cifs_create_options(cifs_sb, create_options),
+		.disposition = disposition,
+		.path = full_path,
+		.fid = fid,
+	};
+
+	rc = server->ops->open(xid, &oparms, oplock, buf);
+	if (rc)
+		return rc;
+
+	/* TODO: Add support for calling posix query info but with passing in fid */
+	if (tcon->unix_ext)
+		rc = cifs_get_inode_info_unix(&inode, full_path, inode->i_sb,
+					      xid);
+	else
+		rc = cifs_get_inode_info(&inode, full_path, buf, inode->i_sb,
+					 xid, fid);
+
+	if (rc) {
+		server->ops->close(xid, tcon, fid);
+		if (rc == -ESTALE)
+			rc = -EOPENSTALE;
+	}
+
+	return rc;
+}
+
+static bool
+cifs_has_mand_locks(struct cifsInodeInfo *cinode)
+{
+	struct cifs_fid_locks *cur;
+	bool has_locks = false;
+
+	down_read(&cinode->lock_sem);
+	list_for_each_entry(cur, &cinode->llist, llist) {
+		if (!list_empty(&cur->locks)) {
+			has_locks = true;
+			break;
+		}
+	}
+	up_read(&cinode->lock_sem);
+	return has_locks;
+}
+
+void
+cifs_down_write(struct rw_semaphore *sem)
+{
+	while (!down_write_trylock(sem))
+		msleep(10);
+}
+
+static void cifsFileInfo_put_work(struct work_struct *work);
+
+struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
+				       struct tcon_link *tlink, __u32 oplock,
+				       const char *symlink_target)
+{
+	struct dentry *dentry = file_dentry(file);
+	struct inode *inode = d_inode(dentry);
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct cifsFileInfo *cfile;
+	struct cifs_fid_locks *fdlocks;
+	struct cifs_tcon *tcon = tlink_tcon(tlink);
+	struct TCP_Server_Info *server = tcon->ses->server;
+
+	cfile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
+	if (cfile == NULL)
+		return cfile;
+
+	fdlocks = kzalloc(sizeof(struct cifs_fid_locks), GFP_KERNEL);
+	if (!fdlocks) {
+		kfree(cfile);
+		return NULL;
+	}
+
+	if (symlink_target) {
+		cfile->symlink_target = kstrdup(symlink_target, GFP_KERNEL);
+		if (!cfile->symlink_target) {
+			kfree(fdlocks);
+			kfree(cfile);
+			return NULL;
+		}
+	}
+
+	INIT_LIST_HEAD(&fdlocks->locks);
+	fdlocks->cfile = cfile;
+	cfile->llist = fdlocks;
+
+	cfile->count = 1;
+	cfile->pid = current->tgid;
+	cfile->uid = current_fsuid();
+	cfile->dentry = dget(dentry);
+	cfile->f_flags = file->f_flags;
+	cfile->invalidHandle = false;
+	cfile->deferred_close_scheduled = false;
+	cfile->tlink = cifs_get_tlink(tlink);
+	INIT_WORK(&cfile->oplock_break, cifs_oplock_break);
+	INIT_WORK(&cfile->put, cifsFileInfo_put_work);
+	INIT_DELAYED_WORK(&cfile->deferred, smb2_deferred_work_close);
+	mutex_init(&cfile->fh_mutex);
+	spin_lock_init(&cfile->file_info_lock);
+
+	cifs_sb_active(inode->i_sb);
+
+	/*
+	 * If the server returned a read oplock and we have mandatory brlocks,
+	 * set oplock level to None.
+	 */
+	if (server->ops->is_read_op(oplock) && cifs_has_mand_locks(cinode)) {
+		cifs_dbg(FYI, "Reset oplock val from read to None due to mand locks\n");
+		oplock = 0;
+	}
+
+	cifs_down_write(&cinode->lock_sem);
+	list_add(&fdlocks->llist, &cinode->llist);
+	up_write(&cinode->lock_sem);
+
+	spin_lock(&tcon->open_file_lock);
+	if (fid->pending_open->oplock != CIFS_OPLOCK_NO_CHANGE && oplock)
+		oplock = fid->pending_open->oplock;
+	list_del(&fid->pending_open->olist);
+
+	fid->purge_cache = false;
+	server->ops->set_fid(cfile, fid, oplock);
+
+	list_add(&cfile->tlist, &tcon->openFileList);
+	atomic_inc(&tcon->num_local_opens);
+
+	/* if readable file instance put first in list*/
+	spin_lock(&cinode->open_file_lock);
+	if (file->f_mode & FMODE_READ)
+		list_add(&cfile->flist, &cinode->openFileList);
+	else
+		list_add_tail(&cfile->flist, &cinode->openFileList);
+	spin_unlock(&cinode->open_file_lock);
+	spin_unlock(&tcon->open_file_lock);
+
+	if (fid->purge_cache)
+		cifs_zap_mapping(inode);
+
+	file->private_data = cfile;
+	return cfile;
+}
+
+struct cifsFileInfo *
+cifsFileInfo_get(struct cifsFileInfo *cifs_file)
+{
+	spin_lock(&cifs_file->file_info_lock);
+	cifsFileInfo_get_locked(cifs_file);
+	spin_unlock(&cifs_file->file_info_lock);
+	return cifs_file;
+}
+
+static void cifsFileInfo_put_final(struct cifsFileInfo *cifs_file)
+{
+	struct inode *inode = d_inode(cifs_file->dentry);
+	struct cifsInodeInfo *cifsi = CIFS_I(inode);
+	struct cifsLockInfo *li, *tmp;
+	struct super_block *sb = inode->i_sb;
+
+	/*
+	 * Delete any outstanding lock records. We'll lose them when the file
+	 * is closed anyway.
+	 */
+	cifs_down_write(&cifsi->lock_sem);
+	list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
+		list_del(&li->llist);
+		cifs_del_lock_waiters(li);
+		kfree(li);
+	}
+	list_del(&cifs_file->llist->llist);
+	kfree(cifs_file->llist);
+	up_write(&cifsi->lock_sem);
+
+	cifs_put_tlink(cifs_file->tlink);
+	dput(cifs_file->dentry);
+	cifs_sb_deactive(sb);
+	kfree(cifs_file->symlink_target);
+	kfree(cifs_file);
+}
+
+static void cifsFileInfo_put_work(struct work_struct *work)
+{
+	struct cifsFileInfo *cifs_file = container_of(work,
+			struct cifsFileInfo, put);
+
+	cifsFileInfo_put_final(cifs_file);
+}
+
+/**
+ * cifsFileInfo_put - release a reference of file priv data
+ *
+ * Always potentially wait for oplock handler. See _cifsFileInfo_put().
+ *
+ * @cifs_file:	cifs/smb3 specific info (eg refcounts) for an open file
+ */
+void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
+{
+	_cifsFileInfo_put(cifs_file, true, true);
+}
+
+/**
+ * _cifsFileInfo_put - release a reference of file priv data
+ *
+ * This may involve closing the filehandle @cifs_file out on the
+ * server. Must be called without holding tcon->open_file_lock,
+ * cinode->open_file_lock and cifs_file->file_info_lock.
+ *
+ * If @wait_for_oplock_handler is true and we are releasing the last
+ * reference, wait for any running oplock break handler of the file
+ * and cancel any pending one.
+ *
+ * @cifs_file:	cifs/smb3 specific info (eg refcounts) for an open file
+ * @wait_oplock_handler: must be false if called from oplock_break_handler
+ * @offload:	not offloaded on close and oplock breaks
+ *
+ */
+void _cifsFileInfo_put(struct cifsFileInfo *cifs_file,
+		       bool wait_oplock_handler, bool offload)
+{
+	struct inode *inode = d_inode(cifs_file->dentry);
+	struct cifs_tcon *tcon = tlink_tcon(cifs_file->tlink);
+	struct TCP_Server_Info *server = tcon->ses->server;
+	struct cifsInodeInfo *cifsi = CIFS_I(inode);
+	struct super_block *sb = inode->i_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+	struct cifs_fid fid = {};
+	struct cifs_pending_open open;
+	bool oplock_break_cancelled;
+
+	spin_lock(&tcon->open_file_lock);
+	spin_lock(&cifsi->open_file_lock);
+	spin_lock(&cifs_file->file_info_lock);
+	if (--cifs_file->count > 0) {
+		spin_unlock(&cifs_file->file_info_lock);
+		spin_unlock(&cifsi->open_file_lock);
+		spin_unlock(&tcon->open_file_lock);
+		return;
+	}
+	spin_unlock(&cifs_file->file_info_lock);
+
+	if (server->ops->get_lease_key)
+		server->ops->get_lease_key(inode, &fid);
+
+	/* store open in pending opens to make sure we don't miss lease break */
+	cifs_add_pending_open_locked(&fid, cifs_file->tlink, &open);
+
+	/* remove it from the lists */
+	list_del(&cifs_file->flist);
+	list_del(&cifs_file->tlist);
+	atomic_dec(&tcon->num_local_opens);
+
+	if (list_empty(&cifsi->openFileList)) {
+		cifs_dbg(FYI, "closing last open instance for inode %p\n",
+			 d_inode(cifs_file->dentry));
+		/*
+		 * In strict cache mode we need invalidate mapping on the last
+		 * close  because it may cause a error when we open this file
+		 * again and get at least level II oplock.
+		 */
+		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO)
+			set_bit(CIFS_INO_INVALID_MAPPING, &cifsi->flags);
+		cifs_set_oplock_level(cifsi, 0);
+	}
+
+	spin_unlock(&cifsi->open_file_lock);
+	spin_unlock(&tcon->open_file_lock);
+
+	oplock_break_cancelled = wait_oplock_handler ?
+		cancel_work_sync(&cifs_file->oplock_break) : false;
+
+	if (!tcon->need_reconnect && !cifs_file->invalidHandle) {
+		struct TCP_Server_Info *server = tcon->ses->server;
+		unsigned int xid;
+
+		xid = get_xid();
+		if (server->ops->close_getattr)
+			server->ops->close_getattr(xid, tcon, cifs_file);
+		else if (server->ops->close)
+			server->ops->close(xid, tcon, &cifs_file->fid);
+		_free_xid(xid);
+	}
+
+	if (oplock_break_cancelled)
+		cifs_done_oplock_break(cifsi);
+
+	cifs_del_pending_open(&open);
+
+	if (offload)
+		queue_work(fileinfo_put_wq, &cifs_file->put);
+	else
+		cifsFileInfo_put_final(cifs_file);
+}
+
+int cifs_open(struct inode *inode, struct file *file)
+
+{
+	int rc = -EACCES;
+	unsigned int xid;
+	__u32 oplock;
+	struct cifs_sb_info *cifs_sb;
+	struct TCP_Server_Info *server;
+	struct cifs_tcon *tcon;
+	struct tcon_link *tlink;
+	struct cifsFileInfo *cfile = NULL;
+	void *page;
+	const char *full_path;
+	bool posix_open_ok = false;
+	struct cifs_fid fid = {};
+	struct cifs_pending_open open;
+	struct cifs_open_info_data data = {};
+
+	xid = get_xid();
+
+	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb))) {
+		free_xid(xid);
+		return -EIO;
+	}
+
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		free_xid(xid);
+		return PTR_ERR(tlink);
+	}
+	tcon = tlink_tcon(tlink);
+	server = tcon->ses->server;
+
+	page = alloc_dentry_path();
+	full_path = build_path_from_dentry(file_dentry(file), page);
+	if (IS_ERR(full_path)) {
+		rc = PTR_ERR(full_path);
+		goto out;
+	}
+
+	cifs_dbg(FYI, "inode = 0x%p file flags are 0x%x for %s\n",
+		 inode, file->f_flags, full_path);
+
+	if (file->f_flags & O_DIRECT &&
+	    cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
+		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
+			file->f_op = &cifs_file_direct_nobrl_ops;
+		else
+			file->f_op = &cifs_file_direct_ops;
+	}
+
+	/* Get the cached handle as SMB2 close is deferred */
+	rc = cifs_get_readable_path(tcon, full_path, &cfile);
+	if (rc == 0) {
+		if (file->f_flags == cfile->f_flags) {
+			file->private_data = cfile;
+			spin_lock(&CIFS_I(inode)->deferred_lock);
+			cifs_del_deferred_close(cfile);
+			spin_unlock(&CIFS_I(inode)->deferred_lock);
+			goto use_cache;
+		} else {
+			_cifsFileInfo_put(cfile, true, false);
+		}
+	}
+
+	if (server->oplocks)
+		oplock = REQ_OPLOCK;
+	else
+		oplock = 0;
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if (!tcon->broken_posix_open && tcon->unix_ext &&
+	    cap_unix(tcon->ses) && (CIFS_UNIX_POSIX_PATH_OPS_CAP &
+				le64_to_cpu(tcon->fsUnixInfo.Capability))) {
+		/* can not refresh inode info since size could be stale */
+		rc = cifs_posix_open(full_path, &inode, inode->i_sb,
+				cifs_sb->ctx->file_mode /* ignored */,
+				file->f_flags, &oplock, &fid.netfid, xid);
+		if (rc == 0) {
+			cifs_dbg(FYI, "posix open succeeded\n");
+			posix_open_ok = true;
+		} else if ((rc == -EINVAL) || (rc == -EOPNOTSUPP)) {
+			if (tcon->ses->serverNOS)
+				cifs_dbg(VFS, "server %s of type %s returned unexpected error on SMB posix open, disabling posix open support. Check if server update available.\n",
+					 tcon->ses->ip_addr,
+					 tcon->ses->serverNOS);
+			tcon->broken_posix_open = true;
+		} else if ((rc != -EIO) && (rc != -EREMOTE) &&
+			 (rc != -EOPNOTSUPP)) /* path not found or net err */
+			goto out;
+		/*
+		 * Else fallthrough to retry open the old way on network i/o
+		 * or DFS errors.
+		 */
+	}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+	if (server->ops->get_lease_key)
+		server->ops->get_lease_key(inode, &fid);
+
+	cifs_add_pending_open(&fid, tlink, &open);
+
+	if (!posix_open_ok) {
+		if (server->ops->get_lease_key)
+			server->ops->get_lease_key(inode, &fid);
+
+		rc = cifs_nt_open(full_path, inode, cifs_sb, tcon, file->f_flags, &oplock, &fid,
+				  xid, &data);
+		if (rc) {
+			cifs_del_pending_open(&open);
+			goto out;
+		}
+	}
+
+	cfile = cifs_new_fileinfo(&fid, file, tlink, oplock, data.symlink_target);
+	if (cfile == NULL) {
+		if (server->ops->close)
+			server->ops->close(xid, tcon, &fid);
+		cifs_del_pending_open(&open);
+		rc = -ENOMEM;
+		goto out;
+	}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if ((oplock & CIFS_CREATE_ACTION) && !posix_open_ok && tcon->unix_ext) {
+		/*
+		 * Time to set mode which we can not set earlier due to
+		 * problems creating new read-only files.
+		 */
+		struct cifs_unix_set_info_args args = {
+			.mode	= inode->i_mode,
+			.uid	= INVALID_UID, /* no change */
+			.gid	= INVALID_GID, /* no change */
+			.ctime	= NO_CHANGE_64,
+			.atime	= NO_CHANGE_64,
+			.mtime	= NO_CHANGE_64,
+			.device	= 0,
+		};
+		CIFSSMBUnixSetFileInfo(xid, tcon, &args, fid.netfid,
+				       cfile->pid);
+	}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+use_cache:
+	fscache_use_cookie(cifs_inode_cookie(file_inode(file)),
+			   file->f_mode & FMODE_WRITE);
+	if (file->f_flags & O_DIRECT &&
+	    (!((file->f_flags & O_ACCMODE) != O_RDONLY) ||
+	     file->f_flags & O_APPEND))
+		cifs_invalidate_cache(file_inode(file),
+				      FSCACHE_INVAL_DIO_WRITE);
+
+out:
+	free_dentry_path(page);
+	free_xid(xid);
+	cifs_put_tlink(tlink);
+	cifs_free_open_info(&data);
+	return rc;
+}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+static int cifs_push_posix_locks(struct cifsFileInfo *cfile);
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+/*
+ * Try to reacquire byte range locks that were released when session
+ * to server was lost.
+ */
+static int
+cifs_relock_file(struct cifsFileInfo *cfile)
+{
+	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	int rc = 0;
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+	down_read_nested(&cinode->lock_sem, SINGLE_DEPTH_NESTING);
+	if (cinode->can_cache_brlcks) {
+		/* can cache locks - no need to relock */
+		up_read(&cinode->lock_sem);
+		return rc;
+	}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if (cap_unix(tcon->ses) &&
+	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+		rc = cifs_push_posix_locks(cfile);
+	else
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+		rc = tcon->ses->server->ops->push_mand_locks(cfile);
+
+	up_read(&cinode->lock_sem);
+	return rc;
+}
+
+static int
+cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
+{
+	int rc = -EACCES;
+	unsigned int xid;
+	__u32 oplock;
+	struct cifs_sb_info *cifs_sb;
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	struct cifsInodeInfo *cinode;
+	struct inode *inode;
+	void *page;
+	const char *full_path;
+	int desired_access;
+	int disposition = FILE_OPEN;
+	int create_options = CREATE_NOT_DIR;
+	struct cifs_open_parms oparms;
+
+	xid = get_xid();
+	mutex_lock(&cfile->fh_mutex);
+	if (!cfile->invalidHandle) {
+		mutex_unlock(&cfile->fh_mutex);
+		free_xid(xid);
+		return 0;
+	}
+
+	inode = d_inode(cfile->dentry);
+	cifs_sb = CIFS_SB(inode->i_sb);
+	tcon = tlink_tcon(cfile->tlink);
+	server = tcon->ses->server;
+
+	/*
+	 * Can not grab rename sem here because various ops, including those
+	 * that already have the rename sem can end up causing writepage to get
+	 * called and if the server was down that means we end up here, and we
+	 * can never tell if the caller already has the rename_sem.
+	 */
+	page = alloc_dentry_path();
+	full_path = build_path_from_dentry(cfile->dentry, page);
+	if (IS_ERR(full_path)) {
+		mutex_unlock(&cfile->fh_mutex);
+		free_dentry_path(page);
+		free_xid(xid);
+		return PTR_ERR(full_path);
+	}
+
+	cifs_dbg(FYI, "inode = 0x%p file flags 0x%x for %s\n",
+		 inode, cfile->f_flags, full_path);
+
+	if (tcon->ses->server->oplocks)
+		oplock = REQ_OPLOCK;
+	else
+		oplock = 0;
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if (tcon->unix_ext && cap_unix(tcon->ses) &&
+	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
+				le64_to_cpu(tcon->fsUnixInfo.Capability))) {
+		/*
+		 * O_CREAT, O_EXCL and O_TRUNC already had their effect on the
+		 * original open. Must mask them off for a reopen.
+		 */
+		unsigned int oflags = cfile->f_flags &
+						~(O_CREAT | O_EXCL | O_TRUNC);
+
+		rc = cifs_posix_open(full_path, NULL, inode->i_sb,
+				     cifs_sb->ctx->file_mode /* ignored */,
+				     oflags, &oplock, &cfile->fid.netfid, xid);
+		if (rc == 0) {
+			cifs_dbg(FYI, "posix reopen succeeded\n");
+			oparms.reconnect = true;
+			goto reopen_success;
+		}
+		/*
+		 * fallthrough to retry open the old way on errors, especially
+		 * in the reconnect path it is important to retry hard
+		 */
+	}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+	desired_access = cifs_convert_flags(cfile->f_flags);
+
+	/* O_SYNC also has bit for O_DSYNC so following check picks up either */
+	if (cfile->f_flags & O_SYNC)
+		create_options |= CREATE_WRITE_THROUGH;
+
+	if (cfile->f_flags & O_DIRECT)
+		create_options |= CREATE_NO_BUFFER;
+
+	if (server->ops->get_lease_key)
+		server->ops->get_lease_key(inode, &cfile->fid);
+
+	oparms = (struct cifs_open_parms) {
+		.tcon = tcon,
+		.cifs_sb = cifs_sb,
+		.desired_access = desired_access,
+		.create_options = cifs_create_options(cifs_sb, create_options),
+		.disposition = disposition,
+		.path = full_path,
+		.fid = &cfile->fid,
+		.reconnect = true,
+	};
+
+	/*
+	 * Can not refresh inode by passing in file_info buf to be returned by
+	 * ops->open and then calling get_inode_info with returned buf since
+	 * file might have write behind data that needs to be flushed and server
+	 * version of file size can be stale. If we knew for sure that inode was
+	 * not dirty locally we could do this.
+	 */
+	rc = server->ops->open(xid, &oparms, &oplock, NULL);
+	if (rc == -ENOENT && oparms.reconnect == false) {
+		/* durable handle timeout is expired - open the file again */
+		rc = server->ops->open(xid, &oparms, &oplock, NULL);
+		/* indicate that we need to relock the file */
+		oparms.reconnect = true;
+	}
+
+	if (rc) {
+		mutex_unlock(&cfile->fh_mutex);
+		cifs_dbg(FYI, "cifs_reopen returned 0x%x\n", rc);
+		cifs_dbg(FYI, "oplock: %d\n", oplock);
+		goto reopen_error_exit;
+	}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+reopen_success:
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+	cfile->invalidHandle = false;
+	mutex_unlock(&cfile->fh_mutex);
+	cinode = CIFS_I(inode);
+
+	if (can_flush) {
+		rc = filemap_write_and_wait(inode->i_mapping);
+		if (!is_interrupt_error(rc))
+			mapping_set_error(inode->i_mapping, rc);
+
+		if (tcon->posix_extensions)
+			rc = smb311_posix_get_inode_info(&inode, full_path, inode->i_sb, xid);
+		else if (tcon->unix_ext)
+			rc = cifs_get_inode_info_unix(&inode, full_path,
+						      inode->i_sb, xid);
+		else
+			rc = cifs_get_inode_info(&inode, full_path, NULL,
+						 inode->i_sb, xid, NULL);
+	}
+	/*
+	 * Else we are writing out data to server already and could deadlock if
+	 * we tried to flush data, and since we do not know if we have data that
+	 * would invalidate the current end of file on the server we can not go
+	 * to the server to get the new inode info.
+	 */
+
+	/*
+	 * If the server returned a read oplock and we have mandatory brlocks,
+	 * set oplock level to None.
+	 */
+	if (server->ops->is_read_op(oplock) && cifs_has_mand_locks(cinode)) {
+		cifs_dbg(FYI, "Reset oplock val from read to None due to mand locks\n");
+		oplock = 0;
+	}
+
+	server->ops->set_fid(cfile, &cfile->fid, oplock);
+	if (oparms.reconnect)
+		cifs_relock_file(cfile);
+
+reopen_error_exit:
+	free_dentry_path(page);
+	free_xid(xid);
+	return rc;
+}
+
+void smb2_deferred_work_close(struct work_struct *work)
+{
+	struct cifsFileInfo *cfile = container_of(work,
+			struct cifsFileInfo, deferred.work);
+
+	spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+	cifs_del_deferred_close(cfile);
+	cfile->deferred_close_scheduled = false;
+	spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+	_cifsFileInfo_put(cfile, true, false);
+}
+
+int cifs_close(struct inode *inode, struct file *file)
+{
+	struct cifsFileInfo *cfile;
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifs_deferred_close *dclose;
+
+	cifs_fscache_unuse_inode_cookie(inode, file->f_mode & FMODE_WRITE);
+
+	if (file->private_data != NULL) {
+		cfile = file->private_data;
+		file->private_data = NULL;
+		dclose = kmalloc(sizeof(struct cifs_deferred_close), GFP_KERNEL);
+		if ((cifs_sb->ctx->closetimeo && cinode->oplock == CIFS_CACHE_RHW_FLG)
+		    && cinode->lease_granted &&
+		    !test_bit(CIFS_INO_CLOSE_ON_LOCK, &cinode->flags) &&
+		    dclose) {
+			if (test_and_clear_bit(CIFS_INO_MODIFIED_ATTR, &cinode->flags)) {
+				inode->i_ctime = inode->i_mtime = current_time(inode);
+			}
+			spin_lock(&cinode->deferred_lock);
+			cifs_add_deferred_close(cfile, dclose);
+			if (cfile->deferred_close_scheduled &&
+			    delayed_work_pending(&cfile->deferred)) {
+				/*
+				 * If there is no pending work, mod_delayed_work queues new work.
+				 * So, Increase the ref count to avoid use-after-free.
+				 */
+				if (!mod_delayed_work(deferredclose_wq,
+						&cfile->deferred, cifs_sb->ctx->closetimeo))
+					cifsFileInfo_get(cfile);
+			} else {
+				/* Deferred close for files */
+				queue_delayed_work(deferredclose_wq,
+						&cfile->deferred, cifs_sb->ctx->closetimeo);
+				cfile->deferred_close_scheduled = true;
+				spin_unlock(&cinode->deferred_lock);
+				return 0;
+			}
+			spin_unlock(&cinode->deferred_lock);
+			_cifsFileInfo_put(cfile, true, false);
+		} else {
+			_cifsFileInfo_put(cfile, true, false);
+			kfree(dclose);
+		}
+	}
+
+	/* return code from the ->release op is always ignored */
+	return 0;
+}
+
+void
+cifs_reopen_persistent_handles(struct cifs_tcon *tcon)
+{
+	struct cifsFileInfo *open_file, *tmp;
+	struct list_head tmp_list;
+
+	if (!tcon->use_persistent || !tcon->need_reopen_files)
+		return;
+
+	tcon->need_reopen_files = false;
+
+	cifs_dbg(FYI, "Reopen persistent handles\n");
+	INIT_LIST_HEAD(&tmp_list);
+
+	/* list all files open on tree connection, reopen resilient handles  */
+	spin_lock(&tcon->open_file_lock);
+	list_for_each_entry(open_file, &tcon->openFileList, tlist) {
+		if (!open_file->invalidHandle)
+			continue;
+		cifsFileInfo_get(open_file);
+		list_add_tail(&open_file->rlist, &tmp_list);
+	}
+	spin_unlock(&tcon->open_file_lock);
+
+	list_for_each_entry_safe(open_file, tmp, &tmp_list, rlist) {
+		if (cifs_reopen_file(open_file, false /* do not flush */))
+			tcon->need_reopen_files = true;
+		list_del_init(&open_file->rlist);
+		cifsFileInfo_put(open_file);
+	}
+}
+
+int cifs_closedir(struct inode *inode, struct file *file)
+{
+	int rc = 0;
+	unsigned int xid;
+	struct cifsFileInfo *cfile = file->private_data;
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	char *buf;
+
+	cifs_dbg(FYI, "Closedir inode = 0x%p\n", inode);
+
+	if (cfile == NULL)
+		return rc;
+
+	xid = get_xid();
+	tcon = tlink_tcon(cfile->tlink);
+	server = tcon->ses->server;
+
+	cifs_dbg(FYI, "Freeing private data in close dir\n");
+	spin_lock(&cfile->file_info_lock);
+	if (server->ops->dir_needs_close(cfile)) {
+		cfile->invalidHandle = true;
+		spin_unlock(&cfile->file_info_lock);
+		if (server->ops->close_dir)
+			rc = server->ops->close_dir(xid, tcon, &cfile->fid);
+		else
+			rc = -ENOSYS;
+		cifs_dbg(FYI, "Closing uncompleted readdir with rc %d\n", rc);
+		/* not much we can do if it fails anyway, ignore rc */
+		rc = 0;
+	} else
+		spin_unlock(&cfile->file_info_lock);
+
+	buf = cfile->srch_inf.ntwrk_buf_start;
+	if (buf) {
+		cifs_dbg(FYI, "closedir free smb buf in srch struct\n");
+		cfile->srch_inf.ntwrk_buf_start = NULL;
+		if (cfile->srch_inf.smallBuf)
+			cifs_small_buf_release(buf);
+		else
+			cifs_buf_release(buf);
+	}
+
+	cifs_put_tlink(cfile->tlink);
+	kfree(file->private_data);
+	file->private_data = NULL;
+	/* BB can we lock the filestruct while this is going on? */
+	free_xid(xid);
+	return rc;
+}
+
+static struct cifsLockInfo *
+cifs_lock_init(__u64 offset, __u64 length, __u8 type, __u16 flags)
+{
+	struct cifsLockInfo *lock =
+		kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
+	if (!lock)
+		return lock;
+	lock->offset = offset;
+	lock->length = length;
+	lock->type = type;
+	lock->pid = current->tgid;
+	lock->flags = flags;
+	INIT_LIST_HEAD(&lock->blist);
+	init_waitqueue_head(&lock->block_q);
+	return lock;
+}
+
+void
+cifs_del_lock_waiters(struct cifsLockInfo *lock)
+{
+	struct cifsLockInfo *li, *tmp;
+	list_for_each_entry_safe(li, tmp, &lock->blist, blist) {
+		list_del_init(&li->blist);
+		wake_up(&li->block_q);
+	}
+}
+
+#define CIFS_LOCK_OP	0
+#define CIFS_READ_OP	1
+#define CIFS_WRITE_OP	2
+
+/* @rw_check : 0 - no op, 1 - read, 2 - write */
+static bool
+cifs_find_fid_lock_conflict(struct cifs_fid_locks *fdlocks, __u64 offset,
+			    __u64 length, __u8 type, __u16 flags,
+			    struct cifsFileInfo *cfile,
+			    struct cifsLockInfo **conf_lock, int rw_check)
+{
+	struct cifsLockInfo *li;
+	struct cifsFileInfo *cur_cfile = fdlocks->cfile;
+	struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
+
+	list_for_each_entry(li, &fdlocks->locks, llist) {
+		if (offset + length <= li->offset ||
+		    offset >= li->offset + li->length)
+			continue;
+		if (rw_check != CIFS_LOCK_OP && current->tgid == li->pid &&
+		    server->ops->compare_fids(cfile, cur_cfile)) {
+			/* shared lock prevents write op through the same fid */
+			if (!(li->type & server->vals->shared_lock_type) ||
+			    rw_check != CIFS_WRITE_OP)
+				continue;
+		}
+		if ((type & server->vals->shared_lock_type) &&
+		    ((server->ops->compare_fids(cfile, cur_cfile) &&
+		     current->tgid == li->pid) || type == li->type))
+			continue;
+		if (rw_check == CIFS_LOCK_OP &&
+		    (flags & FL_OFDLCK) && (li->flags & FL_OFDLCK) &&
+		    server->ops->compare_fids(cfile, cur_cfile))
+			continue;
+		if (conf_lock)
+			*conf_lock = li;
+		return true;
+	}
+	return false;
+}
+
+bool
+cifs_find_lock_conflict(struct cifsFileInfo *cfile, __u64 offset, __u64 length,
+			__u8 type, __u16 flags,
+			struct cifsLockInfo **conf_lock, int rw_check)
+{
+	bool rc = false;
+	struct cifs_fid_locks *cur;
+	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
+
+	list_for_each_entry(cur, &cinode->llist, llist) {
+		rc = cifs_find_fid_lock_conflict(cur, offset, length, type,
+						 flags, cfile, conf_lock,
+						 rw_check);
+		if (rc)
+			break;
+	}
+
+	return rc;
+}
+
+/*
+ * Check if there is another lock that prevents us to set the lock (mandatory
+ * style). If such a lock exists, update the flock structure with its
+ * properties. Otherwise, set the flock type to F_UNLCK if we can cache brlocks
+ * or leave it the same if we can't. Returns 0 if we don't need to request to
+ * the server or 1 otherwise.
+ */
+static int
+cifs_lock_test(struct cifsFileInfo *cfile, __u64 offset, __u64 length,
+	       __u8 type, struct file_lock *flock)
+{
+	int rc = 0;
+	struct cifsLockInfo *conf_lock;
+	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
+	struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
+	bool exist;
+
+	down_read(&cinode->lock_sem);
+
+	exist = cifs_find_lock_conflict(cfile, offset, length, type,
+					flock->fl_flags, &conf_lock,
+					CIFS_LOCK_OP);
+	if (exist) {
+		flock->fl_start = conf_lock->offset;
+		flock->fl_end = conf_lock->offset + conf_lock->length - 1;
+		flock->fl_pid = conf_lock->pid;
+		if (conf_lock->type & server->vals->shared_lock_type)
+			flock->fl_type = F_RDLCK;
+		else
+			flock->fl_type = F_WRLCK;
+	} else if (!cinode->can_cache_brlcks)
+		rc = 1;
+	else
+		flock->fl_type = F_UNLCK;
+
+	up_read(&cinode->lock_sem);
+	return rc;
+}
+
+static void
+cifs_lock_add(struct cifsFileInfo *cfile, struct cifsLockInfo *lock)
+{
+	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
+	cifs_down_write(&cinode->lock_sem);
+	list_add_tail(&lock->llist, &cfile->llist->locks);
+	up_write(&cinode->lock_sem);
+}
+
+/*
+ * Set the byte-range lock (mandatory style). Returns:
+ * 1) 0, if we set the lock and don't need to request to the server;
+ * 2) 1, if no locks prevent us but we need to request to the server;
+ * 3) -EACCES, if there is a lock that prevents us and wait is false.
+ */
+static int
+cifs_lock_add_if(struct cifsFileInfo *cfile, struct cifsLockInfo *lock,
+		 bool wait)
+{
+	struct cifsLockInfo *conf_lock;
+	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
+	bool exist;
+	int rc = 0;
+
+try_again:
+	exist = false;
+	cifs_down_write(&cinode->lock_sem);
+
+	exist = cifs_find_lock_conflict(cfile, lock->offset, lock->length,
+					lock->type, lock->flags, &conf_lock,
+					CIFS_LOCK_OP);
+	if (!exist && cinode->can_cache_brlcks) {
+		list_add_tail(&lock->llist, &cfile->llist->locks);
+		up_write(&cinode->lock_sem);
+		return rc;
+	}
+
+	if (!exist)
+		rc = 1;
+	else if (!wait)
+		rc = -EACCES;
+	else {
+		list_add_tail(&lock->blist, &conf_lock->blist);
+		up_write(&cinode->lock_sem);
+		rc = wait_event_interruptible(lock->block_q,
+					(lock->blist.prev == &lock->blist) &&
+					(lock->blist.next == &lock->blist));
+		if (!rc)
+			goto try_again;
+		cifs_down_write(&cinode->lock_sem);
+		list_del_init(&lock->blist);
+	}
+
+	up_write(&cinode->lock_sem);
+	return rc;
+}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+/*
+ * Check if there is another lock that prevents us to set the lock (posix
+ * style). If such a lock exists, update the flock structure with its
+ * properties. Otherwise, set the flock type to F_UNLCK if we can cache brlocks
+ * or leave it the same if we can't. Returns 0 if we don't need to request to
+ * the server or 1 otherwise.
+ */
+static int
+cifs_posix_lock_test(struct file *file, struct file_lock *flock)
+{
+	int rc = 0;
+	struct cifsInodeInfo *cinode = CIFS_I(file_inode(file));
+	unsigned char saved_type = flock->fl_type;
+
+	if ((flock->fl_flags & FL_POSIX) == 0)
+		return 1;
+
+	down_read(&cinode->lock_sem);
+	posix_test_lock(file, flock);
+
+	if (flock->fl_type == F_UNLCK && !cinode->can_cache_brlcks) {
+		flock->fl_type = saved_type;
+		rc = 1;
+	}
+
+	up_read(&cinode->lock_sem);
+	return rc;
+}
+
+/*
+ * Set the byte-range lock (posix style). Returns:
+ * 1) <0, if the error occurs while setting the lock;
+ * 2) 0, if we set the lock and don't need to request to the server;
+ * 3) FILE_LOCK_DEFERRED, if we will wait for some other file_lock;
+ * 4) FILE_LOCK_DEFERRED + 1, if we need to request to the server.
+ */
+static int
+cifs_posix_lock_set(struct file *file, struct file_lock *flock)
+{
+	struct cifsInodeInfo *cinode = CIFS_I(file_inode(file));
+	int rc = FILE_LOCK_DEFERRED + 1;
+
+	if ((flock->fl_flags & FL_POSIX) == 0)
+		return rc;
+
+	cifs_down_write(&cinode->lock_sem);
+	if (!cinode->can_cache_brlcks) {
+		up_write(&cinode->lock_sem);
+		return rc;
+	}
+
+	rc = posix_lock_file(file, flock, NULL);
+	up_write(&cinode->lock_sem);
+	return rc;
+}
+
+int
+cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
+{
+	unsigned int xid;
+	int rc = 0, stored_rc;
+	struct cifsLockInfo *li, *tmp;
+	struct cifs_tcon *tcon;
+	unsigned int num, max_num, max_buf;
+	LOCKING_ANDX_RANGE *buf, *cur;
+	static const int types[] = {
+		LOCKING_ANDX_LARGE_FILES,
+		LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES
+	};
+	int i;
+
+	xid = get_xid();
+	tcon = tlink_tcon(cfile->tlink);
+
+	/*
+	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
+	 * and check it before using.
+	 */
+	max_buf = tcon->ses->server->maxBuf;
+	if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE))) {
+		free_xid(xid);
+		return -EINVAL;
+	}
+
+	BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) >
+		     PAGE_SIZE);
+	max_buf = min_t(unsigned int, max_buf - sizeof(struct smb_hdr),
+			PAGE_SIZE);
+	max_num = (max_buf - sizeof(struct smb_hdr)) /
+						sizeof(LOCKING_ANDX_RANGE);
+	buf = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
+	if (!buf) {
+		free_xid(xid);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < 2; i++) {
+		cur = buf;
+		num = 0;
+		list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
+			if (li->type != types[i])
+				continue;
+			cur->Pid = cpu_to_le16(li->pid);
+			cur->LengthLow = cpu_to_le32((u32)li->length);
+			cur->LengthHigh = cpu_to_le32((u32)(li->length>>32));
+			cur->OffsetLow = cpu_to_le32((u32)li->offset);
+			cur->OffsetHigh = cpu_to_le32((u32)(li->offset>>32));
+			if (++num == max_num) {
+				stored_rc = cifs_lockv(xid, tcon,
+						       cfile->fid.netfid,
+						       (__u8)li->type, 0, num,
+						       buf);
+				if (stored_rc)
+					rc = stored_rc;
+				cur = buf;
+				num = 0;
+			} else
+				cur++;
+		}
+
+		if (num) {
+			stored_rc = cifs_lockv(xid, tcon, cfile->fid.netfid,
+					       (__u8)types[i], 0, num, buf);
+			if (stored_rc)
+				rc = stored_rc;
+		}
+	}
+
+	kfree(buf);
+	free_xid(xid);
+	return rc;
+}
+
+static __u32
+hash_lockowner(fl_owner_t owner)
+{
+	return cifs_lock_secret ^ hash32_ptr((const void *)owner);
+}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+struct lock_to_push {
+	struct list_head llist;
+	__u64 offset;
+	__u64 length;
+	__u32 pid;
+	__u16 netfid;
+	__u8 type;
+};
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+static int
+cifs_push_posix_locks(struct cifsFileInfo *cfile)
+{
+	struct inode *inode = d_inode(cfile->dentry);
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	struct file_lock *flock;
+	struct file_lock_context *flctx = inode->i_flctx;
+	unsigned int count = 0, i;
+	int rc = 0, xid, type;
+	struct list_head locks_to_send, *el;
+	struct lock_to_push *lck, *tmp;
+	__u64 length;
+
+	xid = get_xid();
+
+	if (!flctx)
+		goto out;
+
+	spin_lock(&flctx->flc_lock);
+	list_for_each(el, &flctx->flc_posix) {
+		count++;
+	}
+	spin_unlock(&flctx->flc_lock);
+
+	INIT_LIST_HEAD(&locks_to_send);
+
+	/*
+	 * Allocating count locks is enough because no FL_POSIX locks can be
+	 * added to the list while we are holding cinode->lock_sem that
+	 * protects locking operations of this inode.
+	 */
+	for (i = 0; i < count; i++) {
+		lck = kmalloc(sizeof(struct lock_to_push), GFP_KERNEL);
+		if (!lck) {
+			rc = -ENOMEM;
+			goto err_out;
+		}
+		list_add_tail(&lck->llist, &locks_to_send);
+	}
+
+	el = locks_to_send.next;
+	spin_lock(&flctx->flc_lock);
+	list_for_each_entry(flock, &flctx->flc_posix, fl_list) {
+		if (el == &locks_to_send) {
+			/*
+			 * The list ended. We don't have enough allocated
+			 * structures - something is really wrong.
+			 */
+			cifs_dbg(VFS, "Can't push all brlocks!\n");
+			break;
+		}
+		length = cifs_flock_len(flock);
+		if (flock->fl_type == F_RDLCK || flock->fl_type == F_SHLCK)
+			type = CIFS_RDLCK;
+		else
+			type = CIFS_WRLCK;
+		lck = list_entry(el, struct lock_to_push, llist);
+		lck->pid = hash_lockowner(flock->fl_owner);
+		lck->netfid = cfile->fid.netfid;
+		lck->length = length;
+		lck->type = type;
+		lck->offset = flock->fl_start;
+	}
+	spin_unlock(&flctx->flc_lock);
+
+	list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
+		int stored_rc;
+
+		stored_rc = CIFSSMBPosixLock(xid, tcon, lck->netfid, lck->pid,
+					     lck->offset, lck->length, NULL,
+					     lck->type, 0);
+		if (stored_rc)
+			rc = stored_rc;
+		list_del(&lck->llist);
+		kfree(lck);
+	}
+
+out:
+	free_xid(xid);
+	return rc;
+err_out:
+	list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
+		list_del(&lck->llist);
+		kfree(lck);
+	}
+	goto out;
+}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+static int
+cifs_push_locks(struct cifsFileInfo *cfile)
+{
+	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	int rc = 0;
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+	/* we are going to update can_cache_brlcks here - need a write access */
+	cifs_down_write(&cinode->lock_sem);
+	if (!cinode->can_cache_brlcks) {
+		up_write(&cinode->lock_sem);
+		return rc;
+	}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if (cap_unix(tcon->ses) &&
+	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+		rc = cifs_push_posix_locks(cfile);
+	else
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+		rc = tcon->ses->server->ops->push_mand_locks(cfile);
+
+	cinode->can_cache_brlcks = false;
+	up_write(&cinode->lock_sem);
+	return rc;
+}
+
+static void
+cifs_read_flock(struct file_lock *flock, __u32 *type, int *lock, int *unlock,
+		bool *wait_flag, struct TCP_Server_Info *server)
+{
+	if (flock->fl_flags & FL_POSIX)
+		cifs_dbg(FYI, "Posix\n");
+	if (flock->fl_flags & FL_FLOCK)
+		cifs_dbg(FYI, "Flock\n");
+	if (flock->fl_flags & FL_SLEEP) {
+		cifs_dbg(FYI, "Blocking lock\n");
+		*wait_flag = true;
+	}
+	if (flock->fl_flags & FL_ACCESS)
+		cifs_dbg(FYI, "Process suspended by mandatory locking - not implemented yet\n");
+	if (flock->fl_flags & FL_LEASE)
+		cifs_dbg(FYI, "Lease on file - not implemented yet\n");
+	if (flock->fl_flags &
+	    (~(FL_POSIX | FL_FLOCK | FL_SLEEP |
+	       FL_ACCESS | FL_LEASE | FL_CLOSE | FL_OFDLCK)))
+		cifs_dbg(FYI, "Unknown lock flags 0x%x\n", flock->fl_flags);
+
+	*type = server->vals->large_lock_type;
+	if (flock->fl_type == F_WRLCK) {
+		cifs_dbg(FYI, "F_WRLCK\n");
+		*type |= server->vals->exclusive_lock_type;
+		*lock = 1;
+	} else if (flock->fl_type == F_UNLCK) {
+		cifs_dbg(FYI, "F_UNLCK\n");
+		*type |= server->vals->unlock_lock_type;
+		*unlock = 1;
+		/* Check if unlock includes more than one lock range */
+	} else if (flock->fl_type == F_RDLCK) {
+		cifs_dbg(FYI, "F_RDLCK\n");
+		*type |= server->vals->shared_lock_type;
+		*lock = 1;
+	} else if (flock->fl_type == F_EXLCK) {
+		cifs_dbg(FYI, "F_EXLCK\n");
+		*type |= server->vals->exclusive_lock_type;
+		*lock = 1;
+	} else if (flock->fl_type == F_SHLCK) {
+		cifs_dbg(FYI, "F_SHLCK\n");
+		*type |= server->vals->shared_lock_type;
+		*lock = 1;
+	} else
+		cifs_dbg(FYI, "Unknown type of lock\n");
+}
+
+static int
+cifs_getlk(struct file *file, struct file_lock *flock, __u32 type,
+	   bool wait_flag, bool posix_lck, unsigned int xid)
+{
+	int rc = 0;
+	__u64 length = cifs_flock_len(flock);
+	struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	struct TCP_Server_Info *server = tcon->ses->server;
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	__u16 netfid = cfile->fid.netfid;
+
+	if (posix_lck) {
+		int posix_lock_type;
+
+		rc = cifs_posix_lock_test(file, flock);
+		if (!rc)
+			return rc;
+
+		if (type & server->vals->shared_lock_type)
+			posix_lock_type = CIFS_RDLCK;
+		else
+			posix_lock_type = CIFS_WRLCK;
+		rc = CIFSSMBPosixLock(xid, tcon, netfid,
+				      hash_lockowner(flock->fl_owner),
+				      flock->fl_start, length, flock,
+				      posix_lock_type, wait_flag);
+		return rc;
+	}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+	rc = cifs_lock_test(cfile, flock->fl_start, length, type, flock);
+	if (!rc)
+		return rc;
+
+	/* BB we could chain these into one lock request BB */
+	rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length, type,
+				    1, 0, false);
+	if (rc == 0) {
+		rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
+					    type, 0, 1, false);
+		flock->fl_type = F_UNLCK;
+		if (rc != 0)
+			cifs_dbg(VFS, "Error unlocking previously locked range %d during test of lock\n",
+				 rc);
+		return 0;
+	}
+
+	if (type & server->vals->shared_lock_type) {
+		flock->fl_type = F_WRLCK;
+		return 0;
+	}
+
+	type &= ~server->vals->exclusive_lock_type;
+
+	rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
+				    type | server->vals->shared_lock_type,
+				    1, 0, false);
+	if (rc == 0) {
+		rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
+			type | server->vals->shared_lock_type, 0, 1, false);
+		flock->fl_type = F_RDLCK;
+		if (rc != 0)
+			cifs_dbg(VFS, "Error unlocking previously locked range %d during test of lock\n",
+				 rc);
+	} else
+		flock->fl_type = F_WRLCK;
+
+	return 0;
+}
+
+void
+cifs_move_llist(struct list_head *source, struct list_head *dest)
+{
+	struct list_head *li, *tmp;
+	list_for_each_safe(li, tmp, source)
+		list_move(li, dest);
+}
+
+void
+cifs_free_llist(struct list_head *llist)
+{
+	struct cifsLockInfo *li, *tmp;
+	list_for_each_entry_safe(li, tmp, llist, llist) {
+		cifs_del_lock_waiters(li);
+		list_del(&li->llist);
+		kfree(li);
+	}
+}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+int
+cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
+		  unsigned int xid)
+{
+	int rc = 0, stored_rc;
+	static const int types[] = {
+		LOCKING_ANDX_LARGE_FILES,
+		LOCKING_ANDX_SHARED_LOCK | LOCKING_ANDX_LARGE_FILES
+	};
+	unsigned int i;
+	unsigned int max_num, num, max_buf;
+	LOCKING_ANDX_RANGE *buf, *cur;
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
+	struct cifsLockInfo *li, *tmp;
+	__u64 length = cifs_flock_len(flock);
+	struct list_head tmp_llist;
+
+	INIT_LIST_HEAD(&tmp_llist);
+
+	/*
+	 * Accessing maxBuf is racy with cifs_reconnect - need to store value
+	 * and check it before using.
+	 */
+	max_buf = tcon->ses->server->maxBuf;
+	if (max_buf < (sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE)))
+		return -EINVAL;
+
+	BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) >
+		     PAGE_SIZE);
+	max_buf = min_t(unsigned int, max_buf - sizeof(struct smb_hdr),
+			PAGE_SIZE);
+	max_num = (max_buf - sizeof(struct smb_hdr)) /
+						sizeof(LOCKING_ANDX_RANGE);
+	buf = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	cifs_down_write(&cinode->lock_sem);
+	for (i = 0; i < 2; i++) {
+		cur = buf;
+		num = 0;
+		list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
+			if (flock->fl_start > li->offset ||
+			    (flock->fl_start + length) <
+			    (li->offset + li->length))
+				continue;
+			if (current->tgid != li->pid)
+				continue;
+			if (types[i] != li->type)
+				continue;
+			if (cinode->can_cache_brlcks) {
+				/*
+				 * We can cache brlock requests - simply remove
+				 * a lock from the file's list.
+				 */
+				list_del(&li->llist);
+				cifs_del_lock_waiters(li);
+				kfree(li);
+				continue;
+			}
+			cur->Pid = cpu_to_le16(li->pid);
+			cur->LengthLow = cpu_to_le32((u32)li->length);
+			cur->LengthHigh = cpu_to_le32((u32)(li->length>>32));
+			cur->OffsetLow = cpu_to_le32((u32)li->offset);
+			cur->OffsetHigh = cpu_to_le32((u32)(li->offset>>32));
+			/*
+			 * We need to save a lock here to let us add it again to
+			 * the file's list if the unlock range request fails on
+			 * the server.
+			 */
+			list_move(&li->llist, &tmp_llist);
+			if (++num == max_num) {
+				stored_rc = cifs_lockv(xid, tcon,
+						       cfile->fid.netfid,
+						       li->type, num, 0, buf);
+				if (stored_rc) {
+					/*
+					 * We failed on the unlock range
+					 * request - add all locks from the tmp
+					 * list to the head of the file's list.
+					 */
+					cifs_move_llist(&tmp_llist,
+							&cfile->llist->locks);
+					rc = stored_rc;
+				} else
+					/*
+					 * The unlock range request succeed -
+					 * free the tmp list.
+					 */
+					cifs_free_llist(&tmp_llist);
+				cur = buf;
+				num = 0;
+			} else
+				cur++;
+		}
+		if (num) {
+			stored_rc = cifs_lockv(xid, tcon, cfile->fid.netfid,
+					       types[i], num, 0, buf);
+			if (stored_rc) {
+				cifs_move_llist(&tmp_llist,
+						&cfile->llist->locks);
+				rc = stored_rc;
+			} else
+				cifs_free_llist(&tmp_llist);
+		}
+	}
+
+	up_write(&cinode->lock_sem);
+	kfree(buf);
+	return rc;
+}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+static int
+cifs_setlk(struct file *file, struct file_lock *flock, __u32 type,
+	   bool wait_flag, bool posix_lck, int lock, int unlock,
+	   unsigned int xid)
+{
+	int rc = 0;
+	__u64 length = cifs_flock_len(flock);
+	struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	struct TCP_Server_Info *server = tcon->ses->server;
+	struct inode *inode = d_inode(cfile->dentry);
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if (posix_lck) {
+		int posix_lock_type;
+
+		rc = cifs_posix_lock_set(file, flock);
+		if (rc <= FILE_LOCK_DEFERRED)
+			return rc;
+
+		if (type & server->vals->shared_lock_type)
+			posix_lock_type = CIFS_RDLCK;
+		else
+			posix_lock_type = CIFS_WRLCK;
+
+		if (unlock == 1)
+			posix_lock_type = CIFS_UNLCK;
+
+		rc = CIFSSMBPosixLock(xid, tcon, cfile->fid.netfid,
+				      hash_lockowner(flock->fl_owner),
+				      flock->fl_start, length,
+				      NULL, posix_lock_type, wait_flag);
+		goto out;
+	}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+	if (lock) {
+		struct cifsLockInfo *lock;
+
+		lock = cifs_lock_init(flock->fl_start, length, type,
+				      flock->fl_flags);
+		if (!lock)
+			return -ENOMEM;
+
+		rc = cifs_lock_add_if(cfile, lock, wait_flag);
+		if (rc < 0) {
+			kfree(lock);
+			return rc;
+		}
+		if (!rc)
+			goto out;
+
+		/*
+		 * Windows 7 server can delay breaking lease from read to None
+		 * if we set a byte-range lock on a file - break it explicitly
+		 * before sending the lock to the server to be sure the next
+		 * read won't conflict with non-overlapted locks due to
+		 * pagereading.
+		 */
+		if (!CIFS_CACHE_WRITE(CIFS_I(inode)) &&
+					CIFS_CACHE_READ(CIFS_I(inode))) {
+			cifs_zap_mapping(inode);
+			cifs_dbg(FYI, "Set no oplock for inode=%p due to mand locks\n",
+				 inode);
+			CIFS_I(inode)->oplock = 0;
+		}
+
+		rc = server->ops->mand_lock(xid, cfile, flock->fl_start, length,
+					    type, 1, 0, wait_flag);
+		if (rc) {
+			kfree(lock);
+			return rc;
+		}
+
+		cifs_lock_add(cfile, lock);
+	} else if (unlock)
+		rc = server->ops->mand_unlock_range(cfile, flock, xid);
+
+out:
+	if ((flock->fl_flags & FL_POSIX) || (flock->fl_flags & FL_FLOCK)) {
+		/*
+		 * If this is a request to remove all locks because we
+		 * are closing the file, it doesn't matter if the
+		 * unlocking failed as both cifs.ko and the SMB server
+		 * remove the lock on file close
+		 */
+		if (rc) {
+			cifs_dbg(VFS, "%s failed rc=%d\n", __func__, rc);
+			if (!(flock->fl_flags & FL_CLOSE))
+				return rc;
+		}
+		rc = locks_lock_file_wait(file, flock);
+	}
+	return rc;
+}
+
+int cifs_flock(struct file *file, int cmd, struct file_lock *fl)
+{
+	int rc, xid;
+	int lock = 0, unlock = 0;
+	bool wait_flag = false;
+	bool posix_lck = false;
+	struct cifs_sb_info *cifs_sb;
+	struct cifs_tcon *tcon;
+	struct cifsFileInfo *cfile;
+	__u32 type;
+
+	xid = get_xid();
+
+	if (!(fl->fl_flags & FL_FLOCK)) {
+		rc = -ENOLCK;
+		free_xid(xid);
+		return rc;
+	}
+
+	cfile = (struct cifsFileInfo *)file->private_data;
+	tcon = tlink_tcon(cfile->tlink);
+
+	cifs_read_flock(fl, &type, &lock, &unlock, &wait_flag,
+			tcon->ses->server);
+	cifs_sb = CIFS_FILE_SB(file);
+
+	if (cap_unix(tcon->ses) &&
+	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+		posix_lck = true;
+
+	if (!lock && !unlock) {
+		/*
+		 * if no lock or unlock then nothing to do since we do not
+		 * know what it is
+		 */
+		rc = -EOPNOTSUPP;
+		free_xid(xid);
+		return rc;
+	}
+
+	rc = cifs_setlk(file, fl, type, wait_flag, posix_lck, lock, unlock,
+			xid);
+	free_xid(xid);
+	return rc;
+
+
+}
+
+int cifs_lock(struct file *file, int cmd, struct file_lock *flock)
+{
+	int rc, xid;
+	int lock = 0, unlock = 0;
+	bool wait_flag = false;
+	bool posix_lck = false;
+	struct cifs_sb_info *cifs_sb;
+	struct cifs_tcon *tcon;
+	struct cifsFileInfo *cfile;
+	__u32 type;
+
+	rc = -EACCES;
+	xid = get_xid();
+
+	cifs_dbg(FYI, "%s: %pD2 cmd=0x%x type=0x%x flags=0x%x r=%lld:%lld\n", __func__, file, cmd,
+		 flock->fl_flags, flock->fl_type, (long long)flock->fl_start,
+		 (long long)flock->fl_end);
+
+	cfile = (struct cifsFileInfo *)file->private_data;
+	tcon = tlink_tcon(cfile->tlink);
+
+	cifs_read_flock(flock, &type, &lock, &unlock, &wait_flag,
+			tcon->ses->server);
+	cifs_sb = CIFS_FILE_SB(file);
+	set_bit(CIFS_INO_CLOSE_ON_LOCK, &CIFS_I(d_inode(cfile->dentry))->flags);
+
+	if (cap_unix(tcon->ses) &&
+	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+		posix_lck = true;
+	/*
+	 * BB add code here to normalize offset and length to account for
+	 * negative length which we can not accept over the wire.
+	 */
+	if (IS_GETLK(cmd)) {
+		rc = cifs_getlk(file, flock, type, wait_flag, posix_lck, xid);
+		free_xid(xid);
+		return rc;
+	}
+
+	if (!lock && !unlock) {
+		/*
+		 * if no lock or unlock then nothing to do since we do not
+		 * know what it is
+		 */
+		free_xid(xid);
+		return -EOPNOTSUPP;
+	}
+
+	rc = cifs_setlk(file, flock, type, wait_flag, posix_lck, lock, unlock,
+			xid);
+	free_xid(xid);
+	return rc;
+}
+
+/*
+ * update the file size (if needed) after a write. Should be called with
+ * the inode->i_lock held
+ */
+void
+cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset,
+		      unsigned int bytes_written)
+{
+	loff_t end_of_write = offset + bytes_written;
+
+	if (end_of_write > cifsi->server_eof)
+		cifsi->server_eof = end_of_write;
+}
+
+static ssize_t
+cifs_write(struct cifsFileInfo *open_file, __u32 pid, const char *write_data,
+	   size_t write_size, loff_t *offset)
+{
+	int rc = 0;
+	unsigned int bytes_written = 0;
+	unsigned int total_written;
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	unsigned int xid;
+	struct dentry *dentry = open_file->dentry;
+	struct cifsInodeInfo *cifsi = CIFS_I(d_inode(dentry));
+	struct cifs_io_parms io_parms = {0};
+
+	cifs_dbg(FYI, "write %zd bytes to offset %lld of %pd\n",
+		 write_size, *offset, dentry);
+
+	tcon = tlink_tcon(open_file->tlink);
+	server = tcon->ses->server;
+
+	if (!server->ops->sync_write)
+		return -ENOSYS;
+
+	xid = get_xid();
+
+	for (total_written = 0; write_size > total_written;
+	     total_written += bytes_written) {
+		rc = -EAGAIN;
+		while (rc == -EAGAIN) {
+			struct kvec iov[2];
+			unsigned int len;
+
+			if (open_file->invalidHandle) {
+				/* we could deadlock if we called
+				   filemap_fdatawait from here so tell
+				   reopen_file not to flush data to
+				   server now */
+				rc = cifs_reopen_file(open_file, false);
+				if (rc != 0)
+					break;
+			}
+
+			len = min(server->ops->wp_retry_size(d_inode(dentry)),
+				  (unsigned int)write_size - total_written);
+			/* iov[0] is reserved for smb header */
+			iov[1].iov_base = (char *)write_data + total_written;
+			iov[1].iov_len = len;
+			io_parms.pid = pid;
+			io_parms.tcon = tcon;
+			io_parms.offset = *offset;
+			io_parms.length = len;
+			rc = server->ops->sync_write(xid, &open_file->fid,
+					&io_parms, &bytes_written, iov, 1);
+		}
+		if (rc || (bytes_written == 0)) {
+			if (total_written)
+				break;
+			else {
+				free_xid(xid);
+				return rc;
+			}
+		} else {
+			spin_lock(&d_inode(dentry)->i_lock);
+			cifs_update_eof(cifsi, *offset, bytes_written);
+			spin_unlock(&d_inode(dentry)->i_lock);
+			*offset += bytes_written;
+		}
+	}
+
+	cifs_stats_bytes_written(tcon, total_written);
+
+	if (total_written > 0) {
+		spin_lock(&d_inode(dentry)->i_lock);
+		if (*offset > d_inode(dentry)->i_size) {
+			i_size_write(d_inode(dentry), *offset);
+			d_inode(dentry)->i_blocks = (512 - 1 + *offset) >> 9;
+		}
+		spin_unlock(&d_inode(dentry)->i_lock);
+	}
+	mark_inode_dirty_sync(d_inode(dentry));
+	free_xid(xid);
+	return total_written;
+}
+
+struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode,
+					bool fsuid_only)
+{
+	struct cifsFileInfo *open_file = NULL;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_inode->netfs.inode.i_sb);
+
+	/* only filter by fsuid on multiuser mounts */
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
+		fsuid_only = false;
+
+	spin_lock(&cifs_inode->open_file_lock);
+	/* we could simply get the first_list_entry since write-only entries
+	   are always at the end of the list but since the first entry might
+	   have a close pending, we go through the whole list */
+	list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
+		if (fsuid_only && !uid_eq(open_file->uid, current_fsuid()))
+			continue;
+		if (OPEN_FMODE(open_file->f_flags) & FMODE_READ) {
+			if ((!open_file->invalidHandle)) {
+				/* found a good file */
+				/* lock it so it will not be closed on us */
+				cifsFileInfo_get(open_file);
+				spin_unlock(&cifs_inode->open_file_lock);
+				return open_file;
+			} /* else might as well continue, and look for
+			     another, or simply have the caller reopen it
+			     again rather than trying to fix this handle */
+		} else /* write only file */
+			break; /* write only files are last so must be done */
+	}
+	spin_unlock(&cifs_inode->open_file_lock);
+	return NULL;
+}
+
+/* Return -EBADF if no handle is found and general rc otherwise */
+int
+cifs_get_writable_file(struct cifsInodeInfo *cifs_inode, int flags,
+		       struct cifsFileInfo **ret_file)
+{
+	struct cifsFileInfo *open_file, *inv_file = NULL;
+	struct cifs_sb_info *cifs_sb;
+	bool any_available = false;
+	int rc = -EBADF;
+	unsigned int refind = 0;
+	bool fsuid_only = flags & FIND_WR_FSUID_ONLY;
+	bool with_delete = flags & FIND_WR_WITH_DELETE;
+	*ret_file = NULL;
+
+	/*
+	 * Having a null inode here (because mapping->host was set to zero by
+	 * the VFS or MM) should not happen but we had reports of on oops (due
+	 * to it being zero) during stress testcases so we need to check for it
+	 */
+
+	if (cifs_inode == NULL) {
+		cifs_dbg(VFS, "Null inode passed to cifs_writeable_file\n");
+		dump_stack();
+		return rc;
+	}
+
+	cifs_sb = CIFS_SB(cifs_inode->netfs.inode.i_sb);
+
+	/* only filter by fsuid on multiuser mounts */
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
+		fsuid_only = false;
+
+	spin_lock(&cifs_inode->open_file_lock);
+refind_writable:
+	if (refind > MAX_REOPEN_ATT) {
+		spin_unlock(&cifs_inode->open_file_lock);
+		return rc;
+	}
+	list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
+		if (!any_available && open_file->pid != current->tgid)
+			continue;
+		if (fsuid_only && !uid_eq(open_file->uid, current_fsuid()))
+			continue;
+		if (with_delete && !(open_file->fid.access & DELETE))
+			continue;
+		if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
+			if (!open_file->invalidHandle) {
+				/* found a good writable file */
+				cifsFileInfo_get(open_file);
+				spin_unlock(&cifs_inode->open_file_lock);
+				*ret_file = open_file;
+				return 0;
+			} else {
+				if (!inv_file)
+					inv_file = open_file;
+			}
+		}
+	}
+	/* couldn't find useable FH with same pid, try any available */
+	if (!any_available) {
+		any_available = true;
+		goto refind_writable;
+	}
+
+	if (inv_file) {
+		any_available = false;
+		cifsFileInfo_get(inv_file);
+	}
+
+	spin_unlock(&cifs_inode->open_file_lock);
+
+	if (inv_file) {
+		rc = cifs_reopen_file(inv_file, false);
+		if (!rc) {
+			*ret_file = inv_file;
+			return 0;
+		}
+
+		spin_lock(&cifs_inode->open_file_lock);
+		list_move_tail(&inv_file->flist, &cifs_inode->openFileList);
+		spin_unlock(&cifs_inode->open_file_lock);
+		cifsFileInfo_put(inv_file);
+		++refind;
+		inv_file = NULL;
+		spin_lock(&cifs_inode->open_file_lock);
+		goto refind_writable;
+	}
+
+	return rc;
+}
+
+struct cifsFileInfo *
+find_writable_file(struct cifsInodeInfo *cifs_inode, int flags)
+{
+	struct cifsFileInfo *cfile;
+	int rc;
+
+	rc = cifs_get_writable_file(cifs_inode, flags, &cfile);
+	if (rc)
+		cifs_dbg(FYI, "Couldn't find writable handle rc=%d\n", rc);
+
+	return cfile;
+}
+
+int
+cifs_get_writable_path(struct cifs_tcon *tcon, const char *name,
+		       int flags,
+		       struct cifsFileInfo **ret_file)
+{
+	struct cifsFileInfo *cfile;
+	void *page = alloc_dentry_path();
+
+	*ret_file = NULL;
+
+	spin_lock(&tcon->open_file_lock);
+	list_for_each_entry(cfile, &tcon->openFileList, tlist) {
+		struct cifsInodeInfo *cinode;
+		const char *full_path = build_path_from_dentry(cfile->dentry, page);
+		if (IS_ERR(full_path)) {
+			spin_unlock(&tcon->open_file_lock);
+			free_dentry_path(page);
+			return PTR_ERR(full_path);
+		}
+		if (strcmp(full_path, name))
+			continue;
+
+		cinode = CIFS_I(d_inode(cfile->dentry));
+		spin_unlock(&tcon->open_file_lock);
+		free_dentry_path(page);
+		return cifs_get_writable_file(cinode, flags, ret_file);
+	}
+
+	spin_unlock(&tcon->open_file_lock);
+	free_dentry_path(page);
+	return -ENOENT;
+}
+
+int
+cifs_get_readable_path(struct cifs_tcon *tcon, const char *name,
+		       struct cifsFileInfo **ret_file)
+{
+	struct cifsFileInfo *cfile;
+	void *page = alloc_dentry_path();
+
+	*ret_file = NULL;
+
+	spin_lock(&tcon->open_file_lock);
+	list_for_each_entry(cfile, &tcon->openFileList, tlist) {
+		struct cifsInodeInfo *cinode;
+		const char *full_path = build_path_from_dentry(cfile->dentry, page);
+		if (IS_ERR(full_path)) {
+			spin_unlock(&tcon->open_file_lock);
+			free_dentry_path(page);
+			return PTR_ERR(full_path);
+		}
+		if (strcmp(full_path, name))
+			continue;
+
+		cinode = CIFS_I(d_inode(cfile->dentry));
+		spin_unlock(&tcon->open_file_lock);
+		free_dentry_path(page);
+		*ret_file = find_readable_file(cinode, 0);
+		return *ret_file ? 0 : -ENOENT;
+	}
+
+	spin_unlock(&tcon->open_file_lock);
+	free_dentry_path(page);
+	return -ENOENT;
+}
+
+void
+cifs_writedata_release(struct kref *refcount)
+{
+	struct cifs_writedata *wdata = container_of(refcount,
+					struct cifs_writedata, refcount);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+	if (wdata->mr) {
+		smbd_deregister_mr(wdata->mr);
+		wdata->mr = NULL;
+	}
+#endif
+
+	if (wdata->cfile)
+		cifsFileInfo_put(wdata->cfile);
+
+	kvfree(wdata->pages);
+	kfree(wdata);
+}
+
+/*
+ * Write failed with a retryable error. Resend the write request. It's also
+ * possible that the page was redirtied so re-clean the page.
+ */
+static void
+cifs_writev_requeue(struct cifs_writedata *wdata)
+{
+	int i, rc = 0;
+	struct inode *inode = d_inode(wdata->cfile->dentry);
+	struct TCP_Server_Info *server;
+	unsigned int rest_len;
+
+	server = tlink_tcon(wdata->cfile->tlink)->ses->server;
+	i = 0;
+	rest_len = wdata->bytes;
+	do {
+		struct cifs_writedata *wdata2;
+		unsigned int j, nr_pages, wsize, tailsz, cur_len;
+
+		wsize = server->ops->wp_retry_size(inode);
+		if (wsize < rest_len) {
+			nr_pages = wsize / PAGE_SIZE;
+			if (!nr_pages) {
+				rc = -EOPNOTSUPP;
+				break;
+			}
+			cur_len = nr_pages * PAGE_SIZE;
+			tailsz = PAGE_SIZE;
+		} else {
+			nr_pages = DIV_ROUND_UP(rest_len, PAGE_SIZE);
+			cur_len = rest_len;
+			tailsz = rest_len - (nr_pages - 1) * PAGE_SIZE;
+		}
+
+		wdata2 = cifs_writedata_alloc(nr_pages, cifs_writev_complete);
+		if (!wdata2) {
+			rc = -ENOMEM;
+			break;
+		}
+
+		for (j = 0; j < nr_pages; j++) {
+			wdata2->pages[j] = wdata->pages[i + j];
+			lock_page(wdata2->pages[j]);
+			clear_page_dirty_for_io(wdata2->pages[j]);
+		}
+
+		wdata2->sync_mode = wdata->sync_mode;
+		wdata2->nr_pages = nr_pages;
+		wdata2->offset = page_offset(wdata2->pages[0]);
+		wdata2->pagesz = PAGE_SIZE;
+		wdata2->tailsz = tailsz;
+		wdata2->bytes = cur_len;
+
+		rc = cifs_get_writable_file(CIFS_I(inode), FIND_WR_ANY,
+					    &wdata2->cfile);
+		if (!wdata2->cfile) {
+			cifs_dbg(VFS, "No writable handle to retry writepages rc=%d\n",
+				 rc);
+			if (!is_retryable_error(rc))
+				rc = -EBADF;
+		} else {
+			wdata2->pid = wdata2->cfile->pid;
+			rc = server->ops->async_writev(wdata2,
+						       cifs_writedata_release);
+		}
+
+		for (j = 0; j < nr_pages; j++) {
+			unlock_page(wdata2->pages[j]);
+			if (rc != 0 && !is_retryable_error(rc)) {
+				SetPageError(wdata2->pages[j]);
+				end_page_writeback(wdata2->pages[j]);
+				put_page(wdata2->pages[j]);
+			}
+		}
+
+		kref_put(&wdata2->refcount, cifs_writedata_release);
+		if (rc) {
+			if (is_retryable_error(rc))
+				continue;
+			i += nr_pages;
+			break;
+		}
+
+		rest_len -= cur_len;
+		i += nr_pages;
+	} while (i < wdata->nr_pages);
+
+	/* cleanup remaining pages from the original wdata */
+	for (; i < wdata->nr_pages; i++) {
+		SetPageError(wdata->pages[i]);
+		end_page_writeback(wdata->pages[i]);
+		put_page(wdata->pages[i]);
+	}
+
+	if (rc != 0 && !is_retryable_error(rc))
+		mapping_set_error(inode->i_mapping, rc);
+	kref_put(&wdata->refcount, cifs_writedata_release);
+}
+
+void
+cifs_writev_complete(struct work_struct *work)
+{
+	struct cifs_writedata *wdata = container_of(work,
+						struct cifs_writedata, work);
+	struct inode *inode = d_inode(wdata->cfile->dentry);
+	int i = 0;
+
+	if (wdata->result == 0) {
+		spin_lock(&inode->i_lock);
+		cifs_update_eof(CIFS_I(inode), wdata->offset, wdata->bytes);
+		spin_unlock(&inode->i_lock);
+		cifs_stats_bytes_written(tlink_tcon(wdata->cfile->tlink),
+					 wdata->bytes);
+	} else if (wdata->sync_mode == WB_SYNC_ALL && wdata->result == -EAGAIN)
+		return cifs_writev_requeue(wdata);
+
+	for (i = 0; i < wdata->nr_pages; i++) {
+		struct page *page = wdata->pages[i];
+
+		if (wdata->result == -EAGAIN)
+			__set_page_dirty_nobuffers(page);
+		else if (wdata->result < 0)
+			SetPageError(page);
+		end_page_writeback(page);
+		cifs_readpage_to_fscache(inode, page);
+		put_page(page);
+	}
+	if (wdata->result != -EAGAIN)
+		mapping_set_error(inode->i_mapping, wdata->result);
+	kref_put(&wdata->refcount, cifs_writedata_release);
+}
+
+struct cifs_writedata *
+cifs_writedata_alloc(unsigned int nr_pages, work_func_t complete)
+{
+	struct cifs_writedata *writedata = NULL;
+	struct page **pages =
+		kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
+	if (pages) {
+		writedata = cifs_writedata_direct_alloc(pages, complete);
+		if (!writedata)
+			kvfree(pages);
+	}
+
+	return writedata;
+}
+
+struct cifs_writedata *
+cifs_writedata_direct_alloc(struct page **pages, work_func_t complete)
+{
+	struct cifs_writedata *wdata;
+
+	wdata = kzalloc(sizeof(*wdata), GFP_NOFS);
+	if (wdata != NULL) {
+		wdata->pages = pages;
+		kref_init(&wdata->refcount);
+		INIT_LIST_HEAD(&wdata->list);
+		init_completion(&wdata->done);
+		INIT_WORK(&wdata->work, complete);
+	}
+	return wdata;
+}
+
+
+static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
+{
+	struct address_space *mapping = page->mapping;
+	loff_t offset = (loff_t)page->index << PAGE_SHIFT;
+	char *write_data;
+	int rc = -EFAULT;
+	int bytes_written = 0;
+	struct inode *inode;
+	struct cifsFileInfo *open_file;
+
+	if (!mapping || !mapping->host)
+		return -EFAULT;
+
+	inode = page->mapping->host;
+
+	offset += (loff_t)from;
+	write_data = kmap(page);
+	write_data += from;
+
+	if ((to > PAGE_SIZE) || (from > to)) {
+		kunmap(page);
+		return -EIO;
+	}
+
+	/* racing with truncate? */
+	if (offset > mapping->host->i_size) {
+		kunmap(page);
+		return 0; /* don't care */
+	}
+
+	/* check to make sure that we are not extending the file */
+	if (mapping->host->i_size - offset < (loff_t)to)
+		to = (unsigned)(mapping->host->i_size - offset);
+
+	rc = cifs_get_writable_file(CIFS_I(mapping->host), FIND_WR_ANY,
+				    &open_file);
+	if (!rc) {
+		bytes_written = cifs_write(open_file, open_file->pid,
+					   write_data, to - from, &offset);
+		cifsFileInfo_put(open_file);
+		/* Does mm or vfs already set times? */
+		inode->i_atime = inode->i_mtime = current_time(inode);
+		if ((bytes_written > 0) && (offset))
+			rc = 0;
+		else if (bytes_written < 0)
+			rc = bytes_written;
+		else
+			rc = -EFAULT;
+	} else {
+		cifs_dbg(FYI, "No writable handle for write page rc=%d\n", rc);
+		if (!is_retryable_error(rc))
+			rc = -EIO;
+	}
+
+	kunmap(page);
+	return rc;
+}
+
+static struct cifs_writedata *
+wdata_alloc_and_fillpages(pgoff_t tofind, struct address_space *mapping,
+			  pgoff_t end, pgoff_t *index,
+			  unsigned int *found_pages)
+{
+	struct cifs_writedata *wdata;
+
+	wdata = cifs_writedata_alloc((unsigned int)tofind,
+				     cifs_writev_complete);
+	if (!wdata)
+		return NULL;
+
+	*found_pages = find_get_pages_range_tag(mapping, index, end,
+				PAGECACHE_TAG_DIRTY, tofind, wdata->pages);
+	return wdata;
+}
+
+static unsigned int
+wdata_prepare_pages(struct cifs_writedata *wdata, unsigned int found_pages,
+		    struct address_space *mapping,
+		    struct writeback_control *wbc,
+		    pgoff_t end, pgoff_t *index, pgoff_t *next, bool *done)
+{
+	unsigned int nr_pages = 0, i;
+	struct page *page;
+
+	for (i = 0; i < found_pages; i++) {
+		page = wdata->pages[i];
+		/*
+		 * At this point we hold neither the i_pages lock nor the
+		 * page lock: the page may be truncated or invalidated
+		 * (changing page->mapping to NULL), or even swizzled
+		 * back from swapper_space to tmpfs file mapping
+		 */
+
+		if (nr_pages == 0)
+			lock_page(page);
+		else if (!trylock_page(page))
+			break;
+
+		if (unlikely(page->mapping != mapping)) {
+			unlock_page(page);
+			break;
+		}
+
+		if (!wbc->range_cyclic && page->index > end) {
+			*done = true;
+			unlock_page(page);
+			break;
+		}
+
+		if (*next && (page->index != *next)) {
+			/* Not next consecutive page */
+			unlock_page(page);
+			break;
+		}
+
+		if (wbc->sync_mode != WB_SYNC_NONE)
+			wait_on_page_writeback(page);
+
+		if (PageWriteback(page) ||
+				!clear_page_dirty_for_io(page)) {
+			unlock_page(page);
+			break;
+		}
+
+		/*
+		 * This actually clears the dirty bit in the radix tree.
+		 * See cifs_writepage() for more commentary.
+		 */
+		set_page_writeback(page);
+		if (page_offset(page) >= i_size_read(mapping->host)) {
+			*done = true;
+			unlock_page(page);
+			end_page_writeback(page);
+			break;
+		}
+
+		wdata->pages[i] = page;
+		*next = page->index + 1;
+		++nr_pages;
+	}
+
+	/* reset index to refind any pages skipped */
+	if (nr_pages == 0)
+		*index = wdata->pages[0]->index + 1;
+
+	/* put any pages we aren't going to use */
+	for (i = nr_pages; i < found_pages; i++) {
+		put_page(wdata->pages[i]);
+		wdata->pages[i] = NULL;
+	}
+
+	return nr_pages;
+}
+
+static int
+wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
+		 struct address_space *mapping, struct writeback_control *wbc)
+{
+	int rc;
+
+	wdata->sync_mode = wbc->sync_mode;
+	wdata->nr_pages = nr_pages;
+	wdata->offset = page_offset(wdata->pages[0]);
+	wdata->pagesz = PAGE_SIZE;
+	wdata->tailsz = min(i_size_read(mapping->host) -
+			page_offset(wdata->pages[nr_pages - 1]),
+			(loff_t)PAGE_SIZE);
+	wdata->bytes = ((nr_pages - 1) * PAGE_SIZE) + wdata->tailsz;
+	wdata->pid = wdata->cfile->pid;
+
+	rc = adjust_credits(wdata->server, &wdata->credits, wdata->bytes);
+	if (rc)
+		return rc;
+
+	if (wdata->cfile->invalidHandle)
+		rc = -EAGAIN;
+	else
+		rc = wdata->server->ops->async_writev(wdata,
+						      cifs_writedata_release);
+
+	return rc;
+}
+
+static int cifs_writepages(struct address_space *mapping,
+			   struct writeback_control *wbc)
+{
+	struct inode *inode = mapping->host;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct TCP_Server_Info *server;
+	bool done = false, scanned = false, range_whole = false;
+	pgoff_t end, index;
+	struct cifs_writedata *wdata;
+	struct cifsFileInfo *cfile = NULL;
+	int rc = 0;
+	int saved_rc = 0;
+	unsigned int xid;
+
+	/*
+	 * If wsize is smaller than the page cache size, default to writing
+	 * one page at a time via cifs_writepage
+	 */
+	if (cifs_sb->ctx->wsize < PAGE_SIZE)
+		return generic_writepages(mapping, wbc);
+
+	xid = get_xid();
+	if (wbc->range_cyclic) {
+		index = mapping->writeback_index; /* Start from prev offset */
+		end = -1;
+	} else {
+		index = wbc->range_start >> PAGE_SHIFT;
+		end = wbc->range_end >> PAGE_SHIFT;
+		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+			range_whole = true;
+		scanned = true;
+	}
+	server = cifs_pick_channel(cifs_sb_master_tcon(cifs_sb)->ses);
+
+retry:
+	while (!done && index <= end) {
+		unsigned int i, nr_pages, found_pages, wsize;
+		pgoff_t next = 0, tofind, saved_index = index;
+		struct cifs_credits credits_on_stack;
+		struct cifs_credits *credits = &credits_on_stack;
+		int get_file_rc = 0;
+
+		if (cfile)
+			cifsFileInfo_put(cfile);
+
+		rc = cifs_get_writable_file(CIFS_I(inode), FIND_WR_ANY, &cfile);
+
+		/* in case of an error store it to return later */
+		if (rc)
+			get_file_rc = rc;
+
+		rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->wsize,
+						   &wsize, credits);
+		if (rc != 0) {
+			done = true;
+			break;
+		}
+
+		tofind = min((wsize / PAGE_SIZE) - 1, end - index) + 1;
+
+		wdata = wdata_alloc_and_fillpages(tofind, mapping, end, &index,
+						  &found_pages);
+		if (!wdata) {
+			rc = -ENOMEM;
+			done = true;
+			add_credits_and_wake_if(server, credits, 0);
+			break;
+		}
+
+		if (found_pages == 0) {
+			kref_put(&wdata->refcount, cifs_writedata_release);
+			add_credits_and_wake_if(server, credits, 0);
+			break;
+		}
+
+		nr_pages = wdata_prepare_pages(wdata, found_pages, mapping, wbc,
+					       end, &index, &next, &done);
+
+		/* nothing to write? */
+		if (nr_pages == 0) {
+			kref_put(&wdata->refcount, cifs_writedata_release);
+			add_credits_and_wake_if(server, credits, 0);
+			continue;
+		}
+
+		wdata->credits = credits_on_stack;
+		wdata->cfile = cfile;
+		wdata->server = server;
+		cfile = NULL;
+
+		if (!wdata->cfile) {
+			cifs_dbg(VFS, "No writable handle in writepages rc=%d\n",
+				 get_file_rc);
+			if (is_retryable_error(get_file_rc))
+				rc = get_file_rc;
+			else
+				rc = -EBADF;
+		} else
+			rc = wdata_send_pages(wdata, nr_pages, mapping, wbc);
+
+		for (i = 0; i < nr_pages; ++i)
+			unlock_page(wdata->pages[i]);
+
+		/* send failure -- clean up the mess */
+		if (rc != 0) {
+			add_credits_and_wake_if(server, &wdata->credits, 0);
+			for (i = 0; i < nr_pages; ++i) {
+				if (is_retryable_error(rc))
+					redirty_page_for_writepage(wbc,
+							   wdata->pages[i]);
+				else
+					SetPageError(wdata->pages[i]);
+				end_page_writeback(wdata->pages[i]);
+				put_page(wdata->pages[i]);
+			}
+			if (!is_retryable_error(rc))
+				mapping_set_error(mapping, rc);
+		}
+		kref_put(&wdata->refcount, cifs_writedata_release);
+
+		if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN) {
+			index = saved_index;
+			continue;
+		}
+
+		/* Return immediately if we received a signal during writing */
+		if (is_interrupt_error(rc)) {
+			done = true;
+			break;
+		}
+
+		if (rc != 0 && saved_rc == 0)
+			saved_rc = rc;
+
+		wbc->nr_to_write -= nr_pages;
+		if (wbc->nr_to_write <= 0)
+			done = true;
+
+		index = next;
+	}
+
+	if (!scanned && !done) {
+		/*
+		 * We hit the last page and there is more work to be done: wrap
+		 * back to the start of the file
+		 */
+		scanned = true;
+		index = 0;
+		goto retry;
+	}
+
+	if (saved_rc != 0)
+		rc = saved_rc;
+
+	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+		mapping->writeback_index = index;
+
+	if (cfile)
+		cifsFileInfo_put(cfile);
+	free_xid(xid);
+	/* Indication to update ctime and mtime as close is deferred */
+	set_bit(CIFS_INO_MODIFIED_ATTR, &CIFS_I(inode)->flags);
+	return rc;
+}
+
+static int
+cifs_writepage_locked(struct page *page, struct writeback_control *wbc)
+{
+	int rc;
+	unsigned int xid;
+
+	xid = get_xid();
+/* BB add check for wbc flags */
+	get_page(page);
+	if (!PageUptodate(page))
+		cifs_dbg(FYI, "ppw - page not up to date\n");
+
+	/*
+	 * Set the "writeback" flag, and clear "dirty" in the radix tree.
+	 *
+	 * A writepage() implementation always needs to do either this,
+	 * or re-dirty the page with "redirty_page_for_writepage()" in
+	 * the case of a failure.
+	 *
+	 * Just unlocking the page will cause the radix tree tag-bits
+	 * to fail to update with the state of the page correctly.
+	 */
+	set_page_writeback(page);
+retry_write:
+	rc = cifs_partialpagewrite(page, 0, PAGE_SIZE);
+	if (is_retryable_error(rc)) {
+		if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN)
+			goto retry_write;
+		redirty_page_for_writepage(wbc, page);
+	} else if (rc != 0) {
+		SetPageError(page);
+		mapping_set_error(page->mapping, rc);
+	} else {
+		SetPageUptodate(page);
+	}
+	end_page_writeback(page);
+	put_page(page);
+	free_xid(xid);
+	return rc;
+}
+
+static int cifs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	int rc = cifs_writepage_locked(page, wbc);
+	unlock_page(page);
+	return rc;
+}
+
+static int cifs_write_end(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
+{
+	int rc;
+	struct inode *inode = mapping->host;
+	struct cifsFileInfo *cfile = file->private_data;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
+	__u32 pid;
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
+		pid = cfile->pid;
+	else
+		pid = current->tgid;
+
+	cifs_dbg(FYI, "write_end for page %p from pos %lld with %d bytes\n",
+		 page, pos, copied);
+
+	if (PageChecked(page)) {
+		if (copied == len)
+			SetPageUptodate(page);
+		ClearPageChecked(page);
+	} else if (!PageUptodate(page) && copied == PAGE_SIZE)
+		SetPageUptodate(page);
+
+	if (!PageUptodate(page)) {
+		char *page_data;
+		unsigned offset = pos & (PAGE_SIZE - 1);
+		unsigned int xid;
+
+		xid = get_xid();
+		/* this is probably better than directly calling
+		   partialpage_write since in this function the file handle is
+		   known which we might as well	leverage */
+		/* BB check if anything else missing out of ppw
+		   such as updating last write time */
+		page_data = kmap(page);
+		rc = cifs_write(cfile, pid, page_data + offset, copied, &pos);
+		/* if (rc < 0) should we set writebehind rc? */
+		kunmap(page);
+
+		free_xid(xid);
+	} else {
+		rc = copied;
+		pos += copied;
+		set_page_dirty(page);
+	}
+
+	if (rc > 0) {
+		spin_lock(&inode->i_lock);
+		if (pos > inode->i_size) {
+			i_size_write(inode, pos);
+			inode->i_blocks = (512 - 1 + pos) >> 9;
+		}
+		spin_unlock(&inode->i_lock);
+	}
+
+	unlock_page(page);
+	put_page(page);
+	/* Indication to update ctime and mtime as close is deferred */
+	set_bit(CIFS_INO_MODIFIED_ATTR, &CIFS_I(inode)->flags);
+
+	return rc;
+}
+
+int cifs_strict_fsync(struct file *file, loff_t start, loff_t end,
+		      int datasync)
+{
+	unsigned int xid;
+	int rc = 0;
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	struct cifsFileInfo *smbfile = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+
+	rc = file_write_and_wait_range(file, start, end);
+	if (rc) {
+		trace_cifs_fsync_err(inode->i_ino, rc);
+		return rc;
+	}
+
+	xid = get_xid();
+
+	cifs_dbg(FYI, "Sync file - name: %pD datasync: 0x%x\n",
+		 file, datasync);
+
+	if (!CIFS_CACHE_READ(CIFS_I(inode))) {
+		rc = cifs_zap_mapping(inode);
+		if (rc) {
+			cifs_dbg(FYI, "rc: %d during invalidate phase\n", rc);
+			rc = 0; /* don't care about it in fsync */
+		}
+	}
+
+	tcon = tlink_tcon(smbfile->tlink);
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
+		server = tcon->ses->server;
+		if (server->ops->flush == NULL) {
+			rc = -ENOSYS;
+			goto strict_fsync_exit;
+		}
+
+		if ((OPEN_FMODE(smbfile->f_flags) & FMODE_WRITE) == 0) {
+			smbfile = find_writable_file(CIFS_I(inode), FIND_WR_ANY);
+			if (smbfile) {
+				rc = server->ops->flush(xid, tcon, &smbfile->fid);
+				cifsFileInfo_put(smbfile);
+			} else
+				cifs_dbg(FYI, "ignore fsync for file not open for write\n");
+		} else
+			rc = server->ops->flush(xid, tcon, &smbfile->fid);
+	}
+
+strict_fsync_exit:
+	free_xid(xid);
+	return rc;
+}
+
+int cifs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	unsigned int xid;
+	int rc = 0;
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	struct cifsFileInfo *smbfile = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
+
+	rc = file_write_and_wait_range(file, start, end);
+	if (rc) {
+		trace_cifs_fsync_err(file_inode(file)->i_ino, rc);
+		return rc;
+	}
+
+	xid = get_xid();
+
+	cifs_dbg(FYI, "Sync file - name: %pD datasync: 0x%x\n",
+		 file, datasync);
+
+	tcon = tlink_tcon(smbfile->tlink);
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOSSYNC)) {
+		server = tcon->ses->server;
+		if (server->ops->flush == NULL) {
+			rc = -ENOSYS;
+			goto fsync_exit;
+		}
+
+		if ((OPEN_FMODE(smbfile->f_flags) & FMODE_WRITE) == 0) {
+			smbfile = find_writable_file(CIFS_I(inode), FIND_WR_ANY);
+			if (smbfile) {
+				rc = server->ops->flush(xid, tcon, &smbfile->fid);
+				cifsFileInfo_put(smbfile);
+			} else
+				cifs_dbg(FYI, "ignore fsync for file not open for write\n");
+		} else
+			rc = server->ops->flush(xid, tcon, &smbfile->fid);
+	}
+
+fsync_exit:
+	free_xid(xid);
+	return rc;
+}
+
+/*
+ * As file closes, flush all cached write data for this inode checking
+ * for write behind errors.
+ */
+int cifs_flush(struct file *file, fl_owner_t id)
+{
+	struct inode *inode = file_inode(file);
+	int rc = 0;
+
+	if (file->f_mode & FMODE_WRITE)
+		rc = filemap_write_and_wait(inode->i_mapping);
+
+	cifs_dbg(FYI, "Flush inode %p file %p rc %d\n", inode, file, rc);
+	if (rc) {
+		/* get more nuanced writeback errors */
+		rc = filemap_check_wb_err(file->f_mapping, 0);
+		trace_cifs_flush_err(inode->i_ino, rc);
+	}
+	return rc;
+}
+
+static int
+cifs_write_allocate_pages(struct page **pages, unsigned long num_pages)
+{
+	int rc = 0;
+	unsigned long i;
+
+	for (i = 0; i < num_pages; i++) {
+		pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
+		if (!pages[i]) {
+			/*
+			 * save number of pages we have already allocated and
+			 * return with ENOMEM error
+			 */
+			num_pages = i;
+			rc = -ENOMEM;
+			break;
+		}
+	}
+
+	if (rc) {
+		for (i = 0; i < num_pages; i++)
+			put_page(pages[i]);
+	}
+	return rc;
+}
+
+static inline
+size_t get_numpages(const size_t wsize, const size_t len, size_t *cur_len)
+{
+	size_t num_pages;
+	size_t clen;
+
+	clen = min_t(const size_t, len, wsize);
+	num_pages = DIV_ROUND_UP(clen, PAGE_SIZE);
+
+	if (cur_len)
+		*cur_len = clen;
+
+	return num_pages;
+}
+
+static void
+cifs_uncached_writedata_release(struct kref *refcount)
+{
+	int i;
+	struct cifs_writedata *wdata = container_of(refcount,
+					struct cifs_writedata, refcount);
+
+	kref_put(&wdata->ctx->refcount, cifs_aio_ctx_release);
+	for (i = 0; i < wdata->nr_pages; i++)
+		put_page(wdata->pages[i]);
+	cifs_writedata_release(refcount);
+}
+
+static void collect_uncached_write_data(struct cifs_aio_ctx *ctx);
+
+static void
+cifs_uncached_writev_complete(struct work_struct *work)
+{
+	struct cifs_writedata *wdata = container_of(work,
+					struct cifs_writedata, work);
+	struct inode *inode = d_inode(wdata->cfile->dentry);
+	struct cifsInodeInfo *cifsi = CIFS_I(inode);
+
+	spin_lock(&inode->i_lock);
+	cifs_update_eof(cifsi, wdata->offset, wdata->bytes);
+	if (cifsi->server_eof > inode->i_size)
+		i_size_write(inode, cifsi->server_eof);
+	spin_unlock(&inode->i_lock);
+
+	complete(&wdata->done);
+	collect_uncached_write_data(wdata->ctx);
+	/* the below call can possibly free the last ref to aio ctx */
+	kref_put(&wdata->refcount, cifs_uncached_writedata_release);
+}
+
+static int
+wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
+		      size_t *len, unsigned long *num_pages)
+{
+	size_t save_len, copied, bytes, cur_len = *len;
+	unsigned long i, nr_pages = *num_pages;
+
+	save_len = cur_len;
+	for (i = 0; i < nr_pages; i++) {
+		bytes = min_t(const size_t, cur_len, PAGE_SIZE);
+		copied = copy_page_from_iter(wdata->pages[i], 0, bytes, from);
+		cur_len -= copied;
+		/*
+		 * If we didn't copy as much as we expected, then that
+		 * may mean we trod into an unmapped area. Stop copying
+		 * at that point. On the next pass through the big
+		 * loop, we'll likely end up getting a zero-length
+		 * write and bailing out of it.
+		 */
+		if (copied < bytes)
+			break;
+	}
+	cur_len = save_len - cur_len;
+	*len = cur_len;
+
+	/*
+	 * If we have no data to send, then that probably means that
+	 * the copy above failed altogether. That's most likely because
+	 * the address in the iovec was bogus. Return -EFAULT and let
+	 * the caller free anything we allocated and bail out.
+	 */
+	if (!cur_len)
+		return -EFAULT;
+
+	/*
+	 * i + 1 now represents the number of pages we actually used in
+	 * the copy phase above.
+	 */
+	*num_pages = i + 1;
+	return 0;
+}
+
+static int
+cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
+	struct cifs_aio_ctx *ctx)
+{
+	unsigned int wsize;
+	struct cifs_credits credits;
+	int rc;
+	struct TCP_Server_Info *server = wdata->server;
+
+	do {
+		if (wdata->cfile->invalidHandle) {
+			rc = cifs_reopen_file(wdata->cfile, false);
+			if (rc == -EAGAIN)
+				continue;
+			else if (rc)
+				break;
+		}
+
+
+		/*
+		 * Wait for credits to resend this wdata.
+		 * Note: we are attempting to resend the whole wdata not in
+		 * segments
+		 */
+		do {
+			rc = server->ops->wait_mtu_credits(server, wdata->bytes,
+						&wsize, &credits);
+			if (rc)
+				goto fail;
+
+			if (wsize < wdata->bytes) {
+				add_credits_and_wake_if(server, &credits, 0);
+				msleep(1000);
+			}
+		} while (wsize < wdata->bytes);
+		wdata->credits = credits;
+
+		rc = adjust_credits(server, &wdata->credits, wdata->bytes);
+
+		if (!rc) {
+			if (wdata->cfile->invalidHandle)
+				rc = -EAGAIN;
+			else {
+#ifdef CONFIG_CIFS_SMB_DIRECT
+				if (wdata->mr) {
+					wdata->mr->need_invalidate = true;
+					smbd_deregister_mr(wdata->mr);
+					wdata->mr = NULL;
+				}
+#endif
+				rc = server->ops->async_writev(wdata,
+					cifs_uncached_writedata_release);
+			}
+		}
+
+		/* If the write was successfully sent, we are done */
+		if (!rc) {
+			list_add_tail(&wdata->list, wdata_list);
+			return 0;
+		}
+
+		/* Roll back credits and retry if needed */
+		add_credits_and_wake_if(server, &wdata->credits, 0);
+	} while (rc == -EAGAIN);
+
+fail:
+	kref_put(&wdata->refcount, cifs_uncached_writedata_release);
+	return rc;
+}
+
+static int
+cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
+		     struct cifsFileInfo *open_file,
+		     struct cifs_sb_info *cifs_sb, struct list_head *wdata_list,
+		     struct cifs_aio_ctx *ctx)
+{
+	int rc = 0;
+	size_t cur_len;
+	unsigned long nr_pages, num_pages, i;
+	struct cifs_writedata *wdata;
+	struct iov_iter saved_from = *from;
+	loff_t saved_offset = offset;
+	pid_t pid;
+	struct TCP_Server_Info *server;
+	struct page **pagevec;
+	size_t start;
+	unsigned int xid;
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
+		pid = open_file->pid;
+	else
+		pid = current->tgid;
+
+	server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
+	xid = get_xid();
+
+	do {
+		unsigned int wsize;
+		struct cifs_credits credits_on_stack;
+		struct cifs_credits *credits = &credits_on_stack;
+
+		if (open_file->invalidHandle) {
+			rc = cifs_reopen_file(open_file, false);
+			if (rc == -EAGAIN)
+				continue;
+			else if (rc)
+				break;
+		}
+
+		rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->wsize,
+						   &wsize, credits);
+		if (rc)
+			break;
+
+		cur_len = min_t(const size_t, len, wsize);
+
+		if (ctx->direct_io) {
+			ssize_t result;
+
+			result = iov_iter_get_pages_alloc2(
+				from, &pagevec, cur_len, &start);
+			if (result < 0) {
+				cifs_dbg(VFS,
+					 "direct_writev couldn't get user pages (rc=%zd) iter type %d iov_offset %zd count %zd\n",
+					 result, iov_iter_type(from),
+					 from->iov_offset, from->count);
+				dump_stack();
+
+				rc = result;
+				add_credits_and_wake_if(server, credits, 0);
+				break;
+			}
+			cur_len = (size_t)result;
+
+			nr_pages =
+				(cur_len + start + PAGE_SIZE - 1) / PAGE_SIZE;
+
+			wdata = cifs_writedata_direct_alloc(pagevec,
+					     cifs_uncached_writev_complete);
+			if (!wdata) {
+				rc = -ENOMEM;
+				for (i = 0; i < nr_pages; i++)
+					put_page(pagevec[i]);
+				kvfree(pagevec);
+				add_credits_and_wake_if(server, credits, 0);
+				break;
+			}
+
+
+			wdata->page_offset = start;
+			wdata->tailsz =
+				nr_pages > 1 ?
+					cur_len - (PAGE_SIZE - start) -
+					(nr_pages - 2) * PAGE_SIZE :
+					cur_len;
+		} else {
+			nr_pages = get_numpages(wsize, len, &cur_len);
+			wdata = cifs_writedata_alloc(nr_pages,
+					     cifs_uncached_writev_complete);
+			if (!wdata) {
+				rc = -ENOMEM;
+				add_credits_and_wake_if(server, credits, 0);
+				break;
+			}
+
+			rc = cifs_write_allocate_pages(wdata->pages, nr_pages);
+			if (rc) {
+				kvfree(wdata->pages);
+				kfree(wdata);
+				add_credits_and_wake_if(server, credits, 0);
+				break;
+			}
+
+			num_pages = nr_pages;
+			rc = wdata_fill_from_iovec(
+				wdata, from, &cur_len, &num_pages);
+			if (rc) {
+				for (i = 0; i < nr_pages; i++)
+					put_page(wdata->pages[i]);
+				kvfree(wdata->pages);
+				kfree(wdata);
+				add_credits_and_wake_if(server, credits, 0);
+				break;
+			}
+
+			/*
+			 * Bring nr_pages down to the number of pages we
+			 * actually used, and free any pages that we didn't use.
+			 */
+			for ( ; nr_pages > num_pages; nr_pages--)
+				put_page(wdata->pages[nr_pages - 1]);
+
+			wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
+		}
+
+		wdata->sync_mode = WB_SYNC_ALL;
+		wdata->nr_pages = nr_pages;
+		wdata->offset = (__u64)offset;
+		wdata->cfile = cifsFileInfo_get(open_file);
+		wdata->server = server;
+		wdata->pid = pid;
+		wdata->bytes = cur_len;
+		wdata->pagesz = PAGE_SIZE;
+		wdata->credits = credits_on_stack;
+		wdata->ctx = ctx;
+		kref_get(&ctx->refcount);
+
+		rc = adjust_credits(server, &wdata->credits, wdata->bytes);
+
+		if (!rc) {
+			if (wdata->cfile->invalidHandle)
+				rc = -EAGAIN;
+			else
+				rc = server->ops->async_writev(wdata,
+					cifs_uncached_writedata_release);
+		}
+
+		if (rc) {
+			add_credits_and_wake_if(server, &wdata->credits, 0);
+			kref_put(&wdata->refcount,
+				 cifs_uncached_writedata_release);
+			if (rc == -EAGAIN) {
+				*from = saved_from;
+				iov_iter_advance(from, offset - saved_offset);
+				continue;
+			}
+			break;
+		}
+
+		list_add_tail(&wdata->list, wdata_list);
+		offset += cur_len;
+		len -= cur_len;
+	} while (len > 0);
+
+	free_xid(xid);
+	return rc;
+}
+
+static void collect_uncached_write_data(struct cifs_aio_ctx *ctx)
+{
+	struct cifs_writedata *wdata, *tmp;
+	struct cifs_tcon *tcon;
+	struct cifs_sb_info *cifs_sb;
+	struct dentry *dentry = ctx->cfile->dentry;
+	ssize_t rc;
+
+	tcon = tlink_tcon(ctx->cfile->tlink);
+	cifs_sb = CIFS_SB(dentry->d_sb);
+
+	mutex_lock(&ctx->aio_mutex);
+
+	if (list_empty(&ctx->list)) {
+		mutex_unlock(&ctx->aio_mutex);
+		return;
+	}
+
+	rc = ctx->rc;
+	/*
+	 * Wait for and collect replies for any successful sends in order of
+	 * increasing offset. Once an error is hit, then return without waiting
+	 * for any more replies.
+	 */
+restart_loop:
+	list_for_each_entry_safe(wdata, tmp, &ctx->list, list) {
+		if (!rc) {
+			if (!try_wait_for_completion(&wdata->done)) {
+				mutex_unlock(&ctx->aio_mutex);
+				return;
+			}
+
+			if (wdata->result)
+				rc = wdata->result;
+			else
+				ctx->total_len += wdata->bytes;
+
+			/* resend call if it's a retryable error */
+			if (rc == -EAGAIN) {
+				struct list_head tmp_list;
+				struct iov_iter tmp_from = ctx->iter;
+
+				INIT_LIST_HEAD(&tmp_list);
+				list_del_init(&wdata->list);
+
+				if (ctx->direct_io)
+					rc = cifs_resend_wdata(
+						wdata, &tmp_list, ctx);
+				else {
+					iov_iter_advance(&tmp_from,
+						 wdata->offset - ctx->pos);
+
+					rc = cifs_write_from_iter(wdata->offset,
+						wdata->bytes, &tmp_from,
+						ctx->cfile, cifs_sb, &tmp_list,
+						ctx);
+
+					kref_put(&wdata->refcount,
+						cifs_uncached_writedata_release);
+				}
+
+				list_splice(&tmp_list, &ctx->list);
+				goto restart_loop;
+			}
+		}
+		list_del_init(&wdata->list);
+		kref_put(&wdata->refcount, cifs_uncached_writedata_release);
+	}
+
+	cifs_stats_bytes_written(tcon, ctx->total_len);
+	set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(dentry->d_inode)->flags);
+
+	ctx->rc = (rc == 0) ? ctx->total_len : rc;
+
+	mutex_unlock(&ctx->aio_mutex);
+
+	if (ctx->iocb && ctx->iocb->ki_complete)
+		ctx->iocb->ki_complete(ctx->iocb, ctx->rc);
+	else
+		complete(&ctx->done);
+}
+
+static ssize_t __cifs_writev(
+	struct kiocb *iocb, struct iov_iter *from, bool direct)
+{
+	struct file *file = iocb->ki_filp;
+	ssize_t total_written = 0;
+	struct cifsFileInfo *cfile;
+	struct cifs_tcon *tcon;
+	struct cifs_sb_info *cifs_sb;
+	struct cifs_aio_ctx *ctx;
+	struct iov_iter saved_from = *from;
+	size_t len = iov_iter_count(from);
+	int rc;
+
+	/*
+	 * iov_iter_get_pages_alloc doesn't work with ITER_KVEC.
+	 * In this case, fall back to non-direct write function.
+	 * this could be improved by getting pages directly in ITER_KVEC
+	 */
+	if (direct && iov_iter_is_kvec(from)) {
+		cifs_dbg(FYI, "use non-direct cifs_writev for kvec I/O\n");
+		direct = false;
+	}
+
+	rc = generic_write_checks(iocb, from);
+	if (rc <= 0)
+		return rc;
+
+	cifs_sb = CIFS_FILE_SB(file);
+	cfile = file->private_data;
+	tcon = tlink_tcon(cfile->tlink);
+
+	if (!tcon->ses->server->ops->async_writev)
+		return -ENOSYS;
+
+	ctx = cifs_aio_ctx_alloc();
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->cfile = cifsFileInfo_get(cfile);
+
+	if (!is_sync_kiocb(iocb))
+		ctx->iocb = iocb;
+
+	ctx->pos = iocb->ki_pos;
+
+	if (direct) {
+		ctx->direct_io = true;
+		ctx->iter = *from;
+		ctx->len = len;
+	} else {
+		rc = setup_aio_ctx_iter(ctx, from, ITER_SOURCE);
+		if (rc) {
+			kref_put(&ctx->refcount, cifs_aio_ctx_release);
+			return rc;
+		}
+	}
+
+	/* grab a lock here due to read response handlers can access ctx */
+	mutex_lock(&ctx->aio_mutex);
+
+	rc = cifs_write_from_iter(iocb->ki_pos, ctx->len, &saved_from,
+				  cfile, cifs_sb, &ctx->list, ctx);
+
+	/*
+	 * If at least one write was successfully sent, then discard any rc
+	 * value from the later writes. If the other write succeeds, then
+	 * we'll end up returning whatever was written. If it fails, then
+	 * we'll get a new rc value from that.
+	 */
+	if (!list_empty(&ctx->list))
+		rc = 0;
+
+	mutex_unlock(&ctx->aio_mutex);
+
+	if (rc) {
+		kref_put(&ctx->refcount, cifs_aio_ctx_release);
+		return rc;
+	}
+
+	if (!is_sync_kiocb(iocb)) {
+		kref_put(&ctx->refcount, cifs_aio_ctx_release);
+		return -EIOCBQUEUED;
+	}
+
+	rc = wait_for_completion_killable(&ctx->done);
+	if (rc) {
+		mutex_lock(&ctx->aio_mutex);
+		ctx->rc = rc = -EINTR;
+		total_written = ctx->total_len;
+		mutex_unlock(&ctx->aio_mutex);
+	} else {
+		rc = ctx->rc;
+		total_written = ctx->total_len;
+	}
+
+	kref_put(&ctx->refcount, cifs_aio_ctx_release);
+
+	if (unlikely(!total_written))
+		return rc;
+
+	iocb->ki_pos += total_written;
+	return total_written;
+}
+
+ssize_t cifs_direct_writev(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+
+	cifs_revalidate_mapping(file->f_inode);
+	return __cifs_writev(iocb, from, true);
+}
+
+ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
+{
+	return __cifs_writev(iocb, from, false);
+}
+
+static ssize_t
+cifs_writev(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
+	struct inode *inode = file->f_mapping->host;
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
+	ssize_t rc;
+
+	inode_lock(inode);
+	/*
+	 * We need to hold the sem to be sure nobody modifies lock list
+	 * with a brlock that prevents writing.
+	 */
+	down_read(&cinode->lock_sem);
+
+	rc = generic_write_checks(iocb, from);
+	if (rc <= 0)
+		goto out;
+
+	if (!cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(from),
+				     server->vals->exclusive_lock_type, 0,
+				     NULL, CIFS_WRITE_OP))
+		rc = __generic_file_write_iter(iocb, from);
+	else
+		rc = -EACCES;
+out:
+	up_read(&cinode->lock_sem);
+	inode_unlock(inode);
+
+	if (rc > 0)
+		rc = generic_write_sync(iocb, rc);
+	return rc;
+}
+
+ssize_t
+cifs_strict_writev(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifsFileInfo *cfile = (struct cifsFileInfo *)
+						iocb->ki_filp->private_data;
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	ssize_t written;
+
+	written = cifs_get_writer(cinode);
+	if (written)
+		return written;
+
+	if (CIFS_CACHE_WRITE(cinode)) {
+		if (cap_unix(tcon->ses) &&
+		(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability))
+		  && ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0)) {
+			written = generic_file_write_iter(iocb, from);
+			goto out;
+		}
+		written = cifs_writev(iocb, from);
+		goto out;
+	}
+	/*
+	 * For non-oplocked files in strict cache mode we need to write the data
+	 * to the server exactly from the pos to pos+len-1 rather than flush all
+	 * affected pages because it may cause a error with mandatory locks on
+	 * these pages but not on the region from pos to ppos+len-1.
+	 */
+	written = cifs_user_writev(iocb, from);
+	if (CIFS_CACHE_READ(cinode)) {
+		/*
+		 * We have read level caching and we have just sent a write
+		 * request to the server thus making data in the cache stale.
+		 * Zap the cache and set oplock/lease level to NONE to avoid
+		 * reading stale data from the cache. All subsequent read
+		 * operations will read new data from the server.
+		 */
+		cifs_zap_mapping(inode);
+		cifs_dbg(FYI, "Set Oplock/Lease to NONE for inode=%p after write\n",
+			 inode);
+		cinode->oplock = 0;
+	}
+out:
+	cifs_put_writer(cinode);
+	return written;
+}
+
+static struct cifs_readdata *
+cifs_readdata_direct_alloc(struct page **pages, work_func_t complete)
+{
+	struct cifs_readdata *rdata;
+
+	rdata = kzalloc(sizeof(*rdata), GFP_KERNEL);
+	if (rdata != NULL) {
+		rdata->pages = pages;
+		kref_init(&rdata->refcount);
+		INIT_LIST_HEAD(&rdata->list);
+		init_completion(&rdata->done);
+		INIT_WORK(&rdata->work, complete);
+	}
+
+	return rdata;
+}
+
+static struct cifs_readdata *
+cifs_readdata_alloc(unsigned int nr_pages, work_func_t complete)
+{
+	struct page **pages =
+		kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
+	struct cifs_readdata *ret = NULL;
+
+	if (pages) {
+		ret = cifs_readdata_direct_alloc(pages, complete);
+		if (!ret)
+			kfree(pages);
+	}
+
+	return ret;
+}
+
+void
+cifs_readdata_release(struct kref *refcount)
+{
+	struct cifs_readdata *rdata = container_of(refcount,
+					struct cifs_readdata, refcount);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+	if (rdata->mr) {
+		smbd_deregister_mr(rdata->mr);
+		rdata->mr = NULL;
+	}
+#endif
+	if (rdata->cfile)
+		cifsFileInfo_put(rdata->cfile);
+
+	kvfree(rdata->pages);
+	kfree(rdata);
+}
+
+static int
+cifs_read_allocate_pages(struct cifs_readdata *rdata, unsigned int nr_pages)
+{
+	int rc = 0;
+	struct page *page;
+	unsigned int i;
+
+	for (i = 0; i < nr_pages; i++) {
+		page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
+		if (!page) {
+			rc = -ENOMEM;
+			break;
+		}
+		rdata->pages[i] = page;
+	}
+
+	if (rc) {
+		unsigned int nr_page_failed = i;
+
+		for (i = 0; i < nr_page_failed; i++) {
+			put_page(rdata->pages[i]);
+			rdata->pages[i] = NULL;
+		}
+	}
+	return rc;
+}
+
+static void
+cifs_uncached_readdata_release(struct kref *refcount)
+{
+	struct cifs_readdata *rdata = container_of(refcount,
+					struct cifs_readdata, refcount);
+	unsigned int i;
+
+	kref_put(&rdata->ctx->refcount, cifs_aio_ctx_release);
+	for (i = 0; i < rdata->nr_pages; i++) {
+		put_page(rdata->pages[i]);
+	}
+	cifs_readdata_release(refcount);
+}
+
+/**
+ * cifs_readdata_to_iov - copy data from pages in response to an iovec
+ * @rdata:	the readdata response with list of pages holding data
+ * @iter:	destination for our data
+ *
+ * This function copies data from a list of pages in a readdata response into
+ * an array of iovecs. It will first calculate where the data should go
+ * based on the info in the readdata and then copy the data into that spot.
+ */
+static int
+cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter)
+{
+	size_t remaining = rdata->got_bytes;
+	unsigned int i;
+
+	for (i = 0; i < rdata->nr_pages; i++) {
+		struct page *page = rdata->pages[i];
+		size_t copy = min_t(size_t, remaining, PAGE_SIZE);
+		size_t written;
+
+		if (unlikely(iov_iter_is_pipe(iter))) {
+			void *addr = kmap_atomic(page);
+
+			written = copy_to_iter(addr, copy, iter);
+			kunmap_atomic(addr);
+		} else
+			written = copy_page_to_iter(page, 0, copy, iter);
+		remaining -= written;
+		if (written < copy && iov_iter_count(iter) > 0)
+			break;
+	}
+	return remaining ? -EFAULT : 0;
+}
+
+static void collect_uncached_read_data(struct cifs_aio_ctx *ctx);
+
+static void
+cifs_uncached_readv_complete(struct work_struct *work)
+{
+	struct cifs_readdata *rdata = container_of(work,
+						struct cifs_readdata, work);
+
+	complete(&rdata->done);
+	collect_uncached_read_data(rdata->ctx);
+	/* the below call can possibly free the last ref to aio ctx */
+	kref_put(&rdata->refcount, cifs_uncached_readdata_release);
+}
+
+static int
+uncached_fill_pages(struct TCP_Server_Info *server,
+		    struct cifs_readdata *rdata, struct iov_iter *iter,
+		    unsigned int len)
+{
+	int result = 0;
+	unsigned int i;
+	unsigned int nr_pages = rdata->nr_pages;
+	unsigned int page_offset = rdata->page_offset;
+
+	rdata->got_bytes = 0;
+	rdata->tailsz = PAGE_SIZE;
+	for (i = 0; i < nr_pages; i++) {
+		struct page *page = rdata->pages[i];
+		size_t n;
+		unsigned int segment_size = rdata->pagesz;
+
+		if (i == 0)
+			segment_size -= page_offset;
+		else
+			page_offset = 0;
+
+
+		if (len <= 0) {
+			/* no need to hold page hostage */
+			rdata->pages[i] = NULL;
+			rdata->nr_pages--;
+			put_page(page);
+			continue;
+		}
+
+		n = len;
+		if (len >= segment_size)
+			/* enough data to fill the page */
+			n = segment_size;
+		else
+			rdata->tailsz = len;
+		len -= n;
+
+		if (iter)
+			result = copy_page_from_iter(
+					page, page_offset, n, iter);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+		else if (rdata->mr)
+			result = n;
+#endif
+		else
+			result = cifs_read_page_from_socket(
+					server, page, page_offset, n);
+		if (result < 0)
+			break;
+
+		rdata->got_bytes += result;
+	}
+
+	return result != -ECONNABORTED && rdata->got_bytes > 0 ?
+						rdata->got_bytes : result;
+}
+
+static int
+cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
+			      struct cifs_readdata *rdata, unsigned int len)
+{
+	return uncached_fill_pages(server, rdata, NULL, len);
+}
+
+static int
+cifs_uncached_copy_into_pages(struct TCP_Server_Info *server,
+			      struct cifs_readdata *rdata,
+			      struct iov_iter *iter)
+{
+	return uncached_fill_pages(server, rdata, iter, iter->count);
+}
+
+static int cifs_resend_rdata(struct cifs_readdata *rdata,
+			struct list_head *rdata_list,
+			struct cifs_aio_ctx *ctx)
+{
+	unsigned int rsize;
+	struct cifs_credits credits;
+	int rc;
+	struct TCP_Server_Info *server;
+
+	/* XXX: should we pick a new channel here? */
+	server = rdata->server;
+
+	do {
+		if (rdata->cfile->invalidHandle) {
+			rc = cifs_reopen_file(rdata->cfile, true);
+			if (rc == -EAGAIN)
+				continue;
+			else if (rc)
+				break;
+		}
+
+		/*
+		 * Wait for credits to resend this rdata.
+		 * Note: we are attempting to resend the whole rdata not in
+		 * segments
+		 */
+		do {
+			rc = server->ops->wait_mtu_credits(server, rdata->bytes,
+						&rsize, &credits);
+
+			if (rc)
+				goto fail;
+
+			if (rsize < rdata->bytes) {
+				add_credits_and_wake_if(server, &credits, 0);
+				msleep(1000);
+			}
+		} while (rsize < rdata->bytes);
+		rdata->credits = credits;
+
+		rc = adjust_credits(server, &rdata->credits, rdata->bytes);
+		if (!rc) {
+			if (rdata->cfile->invalidHandle)
+				rc = -EAGAIN;
+			else {
+#ifdef CONFIG_CIFS_SMB_DIRECT
+				if (rdata->mr) {
+					rdata->mr->need_invalidate = true;
+					smbd_deregister_mr(rdata->mr);
+					rdata->mr = NULL;
+				}
+#endif
+				rc = server->ops->async_readv(rdata);
+			}
+		}
+
+		/* If the read was successfully sent, we are done */
+		if (!rc) {
+			/* Add to aio pending list */
+			list_add_tail(&rdata->list, rdata_list);
+			return 0;
+		}
+
+		/* Roll back credits and retry if needed */
+		add_credits_and_wake_if(server, &rdata->credits, 0);
+	} while (rc == -EAGAIN);
+
+fail:
+	kref_put(&rdata->refcount, cifs_uncached_readdata_release);
+	return rc;
+}
+
+static int
+cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
+		     struct cifs_sb_info *cifs_sb, struct list_head *rdata_list,
+		     struct cifs_aio_ctx *ctx)
+{
+	struct cifs_readdata *rdata;
+	unsigned int npages, rsize;
+	struct cifs_credits credits_on_stack;
+	struct cifs_credits *credits = &credits_on_stack;
+	size_t cur_len;
+	int rc;
+	pid_t pid;
+	struct TCP_Server_Info *server;
+	struct page **pagevec;
+	size_t start;
+	struct iov_iter direct_iov = ctx->iter;
+
+	server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
+		pid = open_file->pid;
+	else
+		pid = current->tgid;
+
+	if (ctx->direct_io)
+		iov_iter_advance(&direct_iov, offset - ctx->pos);
+
+	do {
+		if (open_file->invalidHandle) {
+			rc = cifs_reopen_file(open_file, true);
+			if (rc == -EAGAIN)
+				continue;
+			else if (rc)
+				break;
+		}
+
+		if (cifs_sb->ctx->rsize == 0)
+			cifs_sb->ctx->rsize =
+				server->ops->negotiate_rsize(tlink_tcon(open_file->tlink),
+							     cifs_sb->ctx);
+
+		rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize,
+						   &rsize, credits);
+		if (rc)
+			break;
+
+		cur_len = min_t(const size_t, len, rsize);
+
+		if (ctx->direct_io) {
+			ssize_t result;
+
+			result = iov_iter_get_pages_alloc2(
+					&direct_iov, &pagevec,
+					cur_len, &start);
+			if (result < 0) {
+				cifs_dbg(VFS,
+					 "Couldn't get user pages (rc=%zd) iter type %d iov_offset %zd count %zd\n",
+					 result, iov_iter_type(&direct_iov),
+					 direct_iov.iov_offset,
+					 direct_iov.count);
+				dump_stack();
+
+				rc = result;
+				add_credits_and_wake_if(server, credits, 0);
+				break;
+			}
+			cur_len = (size_t)result;
+
+			rdata = cifs_readdata_direct_alloc(
+					pagevec, cifs_uncached_readv_complete);
+			if (!rdata) {
+				add_credits_and_wake_if(server, credits, 0);
+				rc = -ENOMEM;
+				break;
+			}
+
+			npages = (cur_len + start + PAGE_SIZE-1) / PAGE_SIZE;
+			rdata->page_offset = start;
+			rdata->tailsz = npages > 1 ?
+				cur_len-(PAGE_SIZE-start)-(npages-2)*PAGE_SIZE :
+				cur_len;
+
+		} else {
+
+			npages = DIV_ROUND_UP(cur_len, PAGE_SIZE);
+			/* allocate a readdata struct */
+			rdata = cifs_readdata_alloc(npages,
+					    cifs_uncached_readv_complete);
+			if (!rdata) {
+				add_credits_and_wake_if(server, credits, 0);
+				rc = -ENOMEM;
+				break;
+			}
+
+			rc = cifs_read_allocate_pages(rdata, npages);
+			if (rc) {
+				kvfree(rdata->pages);
+				kfree(rdata);
+				add_credits_and_wake_if(server, credits, 0);
+				break;
+			}
+
+			rdata->tailsz = PAGE_SIZE;
+		}
+
+		rdata->server = server;
+		rdata->cfile = cifsFileInfo_get(open_file);
+		rdata->nr_pages = npages;
+		rdata->offset = offset;
+		rdata->bytes = cur_len;
+		rdata->pid = pid;
+		rdata->pagesz = PAGE_SIZE;
+		rdata->read_into_pages = cifs_uncached_read_into_pages;
+		rdata->copy_into_pages = cifs_uncached_copy_into_pages;
+		rdata->credits = credits_on_stack;
+		rdata->ctx = ctx;
+		kref_get(&ctx->refcount);
+
+		rc = adjust_credits(server, &rdata->credits, rdata->bytes);
+
+		if (!rc) {
+			if (rdata->cfile->invalidHandle)
+				rc = -EAGAIN;
+			else
+				rc = server->ops->async_readv(rdata);
+		}
+
+		if (rc) {
+			add_credits_and_wake_if(server, &rdata->credits, 0);
+			kref_put(&rdata->refcount,
+				cifs_uncached_readdata_release);
+			if (rc == -EAGAIN) {
+				iov_iter_revert(&direct_iov, cur_len);
+				continue;
+			}
+			break;
+		}
+
+		list_add_tail(&rdata->list, rdata_list);
+		offset += cur_len;
+		len -= cur_len;
+	} while (len > 0);
+
+	return rc;
+}
+
+static void
+collect_uncached_read_data(struct cifs_aio_ctx *ctx)
+{
+	struct cifs_readdata *rdata, *tmp;
+	struct iov_iter *to = &ctx->iter;
+	struct cifs_sb_info *cifs_sb;
+	int rc;
+
+	cifs_sb = CIFS_SB(ctx->cfile->dentry->d_sb);
+
+	mutex_lock(&ctx->aio_mutex);
+
+	if (list_empty(&ctx->list)) {
+		mutex_unlock(&ctx->aio_mutex);
+		return;
+	}
+
+	rc = ctx->rc;
+	/* the loop below should proceed in the order of increasing offsets */
+again:
+	list_for_each_entry_safe(rdata, tmp, &ctx->list, list) {
+		if (!rc) {
+			if (!try_wait_for_completion(&rdata->done)) {
+				mutex_unlock(&ctx->aio_mutex);
+				return;
+			}
+
+			if (rdata->result == -EAGAIN) {
+				/* resend call if it's a retryable error */
+				struct list_head tmp_list;
+				unsigned int got_bytes = rdata->got_bytes;
+
+				list_del_init(&rdata->list);
+				INIT_LIST_HEAD(&tmp_list);
+
+				/*
+				 * Got a part of data and then reconnect has
+				 * happened -- fill the buffer and continue
+				 * reading.
+				 */
+				if (got_bytes && got_bytes < rdata->bytes) {
+					rc = 0;
+					if (!ctx->direct_io)
+						rc = cifs_readdata_to_iov(rdata, to);
+					if (rc) {
+						kref_put(&rdata->refcount,
+							cifs_uncached_readdata_release);
+						continue;
+					}
+				}
+
+				if (ctx->direct_io) {
+					/*
+					 * Re-use rdata as this is a
+					 * direct I/O
+					 */
+					rc = cifs_resend_rdata(
+						rdata,
+						&tmp_list, ctx);
+				} else {
+					rc = cifs_send_async_read(
+						rdata->offset + got_bytes,
+						rdata->bytes - got_bytes,
+						rdata->cfile, cifs_sb,
+						&tmp_list, ctx);
+
+					kref_put(&rdata->refcount,
+						cifs_uncached_readdata_release);
+				}
+
+				list_splice(&tmp_list, &ctx->list);
+
+				goto again;
+			} else if (rdata->result)
+				rc = rdata->result;
+			else if (!ctx->direct_io)
+				rc = cifs_readdata_to_iov(rdata, to);
+
+			/* if there was a short read -- discard anything left */
+			if (rdata->got_bytes && rdata->got_bytes < rdata->bytes)
+				rc = -ENODATA;
+
+			ctx->total_len += rdata->got_bytes;
+		}
+		list_del_init(&rdata->list);
+		kref_put(&rdata->refcount, cifs_uncached_readdata_release);
+	}
+
+	if (!ctx->direct_io)
+		ctx->total_len = ctx->len - iov_iter_count(to);
+
+	/* mask nodata case */
+	if (rc == -ENODATA)
+		rc = 0;
+
+	ctx->rc = (rc == 0) ? (ssize_t)ctx->total_len : rc;
+
+	mutex_unlock(&ctx->aio_mutex);
+
+	if (ctx->iocb && ctx->iocb->ki_complete)
+		ctx->iocb->ki_complete(ctx->iocb, ctx->rc);
+	else
+		complete(&ctx->done);
+}
+
+static ssize_t __cifs_readv(
+	struct kiocb *iocb, struct iov_iter *to, bool direct)
+{
+	size_t len;
+	struct file *file = iocb->ki_filp;
+	struct cifs_sb_info *cifs_sb;
+	struct cifsFileInfo *cfile;
+	struct cifs_tcon *tcon;
+	ssize_t rc, total_read = 0;
+	loff_t offset = iocb->ki_pos;
+	struct cifs_aio_ctx *ctx;
+
+	/*
+	 * iov_iter_get_pages_alloc() doesn't work with ITER_KVEC,
+	 * fall back to data copy read path
+	 * this could be improved by getting pages directly in ITER_KVEC
+	 */
+	if (direct && iov_iter_is_kvec(to)) {
+		cifs_dbg(FYI, "use non-direct cifs_user_readv for kvec I/O\n");
+		direct = false;
+	}
+
+	len = iov_iter_count(to);
+	if (!len)
+		return 0;
+
+	cifs_sb = CIFS_FILE_SB(file);
+	cfile = file->private_data;
+	tcon = tlink_tcon(cfile->tlink);
+
+	if (!tcon->ses->server->ops->async_readv)
+		return -ENOSYS;
+
+	if ((file->f_flags & O_ACCMODE) == O_WRONLY)
+		cifs_dbg(FYI, "attempting read on write only file instance\n");
+
+	ctx = cifs_aio_ctx_alloc();
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->cfile = cifsFileInfo_get(cfile);
+
+	if (!is_sync_kiocb(iocb))
+		ctx->iocb = iocb;
+
+	if (user_backed_iter(to))
+		ctx->should_dirty = true;
+
+	if (direct) {
+		ctx->pos = offset;
+		ctx->direct_io = true;
+		ctx->iter = *to;
+		ctx->len = len;
+	} else {
+		rc = setup_aio_ctx_iter(ctx, to, ITER_DEST);
+		if (rc) {
+			kref_put(&ctx->refcount, cifs_aio_ctx_release);
+			return rc;
+		}
+		len = ctx->len;
+	}
+
+	if (direct) {
+		rc = filemap_write_and_wait_range(file->f_inode->i_mapping,
+						  offset, offset + len - 1);
+		if (rc) {
+			kref_put(&ctx->refcount, cifs_aio_ctx_release);
+			return -EAGAIN;
+		}
+	}
+
+	/* grab a lock here due to read response handlers can access ctx */
+	mutex_lock(&ctx->aio_mutex);
+
+	rc = cifs_send_async_read(offset, len, cfile, cifs_sb, &ctx->list, ctx);
+
+	/* if at least one read request send succeeded, then reset rc */
+	if (!list_empty(&ctx->list))
+		rc = 0;
+
+	mutex_unlock(&ctx->aio_mutex);
+
+	if (rc) {
+		kref_put(&ctx->refcount, cifs_aio_ctx_release);
+		return rc;
+	}
+
+	if (!is_sync_kiocb(iocb)) {
+		kref_put(&ctx->refcount, cifs_aio_ctx_release);
+		return -EIOCBQUEUED;
+	}
+
+	rc = wait_for_completion_killable(&ctx->done);
+	if (rc) {
+		mutex_lock(&ctx->aio_mutex);
+		ctx->rc = rc = -EINTR;
+		total_read = ctx->total_len;
+		mutex_unlock(&ctx->aio_mutex);
+	} else {
+		rc = ctx->rc;
+		total_read = ctx->total_len;
+	}
+
+	kref_put(&ctx->refcount, cifs_aio_ctx_release);
+
+	if (total_read) {
+		iocb->ki_pos += total_read;
+		return total_read;
+	}
+	return rc;
+}
+
+ssize_t cifs_direct_readv(struct kiocb *iocb, struct iov_iter *to)
+{
+	return __cifs_readv(iocb, to, true);
+}
+
+ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to)
+{
+	return __cifs_readv(iocb, to, false);
+}
+
+ssize_t
+cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifsFileInfo *cfile = (struct cifsFileInfo *)
+						iocb->ki_filp->private_data;
+	struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+	int rc = -EACCES;
+
+	/*
+	 * In strict cache mode we need to read from the server all the time
+	 * if we don't have level II oplock because the server can delay mtime
+	 * change - so we can't make a decision about inode invalidating.
+	 * And we can also fail with pagereading if there are mandatory locks
+	 * on pages affected by this read but not on the region from pos to
+	 * pos+len-1.
+	 */
+	if (!CIFS_CACHE_READ(cinode))
+		return cifs_user_readv(iocb, to);
+
+	if (cap_unix(tcon->ses) &&
+	    (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+	    ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+		return generic_file_read_iter(iocb, to);
+
+	/*
+	 * We need to hold the sem to be sure nobody modifies lock list
+	 * with a brlock that prevents reading.
+	 */
+	down_read(&cinode->lock_sem);
+	if (!cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(to),
+				     tcon->ses->server->vals->shared_lock_type,
+				     0, NULL, CIFS_READ_OP))
+		rc = generic_file_read_iter(iocb, to);
+	up_read(&cinode->lock_sem);
+	return rc;
+}
+
+static ssize_t
+cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
+{
+	int rc = -EACCES;
+	unsigned int bytes_read = 0;
+	unsigned int total_read;
+	unsigned int current_read_size;
+	unsigned int rsize;
+	struct cifs_sb_info *cifs_sb;
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	unsigned int xid;
+	char *cur_offset;
+	struct cifsFileInfo *open_file;
+	struct cifs_io_parms io_parms = {0};
+	int buf_type = CIFS_NO_BUFFER;
+	__u32 pid;
+
+	xid = get_xid();
+	cifs_sb = CIFS_FILE_SB(file);
+
+	/* FIXME: set up handlers for larger reads and/or convert to async */
+	rsize = min_t(unsigned int, cifs_sb->ctx->rsize, CIFSMaxBufSize);
+
+	if (file->private_data == NULL) {
+		rc = -EBADF;
+		free_xid(xid);
+		return rc;
+	}
+	open_file = file->private_data;
+	tcon = tlink_tcon(open_file->tlink);
+	server = cifs_pick_channel(tcon->ses);
+
+	if (!server->ops->sync_read) {
+		free_xid(xid);
+		return -ENOSYS;
+	}
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
+		pid = open_file->pid;
+	else
+		pid = current->tgid;
+
+	if ((file->f_flags & O_ACCMODE) == O_WRONLY)
+		cifs_dbg(FYI, "attempting read on write only file instance\n");
+
+	for (total_read = 0, cur_offset = read_data; read_size > total_read;
+	     total_read += bytes_read, cur_offset += bytes_read) {
+		do {
+			current_read_size = min_t(uint, read_size - total_read,
+						  rsize);
+			/*
+			 * For windows me and 9x we do not want to request more
+			 * than it negotiated since it will refuse the read
+			 * then.
+			 */
+			if (!(tcon->ses->capabilities &
+				tcon->ses->server->vals->cap_large_files)) {
+				current_read_size = min_t(uint,
+					current_read_size, CIFSMaxBufSize);
+			}
+			if (open_file->invalidHandle) {
+				rc = cifs_reopen_file(open_file, true);
+				if (rc != 0)
+					break;
+			}
+			io_parms.pid = pid;
+			io_parms.tcon = tcon;
+			io_parms.offset = *offset;
+			io_parms.length = current_read_size;
+			io_parms.server = server;
+			rc = server->ops->sync_read(xid, &open_file->fid, &io_parms,
+						    &bytes_read, &cur_offset,
+						    &buf_type);
+		} while (rc == -EAGAIN);
+
+		if (rc || (bytes_read == 0)) {
+			if (total_read) {
+				break;
+			} else {
+				free_xid(xid);
+				return rc;
+			}
+		} else {
+			cifs_stats_bytes_read(tcon, total_read);
+			*offset += bytes_read;
+		}
+	}
+	free_xid(xid);
+	return total_read;
+}
+
+/*
+ * If the page is mmap'ed into a process' page tables, then we need to make
+ * sure that it doesn't change while being written back.
+ */
+static vm_fault_t
+cifs_page_mkwrite(struct vm_fault *vmf)
+{
+	struct page *page = vmf->page;
+
+	/* Wait for the page to be written to the cache before we allow it to
+	 * be modified.  We then assume the entire page will need writing back.
+	 */
+#ifdef CONFIG_CIFS_FSCACHE
+	if (PageFsCache(page) &&
+	    wait_on_page_fscache_killable(page) < 0)
+		return VM_FAULT_RETRY;
+#endif
+
+	wait_on_page_writeback(page);
+
+	if (lock_page_killable(page) < 0)
+		return VM_FAULT_RETRY;
+	return VM_FAULT_LOCKED;
+}
+
+static const struct vm_operations_struct cifs_file_vm_ops = {
+	.fault = filemap_fault,
+	.map_pages = filemap_map_pages,
+	.page_mkwrite = cifs_page_mkwrite,
+};
+
+int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	int xid, rc = 0;
+	struct inode *inode = file_inode(file);
+
+	xid = get_xid();
+
+	if (!CIFS_CACHE_READ(CIFS_I(inode)))
+		rc = cifs_zap_mapping(inode);
+	if (!rc)
+		rc = generic_file_mmap(file, vma);
+	if (!rc)
+		vma->vm_ops = &cifs_file_vm_ops;
+
+	free_xid(xid);
+	return rc;
+}
+
+int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	int rc, xid;
+
+	xid = get_xid();
+
+	rc = cifs_revalidate_file(file);
+	if (rc)
+		cifs_dbg(FYI, "Validation prior to mmap failed, error=%d\n",
+			 rc);
+	if (!rc)
+		rc = generic_file_mmap(file, vma);
+	if (!rc)
+		vma->vm_ops = &cifs_file_vm_ops;
+
+	free_xid(xid);
+	return rc;
+}
+
+static void
+cifs_readv_complete(struct work_struct *work)
+{
+	unsigned int i, got_bytes;
+	struct cifs_readdata *rdata = container_of(work,
+						struct cifs_readdata, work);
+
+	got_bytes = rdata->got_bytes;
+	for (i = 0; i < rdata->nr_pages; i++) {
+		struct page *page = rdata->pages[i];
+
+		if (rdata->result == 0 ||
+		    (rdata->result == -EAGAIN && got_bytes)) {
+			flush_dcache_page(page);
+			SetPageUptodate(page);
+		} else
+			SetPageError(page);
+
+		if (rdata->result == 0 ||
+		    (rdata->result == -EAGAIN && got_bytes))
+			cifs_readpage_to_fscache(rdata->mapping->host, page);
+
+		unlock_page(page);
+
+		got_bytes -= min_t(unsigned int, PAGE_SIZE, got_bytes);
+
+		put_page(page);
+		rdata->pages[i] = NULL;
+	}
+	kref_put(&rdata->refcount, cifs_readdata_release);
+}
+
+static int
+readpages_fill_pages(struct TCP_Server_Info *server,
+		     struct cifs_readdata *rdata, struct iov_iter *iter,
+		     unsigned int len)
+{
+	int result = 0;
+	unsigned int i;
+	u64 eof;
+	pgoff_t eof_index;
+	unsigned int nr_pages = rdata->nr_pages;
+	unsigned int page_offset = rdata->page_offset;
+
+	/* determine the eof that the server (probably) has */
+	eof = CIFS_I(rdata->mapping->host)->server_eof;
+	eof_index = eof ? (eof - 1) >> PAGE_SHIFT : 0;
+	cifs_dbg(FYI, "eof=%llu eof_index=%lu\n", eof, eof_index);
+
+	rdata->got_bytes = 0;
+	rdata->tailsz = PAGE_SIZE;
+	for (i = 0; i < nr_pages; i++) {
+		struct page *page = rdata->pages[i];
+		unsigned int to_read = rdata->pagesz;
+		size_t n;
+
+		if (i == 0)
+			to_read -= page_offset;
+		else
+			page_offset = 0;
+
+		n = to_read;
+
+		if (len >= to_read) {
+			len -= to_read;
+		} else if (len > 0) {
+			/* enough for partial page, fill and zero the rest */
+			zero_user(page, len + page_offset, to_read - len);
+			n = rdata->tailsz = len;
+			len = 0;
+		} else if (page->index > eof_index) {
+			/*
+			 * The VFS will not try to do readahead past the
+			 * i_size, but it's possible that we have outstanding
+			 * writes with gaps in the middle and the i_size hasn't
+			 * caught up yet. Populate those with zeroed out pages
+			 * to prevent the VFS from repeatedly attempting to
+			 * fill them until the writes are flushed.
+			 */
+			zero_user(page, 0, PAGE_SIZE);
+			flush_dcache_page(page);
+			SetPageUptodate(page);
+			unlock_page(page);
+			put_page(page);
+			rdata->pages[i] = NULL;
+			rdata->nr_pages--;
+			continue;
+		} else {
+			/* no need to hold page hostage */
+			unlock_page(page);
+			put_page(page);
+			rdata->pages[i] = NULL;
+			rdata->nr_pages--;
+			continue;
+		}
+
+		if (iter)
+			result = copy_page_from_iter(
+					page, page_offset, n, iter);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+		else if (rdata->mr)
+			result = n;
+#endif
+		else
+			result = cifs_read_page_from_socket(
+					server, page, page_offset, n);
+		if (result < 0)
+			break;
+
+		rdata->got_bytes += result;
+	}
+
+	return result != -ECONNABORTED && rdata->got_bytes > 0 ?
+						rdata->got_bytes : result;
+}
+
+static int
+cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
+			       struct cifs_readdata *rdata, unsigned int len)
+{
+	return readpages_fill_pages(server, rdata, NULL, len);
+}
+
+static int
+cifs_readpages_copy_into_pages(struct TCP_Server_Info *server,
+			       struct cifs_readdata *rdata,
+			       struct iov_iter *iter)
+{
+	return readpages_fill_pages(server, rdata, iter, iter->count);
+}
+
+static void cifs_readahead(struct readahead_control *ractl)
+{
+	int rc;
+	struct cifsFileInfo *open_file = ractl->file->private_data;
+	struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(ractl->file);
+	struct TCP_Server_Info *server;
+	pid_t pid;
+	unsigned int xid, nr_pages, last_batch_size = 0, cache_nr_pages = 0;
+	pgoff_t next_cached = ULONG_MAX;
+	bool caching = fscache_cookie_enabled(cifs_inode_cookie(ractl->mapping->host)) &&
+		cifs_inode_cookie(ractl->mapping->host)->cache_priv;
+	bool check_cache = caching;
+
+	xid = get_xid();
+
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
+		pid = open_file->pid;
+	else
+		pid = current->tgid;
+
+	rc = 0;
+	server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
+
+	cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n",
+		 __func__, ractl->file, ractl->mapping, readahead_count(ractl));
+
+	/*
+	 * Chop the readahead request up into rsize-sized read requests.
+	 */
+	while ((nr_pages = readahead_count(ractl) - last_batch_size)) {
+		unsigned int i, got, rsize;
+		struct page *page;
+		struct cifs_readdata *rdata;
+		struct cifs_credits credits_on_stack;
+		struct cifs_credits *credits = &credits_on_stack;
+		pgoff_t index = readahead_index(ractl) + last_batch_size;
+
+		/*
+		 * Find out if we have anything cached in the range of
+		 * interest, and if so, where the next chunk of cached data is.
+		 */
+		if (caching) {
+			if (check_cache) {
+				rc = cifs_fscache_query_occupancy(
+					ractl->mapping->host, index, nr_pages,
+					&next_cached, &cache_nr_pages);
+				if (rc < 0)
+					caching = false;
+				check_cache = false;
+			}
+
+			if (index == next_cached) {
+				/*
+				 * TODO: Send a whole batch of pages to be read
+				 * by the cache.
+				 */
+				struct folio *folio = readahead_folio(ractl);
+
+				last_batch_size = folio_nr_pages(folio);
+				if (cifs_readpage_from_fscache(ractl->mapping->host,
+							       &folio->page) < 0) {
+					/*
+					 * TODO: Deal with cache read failure
+					 * here, but for the moment, delegate
+					 * that to readpage.
+					 */
+					caching = false;
+				}
+				folio_unlock(folio);
+				next_cached++;
+				cache_nr_pages--;
+				if (cache_nr_pages == 0)
+					check_cache = true;
+				continue;
+			}
+		}
+
+		if (open_file->invalidHandle) {
+			rc = cifs_reopen_file(open_file, true);
+			if (rc) {
+				if (rc == -EAGAIN)
+					continue;
+				break;
+			}
+		}
+
+		if (cifs_sb->ctx->rsize == 0)
+			cifs_sb->ctx->rsize =
+				server->ops->negotiate_rsize(tlink_tcon(open_file->tlink),
+							     cifs_sb->ctx);
+
+		rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize,
+						   &rsize, credits);
+		if (rc)
+			break;
+		nr_pages = min_t(size_t, rsize / PAGE_SIZE, readahead_count(ractl));
+		nr_pages = min_t(size_t, nr_pages, next_cached - index);
+
+		/*
+		 * Give up immediately if rsize is too small to read an entire
+		 * page. The VFS will fall back to readpage. We should never
+		 * reach this point however since we set ra_pages to 0 when the
+		 * rsize is smaller than a cache page.
+		 */
+		if (unlikely(!nr_pages)) {
+			add_credits_and_wake_if(server, credits, 0);
+			break;
+		}
+
+		rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete);
+		if (!rdata) {
+			/* best to give up if we're out of mem */
+			add_credits_and_wake_if(server, credits, 0);
+			break;
+		}
+
+		got = __readahead_batch(ractl, rdata->pages, nr_pages);
+		if (got != nr_pages) {
+			pr_warn("__readahead_batch() returned %u/%u\n",
+				got, nr_pages);
+			nr_pages = got;
+		}
+
+		rdata->nr_pages = nr_pages;
+		rdata->bytes	= readahead_batch_length(ractl);
+		rdata->cfile	= cifsFileInfo_get(open_file);
+		rdata->server	= server;
+		rdata->mapping	= ractl->mapping;
+		rdata->offset	= readahead_pos(ractl);
+		rdata->pid	= pid;
+		rdata->pagesz	= PAGE_SIZE;
+		rdata->tailsz	= PAGE_SIZE;
+		rdata->read_into_pages = cifs_readpages_read_into_pages;
+		rdata->copy_into_pages = cifs_readpages_copy_into_pages;
+		rdata->credits	= credits_on_stack;
+
+		rc = adjust_credits(server, &rdata->credits, rdata->bytes);
+		if (!rc) {
+			if (rdata->cfile->invalidHandle)
+				rc = -EAGAIN;
+			else
+				rc = server->ops->async_readv(rdata);
+		}
+
+		if (rc) {
+			add_credits_and_wake_if(server, &rdata->credits, 0);
+			for (i = 0; i < rdata->nr_pages; i++) {
+				page = rdata->pages[i];
+				unlock_page(page);
+				put_page(page);
+			}
+			/* Fallback to the readpage in error/reconnect cases */
+			kref_put(&rdata->refcount, cifs_readdata_release);
+			break;
+		}
+
+		kref_put(&rdata->refcount, cifs_readdata_release);
+		last_batch_size = nr_pages;
+	}
+
+	free_xid(xid);
+}
+
+/*
+ * cifs_readpage_worker must be called with the page pinned
+ */
+static int cifs_readpage_worker(struct file *file, struct page *page,
+	loff_t *poffset)
+{
+	char *read_data;
+	int rc;
+
+	/* Is the page cached? */
+	rc = cifs_readpage_from_fscache(file_inode(file), page);
+	if (rc == 0)
+		goto read_complete;
+
+	read_data = kmap(page);
+	/* for reads over a certain size could initiate async read ahead */
+
+	rc = cifs_read(file, read_data, PAGE_SIZE, poffset);
+
+	if (rc < 0)
+		goto io_error;
+	else
+		cifs_dbg(FYI, "Bytes read %d\n", rc);
+
+	/* we do not want atime to be less than mtime, it broke some apps */
+	file_inode(file)->i_atime = current_time(file_inode(file));
+	if (timespec64_compare(&(file_inode(file)->i_atime), &(file_inode(file)->i_mtime)))
+		file_inode(file)->i_atime = file_inode(file)->i_mtime;
+	else
+		file_inode(file)->i_atime = current_time(file_inode(file));
+
+	if (PAGE_SIZE > rc)
+		memset(read_data + rc, 0, PAGE_SIZE - rc);
+
+	flush_dcache_page(page);
+	SetPageUptodate(page);
+
+	/* send this page to the cache */
+	cifs_readpage_to_fscache(file_inode(file), page);
+
+	rc = 0;
+
+io_error:
+	kunmap(page);
+
+read_complete:
+	unlock_page(page);
+	return rc;
+}
+
+static int cifs_read_folio(struct file *file, struct folio *folio)
+{
+	struct page *page = &folio->page;
+	loff_t offset = page_file_offset(page);
+	int rc = -EACCES;
+	unsigned int xid;
+
+	xid = get_xid();
+
+	if (file->private_data == NULL) {
+		rc = -EBADF;
+		free_xid(xid);
+		return rc;
+	}
+
+	cifs_dbg(FYI, "read_folio %p at offset %d 0x%x\n",
+		 page, (int)offset, (int)offset);
+
+	rc = cifs_readpage_worker(file, page, &offset);
+
+	free_xid(xid);
+	return rc;
+}
+
+static int is_inode_writable(struct cifsInodeInfo *cifs_inode)
+{
+	struct cifsFileInfo *open_file;
+
+	spin_lock(&cifs_inode->open_file_lock);
+	list_for_each_entry(open_file, &cifs_inode->openFileList, flist) {
+		if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
+			spin_unlock(&cifs_inode->open_file_lock);
+			return 1;
+		}
+	}
+	spin_unlock(&cifs_inode->open_file_lock);
+	return 0;
+}
+
+/* We do not want to update the file size from server for inodes
+   open for write - to avoid races with writepage extending
+   the file - in the future we could consider allowing
+   refreshing the inode only on increases in the file size
+   but this is tricky to do without racing with writebehind
+   page caching in the current Linux kernel design */
+bool is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file)
+{
+	if (!cifsInode)
+		return true;
+
+	if (is_inode_writable(cifsInode)) {
+		/* This inode is open for write at least once */
+		struct cifs_sb_info *cifs_sb;
+
+		cifs_sb = CIFS_SB(cifsInode->netfs.inode.i_sb);
+		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO) {
+			/* since no page cache to corrupt on directio
+			we can change size safely */
+			return true;
+		}
+
+		if (i_size_read(&cifsInode->netfs.inode) < end_of_file)
+			return true;
+
+		return false;
+	} else
+		return true;
+}
+
+static int cifs_write_begin(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len,
+			struct page **pagep, void **fsdata)
+{
+	int oncethru = 0;
+	pgoff_t index = pos >> PAGE_SHIFT;
+	loff_t offset = pos & (PAGE_SIZE - 1);
+	loff_t page_start = pos & PAGE_MASK;
+	loff_t i_size;
+	struct page *page;
+	int rc = 0;
+
+	cifs_dbg(FYI, "write_begin from %lld len %d\n", (long long)pos, len);
+
+start:
+	page = grab_cache_page_write_begin(mapping, index);
+	if (!page) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (PageUptodate(page))
+		goto out;
+
+	/*
+	 * If we write a full page it will be up to date, no need to read from
+	 * the server. If the write is short, we'll end up doing a sync write
+	 * instead.
+	 */
+	if (len == PAGE_SIZE)
+		goto out;
+
+	/*
+	 * optimize away the read when we have an oplock, and we're not
+	 * expecting to use any of the data we'd be reading in. That
+	 * is, when the page lies beyond the EOF, or straddles the EOF
+	 * and the write will cover all of the existing data.
+	 */
+	if (CIFS_CACHE_READ(CIFS_I(mapping->host))) {
+		i_size = i_size_read(mapping->host);
+		if (page_start >= i_size ||
+		    (offset == 0 && (pos + len) >= i_size)) {
+			zero_user_segments(page, 0, offset,
+					   offset + len,
+					   PAGE_SIZE);
+			/*
+			 * PageChecked means that the parts of the page
+			 * to which we're not writing are considered up
+			 * to date. Once the data is copied to the
+			 * page, it can be set uptodate.
+			 */
+			SetPageChecked(page);
+			goto out;
+		}
+	}
+
+	if ((file->f_flags & O_ACCMODE) != O_WRONLY && !oncethru) {
+		/*
+		 * might as well read a page, it is fast enough. If we get
+		 * an error, we don't need to return it. cifs_write_end will
+		 * do a sync write instead since PG_uptodate isn't set.
+		 */
+		cifs_readpage_worker(file, page, &page_start);
+		put_page(page);
+		oncethru = 1;
+		goto start;
+	} else {
+		/* we could try using another file handle if there is one -
+		   but how would we lock it to prevent close of that handle
+		   racing with this read? In any case
+		   this will be written out by write_end so is fine */
+	}
+out:
+	*pagep = page;
+	return rc;
+}
+
+static bool cifs_release_folio(struct folio *folio, gfp_t gfp)
+{
+	if (folio_test_private(folio))
+		return 0;
+	if (folio_test_fscache(folio)) {
+		if (current_is_kswapd() || !(gfp & __GFP_FS))
+			return false;
+		folio_wait_fscache(folio);
+	}
+	fscache_note_page_release(cifs_inode_cookie(folio->mapping->host));
+	return true;
+}
+
+static void cifs_invalidate_folio(struct folio *folio, size_t offset,
+				 size_t length)
+{
+	folio_wait_fscache(folio);
+}
+
+static int cifs_launder_folio(struct folio *folio)
+{
+	int rc = 0;
+	loff_t range_start = folio_pos(folio);
+	loff_t range_end = range_start + folio_size(folio);
+	struct writeback_control wbc = {
+		.sync_mode = WB_SYNC_ALL,
+		.nr_to_write = 0,
+		.range_start = range_start,
+		.range_end = range_end,
+	};
+
+	cifs_dbg(FYI, "Launder page: %lu\n", folio->index);
+
+	if (folio_clear_dirty_for_io(folio))
+		rc = cifs_writepage_locked(&folio->page, &wbc);
+
+	folio_wait_fscache(folio);
+	return rc;
+}
+
+void cifs_oplock_break(struct work_struct *work)
+{
+	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
+						  oplock_break);
+	struct inode *inode = d_inode(cfile->dentry);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	struct tcon_link *tlink;
+	int rc = 0;
+	bool purge_cache = false, oplock_break_cancelled;
+	__u64 persistent_fid, volatile_fid;
+	__u16 net_fid;
+
+	wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
+			TASK_UNINTERRUPTIBLE);
+
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink))
+		goto out;
+	tcon = tlink_tcon(tlink);
+	server = tcon->ses->server;
+
+	server->ops->downgrade_oplock(server, cinode, cfile->oplock_level,
+				      cfile->oplock_epoch, &purge_cache);
+
+	if (!CIFS_CACHE_WRITE(cinode) && CIFS_CACHE_READ(cinode) &&
+						cifs_has_mand_locks(cinode)) {
+		cifs_dbg(FYI, "Reset oplock to None for inode=%p due to mand locks\n",
+			 inode);
+		cinode->oplock = 0;
+	}
+
+	if (inode && S_ISREG(inode->i_mode)) {
+		if (CIFS_CACHE_READ(cinode))
+			break_lease(inode, O_RDONLY);
+		else
+			break_lease(inode, O_WRONLY);
+		rc = filemap_fdatawrite(inode->i_mapping);
+		if (!CIFS_CACHE_READ(cinode) || purge_cache) {
+			rc = filemap_fdatawait(inode->i_mapping);
+			mapping_set_error(inode->i_mapping, rc);
+			cifs_zap_mapping(inode);
+		}
+		cifs_dbg(FYI, "Oplock flush inode %p rc %d\n", inode, rc);
+		if (CIFS_CACHE_WRITE(cinode))
+			goto oplock_break_ack;
+	}
+
+	rc = cifs_push_locks(cfile);
+	if (rc)
+		cifs_dbg(VFS, "Push locks rc = %d\n", rc);
+
+oplock_break_ack:
+	/*
+	 * When oplock break is received and there are no active
+	 * file handles but cached, then schedule deferred close immediately.
+	 * So, new open will not use cached handle.
+	 */
+
+	if (!CIFS_CACHE_HANDLE(cinode) && !list_empty(&cinode->deferred_closes))
+		cifs_close_deferred_file(cinode);
+
+	persistent_fid = cfile->fid.persistent_fid;
+	volatile_fid = cfile->fid.volatile_fid;
+	net_fid = cfile->fid.netfid;
+	oplock_break_cancelled = cfile->oplock_break_cancelled;
+
+	_cifsFileInfo_put(cfile, false /* do not wait for ourself */, false);
+	/*
+	 * MS-SMB2 3.2.5.19.1 and 3.2.5.19.2 (and MS-CIFS 3.2.5.42) do not require
+	 * an acknowledgment to be sent when the file has already been closed.
+	 */
+	spin_lock(&cinode->open_file_lock);
+	/* check list empty since can race with kill_sb calling tree disconnect */
+	if (!oplock_break_cancelled && !list_empty(&cinode->openFileList)) {
+		spin_unlock(&cinode->open_file_lock);
+		rc = server->ops->oplock_response(tcon, persistent_fid,
+						  volatile_fid, net_fid, cinode);
+		cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
+	} else
+		spin_unlock(&cinode->open_file_lock);
+
+	cifs_put_tlink(tlink);
+out:
+	cifs_done_oplock_break(cinode);
+}
+
+/*
+ * The presence of cifs_direct_io() in the address space ops vector
+ * allowes open() O_DIRECT flags which would have failed otherwise.
+ *
+ * In the non-cached mode (mount with cache=none), we shunt off direct read and write requests
+ * so this method should never be called.
+ *
+ * Direct IO is not yet supported in the cached mode.
+ */
+static ssize_t
+cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter)
+{
+        /*
+         * FIXME
+         * Eventually need to support direct IO for non forcedirectio mounts
+         */
+        return -EINVAL;
+}
+
+static int cifs_swap_activate(struct swap_info_struct *sis,
+			      struct file *swap_file, sector_t *span)
+{
+	struct cifsFileInfo *cfile = swap_file->private_data;
+	struct inode *inode = swap_file->f_mapping->host;
+	unsigned long blocks;
+	long long isize;
+
+	cifs_dbg(FYI, "swap activate\n");
+
+	if (!swap_file->f_mapping->a_ops->swap_rw)
+		/* Cannot support swap */
+		return -EINVAL;
+
+	spin_lock(&inode->i_lock);
+	blocks = inode->i_blocks;
+	isize = inode->i_size;
+	spin_unlock(&inode->i_lock);
+	if (blocks*512 < isize) {
+		pr_warn("swap activate: swapfile has holes\n");
+		return -EINVAL;
+	}
+	*span = sis->pages;
+
+	pr_warn_once("Swap support over SMB3 is experimental\n");
+
+	/*
+	 * TODO: consider adding ACL (or documenting how) to prevent other
+	 * users (on this or other systems) from reading it
+	 */
+
+
+	/* TODO: add sk_set_memalloc(inet) or similar */
+
+	if (cfile)
+		cfile->swapfile = true;
+	/*
+	 * TODO: Since file already open, we can't open with DENY_ALL here
+	 * but we could add call to grab a byte range lock to prevent others
+	 * from reading or writing the file
+	 */
+
+	sis->flags |= SWP_FS_OPS;
+	return add_swap_extent(sis, 0, sis->max, 0);
+}
+
+static void cifs_swap_deactivate(struct file *file)
+{
+	struct cifsFileInfo *cfile = file->private_data;
+
+	cifs_dbg(FYI, "swap deactivate\n");
+
+	/* TODO: undo sk_set_memalloc(inet) will eventually be needed */
+
+	if (cfile)
+		cfile->swapfile = false;
+
+	/* do we need to unpin (or unlock) the file */
+}
+
+/*
+ * Mark a page as having been made dirty and thus needing writeback.  We also
+ * need to pin the cache object to write back to.
+ */
+#ifdef CONFIG_CIFS_FSCACHE
+static bool cifs_dirty_folio(struct address_space *mapping, struct folio *folio)
+{
+	return fscache_dirty_folio(mapping, folio,
+					cifs_inode_cookie(mapping->host));
+}
+#else
+#define cifs_dirty_folio filemap_dirty_folio
+#endif
+
+const struct address_space_operations cifs_addr_ops = {
+	.read_folio = cifs_read_folio,
+	.readahead = cifs_readahead,
+	.writepage = cifs_writepage,
+	.writepages = cifs_writepages,
+	.write_begin = cifs_write_begin,
+	.write_end = cifs_write_end,
+	.dirty_folio = cifs_dirty_folio,
+	.release_folio = cifs_release_folio,
+	.direct_IO = cifs_direct_io,
+	.invalidate_folio = cifs_invalidate_folio,
+	.launder_folio = cifs_launder_folio,
+	/*
+	 * TODO: investigate and if useful we could add an cifs_migratePage
+	 * helper (under an CONFIG_MIGRATION) in the future, and also
+	 * investigate and add an is_dirty_writeback helper if needed
+	 */
+	.swap_activate = cifs_swap_activate,
+	.swap_deactivate = cifs_swap_deactivate,
+};
+
+/*
+ * cifs_readahead requires the server to support a buffer large enough to
+ * contain the header plus one complete page of data.  Otherwise, we need
+ * to leave cifs_readahead out of the address space operations.
+ */
+const struct address_space_operations cifs_addr_ops_smallbuf = {
+	.read_folio = cifs_read_folio,
+	.writepage = cifs_writepage,
+	.writepages = cifs_writepages,
+	.write_begin = cifs_write_begin,
+	.write_end = cifs_write_end,
+	.dirty_folio = cifs_dirty_folio,
+	.release_folio = cifs_release_folio,
+	.invalidate_folio = cifs_invalidate_folio,
+	.launder_folio = cifs_launder_folio,
+};