Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull third hunk of vfs changes from Al Viro:
 "This contains the ->direct_IO() changes from Omar + saner
  generic_write_checks() + dealing with fcntl()/{read,write}() races
  (mirroring O_APPEND/O_DIRECT into iocb->ki_flags and instead of
  repeatedly looking at ->f_flags, which can be changed by fcntl(2),
  check ->ki_flags - which cannot) + infrastructure bits for dhowells'
  d_inode annotations + Christophs switch of /dev/loop to
  vfs_iter_write()"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (30 commits)
  block: loop: switch to VFS ITER_BVEC
  configfs: Fix inconsistent use of file_inode() vs file->f_path.dentry->d_inode
  VFS: Make pathwalk use d_is_reg() rather than S_ISREG()
  VFS: Fix up debugfs to use d_is_dir() in place of S_ISDIR()
  VFS: Combine inode checks with d_is_negative() and d_is_positive() in pathwalk
  NFS: Don't use d_inode as a variable name
  VFS: Impose ordering on accesses of d_inode and d_flags
  VFS: Add owner-filesystem positive/negative dentry checks
  nfs: generic_write_checks() shouldn't be done on swapout...
  ocfs2: use __generic_file_write_iter()
  mirror O_APPEND and O_DIRECT into iocb->ki_flags
  switch generic_write_checks() to iocb and iter
  ocfs2: move generic_write_checks() before the alignment checks
  ocfs2_file_write_iter: stop messing with ppos
  udf_file_write_iter: reorder and simplify
  fuse: ->direct_IO() doesn't need generic_write_checks()
  ext4_file_write_iter: move generic_write_checks() up
  xfs_file_aio_write_checks: switch to iocb/iov_iter
  generic_write_checks(): drop isblk argument
  blkdev_write_iter: expand generic_file_checks() call in there
  ...

55 files changed, 691 insertions, 861 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 7c3f187d48bf..0a926e2ba3ab 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -196,7 +196,7 @@ prototypes:
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, int);
 	void (*freepage)(struct page *);
-	int (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
+	int (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset);
 	int (*migratepage)(struct address_space *, struct page *, struct page *);
 	int (*launder_page)(struct page *);
 	int (*is_partially_uptodate)(struct page *, unsigned long, unsigned long);
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 207cdca68bed..5d833b32bbcd 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -590,7 +590,7 @@ struct address_space_operations {
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, int);
 	void (*freepage)(struct page *);
-	ssize_t (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
+	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset);
 	/* migrate the contents of a page to the specified target */
 	int (*migratepage) (struct page *, struct page *);
 	int (*launder_page) (struct page *);
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c4fd1e45ce1e..ae3fcb4199e9 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -88,28 +88,6 @@ static int part_shift;
 
 static struct workqueue_struct *loop_wq;
 
-/*
- * Transfer functions
- */
-static int transfer_none(struct loop_device *lo, int cmd,
-			 struct page *raw_page, unsigned raw_off,
-			 struct page *loop_page, unsigned loop_off,
-			 int size, sector_t real_block)
-{
-	char *raw_buf = kmap_atomic(raw_page) + raw_off;
-	char *loop_buf = kmap_atomic(loop_page) + loop_off;
-
-	if (cmd == READ)
-		memcpy(loop_buf, raw_buf, size);
-	else
-		memcpy(raw_buf, loop_buf, size);
-
-	kunmap_atomic(loop_buf);
-	kunmap_atomic(raw_buf);
-	cond_resched();
-	return 0;
-}
-
 static int transfer_xor(struct loop_device *lo, int cmd,
 			struct page *raw_page, unsigned raw_off,
 			struct page *loop_page, unsigned loop_off,
@@ -148,14 +126,13 @@ static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
 
 static struct loop_func_table none_funcs = {
 	.number = LO_CRYPT_NONE,
-	.transfer = transfer_none,
-}; 	
+}; 
 
 static struct loop_func_table xor_funcs = {
 	.number = LO_CRYPT_XOR,
 	.transfer = transfer_xor,
 	.init = xor_init
-}; 	
+}; 
 
 /* xfer_funcs[0] is special - its release function is never called */
 static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
@@ -215,207 +192,169 @@ lo_do_transfer(struct loop_device *lo, int cmd,
 	       struct page *lpage, unsigned loffs,
 	       int size, sector_t rblock)
 {
-	if (unlikely(!lo->transfer))
+	int ret;
+
+	ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
+	if (likely(!ret))
 		return 0;
 
-	return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
+	printk_ratelimited(KERN_ERR
+		"loop: Transfer error at byte offset %llu, length %i.\n",
+		(unsigned long long)rblock << 9, size);
+	return ret;
 }
 
-/**
- * __do_lo_send_write - helper for writing data to a loop device
- *
- * This helper just factors out common code between do_lo_send_direct_write()
- * and do_lo_send_write().
- */
-static int __do_lo_send_write(struct file *file,
-		u8 *buf, const int len, loff_t pos)
+static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
 {
-	struct kvec kvec = {.iov_base = buf, .iov_len = len};
-	struct iov_iter from;
+	struct iov_iter i;
 	ssize_t bw;
 
-	iov_iter_kvec(&from, ITER_KVEC | WRITE, &kvec, 1, len);
+	iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len);
 
 	file_start_write(file);
-	bw = vfs_iter_write(file, &from, &pos);
+	bw = vfs_iter_write(file, &i, ppos);
 	file_end_write(file);
-	if (likely(bw == len))
+
+	if (likely(bw ==  bvec->bv_len))
 		return 0;
-	printk_ratelimited(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n",
-			(unsigned long long)pos, len);
+
+	printk_ratelimited(KERN_ERR
+		"loop: Write error at byte offset %llu, length %i.\n",
+		(unsigned long long)*ppos, bvec->bv_len);
 	if (bw >= 0)
 		bw = -EIO;
 	return bw;
 }
 
-/**
- * do_lo_send_direct_write - helper for writing data to a loop device
- *
- * This is the fast, non-transforming version that does not need double
- * buffering.
- */
-static int do_lo_send_direct_write(struct loop_device *lo,
-		struct bio_vec *bvec, loff_t pos, struct page *page)
+static int lo_write_simple(struct loop_device *lo, struct request *rq,
+		loff_t pos)
 {
-	ssize_t bw = __do_lo_send_write(lo->lo_backing_file,
-			kmap(bvec->bv_page) + bvec->bv_offset,
-			bvec->bv_len, pos);
-	kunmap(bvec->bv_page);
-	cond_resched();
-	return bw;
+	struct bio_vec bvec;
+	struct req_iterator iter;
+	int ret = 0;
+
+	rq_for_each_segment(bvec, rq, iter) {
+		ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
+		if (ret < 0)
+			break;
+		cond_resched();
+	}
+
+	return ret;
 }
 
-/**
- * do_lo_send_write - helper for writing data to a loop device
- *
+/*
  * This is the slow, transforming version that needs to double buffer the
  * data as it cannot do the transformations in place without having direct
  * access to the destination pages of the backing file.
  */
-static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
-		loff_t pos, struct page *page)
+static int lo_write_transfer(struct loop_device *lo, struct request *rq,
+		loff_t pos)
 {
-	int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page,
-			bvec->bv_offset, bvec->bv_len, pos >> 9);
-	if (likely(!ret))
-		return __do_lo_send_write(lo->lo_backing_file,
-				page_address(page), bvec->bv_len,
-				pos);
-	printk_ratelimited(KERN_ERR "loop: Transfer error at byte offset %llu, "
-			"length %i.\n", (unsigned long long)pos, bvec->bv_len);
-	if (ret > 0)
-		ret = -EIO;
-	return ret;
-}
-
-static int lo_send(struct loop_device *lo, struct request *rq, loff_t pos)
-{
-	int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t,
-			struct page *page);
-	struct bio_vec bvec;
+	struct bio_vec bvec, b;
 	struct req_iterator iter;
-	struct page *page = NULL;
+	struct page *page;
 	int ret = 0;
 
-	if (lo->transfer != transfer_none) {
-		page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
-		if (unlikely(!page))
-			goto fail;
-		kmap(page);
-		do_lo_send = do_lo_send_write;
-	} else {
-		do_lo_send = do_lo_send_direct_write;
-	}
+	page = alloc_page(GFP_NOIO);
+	if (unlikely(!page))
+		return -ENOMEM;
 
 	rq_for_each_segment(bvec, rq, iter) {
-		ret = do_lo_send(lo, &bvec, pos, page);
+		ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page,
+			bvec.bv_offset, bvec.bv_len, pos >> 9);
+		if (unlikely(ret))
+			break;
+
+		b.bv_page = page;
+		b.bv_offset = 0;
+		b.bv_len = bvec.bv_len;
+		ret = lo_write_bvec(lo->lo_backing_file, &b, &pos);
 		if (ret < 0)
 			break;
-		pos += bvec.bv_len;
 	}
-	if (page) {
-		kunmap(page);
-		__free_page(page);
-	}
-out:
+
+	__free_page(page);
 	return ret;
-fail:
-	printk_ratelimited(KERN_ERR "loop: Failed to allocate temporary page for write.\n");
-	ret = -ENOMEM;
-	goto out;
 }
 
-struct lo_read_data {
-	struct loop_device *lo;
-	struct page *page;
-	unsigned offset;
-	int bsize;
-};
+static int lo_read_simple(struct loop_device *lo, struct request *rq,
+		loff_t pos)
+{
+	struct bio_vec bvec;
+	struct req_iterator iter;
+	struct iov_iter i;
+	ssize_t len;
 
-static int
-lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
-		struct splice_desc *sd)
-{
-	struct lo_read_data *p = sd->u.data;
-	struct loop_device *lo = p->lo;
-	struct page *page = buf->page;
-	sector_t IV;
-	int size;
-
-	IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) +
-							(buf->offset >> 9);
-	size = sd->len;
-	if (size > p->bsize)
-		size = p->bsize;
-
-	if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) {
-		printk_ratelimited(KERN_ERR "loop: transfer error block %ld\n",
-		       page->index);
-		size = -EINVAL;
-	}
+	rq_for_each_segment(bvec, rq, iter) {
+		iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len);
+		len = vfs_iter_read(lo->lo_backing_file, &i, &pos);
+		if (len < 0)
+			return len;
 
-	flush_dcache_page(p->page);
+		flush_dcache_page(bvec.bv_page);
 
-	if (size > 0)
-		p->offset += size;
+		if (len != bvec.bv_len) {
+			struct bio *bio;
 
-	return size;
-}
+			__rq_for_each_bio(bio, rq)
+				zero_fill_bio(bio);
+			break;
+		}
+		cond_resched();
+	}
 
-static int
-lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)
-{
-	return __splice_from_pipe(pipe, sd, lo_splice_actor);
+	return 0;
 }
 
-static ssize_t
-do_lo_receive(struct loop_device *lo,
-	      struct bio_vec *bvec, int bsize, loff_t pos)
+static int lo_read_transfer(struct loop_device *lo, struct request *rq,
+		loff_t pos)
 {
-	struct lo_read_data cookie;
-	struct splice_desc sd;
-	struct file *file;
-	ssize_t retval;
+	struct bio_vec bvec, b;
+	struct req_iterator iter;
+	struct iov_iter i;
+	struct page *page;
+	ssize_t len;
+	int ret = 0;
 
-	cookie.lo = lo;
-	cookie.page = bvec->bv_page;
-	cookie.offset = bvec->bv_offset;
-	cookie.bsize = bsize;
+	page = alloc_page(GFP_NOIO);
+	if (unlikely(!page))
+		return -ENOMEM;
 
-	sd.len = 0;
-	sd.total_len = bvec->bv_len;
-	sd.flags = 0;
-	sd.pos = pos;
-	sd.u.data = &cookie;
+	rq_for_each_segment(bvec, rq, iter) {
+		loff_t offset = pos;
 
-	file = lo->lo_backing_file;
-	retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);
+		b.bv_page = page;
+		b.bv_offset = 0;
+		b.bv_len = bvec.bv_len;
 
-	return retval;
-}
+		iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len);
+		len = vfs_iter_read(lo->lo_backing_file, &i, &pos);
+		if (len < 0) {
+			ret = len;
+			goto out_free_page;
+		}
 
-static int
-lo_receive(struct loop_device *lo, struct request *rq, int bsize, loff_t pos)
-{
-	struct bio_vec bvec;
-	struct req_iterator iter;
-	ssize_t s;
+		ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page,
+			bvec.bv_offset, len, offset >> 9);
+		if (ret)
+			goto out_free_page;
 
-	rq_for_each_segment(bvec, rq, iter) {
-		s = do_lo_receive(lo, &bvec, bsize, pos);
-		if (s < 0)
-			return s;
+		flush_dcache_page(bvec.bv_page);
 
-		if (s != bvec.bv_len) {
+		if (len != bvec.bv_len) {
 			struct bio *bio;
 
 			__rq_for_each_bio(bio, rq)
 				zero_fill_bio(bio);
 			break;
 		}
-		pos += bvec.bv_len;
 	}
-	return 0;
+
+	ret = 0;
+out_free_page:
+	__free_page(page);
+	return ret;
 }
 
 static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
@@ -464,10 +403,17 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
 			ret = lo_req_flush(lo, rq);
 		else if (rq->cmd_flags & REQ_DISCARD)
 			ret = lo_discard(lo, rq, pos);
+		else if (lo->transfer)
+			ret = lo_write_transfer(lo, rq, pos);
 		else
-			ret = lo_send(lo, rq, pos);
-	} else
-		ret = lo_receive(lo, rq, lo->lo_blocksize, pos);
+			ret = lo_write_simple(lo, rq, pos);
+
+	} else {
+		if (lo->transfer)
+			ret = lo_read_transfer(lo, rq, pos);
+		else
+			ret = lo_read_simple(lo, rq, pos);
+	}
 
 	return ret;
 }
@@ -788,7 +734,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 	lo->lo_device = bdev;
 	lo->lo_flags = lo_flags;
 	lo->lo_backing_file = file;
-	lo->transfer = transfer_none;
+	lo->transfer = NULL;
 	lo->ioctl = NULL;
 	lo->lo_sizelimit = 0;
 	lo->old_gfp_mask = mapping_gfp_mask(mapping);
@@ -1007,7 +953,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 		memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
 		       info->lo_encrypt_key_size);
 		lo->lo_key_owner = uid;
-	}	
+	}
 
 	return 0;
 }
diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c
index 91442fab5725..c6c824356464 100644
--- a/drivers/staging/lustre/lustre/llite/rw26.c
+++ b/drivers/staging/lustre/lustre/llite/rw26.c
@@ -359,8 +359,8 @@ static ssize_t ll_direct_IO_26_seg(const struct lu_env *env, struct cl_io *io,
  * up to 22MB for 128kB kmalloc and up to 682MB for 4MB kmalloc. */
 #define MAX_DIO_SIZE ((MAX_MALLOC / sizeof(struct brw_page) * PAGE_CACHE_SIZE) & \
 		      ~(DT_MAX_BRW_SIZE - 1))
-static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
-			       struct iov_iter *iter, loff_t file_offset)
+static ssize_t ll_direct_IO_26(struct kiocb *iocb, struct iov_iter *iter,
+			       loff_t file_offset)
 {
 	struct lu_env *env;
 	struct cl_io *io;
@@ -399,7 +399,7 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
 	 *    size changing by concurrent truncates and writes.
 	 * 1. Need inode mutex to operate transient pages.
 	 */
-	if (rw == READ)
+	if (iov_iter_rw(iter) == READ)
 		mutex_lock(&inode->i_mutex);
 
 	LASSERT(obj->cob_transient_pages == 0);
@@ -408,7 +408,7 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
 		size_t offs;
 
 		count = min_t(size_t, iov_iter_count(iter), size);
-		if (rw == READ) {
+		if (iov_iter_rw(iter) == READ) {
 			if (file_offset >= i_size_read(inode))
 				break;
 			if (file_offset + count > i_size_read(inode))
@@ -418,11 +418,11 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
 		result = iov_iter_get_pages_alloc(iter, &pages, count, &offs);
 		if (likely(result > 0)) {
 			int n = DIV_ROUND_UP(result + offs, PAGE_SIZE);
-			result = ll_direct_IO_26_seg(env, io, rw, inode,
-						     file->f_mapping,
-						     result, file_offset,
-						     pages, n);
-			ll_free_user_pages(pages, n, rw==READ);
+			result = ll_direct_IO_26_seg(env, io, iov_iter_rw(iter),
+						     inode, file->f_mapping,
+						     result, file_offset, pages,
+						     n);
+			ll_free_user_pages(pages, n, iov_iter_rw(iter) == READ);
 		}
 		if (unlikely(result <= 0)) {
 			/* If we can't allocate a large enough buffer
@@ -449,11 +449,11 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
 	}
 out:
 	LASSERT(obj->cob_transient_pages == 0);
-	if (rw == READ)
+	if (iov_iter_rw(iter) == READ)
 		mutex_unlock(&inode->i_mutex);
 
 	if (tot_bytes > 0) {
-		if (rw == WRITE) {
+		if (iov_iter_rw(iter) == WRITE) {
 			struct lov_stripe_md *lsm;
 
 			lsm = ccc_inode_lsm_get(inode);
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 2e38f9a5b472..be35d05a4d0e 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -230,7 +230,6 @@ static int v9fs_launder_page(struct page *page)
 
 /**
  * v9fs_direct_IO - 9P address space operation for direct I/O
- * @rw: direction (read or write)
  * @iocb: target I/O control block
  * @iov: array of vectors that define I/O buffer
  * @pos: offset in file to begin the operation
@@ -248,12 +247,12 @@ static int v9fs_launder_page(struct page *page)
  *
  */
 static ssize_t
-v9fs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
+v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
 {
 	struct file *file = iocb->ki_filp;
 	ssize_t n;
 	int err = 0;
-	if (rw & WRITE) {
+	if (iov_iter_rw(iter) == WRITE) {
 		n = p9_client_write(file->private_data, pos, iter, &err);
 		if (n) {
 			struct inode *inode = file_inode(file);
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index d7fcb775311e..2a9dd37dc426 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -404,21 +404,16 @@ static ssize_t
 v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
-	ssize_t retval = 0;
-	loff_t origin = iocb->ki_pos;
-	size_t count = iov_iter_count(from);
+	ssize_t retval;
+	loff_t origin;
 	int err = 0;
 
-	retval = generic_write_checks(file, &origin, &count, 0);
-	if (retval)
+	retval = generic_write_checks(iocb, from);
+	if (retval <= 0)
 		return retval;
 
-	iov_iter_truncate(from, count);
-
-	if (!count)
-		return 0;
-
-	retval = p9_client_write(file->private_data, origin, from, &err);
+	origin = iocb->ki_pos;
+	retval = p9_client_write(file->private_data, iocb->ki_pos, from, &err);
 	if (retval > 0) {
 		struct inode *inode = file_inode(file);
 		loff_t i_size;
@@ -428,12 +423,11 @@ v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		if (inode->i_mapping && inode->i_mapping->nrpages)
 			invalidate_inode_pages2_range(inode->i_mapping,
 						      pg_start, pg_end);
-		origin += retval;
+		iocb->ki_pos += retval;
 		i_size = i_size_read(inode);
-		iocb->ki_pos = origin;
-		if (origin > i_size) {
-			inode_add_bytes(inode, origin - i_size);
-			i_size_write(inode, origin);
+		if (iocb->ki_pos > i_size) {
+			inode_add_bytes(inode, iocb->ki_pos - i_size);
+			i_size_write(inode, iocb->ki_pos);
 		}
 		return retval;
 	}
diff --git a/fs/affs/file.c b/fs/affs/file.c
index 7c1a3d4c19c2..dcf27951781c 100644
--- a/fs/affs/file.c
+++ b/fs/affs/file.c
@@ -389,8 +389,7 @@ static void affs_write_failed(struct address_space *mapping, loff_t to)
 }
 
 static ssize_t
-affs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
-	       loff_t offset)
+affs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -398,15 +397,15 @@ affs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	if (rw == WRITE) {
+	if (iov_iter_rw(iter) == WRITE) {
 		loff_t size = offset + count;
 
 		if (AFFS_I(inode)->mmu_private < size)
 			return 0;
 	}
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, affs_get_block);
-	if (ret < 0 && (rw & WRITE))
+	ret = blockdev_direct_IO(iocb, inode, iter, offset, affs_get_block);
+	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 		affs_write_failed(mapping, offset + count);
 	return ret;
 }
diff --git a/fs/aio.c b/fs/aio.c
index fa8b16f47f1a..480440f4701f 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1517,7 +1517,7 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
 	}
 	req->common.ki_pos = iocb->aio_offset;
 	req->common.ki_complete = aio_complete;
-	req->common.ki_flags = 0;
+	req->common.ki_flags = iocb_flags(req->common.ki_filp);
 
 	if (iocb->aio_flags & IOCB_FLAG_RESFD) {
 		/*
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b5e87896f517..897ee0503932 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -146,15 +146,13 @@ blkdev_get_block(struct inode *inode, sector_t iblock,
 }
 
 static ssize_t
-blkdev_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
-			loff_t offset)
+blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 
-	return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iter,
-				    offset, blkdev_get_block,
-				    NULL, NULL, 0);
+	return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset,
+				    blkdev_get_block, NULL, NULL, 0);
 }
 
 int __sync_blockdev(struct block_device *bdev, int wait)
@@ -1597,9 +1595,22 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
+	struct inode *bd_inode = file->f_mapping->host;
+	loff_t size = i_size_read(bd_inode);
 	struct blk_plug plug;
 	ssize_t ret;
 
+	if (bdev_read_only(I_BDEV(bd_inode)))
+		return -EPERM;
+
+	if (!iov_iter_count(from))
+		return 0;
+
+	if (iocb->ki_pos >= size)
+		return -ENOSPC;
+
+	iov_iter_truncate(from, size - iocb->ki_pos);
+
 	blk_start_plug(&plug);
 	ret = __generic_file_write_iter(iocb, from);
 	if (ret > 0) {
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index cdc801c85105..faa7d390841b 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1739,27 +1739,19 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	u64 start_pos;
 	u64 end_pos;
 	ssize_t num_written = 0;
-	ssize_t err = 0;
-	size_t count = iov_iter_count(from);
 	bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
-	loff_t pos = iocb->ki_pos;
+	ssize_t err;
+	loff_t pos;
+	size_t count;
 
 	mutex_lock(&inode->i_mutex);
-
-	current->backing_dev_info = inode_to_bdi(inode);
-	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
-	if (err) {
+	err = generic_write_checks(iocb, from);
+	if (err <= 0) {
 		mutex_unlock(&inode->i_mutex);
-		goto out;
-	}
-
-	if (count == 0) {
-		mutex_unlock(&inode->i_mutex);
-		goto out;
+		return err;
 	}
 
-	iov_iter_truncate(from, count);
-
+	current->backing_dev_info = inode_to_bdi(inode);
 	err = file_remove_suid(file);
 	if (err) {
 		mutex_unlock(&inode->i_mutex);
@@ -1786,6 +1778,8 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	 */
 	update_time_for_write(inode);
 
+	pos = iocb->ki_pos;
+	count = iov_iter_count(from);
 	start_pos = round_down(pos, root->sectorsize);
 	if (start_pos > i_size_read(inode)) {
 		/* Expand hole size to cover write data, preventing empty gap */
@@ -1800,7 +1794,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	if (sync)
 		atomic_inc(&BTRFS_I(inode)->sync_writers);
 
-	if (file->f_flags & O_DIRECT) {
+	if (iocb->ki_flags & IOCB_DIRECT) {
 		num_written = __btrfs_direct_write(iocb, from, pos);
 	} else {
 		num_written = __btrfs_buffered_write(file, from, pos);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 686331f22b15..43192e10cc43 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8081,7 +8081,7 @@ free_ordered:
 	bio_endio(dio_bio, ret);
 }
 
-static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
+static ssize_t check_direct_IO(struct btrfs_root *root, struct kiocb *iocb,
 			const struct iov_iter *iter, loff_t offset)
 {
 	int seg;
@@ -8096,7 +8096,7 @@ static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *io
 		goto out;
 
 	/* If this is a write we don't need to check anymore */
-	if (rw & WRITE)
+	if (iov_iter_rw(iter) == WRITE)
 		return 0;
 	/*
 	 * Check to make sure we don't have duplicate iov_base's in this
@@ -8114,8 +8114,8 @@ out:
 	return retval;
 }
 
-static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
-			struct iov_iter *iter, loff_t offset)
+static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			       loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -8126,7 +8126,7 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 	bool relock = false;
 	ssize_t ret;
 
-	if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iter, offset))
+	if (check_direct_IO(BTRFS_I(inode)->root, iocb, iter, offset))
 		return 0;
 
 	atomic_inc(&inode->i_dio_count);
@@ -8144,7 +8144,7 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 		filemap_fdatawrite_range(inode->i_mapping, offset,
 					 offset + count - 1);
 
-	if (rw & WRITE) {
+	if (iov_iter_rw(iter) == WRITE) {
 		/*
 		 * If the write DIO is beyond the EOF, we need update
 		 * the isize, but it is protected by i_mutex. So we can
@@ -8174,11 +8174,11 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 		wakeup = false;
 	}
 
-	ret = __blockdev_direct_IO(rw, iocb, inode,
-			BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
-			iter, offset, btrfs_get_blocks_direct, NULL,
-			btrfs_submit_direct, flags);
-	if (rw & WRITE) {
+	ret = __blockdev_direct_IO(iocb, inode,
+				   BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
+				   iter, offset, btrfs_get_blocks_direct, NULL,
+				   btrfs_submit_direct, flags);
+	if (iov_iter_rw(iter) == WRITE) {
 		current->journal_info = NULL;
 		if (ret < 0 && ret != -EIOCBQUEUED)
 			btrfs_delalloc_release_space(inode, count);
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index fd5599d32362..155ab9c0246b 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1198,8 +1198,7 @@ static int ceph_write_end(struct file *file, struct address_space *mapping,
  * intercept O_DIRECT reads and writes early, this function should
  * never get called.
  */
-static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
-			      struct iov_iter *iter,
+static ssize_t ceph_direct_io(struct kiocb *iocb, struct iov_iter *iter,
 			      loff_t pos)
 {
 	WARN_ON(1);
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 56237ea5fc22..b9b8eb225f66 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -457,7 +457,7 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i,
 	if (ret < 0)
 		return ret;
 
-	if (file->f_flags & O_DIRECT) {
+	if (iocb->ki_flags & IOCB_DIRECT) {
 		while (iov_iter_count(i)) {
 			size_t start;
 			ssize_t n;
@@ -828,7 +828,7 @@ again:
 		return ret;
 
 	if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
-	    (iocb->ki_filp->f_flags & O_DIRECT) ||
+	    (iocb->ki_flags & IOCB_DIRECT) ||
 	    (fi->flags & CEPH_F_SYNC)) {
 
 		dout("aio_sync_read %p %llx.%llx %llu~%u got cap refs on %s\n",
@@ -941,9 +941,9 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_osd_client *osdc =
 		&ceph_sb_to_client(inode->i_sb)->client->osdc;
-	ssize_t count = iov_iter_count(from), written = 0;
+	ssize_t count, written = 0;
 	int err, want, got;
-	loff_t pos = iocb->ki_pos;
+	loff_t pos;
 
 	if (ceph_snap(inode) != CEPH_NOSNAP)
 		return -EROFS;
@@ -953,14 +953,12 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
 
-	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
-	if (err)
-		goto out;
-
-	if (count == 0)
+	err = generic_write_checks(iocb, from);
+	if (err <= 0)
 		goto out;
-	iov_iter_truncate(from, count);
 
+	pos = iocb->ki_pos;
+	count = iov_iter_count(from);
 	err = file_remove_suid(file);
 	if (err)
 		goto out;
@@ -997,12 +995,12 @@ retry_snap:
 	     inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
 
 	if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
-	    (file->f_flags & O_DIRECT) || (fi->flags & CEPH_F_SYNC)) {
+	    (iocb->ki_flags & IOCB_DIRECT) || (fi->flags & CEPH_F_SYNC)) {
 		struct iov_iter data;
 		mutex_unlock(&inode->i_mutex);
 		/* we might need to revert back to that point */
 		data = *from;
-		if (file->f_flags & O_DIRECT)
+		if (iocb->ki_flags & IOCB_DIRECT)
 			written = ceph_sync_direct_write(iocb, &data, pos);
 		else
 			written = ceph_sync_write(iocb, &data, pos);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index ca30c391a894..ca2bc5406306 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2560,10 +2560,9 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
 	return rc;
 }
 
-static ssize_t
-cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
+ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
 {
-	size_t len;
+	struct file *file = iocb->ki_filp;
 	ssize_t total_written = 0;
 	struct cifsFileInfo *open_file;
 	struct cifs_tcon *tcon;
@@ -2573,15 +2572,15 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
 	struct iov_iter saved_from;
 	int rc;
 
-	len = iov_iter_count(from);
-	rc = generic_write_checks(file, poffset, &len, 0);
-	if (rc)
-		return rc;
-
-	if (!len)
-		return 0;
+	/*
+	 * BB - optimize the way when signing is disabled. We can drop this
+	 * extra memory-to-memory copying and use iovec buffers for constructing
+	 * write request.
+	 */
 
-	iov_iter_truncate(from, len);
+	rc = generic_write_checks(iocb, from);
+	if (rc <= 0)
+		return rc;
 
 	INIT_LIST_HEAD(&wdata_list);
 	cifs_sb = CIFS_FILE_SB(file);
@@ -2593,8 +2592,8 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
 
 	memcpy(&saved_from, from, sizeof(struct iov_iter));
 
-	rc = cifs_write_from_iter(*poffset, len, from, open_file, cifs_sb,
-				  &wdata_list);
+	rc = cifs_write_from_iter(iocb->ki_pos, iov_iter_count(from), from,
+				  open_file, cifs_sb, &wdata_list);
 
 	/*
 	 * If at least one write was successfully sent, then discard any rc
@@ -2633,7 +2632,7 @@ restart_loop:
 				memcpy(&tmp_from, &saved_from,
 				       sizeof(struct iov_iter));
 				iov_iter_advance(&tmp_from,
-						 wdata->offset - *poffset);
+						 wdata->offset - iocb->ki_pos);
 
 				rc = cifs_write_from_iter(wdata->offset,
 						wdata->bytes, &tmp_from,
@@ -2650,34 +2649,13 @@ restart_loop:
 		kref_put(&wdata->refcount, cifs_uncached_writedata_release);
 	}
 
-	if (total_written > 0)
-		*poffset += total_written;
+	if (unlikely(!total_written))
+		return rc;
 
+	iocb->ki_pos += total_written;
+	set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(file_inode(file))->flags);
 	cifs_stats_bytes_written(tcon, total_written);
-	return total_written ? total_written : (ssize_t)rc;
-}
-
-ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
-{
-	ssize_t written;
-	struct inode *inode;
-	loff_t pos = iocb->ki_pos;
-
-	inode = file_inode(iocb->ki_filp);
-
-	/*
-	 * BB - optimize the way when signing is disabled. We can drop this
-	 * extra memory-to-memory copying and use iovec buffers for constructing
-	 * write request.
-	 */
-
-	written = cifs_iovec_write(iocb->ki_filp, from, &pos);
-	if (written > 0) {
-		set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(inode)->flags);
-		iocb->ki_pos = pos;
-	}
-
-	return written;
+	return total_written;
 }
 
 static ssize_t
@@ -2688,8 +2666,7 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 	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 = -EACCES;
-	loff_t lock_pos = iocb->ki_pos;
+	ssize_t rc;
 
 	/*
 	 * We need to hold the sem to be sure nobody modifies lock list
@@ -2697,23 +2674,24 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 	 */
 	down_read(&cinode->lock_sem);
 	mutex_lock(&inode->i_mutex);
-	if (file->f_flags & O_APPEND)
-		lock_pos = i_size_read(inode);
-	if (!cifs_find_lock_conflict(cfile, lock_pos, iov_iter_count(from),
+
+	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, NULL,
-				     CIFS_WRITE_OP)) {
+				     CIFS_WRITE_OP))
 		rc = __generic_file_write_iter(iocb, from);
-		mutex_unlock(&inode->i_mutex);
-
-		if (rc > 0) {
-			ssize_t err;
+	else
+		rc = -EACCES;
+out:
+	mutex_unlock(&inode->i_mutex);
 
-			err = generic_write_sync(file, iocb->ki_pos - rc, rc);
-			if (err < 0)
-				rc = err;
-		}
-	} else {
-		mutex_unlock(&inode->i_mutex);
+	if (rc > 0) {
+		ssize_t err = generic_write_sync(file, iocb->ki_pos - rc, rc);
+		if (err < 0)
+			rc = err;
 	}
 	up_read(&cinode->lock_sem);
 	return rc;
@@ -3877,8 +3855,7 @@ void cifs_oplock_break(struct work_struct *work)
  * Direct IO is not yet supported in the cached mode. 
  */
 static ssize_t
-cifs_direct_io(int rw, struct kiocb *iocb, struct iov_iter *iter,
-               loff_t pos)
+cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
 {
         /*
          * FIXME
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index cf0db005d2f5..acb3d63bc9dc 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1598,7 +1598,7 @@ static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
 			if (offset >= 0)
 				break;
 		default:
-			mutex_unlock(&file_inode(file)->i_mutex);
+			mutex_unlock(&dentry->d_inode->i_mutex);
 			return -EINVAL;
 	}
 	if (offset != file->f_pos) {
diff --git a/fs/dax.c b/fs/dax.c
index d0bd1f4f81b3..0bb0aecb556c 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -98,9 +98,9 @@ static bool buffer_size_valid(struct buffer_head *bh)
 	return bh->b_state != 0;
 }
 
-static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
-			loff_t start, loff_t end, get_block_t get_block,
-			struct buffer_head *bh)
+static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
+		      loff_t start, loff_t end, get_block_t get_block,
+		      struct buffer_head *bh)
 {
 	ssize_t retval = 0;
 	loff_t pos = start;
@@ -109,7 +109,7 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
 	void *addr;
 	bool hole = false;
 
-	if (rw != WRITE)
+	if (iov_iter_rw(iter) != WRITE)
 		end = min(end, i_size_read(inode));
 
 	while (pos < end) {
@@ -124,7 +124,7 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
 				bh->b_size = PAGE_ALIGN(end - pos);
 				bh->b_state = 0;
 				retval = get_block(inode, block, bh,
-								rw == WRITE);
+						   iov_iter_rw(iter) == WRITE);
 				if (retval)
 					break;
 				if (!buffer_size_valid(bh))
@@ -137,7 +137,7 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
 				bh->b_size -= done;
 			}
 
-			hole = (rw != WRITE) && !buffer_written(bh);
+			hole = iov_iter_rw(iter) != WRITE && !buffer_written(bh);
 			if (hole) {
 				addr = NULL;
 				size = bh->b_size - first;
@@ -154,7 +154,7 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
 			max = min(pos + size, end);
 		}
 
-		if (rw == WRITE)
+		if (iov_iter_rw(iter) == WRITE)
 			len = copy_from_iter(addr, max - pos, iter);
 		else if (!hole)
 			len = copy_to_iter(addr, max - pos, iter);
@@ -173,7 +173,6 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
 
 /**
  * dax_do_io - Perform I/O to a DAX file
- * @rw: READ to read or WRITE to write
  * @iocb: The control block for this I/O
  * @inode: The file which the I/O is directed at
  * @iter: The addresses to do I/O from or to
@@ -189,9 +188,9 @@ static ssize_t dax_io(int rw, struct inode *inode, struct iov_iter *iter,
  * As with do_blockdev_direct_IO(), we increment i_dio_count while the I/O
  * is in progress.
  */
-ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
-			struct iov_iter *iter, loff_t pos,
-			get_block_t get_block, dio_iodone_t end_io, int flags)
+ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
+		  struct iov_iter *iter, loff_t pos, get_block_t get_block,
+		  dio_iodone_t end_io, int flags)
 {
 	struct buffer_head bh;
 	ssize_t retval = -EINVAL;
@@ -199,7 +198,7 @@ ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
 
 	memset(&bh, 0, sizeof(bh));
 
-	if ((flags & DIO_LOCKING) && (rw == READ)) {
+	if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ) {
 		struct address_space *mapping = inode->i_mapping;
 		mutex_lock(&inode->i_mutex);
 		retval = filemap_write_and_wait_range(mapping, pos, end - 1);
@@ -212,9 +211,9 @@ ssize_t dax_do_io(int rw, struct kiocb *iocb, struct inode *inode,
 	/* Protects against truncate */
 	atomic_inc(&inode->i_dio_count);
 
-	retval = dax_io(rw, inode, iter, pos, end, get_block, &bh);
+	retval = dax_io(inode, iter, pos, end, get_block, &bh);
 
-	if ((flags & DIO_LOCKING) && (rw == READ))
+	if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ)
 		mutex_unlock(&inode->i_mutex);
 
 	if ((retval > 0) && end_io)
diff --git a/fs/dcache.c b/fs/dcache.c
index d99736a63e3c..656ce522a218 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -269,6 +269,41 @@ static inline int dname_external(const struct dentry *dentry)
 	return dentry->d_name.name != dentry->d_iname;
 }
 
+/*
+ * Make sure other CPUs see the inode attached before the type is set.
+ */
+static inline void __d_set_inode_and_type(struct dentry *dentry,
+					  struct inode *inode,
+					  unsigned type_flags)
+{
+	unsigned flags;
+
+	dentry->d_inode = inode;
+	smp_wmb();
+	flags = READ_ONCE(dentry->d_flags);
+	flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
+	flags |= type_flags;
+	WRITE_ONCE(dentry->d_flags, flags);
+}
+
+/*
+ * Ideally, we want to make sure that other CPUs see the flags cleared before
+ * the inode is detached, but this is really a violation of RCU principles
+ * since the ordering suggests we should always set inode before flags.
+ *
+ * We should instead replace or discard the entire dentry - but that sucks
+ * performancewise on mass deletion/rename.
+ */
+static inline void __d_clear_type_and_inode(struct dentry *dentry)
+{
+	unsigned flags = READ_ONCE(dentry->d_flags);
+
+	flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
+	WRITE_ONCE(dentry->d_flags, flags);
+	smp_wmb();
+	dentry->d_inode = NULL;
+}
+
 static void dentry_free(struct dentry *dentry)
 {
 	WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
@@ -311,7 +346,7 @@ static void dentry_iput(struct dentry * dentry)
 {
 	struct inode *inode = dentry->d_inode;
 	if (inode) {
-		dentry->d_inode = NULL;
+		__d_clear_type_and_inode(dentry);
 		hlist_del_init(&dentry->d_u.d_alias);
 		spin_unlock(&dentry->d_lock);
 		spin_unlock(&inode->i_lock);
@@ -335,8 +370,7 @@ static void dentry_unlink_inode(struct dentry * dentry)
 	__releases(dentry->d_inode->i_lock)
 {
 	struct inode *inode = dentry->d_inode;
-	__d_clear_type(dentry);
-	dentry->d_inode = NULL;
+	__d_clear_type_and_inode(dentry);
 	hlist_del_init(&dentry->d_u.d_alias);
 	dentry_rcuwalk_barrier(dentry);
 	spin_unlock(&dentry->d_lock);
@@ -1715,11 +1749,9 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode)
 	unsigned add_flags = d_flags_for_inode(inode);
 
 	spin_lock(&dentry->d_lock);
-	dentry->d_flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU);
-	dentry->d_flags |= add_flags;
 	if (inode)
 		hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
-	dentry->d_inode = inode;
+	__d_set_inode_and_type(dentry, inode, add_flags);
 	dentry_rcuwalk_barrier(dentry);
 	spin_unlock(&dentry->d_lock);
 	fsnotify_d_instantiate(dentry, inode);
@@ -1937,8 +1969,7 @@ static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
 		add_flags |= DCACHE_DISCONNECTED;
 
 	spin_lock(&tmp->d_lock);
-	tmp->d_inode = inode;
-	tmp->d_flags |= add_flags;
+	__d_set_inode_and_type(tmp, inode, add_flags);
 	hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry);
 	hlist_bl_lock(&tmp->d_sb->s_anon);
 	hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 61e72d44cf94..c9ee0dfe90b5 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -524,7 +524,7 @@ static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
 
 	if (debugfs_positive(dentry)) {
 		dget(dentry);
-		if (S_ISDIR(dentry->d_inode->i_mode))
+		if (d_is_dir(dentry))
 			ret = simple_rmdir(parent->d_inode, dentry);
 		else
 			simple_unlink(parent->d_inode, dentry);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 6fb00e3f1059..c3b560b24a46 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1093,10 +1093,10 @@ static inline int drop_refcount(struct dio *dio)
  * for the whole file.
  */
 static inline ssize_t
-do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
-	struct block_device *bdev, struct iov_iter *iter, loff_t offset, 
-	get_block_t get_block, dio_iodone_t end_io,
-	dio_submit_t submit_io,	int flags)
+do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
+		      struct block_device *bdev, struct iov_iter *iter,
+		      loff_t offset, get_block_t get_block, dio_iodone_t end_io,
+		      dio_submit_t submit_io, int flags)
 {
 	unsigned i_blkbits = ACCESS_ONCE(inode->i_blkbits);
 	unsigned blkbits = i_blkbits;
@@ -1110,9 +1110,6 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	struct blk_plug plug;
 	unsigned long align = offset | iov_iter_alignment(iter);
 
-	if (rw & WRITE)
-		rw = WRITE_ODIRECT;
-
 	/*
 	 * Avoid references to bdev if not absolutely needed to give
 	 * the early prefetch in the caller enough time.
@@ -1127,7 +1124,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	}
 
 	/* watch out for a 0 len io from a tricksy fs */
-	if (rw == READ && !iov_iter_count(iter))
+	if (iov_iter_rw(iter) == READ && !iov_iter_count(iter))
 		return 0;
 
 	dio = kmem_cache_alloc(dio_cache, GFP_KERNEL);
@@ -1143,7 +1140,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 
 	dio->flags = flags;
 	if (dio->flags & DIO_LOCKING) {
-		if (rw == READ) {
+		if (iov_iter_rw(iter) == READ) {
 			struct address_space *mapping =
 					iocb->ki_filp->f_mapping;
 
@@ -1169,19 +1166,19 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	if (is_sync_kiocb(iocb))
 		dio->is_async = false;
 	else if (!(dio->flags & DIO_ASYNC_EXTEND) &&
-            (rw & WRITE) && end > i_size_read(inode))
+		 iov_iter_rw(iter) == WRITE && end > i_size_read(inode))
 		dio->is_async = false;
 	else
 		dio->is_async = true;
 
 	dio->inode = inode;
-	dio->rw = rw;
+	dio->rw = iov_iter_rw(iter) == WRITE ? WRITE_ODIRECT : READ;
 
 	/*
 	 * For AIO O_(D)SYNC writes we need to defer completions to a workqueue
 	 * so that we can call ->fsync.
 	 */
-	if (dio->is_async && (rw & WRITE) &&
+	if (dio->is_async && iov_iter_rw(iter) == WRITE &&
 	    ((iocb->ki_filp->f_flags & O_DSYNC) ||
 	     IS_SYNC(iocb->ki_filp->f_mapping->host))) {
 		retval = dio_set_defer_completion(dio);
@@ -1274,7 +1271,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	 * we can let i_mutex go now that its achieved its purpose
 	 * of protecting us from looking up uninitialized blocks.
 	 */
-	if (rw == READ && (dio->flags & DIO_LOCKING))
+	if (iov_iter_rw(iter) == READ && (dio->flags & DIO_LOCKING))
 		mutex_unlock(&dio->inode->i_mutex);
 
 	/*
@@ -1286,7 +1283,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	 */
 	BUG_ON(retval == -EIOCBQUEUED);
 	if (dio->is_async && retval == 0 && dio->result &&
-	    (rw == READ || dio->result == count))
+	    (iov_iter_rw(iter) == READ || dio->result == count))
 		retval = -EIOCBQUEUED;
 	else
 		dio_await_completion(dio);
@@ -1300,11 +1297,11 @@ out:
 	return retval;
 }
 
-ssize_t
-__blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
-	struct block_device *bdev, struct iov_iter *iter, loff_t offset,
-	get_block_t get_block, dio_iodone_t end_io,
-	dio_submit_t submit_io,	int flags)
+ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
+			     struct block_device *bdev, struct iov_iter *iter,
+			     loff_t offset, get_block_t get_block,
+			     dio_iodone_t end_io, dio_submit_t submit_io,
+			     int flags)
 {
 	/*
 	 * The block device state is needed in the end to finally
@@ -1318,8 +1315,8 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	prefetch(bdev->bd_queue);
 	prefetch((char *)bdev->bd_queue + SMP_CACHE_BYTES);
 
-	return do_blockdev_direct_IO(rw, iocb, inode, bdev, iter, offset,
-				     get_block, end_io, submit_io, flags);
+	return do_blockdev_direct_IO(iocb, inode, bdev, iter, offset, get_block,
+				     end_io, submit_io, flags);
 }
 
 EXPORT_SYMBOL(__blockdev_direct_IO);
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index a198e94813fe..35073aaec6e0 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -963,8 +963,8 @@ static void exofs_invalidatepage(struct page *page, unsigned int offset,
 
 
  /* TODO: Should be easy enough to do proprly */
-static ssize_t exofs_direct_IO(int rw, struct kiocb *iocb,
-		struct iov_iter *iter, loff_t offset)
+static ssize_t exofs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			       loff_t offset)
 {
 	return 0;
 }
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index b29eb6747116..5d9213963fae 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -851,8 +851,7 @@ static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
 }
 
 static ssize_t
-ext2_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
-			loff_t offset)
+ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -861,12 +860,12 @@ ext2_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 	ssize_t ret;
 
 	if (IS_DAX(inode))
-		ret = dax_do_io(rw, iocb, inode, iter, offset, ext2_get_block,
-				NULL, DIO_LOCKING);
+		ret = dax_do_io(iocb, inode, iter, offset, ext2_get_block, NULL,
+				DIO_LOCKING);
 	else
-		ret = blockdev_direct_IO(rw, iocb, inode, iter, offset,
+		ret = blockdev_direct_IO(iocb, inode, iter, offset,
 					 ext2_get_block);
-	if (ret < 0 && (rw & WRITE))
+	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 		ext2_write_failed(mapping, offset + count);
 	return ret;
 }
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index db07ffbe7c85..13c0868c7160 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1820,8 +1820,8 @@ static int ext3_releasepage(struct page *page, gfp_t wait)
  * crashes then stale disk data _may_ be exposed inside the file. But current
  * VFS code falls back into buffered path in that case so we are safe.
  */
-static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
-			struct iov_iter *iter, loff_t offset)
+static ssize_t ext3_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			      loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -1832,9 +1832,9 @@ static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
 	size_t count = iov_iter_count(iter);
 	int retries = 0;
 
-	trace_ext3_direct_IO_enter(inode, offset, count, rw);
+	trace_ext3_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 
-	if (rw == WRITE) {
+	if (iov_iter_rw(iter) == WRITE) {
 		loff_t final_size = offset + count;
 
 		if (final_size > inode->i_size) {
@@ -1856,12 +1856,12 @@ static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
 	}
 
 retry:
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, ext3_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, offset, ext3_get_block);
 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
-	if (unlikely((rw & WRITE) && ret < 0)) {
+	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
 		loff_t end = offset + count;
 
@@ -1908,7 +1908,7 @@ retry:
 			ret = err;
 	}
 out:
-	trace_ext3_direct_IO_exit(inode, offset, count, rw, ret);
+	trace_ext3_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
 	return ret;
 }
 
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8a3981ea35d8..c8eb32eefc3c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2152,8 +2152,8 @@ extern void ext4_da_update_reserve_space(struct inode *inode,
 /* indirect.c */
 extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
 				struct ext4_map_blocks *map, int flags);
-extern ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
-				struct iov_iter *iter, loff_t offset);
+extern ssize_t ext4_ind_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+				  loff_t offset);
 extern int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock);
 extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks);
 extern void ext4_ind_truncate(handle_t *, struct inode *inode);
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 7a6defcf3352..e576d682b353 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -95,11 +95,9 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct inode *inode = file_inode(iocb->ki_filp);
 	struct mutex *aio_mutex = NULL;
 	struct blk_plug plug;
-	int o_direct = io_is_direct(file);
+	int o_direct = iocb->ki_flags & IOCB_DIRECT;
 	int overwrite = 0;
-	size_t length = iov_iter_count(from);
 	ssize_t ret;
-	loff_t pos = iocb->ki_pos;
 
 	/*
 	 * Unaligned direct AIO must be serialized; see comment above
@@ -108,16 +106,17 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (o_direct &&
 	    ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
 	    !is_sync_kiocb(iocb) &&
-	    (file->f_flags & O_APPEND ||
-	     ext4_unaligned_aio(inode, from, pos))) {
+	    (iocb->ki_flags & IOCB_APPEND ||
+	     ext4_unaligned_aio(inode, from, iocb->ki_pos))) {
 		aio_mutex = ext4_aio_mutex(inode);
 		mutex_lock(aio_mutex);
 		ext4_unwritten_wait(inode);
 	}
 
 	mutex_lock(&inode->i_mutex);
-	if (file->f_flags & O_APPEND)
-		iocb->ki_pos = pos = i_size_read(inode);
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
 
 	/*
 	 * If we have encountered a bitmap-format file, the size limit
@@ -126,22 +125,19 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 
-		if ((pos > sbi->s_bitmap_maxbytes) ||
-		    (pos == sbi->s_bitmap_maxbytes && length > 0)) {
-			mutex_unlock(&inode->i_mutex);
+		if (iocb->ki_pos >= sbi->s_bitmap_maxbytes) {
 			ret = -EFBIG;
-			goto errout;
+			goto out;
 		}
-
-		if (pos + length > sbi->s_bitmap_maxbytes)
-			iov_iter_truncate(from, sbi->s_bitmap_maxbytes - pos);
+		iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
 	}
 
 	iocb->private = &overwrite;
 	if (o_direct) {
+		size_t length = iov_iter_count(from);
+		loff_t pos = iocb->ki_pos;
 		blk_start_plug(&plug);
 
-
 		/* check whether we do a DIO overwrite or not */
 		if (ext4_should_dioread_nolock(inode) && !aio_mutex &&
 		    !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
@@ -185,7 +181,12 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (o_direct)
 		blk_finish_plug(&plug);
 
-errout:
+	if (aio_mutex)
+		mutex_unlock(aio_mutex);
+	return ret;
+
+out:
+	mutex_unlock(&inode->i_mutex);
 	if (aio_mutex)
 		mutex_unlock(aio_mutex);
 	return ret;
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 740c7871c117..3580629e42d3 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -642,8 +642,8 @@ out:
  * crashes then stale disk data _may_ be exposed inside the file. But current
  * VFS code falls back into buffered path in that case so we are safe.
  */
-ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
-			   struct iov_iter *iter, loff_t offset)
+ssize_t ext4_ind_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			   loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -654,7 +654,7 @@ ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
 	size_t count = iov_iter_count(iter);
 	int retries = 0;
 
-	if (rw == WRITE) {
+	if (iov_iter_rw(iter) == WRITE) {
 		loff_t final_size = offset + count;
 
 		if (final_size > inode->i_size) {
@@ -676,7 +676,7 @@ ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
 	}
 
 retry:
-	if (rw == READ && ext4_should_dioread_nolock(inode)) {
+	if (iov_iter_rw(iter) == READ && ext4_should_dioread_nolock(inode)) {
 		/*
 		 * Nolock dioread optimization may be dynamically disabled
 		 * via ext4_inode_block_unlocked_dio(). Check inode's state
@@ -690,23 +690,24 @@ retry:
 			goto locked;
 		}
 		if (IS_DAX(inode))
-			ret = dax_do_io(rw, iocb, inode, iter, offset,
+			ret = dax_do_io(iocb, inode, iter, offset,
 					ext4_get_block, NULL, 0);
 		else
-			ret = __blockdev_direct_IO(rw, iocb, inode,
-					inode->i_sb->s_bdev, iter, offset,
-					ext4_get_block, NULL, NULL, 0);
+			ret = __blockdev_direct_IO(iocb, inode,
+						   inode->i_sb->s_bdev, iter,
+						   offset, ext4_get_block, NULL,
+						   NULL, 0);
 		inode_dio_done(inode);
 	} else {
 locked:
 		if (IS_DAX(inode))
-			ret = dax_do_io(rw, iocb, inode, iter, offset,
+			ret = dax_do_io(iocb, inode, iter, offset,
 					ext4_get_block, NULL, DIO_LOCKING);
 		else
-			ret = blockdev_direct_IO(rw, iocb, inode, iter,
-					offset, ext4_get_block);
+			ret = blockdev_direct_IO(iocb, inode, iter, offset,
+						 ext4_get_block);
 
-		if (unlikely((rw & WRITE) && ret < 0)) {
+		if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 			loff_t isize = i_size_read(inode);
 			loff_t end = offset + count;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 035b7a06f1c3..b49cf6e59953 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2952,8 +2952,8 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
  * if the machine crashes during the write.
  *
  */
-static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
-			      struct iov_iter *iter, loff_t offset)
+static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+				  loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -2966,8 +2966,8 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	ext4_io_end_t *io_end = NULL;
 
 	/* Use the old path for reads and writes beyond i_size. */
-	if (rw != WRITE || final_size > inode->i_size)
-		return ext4_ind_direct_IO(rw, iocb, iter, offset);
+	if (iov_iter_rw(iter) != WRITE || final_size > inode->i_size)
+		return ext4_ind_direct_IO(iocb, iter, offset);
 
 	BUG_ON(iocb->private == NULL);
 
@@ -2976,7 +2976,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	 * conversion. This also disallows race between truncate() and
 	 * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
 	 */
-	if (rw == WRITE)
+	if (iov_iter_rw(iter) == WRITE)
 		atomic_inc(&inode->i_dio_count);
 
 	/* If we do a overwrite dio, i_mutex locking can be released */
@@ -3034,10 +3034,10 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 		dio_flags = DIO_LOCKING;
 	}
 	if (IS_DAX(inode))
-		ret = dax_do_io(rw, iocb, inode, iter, offset, get_block_func,
+		ret = dax_do_io(iocb, inode, iter, offset, get_block_func,
 				ext4_end_io_dio, dio_flags);
 	else
-		ret = __blockdev_direct_IO(rw, iocb, inode,
+		ret = __blockdev_direct_IO(iocb, inode,
 					   inode->i_sb->s_bdev, iter, offset,
 					   get_block_func,
 					   ext4_end_io_dio, NULL, dio_flags);
@@ -3078,7 +3078,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	}
 
 retake_lock:
-	if (rw == WRITE)
+	if (iov_iter_rw(iter) == WRITE)
 		inode_dio_done(inode);
 	/* take i_mutex locking again if we do a ovewrite dio */
 	if (overwrite) {
@@ -3089,8 +3089,8 @@ retake_lock:
 	return ret;
 }
 
-static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
-			      struct iov_iter *iter, loff_t offset)
+static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			      loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -3107,12 +3107,12 @@ static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
 	if (ext4_has_inline_data(inode))
 		return 0;
 
-	trace_ext4_direct_IO_enter(inode, offset, count, rw);
+	trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-		ret = ext4_ext_direct_IO(rw, iocb, iter, offset);
+		ret = ext4_ext_direct_IO(iocb, iter, offset);
 	else
-		ret = ext4_ind_direct_IO(rw, iocb, iter, offset);
-	trace_ext4_direct_IO_exit(inode, offset, count, rw, ret);
+		ret = ext4_ind_direct_IO(iocb, iter, offset);
+	trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
 	return ret;
 }
 
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 497f8515d205..319eda511c4f 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1118,12 +1118,12 @@ static int f2fs_write_end(struct file *file,
 	return copied;
 }
 
-static int check_direct_IO(struct inode *inode, int rw,
-		struct iov_iter *iter, loff_t offset)
+static int check_direct_IO(struct inode *inode, struct iov_iter *iter,
+			   loff_t offset)
 {
 	unsigned blocksize_mask = inode->i_sb->s_blocksize - 1;
 
-	if (rw == READ)
+	if (iov_iter_rw(iter) == READ)
 		return 0;
 
 	if (offset & blocksize_mask)
@@ -1135,8 +1135,8 @@ static int check_direct_IO(struct inode *inode, int rw,
 	return 0;
 }
 
-static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
-		struct iov_iter *iter, loff_t offset)
+static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			      loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -1151,19 +1151,19 @@ static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
 			return err;
 	}
 
-	if (check_direct_IO(inode, rw, iter, offset))
+	if (check_direct_IO(inode, iter, offset))
 		return 0;
 
-	trace_f2fs_direct_IO_enter(inode, offset, count, rw);
+	trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 
-	if (rw & WRITE)
+	if (iov_iter_rw(iter) == WRITE)
 		__allocate_data_blocks(inode, offset, count);
 
-	err = blockdev_direct_IO(rw, iocb, inode, iter, offset, get_data_block);
-	if (err < 0 && (rw & WRITE))
+	err = blockdev_direct_IO(iocb, inode, iter, offset, get_data_block);
+	if (err < 0 && iov_iter_rw(iter) == WRITE)
 		f2fs_write_failed(mapping, offset + count);
 
-	trace_f2fs_direct_IO_exit(inode, offset, count, rw, err);
+	trace_f2fs_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), err);
 
 	return err;
 }
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 8521207de229..41b729933638 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -245,8 +245,7 @@ static int fat_write_end(struct file *file, struct address_space *mapping,
 	return err;
 }
 
-static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
-			     struct iov_iter *iter,
+static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 			     loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
@@ -255,7 +254,7 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	if (rw == WRITE) {
+	if (iov_iter_rw(iter) == WRITE) {
 		/*
 		 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
 		 * so we need to update the ->mmu_private to block boundary.
@@ -274,8 +273,8 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 	 * FAT need to use the DIO_LOCKING for avoiding the race
 	 * condition of fat_get_block() and ->truncate().
 	 */
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, fat_get_block);
-	if (ret < 0 && (rw & WRITE))
+	ret = blockdev_direct_IO(iocb, inode, iter, offset, fat_get_block);
+	if (ret < 0 && iov_iter_rw(iter) == WRITE)
 		fat_write_failed(mapping, offset + count);
 
 	return ret;
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index e1afdd7abf90..5ef05b5c4cff 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1145,13 +1145,11 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
-	size_t count = iov_iter_count(from);
 	ssize_t written = 0;
 	ssize_t written_buffered = 0;
 	struct inode *inode = mapping->host;
 	ssize_t err;
 	loff_t endbyte = 0;
-	loff_t pos = iocb->ki_pos;
 
 	if (get_fuse_conn(inode)->writeback_cache) {
 		/* Update size (EOF optimization) and mode (SUID clearing) */
@@ -1167,14 +1165,10 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
 
-	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
-	if (err)
-		goto out;
-
-	if (count == 0)
+	err = generic_write_checks(iocb, from);
+	if (err <= 0)
 		goto out;
 
-	iov_iter_truncate(from, count);
 	err = file_remove_suid(file);
 	if (err)
 		goto out;
@@ -1183,7 +1177,8 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (err)
 		goto out;
 
-	if (file->f_flags & O_DIRECT) {
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		loff_t pos = iocb->ki_pos;
 		written = generic_file_direct_write(iocb, from, pos);
 		if (written < 0 || !iov_iter_count(from))
 			goto out;
@@ -1209,9 +1204,9 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		written += written_buffered;
 		iocb->ki_pos = pos + written_buffered;
 	} else {
-		written = fuse_perform_write(file, mapping, from, pos);
+		written = fuse_perform_write(file, mapping, from, iocb->ki_pos);
 		if (written >= 0)
-			iocb->ki_pos = pos + written;
+			iocb->ki_pos += written;
 	}
 out:
 	current->backing_dev_info = NULL;
@@ -1412,7 +1407,6 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
 	struct fuse_io_priv io = { .async = 0, .file = file };
-	size_t count = iov_iter_count(from);
 	ssize_t res;
 
 	if (is_bad_inode(inode))
@@ -1420,11 +1414,9 @@ static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 	/* Don't allow parallel writes to the same file */
 	mutex_lock(&inode->i_mutex);
-	res = generic_write_checks(file, &iocb->ki_pos, &count, 0);
-	if (!res) {
-		iov_iter_truncate(from, count);
+	res = generic_write_checks(iocb, from);
+	if (res > 0)
 		res = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE);
-	}
 	fuse_invalidate_attr(inode);
 	if (res > 0)
 		fuse_write_update_size(inode, iocb->ki_pos);
@@ -2782,8 +2774,7 @@ static inline loff_t fuse_round_up(loff_t off)
 }
 
 static ssize_t
-fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
-			loff_t offset)
+fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 {
 	DECLARE_COMPLETION_ONSTACK(wait);
 	ssize_t ret = 0;
@@ -2800,15 +2791,15 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 	inode = file->f_mapping->host;
 	i_size = i_size_read(inode);
 
-	if ((rw == READ) && (offset > i_size))
+	if ((iov_iter_rw(iter) == READ) && (offset > i_size))
 		return 0;
 
 	/* optimization for short read */
-	if (async_dio && rw != WRITE && offset + count > i_size) {
+	if (async_dio && iov_iter_rw(iter) != WRITE && offset + count > i_size) {
 		if (offset >= i_size)
 			return 0;
-		count = min_t(loff_t, count, fuse_round_up(i_size - offset));
-		iov_iter_truncate(iter, count);
+		iov_iter_truncate(iter, fuse_round_up(i_size - offset));
+		count = iov_iter_count(iter);
 	}
 
 	io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
@@ -2819,7 +2810,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 	io->bytes = -1;
 	io->size = 0;
 	io->offset = offset;
-	io->write = (rw == WRITE);
+	io->write = (iov_iter_rw(iter) == WRITE);
 	io->err = 0;
 	io->file = file;
 	/*
@@ -2834,19 +2825,15 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 	 * to wait on real async I/O requests, so we must submit this request
 	 * synchronously.
 	 */
-	if (!is_sync_kiocb(iocb) && (offset + count > i_size) && rw == WRITE)
+	if (!is_sync_kiocb(iocb) && (offset + count > i_size) &&
+	    iov_iter_rw(iter) == WRITE)
 		io->async = false;
 
 	if (io->async && is_sync_kiocb(iocb))
 		io->done = &wait;
 
-	if (rw == WRITE) {
-		ret = generic_write_checks(file, &pos, &count, 0);
-		if (!ret) {
-			iov_iter_truncate(iter, count);
-			ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
-		}
-
+	if (iov_iter_rw(iter) == WRITE) {
+		ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
 		fuse_invalidate_attr(inode);
 	} else {
 		ret = __fuse_direct_read(io, iter, &pos);
@@ -2865,7 +2852,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 
 	kfree(io);
 
-	if (rw == WRITE) {
+	if (iov_iter_rw(iter) == WRITE) {
 		if (ret > 0)
 			fuse_write_update_size(inode, pos);
 		else if (ret < 0 && offset + count > i_size)
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index a6e6990aea39..5551fea0afd7 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -1016,13 +1016,12 @@ out:
 /**
  * gfs2_ok_for_dio - check that dio is valid on this file
  * @ip: The inode
- * @rw: READ or WRITE
  * @offset: The offset at which we are reading or writing
  *
  * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
  *          1 (to accept the i/o request)
  */
-static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
+static int gfs2_ok_for_dio(struct gfs2_inode *ip, loff_t offset)
 {
 	/*
 	 * Should we return an error here? I can't see that O_DIRECT for
@@ -1039,8 +1038,8 @@ static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
 
 
 
-static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
-			      struct iov_iter *iter, loff_t offset)
+static ssize_t gfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			      loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
@@ -1061,7 +1060,7 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 	rv = gfs2_glock_nq(&gh);
 	if (rv)
 		return rv;
-	rv = gfs2_ok_for_dio(ip, rw, offset);
+	rv = gfs2_ok_for_dio(ip, offset);
 	if (rv != 1)
 		goto out; /* dio not valid, fall back to buffered i/o */
 
@@ -1091,13 +1090,12 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 		rv = filemap_write_and_wait_range(mapping, lstart, end);
 		if (rv)
 			goto out;
-		if (rw == WRITE)
+		if (iov_iter_rw(iter) == WRITE)
 			truncate_inode_pages_range(mapping, lstart, end);
 	}
 
-	rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev,
-				  iter, offset,
-				  gfs2_get_block_direct, NULL, NULL, 0);
+	rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
+				  offset, gfs2_get_block_direct, NULL, NULL, 0);
 out:
 	gfs2_glock_dq(&gh);
 	gfs2_holder_uninit(&gh);
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 207eb4a8135e..31892871ea87 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -709,7 +709,7 @@ static ssize_t gfs2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 	gfs2_size_hint(file, iocb->ki_pos, iov_iter_count(from));
 
-	if (file->f_flags & O_APPEND) {
+	if (iocb->ki_flags & IOCB_APPEND) {
 		struct gfs2_holder gh;
 
 		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 9337065bcc67..75fd5d873c19 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -124,8 +124,8 @@ static int hfs_releasepage(struct page *page, gfp_t mask)
 	return res ? try_to_free_buffers(page) : 0;
 }
 
-static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
-		struct iov_iter *iter, loff_t offset)
+static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			     loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -133,13 +133,13 @@ static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, hfs_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, offset, hfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
-	if (unlikely((rw & WRITE) && ret < 0)) {
+	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
 		loff_t end = offset + count;
 
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 5f86cadb0542..a43811f90935 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -122,8 +122,8 @@ static int hfsplus_releasepage(struct page *page, gfp_t mask)
 	return res ? try_to_free_buffers(page) : 0;
 }
 
-static ssize_t hfsplus_direct_IO(int rw, struct kiocb *iocb,
-		struct iov_iter *iter, loff_t offset)
+static ssize_t hfsplus_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+				 loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -131,14 +131,13 @@ static ssize_t hfsplus_direct_IO(int rw, struct kiocb *iocb,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, 
-				 hfsplus_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, offset, hfsplus_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
-	if (unlikely((rw & WRITE) && ret < 0)) {
+	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
 		loff_t end = offset + count;
 
diff --git a/fs/jfs/inode.c b/fs/jfs/inode.c
index 3197aed10614..070dc4b33544 100644
--- a/fs/jfs/inode.c
+++ b/fs/jfs/inode.c
@@ -330,8 +330,8 @@ static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
 	return generic_block_bmap(mapping, block, jfs_get_block);
 }
 
-static ssize_t jfs_direct_IO(int rw, struct kiocb *iocb,
-	struct iov_iter *iter, loff_t offset)
+static ssize_t jfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			     loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -339,13 +339,13 @@ static ssize_t jfs_direct_IO(int rw, struct kiocb *iocb,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, jfs_get_block);
+	ret = blockdev_direct_IO(iocb, inode, iter, offset, jfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
-	if (unlikely((rw & WRITE) && ret < 0)) {
+	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
 		loff_t end = offset + count;
 
diff --git a/fs/namei.c b/fs/namei.c
index 76fb76a0818b..ffab2e06e147 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1585,7 +1585,7 @@ static inline int walk_component(struct nameidata *nd, struct path *path,
 		inode = path->dentry->d_inode;
 	}
 	err = -ENOENT;
-	if (!inode || d_is_negative(path->dentry))
+	if (d_is_negative(path->dentry))
 		goto out_path_put;
 
 	if (should_follow_link(path->dentry, follow)) {
@@ -2310,7 +2310,7 @@ mountpoint_last(struct nameidata *nd, struct path *path)
 	mutex_unlock(&dir->d_inode->i_mutex);
 
 done:
-	if (!dentry->d_inode || d_is_negative(dentry)) {
+	if (d_is_negative(dentry)) {
 		error = -ENOENT;
 		dput(dentry);
 		goto out;
@@ -3038,7 +3038,7 @@ retry_lookup:
 finish_lookup:
 	/* we _can_ be in RCU mode here */
 	error = -ENOENT;
-	if (!inode || d_is_negative(path->dentry)) {
+	if (d_is_negative(path->dentry)) {
 		path_to_nameidata(path, nd);
 		goto out;
 	}
@@ -3077,7 +3077,7 @@ finish_open:
 	error = -ENOTDIR;
 	if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
 		goto out;
-	if (!S_ISREG(nd->inode->i_mode))
+	if (!d_is_reg(nd->path.dentry))
 		will_truncate = false;
 
 	if (will_truncate) {
diff --git a/fs/ncpfs/file.c b/fs/ncpfs/file.c
index 479bf8db264e..011324ce9df2 100644
--- a/fs/ncpfs/file.c
+++ b/fs/ncpfs/file.c
@@ -170,20 +170,15 @@ ncp_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
 	size_t already_written = 0;
-	loff_t pos = iocb->ki_pos;
-	size_t count = iov_iter_count(from);
 	size_t bufsize;
 	int errno;
 	void *bouncebuffer;
+	off_t pos;
 
 	ncp_dbg(1, "enter %pD2\n", file);
-	errno = generic_write_checks(file, &pos, &count, 0);
-	if (errno)
+	errno = generic_write_checks(iocb, from);
+	if (errno <= 0)
 		return errno;
-	iov_iter_truncate(from, count);
-	
-	if (!count)
-		return 0;
 
 	errno = ncp_make_open(inode, O_WRONLY);
 	if (errno) {
@@ -201,10 +196,11 @@ ncp_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		errno = -EIO;	/* -ENOMEM */
 		goto outrel;
 	}
+	pos = iocb->ki_pos;
 	while (iov_iter_count(from)) {
 		int written_this_time;
 		size_t to_write = min_t(size_t,
-				      bufsize - ((off_t)pos % bufsize),
+				      bufsize - (pos % bufsize),
 				      iov_iter_count(from));
 
 		if (copy_from_iter(bouncebuffer, to_write, from) != to_write) {
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index c3929fb2ab26..682f65fe09b5 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -240,7 +240,6 @@ static int nfs_direct_cmp_commit_data_verf(struct nfs_direct_req *dreq,
 
 /**
  * nfs_direct_IO - NFS address space operation for direct I/O
- * @rw: direction (read or write)
  * @iocb: target I/O control block
  * @iov: array of vectors that define I/O buffer
  * @pos: offset in file to begin the operation
@@ -251,7 +250,7 @@ static int nfs_direct_cmp_commit_data_verf(struct nfs_direct_req *dreq,
  * shunt off direct read and write requests before the VFS gets them,
  * so this method is only ever called for swap.
  */
-ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
+ssize_t nfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
 {
 	struct inode *inode = iocb->ki_filp->f_mapping->host;
 
@@ -267,9 +266,9 @@ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t
 #else
 	VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE);
 
-	if (rw == READ)
+	if (iov_iter_rw(iter) == READ)
 		return nfs_file_direct_read(iocb, iter, pos);
-	return nfs_file_direct_write(iocb, iter, pos);
+	return nfs_file_direct_write(iocb, iter);
 #endif /* CONFIG_NFS_SWAP */
 }
 
@@ -960,8 +959,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
  * Note that O_APPEND is not supported for NFS direct writes, as there
  * is no atomic O_APPEND write facility in the NFS protocol.
  */
-ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
-				loff_t pos)
+ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 {
 	ssize_t result = -EINVAL;
 	struct file *file = iocb->ki_filp;
@@ -969,25 +967,16 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
 	struct inode *inode = mapping->host;
 	struct nfs_direct_req *dreq;
 	struct nfs_lock_context *l_ctx;
-	loff_t end;
-	size_t count = iov_iter_count(iter);
-	end = (pos + count - 1) >> PAGE_CACHE_SHIFT;
-
-	nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count);
+	loff_t pos, end;
 
 	dfprintk(FILE, "NFS: direct write(%pD2, %zd@%Ld)\n",
-		file, count, (long long) pos);
+		file, iov_iter_count(iter), (long long) iocb->ki_pos);
 
-	result = generic_write_checks(file, &pos, &count, 0);
-	if (result)
-		goto out;
+	nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES,
+		      iov_iter_count(iter));
 
-	result = -EINVAL;
-	if ((ssize_t) count < 0)
-		goto out;
-	result = 0;
-	if (!count)
-		goto out;
+	pos = iocb->ki_pos;
+	end = (pos + iov_iter_count(iter) - 1) >> PAGE_CACHE_SHIFT;
 
 	mutex_lock(&inode->i_mutex);
 
@@ -1002,7 +991,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
 			goto out_unlock;
 	}
 
-	task_io_account_write(count);
+	task_io_account_write(iov_iter_count(iter));
 
 	result = -ENOMEM;
 	dreq = nfs_direct_req_alloc();
@@ -1010,7 +999,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter,
 		goto out_unlock;
 
 	dreq->inode = inode;
-	dreq->bytes_left = count;
+	dreq->bytes_left = iov_iter_count(iter);
 	dreq->io_start = pos;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
 	l_ctx = nfs_get_lock_context(dreq->ctx);
@@ -1050,7 +1039,6 @@ out_release:
 	nfs_direct_req_release(dreq);
 out_unlock:
 	mutex_unlock(&inode->i_mutex);
-out:
 	return result;
 }
 
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index f6a3adedf027..c40e4363e746 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -170,7 +170,7 @@ nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
 	struct inode *inode = file_inode(iocb->ki_filp);
 	ssize_t result;
 
-	if (iocb->ki_filp->f_flags & O_DIRECT)
+	if (iocb->ki_flags & IOCB_DIRECT)
 		return nfs_file_direct_read(iocb, to, iocb->ki_pos);
 
 	dprintk("NFS: read(%pD2, %zu@%lu)\n",
@@ -674,17 +674,20 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 	unsigned long written = 0;
 	ssize_t result;
 	size_t count = iov_iter_count(from);
-	loff_t pos = iocb->ki_pos;
 
 	result = nfs_key_timeout_notify(file, inode);
 	if (result)
 		return result;
 
-	if (file->f_flags & O_DIRECT)
-		return nfs_file_direct_write(iocb, from, pos);
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		result = generic_write_checks(iocb, from);
+		if (result <= 0)
+			return result;
+		return nfs_file_direct_write(iocb, from);
+	}
 
 	dprintk("NFS: write(%pD2, %zu@%Ld)\n",
-		file, count, (long long) pos);
+		file, count, (long long) iocb->ki_pos);
 
 	result = -EBUSY;
 	if (IS_SWAPFILE(inode))
@@ -692,7 +695,7 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 	/*
 	 * O_APPEND implies that we must revalidate the file length.
 	 */
-	if (file->f_flags & O_APPEND) {
+	if (iocb->ki_flags & IOCB_APPEND) {
 		result = nfs_revalidate_file_size(inode, file);
 		if (result)
 			goto out;
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 568ecf0a880f..b8f5c63f77b2 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -117,15 +117,15 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
 
 static void nfs_readpage_release(struct nfs_page *req)
 {
-	struct inode *d_inode = req->wb_context->dentry->d_inode;
+	struct inode *inode = req->wb_context->dentry->d_inode;
 
-	dprintk("NFS: read done (%s/%llu %d@%lld)\n", d_inode->i_sb->s_id,
-		(unsigned long long)NFS_FILEID(d_inode), req->wb_bytes,
+	dprintk("NFS: read done (%s/%llu %d@%lld)\n", inode->i_sb->s_id,
+		(unsigned long long)NFS_FILEID(inode), req->wb_bytes,
 		(long long)req_offset(req));
 
 	if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE)) {
 		if (PageUptodate(req->wb_page))
-			nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
+			nfs_readpage_to_fscache(inode, req->wb_page, 0);
 
 		unlock_page(req->wb_page);
 	}
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index ab4987bc637f..36f057fa8aa3 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -305,8 +305,7 @@ static int nilfs_write_end(struct file *file, struct address_space *mapping,
 }
 
 static ssize_t
-nilfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
-		loff_t offset)
+nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
@@ -314,18 +313,17 @@ nilfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 	size_t count = iov_iter_count(iter);
 	ssize_t size;
 
-	if (rw == WRITE)
+	if (iov_iter_rw(iter) == WRITE)
 		return 0;
 
 	/* Needs synchronization with the cleaner */
-	size = blockdev_direct_IO(rw, iocb, inode, iter, offset,
-				  nilfs_get_block);
+	size = blockdev_direct_IO(iocb, inode, iter, offset, nilfs_get_block);
 
 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
-	if (unlikely((rw & WRITE) && size < 0)) {
+	if (unlikely(iov_iter_rw(iter) == WRITE && size < 0)) {
 		loff_t isize = i_size_read(inode);
 		loff_t end = offset + count;
 
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 840e95e3f1d2..7bb487e663b4 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -328,25 +328,25 @@ err_out:
 	return err;
 }
 
-static ssize_t ntfs_prepare_file_for_write(struct file *file, loff_t *ppos,
-		size_t *count)
+static ssize_t ntfs_prepare_file_for_write(struct kiocb *iocb,
+		struct iov_iter *from)
 {
 	loff_t pos;
 	s64 end, ll;
 	ssize_t err;
 	unsigned long flags;
+	struct file *file = iocb->ki_filp;
 	struct inode *vi = file_inode(file);
 	ntfs_inode *base_ni, *ni = NTFS_I(vi);
 	ntfs_volume *vol = ni->vol;
 
 	ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, pos "
-			"0x%llx, count 0x%lx.", vi->i_ino,
+			"0x%llx, count 0x%zx.", vi->i_ino,
 			(unsigned)le32_to_cpu(ni->type),
-			(unsigned long long)*ppos, (unsigned long)*count);
-	/* We can write back this queue in page reclaim. */
-	current->backing_dev_info = inode_to_bdi(vi);
-	err = generic_write_checks(file, ppos, count, S_ISBLK(vi->i_mode));
-	if (unlikely(err))
+			(unsigned long long)iocb->ki_pos,
+			iov_iter_count(from));
+	err = generic_write_checks(iocb, from);
+	if (unlikely(err <= 0))
 		goto out;
 	/*
 	 * All checks have passed.  Before we start doing any writing we want
@@ -379,8 +379,6 @@ static ssize_t ntfs_prepare_file_for_write(struct file *file, loff_t *ppos,
 		err = -EOPNOTSUPP;
 		goto out;
 	}
-	if (*count == 0)
-		goto out;
 	base_ni = ni;
 	if (NInoAttr(ni))
 		base_ni = ni->ext.base_ntfs_ino;
@@ -392,9 +390,9 @@ static ssize_t ntfs_prepare_file_for_write(struct file *file, loff_t *ppos,
 	 * cannot fail either so there is no need to check the return code.
 	 */
 	file_update_time(file);
-	pos = *ppos;
+	pos = iocb->ki_pos;
 	/* The first byte after the last cluster being written to. */
-	end = (pos + *count + vol->cluster_size_mask) &
+	end = (pos + iov_iter_count(from) + vol->cluster_size_mask) &
 			~(u64)vol->cluster_size_mask;
 	/*
 	 * If the write goes beyond the allocated size, extend the allocation
@@ -422,7 +420,7 @@ static ssize_t ntfs_prepare_file_for_write(struct file *file, loff_t *ppos,
 						"partially extended.",
 						vi->i_ino, (unsigned)
 						le32_to_cpu(ni->type));
-				*count = ll - pos;
+				iov_iter_truncate(from, ll - pos);
 			}
 		} else {
 			err = ll;
@@ -438,7 +436,7 @@ static ssize_t ntfs_prepare_file_for_write(struct file *file, loff_t *ppos,
 						vi->i_ino, (unsigned)
 						le32_to_cpu(ni->type),
 						(int)-err);
-				*count = ll - pos;
+				iov_iter_truncate(from, ll - pos);
 			} else {
 				if (err != -ENOSPC)
 					ntfs_error(vi->i_sb, "Cannot perform "
@@ -1930,60 +1928,36 @@ again:
 }
 
 /**
- * ntfs_file_write_iter_nolock - write data to a file
- * @iocb:	IO state structure (file, offset, etc.)
- * @from:	iov_iter with data to write
- *
- * Basically the same as __generic_file_write_iter() except that it ends
- * up calling ntfs_perform_write() instead of generic_perform_write() and that
- * O_DIRECT is not implemented.
- */
-static ssize_t ntfs_file_write_iter_nolock(struct kiocb *iocb,
-		struct iov_iter *from)
-{
-	struct file *file = iocb->ki_filp;
-	loff_t pos = iocb->ki_pos;
-	ssize_t written = 0;
-	ssize_t err;
-	size_t count = iov_iter_count(from);
-
-	err = ntfs_prepare_file_for_write(file, &pos, &count);
-	if (count && !err) {
-		iov_iter_truncate(from, count);
-		written = ntfs_perform_write(file, from, pos);
-		if (likely(written >= 0))
-			iocb->ki_pos = pos + written;
-	}
-	current->backing_dev_info = NULL;
-	return written ? written : err;
-}
-
-/**
  * ntfs_file_write_iter - simple wrapper for ntfs_file_write_iter_nolock()
  * @iocb:	IO state structure
  * @from:	iov_iter with data to write
  *
  * Basically the same as generic_file_write_iter() except that it ends up
- * calling ntfs_file_write_iter_nolock() instead of
- * __generic_file_write_iter().
+ * up calling ntfs_perform_write() instead of generic_perform_write() and that
+ * O_DIRECT is not implemented.
  */
 static ssize_t ntfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *vi = file_inode(file);
-	ssize_t ret;
+	ssize_t written = 0;
+	ssize_t err;
 
 	mutex_lock(&vi->i_mutex);
-	ret = ntfs_file_write_iter_nolock(iocb, from);
+	/* We can write back this queue in page reclaim. */
+	current->backing_dev_info = inode_to_bdi(vi);
+	err = ntfs_prepare_file_for_write(iocb, from);
+	if (iov_iter_count(from) && !err)
+		written = ntfs_perform_write(file, from, iocb->ki_pos);
+	current->backing_dev_info = NULL;
 	mutex_unlock(&vi->i_mutex);
-	if (ret > 0) {
-		ssize_t err;
-
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
+	if (likely(written > 0)) {
+		err = generic_write_sync(file, iocb->ki_pos, written);
 		if (err < 0)
-			ret = err;
+			written = 0;
 	}
-	return ret;
+	iocb->ki_pos += written;
+	return written ? written : err;
 }
 
 /**
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 8d2bc840c288..f906a250da6a 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -855,10 +855,9 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb,
 		ocfs2_inode_unlock(inode, 1);
 	}
 
-	written = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
-			iter, offset,
-			ocfs2_direct_IO_get_blocks,
-			ocfs2_dio_end_io, NULL, 0);
+	written = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
+				       offset, ocfs2_direct_IO_get_blocks,
+				       ocfs2_dio_end_io, NULL, 0);
 	if (unlikely(written < 0)) {
 		loff_t i_size = i_size_read(inode);
 
@@ -946,9 +945,7 @@ out:
 	return ret;
 }
 
-static ssize_t ocfs2_direct_IO(int rw,
-			       struct kiocb *iocb,
-			       struct iov_iter *iter,
+static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 			       loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
@@ -970,12 +967,11 @@ static ssize_t ocfs2_direct_IO(int rw,
 	if (i_size_read(inode) <= offset && !full_coherency)
 		return 0;
 
-	if (rw == READ)
-		return __blockdev_direct_IO(rw, iocb, inode,
-				    inode->i_sb->s_bdev,
-				    iter, offset,
-				    ocfs2_direct_IO_get_blocks,
-				    ocfs2_dio_end_io, NULL, 0);
+	if (iov_iter_rw(iter) == READ)
+		return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
+					    iter, offset,
+					    ocfs2_direct_IO_get_blocks,
+					    ocfs2_dio_end_io, NULL, 0);
 	else
 		return ocfs2_direct_IO_write(iocb, iter, offset);
 }
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 8c48e989beba..913fc250d85a 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2106,7 +2106,7 @@ out:
 }
 
 static int ocfs2_prepare_inode_for_write(struct file *file,
-					 loff_t *ppos,
+					 loff_t pos,
 					 size_t count,
 					 int appending,
 					 int *direct_io,
@@ -2115,7 +2115,7 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 	int ret = 0, meta_level = 0;
 	struct dentry *dentry = file->f_path.dentry;
 	struct inode *inode = dentry->d_inode;
-	loff_t saved_pos = 0, end;
+	loff_t end;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	int full_coherency = !(osb->s_mount_opt &
 		OCFS2_MOUNT_COHERENCY_BUFFERED);
@@ -2155,23 +2155,16 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 			}
 		}
 
-		/* work on a copy of ppos until we're sure that we won't have
-		 * to recalculate it due to relocking. */
-		if (appending)
-			saved_pos = i_size_read(inode);
-		else
-			saved_pos = *ppos;
-
-		end = saved_pos + count;
+		end = pos + count;
 
-		ret = ocfs2_check_range_for_refcount(inode, saved_pos, count);
+		ret = ocfs2_check_range_for_refcount(inode, pos, count);
 		if (ret == 1) {
 			ocfs2_inode_unlock(inode, meta_level);
 			meta_level = -1;
 
 			ret = ocfs2_prepare_inode_for_refcount(inode,
 							       file,
-							       saved_pos,
+							       pos,
 							       count,
 							       &meta_level);
 			if (has_refcount)
@@ -2227,7 +2220,7 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 		 * caller will have to retake some cluster
 		 * locks and initiate the io as buffered.
 		 */
-		ret = ocfs2_check_range_for_holes(inode, saved_pos, count);
+		ret = ocfs2_check_range_for_holes(inode, pos, count);
 		if (ret == 1) {
 			/*
 			 * Fallback to old way if the feature bit is not set.
@@ -2242,12 +2235,9 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 		break;
 	}
 
-	if (appending)
-		*ppos = saved_pos;
-
 out_unlock:
 	trace_ocfs2_prepare_inode_for_write(OCFS2_I(inode)->ip_blkno,
-					    saved_pos, appending, count,
+					    pos, appending, count,
 					    direct_io, has_refcount);
 
 	if (meta_level >= 0)
@@ -2260,19 +2250,20 @@ out:
 static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
 				    struct iov_iter *from)
 {
-	int ret, direct_io, appending, rw_level, have_alloc_sem  = 0;
+	int direct_io, appending, rw_level, have_alloc_sem  = 0;
 	int can_do_direct, has_refcount = 0;
 	ssize_t written = 0;
-	size_t count = iov_iter_count(from);
-	loff_t old_size, *ppos = &iocb->ki_pos;
+	ssize_t ret;
+	size_t count = iov_iter_count(from), orig_count;
+	loff_t old_size;
 	u32 old_clusters;
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
-	struct address_space *mapping = file->f_mapping;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	int full_coherency = !(osb->s_mount_opt &
 			       OCFS2_MOUNT_COHERENCY_BUFFERED);
 	int unaligned_dio = 0;
+	int dropped_dio = 0;
 
 	trace_ocfs2_file_aio_write(inode, file, file->f_path.dentry,
 		(unsigned long long)OCFS2_I(inode)->ip_blkno,
@@ -2283,8 +2274,8 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
 	if (count == 0)
 		return 0;
 
-	appending = file->f_flags & O_APPEND ? 1 : 0;
-	direct_io = file->f_flags & O_DIRECT ? 1 : 0;
+	appending = iocb->ki_flags & IOCB_APPEND ? 1 : 0;
+	direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0;
 
 	mutex_lock(&inode->i_mutex);
 
@@ -2329,8 +2320,17 @@ relock:
 		ocfs2_inode_unlock(inode, 1);
 	}
 
+	orig_count = iov_iter_count(from);
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0) {
+		if (ret)
+			mlog_errno(ret);
+		goto out;
+	}
+	count = ret;
+
 	can_do_direct = direct_io;
-	ret = ocfs2_prepare_inode_for_write(file, ppos, count, appending,
+	ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count, appending,
 					    &can_do_direct, &has_refcount);
 	if (ret < 0) {
 		mlog_errno(ret);
@@ -2338,7 +2338,7 @@ relock:
 	}
 
 	if (direct_io && !is_sync_kiocb(iocb))
-		unaligned_dio = ocfs2_is_io_unaligned(inode, count, *ppos);
+		unaligned_dio = ocfs2_is_io_unaligned(inode, count, iocb->ki_pos);
 
 	/*
 	 * We can't complete the direct I/O as requested, fall back to
@@ -2351,6 +2351,9 @@ relock:
 		rw_level = -1;
 
 		direct_io = 0;
+		iocb->ki_flags &= ~IOCB_DIRECT;
+		iov_iter_reexpand(from, orig_count);
+		dropped_dio = 1;
 		goto relock;
 	}
 
@@ -2374,74 +2377,15 @@ relock:
 	/* communicate with ocfs2_dio_end_io */
 	ocfs2_iocb_set_rw_locked(iocb, rw_level);
 
-	ret = generic_write_checks(file, ppos, &count,
-				   S_ISBLK(inode->i_mode));
-	if (ret)
-		goto out_dio;
-
-	iov_iter_truncate(from, count);
-	if (direct_io) {
-		loff_t endbyte;
-		ssize_t written_buffered;
-		written = generic_file_direct_write(iocb, from, *ppos);
-		if (written < 0 || written == count) {
-			ret = written;
-			goto out_dio;
-		}
-
-		/*
-		 * for completing the rest of the request.
-		 */
-		count -= written;
-		written_buffered = generic_perform_write(file, from, *ppos);
-		/*
-		 * If generic_file_buffered_write() returned a synchronous error
-		 * then we want to return the number of bytes which were
-		 * direct-written, or the error code if that was zero. Note
-		 * that this differs from normal direct-io semantics, which
-		 * will return -EFOO even if some bytes were written.
-		 */
-		if (written_buffered < 0) {
-			ret = written_buffered;
-			goto out_dio;
-		}
-
-		/* We need to ensure that the page cache pages are written to
-		 * disk and invalidated to preserve the expected O_DIRECT
-		 * semantics.
-		 */
-		endbyte = *ppos + written_buffered - 1;
-		ret = filemap_write_and_wait_range(file->f_mapping, *ppos,
-				endbyte);
-		if (ret == 0) {
-			iocb->ki_pos = *ppos + written_buffered;
-			written += written_buffered;
-			invalidate_mapping_pages(mapping,
-					*ppos >> PAGE_CACHE_SHIFT,
-					endbyte >> PAGE_CACHE_SHIFT);
-		} else {
-			/*
-			 * We don't know how much we wrote, so just return
-			 * the number of bytes which were direct-written
-			 */
-		}
-	} else {
-		current->backing_dev_info = inode_to_bdi(inode);
-		written = generic_perform_write(file, from, *ppos);
-		if (likely(written >= 0))
-			iocb->ki_pos = *ppos + written;
-		current->backing_dev_info = NULL;
-	}
-
-out_dio:
+	written = __generic_file_write_iter(iocb, from);
 	/* buffered aio wouldn't have proper lock coverage today */
-	BUG_ON(ret == -EIOCBQUEUED && !(file->f_flags & O_DIRECT));
+	BUG_ON(written == -EIOCBQUEUED && !(iocb->ki_flags & IOCB_DIRECT));
 
 	if (unlikely(written <= 0))
 		goto no_sync;
 
-	if (((file->f_flags & O_DSYNC) && !direct_io) || IS_SYNC(inode) ||
-	    ((file->f_flags & O_DIRECT) && !direct_io)) {
+	if (((file->f_flags & O_DSYNC) && !direct_io) ||
+	    IS_SYNC(inode) || dropped_dio) {
 		ret = filemap_fdatawrite_range(file->f_mapping,
 					       iocb->ki_pos - written,
 					       iocb->ki_pos - 1);
@@ -2552,7 +2496,7 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb,
 	 * buffered reads protect themselves in ->readpage().  O_DIRECT reads
 	 * need locks to protect pending reads from racing with truncate.
 	 */
-	if (filp->f_flags & O_DIRECT) {
+	if (iocb->ki_flags & IOCB_DIRECT) {
 		have_alloc_sem = 1;
 		ocfs2_iocb_set_sem_locked(iocb);
 
@@ -2586,7 +2530,7 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb,
 	trace_generic_file_aio_read_ret(ret);
 
 	/* buffered aio wouldn't have proper lock coverage today */
-	BUG_ON(ret == -EIOCBQUEUED && !(filp->f_flags & O_DIRECT));
+	BUG_ON(ret == -EIOCBQUEUED && !(iocb->ki_flags & IOCB_DIRECT));
 
 	/* see ocfs2_file_write_iter */
 	if (ret == -EIOCBQUEUED || !ocfs2_iocb_is_rw_locked(iocb)) {
diff --git a/fs/read_write.c b/fs/read_write.c
index 45d583c33879..819ef3faf1bb 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -477,7 +477,8 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
 
 	ret = filp->f_op->write_iter(&kiocb, &iter);
 	BUG_ON(ret == -EIOCBQUEUED);
-	*ppos = kiocb.ki_pos;
+	if (ret > 0)
+		*ppos = kiocb.ki_pos;
 	return ret;
 }
 
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 9312b7842e03..742242b60972 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -3278,22 +3278,22 @@ static int reiserfs_releasepage(struct page *page, gfp_t unused_gfp_flags)
  * We thank Mingming Cao for helping us understand in great detail what
  * to do in this section of the code.
  */
-static ssize_t reiserfs_direct_IO(int rw, struct kiocb *iocb,
-				  struct iov_iter *iter, loff_t offset)
+static ssize_t reiserfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+				  loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset,
+	ret = blockdev_direct_IO(iocb, inode, iter, offset,
 				 reiserfs_get_blocks_direct_io);
 
 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
-	if (unlikely((rw & WRITE) && ret < 0)) {
+	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
 		loff_t end = offset + count;
 
diff --git a/fs/udf/file.c b/fs/udf/file.c
index f77f7681288f..5dadad9960b9 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -99,8 +99,7 @@ static int udf_adinicb_write_begin(struct file *file,
 	return 0;
 }
 
-static ssize_t udf_adinicb_direct_IO(int rw, struct kiocb *iocb,
-				     struct iov_iter *iter,
+static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 				     loff_t offset)
 {
 	/* Fallback to buffered I/O. */
@@ -120,21 +119,21 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	ssize_t retval;
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
-	int err, pos;
-	size_t count = iov_iter_count(from);
 	struct udf_inode_info *iinfo = UDF_I(inode);
+	int err;
 
 	mutex_lock(&inode->i_mutex);
+
+	retval = generic_write_checks(iocb, from);
+	if (retval <= 0)
+		goto out;
+
 	down_write(&iinfo->i_data_sem);
 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
-		if (file->f_flags & O_APPEND)
-			pos = inode->i_size;
-		else
-			pos = iocb->ki_pos;
+		loff_t end = iocb->ki_pos + iov_iter_count(from);
 
 		if (inode->i_sb->s_blocksize <
-				(udf_file_entry_alloc_offset(inode) +
-						pos + count)) {
+				(udf_file_entry_alloc_offset(inode) + end)) {
 			err = udf_expand_file_adinicb(inode);
 			if (err) {
 				mutex_unlock(&inode->i_mutex);
@@ -142,16 +141,14 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 				return err;
 			}
 		} else {
-			if (pos + count > inode->i_size)
-				iinfo->i_lenAlloc = pos + count;
-			else
-				iinfo->i_lenAlloc = inode->i_size;
+			iinfo->i_lenAlloc = max(end, inode->i_size);
 			up_write(&iinfo->i_data_sem);
 		}
 	} else
 		up_write(&iinfo->i_data_sem);
 
 	retval = __generic_file_write_iter(iocb, from);
+out:
 	mutex_unlock(&inode->i_mutex);
 
 	if (retval > 0) {
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 9e3d780e5eff..6afac3d561ac 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -214,8 +214,7 @@ static int udf_write_begin(struct file *file, struct address_space *mapping,
 	return ret;
 }
 
-static ssize_t udf_direct_IO(int rw, struct kiocb *iocb,
-			     struct iov_iter *iter,
+static ssize_t udf_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 			     loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
@@ -224,8 +223,8 @@ static ssize_t udf_direct_IO(int rw, struct kiocb *iocb,
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;
 
-	ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, udf_get_block);
-	if (unlikely(ret < 0 && (rw & WRITE)))
+	ret = blockdev_direct_IO(iocb, inode, iter, offset, udf_get_block);
+	if (unlikely(ret < 0 && iov_iter_rw(iter) == WRITE))
 		udf_write_failed(mapping, offset + count);
 	return ret;
 }
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 4f8cdc59bc38..1d8eef9cf0f5 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1495,7 +1495,6 @@ xfs_end_io_direct_write(
 
 STATIC ssize_t
 xfs_vm_direct_IO(
-	int			rw,
 	struct kiocb		*iocb,
 	struct iov_iter		*iter,
 	loff_t			offset)
@@ -1503,15 +1502,14 @@ xfs_vm_direct_IO(
 	struct inode		*inode = iocb->ki_filp->f_mapping->host;
 	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
 
-	if (rw & WRITE) {
-		return __blockdev_direct_IO(rw, iocb, inode, bdev, iter,
-					    offset, xfs_get_blocks_direct,
+	if (iov_iter_rw(iter) == WRITE) {
+		return __blockdev_direct_IO(iocb, inode, bdev, iter, offset,
+					    xfs_get_blocks_direct,
 					    xfs_end_io_direct_write, NULL,
 					    DIO_ASYNC_EXTEND);
 	}
-	return __blockdev_direct_IO(rw, iocb, inode, bdev, iter,
-				    offset, xfs_get_blocks_direct,
-				    NULL, NULL, 0);
+	return __blockdev_direct_IO(iocb, inode, bdev, iter, offset,
+				    xfs_get_blocks_direct, NULL, NULL, 0);
 }
 
 /*
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 44856c3b9617..1f12ad0a8585 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -279,7 +279,7 @@ xfs_file_read_iter(
 
 	XFS_STATS_INC(xs_read_calls);
 
-	if (unlikely(file->f_flags & O_DIRECT))
+	if (unlikely(iocb->ki_flags & IOCB_DIRECT))
 		ioflags |= XFS_IO_ISDIRECT;
 	if (file->f_mode & FMODE_NOCMTIME)
 		ioflags |= XFS_IO_INVIS;
@@ -544,18 +544,19 @@ xfs_zero_eof(
  */
 STATIC ssize_t
 xfs_file_aio_write_checks(
-	struct file		*file,
-	loff_t			*pos,
-	size_t			*count,
+	struct kiocb		*iocb,
+	struct iov_iter		*from,
 	int			*iolock)
 {
+	struct file		*file = iocb->ki_filp;
 	struct inode		*inode = file->f_mapping->host;
 	struct xfs_inode	*ip = XFS_I(inode);
-	int			error = 0;
+	ssize_t			error = 0;
+	size_t			count = iov_iter_count(from);
 
 restart:
-	error = generic_write_checks(file, pos, count, S_ISBLK(inode->i_mode));
-	if (error)
+	error = generic_write_checks(iocb, from);
+	if (error <= 0)
 		return error;
 
 	error = xfs_break_layouts(inode, iolock);
@@ -569,16 +570,17 @@ restart:
 	 * iolock shared, we need to update it to exclusive which implies
 	 * having to redo all checks before.
 	 */
-	if (*pos > i_size_read(inode)) {
+	if (iocb->ki_pos > i_size_read(inode)) {
 		bool	zero = false;
 
 		if (*iolock == XFS_IOLOCK_SHARED) {
 			xfs_rw_iunlock(ip, *iolock);
 			*iolock = XFS_IOLOCK_EXCL;
 			xfs_rw_ilock(ip, *iolock);
+			iov_iter_reexpand(from, count);
 			goto restart;
 		}
-		error = xfs_zero_eof(ip, *pos, i_size_read(inode), &zero);
+		error = xfs_zero_eof(ip, iocb->ki_pos, i_size_read(inode), &zero);
 		if (error)
 			return error;
 	}
@@ -678,10 +680,11 @@ xfs_file_dio_aio_write(
 		xfs_rw_ilock(ip, iolock);
 	}
 
-	ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
+	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
 	if (ret)
 		goto out;
-	iov_iter_truncate(from, count);
+	count = iov_iter_count(from);
+	pos = iocb->ki_pos;
 
 	if (mapping->nrpages) {
 		ret = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
@@ -734,24 +737,22 @@ xfs_file_buffered_aio_write(
 	ssize_t			ret;
 	int			enospc = 0;
 	int			iolock = XFS_IOLOCK_EXCL;
-	loff_t			pos = iocb->ki_pos;
-	size_t			count = iov_iter_count(from);
 
 	xfs_rw_ilock(ip, iolock);
 
-	ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
+	ret = xfs_file_aio_write_checks(iocb, from, &iolock);
 	if (ret)
 		goto out;
 
-	iov_iter_truncate(from, count);
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
 
 write_retry:
-	trace_xfs_file_buffered_write(ip, count, iocb->ki_pos, 0);
-	ret = generic_perform_write(file, from, pos);
+	trace_xfs_file_buffered_write(ip, iov_iter_count(from),
+				      iocb->ki_pos, 0);
+	ret = generic_perform_write(file, from, iocb->ki_pos);
 	if (likely(ret >= 0))
-		iocb->ki_pos = pos + ret;
+		iocb->ki_pos += ret;
 
 	/*
 	 * If we hit a space limit, try to free up some lingering preallocated
@@ -803,7 +804,7 @@ xfs_file_write_iter(
 	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 		return -EIO;
 
-	if (unlikely(file->f_flags & O_DIRECT))
+	if (unlikely(iocb->ki_flags & IOCB_DIRECT))
 		ret = xfs_file_dio_aio_write(iocb, from);
 	else
 		ret = xfs_file_buffered_aio_write(iocb, from);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index d8358799c594..df334cbacc6d 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -404,26 +404,11 @@ static inline bool d_mountpoint(const struct dentry *dentry)
 /*
  * Directory cache entry type accessor functions.
  */
-static inline void __d_set_type(struct dentry *dentry, unsigned type)
-{
-	dentry->d_flags = (dentry->d_flags & ~DCACHE_ENTRY_TYPE) | type;
-}
-
-static inline void __d_clear_type(struct dentry *dentry)
-{
-	__d_set_type(dentry, DCACHE_MISS_TYPE);
-}
-
-static inline void d_set_type(struct dentry *dentry, unsigned type)
-{
-	spin_lock(&dentry->d_lock);
-	__d_set_type(dentry, type);
-	spin_unlock(&dentry->d_lock);
-}
-
 static inline unsigned __d_entry_type(const struct dentry *dentry)
 {
-	return dentry->d_flags & DCACHE_ENTRY_TYPE;
+	unsigned type = READ_ONCE(dentry->d_flags);
+	smp_rmb();
+	return type & DCACHE_ENTRY_TYPE;
 }
 
 static inline bool d_is_miss(const struct dentry *dentry)
@@ -482,6 +467,44 @@ static inline bool d_is_positive(const struct dentry *dentry)
 	return !d_is_negative(dentry);
 }
 
+/**
+ * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs)
+ * @dentry: The dentry in question
+ *
+ * Returns true if the dentry represents either an absent name or a name that
+ * doesn't map to an inode (ie. ->d_inode is NULL).  The dentry could represent
+ * a true miss, a whiteout that isn't represented by a 0,0 chardev or a
+ * fallthrough marker in an opaque directory.
+ *
+ * Note!  (1) This should be used *only* by a filesystem to examine its own
+ * dentries.  It should not be used to look at some other filesystem's
+ * dentries.  (2) It should also be used in combination with d_inode() to get
+ * the inode.  (3) The dentry may have something attached to ->d_lower and the
+ * type field of the flags may be set to something other than miss or whiteout.
+ */
+static inline bool d_really_is_negative(const struct dentry *dentry)
+{
+	return dentry->d_inode == NULL;
+}
+
+/**
+ * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs)
+ * @dentry: The dentry in question
+ *
+ * Returns true if the dentry represents a name that maps to an inode
+ * (ie. ->d_inode is not NULL).  The dentry might still represent a whiteout if
+ * that is represented on medium as a 0,0 chardev.
+ *
+ * Note!  (1) This should be used *only* by a filesystem to examine its own
+ * dentries.  It should not be used to look at some other filesystem's
+ * dentries.  (2) It should also be used in combination with d_inode() to get
+ * the inode.
+ */
+static inline bool d_really_is_positive(const struct dentry *dentry)
+{
+	return dentry->d_inode != NULL;
+}
+
 extern void d_set_fallthru(struct dentry *dentry);
 
 static inline bool d_is_fallthru(const struct dentry *dentry)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f4fc60727b8d..f4d63544a791 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -315,6 +315,8 @@ struct address_space;
 struct writeback_control;
 
 #define IOCB_EVENTFD		(1 << 0)
+#define IOCB_APPEND		(1 << 1)
+#define IOCB_DIRECT		(1 << 2)
 
 struct kiocb {
 	struct file		*ki_filp;
@@ -329,10 +331,13 @@ static inline bool is_sync_kiocb(struct kiocb *kiocb)
 	return kiocb->ki_complete == NULL;
 }
 
+static inline int iocb_flags(struct file *file);
+
 static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
 {
 	*kiocb = (struct kiocb) {
 		.ki_filp = filp,
+		.ki_flags = iocb_flags(filp),
 	};
 }
 
@@ -383,7 +388,7 @@ struct address_space_operations {
 	void (*invalidatepage) (struct page *, unsigned int, unsigned int);
 	int (*releasepage) (struct page *, gfp_t);
 	void (*freepage)(struct page *);
-	ssize_t (*direct_IO)(int, struct kiocb *, struct iov_iter *iter, loff_t offset);
+	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter, loff_t offset);
 	/*
 	 * migrate the contents of a page to the specified target. If
 	 * migrate_mode is MIGRATE_ASYNC, it must not block.
@@ -2566,7 +2571,7 @@ extern int sb_min_blocksize(struct super_block *, int);
 
 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
-int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);
+extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
@@ -2609,8 +2614,8 @@ extern loff_t fixed_size_llseek(struct file *file, loff_t offset,
 extern int generic_file_open(struct inode * inode, struct file * filp);
 extern int nonseekable_open(struct inode * inode, struct file * filp);
 
-ssize_t dax_do_io(int rw, struct kiocb *, struct inode *, struct iov_iter *,
-		loff_t, get_block_t, dio_iodone_t, int flags);
+ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
+		  get_block_t, dio_iodone_t, int flags);
 int dax_clear_blocks(struct inode *, sector_t block, long size);
 int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
 int dax_truncate_page(struct inode *, loff_t from, get_block_t);
@@ -2635,16 +2640,18 @@ enum {
 
 void dio_end_io(struct bio *bio, int error);
 
-ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
-	struct block_device *bdev, struct iov_iter *iter, loff_t offset,
-	get_block_t get_block, dio_iodone_t end_io,
-	dio_submit_t submit_io,	int flags);
+ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
+			     struct block_device *bdev, struct iov_iter *iter,
+			     loff_t offset, get_block_t get_block,
+			     dio_iodone_t end_io, dio_submit_t submit_io,
+			     int flags);
 
-static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
-		struct inode *inode, struct iov_iter *iter, loff_t offset,
-		get_block_t get_block)
+static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
+					 struct inode *inode,
+					 struct iov_iter *iter, loff_t offset,
+					 get_block_t get_block)
 {
-	return __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iter,
+	return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
 				    offset, get_block, NULL, NULL,
 				    DIO_LOCKING | DIO_SKIP_HOLES);
 }
@@ -2777,6 +2784,16 @@ static inline bool io_is_direct(struct file *filp)
 	return (filp->f_flags & O_DIRECT) || IS_DAX(file_inode(filp));
 }
 
+static inline int iocb_flags(struct file *file)
+{
+	int res = 0;
+	if (file->f_flags & O_APPEND)
+		res |= IOCB_APPEND;
+	if (io_is_direct(file))
+		res |= IOCB_DIRECT;
+	return res;
+}
+
 static inline ino_t parent_ino(struct dentry *dentry)
 {
 	ino_t res;
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index b01ccf371fdc..410abd172feb 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -447,13 +447,12 @@ static inline struct rpc_cred *nfs_file_cred(struct file *file)
 /*
  * linux/fs/nfs/direct.c
  */
-extern ssize_t nfs_direct_IO(int, struct kiocb *, struct iov_iter *, loff_t);
+extern ssize_t nfs_direct_IO(struct kiocb *, struct iov_iter *, loff_t);
 extern ssize_t nfs_file_direct_read(struct kiocb *iocb,
 			struct iov_iter *iter,
 			loff_t pos);
 extern ssize_t nfs_file_direct_write(struct kiocb *iocb,
-			struct iov_iter *iter,
-			loff_t pos);
+			struct iov_iter *iter);
 
 /*
  * linux/fs/nfs/dir.c
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 15f11fb9fff6..8b01e1c3c614 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -112,6 +112,14 @@ static inline bool iter_is_iovec(struct iov_iter *i)
 }
 
 /*
+ * Get one of READ or WRITE out of iter->type without any other flags OR'd in
+ * with it.
+ *
+ * The ?: is just for type safety.
+ */
+#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & RW_MASK)
+
+/*
  * Cap the iov_iter by given limit; note that the second argument is
  * *not* the new size - it's upper limit for such.  Passing it a value
  * greater than the amount of data in iov_iter is fine - it'll just do
diff --git a/mm/filemap.c b/mm/filemap.c
index 12548d03c11d..6bf5e42d560a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1693,7 +1693,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 	loff_t *ppos = &iocb->ki_pos;
 	loff_t pos = *ppos;
 
-	if (io_is_direct(file)) {
+	if (iocb->ki_flags & IOCB_DIRECT) {
 		struct address_space *mapping = file->f_mapping;
 		struct inode *inode = mapping->host;
 		size_t count = iov_iter_count(iter);
@@ -1706,7 +1706,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 					pos + count - 1);
 		if (!retval) {
 			struct iov_iter data = *iter;
-			retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos);
+			retval = mapping->a_ops->direct_IO(iocb, &data, pos);
 		}
 
 		if (retval > 0) {
@@ -2259,41 +2259,38 @@ EXPORT_SYMBOL(read_cache_page_gfp);
  * Returns appropriate error code that caller should return or
  * zero in case that write should be allowed.
  */
-inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk)
+inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
 {
+	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	unsigned long limit = rlimit(RLIMIT_FSIZE);
+	loff_t pos;
 
-        if (unlikely(*pos < 0))
-                return -EINVAL;
+	if (!iov_iter_count(from))
+		return 0;
 
-	if (!isblk) {
-		/* FIXME: this is for backwards compatibility with 2.4 */
-		if (file->f_flags & O_APPEND)
-                        *pos = i_size_read(inode);
+	/* FIXME: this is for backwards compatibility with 2.4 */
+	if (iocb->ki_flags & IOCB_APPEND)
+		iocb->ki_pos = i_size_read(inode);
 
-		if (limit != RLIM_INFINITY) {
-			if (*pos >= limit) {
-				send_sig(SIGXFSZ, current, 0);
-				return -EFBIG;
-			}
-			if (*count > limit - (typeof(limit))*pos) {
-				*count = limit - (typeof(limit))*pos;
-			}
+	pos = iocb->ki_pos;
+
+	if (limit != RLIM_INFINITY) {
+		if (iocb->ki_pos >= limit) {
+			send_sig(SIGXFSZ, current, 0);
+			return -EFBIG;
 		}
+		iov_iter_truncate(from, limit - (unsigned long)pos);
 	}
 
 	/*
 	 * LFS rule
 	 */
-	if (unlikely(*pos + *count > MAX_NON_LFS &&
+	if (unlikely(pos + iov_iter_count(from) > MAX_NON_LFS &&
 				!(file->f_flags & O_LARGEFILE))) {
-		if (*pos >= MAX_NON_LFS) {
+		if (pos >= MAX_NON_LFS)
 			return -EFBIG;
-		}
-		if (*count > MAX_NON_LFS - (unsigned long)*pos) {
-			*count = MAX_NON_LFS - (unsigned long)*pos;
-		}
+		iov_iter_truncate(from, MAX_NON_LFS - (unsigned long)pos);
 	}
 
 	/*
@@ -2303,34 +2300,11 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i
 	 * exceeded without writing data we send a signal and return EFBIG.
 	 * Linus frestrict idea will clean these up nicely..
 	 */
-	if (likely(!isblk)) {
-		if (unlikely(*pos >= inode->i_sb->s_maxbytes)) {
-			if (*count || *pos > inode->i_sb->s_maxbytes) {
-				return -EFBIG;
-			}
-			/* zero-length writes at ->s_maxbytes are OK */
-		}
+	if (unlikely(pos >= inode->i_sb->s_maxbytes))
+		return -EFBIG;
 
-		if (unlikely(*pos + *count > inode->i_sb->s_maxbytes))
-			*count = inode->i_sb->s_maxbytes - *pos;
-	} else {
-#ifdef CONFIG_BLOCK
-		loff_t isize;
-		if (bdev_read_only(I_BDEV(inode)))
-			return -EPERM;
-		isize = i_size_read(inode);
-		if (*pos >= isize) {
-			if (*count || *pos > isize)
-				return -ENOSPC;
-		}
-
-		if (*pos + *count > isize)
-			*count = isize - *pos;
-#else
-		return -EPERM;
-#endif
-	}
-	return 0;
+	iov_iter_truncate(from, inode->i_sb->s_maxbytes - pos);
+	return iov_iter_count(from);
 }
 EXPORT_SYMBOL(generic_write_checks);
 
@@ -2394,7 +2368,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 	}
 
 	data = *from;
-	written = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos);
+	written = mapping->a_ops->direct_IO(iocb, &data, pos);
 
 	/*
 	 * Finally, try again to invalidate clean pages which might have been
@@ -2556,23 +2530,12 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct file *file = iocb->ki_filp;
 	struct address_space * mapping = file->f_mapping;
 	struct inode 	*inode = mapping->host;
-	loff_t		pos = iocb->ki_pos;
 	ssize_t		written = 0;
 	ssize_t		err;
 	ssize_t		status;
-	size_t		count = iov_iter_count(from);
 
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
-	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
-	if (err)
-		goto out;
-
-	if (count == 0)
-		goto out;
-
-	iov_iter_truncate(from, count);
-
 	err = file_remove_suid(file);
 	if (err)
 		goto out;
@@ -2581,10 +2544,10 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (err)
 		goto out;
 
-	if (io_is_direct(file)) {
-		loff_t endbyte;
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		loff_t pos, endbyte;
 
-		written = generic_file_direct_write(iocb, from, pos);
+		written = generic_file_direct_write(iocb, from, iocb->ki_pos);
 		/*
 		 * If the write stopped short of completing, fall back to
 		 * buffered writes.  Some filesystems do this for writes to
@@ -2592,13 +2555,10 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		 * not succeed (even if it did, DAX does not handle dirty
 		 * page-cache pages correctly).
 		 */
-		if (written < 0 || written == count || IS_DAX(inode))
+		if (written < 0 || !iov_iter_count(from) || IS_DAX(inode))
 			goto out;
 
-		pos += written;
-		count -= written;
-
-		status = generic_perform_write(file, from, pos);
+		status = generic_perform_write(file, from, pos = iocb->ki_pos);
 		/*
 		 * If generic_perform_write() returned a synchronous error
 		 * then we want to return the number of bytes which were
@@ -2610,15 +2570,15 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			err = status;
 			goto out;
 		}
-		iocb->ki_pos = pos + status;
 		/*
 		 * We need to ensure that the page cache pages are written to
 		 * disk and invalidated to preserve the expected O_DIRECT
 		 * semantics.
 		 */
 		endbyte = pos + status - 1;
-		err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
+		err = filemap_write_and_wait_range(mapping, pos, endbyte);
 		if (err == 0) {
+			iocb->ki_pos = endbyte + 1;
 			written += status;
 			invalidate_mapping_pages(mapping,
 						 pos >> PAGE_CACHE_SHIFT,
@@ -2630,9 +2590,9 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			 */
 		}
 	} else {
-		written = generic_perform_write(file, from, pos);
-		if (likely(written >= 0))
-			iocb->ki_pos = pos + written;
+		written = generic_perform_write(file, from, iocb->ki_pos);
+		if (likely(written > 0))
+			iocb->ki_pos += written;
 	}
 out:
 	current->backing_dev_info = NULL;
@@ -2656,7 +2616,9 @@ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	ssize_t ret;
 
 	mutex_lock(&inode->i_mutex);
-	ret = __generic_file_write_iter(iocb, from);
+	ret = generic_write_checks(iocb, from);
+	if (ret > 0)
+		ret = __generic_file_write_iter(iocb, from);
 	mutex_unlock(&inode->i_mutex);
 
 	if (ret > 0) {
diff --git a/mm/page_io.c b/mm/page_io.c
index a96c8562d835..6424869e275e 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -277,9 +277,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
 
 		set_page_writeback(page);
 		unlock_page(page);
-		ret = mapping->a_ops->direct_IO(ITER_BVEC | WRITE,
-						&kiocb, &from,
-						kiocb.ki_pos);
+		ret = mapping->a_ops->direct_IO(&kiocb, &from, kiocb.ki_pos);
 		if (ret == PAGE_SIZE) {
 			count_vm_event(PSWPOUT);
 			ret = 0;