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

Pull fuse updates from Miklos Szeredi:
 "This contains two patchsets from Maxim Patlasov.

  The first reworks the request throttling so that only async requests
  are throttled.  Wakeup of waiting async requests is also optimized.

  The second series adds support for async processing of direct IO which
  optimizes direct IO and enables the use of the AIO userspace
  interface."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: add flag to turn on async direct IO
  fuse: truncate file if async dio failed
  fuse: optimize short direct reads
  fuse: enable asynchronous processing direct IO
  fuse: make fuse_direct_io() aware about AIO
  fuse: add support of async IO
  fuse: move fuse_release_user_pages() up
  fuse: optimize wake_up
  fuse: implement exclusive wakeup for blocked_waitq
  fuse: skip blocking on allocations of synchronous requests
  fuse: add flag fc->initialized
  fuse: make request allocations for background processing explicit

1 files changed, 234 insertions, 38 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index d15c6f2..4655e59 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -126,11 +126,13 @@ static void fuse_file_put(struct fuse_file *ff, bool sync)
 		struct fuse_req *req = ff->reserved_req;
 
 		if (sync) {
+			req->background = 0;
 			fuse_request_send(ff->fc, req);
 			path_put(&req->misc.release.path);
 			fuse_put_request(ff->fc, req);
 		} else {
 			req->end = fuse_release_end;
+			req->background = 1;
 			fuse_request_send_background(ff->fc, req);
 		}
 		kfree(ff);
@@ -282,6 +284,7 @@ void fuse_sync_release(struct fuse_file *ff, int flags)
 	WARN_ON(atomic_read(&ff->count) > 1);
 	fuse_prepare_release(ff, flags, FUSE_RELEASE);
 	ff->reserved_req->force = 1;
+	ff->reserved_req->background = 0;
 	fuse_request_send(ff->fc, ff->reserved_req);
 	fuse_put_request(ff->fc, ff->reserved_req);
 	kfree(ff);
@@ -491,9 +494,115 @@ void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
 	req->out.args[0].size = count;
 }
 
-static size_t fuse_send_read(struct fuse_req *req, struct file *file,
+static void fuse_release_user_pages(struct fuse_req *req, int write)
+{
+	unsigned i;
+
+	for (i = 0; i < req->num_pages; i++) {
+		struct page *page = req->pages[i];
+		if (write)
+			set_page_dirty_lock(page);
+		put_page(page);
+	}
+}
+
+/**
+ * In case of short read, the caller sets 'pos' to the position of
+ * actual end of fuse request in IO request. Otherwise, if bytes_requested
+ * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
+ *
+ * An example:
+ * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
+ * both submitted asynchronously. The first of them was ACKed by userspace as
+ * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
+ * second request was ACKed as short, e.g. only 1K was read, resulting in
+ * pos == 33K.
+ *
+ * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
+ * will be equal to the length of the longest contiguous fragment of
+ * transferred data starting from the beginning of IO request.
+ */
+static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
+{
+	int left;
+
+	spin_lock(&io->lock);
+	if (err)
+		io->err = io->err ? : err;
+	else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
+		io->bytes = pos;
+
+	left = --io->reqs;
+	spin_unlock(&io->lock);
+
+	if (!left) {
+		long res;
+
+		if (io->err)
+			res = io->err;
+		else if (io->bytes >= 0 && io->write)
+			res = -EIO;
+		else {
+			res = io->bytes < 0 ? io->size : io->bytes;
+
+			if (!is_sync_kiocb(io->iocb)) {
+				struct path *path = &io->iocb->ki_filp->f_path;
+				struct inode *inode = path->dentry->d_inode;
+				struct fuse_conn *fc = get_fuse_conn(inode);
+				struct fuse_inode *fi = get_fuse_inode(inode);
+
+				spin_lock(&fc->lock);
+				fi->attr_version = ++fc->attr_version;
+				spin_unlock(&fc->lock);
+			}
+		}
+
+		aio_complete(io->iocb, res, 0);
+		kfree(io);
+	}
+}
+
+static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
+{
+	struct fuse_io_priv *io = req->io;
+	ssize_t pos = -1;
+
+	fuse_release_user_pages(req, !io->write);
+
+	if (io->write) {
+		if (req->misc.write.in.size != req->misc.write.out.size)
+			pos = req->misc.write.in.offset - io->offset +
+				req->misc.write.out.size;
+	} else {
+		if (req->misc.read.in.size != req->out.args[0].size)
+			pos = req->misc.read.in.offset - io->offset +
+				req->out.args[0].size;
+	}
+
+	fuse_aio_complete(io, req->out.h.error, pos);
+}
+
+static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
+		size_t num_bytes, struct fuse_io_priv *io)
+{
+	spin_lock(&io->lock);
+	io->size += num_bytes;
+	io->reqs++;
+	spin_unlock(&io->lock);
+
+	req->io = io;
+	req->end = fuse_aio_complete_req;
+
+	__fuse_get_request(req);
+	fuse_request_send_background(fc, req);
+
+	return num_bytes;
+}
+
+static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
 			     loff_t pos, size_t count, fl_owner_t owner)
 {
+	struct file *file = io->file;
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
 
@@ -504,6 +613,10 @@ static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 		inarg->read_flags |= FUSE_READ_LOCKOWNER;
 		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 	}
+
+	if (io->async)
+		return fuse_async_req_send(fc, req, count, io);
+
 	fuse_request_send(fc, req);
 	return req->out.args[0].size;
 }
@@ -524,6 +637,7 @@ static void fuse_read_update_size(struct inode *inode, loff_t size,
 
 static int fuse_readpage(struct file *file, struct page *page)
 {
+	struct fuse_io_priv io = { .async = 0, .file = file };
 	struct inode *inode = page->mapping->host;
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	struct fuse_req *req;
@@ -556,7 +670,7 @@ static int fuse_readpage(struct file *file, struct page *page)
 	req->num_pages = 1;
 	req->pages[0] = page;
 	req->page_descs[0].length = count;
-	num_read = fuse_send_read(req, file, pos, count, NULL);
+	num_read = fuse_send_read(req, &io, pos, count, NULL);
 	err = req->out.h.error;
 	fuse_put_request(fc, req);
 
@@ -661,7 +775,12 @@ static int fuse_readpages_fill(void *_data, struct page *page)
 		int nr_alloc = min_t(unsigned, data->nr_pages,
 				     FUSE_MAX_PAGES_PER_REQ);
 		fuse_send_readpages(req, data->file);
-		data->req = req = fuse_get_req(fc, nr_alloc);
+		if (fc->async_read)
+			req = fuse_get_req_for_background(fc, nr_alloc);
+		else
+			req = fuse_get_req(fc, nr_alloc);
+
+		data->req = req;
 		if (IS_ERR(req)) {
 			unlock_page(page);
 			return PTR_ERR(req);
@@ -696,7 +815,10 @@ static int fuse_readpages(struct file *file, struct address_space *mapping,
 
 	data.file = file;
 	data.inode = inode;
-	data.req = fuse_get_req(fc, nr_alloc);
+	if (fc->async_read)
+		data.req = fuse_get_req_for_background(fc, nr_alloc);
+	else
+		data.req = fuse_get_req(fc, nr_alloc);
 	data.nr_pages = nr_pages;
 	err = PTR_ERR(data.req);
 	if (IS_ERR(data.req))
@@ -758,9 +880,10 @@ static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 	req->out.args[0].value = outarg;
 }
 
-static size_t fuse_send_write(struct fuse_req *req, struct file *file,
+static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
 			      loff_t pos, size_t count, fl_owner_t owner)
 {
+	struct file *file = io->file;
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
 	struct fuse_write_in *inarg = &req->misc.write.in;
@@ -771,6 +894,10 @@ static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 		inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 	}
+
+	if (io->async)
+		return fuse_async_req_send(fc, req, count, io);
+
 	fuse_request_send(fc, req);
 	return req->misc.write.out.size;
 }
@@ -794,11 +921,12 @@ static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
 	size_t res;
 	unsigned offset;
 	unsigned i;
+	struct fuse_io_priv io = { .async = 0, .file = file };
 
 	for (i = 0; i < req->num_pages; i++)
 		fuse_wait_on_page_writeback(inode, req->pages[i]->index);
 
-	res = fuse_send_write(req, file, pos, count, NULL);
+	res = fuse_send_write(req, &io, pos, count, NULL);
 
 	offset = req->page_descs[0].offset;
 	count = res;
@@ -1033,18 +1161,6 @@ out:
 	return written ? written : err;
 }
 
-static void fuse_release_user_pages(struct fuse_req *req, int write)
-{
-	unsigned i;
-
-	for (i = 0; i < req->num_pages; i++) {
-		struct page *page = req->pages[i];
-		if (write)
-			set_page_dirty_lock(page);
-		put_page(page);
-	}
-}
-
 static inline void fuse_page_descs_length_init(struct fuse_req *req,
 		unsigned index, unsigned nr_pages)
 {
@@ -1146,10 +1262,11 @@ static inline int fuse_iter_npages(const struct iov_iter *ii_p)
 	return min(npages, FUSE_MAX_PAGES_PER_REQ);
 }
 
-ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
+ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
 		       unsigned long nr_segs, size_t count, loff_t *ppos,
 		       int write)
 {
+	struct file *file = io->file;
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
 	size_t nmax = write ? fc->max_write : fc->max_read;
@@ -1175,11 +1292,12 @@ ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
 		}
 
 		if (write)
-			nres = fuse_send_write(req, file, pos, nbytes, owner);
+			nres = fuse_send_write(req, io, pos, nbytes, owner);
 		else
-			nres = fuse_send_read(req, file, pos, nbytes, owner);
+			nres = fuse_send_read(req, io, pos, nbytes, owner);
 
-		fuse_release_user_pages(req, !write);
+		if (!io->async)
+			fuse_release_user_pages(req, !write);
 		if (req->out.h.error) {
 			if (!res)
 				res = req->out.h.error;
@@ -1209,17 +1327,19 @@ ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
 }
 EXPORT_SYMBOL_GPL(fuse_direct_io);
 
-static ssize_t __fuse_direct_read(struct file *file, const struct iovec *iov,
-				  unsigned long nr_segs, loff_t *ppos)
+static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
+				  const struct iovec *iov,
+				  unsigned long nr_segs, loff_t *ppos,
+				  size_t count)
 {
 	ssize_t res;
+	struct file *file = io->file;
 	struct inode *inode = file_inode(file);
 
 	if (is_bad_inode(inode))
 		return -EIO;
 
-	res = fuse_direct_io(file, iov, nr_segs, iov_length(iov, nr_segs),
-			     ppos, 0);
+	res = fuse_direct_io(io, iov, nr_segs, count, ppos, 0);
 
 	fuse_invalidate_attr(inode);
 
@@ -1229,23 +1349,23 @@ static ssize_t __fuse_direct_read(struct file *file, const struct iovec *iov,
 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
 				     size_t count, loff_t *ppos)
 {
+	struct fuse_io_priv io = { .async = 0, .file = file };
 	struct iovec iov = { .iov_base = buf, .iov_len = count };
-	return __fuse_direct_read(file, &iov, 1, ppos);
+	return __fuse_direct_read(&io, &iov, 1, ppos, count);
 }
 
-static ssize_t __fuse_direct_write(struct file *file, const struct iovec *iov,
+static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
+				   const struct iovec *iov,
 				   unsigned long nr_segs, loff_t *ppos)
 {
+	struct file *file = io->file;
 	struct inode *inode = file_inode(file);
 	size_t count = iov_length(iov, nr_segs);
 	ssize_t res;
 
 	res = generic_write_checks(file, ppos, &count, 0);
-	if (!res) {
-		res = fuse_direct_io(file, iov, nr_segs, count, ppos, 1);
-		if (res > 0)
-			fuse_write_update_size(inode, *ppos);
-	}
+	if (!res)
+		res = fuse_direct_io(io, iov, nr_segs, count, ppos, 1);
 
 	fuse_invalidate_attr(inode);
 
@@ -1258,13 +1378,16 @@ static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
 	struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
 	struct inode *inode = file_inode(file);
 	ssize_t res;
+	struct fuse_io_priv io = { .async = 0, .file = file };
 
 	if (is_bad_inode(inode))
 		return -EIO;
 
 	/* Don't allow parallel writes to the same file */
 	mutex_lock(&inode->i_mutex);
-	res = __fuse_direct_write(file, &iov, 1, ppos);
+	res = __fuse_direct_write(&io, &iov, 1, ppos);
+	if (res > 0)
+		fuse_write_update_size(inode, *ppos);
 	mutex_unlock(&inode->i_mutex);
 
 	return res;
@@ -1373,6 +1496,7 @@ static int fuse_writepage_locked(struct page *page)
 	if (!req)
 		goto err;
 
+	req->background = 1; /* writeback always goes to bg_queue */
 	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 	if (!tmp_page)
 		goto err_free;
@@ -2226,21 +2350,93 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 	return 0;
 }
 
+static void fuse_do_truncate(struct file *file)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct iattr attr;
+
+	attr.ia_valid = ATTR_SIZE;
+	attr.ia_size = i_size_read(inode);
+
+	attr.ia_file = file;
+	attr.ia_valid |= ATTR_FILE;
+
+	fuse_do_setattr(inode, &attr, file);
+}
+
 static ssize_t
 fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 			loff_t offset, unsigned long nr_segs)
 {
 	ssize_t ret = 0;
-	struct file *file = NULL;
+	struct file *file = iocb->ki_filp;
+	struct fuse_file *ff = file->private_data;
 	loff_t pos = 0;
+	struct inode *inode;
+	loff_t i_size;
+	size_t count = iov_length(iov, nr_segs);
+	struct fuse_io_priv *io;
 
-	file = iocb->ki_filp;
 	pos = offset;
+	inode = file->f_mapping->host;
+	i_size = i_size_read(inode);
+
+	/* optimization for short read */
+	if (rw != WRITE && offset + count > i_size) {
+		if (offset >= i_size)
+			return 0;
+		count = i_size - offset;
+	}
+
+	io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
+	if (!io)
+		return -ENOMEM;
+	spin_lock_init(&io->lock);
+	io->reqs = 1;
+	io->bytes = -1;
+	io->size = 0;
+	io->offset = offset;
+	io->write = (rw == WRITE);
+	io->err = 0;
+	io->file = file;
+	/*
+	 * By default, we want to optimize all I/Os with async request
+	 * submission to the client filesystem if supported.
+	 */
+	io->async = ff->fc->async_dio;
+	io->iocb = iocb;
+
+	/*
+	 * We cannot asynchronously extend the size of a file. We have no method
+	 * to wait on real async I/O requests, so we must submit this request
+	 * synchronously.
+	 */
+	if (!is_sync_kiocb(iocb) && (offset + count > i_size))
+		io->async = false;
 
 	if (rw == WRITE)
-		ret = __fuse_direct_write(file, iov, nr_segs, &pos);
+		ret = __fuse_direct_write(io, iov, nr_segs, &pos);
 	else
-		ret = __fuse_direct_read(file, iov, nr_segs, &pos);
+		ret = __fuse_direct_read(io, iov, nr_segs, &pos, count);
+
+	if (io->async) {
+		fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
+
+		/* we have a non-extending, async request, so return */
+		if (ret > 0 && !is_sync_kiocb(iocb))
+			return -EIOCBQUEUED;
+
+		ret = wait_on_sync_kiocb(iocb);
+	} else {
+		kfree(io);
+	}
+
+	if (rw == WRITE) {
+		if (ret > 0)
+			fuse_write_update_size(inode, pos);
+		else if (ret < 0 && offset + count > i_size)
+			fuse_do_truncate(file);
+	}
 
 	return ret;
 }