fuse: handle synchronous iocbs internally

Based on a patch from Maxim Patlasov <MPatlasov@parallels.com>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index c01ec3bdcfd81090fae2cb26ae166f351d4505eb..f81d83eb9758e52216ac5d33c47e0ed20cfd6798 100644 (file)
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -528,6 +528,17 @@ static void fuse_release_user_pages(struct fuse_req *req, int write)
        }
 }
 
+static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
+{
+       if (io->err)
+               return io->err;
+
+       if (io->bytes >= 0 && io->write)
+               return -EIO;
+
+       return io->bytes < 0 ? io->size : io->bytes;
+}
+
 /**
  * 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
@@ -546,6 +557,7 @@ static void fuse_release_user_pages(struct fuse_req *req, int write)
  */
 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
 {
+       bool is_sync = is_sync_kiocb(io->iocb);
        int left;
 
        spin_lock(&io->lock);
@@ -555,27 +567,21 @@ static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
                io->bytes = pos;
 
        left = --io->reqs;
+       if (!left && is_sync)
+               complete(io->done);
        spin_unlock(&io->lock);
 
-       if (!left) {
-               long res;
+       if (!left && !is_sync) {
+               ssize_t res = fuse_get_res_by_io(io);
 
-               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 (res >= 0) {
+                       struct inode *inode = file_inode(io->iocb->ki_filp);
+                       struct fuse_conn *fc = get_fuse_conn(inode);
+                       struct fuse_inode *fi = get_fuse_inode(inode);
 
-                       if (!is_sync_kiocb(io->iocb)) {
-                               struct inode *inode = file_inode(io->iocb->ki_filp);
-                               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);
-                       }
+                       spin_lock(&fc->lock);
+                       fi->attr_version = ++fc->attr_version;
+                       spin_unlock(&fc->lock);
                }
 
                aio_complete(io->iocb, res, 0);
@@ -2801,6 +2807,7 @@ static ssize_t
 fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
                        loff_t offset)
 {
+       DECLARE_COMPLETION_ONSTACK(wait);
        ssize_t ret = 0;
        struct file *file = iocb->ki_filp;
        struct fuse_file *ff = file->private_data;
@@ -2852,6 +2859,9 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
        if (!is_sync_kiocb(iocb) && (offset + count > i_size) && rw == WRITE)
                io->async = false;
 
+       if (io->async && is_sync_kiocb(iocb))
+               io->done = &wait;
+
        if (rw == WRITE)
                ret = __fuse_direct_write(io, iter, &pos);
        else
@@ -2864,11 +2874,12 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
                if (!is_sync_kiocb(iocb))
                        return -EIOCBQUEUED;
 
-               ret = wait_on_sync_kiocb(iocb);
-       } else {
-               kfree(io);
+               wait_for_completion(&wait);
+               ret = fuse_get_res_by_io(io);
        }
 
+       kfree(io);
+
        if (rw == WRITE) {
                if (ret > 0)
                        fuse_write_update_size(inode, pos);

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 1cdfb07c1376b4f4b5633e86fdbdfc4320953de2..7354dc142a50845a62e9a413d82d185afc1f5b0d 100644 (file)
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -263,6 +263,7 @@ struct fuse_io_priv {
        int err;
        struct kiocb *iocb;
        struct file *file;
+       struct completion *done;
 };
 
 /**