Merge tag 'fuse-update-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:

 - Fix a page locking bug in write (introduced in 2.6.26)

 - Allow sgid bit to be killed in setacl()

 - Miscellaneous fixes and cleanups

* tag 'fuse-update-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  cuse: simplify refcount
  cuse: prevent clone
  virtiofs: fix userns
  virtiofs: remove useless function
  virtiofs: split requests that exceed virtqueue size
  virtiofs: fix memory leak in virtio_fs_probe()
  fuse: invalidate attrs when page writeback completes
  fuse: add a flag FUSE_SETXATTR_ACL_KILL_SGID to kill SGID
  fuse: extend FUSE_SETXATTR request
  fuse: fix matching of FUSE_DEV_IOC_CLONE command
  fuse: fix a typo
  fuse: don't zero pages twice
  fuse: fix typo for fuse_conn.max_pages comment
  fuse: fix write deadlock

1 files changed, 44 insertions, 27 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index e8aa5337eb29..09ef2a4d25ed 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -802,21 +802,12 @@ static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
-	if (fc->writeback_cache) {
-		/*
-		 * A hole in a file. Some data after the hole are in page cache,
-		 * but have not reached the client fs yet. So, the hole is not
-		 * present there.
-		 */
-		int i;
-		int start_idx = num_read >> PAGE_SHIFT;
-		size_t off = num_read & (PAGE_SIZE - 1);
-
-		for (i = start_idx; i < ap->num_pages; i++) {
-			zero_user_segment(ap->pages[i], off, PAGE_SIZE);
-			off = 0;
-		}
-	} else {
+	/*
+	 * If writeback_cache is enabled, a short read means there's a hole in
+	 * the file.  Some data after the hole is in page cache, but has not
+	 * reached the client fs yet.  So the hole is not present there.
+	 */
+	if (!fc->writeback_cache) {
 		loff_t pos = page_offset(ap->pages[0]) + num_read;
 		fuse_read_update_size(inode, pos, attr_ver);
 	}
@@ -1103,6 +1094,7 @@ static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
 	struct fuse_file *ff = file->private_data;
 	struct fuse_mount *fm = ff->fm;
 	unsigned int offset, i;
+	bool short_write;
 	int err;
 
 	for (i = 0; i < ap->num_pages; i++)
@@ -1117,32 +1109,38 @@ static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
 	if (!err && ia->write.out.size > count)
 		err = -EIO;
 
+	short_write = ia->write.out.size < count;
 	offset = ap->descs[0].offset;
 	count = ia->write.out.size;
 	for (i = 0; i < ap->num_pages; i++) {
 		struct page *page = ap->pages[i];
 
-		if (!err && !offset && count >= PAGE_SIZE)
-			SetPageUptodate(page);
-
-		if (count > PAGE_SIZE - offset)
-			count -= PAGE_SIZE - offset;
-		else
-			count = 0;
-		offset = 0;
-
-		unlock_page(page);
+		if (err) {
+			ClearPageUptodate(page);
+		} else {
+			if (count >= PAGE_SIZE - offset)
+				count -= PAGE_SIZE - offset;
+			else {
+				if (short_write)
+					ClearPageUptodate(page);
+				count = 0;
+			}
+			offset = 0;
+		}
+		if (ia->write.page_locked && (i == ap->num_pages - 1))
+			unlock_page(page);
 		put_page(page);
 	}
 
 	return err;
 }
 
-static ssize_t fuse_fill_write_pages(struct fuse_args_pages *ap,
+static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
 				     struct address_space *mapping,
 				     struct iov_iter *ii, loff_t pos,
 				     unsigned int max_pages)
 {
+	struct fuse_args_pages *ap = &ia->ap;
 	struct fuse_conn *fc = get_fuse_conn(mapping->host);
 	unsigned offset = pos & (PAGE_SIZE - 1);
 	size_t count = 0;
@@ -1195,6 +1193,16 @@ static ssize_t fuse_fill_write_pages(struct fuse_args_pages *ap,
 		if (offset == PAGE_SIZE)
 			offset = 0;
 
+		/* If we copied full page, mark it uptodate */
+		if (tmp == PAGE_SIZE)
+			SetPageUptodate(page);
+
+		if (PageUptodate(page)) {
+			unlock_page(page);
+		} else {
+			ia->write.page_locked = true;
+			break;
+		}
 		if (!fc->big_writes)
 			break;
 	} while (iov_iter_count(ii) && count < fc->max_write &&
@@ -1238,7 +1246,7 @@ static ssize_t fuse_perform_write(struct kiocb *iocb,
 			break;
 		}
 
-		count = fuse_fill_write_pages(ap, mapping, ii, pos, nr_pages);
+		count = fuse_fill_write_pages(&ia, mapping, ii, pos, nr_pages);
 		if (count <= 0) {
 			err = count;
 		} else {
@@ -1753,8 +1761,17 @@ static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
 		container_of(args, typeof(*wpa), ia.ap.args);
 	struct inode *inode = wpa->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
+	struct fuse_conn *fc = get_fuse_conn(inode);
 
 	mapping_set_error(inode->i_mapping, error);
+	/*
+	 * A writeback finished and this might have updated mtime/ctime on
+	 * server making local mtime/ctime stale.  Hence invalidate attrs.
+	 * Do this only if writeback_cache is not enabled.  If writeback_cache
+	 * is enabled, we trust local ctime/mtime.
+	 */
+	if (!fc->writeback_cache)
+		fuse_invalidate_attr(inode);
 	spin_lock(&fi->lock);
 	rb_erase(&wpa->writepages_entry, &fi->writepages);
 	while (wpa->next) {