Merge tag 'fuse-update-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:

 - Add mechanism for cleaning out unused, stale dentries; controlled via
   a module option (Luis Henriques)

 - Fix various bugs

 - Cleanups

* tag 'fuse-update-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: Uninitialized variable in fuse_epoch_work()
  fuse: fix io-uring list corruption for terminated non-committed requests
  fuse: signal that a fuse inode should exhibit local fs behaviors
  fuse: Always flush the page cache before FOPEN_DIRECT_IO write
  fuse: Invalidate the page cache after FOPEN_DIRECT_IO write
  fuse: rename 'namelen' to 'namesize'
  fuse: use strscpy instead of strcpy
  fuse: refactor fuse_conn_put() to remove negative logic.
  fuse: new work queue to invalidate dentries from old epochs
  fuse: new work queue to periodically invalidate expired dentries
  dcache: export shrink_dentry_list() and add new helper d_dispose_if_unused()
  fuse: add WARN_ON and comment for RCU revalidate
  fuse: Fix whitespace for fuse_uring_args_to_ring() comment
  fuse: missing copy_finish in fuse-over-io-uring argument copies
  fuse: fix readahead reclaim deadlock

1 files changed, 29 insertions, 8 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 7bcb650a9f26..01bc894e9c2b 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -110,7 +110,9 @@ static void fuse_file_put(struct fuse_file *ff, bool sync)
 			fuse_file_io_release(ff, ra->inode);
 
 		if (!args) {
-			/* Do nothing when server does not implement 'open' */
+			/* Do nothing when server does not implement 'opendir' */
+		} else if (args->opcode == FUSE_RELEASE && ff->fm->fc->no_open) {
+			fuse_release_end(ff->fm, args, 0);
 		} else if (sync) {
 			fuse_simple_request(ff->fm, args);
 			fuse_release_end(ff->fm, args, 0);
@@ -131,8 +133,17 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
 	struct fuse_file *ff;
 	int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
 	bool open = isdir ? !fc->no_opendir : !fc->no_open;
+	bool release = !isdir || open;
 
-	ff = fuse_file_alloc(fm, open);
+	/*
+	 * ff->args->release_args still needs to be allocated (so we can hold an
+	 * inode reference while there are pending inflight file operations when
+	 * ->release() is called, see fuse_prepare_release()) even if
+	 * fc->no_open is set else it becomes possible for reclaim to deadlock
+	 * if while servicing the readahead request the server triggers reclaim
+	 * and reclaim evicts the inode of the file being read ahead.
+	 */
+	ff = fuse_file_alloc(fm, release);
 	if (!ff)
 		return ERR_PTR(-ENOMEM);
 
@@ -152,13 +163,14 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
 			fuse_file_free(ff);
 			return ERR_PTR(err);
 		} else {
-			/* No release needed */
-			kfree(ff->args);
-			ff->args = NULL;
-			if (isdir)
+			if (isdir) {
+				/* No release needed */
+				kfree(ff->args);
+				ff->args = NULL;
 				fc->no_opendir = 1;
-			else
+			} else {
 				fc->no_open = 1;
+			}
 		}
 	}
 
@@ -1652,7 +1664,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 	if (!ia)
 		return -ENOMEM;
 
-	if (fopen_direct_io && fc->direct_io_allow_mmap) {
+	if (fopen_direct_io) {
 		res = filemap_write_and_wait_range(mapping, pos, pos + count - 1);
 		if (res) {
 			fuse_io_free(ia);
@@ -1726,6 +1738,15 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 	if (res > 0)
 		*ppos = pos;
 
+	if (res > 0 && write && fopen_direct_io) {
+		/*
+		 * As in generic_file_direct_write(), invalidate after the
+		 * write, to invalidate read-ahead cache that may have competed
+		 * with the write.
+		 */
+		invalidate_inode_pages2_range(mapping, idx_from, idx_to);
+	}
+
 	return res > 0 ? res : err;
 }
 EXPORT_SYMBOL_GPL(fuse_direct_io);