Commit 91ec6c85 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

Revert "fuse: in fuse_flush only wait if someone wants the return code" 



This reverts commit 5a8bee63.

Jürg Billeter reports the following regression:

  Since v6.3-rc1 commit 5a8bee63 ("fuse: in fuse_flush only wait if
  someone wants the return code") `fput()` is called asynchronously if a
  file is closed as part of a process exiting, i.e., if there was no
  explicit `close()` before exit.

  If the file was open for writing, also `put_write_access()` is called
  asynchronously as part of the async `fput()`.

  If that newly written file is an executable, attempting to `execve()` the
  new file can fail with `ETXTBSY` if it's called after the writer process
  exited but before the async `fput()` has run.

Reported-and-tested-by: default avatar"Jürg Billeter" <j@bitron.ch>
Cc: <stable@vger.kernel.org> # v6.3
Link: https://lore.kernel.org/all/4f66cded234462964899f2a661750d6798a57ec0.camel@bitron.ch/


Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 2ccdd1b1

fs/fuse/file.c

+26 −63
Original line number Diff line number Diff line
@@ -19,7 +19,6 @@ 
#include <linux/uio.h>

#include <linux/fs.h>

#include <linux/filelock.h>

#include <linux/file.h>



static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,

			  unsigned int open_flags, int opcode,
@@ -479,36 +478,48 @@ static void fuse_sync_writes(struct inode *inode) 
	fuse_release_nowrite(inode);

}



struct fuse_flush_args {

	struct fuse_args args;

	struct fuse_flush_in inarg;

	struct work_struct work;

	struct file *file;

};



static int fuse_do_flush(struct fuse_flush_args *fa)

static int fuse_flush(struct file *file, fl_owner_t id)

{

	int err;

	struct inode *inode = file_inode(fa->file);

	struct inode *inode = file_inode(file);

	struct fuse_mount *fm = get_fuse_mount(inode);

	struct fuse_file *ff = file->private_data;

	struct fuse_flush_in inarg;

	FUSE_ARGS(args);

	int err;



	if (fuse_is_bad(inode))

		return -EIO;



	if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)

		return 0;



	err = write_inode_now(inode, 1);

	if (err)

		goto out;

		return err;



	inode_lock(inode);

	fuse_sync_writes(inode);

	inode_unlock(inode);



	err = filemap_check_errors(fa->file->f_mapping);

	err = filemap_check_errors(file->f_mapping);

	if (err)

		goto out;

		return err;



	err = 0;

	if (fm->fc->no_flush)

		goto inval_attr_out;



	err = fuse_simple_request(fm, &fa->args);

	memset(&inarg, 0, sizeof(inarg));

	inarg.fh = ff->fh;

	inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);

	args.opcode = FUSE_FLUSH;

	args.nodeid = get_node_id(inode);

	args.in_numargs = 1;

	args.in_args[0].size = sizeof(inarg);

	args.in_args[0].value = &inarg;

	args.force = true;



	err = fuse_simple_request(fm, &args);

	if (err == -ENOSYS) {

		fm->fc->no_flush = 1;

		err = 0;
@@ -521,57 +532,9 @@ static int fuse_do_flush(struct fuse_flush_args *fa) 
	 */

	if (!err && fm->fc->writeback_cache)

		fuse_invalidate_attr_mask(inode, STATX_BLOCKS);



out:

	fput(fa->file);

	kfree(fa);

	return err;

}



static void fuse_flush_async(struct work_struct *work)

{

	struct fuse_flush_args *fa = container_of(work, typeof(*fa), work);



	fuse_do_flush(fa);

}



static int fuse_flush(struct file *file, fl_owner_t id)

{

	struct fuse_flush_args *fa;

	struct inode *inode = file_inode(file);

	struct fuse_mount *fm = get_fuse_mount(inode);

	struct fuse_file *ff = file->private_data;



	if (fuse_is_bad(inode))

		return -EIO;



	if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)

		return 0;



	fa = kzalloc(sizeof(*fa), GFP_KERNEL);

	if (!fa)

		return -ENOMEM;



	fa->inarg.fh = ff->fh;

	fa->inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);

	fa->args.opcode = FUSE_FLUSH;

	fa->args.nodeid = get_node_id(inode);

	fa->args.in_numargs = 1;

	fa->args.in_args[0].size = sizeof(fa->inarg);

	fa->args.in_args[0].value = &fa->inarg;

	fa->args.force = true;

	fa->file = get_file(file);



	/* Don't wait if the task is exiting */

	if (current->flags & PF_EXITING) {

		INIT_WORK(&fa->work, fuse_flush_async);

		schedule_work(&fa->work);

		return 0;

	}



	return fuse_do_flush(fa);

}



int fuse_fsync_common(struct file *file, loff_t start, loff_t end,

		      int datasync, int opcode)

{