Commit d66907b5 authored by Amir Goldstein's avatar Amir Goldstein
Browse files

ovl: convert ovl_real_fdget() callers to ovl_real_file() 



Stop using struct fd to return a real file from ovl_real_fdget(),
because we no longer return a temporary file object and the callers
always get a borrowed file reference.

Rename the helper to ovl_real_file(), return a borrowed reference of
the real file that is referenced from the overlayfs file or an error.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
parent 4333e42e

fs/overlayfs/file.c

+59 −84
Original line number Diff line number Diff line
@@ -195,16 +195,6 @@ static struct file *ovl_real_file(const struct file *file) 
	return ovl_real_file_path(file, &realpath);

}



static int ovl_real_fdget(const struct file *file, struct fd *real)

{

	struct file *f = ovl_real_file(file);



	if (IS_ERR(f))

		return PTR_ERR(f);

	real->word = (unsigned long)f;

	return 0;

}



static int ovl_open(struct inode *inode, struct file *file)

{

	struct dentry *dentry = file_dentry(file);
@@ -253,7 +243,7 @@ static int ovl_release(struct inode *inode, struct file *file) 
static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)

{

	struct inode *inode = file_inode(file);

	struct fd real;

	struct file *realfile;

	const struct cred *old_cred;

	loff_t ret;
@@ -269,9 +259,9 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence) 
			return vfs_setpos(file, 0, 0);

	}



	ret = ovl_real_fdget(file, &real);

	if (ret)

		return ret;

	realfile = ovl_real_file(file);

	if (IS_ERR(realfile))

		return PTR_ERR(realfile);



	/*

	 * Overlay file f_pos is the master copy that is preserved
@@ -281,17 +271,15 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence) 
	 * files, so we use the real file to perform seeks.

	 */

	ovl_inode_lock(inode);

	fd_file(real)->f_pos = file->f_pos;

	realfile->f_pos = file->f_pos;



	old_cred = ovl_override_creds(inode->i_sb);

	ret = vfs_llseek(fd_file(real), offset, whence);

	ret = vfs_llseek(realfile, offset, whence);

	ovl_revert_creds(old_cred);



	file->f_pos = fd_file(real)->f_pos;

	file->f_pos = realfile->f_pos;

	ovl_inode_unlock(inode);



	fdput(real);



	return ret;

}
@@ -337,8 +325,7 @@ static void ovl_file_accessed(struct file *file) 
static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)

{

	struct file *file = iocb->ki_filp;

	struct fd real;

	ssize_t ret;

	struct file *realfile;

	struct backing_file_ctx ctx = {

		.cred = ovl_creds(file_inode(file)->i_sb),

		.accessed = ovl_file_accessed,
@@ -347,22 +334,19 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
	if (!iov_iter_count(iter))

		return 0;



	ret = ovl_real_fdget(file, &real);

	if (ret)

		return ret;

	realfile = ovl_real_file(file);

	if (IS_ERR(realfile))

		return PTR_ERR(realfile);



	ret = backing_file_read_iter(fd_file(real), iter, iocb, iocb->ki_flags,

	return backing_file_read_iter(realfile, iter, iocb, iocb->ki_flags,

				      &ctx);

	fdput(real);



	return ret;

}



static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)

{

	struct file *file = iocb->ki_filp;

	struct inode *inode = file_inode(file);

	struct fd real;

	struct file *realfile;

	ssize_t ret;

	int ifl = iocb->ki_flags;

	struct backing_file_ctx ctx = {
@@ -377,8 +361,9 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) 
	/* Update mode */

	ovl_copyattr(inode);



	ret = ovl_real_fdget(file, &real);

	if (ret)

	realfile = ovl_real_file(file);

	ret = PTR_ERR(realfile);

	if (IS_ERR(realfile))

		goto out_unlock;



	if (!ovl_should_sync(OVL_FS(inode->i_sb)))
@@ -389,8 +374,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) 
	 * this property in case it is set by the issuer.

	 */

	ifl &= ~IOCB_DIO_CALLER_COMP;

	ret = backing_file_write_iter(fd_file(real), iter, iocb, ifl, &ctx);

	fdput(real);

	ret = backing_file_write_iter(realfile, iter, iocb, ifl, &ctx);



out_unlock:

	inode_unlock(inode);
@@ -402,7 +386,7 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos, 
			       struct pipe_inode_info *pipe, size_t len,

			       unsigned int flags)

{

	struct fd real;

	struct file *realfile;

	ssize_t ret;

	struct backing_file_ctx ctx = {

		.cred = ovl_creds(file_inode(in)->i_sb),
@@ -410,15 +394,14 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos, 
	};

	struct kiocb iocb;



	ret = ovl_real_fdget(in, &real);

	if (ret)

		return ret;

	realfile = ovl_real_file(in);

	if (IS_ERR(realfile))

		return PTR_ERR(realfile);



	init_sync_kiocb(&iocb, in);

	iocb.ki_pos = *ppos;

	ret = backing_file_splice_read(fd_file(real), &iocb, pipe, len, flags, &ctx);

	ret = backing_file_splice_read(realfile, &iocb, pipe, len, flags, &ctx);

	*ppos = iocb.ki_pos;

	fdput(real);



	return ret;

}
@@ -426,7 +409,7 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos, 
/*

 * Calling iter_file_splice_write() directly from overlay's f_op may deadlock

 * due to lock order inversion between pipe->mutex in iter_file_splice_write()

 * and file_start_write(fd_file(real)) in ovl_write_iter().

 * and file_start_write(realfile) in ovl_write_iter().

 *

 * So do everything ovl_write_iter() does and call iter_file_splice_write() on

 * the real file.
@@ -434,7 +417,7 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos, 
static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,

				loff_t *ppos, size_t len, unsigned int flags)

{

	struct fd real;

	struct file *realfile;

	struct inode *inode = file_inode(out);

	ssize_t ret;

	struct backing_file_ctx ctx = {
@@ -447,16 +430,15 @@ static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out, 
	/* Update mode */

	ovl_copyattr(inode);



	ret = ovl_real_fdget(out, &real);

	if (ret)

	realfile = ovl_real_file(out);

	ret = PTR_ERR(realfile);

	if (IS_ERR(realfile))

		goto out_unlock;



	init_sync_kiocb(&iocb, out);

	iocb.ki_pos = *ppos;

	ret = backing_file_splice_write(pipe, fd_file(real), &iocb, len, flags, &ctx);

	ret = backing_file_splice_write(pipe, realfile, &iocb, len, flags, &ctx);

	*ppos = iocb.ki_pos;

	fdput(real);





out_unlock:

	inode_unlock(inode);
@@ -508,7 +490,7 @@ static int ovl_mmap(struct file *file, struct vm_area_struct *vma) 
static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)

{

	struct inode *inode = file_inode(file);

	struct fd real;

	struct file *realfile;

	const struct cred *old_cred;

	int ret;
@@ -519,19 +501,18 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len 
	if (ret)

		goto out_unlock;



	ret = ovl_real_fdget(file, &real);

	if (ret)

	realfile = ovl_real_file(file);

	ret = PTR_ERR(realfile);

	if (IS_ERR(realfile))

		goto out_unlock;



	old_cred = ovl_override_creds(file_inode(file)->i_sb);

	ret = vfs_fallocate(fd_file(real), mode, offset, len);

	ret = vfs_fallocate(realfile, mode, offset, len);

	ovl_revert_creds(old_cred);



	/* Update size */

	ovl_file_modified(file);



	fdput(real);



out_unlock:

	inode_unlock(inode);
@@ -540,20 +521,18 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len 


static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)

{

	struct fd real;

	struct file *realfile;

	const struct cred *old_cred;

	int ret;



	ret = ovl_real_fdget(file, &real);

	if (ret)

		return ret;

	realfile = ovl_real_file(file);

	if (IS_ERR(realfile))

		return PTR_ERR(realfile);



	old_cred = ovl_override_creds(file_inode(file)->i_sb);

	ret = vfs_fadvise(fd_file(real), offset, len, advice);

	ret = vfs_fadvise(realfile, offset, len, advice);

	ovl_revert_creds(old_cred);



	fdput(real);



	return ret;

}
@@ -568,7 +547,7 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in, 
			    loff_t len, unsigned int flags, enum ovl_copyop op)

{

	struct inode *inode_out = file_inode(file_out);

	struct fd real_in, real_out;

	struct file *realfile_in, *realfile_out;

	const struct cred *old_cred;

	loff_t ret;
@@ -581,31 +560,31 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in, 
			goto out_unlock;

	}



	ret = ovl_real_fdget(file_out, &real_out);

	if (ret)

	realfile_out = ovl_real_file(file_out);

	ret = PTR_ERR(realfile_out);

	if (IS_ERR(realfile_out))

		goto out_unlock;



	ret = ovl_real_fdget(file_in, &real_in);

	if (ret) {

		fdput(real_out);

	realfile_in = ovl_real_file(file_in);

	ret = PTR_ERR(realfile_in);

	if (IS_ERR(realfile_in))

		goto out_unlock;

	}



	old_cred = ovl_override_creds(file_inode(file_out)->i_sb);

	switch (op) {

	case OVL_COPY:

		ret = vfs_copy_file_range(fd_file(real_in), pos_in,

					  fd_file(real_out), pos_out, len, flags);

		ret = vfs_copy_file_range(realfile_in, pos_in,

					  realfile_out, pos_out, len, flags);

		break;



	case OVL_CLONE:

		ret = vfs_clone_file_range(fd_file(real_in), pos_in,

					   fd_file(real_out), pos_out, len, flags);

		ret = vfs_clone_file_range(realfile_in, pos_in,

					   realfile_out, pos_out, len, flags);

		break;



	case OVL_DEDUPE:

		ret = vfs_dedupe_file_range_one(fd_file(real_in), pos_in,

						fd_file(real_out), pos_out, len,

		ret = vfs_dedupe_file_range_one(realfile_in, pos_in,

						realfile_out, pos_out, len,

						flags);

		break;

	}
@@ -614,9 +593,6 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in, 
	/* Update size */

	ovl_file_modified(file_out);



	fdput(real_in);

	fdput(real_out);



out_unlock:

	inode_unlock(inode_out);
@@ -660,20 +636,19 @@ static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in, 


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

{

	struct fd real;

	struct file *realfile;

	const struct cred *old_cred;

	int err;

	int err = 0;



	err = ovl_real_fdget(file, &real);

	if (err)

		return err;

	realfile = ovl_real_file(file);

	if (IS_ERR(realfile))

		return PTR_ERR(realfile);



	if (fd_file(real)->f_op->flush) {

	if (realfile->f_op->flush) {

		old_cred = ovl_override_creds(file_inode(file)->i_sb);

		err = fd_file(real)->f_op->flush(fd_file(real), id);

		err = realfile->f_op->flush(realfile, id);

		ovl_revert_creds(old_cred);

	}

	fdput(real);



	return err;

}