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Commit af04fadc authored by Al Viro's avatar Al Viro Committed by Linus Torvalds
Browse files

Revert "fs: fold open_check_o_direct into do_dentry_open" 



This reverts commit cab64df1.

Having vfs_open() in some cases drop the reference to
struct file combined with

	error = vfs_open(path, f, cred);
	if (error) {
		put_filp(f);
		return ERR_PTR(error);
	}
	return f;

is flat-out wrong.  It used to be

		error = vfs_open(path, f, cred);
		if (!error) {
			/* from now on we need fput() to dispose of f */
			error = open_check_o_direct(f);
			if (error) {
				fput(f);
				f = ERR_PTR(error);
			}
		} else {
			put_filp(f);
			f = ERR_PTR(error);
		}

and sure, having that open_check_o_direct() boilerplate gotten rid of is
nice, but not that way...

Worse, another call chain (via finish_open()) is FUBAR now wrt
FILE_OPENED handling - in that case we get error returned, with file
already hit by fput() *AND* FILE_OPENED not set.  Guess what happens in
path_openat(), when it hits

	if (!(opened & FILE_OPENED)) {
		BUG_ON(!error);
		put_filp(file);
	}

The root cause of all that crap is that the callers of do_dentry_open()
have no way to tell which way did it fail; while that could be fixed up
(by passing something like int *opened to do_dentry_open() and have it
marked if we'd called ->open()), it's probably much too late in the
cycle to do so right now.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4faa9996

fs/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -125,6 +125,7 @@ int do_fchmodat(int dfd, const char __user *filename, umode_t mode); 
int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,

		int flag);



extern int open_check_o_direct(struct file *f);

extern int vfs_open(const struct path *, struct file *, const struct cred *);

extern struct file *filp_clone_open(struct file *);

fs/namei.c

+6 −1
Original line number Diff line number Diff line
@@ -3367,6 +3367,8 @@ static int do_last(struct nameidata *nd, 
		goto out;

	*opened |= FILE_OPENED;

opened:

	error = open_check_o_direct(file);

	if (!error)

		error = ima_file_check(file, op->acc_mode, *opened);

	if (!error && will_truncate)

		error = handle_truncate(file);
@@ -3447,6 +3449,9 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags, 
	error = finish_open(file, child, NULL, opened);

	if (error)

		goto out2;

	error = open_check_o_direct(file);

	if (error)

		fput(file);

out2:

	mnt_drop_write(path.mnt);

out:

fs/open.c

+26 −18
Original line number Diff line number Diff line
@@ -724,6 +724,16 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group) 
	return ksys_fchown(fd, user, group);

}



int open_check_o_direct(struct file *f)

{

	/* NB: we're sure to have correct a_ops only after f_op->open */

	if (f->f_flags & O_DIRECT) {

		if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)

			return -EINVAL;

	}

	return 0;

}



static int do_dentry_open(struct file *f,

			  struct inode *inode,

			  int (*open)(struct inode *, struct file *),
@@ -745,7 +755,7 @@ static int do_dentry_open(struct file *f, 
	if (unlikely(f->f_flags & O_PATH)) {

		f->f_mode = FMODE_PATH;

		f->f_op = &empty_fops;

		goto done;

		return 0;

	}



	if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
@@ -798,12 +808,7 @@ static int do_dentry_open(struct file *f, 
	f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);



	file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);

done:

	/* NB: we're sure to have correct a_ops only after f_op->open */

	error = -EINVAL;

	if ((f->f_flags & O_DIRECT) &&

	    (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO))

	    	goto out_fput;



	return 0;



cleanup_all:
@@ -818,9 +823,6 @@ static int do_dentry_open(struct file *f, 
	f->f_path.dentry = NULL;

	f->f_inode = NULL;

	return error;

out_fput:

    	fput(f);

	return error;

}



/**
@@ -918,14 +920,20 @@ struct file *dentry_open(const struct path *path, int flags, 
	BUG_ON(!path->mnt);



	f = get_empty_filp();

	if (IS_ERR(f))

		return f;



	if (!IS_ERR(f)) {

		f->f_flags = flags;

		error = vfs_open(path, f, cred);

		if (!error) {

			/* from now on we need fput() to dispose of f */

			error = open_check_o_direct(f);

			if (error) {

				fput(f);

				f = ERR_PTR(error);

			}

		} else { 

			put_filp(f);

		return ERR_PTR(error);

			f = ERR_PTR(error);

		}

	}

	return f;

}