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From: Al Viro <viro@zeniv.linux.org.uk>
To: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	pali@kernel.org, dsterba@suse.cz, aaptel@suse.com,
	willy@infradead.org, rdunlap@infradead.org, joe@perches.com,
	mark@harmstone.com
Subject: Re: [PATCH v3 04/10] fs/ntfs3: Add file operations and implementation
Date: Fri, 28 Aug 2020 16:55:31 +0100	[thread overview]
Message-ID: <20200828155531.GK1236603@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200828143938.102889-5-almaz.alexandrovich@paragon-software.com>

On Fri, Aug 28, 2020 at 07:39:32AM -0700, Konstantin Komarov wrote:

> +static int ntfs_atomic_open(struct inode *dir, struct dentry *dentry,
> +			    struct file *file, u32 flags, umode_t mode)
> +{
> +	int err;
> +	bool excl = !!(flags & O_EXCL);
> +	struct inode *inode;
> +	struct ntfs_fnd *fnd = NULL;
> +	struct ntfs_inode *ni = ntfs_i(dir);
> +
> +	ni_lock(ni);
> +
> +	if (d_in_lookup(dentry)) {
> +		struct dentry *d;
> +
> +		fnd = fnd_get(&ntfs_i(dir)->dir);
> +		if (!fnd) {
> +			err = -ENOMEM;
> +			goto out;
> +		}
> +
> +		d = __ntfs_lookup(dir, dentry, fnd);
> +		if (IS_ERR(d)) {
> +			err = PTR_ERR(d);
> +			d = NULL;
> +			goto out1;
> +		}
> +
> +		if (d)
> +			dentry = d;
> +
> +		if (d_really_is_positive(dentry)) {
> +			if (file->f_mode & FMODE_OPENED) {

	How do we get FMODE_OPENED here?

> +				dput(d);
> +				err = 0;
> +			} else
> +				err = finish_no_open(file, d);
> +			goto out1;
> +		}
> +		WARN_ON(d);
> +	}
> +
> +	if (!(flags & O_CREAT)) {
> +		err = -ENOENT;
> +		goto out1;
> +	}

	Just return finish_no_open() in that case.  And let the caller handle
that.

> +	err = ntfs_create_inode(dir, dentry, file, mode, 0, NULL, 0, excl, fnd,
> +				&inode);
> +
> +out1:
> +	fnd_put(fnd);
> +out:
> +	ni_unlock(ni);
> +
> +	return err;
> +}

BTW, what's the point of that ni_lock() here?  d_in_lookup() is stable
regardless of that and any attempts to create something in the parent
are serialized by ->i_rwsem.  If you want it around the actual file
creation, why not take it just there, and replace the open-coded
ntfs_lookup() with the call of the real thing?  As in
	if (d_in_lookup(dentry)) {
		d = ntfs_lookup(....);
		if (IS_ERR(d))
			return d;
		if (d)
			dentry = d;
	}
        if (!(flags & O_CREAT) || d_really_is_positive(dentry))
		return finish_no_open(file, d);
	/* deal with creation of file */
	ni_lock(...);
	....

  parent reply	other threads:[~2020-08-28 15:55 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-28 14:39 [PATCH v3 00/10] NTFS read-write driver GPL implementation by Paragon Software Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 01/10] fs/ntfs3: Add headers and misc files Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 02/10] fs/ntfs3: Add initialization of super block Konstantin Komarov
2020-09-04 12:06   ` Pali Rohár
2020-09-11 16:59     ` Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 03/10] fs/ntfs3: Add bitmap Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 04/10] fs/ntfs3: Add file operations and implementation Konstantin Komarov
2020-08-28 15:45   ` Al Viro
2020-09-04 12:41     ` Konstantin Komarov
2020-08-28 15:55   ` Al Viro [this message]
2020-09-04 12:49     ` Konstantin Komarov
2020-09-04 11:50   ` Pali Rohár
2020-09-11 16:52     ` Konstantin Komarov
2020-09-21 13:36       ` Pali Rohár
2020-09-22 10:26         ` Aurélien Aptel
2020-09-25 16:39         ` Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 05/10] fs/ntfs3: Add attrib operations Konstantin Komarov
2020-08-28 16:14   ` Mark Harmstone
2020-08-28 14:39 ` [PATCH v3 06/10] fs/ntfs3: Add compression Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 07/10] fs/ntfs3: Add NTFS journal Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 08/10] fs/ntfs3: Add Kconfig, Makefile and doc Konstantin Komarov
2020-08-28 14:39 ` [PATCH v3 09/10] fs/ntfs3: Add NTFS3 in fs/Kconfig and fs/Makefile Konstantin Komarov
2020-09-01  0:37   ` kernel test robot
2020-09-01  4:45   ` kernel test robot
2020-08-28 14:39 ` [PATCH v3 10/10] fs/ntfs3: Add MAINTAINERS Konstantin Komarov
2020-08-29 11:31 ` [PATCH v3 00/10] NTFS read-write driver GPL implementation by Paragon Software Nikolay Borisov
2020-09-04 12:55   ` Konstantin Komarov

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