Commit 1a0a397e authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Al Viro
Browse files

dcache: d_obtain_alias callers don't all want DISCONNECTED 



There are a few d_obtain_alias callers that are using it to get the
root of a filesystem which may already have an alias somewhere else.

This is not the same as the filehandle-lookup case, and none of them
actually need DCACHE_DISCONNECTED set.

It isn't really a serious problem, but it would really be clearer if we
reserved DCACHE_DISCONNECTED for those cases where it's actually needed.

In the btrfs case this was causing a spurious printk from
nfsd/nfsfh.c:fh_verify when it found an unexpected DCACHE_DISCONNECTED
dentry.  Josef worked around this by unsetting DCACHE_DISCONNECTED
manually in 3a0dfa6a "Btrfs: unset DCACHE_DISCONNECTED when mounting
default subvol", and this replaces that workaround.

Cc: Josef Bacik <jbacik@fb.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent da093a9b

fs/btrfs/super.c

+1 −8
Original line number Diff line number Diff line
@@ -851,7 +851,6 @@ static struct dentry *get_default_root(struct super_block *sb, 
	struct btrfs_path *path;

	struct btrfs_key location;

	struct inode *inode;

	struct dentry *dentry;

	u64 dir_id;

	int new = 0;
@@ -922,13 +921,7 @@ setup_root: 
		return dget(sb->s_root);

	}



	dentry = d_obtain_alias(inode);

	if (!IS_ERR(dentry)) {

		spin_lock(&dentry->d_lock);

		dentry->d_flags &= ~DCACHE_DISCONNECTED;

		spin_unlock(&dentry->d_lock);

	}

	return dentry;

	return d_obtain_root(inode);

}



static int btrfs_fill_super(struct super_block *sb,

fs/ceph/super.c

+1 −1
Original line number Diff line number Diff line
@@ -755,7 +755,7 @@ static struct dentry *open_root_dentry(struct ceph_fs_client *fsc, 
				goto out;

			}

		} else {

			root = d_obtain_alias(inode);

			root = d_obtain_root(inode);

		}

		ceph_init_dentry(root);

		dout("open_root_inode success, root dentry is %p\n", root);

fs/dcache.c

+49 −20
Original line number Diff line number Diff line
@@ -1781,25 +1781,7 @@ struct dentry *d_find_any_alias(struct inode *inode) 
}

EXPORT_SYMBOL(d_find_any_alias);



/**

 * d_obtain_alias - find or allocate a dentry for a given inode

 * @inode: inode to allocate the dentry for

 *

 * Obtain a dentry for an inode resulting from NFS filehandle conversion or

 * similar open by handle operations.  The returned dentry may be anonymous,

 * or may have a full name (if the inode was already in the cache).

 *

 * When called on a directory inode, we must ensure that the inode only ever

 * has one dentry.  If a dentry is found, that is returned instead of

 * allocating a new one.

 *

 * On successful return, the reference to the inode has been transferred

 * to the dentry.  In case of an error the reference on the inode is released.

 * To make it easier to use in export operations a %NULL or IS_ERR inode may

 * be passed in and will be the error will be propagate to the return value,

 * with a %NULL @inode replaced by ERR_PTR(-ESTALE).

 */

struct dentry *d_obtain_alias(struct inode *inode)

struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)

{

	static const struct qstr anonstring = QSTR_INIT("/", 1);

	struct dentry *tmp;
@@ -1830,7 +1812,10 @@ struct dentry *d_obtain_alias(struct inode *inode) 
	}



	/* attach a disconnected dentry */

	add_flags = d_flags_for_inode(inode) | DCACHE_DISCONNECTED;

	add_flags = d_flags_for_inode(inode);



	if (disconnected)

		add_flags |= DCACHE_DISCONNECTED;



	spin_lock(&tmp->d_lock);

	tmp->d_inode = inode;
@@ -1851,8 +1836,52 @@ struct dentry *d_obtain_alias(struct inode *inode) 
	iput(inode);

	return res;

}



/**

 * d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode

 * @inode: inode to allocate the dentry for

 *

 * Obtain a dentry for an inode resulting from NFS filehandle conversion or

 * similar open by handle operations.  The returned dentry may be anonymous,

 * or may have a full name (if the inode was already in the cache).

 *

 * When called on a directory inode, we must ensure that the inode only ever

 * has one dentry.  If a dentry is found, that is returned instead of

 * allocating a new one.

 *

 * On successful return, the reference to the inode has been transferred

 * to the dentry.  In case of an error the reference on the inode is released.

 * To make it easier to use in export operations a %NULL or IS_ERR inode may

 * be passed in and the error will be propagated to the return value,

 * with a %NULL @inode replaced by ERR_PTR(-ESTALE).

 */

struct dentry *d_obtain_alias(struct inode *inode)

{

	return __d_obtain_alias(inode, 1);

}

EXPORT_SYMBOL(d_obtain_alias);



/**

 * d_obtain_root - find or allocate a dentry for a given inode

 * @inode: inode to allocate the dentry for

 *

 * Obtain an IS_ROOT dentry for the root of a filesystem.

 *

 * We must ensure that directory inodes only ever have one dentry.  If a

 * dentry is found, that is returned instead of allocating a new one.

 *

 * On successful return, the reference to the inode has been transferred

 * to the dentry.  In case of an error the reference on the inode is

 * released.  A %NULL or IS_ERR inode may be passed in and will be the

 * error will be propagate to the return value, with a %NULL @inode

 * replaced by ERR_PTR(-ESTALE).

 */

struct dentry *d_obtain_root(struct inode *inode)

{

	return __d_obtain_alias(inode, 0);

}

EXPORT_SYMBOL(d_obtain_root);



/**

 * d_add_ci - lookup or allocate new dentry with case-exact name

 * @inode:  the inode case-insensitive lookup has found

fs/nfs/getroot.c

+1 −1
Original line number Diff line number Diff line
@@ -112,7 +112,7 @@ struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh, 
	 * if the dentry tree reaches them; however if the dentry already

	 * exists, we'll pick it up at this point and use it as the root

	 */

	ret = d_obtain_alias(inode);

	ret = d_obtain_root(inode);

	if (IS_ERR(ret)) {

		dprintk("nfs_get_root: get root dentry failed\n");

		goto out;

fs/nilfs2/super.c

+1 −1
Original line number Diff line number Diff line
@@ -942,7 +942,7 @@ static int nilfs_get_root_dentry(struct super_block *sb, 
			iput(inode);

		}

	} else {

		dentry = d_obtain_alias(inode);

		dentry = d_obtain_root(inode);

		if (IS_ERR(dentry)) {

			ret = PTR_ERR(dentry);

			goto failed_dentry;

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