Commit de82e210 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Zheng Zengkai
Browse files

configfs: fold configfs_attach_attr into configfs_lookup 

mainline inclusion
from mainline-v5.15-rc1
commit d07f132a
category: bugfix
bugzilla: 187567, https://gitee.com/openeuler/kernel/issues/I5PK1G
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/fs/configfs/dir.c?h=v6.0-rc3&id=d07f132a225c013e59aa77f514ad9211ecab82ee



--------------------------------

This makes it more clear what gets added to the dcache and prepares
for an additional locking fix.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarZhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: default avatarZhang Yi <yi.zhang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 5d28738d

fs/configfs/dir.c

+24 −49
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ static void configfs_d_iput(struct dentry * dentry, 
		/*

		 * Set sd->s_dentry to null only when this dentry is the one

		 * that is going to be killed.  Otherwise configfs_d_iput may

		 * run just after configfs_attach_attr and set sd->s_dentry to

		 * run just after configfs_lookup and set sd->s_dentry to

		 * NULL even it's still in use.

		 */

		if (sd->s_dentry == dentry)
@@ -426,44 +426,13 @@ static void configfs_remove_dir(struct config_item * item) 
	dput(dentry);

}





/* attaches attribute's configfs_dirent to the dentry corresponding to the

 * attribute file

 */

static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)

{

	struct configfs_attribute * attr = sd->s_element;

	struct inode *inode;



	spin_lock(&configfs_dirent_lock);

	dentry->d_fsdata = configfs_get(sd);

	sd->s_dentry = dentry;

	spin_unlock(&configfs_dirent_lock);



	inode = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG);

	if (IS_ERR(inode)) {

		configfs_put(sd);

		return PTR_ERR(inode);

	}

	if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) {

		inode->i_size = 0;

		inode->i_fop = &configfs_bin_file_operations;

	} else {

		inode->i_size = PAGE_SIZE;

		inode->i_fop = &configfs_file_operations;

	}

	d_add(dentry, inode);

	return 0;

}



static struct dentry * configfs_lookup(struct inode *dir,

				       struct dentry *dentry,

				       unsigned int flags)

{

	struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;

	struct configfs_dirent * sd;

	int found = 0;

	int err;

	struct inode *inode = NULL;



	if (dentry->d_name.len > NAME_MAX)

		return ERR_PTR(-ENAMETOOLONG);
@@ -480,30 +449,36 @@ static struct dentry * configfs_lookup(struct inode *dir, 
		return ERR_PTR(-ENOENT);



	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {

		if (sd->s_type & CONFIGFS_NOT_PINNED) {

			const unsigned char * name = configfs_get_name(sd);

		if ((sd->s_type & CONFIGFS_NOT_PINNED) &&

		    !strcmp(configfs_get_name(sd), dentry->d_name.name)) {

			struct configfs_attribute *attr = sd->s_element;

			umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG;



			if (strcmp(name, dentry->d_name.name))

				continue;

			spin_lock(&configfs_dirent_lock);

			dentry->d_fsdata = configfs_get(sd);

			sd->s_dentry = dentry;

			spin_unlock(&configfs_dirent_lock);



			found = 1;

			err = configfs_attach_attr(sd, dentry);

			inode = configfs_create(dentry, mode);

			if (IS_ERR(inode)) {

				configfs_put(sd);

				return ERR_CAST(inode);

			}

			if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) {

				inode->i_size = 0;

				inode->i_fop = &configfs_bin_file_operations;

			} else {

				inode->i_size = PAGE_SIZE;

				inode->i_fop = &configfs_file_operations;

			}

			break;

		}

	}



	if (!found) {

		/*

		 * If it doesn't exist and it isn't a NOT_PINNED item,

		 * it must be negative.

		 */

		d_add(dentry, NULL);

	d_add(dentry, inode);

	return NULL;

}



	return ERR_PTR(err);

}



/*

 * Only subdirectories count here.  Files (CONFIGFS_NOT_PINNED) are

 * attributes and are removed by rmdir().  We recurse, setting