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Commit d0497fe3 authored by Daniel Rosenberg's avatar Daniel Rosenberg
Browse files

ANDROID: sdcardfs: use d_splice_alias 



adapted from wrapfs
commit 9671770ff8b9 ("Wrapfs: use d_splice_alias")

Refactor interpose code to allow lookup to use d_splice_alias.

Signed-off-by: default avatarErez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
Bug: 35766959
Change-Id: Icf51db8658202c48456724275b03dc77f73f585b
parent a3349124

fs/sdcardfs/lookup.c

+39 −16
Original line number Diff line number Diff line
@@ -164,27 +164,25 @@ struct inode *sdcardfs_iget(struct super_block *sb, struct inode *lower_inode, u 
}



/*

 * Connect a sdcardfs inode dentry/inode with several lower ones.  This is

 * the classic stackable file system "vnode interposition" action.

 *

 * @dentry: sdcardfs's dentry which interposes on lower one

 * @sb: sdcardfs's super_block

 * @lower_path: the lower path (caller does path_get/put)

 * Helper interpose routine, called directly by ->lookup to handle

 * spliced dentries.

 */

int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,

		     struct path *lower_path, userid_t id)

static struct dentry *__sdcardfs_interpose(struct dentry *dentry,

					 struct super_block *sb,

					 struct path *lower_path,

					 userid_t id)

{

	int err = 0;

	struct inode *inode;

	struct inode *lower_inode;

	struct super_block *lower_sb;

	struct dentry *ret_dentry;



	lower_inode = d_inode(lower_path->dentry);

	lower_sb = sdcardfs_lower_super(sb);



	/* check that the lower file system didn't cross a mount point */

	if (lower_inode->i_sb != lower_sb) {

		err = -EXDEV;

		ret_dentry = ERR_PTR(-EXDEV);

		goto out;

	}
@@ -196,14 +194,32 @@ int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb, 
	/* inherit lower inode number for sdcardfs's inode */

	inode = sdcardfs_iget(sb, lower_inode, id);

	if (IS_ERR(inode)) {

		err = PTR_ERR(inode);

		ret_dentry = ERR_CAST(inode);

		goto out;

	}



	d_add(dentry, inode);

	ret_dentry = d_splice_alias(inode, dentry);

	dentry = ret_dentry ?: dentry;

	update_derived_permission_lock(dentry);

out:

	return err;

	return ret_dentry;

}



/*

 * Connect an sdcardfs inode dentry/inode with several lower ones.  This is

 * the classic stackable file system "vnode interposition" action.

 *

 * @dentry: sdcardfs's dentry which interposes on lower one

 * @sb: sdcardfs's super_block

 * @lower_path: the lower path (caller does path_get/put)

 */

int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,

		     struct path *lower_path, userid_t id)

{

	struct dentry *ret_dentry;



	ret_dentry = __sdcardfs_interpose(dentry, sb, lower_path, id);

	return PTR_ERR(ret_dentry);

}



struct sdcardfs_name_data {
@@ -244,6 +260,7 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry, 
	const struct qstr *name;

	struct path lower_path;

	struct qstr dname;

	struct dentry *ret_dentry = NULL;

	struct sdcardfs_sb_info *sbi;



	sbi = SDCARDFS_SB(dentry->d_sb);
@@ -330,9 +347,13 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry, 
		}



		sdcardfs_set_lower_path(dentry, &lower_path);

		err = sdcardfs_interpose(dentry, dentry->d_sb, &lower_path, id);

		if (err) /* path_put underlying path on error */

		ret_dentry =

			__sdcardfs_interpose(dentry, dentry->d_sb, &lower_path, id);

		if (IS_ERR(ret_dentry)) {

			err = PTR_ERR(ret_dentry);

			 /* path_put underlying path on error */

			sdcardfs_put_reset_lower_path(dentry);

		}

		goto out;

	}
@@ -372,7 +393,9 @@ static struct dentry *__sdcardfs_lookup(struct dentry *dentry, 
		err = 0;



out:

	if (err)

		return ERR_PTR(err);

	return ret_dentry;

}



/*