static void sdcardfs_d_release(struct dentry *dentry)
{
/* release and reset the lower paths */
if(has_graft_path(dentry)) {
sdcardfs_put_reset_orig_path(dentry);
}
sdcardfs_put_reset_lower_path(dentry);
free_dentry_private_data(dentry);
return;
}
/*
* Main driver function for sdcardfs's lookup.
*
* Returns: NULL (ok), ERR_PTR if an error occurred.
* Fills in lower_parent_path with <dentry,mnt> on success.
*/
static struct dentry *__sdcardfs_lookup(struct dentry *dentry,
struct nameidata *nd, struct path *lower_parent_path)
{
int err = 0;
struct vfsmount *lower_dir_mnt;
struct dentry *lower_dir_dentry = NULL;
struct dentry *lower_dentry;
const char *name;
struct path lower_path;
struct qstr this;
struct sdcardfs_sb_info *sbi;
struct nameidata lower_nd;
sbi = SDCARDFS_SB(dentry->d_sb);
/* must initialize dentry operations */
d_set_d_op(dentry, &sdcardfs_ci_dops);
if (IS_ROOT(dentry))
goto out;
name = dentry->d_name.name;
/* now start the actual lookup procedure */
lower_dir_dentry = lower_parent_path->dentry;
lower_dir_mnt = lower_parent_path->mnt;
/* Use vfs_path_lookup to check if the dentry exists or not */
if (sbi->options.lower_fs == LOWER_FS_EXT4) {
err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name,
LOOKUP_CASE_INSENSITIVE, &lower_nd);
} else if (sbi->options.lower_fs == LOWER_FS_FAT) {
err = vfs_path_lookup(lower_dir_dentry, lower_dir_mnt, name, 0,
&lower_nd);
}
lower_path = lower_nd.path;
/* no error: handle positive dentries */
if (!err) {
/* check if the dentry is an obb dentry
* if true, the lower_inode must be replaced with
* the inode of the graft path */
if(need_graft_path(dentry)) {
/* setup_obb_dentry()
* The lower_path will be stored to the dentry's orig_path
* and the base obbpath will be copyed to the lower_path variable.
* if an error returned, there's no change in the lower_path
* returns: -ERRNO if error (0: no error) */
err = setup_obb_dentry(dentry, &lower_path);
if(err) {
/* if the sbi->obbpath is not available, we can optionally
* setup the lower_path with its orig_path.
* but, the current implementation just returns an error
* because the sdcard daemon also regards this case as
* a lookup fail. */
printk(KERN_INFO "sdcardfs: base obbpath is not available\n");
sdcardfs_put_reset_orig_path(dentry);
goto out;
}
}
sdcardfs_set_lower_path(dentry, &lower_path);
err = sdcardfs_interpose(dentry, dentry->d_sb, &lower_path);
if (err) /* path_put underlying path on error */
sdcardfs_put_reset_lower_path(dentry);
goto out;
}
/*
* We don't consider ENOENT an error, and we want to return a
* negative dentry.
*/
if (err && err != -ENOENT)
goto out;
/* instatiate a new negative dentry */
this.name = name;
this.len = strlen(name);
this.hash = full_name_hash(this.name, this.len);
lower_dentry = d_lookup(lower_dir_dentry, &this);
if (lower_dentry)
goto setup_lower;
lower_dentry = d_alloc(lower_dir_dentry, &this);
if (!lower_dentry) {
err = -ENOMEM;
goto out;
}
d_add(lower_dentry, NULL); /* instantiate and hash */
setup_lower:
lower_path.dentry = lower_dentry;
lower_path.mnt = mntget(lower_dir_mnt);
sdcardfs_set_lower_path(dentry, &lower_path);
/*
* If the intent is to create a file, then don't return an error, so
* the VFS will continue the process of making this negative dentry
* into a positive one.
*/
if (nd) {
if (nd->flags & (LOOKUP_CREATE|LOOKUP_RENAME_TARGET))
err = 0;
} else
err = 0;
out:
return ERR_PTR(err);
}
