/*
* This function replicates the directory structure up-to given dentry
* in the bindex branch.
*/
struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
const char *name, int bindex)
{
int err;
struct dentry *child_dentry;
struct dentry *parent_dentry;
struct dentry *lower_parent_dentry = NULL;
struct dentry *lower_dentry = NULL;
const char *childname;
unsigned int childnamelen;
int nr_dentry;
int count = 0;
int old_bstart;
int old_bend;
struct dentry **path = NULL;
struct super_block *sb;
verify_locked(dentry);
err = is_robranch_super(dir->i_sb, bindex);
if (err) {
lower_dentry = ERR_PTR(err);
goto out;
}
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
lower_dentry = ERR_PTR(-ENOMEM);
/* There is no sense allocating any less than the minimum. */
nr_dentry = 1;
path = kmalloc(nr_dentry * sizeof(struct dentry *), GFP_KERNEL);
if (unlikely(!path))
goto out;
/* assume the negative dentry of unionfs as the parent dentry */
parent_dentry = dentry;
/*
* This loop finds the first parent that exists in the given branch.
* We start building the directory structure from there. At the end
* of the loop, the following should hold:
* - child_dentry is the first nonexistent child
* - parent_dentry is the first existent parent
* - path[0] is the = deepest child
* - path[count] is the first child to create
*/
do {
child_dentry = parent_dentry;
/* find the parent directory dentry in unionfs */
parent_dentry = dget_parent(child_dentry);
/* find out the lower_parent_dentry in the given branch */
lower_parent_dentry =
unionfs_lower_dentry_idx(parent_dentry, bindex);
/* grow path table */
if (count == nr_dentry) {
void *p;
nr_dentry *= 2;
p = krealloc(path, nr_dentry * sizeof(struct dentry *),
GFP_KERNEL);
if (unlikely(!p)) {
lower_dentry = ERR_PTR(-ENOMEM);
goto out;
}
path = p;
}
/* store the child dentry */
path[count++] = child_dentry;
} while (!lower_parent_dentry);
count--;
sb = dentry->d_sb;
/*
* This code goes between the begin/end labels and basically
* emulates a while(child_dentry != dentry), only cleaner and
* shorter than what would be a much longer while loop.
*/
begin:
/* get lower parent dir in the current branch */
lower_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
dput(parent_dentry);
/* init the values to lookup */
childname = child_dentry->d_name.name;
childnamelen = child_dentry->d_name.len;
if (child_dentry != dentry) {
/* lookup child in the underlying file system */
lower_dentry = lookup_one_len(childname, lower_parent_dentry,
childnamelen);
if (IS_ERR(lower_dentry))
goto out;
} else {
/*
* Is the name a whiteout of the child name ? lookup the
* whiteout child in the underlying file system
*/
lower_dentry = lookup_one_len(name, lower_parent_dentry,
strlen(name));
if (IS_ERR(lower_dentry))
goto out;
/* Replace the current dentry (if any) with the new one */
dput(unionfs_lower_dentry_idx(dentry, bindex));
unionfs_set_lower_dentry_idx(dentry, bindex,
lower_dentry);
__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
goto out;
}
if (lower_dentry->d_inode) {
/*
* since this already exists we dput to avoid
* multiple references on the same dentry
*/
dput(lower_dentry);
} else {
struct sioq_args args;
/* it's a negative dentry, create a new dir */
lower_parent_dentry = lock_parent(lower_dentry);
args.mkdir.parent = lower_parent_dentry->d_inode;
args.mkdir.dentry = lower_dentry;
args.mkdir.mode = child_dentry->d_inode->i_mode;
run_sioq(__unionfs_mkdir, &args);
err = args.err;
if (!err)
err = copyup_permissions(dir->i_sb, child_dentry,
lower_dentry);
unlock_dir(lower_parent_dentry);
if (err) {
dput(lower_dentry);
lower_dentry = ERR_PTR(err);
goto out;
}
}
__set_inode(child_dentry, lower_dentry, bindex);
__set_dentry(child_dentry, lower_dentry, bindex);
/*
* update times of this dentry, but also the parent, because if
* we changed, the parent may have changed too.
*/
fsstack_copy_attr_times(parent_dentry->d_inode,
lower_parent_dentry->d_inode);
unionfs_copy_attr_times(child_dentry->d_inode);
parent_dentry = child_dentry;
child_dentry = path[--count];
goto begin;
out:
/* cleanup any leftover locks from the do/while loop above */
if (IS_ERR(lower_dentry))
while (count)
dput(path[count--]);
kfree(path);
return lower_dentry;
}
/* This function replicates the directory structure upto given dentry
* in the bindex branch.
*/
static struct dentry *create_parents_named(struct inode *dir,
struct dentry *dentry,
const char *name, int bindex)
{
int err;
struct dentry *child_dentry;
struct dentry *parent_dentry;
struct dentry *hidden_parent_dentry = NULL;
struct dentry *hidden_dentry = NULL;
const char *childname;
unsigned int childnamelen;
int old_kmalloc_size;
int kmalloc_size;
int num_dentry;
int count;
int old_bstart;
int old_bend;
struct dentry **path = NULL;
struct dentry **tmp_path;
struct super_block *sb;
verify_locked(dentry);
/* There is no sense allocating any less than the minimum. */
kmalloc_size = malloc_sizes[0].cs_size;
num_dentry = kmalloc_size / sizeof(struct dentry *);
if ((err = is_robranch_super(dir->i_sb, bindex))) {
hidden_dentry = ERR_PTR(err);
goto out;
}
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
hidden_dentry = ERR_PTR(-ENOMEM);
path = kzalloc(kmalloc_size, GFP_KERNEL);
if (!path)
goto out;
/* assume the negative dentry of unionfs as the parent dentry */
parent_dentry = dentry;
count = 0;
/* This loop finds the first parent that exists in the given branch.
* We start building the directory structure from there. At the end
* of the loop, the following should hold:
* - child_dentry is the first nonexistent child
* - parent_dentry is the first existent parent
* - path[0] is the = deepest child
* - path[count] is the first child to create
*/
do {
child_dentry = parent_dentry;
/* find the parent directory dentry in unionfs */
parent_dentry = child_dentry->d_parent;
unionfs_lock_dentry(parent_dentry);
/* find out the hidden_parent_dentry in the given branch */
hidden_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
/* store the child dentry */
path[count++] = child_dentry;
/* grow path table */
if (count == num_dentry) {
old_kmalloc_size = kmalloc_size;
kmalloc_size *= 2;
num_dentry = kmalloc_size / sizeof(struct dentry *);
tmp_path = kzalloc(kmalloc_size, GFP_KERNEL);
if (!tmp_path) {
hidden_dentry = ERR_PTR(-ENOMEM);
goto out;
}
memcpy(tmp_path, path, old_kmalloc_size);
kfree(path);
path = tmp_path;
tmp_path = NULL;
}
} while (!hidden_parent_dentry);
count--;
sb = dentry->d_sb;
/* This is basically while(child_dentry != dentry). This loop is
* horrible to follow and should be replaced with cleaner code.
*/
while (1) {
/* get hidden parent dir in the current branch */
hidden_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
unionfs_unlock_dentry(parent_dentry);
/* init the values to lookup */
childname = child_dentry->d_name.name;
childnamelen = child_dentry->d_name.len;
if (child_dentry != dentry) {
/* lookup child in the underlying file system */
hidden_dentry =
lookup_one_len(childname, hidden_parent_dentry,
childnamelen);
if (IS_ERR(hidden_dentry))
goto out;
} else {
/* is the name a whiteout of the childname ?
* lookup the whiteout child in the underlying file system
*/
hidden_dentry =
lookup_one_len(name, hidden_parent_dentry,
strlen(name));
if (IS_ERR(hidden_dentry))
goto out;
/* Replace the current dentry (if any) with the new one. */
dput(unionfs_lower_dentry_idx(dentry, bindex));
unionfs_set_lower_dentry_idx(dentry, bindex, hidden_dentry);
__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
break;
}
if (hidden_dentry->d_inode) {
/* since this already exists we dput to avoid
* multiple references on the same dentry
*/
dput(hidden_dentry);
} else {
struct sioq_args args;
/* its a negative dentry, create a new dir */
hidden_parent_dentry = lock_parent(hidden_dentry);
args.mkdir.parent = hidden_parent_dentry->d_inode;
args.mkdir.dentry = hidden_dentry;
args.mkdir.mode = child_dentry->d_inode->i_mode;
run_sioq(__unionfs_mkdir, &args);
err = args.err;
if (!err)
err = copyup_permissions(dir->i_sb,
child_dentry, hidden_dentry);
unlock_dir(hidden_parent_dentry);
if (err) {
dput(hidden_dentry);
hidden_dentry = ERR_PTR(err);
goto out;
}
}
__set_inode(child_dentry, hidden_dentry, bindex);
__set_dentry(child_dentry, hidden_dentry, bindex);
parent_dentry = child_dentry;
child_dentry = path[--count];
}
out:
kfree(path);
return hidden_dentry;
}