int unionfs_ioctl_addbranch(struct inode *inode, unsigned int cmd,
unsigned long arg)
{
int err;
struct unionfs_addbranch_args *addargs = NULL;
struct nameidata nd;
char *path = NULL;
int gen;
int i;
int pobjects;
struct unionfs_usi_data *new_data = NULL;
struct dentry **new_udi_dentry = NULL;
struct inode **new_uii_inode = NULL;
struct dentry *root = NULL;
struct dentry *hidden_root = NULL;
print_entry_location();
err = -ENOMEM;
addargs = KMALLOC(sizeof(struct unionfs_addbranch_args), GFP_KERNEL);
if (!addargs)
goto out;
err = -EFAULT;
if (copy_from_user
(addargs, (const void __user *)arg,
sizeof(struct unionfs_addbranch_args)))
goto out;
err = -EINVAL;
if (addargs->ab_perms & ~(MAY_READ | MAY_WRITE | MAY_NFSRO))
goto out;
if (!(addargs->ab_perms & MAY_READ))
goto out;
err = -E2BIG;
if (sbend(inode->i_sb) > FD_SETSIZE)
goto out;
err = -ENOMEM;
if (!(path = getname((const char __user *)addargs->ab_path)))
goto out;
err = path_lookup(path, LOOKUP_FOLLOW, &nd);
RECORD_PATH_LOOKUP(&nd);
if (err)
goto out;
if ((err = check_branch(&nd))) {
path_release(&nd);
RECORD_PATH_RELEASE(&nd);
goto out;
}
unionfs_write_lock(inode->i_sb);
lock_dentry(inode->i_sb->s_root);
root = inode->i_sb->s_root;
for (i = dbstart(inode->i_sb->s_root); i <= dbend(inode->i_sb->s_root);
i++) {
hidden_root = dtohd_index(root, i);
if (is_branch_overlap(hidden_root, nd.dentry)) {
err = -EINVAL;
goto out;
}
}
err = -EINVAL;
if (addargs->ab_branch < 0
|| (addargs->ab_branch > (sbend(inode->i_sb) + 1)))
goto out;
if ((err = newputmap(inode->i_sb)))
goto out;
stopd(inode->i_sb)->b_end++;
dtopd(inode->i_sb->s_root)->udi_bcount++;
set_dbend(inode->i_sb->s_root, dbend(inode->i_sb->s_root) + 1);
itopd(inode->i_sb->s_root->d_inode)->b_end++;
atomic_inc(&stopd(inode->i_sb)->usi_generation);
gen = atomic_read(&stopd(inode->i_sb)->usi_generation);
pobjects = sbend(inode->i_sb) + 1;
/* Reallocate the dynamic structures. */
new_data = alloc_new_data(pobjects);
new_udi_dentry = alloc_new_dentries(pobjects);
new_uii_inode = KZALLOC(sizeof(struct inode *) * pobjects, GFP_KERNEL);
if (!new_udi_dentry || !new_uii_inode || !new_data) {
err = -ENOMEM;
goto out;
}
/* Copy the in-place values to our new structure. */
for (i = 0; i < addargs->ab_branch; i++) {
atomic_set(&(new_data[i].sbcount),
branch_count(inode->i_sb, i));
new_data[i].branchperms = branchperms(inode->i_sb, i);
new_data[i].hidden_mnt = stohiddenmnt_index(inode->i_sb, i);
new_data[i].sb = stohs_index(inode->i_sb, i);
new_udi_dentry[i] = dtohd_index(inode->i_sb->s_root, i);
new_uii_inode[i] = itohi_index(inode->i_sb->s_root->d_inode, i);
}
/* Shift the ends to the right (only handle reallocated bits). */
for (i = sbend(inode->i_sb) - 1; i >= (int)addargs->ab_branch; i--) {
int j = i + 1;
int pmindex;
atomic_set(&new_data[j].sbcount, branch_count(inode->i_sb, i));
new_data[j].branchperms = branchperms(inode->i_sb, i);
new_data[j].hidden_mnt = stohiddenmnt_index(inode->i_sb, i);
new_data[j].sb = stohs_index(inode->i_sb, i);
new_udi_dentry[j] = dtohd_index(inode->i_sb->s_root, i);
new_uii_inode[j] = itohi_index(inode->i_sb->s_root->d_inode, i);
/* Update the newest putmap, so it is correct for later. */
pmindex = stopd(inode->i_sb)->usi_lastputmap;
pmindex -= stopd(inode->i_sb)->usi_firstputmap;
stopd(inode->i_sb)->usi_putmaps[pmindex]->map[i] = j;
}
/* Now we can free the old ones. */
KFREE(dtopd(inode->i_sb->s_root)->udi_dentry);
KFREE(itopd(inode->i_sb->s_root->d_inode)->uii_inode);
KFREE(stopd(inode->i_sb)->usi_data);
/* Update the real pointers. */
dtohd_ptr(inode->i_sb->s_root) = new_udi_dentry;
itohi_ptr(inode->i_sb->s_root->d_inode) = new_uii_inode;
stopd(inode->i_sb)->usi_data = new_data;
/* Re-NULL the new ones so we don't try to free them. */
new_data = NULL;
new_udi_dentry = NULL;
new_uii_inode = NULL;
/* Put the new dentry information into it's slot. */
set_dtohd_index(inode->i_sb->s_root, addargs->ab_branch, nd.dentry);
set_itohi_index(inode->i_sb->s_root->d_inode, addargs->ab_branch,
IGRAB(nd.dentry->d_inode));
set_branchperms(inode->i_sb, addargs->ab_branch, addargs->ab_perms);
set_branch_count(inode->i_sb, addargs->ab_branch, 0);
set_stohiddenmnt_index(inode->i_sb, addargs->ab_branch, nd.mnt);
set_stohs_index(inode->i_sb, addargs->ab_branch, nd.dentry->d_sb);
atomic_set(&dtopd(inode->i_sb->s_root)->udi_generation, gen);
atomic_set(&itopd(inode->i_sb->s_root->d_inode)->uii_generation, gen);
fixputmaps(inode->i_sb);
out:
unlock_dentry(inode->i_sb->s_root);
unionfs_write_unlock(inode->i_sb);
KFREE(new_udi_dentry);
KFREE(new_uii_inode);
KFREE(new_data);
KFREE(addargs);
if (path)
putname(path);
print_exit_status(err);
return err;
}
static int parse_dirs_option(struct super_block *sb, struct unionfs_dentry_info
*hidden_root_info, char *options)
{
struct nameidata nd;
char *name;
int err = 0;
int branches = 1;
int bindex = 0;
int i = 0;
int j = 0;
struct dentry *dent1 = NULL;
struct dentry *dent2 = NULL;
if (options[0] == '\0') {
printk(KERN_WARNING "unionfs: no branches specified\n");
err = -EINVAL;
goto out;
}
/* Each colon means we have a separator, this is really just a rough
* guess, since strsep will handle empty fields for us. */
for (i = 0; options[i]; i++) {
if (options[i] == ':')
branches++;
}
/* allocate space for underlying pointers to hidden dentry */
if (!(stopd(sb)->usi_data = alloc_new_data(branches))) {
err = -ENOMEM;
goto out;
}
if (!(hidden_root_info->udi_dentry = alloc_new_dentries(branches))) {
err = -ENOMEM;
goto out;
}
/* now parsing the string b1:b2=rw:b3=ro:b4 */
branches = 0;
while ((name = strsep(&options, ":")) != NULL) {
int perms;
if (!*name)
continue;
branches++;
/* strip off =rw or =ro if it is specified. */
perms = parse_branch_mode(name);
if (!bindex && !(perms & MAY_WRITE)) {
err = -EINVAL;
goto out;
}
fist_dprint(4, "unionfs: using directory: %s (%c%c%c)\n",
name, perms & MAY_READ ? 'r' : '-',
perms & MAY_WRITE ? 'w' : '-',
perms & MAY_NFSRO ? 'n' : '-');
err = path_lookup(name, LOOKUP_FOLLOW, &nd);
RECORD_PATH_LOOKUP(&nd);
if (err) {
printk(KERN_WARNING "unionfs: error accessing "
"hidden directory '%s' (error %d)\n", name, err);
goto out;
}
if ((err = check_branch(&nd))) {
printk(KERN_WARNING "unionfs: hidden directory "
"'%s' is not a valid branch\n", name);
path_release(&nd);
RECORD_PATH_RELEASE(&nd);
goto out;
}
hidden_root_info->udi_dentry[bindex] = nd.dentry;
set_stohiddenmnt_index(sb, bindex, nd.mnt);
set_branchperms(sb, bindex, perms);
set_branch_count(sb, bindex, 0);
if (hidden_root_info->udi_bstart < 0)
hidden_root_info->udi_bstart = bindex;
hidden_root_info->udi_bend = bindex;
bindex++;
}
if (branches == 0) {
printk(KERN_WARNING "unionfs: no branches specified\n");
err = -EINVAL;
goto out;
}
BUG_ON(branches != (hidden_root_info->udi_bend + 1));
/* ensure that no overlaps exist in the branches */
for (i = 0; i < branches; i++) {
for (j = i + 1; j < branches; j++) {
dent1 = hidden_root_info->udi_dentry[i];
dent2 = hidden_root_info->udi_dentry[j];
if (is_branch_overlap(dent1, dent2)) {
goto out_overlap;
}
}
}
out_overlap:
if (i != branches) {
printk(KERN_WARNING "unionfs: branches %d and %d overlap\n", i,
j);
err = -EINVAL;
goto out;
}
out:
if (err) {
for (i = 0; i < branches; i++) {
if (hidden_root_info->udi_dentry[i])
DPUT(hidden_root_info->udi_dentry[i]);
}
KFREE(hidden_root_info->udi_dentry);
KFREE(stopd(sb)->usi_data);
/* MUST clear the pointers to prevent potential double free if
* the caller dies later on
*/
hidden_root_info->udi_dentry = NULL;
stopd(sb)->usi_data = NULL;
}
return err;
}
