void unionfs_reinterpose(struct dentry *dentry)
{
struct dentry *hidden_dentry;
struct inode *inode;
int bindex, bstart, bend;
print_entry_location();
verify_locked(dentry);
fist_print_dentry("IN: unionfs_reinterpose: ", dentry);
/* This is pre-allocated inode */
inode = dentry->d_inode;
bstart = dbstart(dentry);
bend = dbend(dentry);
for (bindex = bstart; bindex <= bend; bindex++) {
hidden_dentry = dtohd_index(dentry, bindex);
if (!hidden_dentry)
continue;
if (!hidden_dentry->d_inode)
continue;
if (itohi_index(inode, bindex))
continue;
set_itohi_index(inode, bindex, IGRAB(hidden_dentry->d_inode));
}
ibstart(inode) = dbstart(dentry);
ibend(inode) = dbend(dentry);
fist_print_dentry("OUT: unionfs_reinterpose: ", dentry);
fist_print_inode("OUT: unionfs_reinterpose: ", inode);
print_exit_location();
}
static int unionfs_permission(struct inode *inode, int mask,
struct nameidata *nd)
{
struct inode *hidden_inode = NULL;
int err = 0;
int bindex, bstart, bend;
const int is_file = !S_ISDIR(inode->i_mode);
const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ);
print_entry_location();
bstart = ibstart(inode);
bend = ibend(inode);
fist_print_inode("IN unionfs_permission", inode);
for (bindex = bstart; bindex <= bend; bindex++) {
hidden_inode = itohi_index(inode, bindex);
if (!hidden_inode)
continue;
/* check the condition for D-F-D underlying files/directories,
* we dont have to check for files, if we are checking for
* directories.
*/
if (!is_file && !S_ISDIR(hidden_inode->i_mode))
continue;
/* We use our own special version of permission, such that
* only the first branch returns -EROFS. */
err = inode_permission(hidden_inode, mask, nd, bindex);
/* The permissions are an intersection of the overall directory
* permissions, so we fail if one fails. */
if (err)
goto out;
/* only the leftmost file matters. */
if (is_file || write_mask) {
if (is_file && write_mask) {
err = get_write_access(hidden_inode);
if (!err)
put_write_access(hidden_inode);
}
break;
}
}
out:
print_exit_status(err);
return err;
}
/* This must be called with the super block already locked. */
int unionfs_ioctl_delbranch(struct super_block *sb, unsigned long arg)
{
struct dentry *hidden_dentry;
struct inode *hidden_inode;
struct super_block *hidden_sb;
struct vfsmount *hidden_mnt;
struct dentry *root_dentry;
struct inode *root_inode;
int err = 0;
int pmindex, i, gen;
print_entry("branch = %lu ", arg);
lock_dentry(sb->s_root);
err = -EBUSY;
if (sbmax(sb) == 1)
goto out;
err = -EINVAL;
if (arg < 0 || arg > stopd(sb)->b_end)
goto out;
err = -EBUSY;
if (branch_count(sb, arg))
goto out;
if ((err = newputmap(sb)))
goto out;
pmindex = stopd(sb)->usi_lastputmap;
pmindex -= stopd(sb)->usi_firstputmap;
atomic_inc(&stopd(sb)->usi_generation);
gen = atomic_read(&stopd(sb)->usi_generation);
root_dentry = sb->s_root;
root_inode = sb->s_root->d_inode;
hidden_dentry = dtohd_index(root_dentry, arg);
hidden_mnt = stohiddenmnt_index(sb, arg);
hidden_inode = itohi_index(root_inode, arg);
hidden_sb = stohs_index(sb, arg);
DPUT(hidden_dentry);
iput(hidden_inode);
mntput(hidden_mnt);
for (i = arg; i <= (sbend(sb) - 1); i++) {
set_branch_count(sb, i, branch_count(sb, i + 1));
set_stohiddenmnt_index(sb, i, stohiddenmnt_index(sb, i + 1));
set_stohs_index(sb, i, stohs_index(sb, i + 1));
set_branchperms(sb, i, branchperms(sb, i + 1));
set_dtohd_index(root_dentry, i,
dtohd_index(root_dentry, i + 1));
set_itohi_index(root_inode, i, itohi_index(root_inode, i + 1));
stopd(sb)->usi_putmaps[pmindex]->map[i + 1] = i;
}
set_dtohd_index(root_dentry, sbend(sb), NULL);
set_itohi_index(root_inode, sbend(sb), NULL);
set_stohiddenmnt_index(sb, sbend(sb), NULL);
set_stohs_index(sb, sbend(sb), NULL);
stopd(sb)->b_end--;
set_dbend(root_dentry, dbend(root_dentry) - 1);
dtopd(root_dentry)->udi_bcount--;
itopd(root_inode)->b_end--;
atomic_set(&dtopd(root_dentry)->udi_generation, gen);
atomic_set(&itopd(root_inode)->uii_generation, gen);
fixputmaps(sb);
/* This doesn't open a file, so we might have to free the map here. */
if (atomic_read(&stopd(sb)->usi_putmaps[pmindex]->count) == 0) {
KFREE(stopd(sb)->usi_putmaps[pmindex]);
stopd(sb)->usi_putmaps[pmindex] = NULL;
}
out:
unlock_dentry(sb->s_root);
print_exit_status(err);
return err;
}
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 count;
int pobjects;
struct vfsmount **new_hidden_mnt = NULL;
struct inode **new_uii_inode = NULL;
struct dentry **new_udi_dentry = NULL;
struct super_block **new_usi_sb = NULL;
int *new_branchperms = NULL;
atomic_t *new_counts = NULL;
print_entry_location();
err = -ENOMEM;
addargs = KMALLOC(sizeof(struct unionfs_addbranch_args), GFP_UNIONFS);
if (!addargs)
goto out;
err = -EFAULT;
if (copy_from_user
(addargs, (void *)arg, sizeof(struct unionfs_addbranch_args)))
goto out;
err = -EINVAL;
if (addargs->ab_perms & ~(MAY_READ | MAY_WRITE))
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(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);
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) - UNIONFS_INLINE_OBJECTS;
if (pobjects > 0) {
/* Reallocate the dynamic structures. */
new_hidden_mnt =
KMALLOC(sizeof(struct vfsmount *) * pobjects, GFP_UNIONFS);
new_udi_dentry =
KMALLOC(sizeof(struct dentry *) * pobjects, GFP_UNIONFS);
new_uii_inode =
KMALLOC(sizeof(struct inode *) * pobjects, GFP_UNIONFS);
new_usi_sb =
KMALLOC(sizeof(struct super_block *) * pobjects,
GFP_UNIONFS);
new_counts = KMALLOC(sizeof(atomic_t) * pobjects, GFP_UNIONFS);
new_branchperms = KMALLOC(sizeof(int) * pobjects, GFP_UNIONFS);
if (!new_hidden_mnt || !new_udi_dentry || !new_uii_inode
|| !new_counts || !new_usi_sb || !new_branchperms) {
err = -ENOMEM;
goto out;
}
memset(new_hidden_mnt, 0, sizeof(struct vfsmount *) * pobjects);
memset(new_udi_dentry, 0, sizeof(struct dentry *) * pobjects);
memset(new_uii_inode, 0, sizeof(struct inode *) * pobjects);
memset(new_usi_sb, 0, sizeof(struct super_block *) * pobjects);
memset(new_branchperms, 0, sizeof(int) * pobjects);
}
/* Copy the in-place values to our new structure. */
for (i = UNIONFS_INLINE_OBJECTS; i < addargs->ab_branch; i++) {
int j = i - UNIONFS_INLINE_OBJECTS;
count = branch_count(inode->i_sb, i);
atomic_set(&(new_counts[j]), count);
new_branchperms[j] = branchperms(inode->i_sb, i);
new_hidden_mnt[j] = stohiddenmnt_index(inode->i_sb, i);
new_usi_sb[j] = 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);
}
/* 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 perms;
struct vfsmount *hm;
struct super_block *hs;
struct dentry *hd;
struct inode *hi;
int pmindex;
count = branch_count(inode->i_sb, i);
perms = branchperms(inode->i_sb, i);
hm = stohiddenmnt_index(inode->i_sb, i);
hs = stohs_index(inode->i_sb, i);
hd = dtohd_index(inode->i_sb->s_root, i);
hi = 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;
if (j >= UNIONFS_INLINE_OBJECTS) {
j -= UNIONFS_INLINE_OBJECTS;
atomic_set(&(new_counts[j]), count);
new_branchperms[j] = perms;
new_hidden_mnt[j] = hm;
new_usi_sb[j] = hs;
new_udi_dentry[j] = hd;
new_uii_inode[j] = hi;
} else {
set_branch_count(inode->i_sb, j, count);
set_branchperms(inode->i_sb, j, perms);
set_stohiddenmnt_index(inode->i_sb, j, hm);
set_stohs_index(inode->i_sb, j, hs);
set_dtohd_index(inode->i_sb->s_root, j, hd);
set_itohi_index(inode->i_sb->s_root->d_inode, j, hi);
}
}
/* Now we can free the old ones. */
KFREE(dtopd(inode->i_sb->s_root)->udi_dentry_p);
KFREE(itopd(inode->i_sb->s_root->d_inode)->uii_inode_p);
KFREE(stopd(inode->i_sb)->usi_hidden_mnt_p);
KFREE(stopd(inode->i_sb)->usi_sb_p);
KFREE(stopd(inode->i_sb)->usi_sbcount_p);
KFREE(stopd(inode->i_sb)->usi_branchperms_p);
/* 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;
stohiddenmnt_ptr(inode->i_sb) = new_hidden_mnt;
stohs_ptr(inode->i_sb) = new_usi_sb;
stopd(inode->i_sb)->usi_sbcount_p = new_counts;
stopd(inode->i_sb)->usi_branchperms_p = new_branchperms;
/* Re-NULL the new ones so we don't try to free them. */
new_hidden_mnt = NULL;
new_udi_dentry = NULL;
new_usi_sb = NULL;
new_uii_inode = NULL;
new_counts = NULL;
new_branchperms = 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_hidden_mnt);
KFREE(new_udi_dentry);
KFREE(new_uii_inode);
KFREE(new_usi_sb);
KFREE(new_counts);
KFREE(new_branchperms);
KFREE(addargs);
if (path)
putname(path);
print_exit_status(err);
return err;
}
/*
* THIS IS A BOOLEAN FUNCTION: returns 1 if valid, 0 otherwise.
*/
int unionfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
{
int valid = 1; /* default is valid (1); invalid is 0. */
struct dentry *hidden_dentry;
int bindex, bstart, bend;
int sbgen, dgen;
int positive = 0;
int locked = 0;
int restart = 0;
int interpose_flag;
print_util_entry_location();
restart:
verify_locked(dentry);
/* if the dentry is unhashed, do NOT revalidate */
if (d_deleted(dentry)) {
fist_dprint(6, "unhashed dentry being revalidated: %*s\n",
dentry->d_name.len, dentry->d_name.name);
goto out;
}
BUG_ON(dbstart(dentry) == -1);
if (dentry->d_inode)
positive = 1;
dgen = atomic_read(&dtopd(dentry)->udi_generation);
sbgen = atomic_read(&stopd(dentry->d_sb)->usi_generation);
/* If we are working on an unconnected dentry, then there is no
* revalidation to be done, because this file does not exist within the
* namespace, and Unionfs operates on the namespace, not data.
*/
if (sbgen != dgen) {
struct dentry *result;
int pdgen;
unionfs_read_lock(dentry->d_sb);
locked = 1;
/* The root entry should always be valid */
BUG_ON(IS_ROOT(dentry));
/* We can't work correctly if our parent isn't valid. */
pdgen = atomic_read(&dtopd(dentry->d_parent)->udi_generation);
if (!restart && (pdgen != sbgen)) {
unionfs_read_unlock(dentry->d_sb);
locked = 0;
/* We must be locked before our parent. */
if (!
(dentry->d_parent->d_op->
d_revalidate(dentry->d_parent, nd))) {
valid = 0;
goto out;
}
restart = 1;
goto restart;
}
BUG_ON(pdgen != sbgen);
/* Free the pointers for our inodes and this dentry. */
bstart = dbstart(dentry);
bend = dbend(dentry);
if (bstart >= 0) {
struct dentry *hidden_dentry;
for (bindex = bstart; bindex <= bend; bindex++) {
hidden_dentry =
dtohd_index_nocheck(dentry, bindex);
if (!hidden_dentry)
continue;
DPUT(hidden_dentry);
}
}
set_dbstart(dentry, -1);
set_dbend(dentry, -1);
interpose_flag = INTERPOSE_REVAL_NEG;
if (positive) {
interpose_flag = INTERPOSE_REVAL;
down(&dentry->d_inode->i_sem);
bstart = ibstart(dentry->d_inode);
bend = ibend(dentry->d_inode);
if (bstart >= 0) {
struct inode *hidden_inode;
for (bindex = bstart; bindex <= bend; bindex++) {
hidden_inode =
itohi_index(dentry->d_inode,
bindex);
if (!hidden_inode)
continue;
IPUT(hidden_inode);
}
}
KFREE(itohi_ptr(dentry->d_inode));
itohi_ptr(dentry->d_inode) = NULL;
ibstart(dentry->d_inode) = -1;
ibend(dentry->d_inode) = -1;
up(&dentry->d_inode->i_sem);
}
result = unionfs_lookup_backend(dentry, interpose_flag);
if (result) {
if (IS_ERR(result)) {
valid = 0;
goto out;
}
/* current unionfs_lookup_backend() doesn't return
a valid dentry */
DPUT(dentry);
dentry = result;
}
if (positive && itopd(dentry->d_inode)->uii_stale) {
make_stale_inode(dentry->d_inode);
d_drop(dentry);
valid = 0;
goto out;
}
goto out;
}
/* The revalidation must occur across all branches */
bstart = dbstart(dentry);
bend = dbend(dentry);
BUG_ON(bstart == -1);
for (bindex = bstart; bindex <= bend; bindex++) {
hidden_dentry = dtohd_index(dentry, bindex);
if (!hidden_dentry || !hidden_dentry->d_op
|| !hidden_dentry->d_op->d_revalidate)
continue;
if (!hidden_dentry->d_op->d_revalidate(hidden_dentry, nd))
valid = 0;
}
if (!dentry->d_inode)
valid = 0;
if (valid)
fist_copy_attr_all(dentry->d_inode, itohi(dentry->d_inode));
out:
if (locked)
unionfs_read_unlock(dentry->d_sb);
fist_print_dentry("revalidate out", dentry);
print_util_exit_status(valid);
return valid;
}
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;
}
