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;
}
int copyup_named_dentry(struct inode *dir, struct dentry *dentry,
int bstart, int new_bindex, char *name,
int namelen, struct file **copyup_file, int len)
{
struct dentry *new_hidden_dentry;
struct dentry *old_hidden_dentry = NULL;
struct super_block *sb;
struct file *input_file = NULL;
struct file *output_file = NULL;
ssize_t read_bytes, write_bytes;
mm_segment_t old_fs;
int err = 0;
char *buf;
int old_bindex;
int got_branch_input = -1;
int got_branch_output = -1;
int old_bstart;
int old_bend;
int size = len;
struct dentry *new_hidden_parent_dentry;
mm_segment_t oldfs;
char *symbuf = NULL;
uid_t saved_uid = current->fsuid;
gid_t saved_gid = current->fsgid;
print_entry_location();
verify_locked(dentry);
fist_print_dentry("IN: copyup_named_dentry", dentry);
old_bindex = bstart;
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
ASSERT(new_bindex >= 0);
ASSERT(new_bindex < old_bindex);
PASSERT(dir);
PASSERT(dentry);
sb = dir->i_sb;
if ((err = is_robranch_super(sb, new_bindex)))
goto out;
/* Create the directory structure above this dentry. */
new_hidden_dentry = create_parents_named(dir, dentry, name, new_bindex);
PASSERT(new_hidden_dentry);
if (IS_ERR(new_hidden_dentry)) {
err = PTR_ERR(new_hidden_dentry);
goto out;
}
fist_print_generic_dentry("Copyup Object", new_hidden_dentry);
/* Now we actually create the object. */
old_hidden_dentry = dtohd_index(dentry, old_bindex);
PASSERT(old_hidden_dentry);
PASSERT(old_hidden_dentry->d_inode);
DGET(old_hidden_dentry);
/* For symlinks, we must read the link before we lock the directory. */
if (S_ISLNK(old_hidden_dentry->d_inode->i_mode)) {
PASSERT(old_hidden_dentry->d_inode->i_op);
PASSERT(old_hidden_dentry->d_inode->i_op->readlink);
symbuf = KMALLOC(PATH_MAX, GFP_UNIONFS);
if (!symbuf) {
err = -ENOMEM;
goto copyup_readlink_err;
}
oldfs = get_fs();
set_fs(KERNEL_DS);
err =
old_hidden_dentry->d_inode->i_op->
readlink(old_hidden_dentry, symbuf, PATH_MAX);
set_fs(oldfs);
if (err < 0)
goto copyup_readlink_err;
symbuf[err] = '\0';
}
/* Now we lock the parent, and create the object in the new branch. */
new_hidden_parent_dentry = lock_parent(new_hidden_dentry);
current->fsuid = new_hidden_parent_dentry->d_inode->i_uid;
current->fsgid = new_hidden_parent_dentry->d_inode->i_gid;
if (S_ISDIR(old_hidden_dentry->d_inode->i_mode)) {
err = vfs_mkdir(new_hidden_parent_dentry->d_inode,
new_hidden_dentry, S_IRWXU);
} else if (S_ISLNK(old_hidden_dentry->d_inode->i_mode)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
err = vfs_symlink(new_hidden_parent_dentry->d_inode,
new_hidden_dentry, symbuf);
#else
err = vfs_symlink(new_hidden_parent_dentry->d_inode,
new_hidden_dentry, symbuf, S_IRWXU);
#endif
} else if (S_ISBLK(old_hidden_dentry->d_inode->i_mode)
|| S_ISCHR(old_hidden_dentry->d_inode->i_mode)
|| S_ISFIFO(old_hidden_dentry->d_inode->i_mode)
|| S_ISSOCK(old_hidden_dentry->d_inode->i_mode)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
err = vfs_mknod(new_hidden_parent_dentry->d_inode,
new_hidden_dentry,
old_hidden_dentry->d_inode->i_mode,
kdev_t_to_nr(old_hidden_dentry->d_inode->
i_rdev));
#else
err = vfs_mknod(new_hidden_parent_dentry->d_inode,
new_hidden_dentry,
old_hidden_dentry->d_inode->i_mode,
old_hidden_dentry->d_inode->i_rdev);
#endif
} else if (S_ISREG(old_hidden_dentry->d_inode->i_mode)) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
err = vfs_create(new_hidden_parent_dentry->d_inode,
new_hidden_dentry, S_IRWXU);
#else
err = vfs_create(new_hidden_parent_dentry->d_inode,
new_hidden_dentry, S_IRWXU, NULL);
#endif
} else {
char diemsg[100];
snprintf(diemsg, sizeof(diemsg), "Unknown inode type %d\n",
old_hidden_dentry->d_inode->i_mode);
FISTBUG(diemsg);
}
current->fsuid = saved_uid;
current->fsgid = saved_gid;
unlock_dir(new_hidden_parent_dentry);
copyup_readlink_err:
KFREE(symbuf);
if (err) {
/* get rid of the hidden dentry and all its traces */
DPUT(new_hidden_dentry);
set_dtohd_index(dentry, new_bindex, NULL);
set_dbstart(dentry, old_bstart);
set_dbend(dentry, old_bend);
goto out;
}
/* We actually copyup the file here. */
if (S_ISREG(old_hidden_dentry->d_inode->i_mode)) {
mntget(stohiddenmnt_index(sb, old_bindex));
branchget(sb, old_bindex);
got_branch_input = old_bindex;
input_file =
DENTRY_OPEN(old_hidden_dentry,
stohiddenmnt_index(sb, old_bindex), O_RDONLY);
if (IS_ERR(input_file)) {
err = PTR_ERR(input_file);
goto out;
}
if (!input_file->f_op || !input_file->f_op->read) {
err = -EINVAL;
goto out;
}
/* copy the new file */
DGET(new_hidden_dentry);
mntget(stohiddenmnt_index(sb, new_bindex));
branchget(sb, new_bindex);
got_branch_output = new_bindex;
output_file =
DENTRY_OPEN(new_hidden_dentry,
stohiddenmnt_index(sb, new_bindex), O_WRONLY);
if (IS_ERR(output_file)) {
err = PTR_ERR(output_file);
goto out;
}
if (!output_file->f_op || !output_file->f_op->write) {
err = -EINVAL;
goto out;
}
/* allocating a buffer */
buf = (char *)KMALLOC(PAGE_SIZE, GFP_UNIONFS);
if (!buf) {
err = -ENOMEM;
goto out;
}
/* now read PAGE_SIZE bytes from offset 0 in a loop */
old_fs = get_fs();
input_file->f_pos = 0;
output_file->f_pos = 0;
set_fs(KERNEL_DS);
do {
if (len >= PAGE_SIZE)
size = PAGE_SIZE;
else if ((len < PAGE_SIZE) && (len > 0))
size = len;
len -= PAGE_SIZE;
read_bytes =
input_file->f_op->read(input_file, buf, size,
&input_file->f_pos);
if (read_bytes <= 0) {
err = read_bytes;
break;
}
write_bytes =
output_file->f_op->write(output_file, buf,
read_bytes,
&output_file->f_pos);
if (write_bytes < 0 || (write_bytes < read_bytes)) {
err = -EIO;
break;
}
} while ((read_bytes > 0) && (len > 0));
set_fs(old_fs);
KFREE(buf);
}
/* Set permissions. */
if ((err =
copyup_permissions(sb, old_hidden_dentry, new_hidden_dentry)))
goto out;
/* Selinux uses extended attributes for permissions. */
#if defined(UNIONFS_XATTR) && (LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,20))
if ((err = copyup_xattrs(old_hidden_dentry, new_hidden_dentry)))
goto out;
#endif
/* do not allow files getting deleted to be reinterposed */
if (!d_deleted(dentry))
unionfs_reinterpose(dentry);
out:
if (input_file && !IS_ERR(input_file)) {
fput(input_file);
} else {
/* since input file was not opened, we need to explicitly
* dput the old_hidden_dentry
*/
DPUT(old_hidden_dentry);
}
/* in any case, we have to branchput */
if (got_branch_input >= 0)
branchput(sb, got_branch_input);
if (output_file) {
if (copyup_file && !err) {
*copyup_file = output_file;
} else {
fput(output_file);
branchput(sb, got_branch_output);
}
}
fist_print_dentry("OUT: copyup_dentry", dentry);
fist_print_inode("OUT: copyup_dentry", dentry->d_inode);
print_exit_status(err);
return err;
}
STATIC struct dentry *
base0fs_lookup(inode_t *dir,
struct dentry *dentry,
struct nameidata* nd_unused_in_this_fxn /* XXX: fix code if ever used */ )
{
int err = 0;
struct dentry *lower_dir_dentry;
struct dentry *lower_dentry = NULL;
struct vfsmount *lower_mount;
const char *name;
vnode_t *this_vnode;
struct dentry *this_dir;
unsigned int namelen;
print_entry_location();
lower_dir_dentry = base0fs_lower_dentry(dentry->d_parent); /* CPW: Moved below print_entry_location */
name = dentry->d_name.name;
namelen = dentry->d_name.len;
fist_checkinode(dir, "base0fs_lookup");
this_vnode = dir;
this_dir = lower_dir_dentry;
fist_print_dentry("base0fs_lookup IN", dentry);
fist_print_dentry("base0fs_lookup: dentry->d_parent IN", dentry->d_parent);
fist_print_dentry("base0fs_lookup: lower_dir_dentry IN", lower_dir_dentry);
fist_print_inode("base0fs_lookup: dir IN", dir);
if (lower_dir_dentry->d_inode)
fist_print_inode("base0fs_lookup: lower_dir_dentry->d_inode",
lower_dir_dentry->d_inode);
/* must initialize dentry operations */
dentry->d_op = &base0fs_dops;
;
/* increase refcount of base dentry (lookup_one[_len] will decrement) */
// THIS IS RIGHT! (don't "fix" it)
// NO THIS IS WRONG IN 2.3.99-pre6. lookup_one[_len] will NOT decrement
// dget(lower_dir_dentry);
lock_inode(lower_dir_dentry->d_inode);
/* will allocate a new lower dentry if needed */
lower_dentry = lookup_one_len(name, lower_dir_dentry, namelen);
unlock_inode(lower_dir_dentry->d_inode);
if (IS_ERR(lower_dentry)) {
/*
* this produces an unusual dentry: one that has neither an
* inode, nor a private structure attached to it. All cleanup
* methods (d_delete, d_release, etc) must be prepared to deal
* with such dentries. Ion 09/29/2001
*/
err = PTR_ERR(lower_dentry);
goto out;
}
lower_mount = mntget(DENTRY_TO_LVFSMNT(dentry->d_parent));
;
if (lower_dentry->d_inode && lower_dentry->d_inode->i_sb) {
struct super_block *lower_sb = lower_dentry->d_inode->i_sb;
if (lower_sb->s_dev == sProcDev || lower_sb->s_dev == sDevDev) {
d_drop(dentry); /* Don't leak our dentry. */
return lower_dentry;
}
}
/* update parent directory's atime */
fist_copy_attr_atime(dir, lower_dir_dentry->d_inode);
/* link the upper and lower dentries */
DENTRY_TO_PRIVATE_SM(dentry) = (struct base0fs_dentry_info *) KMALLOC(sizeof(struct base0fs_dentry_info), GFP_KERNEL);
if (!DENTRY_TO_PRIVATE(dentry)) {
err = -ENOMEM;
goto out_dput;
}
DENTRY_TO_PRIVATE(dentry)->wdi_dentry = lower_dentry;
DENTRY_TO_PRIVATE(dentry)->wdi_mnt = lower_mount;
/* lookup is special: it needs to handle negative dentries */
if (!lower_dentry->d_inode) {
d_add(dentry, NULL);
fist_print_dentry("base0fs_lookup OUT lower_dentry", lower_dentry);
goto out;
}
fist_dprint(6, "lookup \"%s\" -> inode %lu\n", name, lower_dentry->d_inode->i_ino);
err = base0fs_interpose(lower_dentry, dentry, dir->i_sb, 1);
if (err)
goto out_free;
fist_checkinode(dentry->d_inode, "base0fs_lookup OUT: dentry->d_inode:");
fist_checkinode(dir, "base0fs_lookup OUT: dir");
fist_print_dentry("base0fs_lookup OUT lower_dentry", lower_dentry);
fist_print_inode("base0fs_lookup OUT lower_inode", lower_dentry->d_inode);
/* All is well */
goto out;
out_free:
d_drop(dentry); /* so that our bad dentry will get destroyed */
KFREE(DENTRY_TO_PRIVATE(dentry));
DENTRY_TO_PRIVATE_SM(dentry) = NULL; /* be safe */
out_dput:
if (lower_dentry)
dput(lower_dentry);
out:
fist_print_dentry("base0fs_lookup OUT", dentry);
print_exit_status(err);
return ERR_PTR(err);
}
/* sb we pass is unionfs's super_block */
int unionfs_interpose(struct dentry *dentry, struct super_block *sb, int flag)
{
struct inode *hidden_inode;
struct dentry *hidden_dentry;
int err = 0;
struct inode *inode;
int is_negative_dentry = 1;
int bindex, bstart, bend;
print_entry("flag = %d", flag);
verify_locked(dentry);
fist_print_dentry("In unionfs_interpose", dentry);
bstart = dbstart(dentry);
bend = dbend(dentry);
/* Make sure that we didn't get a negative dentry. */
for (bindex = bstart; bindex <= bend; bindex++) {
if (dtohd_index(dentry, bindex) &&
dtohd_index(dentry, bindex)->d_inode) {
is_negative_dentry = 0;
break;
}
}
BUG_ON(is_negative_dentry);
/* We allocate our new inode below, by calling iget.
* iget will call our read_inode which will initialize some
* of the new inode's fields
*/
/* On revalidate we've already got our own inode and just need
* to fix it up. */
if (flag == INTERPOSE_REVAL) {
inode = dentry->d_inode;
itopd(inode)->b_start = -1;
itopd(inode)->b_end = -1;
atomic_set(&itopd(inode)->uii_generation,
atomic_read(&stopd(sb)->usi_generation));
itohi_ptr(inode) =
KZALLOC(sbmax(sb) * sizeof(struct inode *), GFP_KERNEL);
if (!itohi_ptr(inode)) {
err = -ENOMEM;
goto out;
}
} else {
ino_t ino;
/* get unique inode number for unionfs */
#ifdef UNIONFS_IMAP
if (stopd(sb)->usi_persistent) {
err = read_uin(sb, bindex,
dtohd_index(dentry,
bindex)->d_inode->i_ino,
O_CREAT, &ino);
if (err)
goto out;
} else
#endif
ino = iunique(sb, UNIONFS_ROOT_INO);
inode = IGET(sb, ino);
if (!inode) {
err = -EACCES; /* should be impossible??? */
goto out;
}
}
down(&inode->i_sem);
if (atomic_read(&inode->i_count) > 1)
goto skip;
for (bindex = bstart; bindex <= bend; bindex++) {
hidden_dentry = dtohd_index(dentry, bindex);
if (!hidden_dentry) {
set_itohi_index(inode, bindex, NULL);
continue;
}
/* Initialize the hidden inode to the new hidden inode. */
if (!hidden_dentry->d_inode)
continue;
set_itohi_index(inode, bindex, IGRAB(hidden_dentry->d_inode));
}
ibstart(inode) = dbstart(dentry);
ibend(inode) = dbend(dentry);
/* Use attributes from the first branch. */
hidden_inode = itohi(inode);
/* Use different set of inode ops for symlinks & directories */
if (S_ISLNK(hidden_inode->i_mode))
inode->i_op = &unionfs_symlink_iops;
else if (S_ISDIR(hidden_inode->i_mode))
inode->i_op = &unionfs_dir_iops;
/* Use different set of file ops for directories */
if (S_ISDIR(hidden_inode->i_mode))
inode->i_fop = &unionfs_dir_fops;
/* properly initialize special inodes */
if (S_ISBLK(hidden_inode->i_mode) || S_ISCHR(hidden_inode->i_mode) ||
S_ISFIFO(hidden_inode->i_mode) || S_ISSOCK(hidden_inode->i_mode))
init_special_inode(inode, hidden_inode->i_mode,
hidden_inode->i_rdev);
/* Fix our inode's address operations to that of the lower inode (Unionfs is FiST-Lite) */
if (inode->i_mapping->a_ops != hidden_inode->i_mapping->a_ops) {
fist_dprint(7, "fixing inode 0x%p a_ops (0x%p -> 0x%p)\n",
inode, inode->i_mapping->a_ops,
hidden_inode->i_mapping->a_ops);
inode->i_mapping->a_ops = hidden_inode->i_mapping->a_ops;
}
/* all well, copy inode attributes */
fist_copy_attr_all(inode, hidden_inode);
skip:
/* only (our) lookup wants to do a d_add */
switch (flag) {
case INTERPOSE_DEFAULT:
case INTERPOSE_REVAL_NEG:
d_instantiate(dentry, inode);
break;
case INTERPOSE_LOOKUP:
err = PTR_ERR(d_splice_alias(inode, dentry));
break;
case INTERPOSE_REVAL:
/* Do nothing. */
break;
default:
printk(KERN_ERR "Invalid interpose flag passed!");
BUG();
}
fist_print_dentry("Leaving unionfs_interpose", dentry);
fist_print_inode("Leaving unionfs_interpose", inode);
up(&inode->i_sem);
out:
print_exit_status(err);
return err;
}