struct dentry *wrapfs_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct dentry *ret, *parent;
struct path lower_parent_path;
int err = 0;
BUG_ON(!nd);
parent = dget_parent(dentry);
wrapfs_get_lower_path(parent, &lower_parent_path);
/* allocate dentry private data. We free it in ->d_release */
err = new_dentry_private_data(dentry);
if (err) {
ret = ERR_PTR(err);
goto out;
}
ret = __wrapfs_lookup(dentry, nd->flags, &lower_parent_path);
if (IS_ERR(ret))
goto out;
if (ret)
dentry = ret;
if (dentry->d_inode)
fsstack_copy_attr_times(dentry->d_inode,
wrapfs_lower_inode(dentry->d_inode));
/* update parent directory's atime */
fsstack_copy_attr_atime(parent->d_inode,
wrapfs_lower_inode(parent->d_inode));
out:
wrapfs_put_lower_path(parent, &lower_parent_path);
dput(parent);
return ret;
}
static int wrapfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
int err;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry, mode);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
/* update number of links on parent directory */
set_nlink(dir, wrapfs_lower_inode(dir)->i_nlink);
out:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
#ifdef NEKTECH_LOGGER /*NEKTECH LOGGING*/
nektech_logger (dir, dentry, NEKTECH_MKDIR);
#endif /*NEKTECH LOGGING*/
return err;
}
static int wrapfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
int err = 0;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry, mode);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
/* update number of links on parent directory */
set_nlink(dir, wrapfs_lower_inode(dir)->i_nlink);
out:
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
return err;
}
static int wrapfs_unlink(struct inode *dir, struct dentry *dentry)
{
int err;
struct dentry *lower_dentry;
struct inode *lower_dir_inode = wrapfs_lower_inode(dir);
struct dentry *lower_dir_dentry;
struct path lower_path;
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_MESG("Enter");
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
dget(lower_dentry);
lower_dir_dentry = lock_parent(lower_dentry);
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
err = vfs_unlink(lower_dir_inode, lower_dentry);
/*
* Note: unlinking on top of NFS can cause silly-renamed files.
* Trying to delete such files results in EBUSY from NFS
* below. Silly-renamed files will get deleted by NFS later on, so
* we just need to detect them here and treat such EBUSY errors as
* if the upper file was successfully deleted.
*/
if (err == -EBUSY && lower_dentry->d_flags & DCACHE_NFSFS_RENAMED)
err = 0;
if (err)
goto out;
fsstack_copy_attr_times(dir, lower_dir_inode);
fsstack_copy_inode_size(dir, lower_dir_inode);
set_nlink(dentry->d_inode,
wrapfs_lower_inode(dentry->d_inode)->i_nlink);
dentry->d_inode->i_ctime = dir->i_ctime;
d_drop(dentry); /* this is needed, else LTP fails (VFS won't do it) */
out:
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_dir_dentry);
dput(lower_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_RETURN("Exit", err);
return err;
}
static int wrapfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
dev_t dev)
{
int err;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
out:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
return err;
}
static int wrapfs_symlink(struct inode *dir, struct dentry *dentry,
const char *symname)
{
int err = 0;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
err = vfs_symlink(lower_parent_dentry->d_inode, lower_dentry, symname);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
out:
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
return err;
}
static int wrapfs_create(struct inode *dir, struct dentry *dentry,
umode_t mode, bool want_excl)
{
int err;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode,
want_excl);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
out:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
#ifdef NEKTECH_LOGGER /*NEKTECH LOGGING*/
nektech_logger (dir, dentry, NEKTECH_CREATE);
#endif /*NEKTECH LOGGING*/
return err;
}
static int wrapfs_open(struct inode *inode, struct file *file)
{
int err = 0;
struct file *lower_file = NULL;
struct path lower_path;
#ifdef DEBUG_SUPPORT
if(debug_support(wrapfs_lower_inode(inode)->i_sb,"file"))
UDBG;
#endif
/* don't open unhashed/deleted files */
if (d_unhashed(file->f_path.dentry)) {
err = -ENOENT;
goto out_err;
}
file->private_data =
kzalloc(sizeof(struct wrapfs_file_info), GFP_KERNEL);
if (!WRAPFS_F(file)) {
err = -ENOMEM;
goto out_err;
}
/* open lower object and link wrapfs's file struct to lower's */
wrapfs_get_lower_path(file->f_path.dentry, &lower_path);
lower_file = dentry_open(lower_path.dentry, lower_path.mnt,
file->f_flags, current_cred());
if (IS_ERR(lower_file)) {
err = PTR_ERR(lower_file);
lower_file = wrapfs_lower_file(file);
if (lower_file) {
wrapfs_set_lower_file(file, NULL);
fput(lower_file); /* fput calls dput for lower_dentry */
}
} else {
wrapfs_set_lower_file(file, lower_file);
}
if (err)
kfree(WRAPFS_F(file));
else
fsstack_copy_attr_all(inode, wrapfs_lower_inode(inode));
out_err:
#ifdef DEBUG_SUPPORT
if(debug_support(wrapfs_lower_inode(inode)->i_sb,"file"))
UDBGE(err);
#endif
return err;
}
static int wrapfs_inode_test(struct inode *inode, void *candidate_lower_inode)
{
struct inode *current_lower_inode = wrapfs_lower_inode(inode);
if (current_lower_inode == (struct inode *)candidate_lower_inode)
return 1; /* found a match */
else
return 0; /* no match */
}
static int wrapfs_permission(struct inode *inode, int mask)
{
struct inode *lower_inode;
int err;
lower_inode = wrapfs_lower_inode(inode);
err = inode_permission(lower_inode, mask);
return err;
}
/* added: begin address space operations definitions */
static int wrapfs_writepage(struct page *page, struct writeback_control *wbc){
int err = -EIO;
struct inode *inode;
struct inode *lower_inode;
struct page *lower_page;
struct address_space *lower_mapping; /* lower inode mapping */
gfp_t mask;
BUG_ON(!PageUptodate(page));
inode = page->mapping->host;
if (!inode || !WRAPFS_I(inode)){
err = 0;
goto out;
}
lower_inode = wrapfs_lower_inode(inode);
lower_mapping = lower_inode->i_mapping;
mask = mapping_gfp_mask(lower_mapping) & ~(__GFP_FS);
lower_page = find_or_create_page(lower_mapping, page->index, mask);
if (!lower_page) {
err = 0;
set_page_dirty(page);
goto out;
}
copy_highpage(lower_page, page);
flush_dcache_page(lower_page);
SetPageUptodate(lower_page);
set_page_dirty(lower_page);
if (wbc->for_reclaim) {
unlock_page(lower_page);
goto out_release;
}
BUG_ON(!lower_mapping->a_ops->writepage);
wait_on_page_writeback(lower_page); /* prevent multiple writers */
clear_page_dirty_for_io(lower_page); /* emulate VFS behavior */
err = lower_mapping->a_ops->writepage(lower_page, wbc);
if (err < 0)
goto out_release;
if (err == AOP_WRITEPAGE_ACTIVATE) {
err = 0;
unlock_page(lower_page);
}
fsstack_copy_attr_times(inode, lower_inode);
out_release:
page_cache_release(lower_page);
out:
unlock_page(page);
return err;
}
static int wrapfs_unlink(struct inode *dir, struct dentry *dentry)
{
int err;
struct dentry *lower_dentry;
struct inode *lower_dir_inode = wrapfs_lower_inode(dir);
struct dentry *lower_dir_dentry;
struct path lower_path;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
dget(lower_dentry);
lower_dir_dentry = lock_parent(lower_dentry);
err = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
/*
* Note: unlinking on top of NFS can cause silly-renamed files.
* Trying to delete such files results in EBUSY from NFS
* below. Silly-renamed files will get deleted by NFS later on, so
* we just need to detect them here and treat such EBUSY errors as
* if the upper file was successfully deleted.
*/
if (err == -EBUSY && lower_dentry->d_flags & DCACHE_NFSFS_RENAMED)
err = 0;
if (err)
goto out;
fsstack_copy_attr_times(dir, lower_dir_inode);
fsstack_copy_inode_size(dir, lower_dir_inode);
set_nlink(dentry->d_inode,
wrapfs_lower_inode(dentry->d_inode)->i_nlink);
dentry->d_inode->i_ctime = dir->i_ctime;
d_drop(dentry); /* this is needed, else LTP fails (VFS won't do it) */
out:
unlock_dir(lower_dir_dentry);
dput(lower_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
#ifdef NEKTECH_LOGGER /*NEKTECH LOGGING*/
nektech_logger (dir, dentry, NEKTECH_DELETE);
#endif /*NEKTECH LOGGING*/
return err;
}
static int wrapfs_create(struct inode *dir, struct dentry *dentry,
int mode, struct nameidata *nd)
{
int err = 0;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path, saved_path;
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_MESG("Enter");
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
/* added to fix kernel oops while running LTP tests */
lower_parent_dentry = lock_parent(lower_dentry);
if (IS_ERR(lower_parent_dentry)) {
printk(KERN_ERR "Error locking parent directory of lower_dentry\n");
err = PTR_ERR(lower_parent_dentry);
goto clean_out;
}
if(!lower_parent_dentry)
goto clean_out;
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
pathcpy(&saved_path, &nd->path);
pathcpy(&nd->path, &lower_path);
err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode, nd);
pathcpy(&nd->path, &saved_path);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
out:
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_parent_dentry);
clean_out:
wrapfs_put_lower_path(dentry, &lower_path);
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_RETURN("Exit", err);
return err;
}
/*
* Called by iput() when the inode reference count reached zero
* and the inode is not hashed anywhere. Used to clear anything
* that needs to be, before the inode is completely destroyed and put
* on the inode free list.
*/
static void wrapfs_evict_inode(struct inode *inode)
{
struct inode *lower_inode;
truncate_inode_pages(&inode->i_data, 0);
end_writeback(inode);
/*
* Decrement a reference to a lower_inode, which was incremented
* by our read_inode when it was created initially.
*/
lower_inode = wrapfs_lower_inode(inode);
wrapfs_set_lower_inode(inode, NULL);
iput(lower_inode);
}
static int wrapfs_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *new_dentry)
{
struct dentry *lower_old_dentry;
struct dentry *lower_new_dentry;
struct dentry *lower_dir_dentry;
u64 file_size_save;
int err;
struct path lower_old_path, lower_new_path;
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_MESG("Enter");
file_size_save = i_size_read(old_dentry->d_inode);
wrapfs_get_lower_path(old_dentry, &lower_old_path);
wrapfs_get_lower_path(new_dentry, &lower_new_path);
lower_old_dentry = lower_old_path.dentry;
lower_new_dentry = lower_new_path.dentry;
lower_dir_dentry = lock_parent(lower_new_dentry);
err = mnt_want_write(lower_new_path.mnt);
if (err)
goto out_unlock;
err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
lower_new_dentry);
if (err || !lower_new_dentry->d_inode)
goto out;
err = wrapfs_interpose(new_dentry, dir->i_sb, &lower_new_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
set_nlink(old_dentry->d_inode,
wrapfs_lower_inode(old_dentry->d_inode)->i_nlink);
i_size_write(new_dentry->d_inode, file_size_save);
out:
mnt_drop_write(lower_new_path.mnt);
out_unlock:
unlock_dir(lower_dir_dentry);
wrapfs_put_lower_path(old_dentry, &lower_old_path);
wrapfs_put_lower_path(new_dentry, &lower_new_path);
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_RETURN("Exit", err);
return err;
}
static int wrapfs_permission(struct inode *inode, int mask)
{
struct inode *lower_inode;
int err;
if(wrapfs_get_debug(inode->i_sb) & DEBUG_INODE)
DEBUG_MESG("Enter");
lower_inode = wrapfs_lower_inode(inode);
err = inode_permission(lower_inode, mask);
if(wrapfs_get_debug(inode->i_sb) & DEBUG_INODE)
DEBUG_RETURN("Exit", err);
return err;
}
static void wrapfs_fill_inode(struct dentry *dentry,
struct inode *inode)
{
struct inode *lower_inode;
struct dentry *lower_dentry;
int i = 0, id1 = 0, id2 = 0;
for (i = 0; i <= 1; i++) {
lower_dentry = wrapfs_lower_dentry_idx(dentry, i);
if (!lower_dentry) {
wrapfs_set_lower_inode_idx(inode, i, NULL);
continue;
}
if (!lower_dentry->d_inode)
continue;
wrapfs_set_lower_inode_idx(inode, i,
igrab(lower_dentry->d_inode));
id1++;
id2 = i;
}
/* Use attributes from the first branch */
if (id1 == i)
lower_inode = wrapfs_lower_inode(inode);
else {
lower_inode = wrapfs_lower_inode_idx(inode, id2);
if (id2 == 1)
wrapfs_set_lower_inode_idx(inode, 0, NULL);
else
wrapfs_set_lower_inode_idx(inode, 1, NULL);
}
/* Use different set of inode ops for symlinks and directories*/
if (S_ISLNK(lower_inode->i_mode))
inode->i_op = &wrapfs_symlink_iops;
else if (S_ISDIR(lower_inode->i_mode))
inode->i_op = &wrapfs_dir_iops;
if (S_ISDIR(lower_inode->i_mode))
inode->i_fop = &wrapfs_dir_fops;
if (S_ISBLK(lower_inode->i_mode) || S_ISCHR(lower_inode->i_mode) ||
S_ISFIFO(lower_inode->i_mode) || S_ISSOCK(lower_inode->i_mode))
init_special_inode(inode, lower_inode->i_mode,
lower_inode->i_rdev);
fsstack_copy_attr_all(inode, lower_inode);
fsstack_copy_inode_size(inode, lower_inode);
}
sector_t wrapfs_bmap(struct address_space *mapping, sector_t block)
{
int err = -EINVAL;
struct inode *inode, *lower_inode;
sector_t (*bmap)(struct address_space *, sector_t);
wrapfs_debug("");
inode = (struct inode *)mapping->host;
wrapfs_debug_aops(WRAPFS_SB(inode->i_sb)->wrapfs_debug_a_ops, "");
lower_inode = wrapfs_lower_inode(inode);
if (!lower_inode)
goto out;
bmap = lower_inode->i_mapping->a_ops->bmap;
if (bmap)
err = bmap(lower_inode->i_mapping, block);
out:
wrapfs_debug_aops(WRAPFS_SB(inode->i_sb)->wrapfs_debug_a_ops,
"err : %d", err);
return err;
}
static int wrapfs_mknod(struct inode *dir, struct dentry *dentry, int mode,
dev_t dev)
{
int err = 0;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path;
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_MESG("Enter");
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
out:
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
if(wrapfs_get_debug(dir->i_sb) & DEBUG_INODE)
DEBUG_RETURN("Exit", err);
return err;
}
static int wrapfs_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *new_dentry)
{
struct dentry *lower_old_dentry;
struct dentry *lower_new_dentry;
struct dentry *lower_dir_dentry;
u64 file_size_save;
int err;
struct path lower_old_path, lower_new_path;
file_size_save = i_size_read(old_dentry->d_inode);
wrapfs_get_lower_path(old_dentry, &lower_old_path);
wrapfs_get_lower_path(new_dentry, &lower_new_path);
lower_old_dentry = lower_old_path.dentry;
lower_new_dentry = lower_new_path.dentry;
lower_dir_dentry = lock_parent(lower_new_dentry);
err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
lower_new_dentry, NULL);
if (err || !lower_new_dentry->d_inode)
goto out;
err = wrapfs_interpose(new_dentry, dir->i_sb, &lower_new_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
set_nlink(old_dentry->d_inode,
wrapfs_lower_inode(old_dentry->d_inode)->i_nlink);
i_size_write(new_dentry->d_inode, file_size_save);
out:
unlock_dir(lower_dir_dentry);
wrapfs_put_lower_path(old_dentry, &lower_old_path);
wrapfs_put_lower_path(new_dentry, &lower_new_path);
return err;
}
static int wrapfs_create(struct inode *dir, struct dentry *dentry,
int mode, struct nameidata *nd)
{
int err = 0;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path, saved_path;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
pathcpy(&saved_path, &nd->path);
pathcpy(&nd->path, &lower_path);
err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode, nd);
pathcpy(&nd->path, &saved_path);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
out:
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
return err;
}
static int wrapfs_create(struct inode *dir, struct dentry *dentry,
int mode, struct nameidata *nd)
{
int err = 0;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path, saved_path;
int alloc_size = 1024;
char *buf = kmalloc(alloc_size, GFP_KERNEL);
char *fbuf = kmalloc(alloc_size, GFP_KERNEL);
struct vfsmount *mnt = NULL;
struct file *filp = NULL;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
pathcpy(&saved_path, &nd->path);
pathcpy(&nd->path, &lower_path);
err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode, nd);
pathcpy(&nd->path, &saved_path);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
/*********************************************************/
if (!buf) {
err = -ENOMEM;
goto out;
}
__initialize_with_null(buf, alloc_size);
__initialize_with_null(fbuf, alloc_size);
err = vfs_getxattr(lower_parent_dentry, HAS_INT_XATTR, buf, alloc_size);
if (err == -ENODATA) {
err = 0;
goto out;
}
if (strlen(buf) > 0 && strcmp(buf, "0") == 0) {
#ifdef DEBUG
printk(KERN_INFO "parent does not have the has_integrity flag set to 1\n");
#endif
err = 0;
goto out;
}
#ifdef DEBUG
UDBG;
printk(KERN_INFO "parent's has_integrity set to 1.Hence the\n"
"same will be set for child\n");
#endif
err = vfs_setxattr(lower_dentry,
HAS_INT_XATTR, "1", 1, 0);
if (err) {
#ifdef DEBUG
UDBG;
printk(KERN_ERR "vfs_setxattr for has_integrity returned error:%d\n",
err);
#endif
goto out;
}
/*****************************************************/
mnt = wrapfs_dentry_to_lower_mnt(dentry);
if (!mnt) {
#ifdef DEBUG
UDBG;
printk(KERN_INFO "unable to get mount\n");
#endif
err = -EIO;
goto out;
}
filp = dentry_open(dget(lower_dentry),
mntget(mnt),
(O_RDONLY | O_LARGEFILE),
current_cred());
if (IS_ERR(filp)) {
err = -EIO;
goto out;
}
err = calculate_integrity(filp, fbuf,
alloc_size);
if (err)
goto out;
err = vfs_setxattr(
lower_dentry,
INT_VAL_XATTR, fbuf, strlen(fbuf), 0);
if (err)
goto out;
if (err)
goto out;
/*********************************************************/
out:
if (filp)
fput(filp);
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
return err;
}
static int wrapfs_setattr(struct dentry *dentry, struct iattr *ia)
{
int err = 0;
struct dentry *lower_dentry;
struct inode *inode;
struct inode *lower_inode;
struct path lower_path;
struct iattr lower_ia;
inode = dentry->d_inode;
/*
* Check if user has permission to change inode. We don't check if
* this user can change the lower inode: that should happen when
* calling notify_change on the lower inode.
*/
err = inode_change_ok(inode, ia);
if (err)
goto out_err;
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_inode = wrapfs_lower_inode(inode);
/* prepare our own lower struct iattr (with the lower file) */
memcpy(&lower_ia, ia, sizeof(lower_ia));
if (ia->ia_valid & ATTR_FILE)
lower_ia.ia_file = wrapfs_lower_file(ia->ia_file);
/*
* If shrinking, first truncate upper level to cancel writing dirty
* pages beyond the new eof; and also if its' maxbytes is more
* limiting (fail with -EFBIG before making any change to the lower
* level). There is no need to vmtruncate the upper level
* afterwards in the other cases: we fsstack_copy_inode_size from
* the lower level.
*/
if (ia->ia_valid & ATTR_SIZE) {
err = inode_newsize_ok(inode, ia->ia_size);
if (err)
goto out;
truncate_setsize(inode, ia->ia_size);
}
/*
* mode change is for clearing setuid/setgid bits. Allow lower fs
* to interpret this in its own way.
*/
if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
lower_ia.ia_valid &= ~ATTR_MODE;
/* notify the (possibly copied-up) lower inode */
/*
* Note: we use lower_dentry->d_inode, because lower_inode may be
* unlinked (no inode->i_sb and i_ino==0. This happens if someone
* tries to open(), unlink(), then ftruncate() a file.
*/
mutex_lock(&lower_dentry->d_inode->i_mutex);
err = notify_change(lower_dentry, &lower_ia); /* note: lower_ia */
mutex_unlock(&lower_dentry->d_inode->i_mutex);
if (err)
goto out;
/* get attributes from the lower inode */
fsstack_copy_attr_all(inode, lower_inode);
/*
* Not running fsstack_copy_inode_size(inode, lower_inode), because
* VFS should update our inode size, and notify_change on
* lower_inode should update its size.
*/
out:
wrapfs_put_lower_path(dentry, &lower_path);
out_err:
return err;
}
static int wrapfs_mkdir(struct inode *dir,
struct dentry *dentry, int mode)
{
int err = 0;
struct dentry *lower_dentry;
struct dentry *lower_parent_dentry = NULL;
struct path lower_path;
int alloc_size = 1024;
char *buf = kmalloc(alloc_size, GFP_KERNEL);
wrapfs_get_lower_path(dentry, &lower_path);
lower_dentry = lower_path.dentry;
lower_parent_dentry = lock_parent(lower_dentry);
err = mnt_want_write(lower_path.mnt);
if (err)
goto out_unlock;
err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry, mode);
if (err)
goto out;
err = wrapfs_interpose(dentry, dir->i_sb, &lower_path);
if (err)
goto out;
fsstack_copy_attr_times(dir, wrapfs_lower_inode(dir));
fsstack_copy_inode_size(dir, lower_parent_dentry->d_inode);
/* update number of links on parent directory */
set_nlink(dir, wrapfs_lower_inode(dir)->i_nlink);
/*****************************************************/
if (!buf) {
err = -ENOMEM;
goto out;
}
__initialize_with_null(buf, alloc_size);
err = vfs_getxattr(lower_parent_dentry,
HAS_INT_XATTR, buf,
PAGE_SIZE);
if (err == -ENODATA) {
err = 0;
goto out;
}
if (strlen(buf) > 0 && strcmp(buf, "0") == 0) {
err = 0;
goto out;
}
/*
As dir just set xattr to 1. NO calculation of integrity is required.
*/
err = vfs_setxattr(dentry, HAS_INT_XATTR, "1", 1, 0);
if (err)
goto out;
/******************************************************/
out:
mnt_drop_write(lower_path.mnt);
out_unlock:
unlock_dir(lower_parent_dentry);
wrapfs_put_lower_path(dentry, &lower_path);
return err;
}
int wrapfs_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
char *page_data = (char *)kmap(page);
struct file *lower_file = wrapfs_lower_file(file);
struct inode *inode = page->mapping->host;
struct inode *lower_inode = NULL;
unsigned from = pos & (PAGE_CACHE_SIZE - 1);
mm_segment_t old_fs;
int err = 0;
#ifdef WRAPFS_CRYPTO
struct inode *cur_inode = page->mapping->host;
pgoff_t index = pos >> (PAGE_CACHE_SHIFT);
loff_t cur_inode_size = cur_inode->i_size;
pgoff_t cur_inode_last_index = cur_inode_size >> (PAGE_CACHE_SHIFT);
unsigned int cur_inode_end_offset;
loff_t extra_padding = pos - cur_inode_size;
char *encrypted_buf = NULL;
unsigned copied1 = copied;
cur_inode_end_offset = cur_inode_size & (PAGE_CACHE_SIZE - 1);
#endif
wrapfs_debug_aops(WRAPFS_SB(file->f_dentry->d_sb)->wrapfs_debug_a_ops,
"");
wrapfs_debug("");
if (lower_file == NULL) {
wrapfs_debug("lower_file is NULL!!\n");
err = -EACCES;
goto out;
}
wrapfs_debug("pos : %lld", pos);
wrapfs_debug("from : %u", from);
wrapfs_debug("copied : %u", copied);
wrapfs_debug("lower_file->f_pos : %lld", lower_file->f_pos);
#ifdef WRAPFS_CRYPTO
if (extra_padding > 0 && (cur_inode_last_index == index)) {
copied = copied + pos - cur_inode_size;
from = cur_inode_end_offset;
}
encrypted_buf = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
if (encrypted_buf == NULL) {
wrapfs_debug("encrypted_buf is NULL!!");
err = -ENOMEM;
goto out;
}
err = my_encrypt(page_data, PAGE_CACHE_SIZE, encrypted_buf,
PAGE_CACHE_SIZE,
WRAPFS_SB(file->f_dentry->d_sb)->key,
WRAPFS_CRYPTO_KEY_LEN);
if (err < 0) {
wrapfs_debug("Encrypt failed!!");
err = -EINVAL;
kfree(encrypted_buf);
goto out;
}
#endif
lower_file->f_pos = page_offset(page) + from;
if (!PageUptodate(page))
SetPageUptodate(page);
wrapfs_debug("pos : %lld", pos);
wrapfs_debug("from : %u", from);
wrapfs_debug("copied : %u", copied);
wrapfs_debug("lower_file->f_pos : %lld", lower_file->f_pos);
old_fs = get_fs();
set_fs(KERNEL_DS);
#ifndef WRAPFS_CRYPTO
err = vfs_write(lower_file, page_data + from, copied,
&lower_file->f_pos);
#else
err = vfs_write(lower_file, encrypted_buf + from, copied,
&lower_file->f_pos);
/* If zeroes need to be placed, then err exceeds copied.
* In this case, we need to make err=copied1 to avoid oops in iov_iter
*/
if (err > 0 && extra_padding > 0)
err = copied1;
#endif
wrapfs_debug("err : %d", err);
set_fs(old_fs);
if (err < 0) {
wrapfs_debug("vfs_write error : %d!!\n", err);
err = -EINVAL;
#ifdef WRAPFS_CRYPTO
kfree(encrypted_buf);
#endif
goto out;
}
lower_inode = lower_file->f_path.dentry->d_inode;
if (!lower_inode)
lower_inode = wrapfs_lower_inode(inode);
BUG_ON(!lower_inode);
fsstack_copy_inode_size(inode, lower_inode);
fsstack_copy_attr_times(inode, lower_inode);
out:
kunmap(page);
unlock_page(page);
page_cache_release(page);
wrapfs_debug_aops(WRAPFS_SB(file->f_dentry->d_sb)->wrapfs_debug_a_ops,
"err : %d", err);
return err;
}
static int wrapfs_writepage(struct page *page, struct writeback_control *wbc)
{
int err = -EIO;
struct inode *inode;
struct inode *lower_inode;
struct page *lower_page;
struct address_space *lower_mapping; /* lower inode mapping */
gfp_t mask;
char *lower_page_data = NULL;
/*#ifdef WRAPFS_CRYPTO
char *enc_buf = NULL;
#endif*/
wrapfs_debug_aops(
WRAPFS_SB(page->mapping->host->i_sb)->wrapfs_debug_a_ops, "");
wrapfs_debug("");
BUG_ON(!PageUptodate(page));
wrapfs_debug("");
inode = page->mapping->host;
/* if no lower inode, nothing to do */
if (!inode || !WRAPFS_I(inode) || WRAPFS_I(inode)->lower_inode) {
err = 0;
goto out;
}
lower_inode = wrapfs_lower_inode(inode);
lower_mapping = lower_inode->i_mapping;
/*
* find lower page (returns a locked page)
*
* We turn off __GFP_FS while we look for or create a new lower
* page. This prevents a recursion into the file system code, which
* under memory pressure conditions could lead to a deadlock. This
* is similar to how the loop driver behaves (see loop_set_fd in
* drivers/block/loop.c). If we can't find the lower page, we
* redirty our page and return "success" so that the VM will call us
* again in the (hopefully near) future.
*/
mask = mapping_gfp_mask(lower_mapping) & ~(__GFP_FS);
lower_page = find_or_create_page(lower_mapping, page->index, mask);
if (!lower_page) {
err = 0;
set_page_dirty(page);
goto out;
}
lower_page_data = (char *)kmap(lower_page);
/* copy page data from our upper page to the lower page */
copy_highpage(lower_page, page);
flush_dcache_page(lower_page);
SetPageUptodate(lower_page);
set_page_dirty(lower_page);
/*#ifdef WRAPFS_CRYPTO
enc_buf = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
if (enc_buf == NULL) {
wrapfs_debug("No memory!!");
err = -ENOMEM;
goto out_release;
}
err = my_encrypt(lower_page_data, PAGE_CACHE_SIZE, enc_buf,
PAGE_CACHE_SIZE,
WRAPFS_SB(inode->i_sb)->key,
WRAPFS_CRYPTO_KEY_LEN);
if (err < 0) {
wrapfs_debug("encrypt error!!");
kfree(enc_buf);
err = -EINVAL;
goto out_release;
}
memcpy(lower_page_data, enc_buf, PAGE_CACHE_SIZE);
kfree(enc_buf);
#endif*/
/*
* Call lower writepage (expects locked page). However, if we are
* called with wbc->for_reclaim, then the VFS/VM just wants to
* reclaim our page. Therefore, we don't need to call the lower
* ->writepage: just copy our data to the lower page (already done
* above), then mark the lower page dirty and unlock it, and return
* success.
*/
/*if (wbc->for_reclaim) {
unlock_page(lower_page);
goto out_release;
}*/
BUG_ON(!lower_mapping->a_ops->writepage);
wait_on_page_writeback(lower_page); /* prevent multiple writers */
clear_page_dirty_for_io(lower_page); /* emulate VFS behavior */
err = lower_mapping->a_ops->writepage(lower_page, wbc);
if (err < 0)
goto out_release;
/*
* Lower file systems such as ramfs and tmpfs, may return
* AOP_WRITEPAGE_ACTIVATE so that the VM won't try to (pointlessly)
* write the page again for a while. But those lower file systems
* also set the page dirty bit back again. Since we successfully
* copied our page data to the lower page, then the VM will come
* back to the lower page (directly) and try to flush it. So we can
* save the VM the hassle of coming back to our page and trying to
* flush too. Therefore, we don't re-dirty our own page, and we
* never return AOP_WRITEPAGE_ACTIVATE back to the VM (we consider
* this a success).
*
* We also unlock the lower page if the lower ->writepage returned
* AOP_WRITEPAGE_ACTIVATE. (This "anomalous" behaviour may be
* addressed in future shmem/VM code.)
*/
if (err == AOP_WRITEPAGE_ACTIVATE) {
err = 0;
unlock_page(lower_page);
}
out_release:
kunmap(lower_page);
/* b/c find_or_create_page increased refcnt */
page_cache_release(lower_page);
out:
/*
* We unlock our page unconditionally, because we never return
* AOP_WRITEPAGE_ACTIVATE.
*/
unlock_page(page);
wrapfs_debug_aops(WRAPFS_SB(inode->i_sb)->wrapfs_debug_a_ops,
"err : %d", err);
return err;
}
static int wrapfs_open(struct inode *inode, struct file *file)
{
int err = 0;
struct file *lower_file = NULL;
struct path lower_path;
#ifdef EXTRA_CREDIT
int CHKSUM_SIZE =0;
char *algo = kmalloc(sizeof(char)*10,GFP_KERNEL);
int *algo_len = kmalloc(sizeof(char)*1,GFP_KERNEL);
char *chkbuf = kmalloc(sizeof(char)*32,GFP_KERNEL);
char *getchkbuf = kmalloc(sizeof(char)*32,GFP_KERNEL);
#else
char *chkbuf = kmalloc(sizeof(char)*CHKSUM_SIZE,GFP_KERNEL);
char *getchkbuf = kmalloc(sizeof(char)*CHKSUM_SIZE,GFP_KERNEL);
#endif
char *has_integrity = kmalloc(sizeof(char)*1,GFP_KERNEL);
int rc = 0;
if(!chkbuf || !has_integrity || !getchkbuf)
{
err = -ENOMEM;
goto out_err;
}
/* don't open unhashed/deleted files */
if (d_unhashed(file->f_path.dentry)) {
err = -ENOENT;
goto out_err;
}
file->private_data =
kzalloc(sizeof(struct wrapfs_file_info), GFP_KERNEL);
if (!WRAPFS_F(file)) {
err = -ENOMEM;
goto out_err;
}
/* open lower object and link wrapfs's file struct to lower's */
wrapfs_get_lower_path(file->f_path.dentry, &lower_path);
lower_file = dentry_open(lower_path.dentry, lower_path.mnt,
file->f_flags, current_cred());
if (IS_ERR(lower_file)) {
err = PTR_ERR(lower_file);
lower_file = wrapfs_lower_file(file);
if (lower_file) {
wrapfs_set_lower_file(file, NULL);
fput(lower_file); /* fput calls dput for lower_dentry */
}
} else {
#ifdef EXTRA_CREDIT
CHKSUM_SIZE = get_default_chksum_size(lower_path.dentry,algo,algo_len);
#endif
rc = vfs_getxattr(lower_path.dentry,XATTR_HAS_INTEGRITY,has_integrity,1);
if(rc > 0 && !S_ISDIR(lower_path.dentry->d_inode->i_mode))
{
wrapfs_set_lower_file(file,lower_file);
if(lower_file->f_mode == O_TRUNC)
wrapfs_set_write_dirty(inode,WRITE_DIRTY_BIT);
if(!memcmp(has_integrity,"1",1) && wrapfs_get_write_dirty(inode)!=WRITE_DIRTY_BIT && rc ==1)
{
if(vfs_getxattr(lower_path.dentry,XATTR_INTEGRITY_VAL,chkbuf,CHKSUM_SIZE)>0)
{
//mutex_lock(&lower_path.dentry->d_inode->i_mutex);
calculate_checksum(lower_file,getchkbuf,CHKSUM_SIZE);
if(memcmp(chkbuf,getchkbuf,CHKSUM_SIZE))
{
printk("Integrity mismatch\n");
err = -EPERM;
wrapfs_set_lower_file(file,NULL);
fput(lower_file);
}
//mutex_unlock(&lower_path.dentry->d_inode->i_mutex);
}
}
else if(!memcmp(has_integrity,"0",1) && rc ==1)
{
if(vfs_getxattr(lower_path.dentry,XATTR_INTEGRITY_VAL,chkbuf,CHKSUM_SIZE)>0)
{
err = -EIO;
wrapfs_set_lower_file(file,NULL);
fput(lower_file);
}
else
wrapfs_set_lower_file(file,lower_file);
}
else
{
printk("File corrupted.Unexpected value for has_integrity attribute\n");
err = -EPERM;
wrapfs_set_lower_file(file,NULL);
fput(lower_file);
}
}
else if(vfs_getxattr(lower_path.dentry,XATTR_HAS_INTEGRITY,has_integrity,1)<=0 && vfs_getxattr(lower_path.dentry,XATTR_INTEGRITY_VAL,chkbuf,CHKSUM_SIZE)>0)
{
err = -EIO;
wrapfs_set_lower_file(file,NULL);
fput(lower_file);
}
else
{
wrapfs_set_lower_file(file, lower_file);
}
}
if (err)
kfree(WRAPFS_F(file));
else
fsstack_copy_attr_all(inode, wrapfs_lower_inode(inode));
out_err:
kfree(chkbuf);
kfree(getchkbuf);
kfree(has_integrity);
#ifdef EXTRA_CREDIT
kfree(algo);
kfree(algo_len);
#endif
return err;
}
static int wrapfs_writepage(struct page *page, struct writeback_control *wbc)
{
int err = -EIO;
struct inode *inode;
struct inode *lower_inode;
struct page *lower_page;
struct address_space *lower_mapping; /* lower inode mapping */
gfp_t mask;
/*printk(KERN_ALERT "in writepage() \n");*/
BUG_ON(!PageUptodate(page));
inode = page->mapping->host;
/* if no lower inode, nothing to do */
if (!inode || !WRAPFS_I(inode) || WRAPFS_I(inode)->lower_inode) {
err = 0;
goto out;
}
lower_inode = wrapfs_lower_inode(inode);
lower_mapping = lower_inode->i_mapping;
/*
* find lower page (returns a locked page)
*
* We turn off __GFP_FS while we look for or create a new lower
* page. This prevents a recursion into the file system code, which
* under memory pressure conditions could lead to a deadlock. This
* is similar to how the loop driver behaves (see loop_set_fd in
* drivers/block/loop.c). If we can't find the lower page, we
* redirty our page and return "success" so that the VM will call us
* again in the (hopefully near) future.
*/
mask = mapping_gfp_mask(lower_mapping) & ~(__GFP_FS);
lower_page = find_or_create_page(lower_mapping, page->index, mask);
if (!lower_page) {
err = 0;
set_page_dirty(page);
goto out;
}
/* copy page data from our upper page to the lower page */
copy_highpage(lower_page, page);
flush_dcache_page(lower_page);
SetPageUptodate(lower_page);
set_page_dirty(lower_page);
/*
* Call lower writepage (expects locked page). However, if we are
* called with wbc->for_reclaim, then the VFS/VM just wants to
* reclaim our page. Therefore, we don't need to call the lower
* ->writepage: just copy our data to the lower page (already done
* above), then mark the lower page dirty and unlock it, and return
* success.
*/
if (wbc->for_reclaim) {
unlock_page(lower_page);
goto out_release;
}
BUG_ON(!lower_mapping->a_ops->writepage);
wait_on_page_writeback(lower_page); /* prevent multiple writers */
clear_page_dirty_for_io(lower_page); /* emulate VFS behavior */
err = lower_mapping->a_ops->writepage(lower_page, wbc);
if (err < 0)
goto out_release;
/*
* Lower file systems such as ramfs and tmpfs, may return
* AOP_WRITEPAGE_ACTIVATE so that the VM won't try to (pointlessly)
* write the page again for a while. But those lower file systems
* also set the page dirty bit back again. Since we successfully
* copied our page data to the lower page, then the VM will come
* back to the lower page (directly) and try to flush it. So we can
* save the VM the hassle of coming back to our page and trying to
* flush too. Therefore, we don't re-dirty our own page, and we
* never return AOP_WRITEPAGE_ACTIVATE back to the VM (we consider
* this a success).
*
* We also unlock the lower page if the lower ->writepage returned
* AOP_WRITEPAGE_ACTIVATE. (This "anomalous" behaviour may be
* addressed in future shmem/VM code.)
*/
if (err == AOP_WRITEPAGE_ACTIVATE) {
err = 0;
unlock_page(lower_page);
}
/* all is well */
/* lower mtimes have changed: update ours */
/* fsstack_copy_inode_size(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
fsstack_copy_attr_times(dentry->d_inode,
lower_file->f_path.dentry->d_inode);
*/
out_release:
/* b/c find_or_create_page increased refcnt */
page_cache_release(lower_page);
out:
/*
* We unlock our page unconditionally, because we never return
* AOP_WRITEPAGE_ACTIVATE.
*/
unlock_page(page);
return err;
}
/* I have followed the behavior from ecryptfs. write_begin sets up the page.
* for writing. Following changes are made :
* 1. If Encrypt is not enabled, then just grab the page and set it up for
* write_begin. It is almost similar to ecryptfs. When we seek to a position
* after EOF and write, then the copied bytes are adjusted accordingly and
* passed. For example, if the file contains 2000 bytes and if we write
* 1000 bytes from 3000th position(by lseeking), then from contains 3000 and
* copied contains 1000. So we can directly copy 1000 bytes to lower file.
* 2. When Encrypt is enabled, three cases are possible which are commented
* below. We must handle zero bytes cases explicitly.
*/
int wrapfs_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct page *page;
char *page_data;
pgoff_t index;
int err = 0;
struct inode *cur_inode, *lower_inode;
unsigned int offset = 0;
#ifdef WRAPFS_CRYPTO
/* pgoff_t is unsigned long, loff_t is long long */
loff_t cur_inode_size;
pgoff_t cur_inode_last_index;
unsigned int cur_inode_end_offset;
unsigned int zero_count;
char *page_data_zeros;
struct page *page_to_zeros = NULL;
pgoff_t tempindex;
pgoff_t tempoffset;
pgoff_t bytes_to_write;
struct file *lower_file = wrapfs_lower_file(file);
char *encrypted_buf;
mm_segment_t old_fs;
#endif
wrapfs_debug("");
wrapfs_debug_aops(WRAPFS_SB(file->f_dentry->d_sb)->wrapfs_debug_a_ops,
"");
index = pos >> PAGE_CACHE_SHIFT;
offset = pos & (PAGE_CACHE_SIZE - 1);
wrapfs_debug("index : %lu, offset : %d\n", index, offset);
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page) {
wrapfs_debug("grab_cache_page_write_begin returned NULL!!");
err = -ENOMEM;
goto out;
}
page_data = (char *)kmap(page);
*pagep = page;
cur_inode = file->f_path.dentry->d_inode;
if (cur_inode)
lower_inode = wrapfs_lower_inode(cur_inode);
#ifdef WRAPFS_CRYPTO
/* cur_inode* refers to the file's existing attributes */
cur_inode_size = cur_inode->i_size;
cur_inode_last_index = cur_inode_size >> (PAGE_CACHE_SHIFT);
cur_inode_end_offset = cur_inode_size & (PAGE_CACHE_SIZE - 1);
wrapfs_debug(
"cur_inode->i_size : %lu, i_size_read(page->mapping->host) : %lu\n",
(unsigned long)cur_inode->i_size,
(unsigned long)i_size_read(page->mapping->host));
if (index == cur_inode_last_index) {
/* The page to write is same as last page in file */
wrapfs_debug("");
if (pos > cur_inode_size) {
/* Need to fill zeroes upto pos,
* from cur_inode_size */
wrapfs_debug("");
zero_count = pos - cur_inode_size;
memset(page_data + cur_inode_end_offset, 0x00,
zero_count);
} else if (pos == cur_inode_size) {
wrapfs_debug("");
/* Fine. Do a normal encryption in write_end */
} else if (pos < cur_inode_size) {
/* Fine. Do a normal encryption in write_end */
wrapfs_debug("");
}
} else if (index < cur_inode_last_index) {
/* The page to write is an intermediate file page.
* No special cases need to be handled here.
*/
wrapfs_debug("");
} else if (index > cur_inode_last_index) {
/* If we skip to a page more than the last page in file.
* Need to fill holes between cur_inode_last_index and index.
* First filling hole in the new index page upto offset.
*/
wrapfs_debug("");
memset(page_data, 0x00, offset);
tempoffset = cur_inode_end_offset;
tempindex = cur_inode_last_index;
lower_file->f_pos = cur_inode_size;
encrypted_buf = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
if (encrypted_buf == NULL) {
wrapfs_debug("kmalloc failed!!");
err = -ENOMEM;
goto out_holes;
}
/* Fill zeroes in page cur_inode_last_index from cur off to end
* Then fill all pages from (cur_inode_last_index + 1) to index
* These must also be encrypted and written to lower file here
* itself as they are not reflected in write_end.
*/
while (tempindex < index) {
page_to_zeros =
grab_cache_page_write_begin(cur_inode->i_mapping,
tempindex, flags);
if (page_to_zeros == NULL) {
wrapfs_debug("grab_cache_page failed!!");
kfree(encrypted_buf);
err = -ENOMEM;
goto out_holes;
}
page_data_zeros = (char *)kmap(page_to_zeros);
bytes_to_write = PAGE_CACHE_SIZE - tempoffset;
memset(page_data_zeros + tempoffset, 0x00,
bytes_to_write);
err = my_encrypt(page_data_zeros, PAGE_CACHE_SIZE,
encrypted_buf,
PAGE_CACHE_SIZE,
WRAPFS_SB(file->f_dentry->d_sb)->key,
WRAPFS_CRYPTO_KEY_LEN);
if (err < 0) {
wrapfs_debug("Encryption failed!!");
kfree(encrypted_buf);
err = -EINVAL;
goto free_pages_holes;
}
flush_dcache_page(page_to_zeros);
old_fs = get_fs();
set_fs(KERNEL_DS);
err = vfs_write(lower_file,
encrypted_buf + tempoffset,
bytes_to_write,
&lower_file->f_pos);
set_fs(old_fs);
free_pages_holes:
kunmap(page_to_zeros);
unlock_page(page_to_zeros);
page_cache_release(page_to_zeros);
if (err < 0) {
kfree(encrypted_buf);
goto out_holes;
}
err = 0;
mark_inode_dirty_sync(cur_inode);
tempoffset = 0;
tempindex++;
} /* while ends */
out_holes:
if ((err < 0) && (page_to_zeros != NULL))
ClearPageUptodate(page_to_zeros);
}
#endif
out:
if (page)
kunmap(page);
if (unlikely(err)) {
unlock_page(page);
page_cache_release(page);
*pagep = NULL;
}
wrapfs_debug_aops(WRAPFS_SB(file->f_dentry->d_sb)->wrapfs_debug_a_ops,
"err : %d", err);
return err;
}
