static int ext2_unlink(struct inode * dir, struct dentry *dentry)
{
struct inode * inode = dentry->d_inode;
struct ext2_dir_entry_2 * de;
struct page * page;
int err = -ENOENT;
de = ext2_find_entry (dir, dentry, &page);
if (!de)
goto out;
err = ext2_delete_entry (de, page);
if (err)
goto out;
inode->i_ctime = dir->i_ctime;
// Removing the backlink from the inode
ext2bp_debug("Removing backlink from the inode\n");
int i, link_pos = -1;
struct ext2_inode_info *ei = EXT2_I(inode);
for(i=0; i < inode->i_nlink; i++) {
if (ei->i_backlinks[i] == dir->i_ino) {
link_pos = i;
ext2bp_debug("Found backlink to inode %d at position %d\n", dir->i_ino, i);
break;
}
}
// If we find the backlink, remove it and move the other
// backlinks up a bit.
if (link_pos != -1) {
for(i=link_pos; i < (EXT2_N_LINKS - 1); i++) {
ei->i_backlinks[i] = ei->i_backlinks[i+1];
}
}
mark_inode_dirty(inode);
inode_dec_link_count(inode);
err = 0;
out:
return err;
}
static int ext2_unlink(struct inode * dir, struct dentry *dentry)
{
struct inode * inode = dentry->d_inode;
struct ext2_dir_entry_2 * de;
struct page * page;
int err = -ENOENT;
de = ext2_find_entry (dir, dentry, &page);
if (!de)
goto out;
err = ext2_delete_entry (de, page);
if (err)
goto out;
inode->i_ctime = dir->i_ctime;
ext2_dec_count(inode);
err = 0;
out:
return err;
}
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
struct inode * old_inode = old_dentry->d_inode;
struct inode * new_inode = new_dentry->d_inode;
struct page * dir_page = NULL;
struct ext2_dir_entry_2 * dir_de = NULL;
struct page * old_page;
struct ext2_dir_entry_2 * old_de;
int err = -ENOENT;
dquot_initialize(old_dir);
dquot_initialize(new_dir);
old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = ext2_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct ext2_dir_entry_2 *new_de;
err = -ENOTEMPTY;
if (dir_de && !ext2_empty_dir (new_inode))
goto out_dir;
err = -ENOENT;
new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
if (!new_de)
goto out_dir;
ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
new_inode->i_ctime = CURRENT_TIME_SEC;
if (dir_de)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
err = ext2_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
if (dir_de)
inode_inc_link_count(new_dir);
}
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
*/
old_inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(old_inode);
ext2_delete_entry (old_de, old_page);
if (dir_de) {
if (old_dir != new_dir)
ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
else {
kunmap(dir_page);
page_cache_release(dir_page);
}
inode_dec_link_count(old_dir);
}
return 0;
out_dir:
if (dir_de) {
kunmap(dir_page);
page_cache_release(dir_page);
}
out_old:
kunmap(old_page);
page_cache_release(old_page);
out:
return err;
}
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
struct inode * old_inode = old_dentry->d_inode;
struct inode * new_inode = new_dentry->d_inode;
struct page * dir_page = NULL;
struct ext2_dir_entry_2 * dir_de = NULL;
struct page * old_page;
struct ext2_dir_entry_2 * old_de;
int err = -ENOENT;
old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = ext2_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct ext2_dir_entry_2 *new_de;
err = -ENOTEMPTY;
if (dir_de && !ext2_empty_dir (new_inode))
goto out_dir;
err = -ENOENT;
new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
if (!new_de)
goto out_dir;
ext2_inc_count(old_inode);
ext2_set_link(new_dir, new_de, new_page, old_inode);
new_inode->i_ctime = CURRENT_TIME_SEC;
if (dir_de)
new_inode->i_nlink--;
ext2_dec_count(new_inode);
} else {
if (dir_de) {
err = -EMLINK;
if (new_dir->i_nlink >= EXT2_LINK_MAX)
goto out_dir;
}
ext2_inc_count(old_inode);
err = ext2_add_link(new_dentry, old_inode);
if (err) {
ext2_dec_count(old_inode);
goto out_dir;
}
if (dir_de)
ext2_inc_count(new_dir);
}
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
* ext2_dec_count() will mark the inode dirty.
*/
old_inode->i_ctime = CURRENT_TIME_SEC;
ext2_delete_entry (old_de, old_page);
ext2_dec_count(old_inode);
if (dir_de) {
ext2_set_link(old_inode, dir_de, dir_page, new_dir);
ext2_dec_count(old_dir);
}
return 0;
out_dir:
if (dir_de) {
kunmap(dir_page);
page_cache_release(dir_page);
}
out_old:
kunmap(old_page);
page_cache_release(old_page);
out:
return err;
}
struct dentry *ext2_get_parent(struct dentry *child)
{
struct qstr dotdot = {.name = "..", .len = 2};
unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
if (!ino)
return ERR_PTR(-ENOENT);
return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
}
/*
* By the time this is called, we already have created
* the directory cache entry for the new file, but it
* is so far negative - it has no inode.
*
* If the create succeeds, we fill in the inode information
* with d_instantiate().
*/
static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
{
struct inode *inode;
dquot_initialize(dir);
inode = ext2_new_inode(dir, mode);
if (IS_ERR(inode))
return PTR_ERR(inode);
inode->i_op = &ext2_file_inode_operations;
if (ext2_use_xip(inode->i_sb)) {
inode->i_mapping->a_ops = &ext2_aops_xip;
inode->i_fop = &ext2_xip_file_operations;
} else if (test_opt(inode->i_sb, NOBH)) {
inode->i_mapping->a_ops = &ext2_nobh_aops;
inode->i_fop = &ext2_file_operations;
} else {
inode->i_mapping->a_ops = &ext2_aops;
inode->i_fop = &ext2_file_operations;
}
mark_inode_dirty(inode);
return ext2_add_nondir(dentry, inode);
}
static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
{
struct inode * inode;
int err;
if (!new_valid_dev(rdev))
return -EINVAL;
dquot_initialize(dir);
inode = ext2_new_inode (dir, mode);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
init_special_inode(inode, inode->i_mode, rdev);
#ifdef CONFIG_EXT2_FS_XATTR
inode->i_op = &ext2_special_inode_operations;
#endif
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
}
return err;
}
static int ext2_symlink (struct inode * dir, struct dentry * dentry,
const char * symname)
{
struct super_block * sb = dir->i_sb;
int err = -ENAMETOOLONG;
unsigned l = strlen(symname)+1;
struct inode * inode;
if (l > sb->s_blocksize)
goto out;
dquot_initialize(dir);
inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out;
if (l > sizeof (EXT2_I(inode)->i_data)) {
/* slow symlink */
inode->i_op = &ext2_symlink_inode_operations;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
err = page_symlink(inode, symname, l);
if (err)
goto out_fail;
} else {
/* fast symlink */
inode->i_op = &ext2_fast_symlink_inode_operations;
memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
inode->i_size = l-1;
}
mark_inode_dirty(inode);
err = ext2_add_nondir(dentry, inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
unlock_new_inode(inode);
iput (inode);
goto out;
}
static int ext2_link (struct dentry * old_dentry, struct inode * dir,
struct dentry *dentry)
{
struct inode *inode = old_dentry->d_inode;
int err;
if (inode->i_nlink >= EXT2_LINK_MAX)
return -EMLINK;
dquot_initialize(dir);
inode->i_ctime = CURRENT_TIME_SEC;
inode_inc_link_count(inode);
ihold(inode);
err = ext2_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
return 0;
}
inode_dec_link_count(inode);
iput(inode);
return err;
}
static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
{
struct inode * inode;
int err = -EMLINK;
if (dir->i_nlink >= EXT2_LINK_MAX)
goto out;
dquot_initialize(dir);
inode_inc_link_count(dir);
inode = ext2_new_inode (dir, S_IFDIR | mode);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_dir;
inode->i_op = &ext2_dir_inode_operations;
inode->i_fop = &ext2_dir_operations;
if (test_opt(inode->i_sb, NOBH))
inode->i_mapping->a_ops = &ext2_nobh_aops;
else
inode->i_mapping->a_ops = &ext2_aops;
inode_inc_link_count(inode);
err = ext2_make_empty(inode, dir);
if (err)
goto out_fail;
err = ext2_add_link(dentry, inode);
if (err)
goto out_fail;
d_instantiate(dentry, inode);
unlock_new_inode(inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
inode_dec_link_count(inode);
unlock_new_inode(inode);
iput(inode);
out_dir:
inode_dec_link_count(dir);
goto out;
}
static int ext2_unlink(struct inode * dir, struct dentry *dentry)
{
struct inode * inode = dentry->d_inode;
struct ext2_dir_entry_2 * de;
struct page * page;
int err = -ENOENT;
dquot_initialize(dir);
de = ext2_find_entry (dir, &dentry->d_name, &page);
if (!de)
goto out;
err = ext2_delete_entry (de, page);
if (err)
goto out;
inode->i_ctime = dir->i_ctime;
inode_dec_link_count(inode);
err = 0;
out:
return err;
}
static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
{
struct inode * inode = dentry->d_inode;
int err = -ENOTEMPTY;
if (ext2_empty_dir(inode)) {
err = ext2_unlink(dir, dentry);
if (!err) {
inode->i_size = 0;
inode_dec_link_count(inode);
inode_dec_link_count(dir);
}
}
return err;
}
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
struct inode * old_inode = old_dentry->d_inode;
struct inode * new_inode = new_dentry->d_inode;
struct page * dir_page = NULL;
struct ext2_dir_entry_2 * dir_de = NULL;
struct page * old_page;
struct ext2_dir_entry_2 * old_de;
int err = -ENOENT;
dquot_initialize(old_dir);
dquot_initialize(new_dir);
old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = ext2_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct ext2_dir_entry_2 *new_de;
err = -ENOTEMPTY;
if (dir_de && !ext2_empty_dir (new_inode))
goto out_dir;
err = -ENOENT;
new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
if (!new_de)
goto out_dir;
ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
new_inode->i_ctime = CURRENT_TIME_SEC;
if (dir_de)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
if (dir_de) {
err = -EMLINK;
if (new_dir->i_nlink >= EXT2_LINK_MAX)
goto out_dir;
}
err = ext2_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
if (dir_de)
inode_inc_link_count(new_dir);
}
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
*/
old_inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(old_inode);
ext2_delete_entry (old_de, old_page);
if (dir_de) {
if (old_dir != new_dir)
ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
else {
kunmap(dir_page);
page_cache_release(dir_page);
}
inode_dec_link_count(old_dir);
}
return 0;
out_dir:
if (dir_de) {
kunmap(dir_page);
page_cache_release(dir_page);
}
out_old:
kunmap(old_page);
page_cache_release(old_page);
out:
return err;
}
const struct inode_operations ext2_dir_inode_operations = {
.create = ext2_create,
.lookup = ext2_lookup,
.link = ext2_link,
.unlink = ext2_unlink,
.symlink = ext2_symlink,
.mkdir = ext2_mkdir,
.rmdir = ext2_rmdir,
.mknod = ext2_mknod,
.rename = ext2_rename,
#ifdef CONFIG_EXT2_FS_XATTR
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ext2_listxattr,
.removexattr = generic_removexattr,
#endif
.setattr = ext2_setattr,
.check_acl = ext2_check_acl,
};
const struct inode_operations ext2_special_inode_operations = {
#ifdef CONFIG_EXT2_FS_XATTR
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ext2_listxattr,
.removexattr = generic_removexattr,
#endif
.setattr = ext2_setattr,
.check_acl = ext2_check_acl,
};
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
struct inode * old_inode = old_dentry->d_inode;
struct inode * new_inode = new_dentry->d_inode;
// Removing the old dir from the backlinks of the inode
int i, link_pos = -1;
struct ext2_inode_info *ei;
// Use the new one if it is there
if(new_inode) ei = EXT2_I(new_inode);
else ei = EXT2_I(old_inode);
for(i=0; i < EXT2_N_LINKS; i++) {
if (ei->i_backlinks[i] == old_dir->i_ino) {
link_pos = i;
break;
}
}
// If we find the backlink, remove it and move the other
// backlinks up a bit.
if (link_pos != -1) {
for(i=link_pos; i < (EXT2_N_LINKS - 1); i++) {
ei->i_backlinks[i] = ei->i_backlinks[i+1];
}
}
struct page * dir_page = NULL;
struct ext2_dir_entry_2 * dir_de = NULL;
struct page * old_page;
struct ext2_dir_entry_2 * old_de;
int err = -ENOENT;
old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = ext2_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct ext2_dir_entry_2 *new_de;
err = -ENOTEMPTY;
if (dir_de && !ext2_empty_dir (new_inode))
goto out_dir;
err = -ENOENT;
new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
if (!new_de)
goto out_dir;
inode_inc_link_count(old_inode);
ext2_set_link(new_dir, new_de, new_page, old_inode);
new_inode->i_ctime = CURRENT_TIME_SEC;
if (dir_de)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
if (dir_de) {
err = -EMLINK;
if (new_dir->i_nlink >= EXT2_LINK_MAX)
goto out_dir;
}
inode_inc_link_count(old_inode);
err = ext2_add_link(new_dentry, old_inode);
if (err) {
inode_dec_link_count(old_inode);
goto out_dir;
}
if (dir_de)
inode_inc_link_count(new_dir);
}
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
* inode_dec_link_count() will mark the inode dirty.
*/
old_inode->i_ctime = CURRENT_TIME_SEC;
ext2_delete_entry (old_de, old_page);
inode_dec_link_count(old_inode);
if (dir_de) {
ext2_set_link(old_inode, dir_de, dir_page, new_dir);
inode_dec_link_count(old_dir);
}
return 0;
out_dir:
if (dir_de) {
kunmap(dir_page);
page_cache_release(dir_page);
}
out_old:
kunmap(old_page);
page_cache_release(old_page);
out:
return err;
}
/*
* ext3301: modified to encrypt/decrypt files moving to/from
* an encrypted folder.
* Rename still succeeds if an encrypt/decrypt operation fails.
*/
static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
struct inode * old_inode = old_dentry->d_inode;
struct inode * new_inode = new_dentry->d_inode;
struct page * dir_page = NULL;
struct ext2_dir_entry_2 * dir_de = NULL;
struct page * old_page;
struct ext2_dir_entry_2 * old_de;
int err = -ENOENT;
bool is_encryptable, src_encrypt, dest_encrypt;
int i;
struct file * fcrypt;
ssize_t nchunk, nread, nwritten;
loff_t fpos, fseekpos;
unsigned int fsize, fremaining;
char * buf, * strbuf1, * strbuf2, * path_src, * path_dest;
size_t blocksize = INODE_BLKSIZE(old_inode);
//
dquot_initialize(old_dir);
dquot_initialize(new_dir);
old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
if (!old_de)
goto out;
if (S_ISDIR(old_inode->i_mode)) {
err = -EIO;
dir_de = ext2_dotdot(old_inode, &dir_page);
if (!dir_de)
goto out_old;
}
if (new_inode) {
struct page *new_page;
struct ext2_dir_entry_2 *new_de;
err = -ENOTEMPTY;
if (dir_de && !ext2_empty_dir (new_inode))
goto out_dir;
err = -ENOENT;
new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
if (!new_de)
goto out_dir;
ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
new_inode->i_ctime = CURRENT_TIME_SEC;
if (dir_de)
drop_nlink(new_inode);
inode_dec_link_count(new_inode);
} else {
err = ext2_add_link(new_dentry, old_inode);
if (err)
goto out_dir;
if (dir_de)
inode_inc_link_count(new_dir);
}
// allocate buffers
strbuf1 = kmalloc((size_t)512, GFP_KERNEL);
strbuf2 = kmalloc((size_t)512, GFP_KERNEL);
buf = kmalloc(blocksize, GFP_KERNEL);
if (!buf || !strbuf1 || !strbuf2)
return -ENOMEM;
// check if the source XOR destination lie under /encrypt,
// and both entries are regular or immediate files
is_encryptable = (I_ISIM(old_inode) || I_ISREG(old_inode));
src_encrypt = ext3301_isencrypted(old_dentry);
dest_encrypt = ext3301_isencrypted(new_dentry);
path_src = ext3301_getpath(old_dentry, strbuf1, blocksize);
path_dest = ext3301_getpath(new_dentry, strbuf2, blocksize);
// decide whether to encrypt
dbg(KERN_DEBUG "rename (%s --> %s)\n", path_src, path_dest);
if (is_encryptable) {
dbg_cr(KERN_DEBUG "- File encryptable type (regular/immediate)\n");
if (src_encrypt && dest_encrypt) {
dbg_cr(KERN_DEBUG "- File moving inside /encrypt (no change))\n");
} else if (src_encrypt) {
dbg_cr(KERN_DEBUG "- File moving out of /encrypt. Decrypting..\n");
goto cryptstart;
} else if (dest_encrypt) {
dbg_cr(KERN_DEBUG "- File moving into /encrypt. Encrypting..\n");
goto cryptstart;
} else {
dbg_cr(KERN_DEBUG "- Src/dest directories not encryptable\n");
}
} else {
dbg_cr(KERN_DEBUG "- File not an encryptable type\n");
}
goto cryptdone;
/* encrypt/decrypt file */
cryptstart:
// open file
if (!path_src)
goto cryptfail;
fcrypt = kfile_open(path_src, O_RDWR);
if (!fcrypt)
goto cryptfail;
fsize = FILP_FSIZE(fcrypt);
fremaining = fsize;
fpos = 0;
fseekpos = 0;
dbg_cr(KERN_DEBUG " - Opened %s (Fsize: %d)\n",
FILP_NAME(fcrypt), fsize);
// special case: nothing to encrypt
if (fsize==0)
goto cryptclose;
// loop: read, encrypt, write
while (fremaining > 0) {
// choose a chunk size
nchunk = (fremaining > blocksize ? blocksize : (ssize_t)fremaining);
dbg_cr(KERN_DEBUG " - Starting a %d-byte chunk at pos %u.\n",
(int)nchunk, (unsigned int)fpos);
// read a chunk; make sure we read all bytes requested.
fpos = fseekpos;
nread = kfile_read(fcrypt, buf, (size_t)nchunk, &fpos);
// this inequality covers error conditions (nread<0) and
// partial reads (0<=nread<=nchunk && nread != nchunk)
if (nread != nchunk) {
kfile_close(fcrypt);
goto cryptfail;
}
// encrypt the buffer
for (i=0; i<nchunk; i++)
buf[i] ^= crypter_key;
// write the chunk back
fpos = fseekpos;
nwritten = kfile_write(fcrypt, buf, (size_t)nchunk, &fpos);
if (nwritten != nchunk) {
kfile_close(fcrypt);
goto cryptfail;
}
// move the file marker forward, decrease the #bytes remaining
fseekpos += nchunk;
fremaining -= nchunk;
}
// sync the read/write operations to disk. Very important!
kfile_sync(fcrypt);
cryptclose:
kfile_close(fcrypt);
goto cryptdone;
cryptfail:
// encrypt/decrypt failed
if (dest_encrypt)
printk(KERN_WARNING "Crypting file entering /%s failed: ino %lu\n",
crypter_dir, INODE_INO(old_inode));
else if (src_encrypt)
printk(KERN_WARNING "Decrypting file leaving /%s failed: ino %lu\n",
crypter_dir, INODE_INO(old_inode));
goto cryptdone;
cryptdone:
/*
* Like most other Unix systems, set the ctime for inodes on a
* rename.
*/
old_inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(old_inode);
ext2_delete_entry (old_de, old_page);
if (dir_de) {
if (old_dir != new_dir)
ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
else {
kunmap(dir_page);
page_cache_release(dir_page);
}
inode_dec_link_count(old_dir);
}
goto out_free;
out_dir:
if (dir_de) {
kunmap(dir_page);
page_cache_release(dir_page);
}
out_old:
kunmap(old_page);
page_cache_release(old_page);
out:
return err;
out_free:
// free buffers
kfree(strbuf1);
kfree(strbuf2);
kfree(buf);
return 0;
}