/* This function replicates the directory structure upto given dentry
* in the bindex branch. */
struct dentry *create_parents_named(struct inode *dir, struct dentry *dentry,
const char *name, int bindex)
{
int err;
struct dentry *child_dentry;
struct dentry *parent_dentry;
struct dentry *hidden_parent_dentry = NULL;
struct dentry *hidden_dentry = NULL;
const char *childname;
unsigned int childnamelen;
int old_kmalloc_size;
int kmalloc_size;
int num_dentry;
int count;
int old_bstart;
int old_bend;
struct dentry **path = NULL;
struct dentry **tmp_path;
print_entry_location();
verify_locked(dentry);
/* There is no sense allocating any less than the minimum. */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
kmalloc_size = malloc_sizes[0].cs_size;
#else
kmalloc_size = 32;
#endif
num_dentry = kmalloc_size / sizeof(struct dentry *);
if ((err = is_robranch_super(dir->i_sb, bindex))) {
hidden_dentry = ERR_PTR(err);
goto out;
}
fist_print_dentry("IN: create_parents_named", dentry);
fist_dprint(8, "name = %s\n", name);
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
path = (struct dentry **)KMALLOC(kmalloc_size, GFP_KERNEL);
memset(path, 0, kmalloc_size);
/* assume the negative dentry of unionfs as the parent dentry */
parent_dentry = dentry;
count = 0;
/* This loop finds the first parent that exists in the given branch.
* We start building the directory structure from there. At the end
* of the loop, the following should hold:
* child_dentry is the first nonexistent child
* parent_dentry is the first existent parent
* path[0] is the = deepest child
* path[count] is the first child to create
*/
do {
child_dentry = parent_dentry;
/* find the parent directory dentry in unionfs */
parent_dentry = child_dentry->d_parent;
lock_dentry(parent_dentry);
/* find out the hidden_parent_dentry in the given branch */
hidden_parent_dentry = dtohd_index(parent_dentry, bindex);
/* store the child dentry */
path[count++] = child_dentry;
if (count == num_dentry) {
old_kmalloc_size = kmalloc_size;
kmalloc_size *= 2;
num_dentry = kmalloc_size / sizeof(struct dentry *);
tmp_path =
(struct dentry **)KMALLOC(kmalloc_size, GFP_KERNEL);
if (!tmp_path) {
hidden_dentry = ERR_PTR(-ENOMEM);
goto out;
}
memset(tmp_path, 0, kmalloc_size);
memcpy(tmp_path, path, old_kmalloc_size);
KFREE(path);
path = tmp_path;
tmp_path = NULL;
}
} while (!hidden_parent_dentry);
count--;
/* This is basically while(child_dentry != dentry). This loop is
* horrible to follow and should be replaced with cleaner code. */
while (1) {
PASSERT(child_dentry);
PASSERT(parent_dentry);
PASSERT(parent_dentry->d_inode);
// get hidden parent dir in the current branch
hidden_parent_dentry = dtohd_index(parent_dentry, bindex);
unlock_dentry(parent_dentry);
PASSERT(hidden_parent_dentry);
PASSERT(hidden_parent_dentry->d_inode);
// init the values to lookup
childname = child_dentry->d_name.name;
childnamelen = child_dentry->d_name.len;
if (child_dentry != dentry) {
// lookup child in the underlying file system
hidden_dentry =
LOOKUP_ONE_LEN(childname, hidden_parent_dentry,
childnamelen);
if (IS_ERR(hidden_dentry))
goto out;
} else {
int loop_start;
int loop_end;
int new_bstart = -1;
int new_bend = -1;
int i;
/* is the name a whiteout of the childname ? */
//lookup the whiteout child in the underlying file system
hidden_dentry =
LOOKUP_ONE_LEN(name, hidden_parent_dentry,
strlen(name));
if (IS_ERR(hidden_dentry))
goto out;
/* Replace the current dentry (if any) with the new one. */
DPUT(dtohd_index(dentry, bindex));
set_dtohd_index(dentry, bindex, hidden_dentry);
loop_start =
(old_bstart < bindex) ? old_bstart : bindex;
loop_end = (old_bend > bindex) ? old_bend : bindex;
/* This loop sets the bstart and bend for the new
* dentry by traversing from left to right.
* It also dputs all negative dentries except
* bindex (the newly looked dentry
*/
for (i = loop_start; i <= loop_end; i++) {
if (!dtohd_index(dentry, i))
continue;
if (i == bindex) {
new_bend = i;
if (new_bstart < 0)
new_bstart = i;
continue;
}
if (!dtohd_index(dentry, i)->d_inode) {
DPUT(dtohd_index(dentry, i));
set_dtohd_index(dentry, i, NULL);
} else {
if (new_bstart < 0)
new_bstart = i;
new_bend = i;
}
}
if (new_bstart < 0)
new_bstart = bindex;
if (new_bend < 0)
new_bend = bindex;
set_dbstart(dentry, new_bstart);
set_dbend(dentry, new_bend);
break;
}
if (hidden_dentry->d_inode) {
/* since this already exists we dput to avoid
* multiple references on the same dentry */
DPUT(hidden_dentry);
} else {
uid_t saved_uid = current->fsuid;
gid_t saved_gid = current->fsgid;
/* its a negative dentry, create a new dir */
hidden_parent_dentry = lock_parent(hidden_dentry);
current->fsuid = hidden_parent_dentry->d_inode->i_uid;
current->fsgid = hidden_parent_dentry->d_inode->i_gid;
err = vfs_mkdir(hidden_parent_dentry->d_inode,
hidden_dentry, S_IRWXUGO);
current->fsuid = saved_uid;
current->fsgid = saved_gid;
unlock_dir(hidden_parent_dentry);
if (err || !hidden_dentry->d_inode) {
DPUT(hidden_dentry);
hidden_dentry = ERR_PTR(err);
goto out;
}
err =
copyup_permissions(dir->i_sb, child_dentry,
hidden_dentry);
if (err) {
DPUT(hidden_dentry);
hidden_dentry = ERR_PTR(err);
goto out;
}
set_itohi_index(child_dentry->d_inode, bindex,
igrab(hidden_dentry->d_inode));
if (ibstart(child_dentry->d_inode) > bindex)
ibstart(child_dentry->d_inode) = bindex;
if (ibend(child_dentry->d_inode) < bindex)
ibend(child_dentry->d_inode) = bindex;
set_dtohd_index(child_dentry, bindex, hidden_dentry);
if (dbstart(child_dentry) > bindex)
set_dbstart(child_dentry, bindex);
if (dbend(child_dentry) < bindex)
set_dbend(child_dentry, bindex);
}
parent_dentry = child_dentry;
child_dentry = path[--count];
}
out:
KFREE(path);
fist_print_dentry("OUT: create_parents_named", dentry);
print_exit_pointer(hidden_dentry);
return hidden_dentry;
}
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;
}
/*
* This function replicates the directory structure up-to given dentry
* in the bindex branch.
*/
struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
const char *name, int bindex)
{
int err;
struct dentry *child_dentry;
struct dentry *parent_dentry;
struct dentry *lower_parent_dentry = NULL;
struct dentry *lower_dentry = NULL;
const char *childname;
unsigned int childnamelen;
int nr_dentry;
int count = 0;
int old_bstart;
int old_bend;
struct dentry **path = NULL;
struct super_block *sb;
verify_locked(dentry);
err = is_robranch_super(dir->i_sb, bindex);
if (err) {
lower_dentry = ERR_PTR(err);
goto out;
}
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
lower_dentry = ERR_PTR(-ENOMEM);
/* There is no sense allocating any less than the minimum. */
nr_dentry = 1;
path = kmalloc(nr_dentry * sizeof(struct dentry *), GFP_KERNEL);
if (unlikely(!path))
goto out;
/* assume the negative dentry of unionfs as the parent dentry */
parent_dentry = dentry;
/*
* This loop finds the first parent that exists in the given branch.
* We start building the directory structure from there. At the end
* of the loop, the following should hold:
* - child_dentry is the first nonexistent child
* - parent_dentry is the first existent parent
* - path[0] is the = deepest child
* - path[count] is the first child to create
*/
do {
child_dentry = parent_dentry;
/* find the parent directory dentry in unionfs */
parent_dentry = dget_parent(child_dentry);
/* find out the lower_parent_dentry in the given branch */
lower_parent_dentry =
unionfs_lower_dentry_idx(parent_dentry, bindex);
/* grow path table */
if (count == nr_dentry) {
void *p;
nr_dentry *= 2;
p = krealloc(path, nr_dentry * sizeof(struct dentry *),
GFP_KERNEL);
if (unlikely(!p)) {
lower_dentry = ERR_PTR(-ENOMEM);
goto out;
}
path = p;
}
/* store the child dentry */
path[count++] = child_dentry;
} while (!lower_parent_dentry);
count--;
sb = dentry->d_sb;
/*
* This code goes between the begin/end labels and basically
* emulates a while(child_dentry != dentry), only cleaner and
* shorter than what would be a much longer while loop.
*/
begin:
/* get lower parent dir in the current branch */
lower_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
dput(parent_dentry);
/* init the values to lookup */
childname = child_dentry->d_name.name;
childnamelen = child_dentry->d_name.len;
if (child_dentry != dentry) {
/* lookup child in the underlying file system */
lower_dentry = lookup_one_len(childname, lower_parent_dentry,
childnamelen);
if (IS_ERR(lower_dentry))
goto out;
} else {
/*
* Is the name a whiteout of the child name ? lookup the
* whiteout child in the underlying file system
*/
lower_dentry = lookup_one_len(name, lower_parent_dentry,
strlen(name));
if (IS_ERR(lower_dentry))
goto out;
/* Replace the current dentry (if any) with the new one */
dput(unionfs_lower_dentry_idx(dentry, bindex));
unionfs_set_lower_dentry_idx(dentry, bindex,
lower_dentry);
__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
goto out;
}
if (lower_dentry->d_inode) {
/*
* since this already exists we dput to avoid
* multiple references on the same dentry
*/
dput(lower_dentry);
} else {
struct sioq_args args;
/* it's a negative dentry, create a new dir */
lower_parent_dentry = lock_parent(lower_dentry);
args.mkdir.parent = lower_parent_dentry->d_inode;
args.mkdir.dentry = lower_dentry;
args.mkdir.mode = child_dentry->d_inode->i_mode;
run_sioq(__unionfs_mkdir, &args);
err = args.err;
if (!err)
err = copyup_permissions(dir->i_sb, child_dentry,
lower_dentry);
unlock_dir(lower_parent_dentry);
if (err) {
dput(lower_dentry);
lower_dentry = ERR_PTR(err);
goto out;
}
}
__set_inode(child_dentry, lower_dentry, bindex);
__set_dentry(child_dentry, lower_dentry, bindex);
/*
* update times of this dentry, but also the parent, because if
* we changed, the parent may have changed too.
*/
fsstack_copy_attr_times(parent_dentry->d_inode,
lower_parent_dentry->d_inode);
unionfs_copy_attr_times(child_dentry->d_inode);
parent_dentry = child_dentry;
child_dentry = path[--count];
goto begin;
out:
/* cleanup any leftover locks from the do/while loop above */
if (IS_ERR(lower_dentry))
while (count)
dput(path[count--]);
kfree(path);
return lower_dentry;
}
/*
* Copy up a dentry to a file of specified name.
*
* @dir: used to pull the ->i_sb to access other branches
* @dentry: the non-negative dentry whose lower_inode we should copy
* @bstart: the branch of the lower_inode to copy from
* @new_bindex: the branch to create the new file in
* @name: the name of the file to create
* @namelen: length of @name
* @copyup_file: the "struct file" to return (optional)
* @len: how many bytes to copy-up?
*/
int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart,
int new_bindex, const char *name, int namelen,
struct file **copyup_file, loff_t len)
{
struct dentry *new_lower_dentry;
struct dentry *old_lower_dentry = NULL;
struct super_block *sb;
int err = 0;
int old_bindex;
int old_bstart;
int old_bend;
struct dentry *new_lower_parent_dentry = NULL;
mm_segment_t oldfs;
char *symbuf = NULL;
verify_locked(dentry);
old_bindex = bstart;
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
BUG_ON(new_bindex < 0);
BUG_ON(new_bindex >= old_bindex);
sb = dir->i_sb;
err = is_robranch_super(sb, new_bindex);
if (err)
goto out;
/* Create the directory structure above this dentry. */
new_lower_dentry = create_parents(dir, dentry, name, new_bindex);
if (IS_ERR(new_lower_dentry)) {
err = PTR_ERR(new_lower_dentry);
goto out;
}
old_lower_dentry = unionfs_lower_dentry_idx(dentry, old_bindex);
/* we conditionally dput this old_lower_dentry at end of function */
dget(old_lower_dentry);
/* For symlinks, we must read the link before we lock the directory. */
if (S_ISLNK(old_lower_dentry->d_inode->i_mode)) {
symbuf = kmalloc(PATH_MAX, GFP_KERNEL);
if (unlikely(!symbuf)) {
__clear(dentry, old_lower_dentry,
old_bstart, old_bend,
new_lower_dentry, new_bindex);
err = -ENOMEM;
goto out_free;
}
oldfs = get_fs();
set_fs(KERNEL_DS);
err = old_lower_dentry->d_inode->i_op->readlink(
old_lower_dentry,
(char __user *)symbuf,
PATH_MAX);
set_fs(oldfs);
if (err < 0) {
__clear(dentry, old_lower_dentry,
old_bstart, old_bend,
new_lower_dentry, new_bindex);
goto out_free;
}
symbuf[err] = '\0';
}
/* Now we lock the parent, and create the object in the new branch. */
new_lower_parent_dentry = lock_parent(new_lower_dentry);
/* create the new inode */
err = __copyup_ndentry(old_lower_dentry, new_lower_dentry,
new_lower_parent_dentry, symbuf);
if (err) {
__clear(dentry, old_lower_dentry,
old_bstart, old_bend,
new_lower_dentry, new_bindex);
goto out_unlock;
}
/* We actually copyup the file here. */
if (S_ISREG(old_lower_dentry->d_inode->i_mode))
err = __copyup_reg_data(dentry, new_lower_dentry, new_bindex,
old_lower_dentry, old_bindex,
copyup_file, len);
if (err)
goto out_unlink;
/* Set permissions. */
err = copyup_permissions(sb, old_lower_dentry, new_lower_dentry);
if (err)
goto out_unlink;
#ifdef CONFIG_UNION_FS_XATTR
/* Selinux uses extended attributes for permissions. */
err = copyup_xattrs(old_lower_dentry, new_lower_dentry);
if (err)
goto out_unlink;
#endif /* CONFIG_UNION_FS_XATTR */
/* do not allow files getting deleted to be re-interposed */
if (!d_deleted(dentry))
unionfs_reinterpose(dentry);
goto out_unlock;
out_unlink:
/*
* copyup failed, because we possibly ran out of space or
* quota, or something else happened so let's unlink; we don't
* really care about the return value of vfs_unlink
*/
vfs_unlink(new_lower_parent_dentry->d_inode, new_lower_dentry);
if (copyup_file) {
/* need to close the file */
fput(*copyup_file);
branchput(sb, new_bindex);
}
/*
* TODO: should we reset the error to something like -EIO?
*
* If we don't reset, the user may get some nonsensical errors, but
* on the other hand, if we reset to EIO, we guarantee that the user
* will get a "confusing" error message.
*/
out_unlock:
unlock_dir(new_lower_parent_dentry);
out_free:
/*
* If old_lower_dentry was not a file, then we need to dput it. If
* it was a file, then it was already dput indirectly by other
* functions we call above which operate on regular files.
*/
if (old_lower_dentry && old_lower_dentry->d_inode &&
!S_ISREG(old_lower_dentry->d_inode->i_mode))
dput(old_lower_dentry);
kfree(symbuf);
if (err) {
/*
* if directory creation succeeded, but inode copyup failed,
* then purge new dentries.
*/
if (dbstart(dentry) < old_bstart &&
ibstart(dentry->d_inode) > dbstart(dentry))
__clear(dentry, NULL, old_bstart, old_bend,
unionfs_lower_dentry(dentry), dbstart(dentry));
goto out;
}
if (!S_ISDIR(dentry->d_inode->i_mode)) {
unionfs_postcopyup_release(dentry);
if (!unionfs_lower_inode(dentry->d_inode)) {
/*
* If we got here, then we copied up to an
* unlinked-open file, whose name is .unionfsXXXXX.
*/
struct inode *inode = new_lower_dentry->d_inode;
atomic_inc(&inode->i_count);
unionfs_set_lower_inode_idx(dentry->d_inode,
ibstart(dentry->d_inode),
inode);
}
}
unionfs_postcopyup_setmnt(dentry);
/* sync inode times from copied-up inode to our inode */
unionfs_copy_attr_times(dentry->d_inode);
unionfs_check_inode(dir);
unionfs_check_dentry(dentry);
out:
return err;
}
/* This function replicates the directory structure upto given dentry
* in the bindex branch.
*/
static struct dentry *create_parents_named(struct inode *dir,
struct dentry *dentry,
const char *name, int bindex)
{
int err;
struct dentry *child_dentry;
struct dentry *parent_dentry;
struct dentry *hidden_parent_dentry = NULL;
struct dentry *hidden_dentry = NULL;
const char *childname;
unsigned int childnamelen;
int old_kmalloc_size;
int kmalloc_size;
int num_dentry;
int count;
int old_bstart;
int old_bend;
struct dentry **path = NULL;
struct dentry **tmp_path;
struct super_block *sb;
verify_locked(dentry);
/* There is no sense allocating any less than the minimum. */
kmalloc_size = malloc_sizes[0].cs_size;
num_dentry = kmalloc_size / sizeof(struct dentry *);
if ((err = is_robranch_super(dir->i_sb, bindex))) {
hidden_dentry = ERR_PTR(err);
goto out;
}
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
hidden_dentry = ERR_PTR(-ENOMEM);
path = kzalloc(kmalloc_size, GFP_KERNEL);
if (!path)
goto out;
/* assume the negative dentry of unionfs as the parent dentry */
parent_dentry = dentry;
count = 0;
/* This loop finds the first parent that exists in the given branch.
* We start building the directory structure from there. At the end
* of the loop, the following should hold:
* - child_dentry is the first nonexistent child
* - parent_dentry is the first existent parent
* - path[0] is the = deepest child
* - path[count] is the first child to create
*/
do {
child_dentry = parent_dentry;
/* find the parent directory dentry in unionfs */
parent_dentry = child_dentry->d_parent;
unionfs_lock_dentry(parent_dentry);
/* find out the hidden_parent_dentry in the given branch */
hidden_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
/* store the child dentry */
path[count++] = child_dentry;
/* grow path table */
if (count == num_dentry) {
old_kmalloc_size = kmalloc_size;
kmalloc_size *= 2;
num_dentry = kmalloc_size / sizeof(struct dentry *);
tmp_path = kzalloc(kmalloc_size, GFP_KERNEL);
if (!tmp_path) {
hidden_dentry = ERR_PTR(-ENOMEM);
goto out;
}
memcpy(tmp_path, path, old_kmalloc_size);
kfree(path);
path = tmp_path;
tmp_path = NULL;
}
} while (!hidden_parent_dentry);
count--;
sb = dentry->d_sb;
/* This is basically while(child_dentry != dentry). This loop is
* horrible to follow and should be replaced with cleaner code.
*/
while (1) {
/* get hidden parent dir in the current branch */
hidden_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
unionfs_unlock_dentry(parent_dentry);
/* init the values to lookup */
childname = child_dentry->d_name.name;
childnamelen = child_dentry->d_name.len;
if (child_dentry != dentry) {
/* lookup child in the underlying file system */
hidden_dentry =
lookup_one_len(childname, hidden_parent_dentry,
childnamelen);
if (IS_ERR(hidden_dentry))
goto out;
} else {
/* is the name a whiteout of the childname ?
* lookup the whiteout child in the underlying file system
*/
hidden_dentry =
lookup_one_len(name, hidden_parent_dentry,
strlen(name));
if (IS_ERR(hidden_dentry))
goto out;
/* Replace the current dentry (if any) with the new one. */
dput(unionfs_lower_dentry_idx(dentry, bindex));
unionfs_set_lower_dentry_idx(dentry, bindex, hidden_dentry);
__cleanup_dentry(dentry, bindex, old_bstart, old_bend);
break;
}
if (hidden_dentry->d_inode) {
/* since this already exists we dput to avoid
* multiple references on the same dentry
*/
dput(hidden_dentry);
} else {
struct sioq_args args;
/* its a negative dentry, create a new dir */
hidden_parent_dentry = lock_parent(hidden_dentry);
args.mkdir.parent = hidden_parent_dentry->d_inode;
args.mkdir.dentry = hidden_dentry;
args.mkdir.mode = child_dentry->d_inode->i_mode;
run_sioq(__unionfs_mkdir, &args);
err = args.err;
if (!err)
err = copyup_permissions(dir->i_sb,
child_dentry, hidden_dentry);
unlock_dir(hidden_parent_dentry);
if (err) {
dput(hidden_dentry);
hidden_dentry = ERR_PTR(err);
goto out;
}
}
__set_inode(child_dentry, hidden_dentry, bindex);
__set_dentry(child_dentry, hidden_dentry, bindex);
parent_dentry = child_dentry;
child_dentry = path[--count];
}
out:
kfree(path);
return hidden_dentry;
}
/* copy up a dentry to a file of specified name */
static int copyup_named_dentry(struct inode *dir, struct dentry *dentry,
int bstart, int new_bindex, const char *name,
int namelen, struct file **copyup_file,
loff_t len)
{
struct dentry *new_hidden_dentry;
struct dentry *old_hidden_dentry = NULL;
struct super_block *sb;
int err = 0;
int old_bindex;
int old_bstart;
int old_bend;
struct dentry *new_hidden_parent_dentry = NULL;
mm_segment_t oldfs;
char *symbuf = NULL;
verify_locked(dentry);
old_bindex = bstart;
old_bstart = dbstart(dentry);
old_bend = dbend(dentry);
BUG_ON(new_bindex < 0);
BUG_ON(new_bindex >= old_bindex);
sb = dir->i_sb;
unionfs_read_lock(sb);
if ((err = is_robranch_super(sb, new_bindex))) {
dput(old_hidden_dentry);
goto out;
}
/* Create the directory structure above this dentry. */
new_hidden_dentry = create_parents_named(dir, dentry, name, new_bindex);
if (IS_ERR(new_hidden_dentry)) {
dput(old_hidden_dentry);
err = PTR_ERR(new_hidden_dentry);
goto out;
}
old_hidden_dentry = unionfs_lower_dentry_idx(dentry, old_bindex);
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)) {
symbuf = kmalloc(PATH_MAX, GFP_KERNEL);
if (!symbuf) {
__clear(dentry, old_hidden_dentry,
old_bstart, old_bend,
new_hidden_dentry, new_bindex);
err = -ENOMEM;
goto out_free;
}
oldfs = get_fs();
set_fs(KERNEL_DS);
err = old_hidden_dentry->d_inode->i_op->readlink(
old_hidden_dentry,
(char __user *)symbuf,
PATH_MAX);
set_fs(oldfs);
if (err) {
__clear(dentry, old_hidden_dentry,
old_bstart, old_bend,
new_hidden_dentry, new_bindex);
goto out_free;
}
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);
/* create the new inode */
err = __copyup_ndentry(old_hidden_dentry, new_hidden_dentry,
new_hidden_parent_dentry, symbuf);
if (err) {
__clear(dentry, old_hidden_dentry,
old_bstart, old_bend,
new_hidden_dentry, new_bindex);
goto out_unlock;
}
/* We actually copyup the file here. */
if (S_ISREG(old_hidden_dentry->d_inode->i_mode))
err = __copyup_reg_data(dentry, new_hidden_dentry, new_bindex,
old_hidden_dentry, old_bindex, copyup_file, len);
if (err)
goto out_unlink;
/* Set permissions. */
if ((err = copyup_permissions(sb, old_hidden_dentry, new_hidden_dentry)))
goto out_unlink;
#ifdef CONFIG_UNION_FS_XATTR
/* Selinux uses extended attributes for permissions. */
if ((err = copyup_xattrs(old_hidden_dentry, new_hidden_dentry)))
goto out_unlink;
#endif
/* do not allow files getting deleted to be reinterposed */
if (!d_deleted(dentry))
unionfs_reinterpose(dentry);
goto out_unlock;
/****/
out_unlink:
/* copyup failed, because we possibly ran out of space or
* quota, or something else happened so let's unlink; we don't
* really care about the return value of vfs_unlink
*/
vfs_unlink(new_hidden_parent_dentry->d_inode, new_hidden_dentry);
if (copyup_file) {
/* need to close the file */
fput(*copyup_file);
branchput(sb, new_bindex);
}
/*
* TODO: should we reset the error to something like -EIO?
*
* If we don't reset, the user may get some non-sensical errors, but
* on the other hand, if we reset to EIO, we guarantee that the user
* will get a "confusing" error message.
*/
out_unlock:
unlock_dir(new_hidden_parent_dentry);
out_free:
kfree(symbuf);
out:
unionfs_read_unlock(sb);
return err;
}