mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
1318 lines
30 KiB
1318 lines
30 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* |
|
* Copyright (C) 2011 Novell Inc. |
|
*/ |
|
|
|
#include <linux/fs.h> |
|
#include <linux/namei.h> |
|
#include <linux/xattr.h> |
|
#include <linux/security.h> |
|
#include <linux/cred.h> |
|
#include <linux/module.h> |
|
#include <linux/posix_acl.h> |
|
#include <linux/posix_acl_xattr.h> |
|
#include <linux/atomic.h> |
|
#include <linux/ratelimit.h> |
|
#include "overlayfs.h" |
|
|
|
static unsigned short ovl_redirect_max = 256; |
|
module_param_named(redirect_max, ovl_redirect_max, ushort, 0644); |
|
MODULE_PARM_DESC(redirect_max, |
|
"Maximum length of absolute redirect xattr value"); |
|
|
|
static int ovl_set_redirect(struct dentry *dentry, bool samedir); |
|
|
|
int ovl_cleanup(struct ovl_fs *ofs, struct inode *wdir, struct dentry *wdentry) |
|
{ |
|
int err; |
|
|
|
dget(wdentry); |
|
if (d_is_dir(wdentry)) |
|
err = ovl_do_rmdir(ofs, wdir, wdentry); |
|
else |
|
err = ovl_do_unlink(ofs, wdir, wdentry); |
|
dput(wdentry); |
|
|
|
if (err) { |
|
pr_err("cleanup of '%pd2' failed (%i)\n", |
|
wdentry, err); |
|
} |
|
|
|
return err; |
|
} |
|
|
|
struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir) |
|
{ |
|
struct dentry *temp; |
|
char name[20]; |
|
static atomic_t temp_id = ATOMIC_INIT(0); |
|
|
|
/* counter is allowed to wrap, since temp dentries are ephemeral */ |
|
snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id)); |
|
|
|
temp = ovl_lookup_upper(ofs, name, workdir, strlen(name)); |
|
if (!IS_ERR(temp) && temp->d_inode) { |
|
pr_err("workdir/%s already exists\n", name); |
|
dput(temp); |
|
temp = ERR_PTR(-EIO); |
|
} |
|
|
|
return temp; |
|
} |
|
|
|
/* caller holds i_mutex on workdir */ |
|
static struct dentry *ovl_whiteout(struct ovl_fs *ofs) |
|
{ |
|
int err; |
|
struct dentry *whiteout; |
|
struct dentry *workdir = ofs->workdir; |
|
struct inode *wdir = workdir->d_inode; |
|
|
|
if (!ofs->whiteout) { |
|
whiteout = ovl_lookup_temp(ofs, workdir); |
|
if (IS_ERR(whiteout)) |
|
goto out; |
|
|
|
err = ovl_do_whiteout(ofs, wdir, whiteout); |
|
if (err) { |
|
dput(whiteout); |
|
whiteout = ERR_PTR(err); |
|
goto out; |
|
} |
|
ofs->whiteout = whiteout; |
|
} |
|
|
|
if (ofs->share_whiteout) { |
|
whiteout = ovl_lookup_temp(ofs, workdir); |
|
if (IS_ERR(whiteout)) |
|
goto out; |
|
|
|
err = ovl_do_link(ofs, ofs->whiteout, wdir, whiteout); |
|
if (!err) |
|
goto out; |
|
|
|
if (err != -EMLINK) { |
|
pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%i)\n", |
|
ofs->whiteout->d_inode->i_nlink, err); |
|
ofs->share_whiteout = false; |
|
} |
|
dput(whiteout); |
|
} |
|
whiteout = ofs->whiteout; |
|
ofs->whiteout = NULL; |
|
out: |
|
return whiteout; |
|
} |
|
|
|
/* Caller must hold i_mutex on both workdir and dir */ |
|
int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, |
|
struct dentry *dentry) |
|
{ |
|
struct inode *wdir = ofs->workdir->d_inode; |
|
struct dentry *whiteout; |
|
int err; |
|
int flags = 0; |
|
|
|
whiteout = ovl_whiteout(ofs); |
|
err = PTR_ERR(whiteout); |
|
if (IS_ERR(whiteout)) |
|
return err; |
|
|
|
if (d_is_dir(dentry)) |
|
flags = RENAME_EXCHANGE; |
|
|
|
err = ovl_do_rename(ofs, wdir, whiteout, dir, dentry, flags); |
|
if (err) |
|
goto kill_whiteout; |
|
if (flags) |
|
ovl_cleanup(ofs, wdir, dentry); |
|
|
|
out: |
|
dput(whiteout); |
|
return err; |
|
|
|
kill_whiteout: |
|
ovl_cleanup(ofs, wdir, whiteout); |
|
goto out; |
|
} |
|
|
|
int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir, |
|
struct dentry **newdentry, umode_t mode) |
|
{ |
|
int err; |
|
struct dentry *d, *dentry = *newdentry; |
|
|
|
err = ovl_do_mkdir(ofs, dir, dentry, mode); |
|
if (err) |
|
return err; |
|
|
|
if (likely(!d_unhashed(dentry))) |
|
return 0; |
|
|
|
/* |
|
* vfs_mkdir() may succeed and leave the dentry passed |
|
* to it unhashed and negative. If that happens, try to |
|
* lookup a new hashed and positive dentry. |
|
*/ |
|
d = ovl_lookup_upper(ofs, dentry->d_name.name, dentry->d_parent, |
|
dentry->d_name.len); |
|
if (IS_ERR(d)) { |
|
pr_warn("failed lookup after mkdir (%pd2, err=%i).\n", |
|
dentry, err); |
|
return PTR_ERR(d); |
|
} |
|
dput(dentry); |
|
*newdentry = d; |
|
|
|
return 0; |
|
} |
|
|
|
struct dentry *ovl_create_real(struct ovl_fs *ofs, struct inode *dir, |
|
struct dentry *newdentry, struct ovl_cattr *attr) |
|
{ |
|
int err; |
|
|
|
if (IS_ERR(newdentry)) |
|
return newdentry; |
|
|
|
err = -ESTALE; |
|
if (newdentry->d_inode) |
|
goto out; |
|
|
|
if (attr->hardlink) { |
|
err = ovl_do_link(ofs, attr->hardlink, dir, newdentry); |
|
} else { |
|
switch (attr->mode & S_IFMT) { |
|
case S_IFREG: |
|
err = ovl_do_create(ofs, dir, newdentry, attr->mode); |
|
break; |
|
|
|
case S_IFDIR: |
|
/* mkdir is special... */ |
|
err = ovl_mkdir_real(ofs, dir, &newdentry, attr->mode); |
|
break; |
|
|
|
case S_IFCHR: |
|
case S_IFBLK: |
|
case S_IFIFO: |
|
case S_IFSOCK: |
|
err = ovl_do_mknod(ofs, dir, newdentry, attr->mode, |
|
attr->rdev); |
|
break; |
|
|
|
case S_IFLNK: |
|
err = ovl_do_symlink(ofs, dir, newdentry, attr->link); |
|
break; |
|
|
|
default: |
|
err = -EPERM; |
|
} |
|
} |
|
if (!err && WARN_ON(!newdentry->d_inode)) { |
|
/* |
|
* Not quite sure if non-instantiated dentry is legal or not. |
|
* VFS doesn't seem to care so check and warn here. |
|
*/ |
|
err = -EIO; |
|
} |
|
out: |
|
if (err) { |
|
dput(newdentry); |
|
return ERR_PTR(err); |
|
} |
|
return newdentry; |
|
} |
|
|
|
struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir, |
|
struct ovl_cattr *attr) |
|
{ |
|
return ovl_create_real(ofs, d_inode(workdir), |
|
ovl_lookup_temp(ofs, workdir), attr); |
|
} |
|
|
|
static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper, |
|
int xerr) |
|
{ |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
int err; |
|
|
|
err = ovl_check_setxattr(ofs, upper, OVL_XATTR_OPAQUE, "y", 1, xerr); |
|
if (!err) |
|
ovl_dentry_set_opaque(dentry); |
|
|
|
return err; |
|
} |
|
|
|
static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry) |
|
{ |
|
/* |
|
* Fail with -EIO when trying to create opaque dir and upper doesn't |
|
* support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to |
|
* return a specific error for noxattr case. |
|
*/ |
|
return ovl_set_opaque_xerr(dentry, upperdentry, -EIO); |
|
} |
|
|
|
/* |
|
* Common operations required to be done after creation of file on upper. |
|
* If @hardlink is false, then @inode is a pre-allocated inode, we may or |
|
* may not use to instantiate the new dentry. |
|
*/ |
|
static int ovl_instantiate(struct dentry *dentry, struct inode *inode, |
|
struct dentry *newdentry, bool hardlink) |
|
{ |
|
struct ovl_inode_params oip = { |
|
.upperdentry = newdentry, |
|
.newinode = inode, |
|
}; |
|
|
|
ovl_dir_modified(dentry->d_parent, false); |
|
ovl_dentry_set_upper_alias(dentry); |
|
ovl_dentry_update_reval(dentry, newdentry, |
|
DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); |
|
|
|
if (!hardlink) { |
|
/* |
|
* ovl_obtain_alias() can be called after ovl_create_real() |
|
* and before we get here, so we may get an inode from cache |
|
* with the same real upperdentry that is not the inode we |
|
* pre-allocated. In this case we will use the cached inode |
|
* to instantiate the new dentry. |
|
* |
|
* XXX: if we ever use ovl_obtain_alias() to decode directory |
|
* file handles, need to use ovl_get_inode_locked() and |
|
* d_instantiate_new() here to prevent from creating two |
|
* hashed directory inode aliases. |
|
*/ |
|
inode = ovl_get_inode(dentry->d_sb, &oip); |
|
if (IS_ERR(inode)) |
|
return PTR_ERR(inode); |
|
if (inode == oip.newinode) |
|
ovl_set_flag(OVL_UPPERDATA, inode); |
|
} else { |
|
WARN_ON(ovl_inode_real(inode) != d_inode(newdentry)); |
|
dput(newdentry); |
|
inc_nlink(inode); |
|
} |
|
|
|
d_instantiate(dentry, inode); |
|
if (inode != oip.newinode) { |
|
pr_warn_ratelimited("newly created inode found in cache (%pd2)\n", |
|
dentry); |
|
} |
|
|
|
/* Force lookup of new upper hardlink to find its lower */ |
|
if (hardlink) |
|
d_drop(dentry); |
|
|
|
return 0; |
|
} |
|
|
|
static bool ovl_type_merge(struct dentry *dentry) |
|
{ |
|
return OVL_TYPE_MERGE(ovl_path_type(dentry)); |
|
} |
|
|
|
static bool ovl_type_origin(struct dentry *dentry) |
|
{ |
|
return OVL_TYPE_ORIGIN(ovl_path_type(dentry)); |
|
} |
|
|
|
static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
|
struct ovl_cattr *attr) |
|
{ |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
|
struct inode *udir = upperdir->d_inode; |
|
struct dentry *newdentry; |
|
int err; |
|
|
|
if (!attr->hardlink && !IS_POSIXACL(udir)) |
|
attr->mode &= ~current_umask(); |
|
|
|
inode_lock_nested(udir, I_MUTEX_PARENT); |
|
newdentry = ovl_create_real(ofs, udir, |
|
ovl_lookup_upper(ofs, dentry->d_name.name, |
|
upperdir, dentry->d_name.len), |
|
attr); |
|
err = PTR_ERR(newdentry); |
|
if (IS_ERR(newdentry)) |
|
goto out_unlock; |
|
|
|
if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) && |
|
!ovl_allow_offline_changes(ofs)) { |
|
/* Setting opaque here is just an optimization, allow to fail */ |
|
ovl_set_opaque(dentry, newdentry); |
|
} |
|
|
|
err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink); |
|
if (err) |
|
goto out_cleanup; |
|
out_unlock: |
|
inode_unlock(udir); |
|
return err; |
|
|
|
out_cleanup: |
|
ovl_cleanup(ofs, udir, newdentry); |
|
dput(newdentry); |
|
goto out_unlock; |
|
} |
|
|
|
static struct dentry *ovl_clear_empty(struct dentry *dentry, |
|
struct list_head *list) |
|
{ |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
struct dentry *workdir = ovl_workdir(dentry); |
|
struct inode *wdir = workdir->d_inode; |
|
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
|
struct inode *udir = upperdir->d_inode; |
|
struct path upperpath; |
|
struct dentry *upper; |
|
struct dentry *opaquedir; |
|
struct kstat stat; |
|
int err; |
|
|
|
if (WARN_ON(!workdir)) |
|
return ERR_PTR(-EROFS); |
|
|
|
err = ovl_lock_rename_workdir(workdir, upperdir); |
|
if (err) |
|
goto out; |
|
|
|
ovl_path_upper(dentry, &upperpath); |
|
err = vfs_getattr(&upperpath, &stat, |
|
STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); |
|
if (err) |
|
goto out_unlock; |
|
|
|
err = -ESTALE; |
|
if (!S_ISDIR(stat.mode)) |
|
goto out_unlock; |
|
upper = upperpath.dentry; |
|
if (upper->d_parent->d_inode != udir) |
|
goto out_unlock; |
|
|
|
opaquedir = ovl_create_temp(ofs, workdir, OVL_CATTR(stat.mode)); |
|
err = PTR_ERR(opaquedir); |
|
if (IS_ERR(opaquedir)) |
|
goto out_unlock; |
|
|
|
err = ovl_copy_xattr(dentry->d_sb, &upperpath, opaquedir); |
|
if (err) |
|
goto out_cleanup; |
|
|
|
err = ovl_set_opaque(dentry, opaquedir); |
|
if (err) |
|
goto out_cleanup; |
|
|
|
inode_lock(opaquedir->d_inode); |
|
err = ovl_set_attr(ofs, opaquedir, &stat); |
|
inode_unlock(opaquedir->d_inode); |
|
if (err) |
|
goto out_cleanup; |
|
|
|
err = ovl_do_rename(ofs, wdir, opaquedir, udir, upper, RENAME_EXCHANGE); |
|
if (err) |
|
goto out_cleanup; |
|
|
|
ovl_cleanup_whiteouts(ofs, upper, list); |
|
ovl_cleanup(ofs, wdir, upper); |
|
unlock_rename(workdir, upperdir); |
|
|
|
/* dentry's upper doesn't match now, get rid of it */ |
|
d_drop(dentry); |
|
|
|
return opaquedir; |
|
|
|
out_cleanup: |
|
ovl_cleanup(ofs, wdir, opaquedir); |
|
dput(opaquedir); |
|
out_unlock: |
|
unlock_rename(workdir, upperdir); |
|
out: |
|
return ERR_PTR(err); |
|
} |
|
|
|
static int ovl_set_upper_acl(struct ovl_fs *ofs, struct dentry *upperdentry, |
|
const char *name, const struct posix_acl *acl) |
|
{ |
|
void *buffer; |
|
size_t size; |
|
int err; |
|
|
|
if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl) |
|
return 0; |
|
|
|
size = posix_acl_xattr_size(acl->a_count); |
|
buffer = kmalloc(size, GFP_KERNEL); |
|
if (!buffer) |
|
return -ENOMEM; |
|
|
|
err = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); |
|
if (err < 0) |
|
goto out_free; |
|
|
|
err = ovl_do_setxattr(ofs, upperdentry, name, buffer, size, XATTR_CREATE); |
|
out_free: |
|
kfree(buffer); |
|
return err; |
|
} |
|
|
|
static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, |
|
struct ovl_cattr *cattr) |
|
{ |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
struct dentry *workdir = ovl_workdir(dentry); |
|
struct inode *wdir = workdir->d_inode; |
|
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
|
struct inode *udir = upperdir->d_inode; |
|
struct dentry *upper; |
|
struct dentry *newdentry; |
|
int err; |
|
struct posix_acl *acl, *default_acl; |
|
bool hardlink = !!cattr->hardlink; |
|
|
|
if (WARN_ON(!workdir)) |
|
return -EROFS; |
|
|
|
if (!hardlink) { |
|
err = posix_acl_create(dentry->d_parent->d_inode, |
|
&cattr->mode, &default_acl, &acl); |
|
if (err) |
|
return err; |
|
} |
|
|
|
err = ovl_lock_rename_workdir(workdir, upperdir); |
|
if (err) |
|
goto out; |
|
|
|
upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir, |
|
dentry->d_name.len); |
|
err = PTR_ERR(upper); |
|
if (IS_ERR(upper)) |
|
goto out_unlock; |
|
|
|
err = -ESTALE; |
|
if (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper))) |
|
goto out_dput; |
|
|
|
newdentry = ovl_create_temp(ofs, workdir, cattr); |
|
err = PTR_ERR(newdentry); |
|
if (IS_ERR(newdentry)) |
|
goto out_dput; |
|
|
|
/* |
|
* mode could have been mutilated due to umask (e.g. sgid directory) |
|
*/ |
|
if (!hardlink && |
|
!S_ISLNK(cattr->mode) && |
|
newdentry->d_inode->i_mode != cattr->mode) { |
|
struct iattr attr = { |
|
.ia_valid = ATTR_MODE, |
|
.ia_mode = cattr->mode, |
|
}; |
|
inode_lock(newdentry->d_inode); |
|
err = ovl_do_notify_change(ofs, newdentry, &attr); |
|
inode_unlock(newdentry->d_inode); |
|
if (err) |
|
goto out_cleanup; |
|
} |
|
if (!hardlink) { |
|
err = ovl_set_upper_acl(ofs, newdentry, |
|
XATTR_NAME_POSIX_ACL_ACCESS, acl); |
|
if (err) |
|
goto out_cleanup; |
|
|
|
err = ovl_set_upper_acl(ofs, newdentry, |
|
XATTR_NAME_POSIX_ACL_DEFAULT, default_acl); |
|
if (err) |
|
goto out_cleanup; |
|
} |
|
|
|
if (!hardlink && S_ISDIR(cattr->mode)) { |
|
err = ovl_set_opaque(dentry, newdentry); |
|
if (err) |
|
goto out_cleanup; |
|
|
|
err = ovl_do_rename(ofs, wdir, newdentry, udir, upper, |
|
RENAME_EXCHANGE); |
|
if (err) |
|
goto out_cleanup; |
|
|
|
ovl_cleanup(ofs, wdir, upper); |
|
} else { |
|
err = ovl_do_rename(ofs, wdir, newdentry, udir, upper, 0); |
|
if (err) |
|
goto out_cleanup; |
|
} |
|
err = ovl_instantiate(dentry, inode, newdentry, hardlink); |
|
if (err) { |
|
ovl_cleanup(ofs, udir, newdentry); |
|
dput(newdentry); |
|
} |
|
out_dput: |
|
dput(upper); |
|
out_unlock: |
|
unlock_rename(workdir, upperdir); |
|
out: |
|
if (!hardlink) { |
|
posix_acl_release(acl); |
|
posix_acl_release(default_acl); |
|
} |
|
return err; |
|
|
|
out_cleanup: |
|
ovl_cleanup(ofs, wdir, newdentry); |
|
dput(newdentry); |
|
goto out_dput; |
|
} |
|
|
|
static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, |
|
struct ovl_cattr *attr, bool origin) |
|
{ |
|
int err; |
|
const struct cred *old_cred; |
|
struct cred *override_cred; |
|
struct dentry *parent = dentry->d_parent; |
|
|
|
err = ovl_copy_up(parent); |
|
if (err) |
|
return err; |
|
|
|
old_cred = ovl_override_creds(dentry->d_sb); |
|
|
|
/* |
|
* When linking a file with copy up origin into a new parent, mark the |
|
* new parent dir "impure". |
|
*/ |
|
if (origin) { |
|
err = ovl_set_impure(parent, ovl_dentry_upper(parent)); |
|
if (err) |
|
goto out_revert_creds; |
|
} |
|
|
|
err = -ENOMEM; |
|
override_cred = prepare_creds(); |
|
if (override_cred) { |
|
override_cred->fsuid = inode->i_uid; |
|
override_cred->fsgid = inode->i_gid; |
|
if (!attr->hardlink) { |
|
err = security_dentry_create_files_as(dentry, |
|
attr->mode, &dentry->d_name, old_cred, |
|
override_cred); |
|
if (err) { |
|
put_cred(override_cred); |
|
goto out_revert_creds; |
|
} |
|
} |
|
put_cred(override_creds(override_cred)); |
|
put_cred(override_cred); |
|
|
|
if (!ovl_dentry_is_whiteout(dentry)) |
|
err = ovl_create_upper(dentry, inode, attr); |
|
else |
|
err = ovl_create_over_whiteout(dentry, inode, attr); |
|
} |
|
out_revert_creds: |
|
revert_creds(old_cred); |
|
return err; |
|
} |
|
|
|
static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, |
|
const char *link) |
|
{ |
|
int err; |
|
struct inode *inode; |
|
struct ovl_cattr attr = { |
|
.rdev = rdev, |
|
.link = link, |
|
}; |
|
|
|
err = ovl_want_write(dentry); |
|
if (err) |
|
goto out; |
|
|
|
/* Preallocate inode to be used by ovl_get_inode() */ |
|
err = -ENOMEM; |
|
inode = ovl_new_inode(dentry->d_sb, mode, rdev); |
|
if (!inode) |
|
goto out_drop_write; |
|
|
|
spin_lock(&inode->i_lock); |
|
inode->i_state |= I_CREATING; |
|
spin_unlock(&inode->i_lock); |
|
|
|
inode_init_owner(&init_user_ns, inode, dentry->d_parent->d_inode, mode); |
|
attr.mode = inode->i_mode; |
|
|
|
err = ovl_create_or_link(dentry, inode, &attr, false); |
|
/* Did we end up using the preallocated inode? */ |
|
if (inode != d_inode(dentry)) |
|
iput(inode); |
|
|
|
out_drop_write: |
|
ovl_drop_write(dentry); |
|
out: |
|
return err; |
|
} |
|
|
|
static int ovl_create(struct user_namespace *mnt_userns, struct inode *dir, |
|
struct dentry *dentry, umode_t mode, bool excl) |
|
{ |
|
return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); |
|
} |
|
|
|
static int ovl_mkdir(struct user_namespace *mnt_userns, struct inode *dir, |
|
struct dentry *dentry, umode_t mode) |
|
{ |
|
return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); |
|
} |
|
|
|
static int ovl_mknod(struct user_namespace *mnt_userns, struct inode *dir, |
|
struct dentry *dentry, umode_t mode, dev_t rdev) |
|
{ |
|
/* Don't allow creation of "whiteout" on overlay */ |
|
if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) |
|
return -EPERM; |
|
|
|
return ovl_create_object(dentry, mode, rdev, NULL); |
|
} |
|
|
|
static int ovl_symlink(struct user_namespace *mnt_userns, struct inode *dir, |
|
struct dentry *dentry, const char *link) |
|
{ |
|
return ovl_create_object(dentry, S_IFLNK, 0, link); |
|
} |
|
|
|
static int ovl_set_link_redirect(struct dentry *dentry) |
|
{ |
|
const struct cred *old_cred; |
|
int err; |
|
|
|
old_cred = ovl_override_creds(dentry->d_sb); |
|
err = ovl_set_redirect(dentry, false); |
|
revert_creds(old_cred); |
|
|
|
return err; |
|
} |
|
|
|
static int ovl_link(struct dentry *old, struct inode *newdir, |
|
struct dentry *new) |
|
{ |
|
int err; |
|
struct inode *inode; |
|
|
|
err = ovl_want_write(old); |
|
if (err) |
|
goto out; |
|
|
|
err = ovl_copy_up(old); |
|
if (err) |
|
goto out_drop_write; |
|
|
|
err = ovl_copy_up(new->d_parent); |
|
if (err) |
|
goto out_drop_write; |
|
|
|
if (ovl_is_metacopy_dentry(old)) { |
|
err = ovl_set_link_redirect(old); |
|
if (err) |
|
goto out_drop_write; |
|
} |
|
|
|
err = ovl_nlink_start(old); |
|
if (err) |
|
goto out_drop_write; |
|
|
|
inode = d_inode(old); |
|
ihold(inode); |
|
|
|
err = ovl_create_or_link(new, inode, |
|
&(struct ovl_cattr) {.hardlink = ovl_dentry_upper(old)}, |
|
ovl_type_origin(old)); |
|
if (err) |
|
iput(inode); |
|
|
|
ovl_nlink_end(old); |
|
out_drop_write: |
|
ovl_drop_write(old); |
|
out: |
|
return err; |
|
} |
|
|
|
static bool ovl_matches_upper(struct dentry *dentry, struct dentry *upper) |
|
{ |
|
return d_inode(ovl_dentry_upper(dentry)) == d_inode(upper); |
|
} |
|
|
|
static int ovl_remove_and_whiteout(struct dentry *dentry, |
|
struct list_head *list) |
|
{ |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
struct dentry *workdir = ovl_workdir(dentry); |
|
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
|
struct dentry *upper; |
|
struct dentry *opaquedir = NULL; |
|
int err; |
|
|
|
if (WARN_ON(!workdir)) |
|
return -EROFS; |
|
|
|
if (!list_empty(list)) { |
|
opaquedir = ovl_clear_empty(dentry, list); |
|
err = PTR_ERR(opaquedir); |
|
if (IS_ERR(opaquedir)) |
|
goto out; |
|
} |
|
|
|
err = ovl_lock_rename_workdir(workdir, upperdir); |
|
if (err) |
|
goto out_dput; |
|
|
|
upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir, |
|
dentry->d_name.len); |
|
err = PTR_ERR(upper); |
|
if (IS_ERR(upper)) |
|
goto out_unlock; |
|
|
|
err = -ESTALE; |
|
if ((opaquedir && upper != opaquedir) || |
|
(!opaquedir && ovl_dentry_upper(dentry) && |
|
!ovl_matches_upper(dentry, upper))) { |
|
goto out_dput_upper; |
|
} |
|
|
|
err = ovl_cleanup_and_whiteout(ofs, d_inode(upperdir), upper); |
|
if (err) |
|
goto out_d_drop; |
|
|
|
ovl_dir_modified(dentry->d_parent, true); |
|
out_d_drop: |
|
d_drop(dentry); |
|
out_dput_upper: |
|
dput(upper); |
|
out_unlock: |
|
unlock_rename(workdir, upperdir); |
|
out_dput: |
|
dput(opaquedir); |
|
out: |
|
return err; |
|
} |
|
|
|
static int ovl_remove_upper(struct dentry *dentry, bool is_dir, |
|
struct list_head *list) |
|
{ |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
|
struct inode *dir = upperdir->d_inode; |
|
struct dentry *upper; |
|
struct dentry *opaquedir = NULL; |
|
int err; |
|
|
|
if (!list_empty(list)) { |
|
opaquedir = ovl_clear_empty(dentry, list); |
|
err = PTR_ERR(opaquedir); |
|
if (IS_ERR(opaquedir)) |
|
goto out; |
|
} |
|
|
|
inode_lock_nested(dir, I_MUTEX_PARENT); |
|
upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir, |
|
dentry->d_name.len); |
|
err = PTR_ERR(upper); |
|
if (IS_ERR(upper)) |
|
goto out_unlock; |
|
|
|
err = -ESTALE; |
|
if ((opaquedir && upper != opaquedir) || |
|
(!opaquedir && !ovl_matches_upper(dentry, upper))) |
|
goto out_dput_upper; |
|
|
|
if (is_dir) |
|
err = ovl_do_rmdir(ofs, dir, upper); |
|
else |
|
err = ovl_do_unlink(ofs, dir, upper); |
|
ovl_dir_modified(dentry->d_parent, ovl_type_origin(dentry)); |
|
|
|
/* |
|
* Keeping this dentry hashed would mean having to release |
|
* upperpath/lowerpath, which could only be done if we are the |
|
* sole user of this dentry. Too tricky... Just unhash for |
|
* now. |
|
*/ |
|
if (!err) |
|
d_drop(dentry); |
|
out_dput_upper: |
|
dput(upper); |
|
out_unlock: |
|
inode_unlock(dir); |
|
dput(opaquedir); |
|
out: |
|
return err; |
|
} |
|
|
|
static bool ovl_pure_upper(struct dentry *dentry) |
|
{ |
|
return !ovl_dentry_lower(dentry) && |
|
!ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry)); |
|
} |
|
|
|
static void ovl_drop_nlink(struct dentry *dentry) |
|
{ |
|
struct inode *inode = d_inode(dentry); |
|
struct dentry *alias; |
|
|
|
/* Try to find another, hashed alias */ |
|
spin_lock(&inode->i_lock); |
|
hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { |
|
if (alias != dentry && !d_unhashed(alias)) |
|
break; |
|
} |
|
spin_unlock(&inode->i_lock); |
|
|
|
/* |
|
* Changes to underlying layers may cause i_nlink to lose sync with |
|
* reality. In this case prevent the link count from going to zero |
|
* prematurely. |
|
*/ |
|
if (inode->i_nlink > !!alias) |
|
drop_nlink(inode); |
|
} |
|
|
|
static int ovl_do_remove(struct dentry *dentry, bool is_dir) |
|
{ |
|
int err; |
|
const struct cred *old_cred; |
|
bool lower_positive = ovl_lower_positive(dentry); |
|
LIST_HEAD(list); |
|
|
|
/* No need to clean pure upper removed by vfs_rmdir() */ |
|
if (is_dir && (lower_positive || !ovl_pure_upper(dentry))) { |
|
err = ovl_check_empty_dir(dentry, &list); |
|
if (err) |
|
goto out; |
|
} |
|
|
|
err = ovl_want_write(dentry); |
|
if (err) |
|
goto out; |
|
|
|
err = ovl_copy_up(dentry->d_parent); |
|
if (err) |
|
goto out_drop_write; |
|
|
|
err = ovl_nlink_start(dentry); |
|
if (err) |
|
goto out_drop_write; |
|
|
|
old_cred = ovl_override_creds(dentry->d_sb); |
|
if (!lower_positive) |
|
err = ovl_remove_upper(dentry, is_dir, &list); |
|
else |
|
err = ovl_remove_and_whiteout(dentry, &list); |
|
revert_creds(old_cred); |
|
if (!err) { |
|
if (is_dir) |
|
clear_nlink(dentry->d_inode); |
|
else |
|
ovl_drop_nlink(dentry); |
|
} |
|
ovl_nlink_end(dentry); |
|
|
|
/* |
|
* Copy ctime |
|
* |
|
* Note: we fail to update ctime if there was no copy-up, only a |
|
* whiteout |
|
*/ |
|
if (ovl_dentry_upper(dentry)) |
|
ovl_copyattr(d_inode(dentry)); |
|
|
|
out_drop_write: |
|
ovl_drop_write(dentry); |
|
out: |
|
ovl_cache_free(&list); |
|
return err; |
|
} |
|
|
|
static int ovl_unlink(struct inode *dir, struct dentry *dentry) |
|
{ |
|
return ovl_do_remove(dentry, false); |
|
} |
|
|
|
static int ovl_rmdir(struct inode *dir, struct dentry *dentry) |
|
{ |
|
return ovl_do_remove(dentry, true); |
|
} |
|
|
|
static bool ovl_type_merge_or_lower(struct dentry *dentry) |
|
{ |
|
enum ovl_path_type type = ovl_path_type(dentry); |
|
|
|
return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type); |
|
} |
|
|
|
static bool ovl_can_move(struct dentry *dentry) |
|
{ |
|
return ovl_redirect_dir(dentry->d_sb) || |
|
!d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry); |
|
} |
|
|
|
static char *ovl_get_redirect(struct dentry *dentry, bool abs_redirect) |
|
{ |
|
char *buf, *ret; |
|
struct dentry *d, *tmp; |
|
int buflen = ovl_redirect_max + 1; |
|
|
|
if (!abs_redirect) { |
|
ret = kstrndup(dentry->d_name.name, dentry->d_name.len, |
|
GFP_KERNEL); |
|
goto out; |
|
} |
|
|
|
buf = ret = kmalloc(buflen, GFP_KERNEL); |
|
if (!buf) |
|
goto out; |
|
|
|
buflen--; |
|
buf[buflen] = '\0'; |
|
for (d = dget(dentry); !IS_ROOT(d);) { |
|
const char *name; |
|
int thislen; |
|
|
|
spin_lock(&d->d_lock); |
|
name = ovl_dentry_get_redirect(d); |
|
if (name) { |
|
thislen = strlen(name); |
|
} else { |
|
name = d->d_name.name; |
|
thislen = d->d_name.len; |
|
} |
|
|
|
/* If path is too long, fall back to userspace move */ |
|
if (thislen + (name[0] != '/') > buflen) { |
|
ret = ERR_PTR(-EXDEV); |
|
spin_unlock(&d->d_lock); |
|
goto out_put; |
|
} |
|
|
|
buflen -= thislen; |
|
memcpy(&buf[buflen], name, thislen); |
|
spin_unlock(&d->d_lock); |
|
tmp = dget_parent(d); |
|
|
|
dput(d); |
|
d = tmp; |
|
|
|
/* Absolute redirect: finished */ |
|
if (buf[buflen] == '/') |
|
break; |
|
buflen--; |
|
buf[buflen] = '/'; |
|
} |
|
ret = kstrdup(&buf[buflen], GFP_KERNEL); |
|
out_put: |
|
dput(d); |
|
kfree(buf); |
|
out: |
|
return ret ? ret : ERR_PTR(-ENOMEM); |
|
} |
|
|
|
static bool ovl_need_absolute_redirect(struct dentry *dentry, bool samedir) |
|
{ |
|
struct dentry *lowerdentry; |
|
|
|
if (!samedir) |
|
return true; |
|
|
|
if (d_is_dir(dentry)) |
|
return false; |
|
|
|
/* |
|
* For non-dir hardlinked files, we need absolute redirects |
|
* in general as two upper hardlinks could be in different |
|
* dirs. We could put a relative redirect now and convert |
|
* it to absolute redirect later. But when nlink > 1 and |
|
* indexing is on, that means relative redirect needs to be |
|
* converted to absolute during copy up of another lower |
|
* hardllink as well. |
|
* |
|
* So without optimizing too much, just check if lower is |
|
* a hard link or not. If lower is hard link, put absolute |
|
* redirect. |
|
*/ |
|
lowerdentry = ovl_dentry_lower(dentry); |
|
return (d_inode(lowerdentry)->i_nlink > 1); |
|
} |
|
|
|
static int ovl_set_redirect(struct dentry *dentry, bool samedir) |
|
{ |
|
int err; |
|
struct ovl_fs *ofs = OVL_FS(dentry->d_sb); |
|
const char *redirect = ovl_dentry_get_redirect(dentry); |
|
bool absolute_redirect = ovl_need_absolute_redirect(dentry, samedir); |
|
|
|
if (redirect && (!absolute_redirect || redirect[0] == '/')) |
|
return 0; |
|
|
|
redirect = ovl_get_redirect(dentry, absolute_redirect); |
|
if (IS_ERR(redirect)) |
|
return PTR_ERR(redirect); |
|
|
|
err = ovl_check_setxattr(ofs, ovl_dentry_upper(dentry), |
|
OVL_XATTR_REDIRECT, |
|
redirect, strlen(redirect), -EXDEV); |
|
if (!err) { |
|
spin_lock(&dentry->d_lock); |
|
ovl_dentry_set_redirect(dentry, redirect); |
|
spin_unlock(&dentry->d_lock); |
|
} else { |
|
kfree(redirect); |
|
pr_warn_ratelimited("failed to set redirect (%i)\n", |
|
err); |
|
/* Fall back to userspace copy-up */ |
|
err = -EXDEV; |
|
} |
|
return err; |
|
} |
|
|
|
static int ovl_rename(struct user_namespace *mnt_userns, struct inode *olddir, |
|
struct dentry *old, struct inode *newdir, |
|
struct dentry *new, unsigned int flags) |
|
{ |
|
int err; |
|
struct dentry *old_upperdir; |
|
struct dentry *new_upperdir; |
|
struct dentry *olddentry; |
|
struct dentry *newdentry; |
|
struct dentry *trap; |
|
bool old_opaque; |
|
bool new_opaque; |
|
bool cleanup_whiteout = false; |
|
bool update_nlink = false; |
|
bool overwrite = !(flags & RENAME_EXCHANGE); |
|
bool is_dir = d_is_dir(old); |
|
bool new_is_dir = d_is_dir(new); |
|
bool samedir = olddir == newdir; |
|
struct dentry *opaquedir = NULL; |
|
const struct cred *old_cred = NULL; |
|
struct ovl_fs *ofs = OVL_FS(old->d_sb); |
|
LIST_HEAD(list); |
|
|
|
err = -EINVAL; |
|
if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) |
|
goto out; |
|
|
|
flags &= ~RENAME_NOREPLACE; |
|
|
|
/* Don't copy up directory trees */ |
|
err = -EXDEV; |
|
if (!ovl_can_move(old)) |
|
goto out; |
|
if (!overwrite && !ovl_can_move(new)) |
|
goto out; |
|
|
|
if (overwrite && new_is_dir && !ovl_pure_upper(new)) { |
|
err = ovl_check_empty_dir(new, &list); |
|
if (err) |
|
goto out; |
|
} |
|
|
|
if (overwrite) { |
|
if (ovl_lower_positive(old)) { |
|
if (!ovl_dentry_is_whiteout(new)) { |
|
/* Whiteout source */ |
|
flags |= RENAME_WHITEOUT; |
|
} else { |
|
/* Switch whiteouts */ |
|
flags |= RENAME_EXCHANGE; |
|
} |
|
} else if (is_dir && ovl_dentry_is_whiteout(new)) { |
|
flags |= RENAME_EXCHANGE; |
|
cleanup_whiteout = true; |
|
} |
|
} |
|
|
|
err = ovl_want_write(old); |
|
if (err) |
|
goto out; |
|
|
|
err = ovl_copy_up(old); |
|
if (err) |
|
goto out_drop_write; |
|
|
|
err = ovl_copy_up(new->d_parent); |
|
if (err) |
|
goto out_drop_write; |
|
if (!overwrite) { |
|
err = ovl_copy_up(new); |
|
if (err) |
|
goto out_drop_write; |
|
} else if (d_inode(new)) { |
|
err = ovl_nlink_start(new); |
|
if (err) |
|
goto out_drop_write; |
|
|
|
update_nlink = true; |
|
} |
|
|
|
old_cred = ovl_override_creds(old->d_sb); |
|
|
|
if (!list_empty(&list)) { |
|
opaquedir = ovl_clear_empty(new, &list); |
|
err = PTR_ERR(opaquedir); |
|
if (IS_ERR(opaquedir)) { |
|
opaquedir = NULL; |
|
goto out_revert_creds; |
|
} |
|
} |
|
|
|
old_upperdir = ovl_dentry_upper(old->d_parent); |
|
new_upperdir = ovl_dentry_upper(new->d_parent); |
|
|
|
if (!samedir) { |
|
/* |
|
* When moving a merge dir or non-dir with copy up origin into |
|
* a new parent, we are marking the new parent dir "impure". |
|
* When ovl_iterate() iterates an "impure" upper dir, it will |
|
* lookup the origin inodes of the entries to fill d_ino. |
|
*/ |
|
if (ovl_type_origin(old)) { |
|
err = ovl_set_impure(new->d_parent, new_upperdir); |
|
if (err) |
|
goto out_revert_creds; |
|
} |
|
if (!overwrite && ovl_type_origin(new)) { |
|
err = ovl_set_impure(old->d_parent, old_upperdir); |
|
if (err) |
|
goto out_revert_creds; |
|
} |
|
} |
|
|
|
trap = lock_rename(new_upperdir, old_upperdir); |
|
|
|
olddentry = ovl_lookup_upper(ofs, old->d_name.name, old_upperdir, |
|
old->d_name.len); |
|
err = PTR_ERR(olddentry); |
|
if (IS_ERR(olddentry)) |
|
goto out_unlock; |
|
|
|
err = -ESTALE; |
|
if (!ovl_matches_upper(old, olddentry)) |
|
goto out_dput_old; |
|
|
|
newdentry = ovl_lookup_upper(ofs, new->d_name.name, new_upperdir, |
|
new->d_name.len); |
|
err = PTR_ERR(newdentry); |
|
if (IS_ERR(newdentry)) |
|
goto out_dput_old; |
|
|
|
old_opaque = ovl_dentry_is_opaque(old); |
|
new_opaque = ovl_dentry_is_opaque(new); |
|
|
|
err = -ESTALE; |
|
if (d_inode(new) && ovl_dentry_upper(new)) { |
|
if (opaquedir) { |
|
if (newdentry != opaquedir) |
|
goto out_dput; |
|
} else { |
|
if (!ovl_matches_upper(new, newdentry)) |
|
goto out_dput; |
|
} |
|
} else { |
|
if (!d_is_negative(newdentry)) { |
|
if (!new_opaque || !ovl_is_whiteout(newdentry)) |
|
goto out_dput; |
|
} else { |
|
if (flags & RENAME_EXCHANGE) |
|
goto out_dput; |
|
} |
|
} |
|
|
|
if (olddentry == trap) |
|
goto out_dput; |
|
if (newdentry == trap) |
|
goto out_dput; |
|
|
|
if (olddentry->d_inode == newdentry->d_inode) |
|
goto out_dput; |
|
|
|
err = 0; |
|
if (ovl_type_merge_or_lower(old)) |
|
err = ovl_set_redirect(old, samedir); |
|
else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent)) |
|
err = ovl_set_opaque_xerr(old, olddentry, -EXDEV); |
|
if (err) |
|
goto out_dput; |
|
|
|
if (!overwrite && ovl_type_merge_or_lower(new)) |
|
err = ovl_set_redirect(new, samedir); |
|
else if (!overwrite && new_is_dir && !new_opaque && |
|
ovl_type_merge(old->d_parent)) |
|
err = ovl_set_opaque_xerr(new, newdentry, -EXDEV); |
|
if (err) |
|
goto out_dput; |
|
|
|
err = ovl_do_rename(ofs, old_upperdir->d_inode, olddentry, |
|
new_upperdir->d_inode, newdentry, flags); |
|
if (err) |
|
goto out_dput; |
|
|
|
if (cleanup_whiteout) |
|
ovl_cleanup(ofs, old_upperdir->d_inode, newdentry); |
|
|
|
if (overwrite && d_inode(new)) { |
|
if (new_is_dir) |
|
clear_nlink(d_inode(new)); |
|
else |
|
ovl_drop_nlink(new); |
|
} |
|
|
|
ovl_dir_modified(old->d_parent, ovl_type_origin(old) || |
|
(!overwrite && ovl_type_origin(new))); |
|
ovl_dir_modified(new->d_parent, ovl_type_origin(old) || |
|
(d_inode(new) && ovl_type_origin(new))); |
|
|
|
/* copy ctime: */ |
|
ovl_copyattr(d_inode(old)); |
|
if (d_inode(new) && ovl_dentry_upper(new)) |
|
ovl_copyattr(d_inode(new)); |
|
|
|
out_dput: |
|
dput(newdentry); |
|
out_dput_old: |
|
dput(olddentry); |
|
out_unlock: |
|
unlock_rename(new_upperdir, old_upperdir); |
|
out_revert_creds: |
|
revert_creds(old_cred); |
|
if (update_nlink) |
|
ovl_nlink_end(new); |
|
out_drop_write: |
|
ovl_drop_write(old); |
|
out: |
|
dput(opaquedir); |
|
ovl_cache_free(&list); |
|
return err; |
|
} |
|
|
|
const struct inode_operations ovl_dir_inode_operations = { |
|
.lookup = ovl_lookup, |
|
.mkdir = ovl_mkdir, |
|
.symlink = ovl_symlink, |
|
.unlink = ovl_unlink, |
|
.rmdir = ovl_rmdir, |
|
.rename = ovl_rename, |
|
.link = ovl_link, |
|
.setattr = ovl_setattr, |
|
.create = ovl_create, |
|
.mknod = ovl_mknod, |
|
.permission = ovl_permission, |
|
.getattr = ovl_getattr, |
|
.listxattr = ovl_listxattr, |
|
.get_acl = ovl_get_acl, |
|
.update_time = ovl_update_time, |
|
.fileattr_get = ovl_fileattr_get, |
|
.fileattr_set = ovl_fileattr_set, |
|
};
|
|
|