source "fs/autofs4/Kconfig"
source "fs/fuse/Kconfig"
-source "fs/overlayfs/Kconfig"
config CUSE
tristate "Character device in Userspace support"
obj-$(CONFIG_AUTOFS4_FS) += autofs4/
obj-$(CONFIG_ADFS_FS) += adfs/
obj-$(CONFIG_FUSE_FS) += fuse/
-obj-$(CONFIG_OVERLAYFS_FS) += overlayfs/
obj-$(CONFIG_UDF_FS) += udf/
obj-$(CONFIG_SUN_OPENPROMFS) += openpromfs/
obj-$(CONFIG_OMFS_FS) += omfs/
+++ /dev/null
-config OVERLAYFS_FS
- tristate "Overlay filesystem support"
- help
- Add support for overlay filesystem.
+++ /dev/null
-#
-# Makefile for the overlay filesystem.
-#
-
-obj-$(CONFIG_OVERLAYFS_FS) += overlayfs.o
-
-overlayfs-objs := super.o inode.o dir.o readdir.o copy_up.o
+++ /dev/null
-/*
- *
- * Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
-
-#include <linux/fs.h>
-#include <linux/slab.h>
-#include <linux/file.h>
-#include <linux/splice.h>
-#include <linux/xattr.h>
-#include <linux/security.h>
-#include <linux/uaccess.h>
-#include "overlayfs.h"
-
-#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
-
-static int ovl_copy_up_xattr(struct dentry *old, struct dentry *new)
-{
- ssize_t list_size, size;
- char *buf, *name, *value;
- int error;
-
- if (!old->d_inode->i_op->getxattr ||
- !new->d_inode->i_op->getxattr)
- return 0;
-
- list_size = vfs_listxattr(old, NULL, 0);
- if (list_size <= 0) {
- if (list_size == -EOPNOTSUPP)
- return 0;
- return list_size;
- }
-
- buf = kzalloc(list_size, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- error = -ENOMEM;
- value = kmalloc(XATTR_SIZE_MAX, GFP_KERNEL);
- if (!value)
- goto out;
-
- list_size = vfs_listxattr(old, buf, list_size);
- if (list_size <= 0) {
- error = list_size;
- goto out_free_value;
- }
-
- for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
- size = vfs_getxattr(old, name, value, XATTR_SIZE_MAX);
- if (size <= 0) {
- error = size;
- goto out_free_value;
- }
- error = vfs_setxattr(new, name, value, size, 0);
- if (error)
- goto out_free_value;
- }
-
-out_free_value:
- kfree(value);
-out:
- kfree(buf);
- return error;
-}
-
-static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
-{
- struct file *old_file;
- struct file *new_file;
- int error = 0;
-
- if (len == 0)
- return 0;
-
- old_file = vfs_open(old, O_RDONLY, current_cred());
- if (IS_ERR(old_file))
- return PTR_ERR(old_file);
-
- new_file = vfs_open(new, O_WRONLY, current_cred());
- if (IS_ERR(new_file)) {
- error = PTR_ERR(new_file);
- goto out_fput;
- }
-
- /* FIXME: copy up sparse files efficiently */
- while (len) {
- loff_t offset = new_file->f_pos;
- size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
- long bytes;
-
- if (len < this_len)
- this_len = len;
-
- if (signal_pending_state(TASK_KILLABLE, current)) {
- error = -EINTR;
- break;
- }
-
- bytes = do_splice_direct(old_file, &offset, new_file, this_len,
- SPLICE_F_MOVE);
- if (bytes <= 0) {
- error = bytes;
- break;
- }
-
- len -= bytes;
- }
-
- fput(new_file);
-out_fput:
- fput(old_file);
- return error;
-}
-
-static char *ovl_read_symlink(struct dentry *realdentry)
-{
- int res;
- char *buf;
- struct inode *inode = realdentry->d_inode;
- mm_segment_t old_fs;
-
- res = -EINVAL;
- if (!inode->i_op->readlink)
- goto err;
-
- res = -ENOMEM;
- buf = (char *) __get_free_page(GFP_KERNEL);
- if (!buf)
- goto err;
-
- old_fs = get_fs();
- set_fs(get_ds());
- /* The cast to a user pointer is valid due to the set_fs() */
- res = inode->i_op->readlink(realdentry,
- (char __user *)buf, PAGE_SIZE - 1);
- set_fs(old_fs);
- if (res < 0) {
- free_page((unsigned long) buf);
- goto err;
- }
- buf[res] = '\0';
-
- return buf;
-
-err:
- return ERR_PTR(res);
-}
-
-static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
-{
- struct iattr attr = {
- .ia_valid = ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
- .ia_atime = stat->atime,
- .ia_mtime = stat->mtime,
- };
-
- return notify_change(upperdentry, &attr);
-}
-
-static int ovl_set_mode(struct dentry *upperdentry, umode_t mode)
-{
- struct iattr attr = {
- .ia_valid = ATTR_MODE,
- .ia_mode = mode,
- };
-
- return notify_change(upperdentry, &attr);
-}
-
-static int ovl_copy_up_locked(struct dentry *upperdir, struct dentry *dentry,
- struct path *lowerpath, struct kstat *stat,
- const char *link)
-{
- int err;
- struct path newpath;
- umode_t mode = stat->mode;
-
- /* Can't properly set mode on creation because of the umask */
- stat->mode &= S_IFMT;
-
- ovl_path_upper(dentry, &newpath);
- WARN_ON(newpath.dentry);
- newpath.dentry = ovl_upper_create(upperdir, dentry, stat, link);
- if (IS_ERR(newpath.dentry))
- return PTR_ERR(newpath.dentry);
-
- if (S_ISREG(stat->mode)) {
- err = ovl_copy_up_data(lowerpath, &newpath, stat->size);
- if (err)
- goto err_remove;
- }
-
- err = ovl_copy_up_xattr(lowerpath->dentry, newpath.dentry);
- if (err)
- goto err_remove;
-
- mutex_lock(&newpath.dentry->d_inode->i_mutex);
- if (!S_ISLNK(stat->mode))
- err = ovl_set_mode(newpath.dentry, mode);
- if (!err)
- err = ovl_set_timestamps(newpath.dentry, stat);
- mutex_unlock(&newpath.dentry->d_inode->i_mutex);
- if (err)
- goto err_remove;
-
- ovl_dentry_update(dentry, newpath.dentry);
-
- /*
- * Easiest way to get rid of the lower dentry reference is to
- * drop this dentry. This is neither needed nor possible for
- * directories.
- */
- if (!S_ISDIR(stat->mode))
- d_drop(dentry);
-
- return 0;
-
-err_remove:
- if (S_ISDIR(stat->mode))
- vfs_rmdir(upperdir->d_inode, newpath.dentry);
- else
- vfs_unlink(upperdir->d_inode, newpath.dentry);
-
- dput(newpath.dentry);
-
- return err;
-}
-
-/*
- * Copy up a single dentry
- *
- * Directory renames only allowed on "pure upper" (already created on
- * upper filesystem, never copied up). Directories which are on lower or
- * are merged may not be renamed. For these -EXDEV is returned and
- * userspace has to deal with it. This means, when copying up a
- * directory we can rely on it and ancestors being stable.
- *
- * Non-directory renames start with copy up of source if necessary. The
- * actual rename will only proceed once the copy up was successful. Copy
- * up uses upper parent i_mutex for exclusion. Since rename can change
- * d_parent it is possible that the copy up will lock the old parent. At
- * that point the file will have already been copied up anyway.
- */
-static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
- struct path *lowerpath, struct kstat *stat)
-{
- int err;
- struct kstat pstat;
- struct path parentpath;
- struct dentry *upperdir;
- const struct cred *old_cred;
- struct cred *override_cred;
- char *link = NULL;
-
- ovl_path_upper(parent, &parentpath);
- upperdir = parentpath.dentry;
-
- err = vfs_getattr(parentpath.mnt, parentpath.dentry, &pstat);
- if (err)
- return err;
-
- if (S_ISLNK(stat->mode)) {
- link = ovl_read_symlink(lowerpath->dentry);
- if (IS_ERR(link))
- return PTR_ERR(link);
- }
-
- err = -ENOMEM;
- override_cred = prepare_creds();
- if (!override_cred)
- goto out_free_link;
-
- override_cred->fsuid = stat->uid;
- override_cred->fsgid = stat->gid;
- /*
- * CAP_SYS_ADMIN for copying up extended attributes
- * CAP_DAC_OVERRIDE for create
- * CAP_FOWNER for chmod, timestamp update
- * CAP_FSETID for chmod
- * CAP_MKNOD for mknod
- */
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
- cap_raise(override_cred->cap_effective, CAP_FOWNER);
- cap_raise(override_cred->cap_effective, CAP_FSETID);
- cap_raise(override_cred->cap_effective, CAP_MKNOD);
- old_cred = override_creds(override_cred);
-
- mutex_lock_nested(&upperdir->d_inode->i_mutex, I_MUTEX_PARENT);
- if (ovl_path_type(dentry) != OVL_PATH_LOWER) {
- err = 0;
- } else {
- err = ovl_copy_up_locked(upperdir, dentry, lowerpath,
- stat, link);
- if (!err) {
- /* Restore timestamps on parent (best effort) */
- ovl_set_timestamps(upperdir, &pstat);
- }
- }
-
- mutex_unlock(&upperdir->d_inode->i_mutex);
-
- revert_creds(old_cred);
- put_cred(override_cred);
-
-out_free_link:
- if (link)
- free_page((unsigned long) link);
-
- return err;
-}
-
-int ovl_copy_up(struct dentry *dentry)
-{
- int err;
-
- err = 0;
- while (!err) {
- struct dentry *next;
- struct dentry *parent;
- struct path lowerpath;
- struct kstat stat;
- enum ovl_path_type type = ovl_path_type(dentry);
-
- if (type != OVL_PATH_LOWER)
- break;
-
- next = dget(dentry);
- /* find the topmost dentry not yet copied up */
- for (;;) {
- parent = dget_parent(next);
-
- type = ovl_path_type(parent);
- if (type != OVL_PATH_LOWER)
- break;
-
- dput(next);
- next = parent;
- }
-
- ovl_path_lower(next, &lowerpath);
- err = vfs_getattr(lowerpath.mnt, lowerpath.dentry, &stat);
- if (!err)
- err = ovl_copy_up_one(parent, next, &lowerpath, &stat);
-
- dput(parent);
- dput(next);
- }
-
- return err;
-}
-
-/* Optimize by not copying up the file first and truncating later */
-int ovl_copy_up_truncate(struct dentry *dentry, loff_t size)
-{
- int err;
- struct kstat stat;
- struct path lowerpath;
- struct dentry *parent = dget_parent(dentry);
-
- err = ovl_copy_up(parent);
- if (err)
- goto out_dput_parent;
-
- ovl_path_lower(dentry, &lowerpath);
- err = vfs_getattr(lowerpath.mnt, lowerpath.dentry, &stat);
- if (err)
- goto out_dput_parent;
-
- if (size < stat.size)
- stat.size = size;
-
- err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
-
-out_dput_parent:
- dput(parent);
- return err;
-}
+++ /dev/null
-/*
- *
- * Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
-
-#include <linux/fs.h>
-#include <linux/namei.h>
-#include <linux/xattr.h>
-#include <linux/security.h>
-#include "overlayfs.h"
-
-static const char *ovl_whiteout_symlink = "(overlay-whiteout)";
-
-static int ovl_whiteout(struct dentry *upperdir, struct dentry *dentry)
-{
- int err;
- struct dentry *newdentry;
- const struct cred *old_cred;
- struct cred *override_cred;
-
- /* FIXME: recheck lower dentry to see if whiteout is really needed */
-
- err = -ENOMEM;
- override_cred = prepare_creds();
- if (!override_cred)
- goto out;
-
- /*
- * CAP_SYS_ADMIN for setxattr
- * CAP_DAC_OVERRIDE for symlink creation
- * CAP_FOWNER for unlink in sticky directory
- */
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
- cap_raise(override_cred->cap_effective, CAP_FOWNER);
- override_cred->fsuid = 0;
- override_cred->fsgid = 0;
- old_cred = override_creds(override_cred);
-
- newdentry = lookup_one_len(dentry->d_name.name, upperdir,
- dentry->d_name.len);
- err = PTR_ERR(newdentry);
- if (IS_ERR(newdentry))
- goto out_put_cred;
-
- /* Just been removed within the same locked region */
- WARN_ON(newdentry->d_inode);
-
- err = vfs_symlink(upperdir->d_inode, newdentry, ovl_whiteout_symlink);
- if (err)
- goto out_dput;
-
- ovl_dentry_version_inc(dentry->d_parent);
-
- err = vfs_setxattr(newdentry, ovl_whiteout_xattr, "y", 1, 0);
- if (err)
- vfs_unlink(upperdir->d_inode, newdentry);
-
-out_dput:
- dput(newdentry);
-out_put_cred:
- revert_creds(old_cred);
- put_cred(override_cred);
-out:
- if (err) {
- /*
- * There's no way to recover from failure to whiteout.
- * What should we do? Log a big fat error and... ?
- */
- printk(KERN_ERR "overlayfs: ERROR - failed to whiteout '%s'\n",
- dentry->d_name.name);
- }
-
- return err;
-}
-
-static struct dentry *ovl_lookup_create(struct dentry *upperdir,
- struct dentry *template)
-{
- int err;
- struct dentry *newdentry;
- struct qstr *name = &template->d_name;
-
- newdentry = lookup_one_len(name->name, upperdir, name->len);
- if (IS_ERR(newdentry))
- return newdentry;
-
- if (newdentry->d_inode) {
- const struct cred *old_cred;
- struct cred *override_cred;
-
- /* No need to check whiteout if lower parent is non-existent */
- err = -EEXIST;
- if (!ovl_dentry_lower(template->d_parent))
- goto out_dput;
-
- if (!S_ISLNK(newdentry->d_inode->i_mode))
- goto out_dput;
-
- err = -ENOMEM;
- override_cred = prepare_creds();
- if (!override_cred)
- goto out_dput;
-
- /*
- * CAP_SYS_ADMIN for getxattr
- * CAP_FOWNER for unlink in sticky directory
- */
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- cap_raise(override_cred->cap_effective, CAP_FOWNER);
- old_cred = override_creds(override_cred);
-
- err = -EEXIST;
- if (ovl_is_whiteout(newdentry))
- err = vfs_unlink(upperdir->d_inode, newdentry);
-
- revert_creds(old_cred);
- put_cred(override_cred);
- if (err)
- goto out_dput;
-
- dput(newdentry);
- newdentry = lookup_one_len(name->name, upperdir, name->len);
- if (IS_ERR(newdentry)) {
- ovl_whiteout(upperdir, template);
- return newdentry;
- }
-
- /*
- * Whiteout just been successfully removed, parent
- * i_mutex is still held, there's no way the lookup
- * could return positive.
- */
- WARN_ON(newdentry->d_inode);
- }
-
- return newdentry;
-
-out_dput:
- dput(newdentry);
- return ERR_PTR(err);
-}
-
-struct dentry *ovl_upper_create(struct dentry *upperdir, struct dentry *dentry,
- struct kstat *stat, const char *link)
-{
- int err;
- struct dentry *newdentry;
- struct inode *dir = upperdir->d_inode;
-
- newdentry = ovl_lookup_create(upperdir, dentry);
- if (IS_ERR(newdentry))
- goto out;
-
- switch (stat->mode & S_IFMT) {
- case S_IFREG:
- err = vfs_create(dir, newdentry, stat->mode, NULL);
- break;
-
- case S_IFDIR:
- err = vfs_mkdir(dir, newdentry, stat->mode);
- break;
-
- case S_IFCHR:
- case S_IFBLK:
- case S_IFIFO:
- case S_IFSOCK:
- err = vfs_mknod(dir, newdentry, stat->mode, stat->rdev);
- break;
-
- case S_IFLNK:
- err = vfs_symlink(dir, newdentry, link);
- break;
-
- default:
- err = -EPERM;
- }
- if (err) {
- if (ovl_dentry_is_opaque(dentry))
- ovl_whiteout(upperdir, dentry);
- dput(newdentry);
- newdentry = ERR_PTR(err);
- } else if (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.
- */
- dput(newdentry);
- newdentry = ERR_PTR(-ENOENT);
- }
-
-out:
- return newdentry;
-
-}
-
-static int ovl_set_opaque(struct dentry *upperdentry)
-{
- int err;
- const struct cred *old_cred;
- struct cred *override_cred;
-
- override_cred = prepare_creds();
- if (!override_cred)
- return -ENOMEM;
-
- /* CAP_SYS_ADMIN for setxattr of "trusted" namespace */
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- old_cred = override_creds(override_cred);
- err = vfs_setxattr(upperdentry, ovl_opaque_xattr, "y", 1, 0);
- revert_creds(old_cred);
- put_cred(override_cred);
-
- return err;
-}
-
-static int ovl_remove_opaque(struct dentry *upperdentry)
-{
- int err;
- const struct cred *old_cred;
- struct cred *override_cred;
-
- override_cred = prepare_creds();
- if (!override_cred)
- return -ENOMEM;
-
- /* CAP_SYS_ADMIN for removexattr of "trusted" namespace */
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- old_cred = override_creds(override_cred);
- err = vfs_removexattr(upperdentry, ovl_opaque_xattr);
- revert_creds(old_cred);
- put_cred(override_cred);
-
- return err;
-}
-
-static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
- struct kstat *stat)
-{
- int err;
- enum ovl_path_type type;
- struct path realpath;
-
- type = ovl_path_real(dentry, &realpath);
- err = vfs_getattr(realpath.mnt, realpath.dentry, stat);
- if (err)
- return err;
-
- stat->dev = dentry->d_sb->s_dev;
- stat->ino = dentry->d_inode->i_ino;
-
- /*
- * It's probably not worth it to count subdirs to get the
- * correct link count. nlink=1 seems to pacify 'find' and
- * other utilities.
- */
- if (type == OVL_PATH_MERGE)
- stat->nlink = 1;
-
- return 0;
-}
-
-static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
- const char *link)
-{
- int err;
- struct dentry *newdentry;
- struct dentry *upperdir;
- struct inode *inode;
- struct kstat stat = {
- .mode = mode,
- .rdev = rdev,
- };
-
- err = -ENOMEM;
- inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata);
- if (!inode)
- goto out;
-
- err = ovl_copy_up(dentry->d_parent);
- if (err)
- goto out_iput;
-
- upperdir = ovl_dentry_upper(dentry->d_parent);
- mutex_lock_nested(&upperdir->d_inode->i_mutex, I_MUTEX_PARENT);
-
- newdentry = ovl_upper_create(upperdir, dentry, &stat, link);
- err = PTR_ERR(newdentry);
- if (IS_ERR(newdentry))
- goto out_unlock;
-
- ovl_dentry_version_inc(dentry->d_parent);
- if (ovl_dentry_is_opaque(dentry) && S_ISDIR(mode)) {
- err = ovl_set_opaque(newdentry);
- if (err) {
- vfs_rmdir(upperdir->d_inode, newdentry);
- ovl_whiteout(upperdir, dentry);
- goto out_dput;
- }
- }
- ovl_dentry_update(dentry, newdentry);
- d_instantiate(dentry, inode);
- inode = NULL;
- newdentry = NULL;
- err = 0;
-
-out_dput:
- dput(newdentry);
-out_unlock:
- mutex_unlock(&upperdir->d_inode->i_mutex);
-out_iput:
- iput(inode);
-out:
- return err;
-}
-
-static int ovl_create(struct inode *dir, struct dentry *dentry, int mode,
- struct nameidata *nd)
-{
- return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
-}
-
-static int ovl_mkdir(struct inode *dir, struct dentry *dentry, int mode)
-{
- return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
-}
-
-static int ovl_mknod(struct inode *dir, struct dentry *dentry, int mode,
- dev_t rdev)
-{
- return ovl_create_object(dentry, mode, rdev, NULL);
-}
-
-static int ovl_symlink(struct inode *dir, struct dentry *dentry,
- const char *link)
-{
- return ovl_create_object(dentry, S_IFLNK, 0, link);
-}
-
-static int ovl_do_remove(struct dentry *dentry, bool is_dir)
-{
- int err;
- enum ovl_path_type type;
- struct path realpath;
- struct dentry *upperdir;
-
- err = ovl_copy_up(dentry->d_parent);
- if (err)
- return err;
-
- upperdir = ovl_dentry_upper(dentry->d_parent);
- mutex_lock_nested(&upperdir->d_inode->i_mutex, I_MUTEX_PARENT);
- type = ovl_path_real(dentry, &realpath);
- if (type != OVL_PATH_LOWER) {
- err = -ESTALE;
- if (realpath.dentry->d_parent != upperdir)
- goto out_d_drop;
-
- /* FIXME: create whiteout up front and rename to target */
-
- if (is_dir)
- err = vfs_rmdir(upperdir->d_inode, realpath.dentry);
- else
- err = vfs_unlink(upperdir->d_inode, realpath.dentry);
- if (err)
- goto out_d_drop;
-
- ovl_dentry_version_inc(dentry->d_parent);
- }
-
- if (type != OVL_PATH_UPPER || ovl_dentry_is_opaque(dentry))
- err = ovl_whiteout(upperdir, 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.
- */
-out_d_drop:
- d_drop(dentry);
- mutex_unlock(&upperdir->d_inode->i_mutex);
-
- 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)
-{
- int err;
- enum ovl_path_type type;
-
- type = ovl_path_type(dentry);
- if (type != OVL_PATH_UPPER) {
- err = ovl_check_empty_and_clear(dentry, type);
- if (err)
- return err;
- }
-
- return ovl_do_remove(dentry, true);
-}
-
-static int ovl_link(struct dentry *old, struct inode *newdir,
- struct dentry *new)
-{
- int err;
- struct dentry *olddentry;
- struct dentry *newdentry;
- struct dentry *upperdir;
-
- err = ovl_copy_up(old);
- if (err)
- goto out;
-
- err = ovl_copy_up(new->d_parent);
- if (err)
- goto out;
-
- upperdir = ovl_dentry_upper(new->d_parent);
- mutex_lock_nested(&upperdir->d_inode->i_mutex, I_MUTEX_PARENT);
- newdentry = ovl_lookup_create(upperdir, new);
- err = PTR_ERR(newdentry);
- if (IS_ERR(newdentry))
- goto out_unlock;
-
- olddentry = ovl_dentry_upper(old);
- err = vfs_link(olddentry, upperdir->d_inode, newdentry);
- if (!err) {
- if (WARN_ON(!newdentry->d_inode)) {
- dput(newdentry);
- err = -ENOENT;
- goto out_unlock;
- }
-
- ovl_dentry_version_inc(new->d_parent);
- ovl_dentry_update(new, newdentry);
-
- ihold(old->d_inode);
- d_instantiate(new, old->d_inode);
- } else {
- if (ovl_dentry_is_opaque(new))
- ovl_whiteout(upperdir, new);
- dput(newdentry);
- }
-out_unlock:
- mutex_unlock(&upperdir->d_inode->i_mutex);
-out:
- return err;
-
-}
-
-static int ovl_rename(struct inode *olddir, struct dentry *old,
- struct inode *newdir, struct dentry *new)
-{
- int err;
- enum ovl_path_type old_type;
- enum ovl_path_type new_type;
- struct dentry *old_upperdir;
- struct dentry *new_upperdir;
- struct dentry *olddentry;
- struct dentry *newdentry;
- struct dentry *trap;
- bool old_opaque;
- bool new_opaque;
- bool new_create = false;
- bool is_dir = S_ISDIR(old->d_inode->i_mode);
-
- /* Don't copy up directory trees */
- old_type = ovl_path_type(old);
- if (old_type != OVL_PATH_UPPER && is_dir)
- return -EXDEV;
-
- if (new->d_inode) {
- new_type = ovl_path_type(new);
-
- if (new_type == OVL_PATH_LOWER && old_type == OVL_PATH_LOWER) {
- if (ovl_dentry_lower(old)->d_inode ==
- ovl_dentry_lower(new)->d_inode)
- return 0;
- }
- if (new_type != OVL_PATH_LOWER && old_type != OVL_PATH_LOWER) {
- if (ovl_dentry_upper(old)->d_inode ==
- ovl_dentry_upper(new)->d_inode)
- return 0;
- }
-
- if (new_type != OVL_PATH_UPPER &&
- S_ISDIR(new->d_inode->i_mode)) {
- err = ovl_check_empty_and_clear(new, new_type);
- if (err)
- return err;
- }
- } else {
- new_type = OVL_PATH_UPPER;
- }
-
- err = ovl_copy_up(old);
- if (err)
- return err;
-
- err = ovl_copy_up(new->d_parent);
- if (err)
- return err;
-
- old_upperdir = ovl_dentry_upper(old->d_parent);
- new_upperdir = ovl_dentry_upper(new->d_parent);
-
- trap = lock_rename(new_upperdir, old_upperdir);
-
- olddentry = ovl_dentry_upper(old);
- newdentry = ovl_dentry_upper(new);
- if (newdentry) {
- dget(newdentry);
- } else {
- new_create = true;
- newdentry = ovl_lookup_create(new_upperdir, new);
- err = PTR_ERR(newdentry);
- if (IS_ERR(newdentry))
- goto out_unlock;
- }
-
- err = -ESTALE;
- if (olddentry->d_parent != old_upperdir)
- goto out_dput;
- if (newdentry->d_parent != new_upperdir)
- goto out_dput;
- if (olddentry == trap)
- goto out_dput;
- if (newdentry == trap)
- goto out_dput;
-
- old_opaque = ovl_dentry_is_opaque(old);
- new_opaque = ovl_dentry_is_opaque(new) || new_type != OVL_PATH_UPPER;
-
- if (is_dir && !old_opaque && new_opaque) {
- err = ovl_set_opaque(olddentry);
- if (err)
- goto out_dput;
- }
-
- err = vfs_rename(old_upperdir->d_inode, olddentry,
- new_upperdir->d_inode, newdentry);
-
- if (err) {
- if (new_create && ovl_dentry_is_opaque(new))
- ovl_whiteout(new_upperdir, new);
- if (is_dir && !old_opaque && new_opaque)
- ovl_remove_opaque(olddentry);
- goto out_dput;
- }
-
- if (old_type != OVL_PATH_UPPER || old_opaque)
- err = ovl_whiteout(old_upperdir, old);
- if (is_dir && old_opaque && !new_opaque)
- ovl_remove_opaque(olddentry);
-
- if (old_opaque != new_opaque)
- ovl_dentry_set_opaque(old, new_opaque);
-
- ovl_dentry_version_inc(old->d_parent);
- ovl_dentry_version_inc(new->d_parent);
-
-out_dput:
- dput(newdentry);
-out_unlock:
- unlock_rename(new_upperdir, old_upperdir);
- 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_dir_getattr,
- .setxattr = ovl_setxattr,
- .getxattr = ovl_getxattr,
- .listxattr = ovl_listxattr,
- .removexattr = ovl_removexattr,
-};
+++ /dev/null
-/*
- *
- * Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
-
-#include <linux/fs.h>
-#include <linux/slab.h>
-#include <linux/xattr.h>
-#include "overlayfs.h"
-
-int ovl_setattr(struct dentry *dentry, struct iattr *attr)
-{
- struct dentry *upperdentry;
- int err;
-
- if ((attr->ia_valid & ATTR_SIZE) && !ovl_dentry_upper(dentry))
- err = ovl_copy_up_truncate(dentry, attr->ia_size);
- else
- err = ovl_copy_up(dentry);
- if (err)
- return err;
-
- upperdentry = ovl_dentry_upper(dentry);
-
- if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID))
- attr->ia_valid &= ~ATTR_MODE;
-
- mutex_lock(&upperdentry->d_inode->i_mutex);
- err = notify_change(upperdentry, attr);
- mutex_unlock(&upperdentry->d_inode->i_mutex);
-
- return err;
-}
-
-static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
- struct kstat *stat)
-{
- struct path realpath;
-
- ovl_path_real(dentry, &realpath);
- return vfs_getattr(realpath.mnt, realpath.dentry, stat);
-}
-
-int ovl_permission(struct inode *inode, int mask)
-{
- struct ovl_entry *oe;
- struct dentry *alias = NULL;
- struct inode *realinode;
- struct dentry *realdentry;
- bool is_upper;
- int err;
-
- if (S_ISDIR(inode->i_mode)) {
- oe = inode->i_private;
- } else if (mask & MAY_NOT_BLOCK) {
- return -ECHILD;
- } else {
- /*
- * For non-directories find an alias and get the info
- * from there.
- */
- spin_lock(&inode->i_lock);
- if (WARN_ON(list_empty(&inode->i_dentry))) {
- spin_unlock(&inode->i_lock);
- return -ENOENT;
- }
- alias = list_entry(inode->i_dentry.next, struct dentry, d_alias);
- dget(alias);
- spin_unlock(&inode->i_lock);
- oe = alias->d_fsdata;
- }
-
- realdentry = ovl_entry_real(oe, &is_upper);
-
- /* Careful in RCU walk mode */
- realinode = ACCESS_ONCE(realdentry->d_inode);
- if (!realinode) {
- WARN_ON(!(mask & MAY_NOT_BLOCK));
- err = -ENOENT;
- goto out_dput;
- }
-
- if (mask & MAY_WRITE) {
- umode_t mode = realinode->i_mode;
-
- /*
- * Writes will always be redirected to upper layer, so
- * ignore lower layer being read-only.
- *
- * If the overlay itself is read-only then proceed
- * with the permission check, don't return EROFS.
- * This will only happen if this is the lower layer of
- * another overlayfs.
- *
- * If upper fs becomes read-only after the overlay was
- * constructed return EROFS to prevent modification of
- * upper layer.
- */
- err = -EROFS;
- if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) &&
- (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
- goto out_dput;
-
- /*
- * Nobody gets write access to an immutable file.
- */
- err = -EACCES;
- if (IS_IMMUTABLE(realinode))
- goto out_dput;
- }
-
- if (realinode->i_op->permission)
- err = realinode->i_op->permission(realinode, mask);
- else
- err = generic_permission(realinode, mask);
-out_dput:
- dput(alias);
- return err;
-}
-
-
-struct ovl_link_data {
- struct dentry *realdentry;
- void *cookie;
-};
-
-static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
- void *ret;
- struct dentry *realdentry;
- struct inode *realinode;
-
- realdentry = ovl_dentry_real(dentry);
- realinode = realdentry->d_inode;
-
- if (WARN_ON(!realinode->i_op->follow_link))
- return ERR_PTR(-EPERM);
-
- ret = realinode->i_op->follow_link(realdentry, nd);
- if (IS_ERR(ret))
- return ret;
-
- if (realinode->i_op->put_link) {
- struct ovl_link_data *data;
-
- data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
- if (!data) {
- realinode->i_op->put_link(realdentry, nd, ret);
- return ERR_PTR(-ENOMEM);
- }
- data->realdentry = realdentry;
- data->cookie = ret;
-
- return data;
- } else {
- return NULL;
- }
-}
-
-static void ovl_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
-{
- struct inode *realinode;
- struct ovl_link_data *data = c;
-
- if (!data)
- return;
-
- realinode = data->realdentry->d_inode;
- realinode->i_op->put_link(data->realdentry, nd, data->cookie);
- kfree(data);
-}
-
-static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
-{
- struct path realpath;
- struct inode *realinode;
-
- ovl_path_real(dentry, &realpath);
- realinode = realpath.dentry->d_inode;
-
- if (!realinode->i_op->readlink)
- return -EINVAL;
-
- touch_atime(realpath.mnt, realpath.dentry);
-
- return realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
-}
-
-
-static bool ovl_is_private_xattr(const char *name)
-{
- return strncmp(name, "trusted.overlay.", 14) == 0;
-}
-
-int ovl_setxattr(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags)
-{
- int err;
- struct dentry *upperdentry;
-
- if (ovl_is_private_xattr(name))
- return -EPERM;
-
- err = ovl_copy_up(dentry);
- if (err)
- return err;
-
- upperdentry = ovl_dentry_upper(dentry);
- return vfs_setxattr(upperdentry, name, value, size, flags);
-}
-
-ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
- void *value, size_t size)
-{
- if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
- ovl_is_private_xattr(name))
- return -ENODATA;
-
- return vfs_getxattr(ovl_dentry_real(dentry), name, value, size);
-}
-
-ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
-{
- ssize_t res;
- int off;
-
- res = vfs_listxattr(ovl_dentry_real(dentry), list, size);
- if (res <= 0 || size == 0)
- return res;
-
- if (ovl_path_type(dentry->d_parent) != OVL_PATH_MERGE)
- return res;
-
- /* filter out private xattrs */
- for (off = 0; off < res;) {
- char *s = list + off;
- size_t slen = strlen(s) + 1;
-
- BUG_ON(off + slen > res);
-
- if (ovl_is_private_xattr(s)) {
- res -= slen;
- memmove(s, s + slen, res - off);
- } else {
- off += slen;
- }
- }
-
- return res;
-}
-
-int ovl_removexattr(struct dentry *dentry, const char *name)
-{
- int err;
- struct path realpath;
- enum ovl_path_type type;
-
- if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
- ovl_is_private_xattr(name))
- return -ENODATA;
-
- type = ovl_path_real(dentry, &realpath);
- if (type == OVL_PATH_LOWER) {
- err = vfs_getxattr(realpath.dentry, name, NULL, 0);
- if (err < 0)
- return err;
-
- err = ovl_copy_up(dentry);
- if (err)
- return err;
-
- ovl_path_upper(dentry, &realpath);
- }
-
- return vfs_removexattr(realpath.dentry, name);
-}
-
-static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
- struct dentry *realdentry)
-{
- if (type != OVL_PATH_LOWER)
- return false;
-
- if (special_file(realdentry->d_inode->i_mode))
- return false;
-
- if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
- return false;
-
- return true;
-}
-
-static struct file *ovl_open(struct dentry *dentry, int flags,
- const struct cred *cred)
-{
- int err;
- struct path realpath;
- enum ovl_path_type type;
-
- type = ovl_path_real(dentry, &realpath);
- if (ovl_open_need_copy_up(flags, type, realpath.dentry)) {
- if (flags & O_TRUNC)
- err = ovl_copy_up_truncate(dentry, 0);
- else
- err = ovl_copy_up(dentry);
- if (err)
- return ERR_PTR(err);
-
- ovl_path_upper(dentry, &realpath);
- }
-
- return vfs_open(&realpath, flags, cred);
-}
-
-static const struct inode_operations ovl_file_inode_operations = {
- .setattr = ovl_setattr,
- .permission = ovl_permission,
- .getattr = ovl_getattr,
- .setxattr = ovl_setxattr,
- .getxattr = ovl_getxattr,
- .listxattr = ovl_listxattr,
- .removexattr = ovl_removexattr,
- .open = ovl_open,
-};
-
-static const struct inode_operations ovl_symlink_inode_operations = {
- .setattr = ovl_setattr,
- .follow_link = ovl_follow_link,
- .put_link = ovl_put_link,
- .readlink = ovl_readlink,
- .getattr = ovl_getattr,
- .setxattr = ovl_setxattr,
- .getxattr = ovl_getxattr,
- .listxattr = ovl_listxattr,
- .removexattr = ovl_removexattr,
-};
-
-struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
- struct ovl_entry *oe)
-{
- struct inode *inode;
-
- inode = new_inode(sb);
- if (!inode)
- return NULL;
-
- mode &= S_IFMT;
-
- inode->i_ino = get_next_ino();
- inode->i_mode = mode;
- inode->i_flags |= S_NOATIME | S_NOCMTIME;
-
- switch (mode) {
- case S_IFDIR:
- inode->i_private = oe;
- inode->i_op = &ovl_dir_inode_operations;
- inode->i_fop = &ovl_dir_operations;
- break;
-
- case S_IFLNK:
- inode->i_op = &ovl_symlink_inode_operations;
- break;
-
- case S_IFREG:
- case S_IFSOCK:
- case S_IFBLK:
- case S_IFCHR:
- case S_IFIFO:
- inode->i_op = &ovl_file_inode_operations;
- break;
-
- default:
- WARN(1, "illegal file type: %i\n", mode);
- inode = NULL;
- }
-
- return inode;
-
-}
+++ /dev/null
-/*
- *
- * Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
-
-struct ovl_entry;
-
-enum ovl_path_type {
- OVL_PATH_UPPER,
- OVL_PATH_MERGE,
- OVL_PATH_LOWER,
-};
-
-extern const char *ovl_opaque_xattr;
-extern const char *ovl_whiteout_xattr;
-extern const struct dentry_operations ovl_dentry_operations;
-
-enum ovl_path_type ovl_path_type(struct dentry *dentry);
-u64 ovl_dentry_version_get(struct dentry *dentry);
-void ovl_dentry_version_inc(struct dentry *dentry);
-void ovl_path_upper(struct dentry *dentry, struct path *path);
-void ovl_path_lower(struct dentry *dentry, struct path *path);
-enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
-struct dentry *ovl_dentry_upper(struct dentry *dentry);
-struct dentry *ovl_dentry_lower(struct dentry *dentry);
-struct dentry *ovl_dentry_real(struct dentry *dentry);
-struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper);
-bool ovl_dentry_is_opaque(struct dentry *dentry);
-void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
-bool ovl_is_whiteout(struct dentry *dentry);
-void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
-struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
- struct nameidata *nd);
-
-struct dentry *ovl_upper_create(struct dentry *upperdir, struct dentry *dentry,
- struct kstat *stat, const char *link);
-
-/* readdir.c */
-extern const struct file_operations ovl_dir_operations;
-int ovl_check_empty_and_clear(struct dentry *dentry, enum ovl_path_type type);
-
-/* inode.c */
-int ovl_setattr(struct dentry *dentry, struct iattr *attr);
-int ovl_permission(struct inode *inode, int mask);
-int ovl_setxattr(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags);
-ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
- void *value, size_t size);
-ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
-int ovl_removexattr(struct dentry *dentry, const char *name);
-
-struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
- struct ovl_entry *oe);
-/* dir.c */
-extern const struct inode_operations ovl_dir_inode_operations;
-
-/* copy_up.c */
-int ovl_copy_up(struct dentry *dentry);
-int ovl_copy_up_truncate(struct dentry *dentry, loff_t size);
+++ /dev/null
-/*
- *
- * Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
-
-#include <linux/fs.h>
-#include <linux/slab.h>
-#include <linux/namei.h>
-#include <linux/file.h>
-#include <linux/xattr.h>
-#include <linux/rbtree.h>
-#include <linux/security.h>
-#include "overlayfs.h"
-
-struct ovl_cache_entry {
- const char *name;
- unsigned int len;
- unsigned int type;
- u64 ino;
- bool is_whiteout;
- struct list_head l_node;
- struct rb_node node;
-};
-
-struct ovl_readdir_data {
- struct rb_root *root;
- struct list_head *list;
- struct list_head *middle;
- struct dentry *dir;
- int count;
- int err;
-};
-
-struct ovl_dir_file {
- bool is_real;
- bool is_cached;
- struct list_head cursor;
- u64 cache_version;
- struct list_head cache;
- struct file *realfile;
-};
-
-static struct ovl_cache_entry *ovl_cache_entry_from_node(struct rb_node *n)
-{
- return container_of(n, struct ovl_cache_entry, node);
-}
-
-static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root,
- const char *name, int len)
-{
- struct rb_node *node = root->rb_node;
- int cmp;
-
- while (node) {
- struct ovl_cache_entry *p = ovl_cache_entry_from_node(node);
-
- cmp = strncmp(name, p->name, len);
- if (cmp > 0)
- node = p->node.rb_right;
- else if (cmp < 0 || len < p->len)
- node = p->node.rb_left;
- else
- return p;
- }
-
- return NULL;
-}
-
-static struct ovl_cache_entry *ovl_cache_entry_new(const char *name, int len,
- u64 ino, unsigned int d_type)
-{
- struct ovl_cache_entry *p;
-
- p = kmalloc(sizeof(*p) + len + 1, GFP_KERNEL);
- if (p) {
- char *name_copy = (char *) (p + 1);
- memcpy(name_copy, name, len);
- name_copy[len] = '\0';
- p->name = name_copy;
- p->len = len;
- p->type = d_type;
- p->ino = ino;
- p->is_whiteout = false;
- }
-
- return p;
-}
-
-static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
- const char *name, int len, u64 ino,
- unsigned int d_type)
-{
- struct rb_node **newp = &rdd->root->rb_node;
- struct rb_node *parent = NULL;
- struct ovl_cache_entry *p;
-
- while (*newp) {
- int cmp;
- struct ovl_cache_entry *tmp;
-
- parent = *newp;
- tmp = ovl_cache_entry_from_node(*newp);
- cmp = strncmp(name, tmp->name, len);
- if (cmp > 0)
- newp = &tmp->node.rb_right;
- else if (cmp < 0 || len < tmp->len)
- newp = &tmp->node.rb_left;
- else
- return 0;
- }
-
- p = ovl_cache_entry_new(name, len, ino, d_type);
- if (p == NULL)
- return -ENOMEM;
-
- list_add_tail(&p->l_node, rdd->list);
- rb_link_node(&p->node, parent, newp);
- rb_insert_color(&p->node, rdd->root);
-
- return 0;
-}
-
-static int ovl_fill_lower(void *buf, const char *name, int namelen,
- loff_t offset, u64 ino, unsigned int d_type)
-{
- struct ovl_readdir_data *rdd = buf;
- struct ovl_cache_entry *p;
-
- rdd->count++;
- p = ovl_cache_entry_find(rdd->root, name, namelen);
- if (p) {
- list_move_tail(&p->l_node, rdd->middle);
- } else {
- p = ovl_cache_entry_new(name, namelen, ino, d_type);
- if (p == NULL)
- rdd->err = -ENOMEM;
- else
- list_add_tail(&p->l_node, rdd->middle);
- }
-
- return rdd->err;
-}
-
-static void ovl_cache_free(struct list_head *list)
-{
- struct ovl_cache_entry *p;
- struct ovl_cache_entry *n;
-
- list_for_each_entry_safe(p, n, list, l_node)
- kfree(p);
-
- INIT_LIST_HEAD(list);
-}
-
-static int ovl_fill_upper(void *buf, const char *name, int namelen,
- loff_t offset, u64 ino, unsigned int d_type)
-{
- struct ovl_readdir_data *rdd = buf;
-
- rdd->count++;
- return ovl_cache_entry_add_rb(rdd, name, namelen, ino, d_type);
-}
-
-static inline int ovl_dir_read(struct path *realpath,
- struct ovl_readdir_data *rdd, filldir_t filler)
-{
- struct file *realfile;
- int err;
-
- realfile = vfs_open(realpath, O_RDONLY | O_DIRECTORY, current_cred());
- if (IS_ERR(realfile))
- return PTR_ERR(realfile);
-
- do {
- rdd->count = 0;
- rdd->err = 0;
- err = vfs_readdir(realfile, filler, rdd);
- if (err >= 0)
- err = rdd->err;
- } while (!err && rdd->count);
- fput(realfile);
-
- return 0;
-}
-
-static void ovl_dir_reset(struct file *file)
-{
- struct ovl_dir_file *od = file->private_data;
- enum ovl_path_type type = ovl_path_type(file->f_path.dentry);
-
- if (ovl_dentry_version_get(file->f_path.dentry) != od->cache_version) {
- list_del_init(&od->cursor);
- ovl_cache_free(&od->cache);
- od->is_cached = false;
- }
- WARN_ON(!od->is_real && type != OVL_PATH_MERGE);
- if (od->is_real && type == OVL_PATH_MERGE) {
- fput(od->realfile);
- od->realfile = NULL;
- od->is_real = false;
- }
-}
-
-static int ovl_dir_mark_whiteouts(struct ovl_readdir_data *rdd)
-{
- struct ovl_cache_entry *p;
- struct dentry *dentry;
- const struct cred *old_cred;
- struct cred *override_cred;
-
- override_cred = prepare_creds();
- if (!override_cred) {
- ovl_cache_free(rdd->list);
- return -ENOMEM;
- }
-
- /*
- * CAP_SYS_ADMIN for getxattr
- * CAP_DAC_OVERRIDE for lookup
- */
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
- old_cred = override_creds(override_cred);
-
- mutex_lock(&rdd->dir->d_inode->i_mutex);
- list_for_each_entry(p, rdd->list, l_node) {
- if (p->type != DT_LNK)
- continue;
-
- dentry = lookup_one_len(p->name, rdd->dir, p->len);
- if (IS_ERR(dentry))
- continue;
-
- p->is_whiteout = ovl_is_whiteout(dentry);
- dput(dentry);
- }
- mutex_unlock(&rdd->dir->d_inode->i_mutex);
-
- revert_creds(old_cred);
- put_cred(override_cred);
-
- return 0;
-}
-
-static inline int ovl_dir_read_merged(struct path *upperpath, struct path *lowerpath,
- struct ovl_readdir_data *rdd)
-{
- int err;
- struct rb_root root = RB_ROOT;
- struct list_head middle;
-
- rdd->root = &root;
- if (upperpath->dentry) {
- rdd->dir = upperpath->dentry;
- err = ovl_dir_read(upperpath, rdd, ovl_fill_upper);
- if (err)
- goto out;
-
- err = ovl_dir_mark_whiteouts(rdd);
- if (err)
- goto out;
- }
- /*
- * Insert lowerpath entries before upperpath ones, this allows
- * offsets to be reasonably constant
- */
- list_add(&middle, rdd->list);
- rdd->middle = &middle;
- err = ovl_dir_read(lowerpath, rdd, ovl_fill_lower);
- list_del(&middle);
-out:
- rdd->root = NULL;
-
- return err;
-}
-
-static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos)
-{
- struct list_head *l;
- loff_t off;
-
- l = od->cache.next;
- for (off = 0; off < pos; off++) {
- if (l == &od->cache)
- break;
- l = l->next;
- }
- list_move_tail(&od->cursor, l);
-}
-
-static int ovl_readdir(struct file *file, void *buf, filldir_t filler)
-{
- struct ovl_dir_file *od = file->private_data;
- int res;
-
- if (!file->f_pos)
- ovl_dir_reset(file);
-
- if (od->is_real) {
- res = vfs_readdir(od->realfile, filler, buf);
- file->f_pos = od->realfile->f_pos;
-
- return res;
- }
-
- if (!od->is_cached) {
- struct path lowerpath;
- struct path upperpath;
- struct ovl_readdir_data rdd = { .list = &od->cache };
-
- ovl_path_lower(file->f_path.dentry, &lowerpath);
- ovl_path_upper(file->f_path.dentry, &upperpath);
-
- res = ovl_dir_read_merged(&upperpath, &lowerpath, &rdd);
- if (res) {
- ovl_cache_free(rdd.list);
- return res;
- }
-
- od->cache_version = ovl_dentry_version_get(file->f_path.dentry);
- od->is_cached = true;
-
- ovl_seek_cursor(od, file->f_pos);
- }
-
- while (od->cursor.next != &od->cache) {
- int over;
- loff_t off;
- struct ovl_cache_entry *p;
-
- p = list_entry(od->cursor.next, struct ovl_cache_entry, l_node);
- off = file->f_pos;
- if (!p->is_whiteout) {
- over = filler(buf, p->name, p->len, off, p->ino, p->type);
- if (over)
- break;
- }
- file->f_pos++;
- list_move(&od->cursor, &p->l_node);
- }
-
- return 0;
-}
-
-static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
-{
- loff_t res;
- struct ovl_dir_file *od = file->private_data;
-
- mutex_lock(&file->f_dentry->d_inode->i_mutex);
- if (!file->f_pos)
- ovl_dir_reset(file);
-
- if (od->is_real) {
- res = vfs_llseek(od->realfile, offset, origin);
- file->f_pos = od->realfile->f_pos;
- } else {
- res = -EINVAL;
-
- switch (origin) {
- case SEEK_CUR:
- offset += file->f_pos;
- break;
- case SEEK_SET:
- break;
- default:
- goto out_unlock;
- }
- if (offset < 0)
- goto out_unlock;
-
- if (offset != file->f_pos) {
- file->f_pos = offset;
- if (od->is_cached)
- ovl_seek_cursor(od, offset);
- }
- res = offset;
- }
-out_unlock:
- mutex_unlock(&file->f_dentry->d_inode->i_mutex);
-
- return res;
-}
-
-static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
- int datasync)
-{
- struct ovl_dir_file *od = file->private_data;
-
- /* May need to reopen directory if it got copied up */
- if (!od->realfile) {
- struct path upperpath;
-
- ovl_path_upper(file->f_path.dentry, &upperpath);
- od->realfile = vfs_open(&upperpath, O_RDONLY, current_cred());
- if (IS_ERR(od->realfile))
- return PTR_ERR(od->realfile);
- }
-
- return vfs_fsync_range(od->realfile, start, end, datasync);
-}
-
-static int ovl_dir_release(struct inode *inode, struct file *file)
-{
- struct ovl_dir_file *od = file->private_data;
-
- list_del(&od->cursor);
- ovl_cache_free(&od->cache);
- if (od->realfile)
- fput(od->realfile);
- kfree(od);
-
- return 0;
-}
-
-static int ovl_dir_open(struct inode *inode, struct file *file)
-{
- struct path realpath;
- struct file *realfile;
- struct ovl_dir_file *od;
- enum ovl_path_type type;
-
- od = kzalloc(sizeof(struct ovl_dir_file), GFP_KERNEL);
- if (!od)
- return -ENOMEM;
-
- type = ovl_path_real(file->f_path.dentry, &realpath);
- realfile = vfs_open(&realpath, file->f_flags, current_cred());
- if (IS_ERR(realfile)) {
- kfree(od);
- return PTR_ERR(realfile);
- }
- INIT_LIST_HEAD(&od->cache);
- INIT_LIST_HEAD(&od->cursor);
- od->is_cached = false;
- od->realfile = realfile;
- od->is_real = (type != OVL_PATH_MERGE);
- file->private_data = od;
-
- return 0;
-}
-
-const struct file_operations ovl_dir_operations = {
- .read = generic_read_dir,
- .open = ovl_dir_open,
- .readdir = ovl_readdir,
- .llseek = ovl_dir_llseek,
- .fsync = ovl_dir_fsync,
- .release = ovl_dir_release,
-};
-
-static int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
-{
- int err;
- struct path lowerpath;
- struct path upperpath;
- struct ovl_cache_entry *p;
- struct ovl_readdir_data rdd = { .list = list };
-
- ovl_path_upper(dentry, &upperpath);
- ovl_path_lower(dentry, &lowerpath);
-
- err = ovl_dir_read_merged(&upperpath, &lowerpath, &rdd);
- if (err)
- return err;
-
- err = 0;
-
- list_for_each_entry(p, list, l_node) {
- if (p->is_whiteout)
- continue;
-
- if (p->name[0] == '.') {
- if (p->len == 1)
- continue;
- if (p->len == 2 && p->name[1] == '.')
- continue;
- }
- err = -ENOTEMPTY;
- break;
- }
-
- return err;
-}
-
-static int ovl_remove_whiteouts(struct dentry *dir, struct list_head *list)
-{
- struct path upperpath;
- struct dentry *upperdir;
- struct ovl_cache_entry *p;
- const struct cred *old_cred;
- struct cred *override_cred;
- int err;
-
- ovl_path_upper(dir, &upperpath);
- upperdir = upperpath.dentry;
-
- override_cred = prepare_creds();
- if (!override_cred)
- return -ENOMEM;
-
- /*
- * CAP_DAC_OVERRIDE for lookup and unlink
- * CAP_SYS_ADMIN for setxattr of "trusted" namespace
- * CAP_FOWNER for unlink in sticky directory
- */
- cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- cap_raise(override_cred->cap_effective, CAP_FOWNER);
- old_cred = override_creds(override_cred);
-
- err = vfs_setxattr(upperdir, ovl_opaque_xattr, "y", 1, 0);
- if (err)
- goto out_revert_creds;
-
- mutex_lock_nested(&upperdir->d_inode->i_mutex, I_MUTEX_PARENT);
- list_for_each_entry(p, list, l_node) {
- struct dentry *dentry;
- int ret;
-
- if (!p->is_whiteout)
- continue;
-
- dentry = lookup_one_len(p->name, upperdir, p->len);
- if (IS_ERR(dentry)) {
- printk(KERN_WARNING "overlayfs: failed to lookup whiteout %.*s: %li\n", p->len, p->name, PTR_ERR(dentry));
- continue;
- }
- ret = vfs_unlink(upperdir->d_inode, dentry);
- dput(dentry);
- if (ret)
- printk(KERN_WARNING "overlayfs: failed to unlink whiteout %.*s: %i\n", p->len, p->name, ret);
- }
- mutex_unlock(&upperdir->d_inode->i_mutex);
-
-out_revert_creds:
- revert_creds(old_cred);
- put_cred(override_cred);
-
- return err;
-}
-
-int ovl_check_empty_and_clear(struct dentry *dentry, enum ovl_path_type type)
-{
- int err;
- LIST_HEAD(list);
-
- err = ovl_check_empty_dir(dentry, &list);
- if (!err && type == OVL_PATH_MERGE)
- err = ovl_remove_whiteouts(dentry, &list);
-
- ovl_cache_free(&list);
-
- return err;
-}
+++ /dev/null
-/*
- *
- * Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
-
-#include <linux/fs.h>
-#include <linux/namei.h>
-#include <linux/xattr.h>
-#include <linux/security.h>
-#include <linux/mount.h>
-#include <linux/slab.h>
-#include <linux/parser.h>
-#include <linux/module.h>
-#include "overlayfs.h"
-
-MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
-MODULE_DESCRIPTION("Overlay filesystem");
-MODULE_LICENSE("GPL");
-
-struct ovl_fs {
- struct vfsmount *upper_mnt;
- struct vfsmount *lower_mnt;
-};
-
-struct ovl_entry {
- /*
- * Keep "double reference" on upper dentries, so that
- * d_delete() doesn't think it's OK to reset d_inode to NULL.
- */
- struct dentry *__upperdentry;
- struct dentry *lowerdentry;
- union {
- struct {
- u64 version;
- bool opaque;
- };
- struct rcu_head rcu;
- };
-};
-
-const char *ovl_whiteout_xattr = "trusted.overlay.whiteout";
-const char *ovl_opaque_xattr = "trusted.overlay.opaque";
-
-
-enum ovl_path_type ovl_path_type(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- if (oe->__upperdentry) {
- if (oe->lowerdentry && S_ISDIR(dentry->d_inode->i_mode))
- return OVL_PATH_MERGE;
- else
- return OVL_PATH_UPPER;
- } else {
- return OVL_PATH_LOWER;
- }
-}
-
-static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
-{
- struct dentry *upperdentry = ACCESS_ONCE(oe->__upperdentry);
- smp_read_barrier_depends();
- return upperdentry;
-}
-
-void ovl_path_upper(struct dentry *dentry, struct path *path)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct ovl_entry *oe = dentry->d_fsdata;
-
- path->mnt = ofs->upper_mnt;
- path->dentry = ovl_upperdentry_dereference(oe);
-}
-
-void ovl_path_lower(struct dentry *dentry, struct path *path)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct ovl_entry *oe = dentry->d_fsdata;
-
- path->mnt = ofs->lower_mnt;
- path->dentry = oe->lowerdentry;
-}
-
-enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
-{
-
- enum ovl_path_type type = ovl_path_type(dentry);
-
- if (type == OVL_PATH_LOWER)
- ovl_path_lower(dentry, path);
- else
- ovl_path_upper(dentry, path);
-
- return type;
-}
-
-struct dentry *ovl_dentry_upper(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return ovl_upperdentry_dereference(oe);
-}
-
-struct dentry *ovl_dentry_lower(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return oe->lowerdentry;
-}
-
-struct dentry *ovl_dentry_real(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- struct dentry *realdentry;
-
- realdentry = ovl_upperdentry_dereference(oe);
- if (!realdentry)
- realdentry = oe->lowerdentry;
-
- return realdentry;
-}
-
-struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper)
-{
- struct dentry *realdentry;
-
- realdentry = ovl_upperdentry_dereference(oe);
- if (realdentry) {
- *is_upper = true;
- } else {
- realdentry = oe->lowerdentry;
- *is_upper = false;
- }
- return realdentry;
-}
-
-bool ovl_dentry_is_opaque(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- return oe->opaque;
-}
-
-void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- oe->opaque = opaque;
-}
-
-void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!mutex_is_locked(&upperdentry->d_parent->d_inode->i_mutex));
- WARN_ON(oe->__upperdentry);
- BUG_ON(!upperdentry->d_inode);
- smp_wmb();
- oe->__upperdentry = dget(upperdentry);
-}
-
-void ovl_dentry_version_inc(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
- oe->version++;
-}
-
-u64 ovl_dentry_version_get(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
- return oe->version;
-}
-
-bool ovl_is_whiteout(struct dentry *dentry)
-{
- int res;
- char val;
-
- if (!dentry)
- return false;
- if (!dentry->d_inode)
- return false;
- if (!S_ISLNK(dentry->d_inode->i_mode))
- return false;
-
- res = vfs_getxattr(dentry, ovl_whiteout_xattr, &val, 1);
- if (res == 1 && val == 'y')
- return true;
-
- return false;
-}
-
-static bool ovl_is_opaquedir(struct dentry *dentry)
-{
- int res;
- char val;
-
- if (!S_ISDIR(dentry->d_inode->i_mode))
- return false;
-
- res = vfs_getxattr(dentry, ovl_opaque_xattr, &val, 1);
- if (res == 1 && val == 'y')
- return true;
-
- return false;
-}
-
-static void ovl_entry_free(struct rcu_head *head)
-{
- struct ovl_entry *oe = container_of(head, struct ovl_entry, rcu);
- kfree(oe);
-}
-
-static void ovl_dentry_release(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- if (oe) {
- dput(oe->__upperdentry);
- dput(oe->__upperdentry);
- dput(oe->lowerdentry);
- call_rcu(&oe->rcu, ovl_entry_free);
- }
-}
-
-const struct dentry_operations ovl_dentry_operations = {
- .d_release = ovl_dentry_release,
-};
-
-static struct ovl_entry *ovl_alloc_entry(void)
-{
- return kzalloc(sizeof(struct ovl_entry), GFP_KERNEL);
-}
-
-static inline struct dentry *ovl_lookup_real(struct dentry *dir, struct qstr *name)
-{
- struct dentry *dentry;
-
- mutex_lock(&dir->d_inode->i_mutex);
- dentry = lookup_one_len(name->name, dir, name->len);
- mutex_unlock(&dir->d_inode->i_mutex);
-
- if (IS_ERR(dentry)) {
- if (PTR_ERR(dentry) == -ENOENT)
- dentry = NULL;
- } else if (!dentry->d_inode) {
- dput(dentry);
- dentry = NULL;
- }
- return dentry;
-}
-
-static int ovl_do_lookup(struct dentry *dentry)
-{
- struct ovl_entry *oe;
- struct dentry *upperdir;
- struct dentry *lowerdir;
- struct dentry *upperdentry = NULL;
- struct dentry *lowerdentry = NULL;
- struct inode *inode = NULL;
- int err;
-
- err = -ENOMEM;
- oe = ovl_alloc_entry();
- if (!oe)
- goto out;
-
- upperdir = ovl_dentry_upper(dentry->d_parent);
- lowerdir = ovl_dentry_lower(dentry->d_parent);
-
- if (upperdir) {
- upperdentry = ovl_lookup_real(upperdir, &dentry->d_name);
- err = PTR_ERR(upperdentry);
- if (IS_ERR(upperdentry))
- goto out_put_dir;
-
- if (lowerdir && upperdentry &&
- (S_ISLNK(upperdentry->d_inode->i_mode) ||
- S_ISDIR(upperdentry->d_inode->i_mode))) {
- const struct cred *old_cred;
- struct cred *override_cred;
-
- err = -ENOMEM;
- override_cred = prepare_creds();
- if (!override_cred)
- goto out_dput_upper;
-
- /* CAP_SYS_ADMIN needed for getxattr */
- cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
- old_cred = override_creds(override_cred);
-
- if (ovl_is_opaquedir(upperdentry)) {
- oe->opaque = true;
- } else if (ovl_is_whiteout(upperdentry)) {
- dput(upperdentry);
- upperdentry = NULL;
- oe->opaque = true;
- }
- revert_creds(old_cred);
- put_cred(override_cred);
- }
- }
- if (lowerdir && !oe->opaque) {
- lowerdentry = ovl_lookup_real(lowerdir, &dentry->d_name);
- err = PTR_ERR(lowerdentry);
- if (IS_ERR(lowerdentry))
- goto out_dput_upper;
- }
-
- if (lowerdentry && upperdentry &&
- (!S_ISDIR(upperdentry->d_inode->i_mode) ||
- !S_ISDIR(lowerdentry->d_inode->i_mode))) {
- dput(lowerdentry);
- lowerdentry = NULL;
- oe->opaque = true;
- }
-
- if (lowerdentry || upperdentry) {
- struct dentry *realdentry;
-
- realdentry = upperdentry ? upperdentry : lowerdentry;
- err = -ENOMEM;
- inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode, oe);
- if (!inode)
- goto out_dput;
- }
-
- if (upperdentry)
- oe->__upperdentry = dget(upperdentry);
-
- if (lowerdentry)
- oe->lowerdentry = lowerdentry;
-
- dentry->d_fsdata = oe;
- dentry->d_op = &ovl_dentry_operations;
- d_add(dentry, inode);
-
- return 0;
-
-out_dput:
- dput(lowerdentry);
-out_dput_upper:
- dput(upperdentry);
-out_put_dir:
- kfree(oe);
-out:
- return err;
-}
-
-struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
- struct nameidata *nd)
-{
- int err = ovl_do_lookup(dentry);
-
- if (err)
- return ERR_PTR(err);
-
- return NULL;
-}
-
-static void ovl_put_super(struct super_block *sb)
-{
- struct ovl_fs *ufs = sb->s_fs_info;
-
- if (!(sb->s_flags & MS_RDONLY))
- mnt_drop_write(ufs->upper_mnt);
-
- mntput(ufs->upper_mnt);
- mntput(ufs->lower_mnt);
-
- kfree(ufs);
-}
-
-static int ovl_remount_fs(struct super_block *sb, int *flagsp, char *data)
-{
- int flags = *flagsp;
- struct ovl_fs *ufs = sb->s_fs_info;
-
- /* When remounting rw or ro, we need to adjust the write access to the
- * upper fs.
- */
- if (((flags ^ sb->s_flags) & MS_RDONLY) == 0)
- /* No change to readonly status */
- return 0;
-
- if (flags & MS_RDONLY) {
- mnt_drop_write(ufs->upper_mnt);
- return 0;
- } else
- return mnt_want_write(ufs->upper_mnt);
-}
-
-static const struct super_operations ovl_super_operations = {
- .put_super = ovl_put_super,
- .remount_fs = ovl_remount_fs,
-};
-
-struct ovl_config {
- char *lowerdir;
- char *upperdir;
-};
-
-enum {
- Opt_lowerdir,
- Opt_upperdir,
- Opt_err,
-};
-
-static const match_table_t ovl_tokens = {
- {Opt_lowerdir, "lowerdir=%s"},
- {Opt_upperdir, "upperdir=%s"},
- {Opt_err, NULL}
-};
-
-static int ovl_parse_opt(char *opt, struct ovl_config *config)
-{
- char *p;
-
- config->upperdir = NULL;
- config->lowerdir = NULL;
-
- while ((p = strsep(&opt, ",")) != NULL) {
- int token;
- substring_t args[MAX_OPT_ARGS];
-
- if (!*p)
- continue;
-
- token = match_token(p, ovl_tokens, args);
- switch (token) {
- case Opt_upperdir:
- kfree(config->upperdir);
- config->upperdir = match_strdup(&args[0]);
- if (!config->upperdir)
- return -ENOMEM;
- break;
-
- case Opt_lowerdir:
- kfree(config->lowerdir);
- config->lowerdir = match_strdup(&args[0]);
- if (!config->lowerdir)
- return -ENOMEM;
- break;
-
- default:
- return -EINVAL;
- }
- }
- return 0;
-}
-
-static int ovl_fill_super(struct super_block *sb, void *data, int silent)
-{
- struct path lowerpath;
- struct path upperpath;
- struct inode *root_inode;
- struct dentry *root_dentry;
- struct ovl_entry *oe;
- struct ovl_fs *ufs;
- struct ovl_config config;
- int err;
-
- err = ovl_parse_opt((char *) data, &config);
- if (err)
- goto out;
-
- err = -EINVAL;
- if (!config.upperdir || !config.lowerdir) {
- printk(KERN_ERR "overlayfs: missing upperdir or lowerdir\n");
- goto out_free_config;
- }
-
- err = -ENOMEM;
- ufs = kmalloc(sizeof(struct ovl_fs), GFP_KERNEL);
- if (!ufs)
- goto out_free_config;
-
- oe = ovl_alloc_entry();
- if (oe == NULL)
- goto out_free_ufs;
-
- root_inode = ovl_new_inode(sb, S_IFDIR, oe);
- if (!root_inode)
- goto out_free_oe;
-
- err = kern_path(config.upperdir, LOOKUP_FOLLOW, &upperpath);
- if (err)
- goto out_put_root;
-
- err = kern_path(config.lowerdir, LOOKUP_FOLLOW, &lowerpath);
- if (err)
- goto out_put_upperpath;
-
- err = -ENOTDIR;
- if (!S_ISDIR(upperpath.dentry->d_inode->i_mode) ||
- !S_ISDIR(lowerpath.dentry->d_inode->i_mode))
- goto out_put_lowerpath;
-
- ufs->upper_mnt = clone_private_mount(&upperpath);
- err = PTR_ERR(ufs->upper_mnt);
- if (IS_ERR(ufs->upper_mnt)) {
- printk(KERN_ERR "overlayfs: failed to clone upperpath\n");
- goto out_put_lowerpath;
- }
-
- ufs->lower_mnt = clone_private_mount(&lowerpath);
- err = PTR_ERR(ufs->lower_mnt);
- if (IS_ERR(ufs->lower_mnt)) {
- printk(KERN_ERR "overlayfs: failed to clone lowerpath\n");
- goto out_put_upper_mnt;
- }
-
- /*
- * Make lower_mnt R/O. That way fchmod/fchown on lower file
- * will fail instead of modifying lower fs.
- */
- ufs->lower_mnt->mnt_flags |= MNT_READONLY;
-
- /* If the upper fs is r/o, we mark overlayfs r/o too */
- if (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY)
- sb->s_flags |= MS_RDONLY;
-
- if (!(sb->s_flags & MS_RDONLY)) {
- err = mnt_want_write(ufs->upper_mnt);
- if (err)
- goto out_put_lower_mnt;
- }
-
- err = -ENOMEM;
- root_dentry = d_alloc_root(root_inode);
- if (!root_dentry)
- goto out_drop_write;
-
- mntput(upperpath.mnt);
- mntput(lowerpath.mnt);
-
- oe->__upperdentry = dget(upperpath.dentry);
- oe->lowerdentry = lowerpath.dentry;
-
- root_dentry->d_fsdata = oe;
- root_dentry->d_op = &ovl_dentry_operations;
-
- sb->s_op = &ovl_super_operations;
- sb->s_root = root_dentry;
- sb->s_fs_info = ufs;
-
- return 0;
-
-out_drop_write:
- if (!(sb->s_flags & MS_RDONLY))
- mnt_drop_write(ufs->upper_mnt);
-out_put_lower_mnt:
- mntput(ufs->lower_mnt);
-out_put_upper_mnt:
- mntput(ufs->upper_mnt);
-out_put_lowerpath:
- path_put(&lowerpath);
-out_put_upperpath:
- path_put(&upperpath);
-out_put_root:
- iput(root_inode);
-out_free_oe:
- kfree(oe);
-out_free_ufs:
- kfree(ufs);
-out_free_config:
- kfree(config.lowerdir);
- kfree(config.upperdir);
-out:
- return err;
-}
-
-static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
- const char *dev_name, void *raw_data)
-{
- return mount_nodev(fs_type, flags, raw_data, ovl_fill_super);
-}
-
-static struct file_system_type ovl_fs_type = {
- .owner = THIS_MODULE,
- .name = "overlayfs",
- .mount = ovl_mount,
- .kill_sb = kill_anon_super,
-};
-
-static int __init ovl_init(void)
-{
- return register_filesystem(&ovl_fs_type);
-}
-
-static void __exit ovl_exit(void)
-{
- unregister_filesystem(&ovl_fs_type);
-}
-
-module_init(ovl_init);
-module_exit(ovl_exit);
projects / linux-flexiantxendom0.git / commitdiff