mirror of
https://github.com/AetherDroid/android_kernel_samsung_on5xelte.git
synced 2025-09-07 16:58:04 -04:00
Fixed MTP to work with TWRP
This commit is contained in:
awab228
commit
f6dfaef42e
50820 changed files with 20846062 additions and 0 deletions
833
fs/overlayfs/super.c
Normal file
833
fs/overlayfs/super.c
Normal file
|
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@ -0,0 +1,833 @@
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/*
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*
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* Copyright (C) 2011 Novell Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include <linux/xattr.h>
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#include <linux/security.h>
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#include <linux/mount.h>
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#include <linux/slab.h>
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#include <linux/parser.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/statfs.h>
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#include <linux/seq_file.h>
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#include "overlayfs.h"
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MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
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MODULE_DESCRIPTION("Overlay filesystem");
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MODULE_LICENSE("GPL");
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#define OVERLAYFS_SUPER_MAGIC 0x794c7630
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struct ovl_config {
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char *lowerdir;
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char *upperdir;
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char *workdir;
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};
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/* private information held for overlayfs's superblock */
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struct ovl_fs {
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struct vfsmount *upper_mnt;
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struct vfsmount *lower_mnt;
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struct dentry *workdir;
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long lower_namelen;
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/* pathnames of lower and upper dirs, for show_options */
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struct ovl_config config;
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};
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|
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struct ovl_dir_cache;
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||||
|
||||
/* private information held for every overlayfs dentry */
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struct ovl_entry {
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struct dentry *__upperdentry;
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struct dentry *lowerdentry;
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struct ovl_dir_cache *cache;
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union {
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struct {
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u64 version;
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bool opaque;
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};
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struct rcu_head rcu;
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};
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};
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const char *ovl_opaque_xattr = "trusted.overlay.opaque";
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enum ovl_path_type ovl_path_type(struct dentry *dentry)
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||||
{
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struct ovl_entry *oe = dentry->d_fsdata;
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||||
|
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if (oe->__upperdentry) {
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if (oe->lowerdentry) {
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if (S_ISDIR(dentry->d_inode->i_mode))
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return OVL_PATH_MERGE;
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else
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return OVL_PATH_UPPER;
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} else {
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if (oe->opaque)
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return OVL_PATH_UPPER;
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else
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return OVL_PATH_PURE_UPPER;
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}
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} else {
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return OVL_PATH_LOWER;
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}
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}
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static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
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{
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return lockless_dereference(oe->__upperdentry);
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}
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||||
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void ovl_path_upper(struct dentry *dentry, struct path *path)
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{
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struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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struct ovl_entry *oe = dentry->d_fsdata;
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path->mnt = ofs->upper_mnt;
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path->dentry = ovl_upperdentry_dereference(oe);
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}
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|
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enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
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||||
{
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|
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enum ovl_path_type type = ovl_path_type(dentry);
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|
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if (type == OVL_PATH_LOWER)
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ovl_path_lower(dentry, path);
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else
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ovl_path_upper(dentry, path);
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return type;
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||||
}
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||||
struct dentry *ovl_dentry_upper(struct dentry *dentry)
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||||
{
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||||
struct ovl_entry *oe = dentry->d_fsdata;
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||||
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||||
return ovl_upperdentry_dereference(oe);
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||||
}
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||||
|
||||
struct dentry *ovl_dentry_lower(struct dentry *dentry)
|
||||
{
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||||
struct ovl_entry *oe = dentry->d_fsdata;
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||||
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return oe->lowerdentry;
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||||
}
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||||
|
||||
struct dentry *ovl_dentry_real(struct dentry *dentry)
|
||||
{
|
||||
struct ovl_entry *oe = dentry->d_fsdata;
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||||
struct dentry *realdentry;
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realdentry = ovl_upperdentry_dereference(oe);
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if (!realdentry)
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realdentry = oe->lowerdentry;
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||||
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return realdentry;
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||||
}
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||||
|
||||
struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper)
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||||
{
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||||
struct dentry *realdentry;
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||||
|
||||
realdentry = ovl_upperdentry_dereference(oe);
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||||
if (realdentry) {
|
||||
*is_upper = true;
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||||
} else {
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||||
realdentry = oe->lowerdentry;
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||||
*is_upper = false;
|
||||
}
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||||
return realdentry;
|
||||
}
|
||||
|
||||
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
|
||||
{
|
||||
struct ovl_entry *oe = dentry->d_fsdata;
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||||
|
||||
return oe->cache;
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||||
}
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||||
|
||||
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
|
||||
{
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||||
struct ovl_entry *oe = dentry->d_fsdata;
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||||
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oe->cache = cache;
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}
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||||
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void ovl_path_lower(struct dentry *dentry, struct path *path)
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||||
{
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||||
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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struct ovl_entry *oe = dentry->d_fsdata;
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||||
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path->mnt = ofs->lower_mnt;
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||||
path->dentry = oe->lowerdentry;
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||||
}
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||||
|
||||
int ovl_want_write(struct dentry *dentry)
|
||||
{
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||||
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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||||
return mnt_want_write(ofs->upper_mnt);
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||||
}
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||||
|
||||
void ovl_drop_write(struct dentry *dentry)
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||||
{
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||||
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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||||
mnt_drop_write(ofs->upper_mnt);
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||||
}
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||||
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||||
struct dentry *ovl_workdir(struct dentry *dentry)
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||||
{
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||||
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
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||||
return ofs->workdir;
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||||
}
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||||
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||||
bool ovl_dentry_is_opaque(struct dentry *dentry)
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||||
{
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||||
struct ovl_entry *oe = dentry->d_fsdata;
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||||
return oe->opaque;
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||||
}
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||||
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void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
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||||
{
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||||
struct ovl_entry *oe = dentry->d_fsdata;
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oe->opaque = opaque;
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||||
}
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||||
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||||
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
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||||
{
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||||
struct ovl_entry *oe = dentry->d_fsdata;
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WARN_ON(!mutex_is_locked(&upperdentry->d_parent->d_inode->i_mutex));
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WARN_ON(oe->__upperdentry);
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BUG_ON(!upperdentry->d_inode);
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/*
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||||
* Make sure upperdentry is consistent before making it visible to
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* ovl_upperdentry_dereference().
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||||
*/
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||||
smp_wmb();
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oe->__upperdentry = upperdentry;
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||||
}
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||||
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||||
void ovl_dentry_version_inc(struct dentry *dentry)
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||||
{
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||||
struct ovl_entry *oe = dentry->d_fsdata;
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||||
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WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
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oe->version++;
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}
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u64 ovl_dentry_version_get(struct dentry *dentry)
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{
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struct ovl_entry *oe = dentry->d_fsdata;
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WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
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return oe->version;
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}
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bool ovl_is_whiteout(struct dentry *dentry)
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{
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struct inode *inode = dentry->d_inode;
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return inode && IS_WHITEOUT(inode);
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}
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static bool ovl_is_opaquedir(struct dentry *dentry)
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{
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int res;
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char val;
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struct inode *inode = dentry->d_inode;
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||||
if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr)
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return false;
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res = inode->i_op->getxattr(dentry, ovl_opaque_xattr, &val, 1);
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if (res == 1 && val == 'y')
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return true;
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return false;
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}
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||||
static void ovl_dentry_release(struct dentry *dentry)
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||||
{
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struct ovl_entry *oe = dentry->d_fsdata;
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if (oe) {
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dput(oe->__upperdentry);
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dput(oe->lowerdentry);
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kfree_rcu(oe, rcu);
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}
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}
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static const struct dentry_operations ovl_dentry_operations = {
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.d_release = ovl_dentry_release,
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};
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static struct ovl_entry *ovl_alloc_entry(void)
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||||
{
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return kzalloc(sizeof(struct ovl_entry), GFP_KERNEL);
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}
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static inline struct dentry *ovl_lookup_real(struct dentry *dir,
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struct qstr *name)
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||||
{
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||||
struct dentry *dentry;
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||||
mutex_lock(&dir->d_inode->i_mutex);
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dentry = lookup_one_len(name->name, dir, name->len);
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mutex_unlock(&dir->d_inode->i_mutex);
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|
||||
if (IS_ERR(dentry)) {
|
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if (PTR_ERR(dentry) == -ENOENT)
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dentry = NULL;
|
||||
} else if (!dentry->d_inode) {
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dput(dentry);
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dentry = NULL;
|
||||
}
|
||||
return dentry;
|
||||
}
|
||||
|
||||
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
|
||||
unsigned int flags)
|
||||
{
|
||||
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;
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|
||||
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) {
|
||||
if (ovl_is_whiteout(upperdentry)) {
|
||||
dput(upperdentry);
|
||||
upperdentry = NULL;
|
||||
oe->opaque = true;
|
||||
} else if (ovl_is_opaquedir(upperdentry)) {
|
||||
oe->opaque = true;
|
||||
}
|
||||
}
|
||||
}
|
||||
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;
|
||||
ovl_copyattr(realdentry->d_inode, inode);
|
||||
}
|
||||
|
||||
oe->__upperdentry = upperdentry;
|
||||
oe->lowerdentry = lowerdentry;
|
||||
|
||||
dentry->d_fsdata = oe;
|
||||
d_add(dentry, inode);
|
||||
|
||||
return NULL;
|
||||
|
||||
out_dput:
|
||||
dput(lowerdentry);
|
||||
out_dput_upper:
|
||||
dput(upperdentry);
|
||||
out_put_dir:
|
||||
kfree(oe);
|
||||
out:
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
struct file *ovl_path_open(struct path *path, int flags)
|
||||
{
|
||||
return dentry_open(path, flags, current_cred());
|
||||
}
|
||||
|
||||
static void ovl_put_super(struct super_block *sb)
|
||||
{
|
||||
struct ovl_fs *ufs = sb->s_fs_info;
|
||||
|
||||
dput(ufs->workdir);
|
||||
mntput(ufs->upper_mnt);
|
||||
mntput(ufs->lower_mnt);
|
||||
|
||||
kfree(ufs->config.lowerdir);
|
||||
kfree(ufs->config.upperdir);
|
||||
kfree(ufs->config.workdir);
|
||||
kfree(ufs);
|
||||
}
|
||||
|
||||
/**
|
||||
* ovl_statfs
|
||||
* @sb: The overlayfs super block
|
||||
* @buf: The struct kstatfs to fill in with stats
|
||||
*
|
||||
* Get the filesystem statistics. As writes always target the upper layer
|
||||
* filesystem pass the statfs to the same filesystem.
|
||||
*/
|
||||
static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
|
||||
{
|
||||
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
||||
struct dentry *root_dentry = dentry->d_sb->s_root;
|
||||
struct path path;
|
||||
int err;
|
||||
|
||||
ovl_path_upper(root_dentry, &path);
|
||||
|
||||
err = vfs_statfs(&path, buf);
|
||||
if (!err) {
|
||||
buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen);
|
||||
buf->f_type = OVERLAYFS_SUPER_MAGIC;
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
/**
|
||||
* ovl_show_options
|
||||
*
|
||||
* Prints the mount options for a given superblock.
|
||||
* Returns zero; does not fail.
|
||||
*/
|
||||
static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
|
||||
{
|
||||
struct super_block *sb = dentry->d_sb;
|
||||
struct ovl_fs *ufs = sb->s_fs_info;
|
||||
|
||||
seq_printf(m, ",lowerdir=%s", ufs->config.lowerdir);
|
||||
seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
|
||||
seq_printf(m, ",workdir=%s", ufs->config.workdir);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct super_operations ovl_super_operations = {
|
||||
.put_super = ovl_put_super,
|
||||
.statfs = ovl_statfs,
|
||||
.show_options = ovl_show_options,
|
||||
};
|
||||
|
||||
enum {
|
||||
OPT_LOWERDIR,
|
||||
OPT_UPPERDIR,
|
||||
OPT_WORKDIR,
|
||||
OPT_ERR,
|
||||
};
|
||||
|
||||
static const match_table_t ovl_tokens = {
|
||||
{OPT_LOWERDIR, "lowerdir=%s"},
|
||||
{OPT_UPPERDIR, "upperdir=%s"},
|
||||
{OPT_WORKDIR, "workdir=%s"},
|
||||
{OPT_ERR, NULL}
|
||||
};
|
||||
|
||||
static char *ovl_next_opt(char **s)
|
||||
{
|
||||
char *sbegin = *s;
|
||||
char *p;
|
||||
|
||||
if (sbegin == NULL)
|
||||
return NULL;
|
||||
|
||||
for (p = sbegin; *p; p++) {
|
||||
if (*p == '\\') {
|
||||
p++;
|
||||
if (!*p)
|
||||
break;
|
||||
} else if (*p == ',') {
|
||||
*p = '\0';
|
||||
*s = p + 1;
|
||||
return sbegin;
|
||||
}
|
||||
}
|
||||
*s = NULL;
|
||||
return sbegin;
|
||||
}
|
||||
|
||||
static int ovl_parse_opt(char *opt, struct ovl_config *config)
|
||||
{
|
||||
char *p;
|
||||
|
||||
while ((p = ovl_next_opt(&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;
|
||||
|
||||
case OPT_WORKDIR:
|
||||
kfree(config->workdir);
|
||||
config->workdir = match_strdup(&args[0]);
|
||||
if (!config->workdir)
|
||||
return -ENOMEM;
|
||||
break;
|
||||
|
||||
default:
|
||||
return -EINVAL;
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
#define OVL_WORKDIR_NAME "work"
|
||||
|
||||
static struct dentry *ovl_workdir_create(struct vfsmount *mnt,
|
||||
struct dentry *dentry)
|
||||
{
|
||||
struct inode *dir = dentry->d_inode;
|
||||
struct dentry *work;
|
||||
int err;
|
||||
bool retried = false;
|
||||
|
||||
err = mnt_want_write(mnt);
|
||||
if (err)
|
||||
return ERR_PTR(err);
|
||||
|
||||
mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
|
||||
retry:
|
||||
work = lookup_one_len(OVL_WORKDIR_NAME, dentry,
|
||||
strlen(OVL_WORKDIR_NAME));
|
||||
|
||||
if (!IS_ERR(work)) {
|
||||
struct kstat stat = {
|
||||
.mode = S_IFDIR | 0,
|
||||
};
|
||||
|
||||
if (work->d_inode) {
|
||||
err = -EEXIST;
|
||||
if (retried)
|
||||
goto out_dput;
|
||||
|
||||
retried = true;
|
||||
ovl_cleanup(dir, work);
|
||||
dput(work);
|
||||
goto retry;
|
||||
}
|
||||
|
||||
err = ovl_create_real(dir, work, &stat, NULL, NULL, true);
|
||||
if (err)
|
||||
goto out_dput;
|
||||
}
|
||||
out_unlock:
|
||||
mutex_unlock(&dir->i_mutex);
|
||||
mnt_drop_write(mnt);
|
||||
|
||||
return work;
|
||||
|
||||
out_dput:
|
||||
dput(work);
|
||||
work = ERR_PTR(err);
|
||||
goto out_unlock;
|
||||
}
|
||||
|
||||
static void ovl_unescape(char *s)
|
||||
{
|
||||
char *d = s;
|
||||
|
||||
for (;; s++, d++) {
|
||||
if (*s == '\\')
|
||||
s++;
|
||||
*d = *s;
|
||||
if (!*s)
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
static int ovl_mount_dir(const char *name, struct path *path)
|
||||
{
|
||||
int err;
|
||||
char *tmp = kstrdup(name, GFP_KERNEL);
|
||||
|
||||
if (!tmp)
|
||||
return -ENOMEM;
|
||||
|
||||
ovl_unescape(tmp);
|
||||
err = kern_path(tmp, LOOKUP_FOLLOW, path);
|
||||
if (err) {
|
||||
pr_err("overlayfs: failed to resolve '%s': %i\n", tmp, err);
|
||||
err = -EINVAL;
|
||||
}
|
||||
kfree(tmp);
|
||||
return err;
|
||||
}
|
||||
|
||||
static bool ovl_is_allowed_fs_type(struct dentry *root)
|
||||
{
|
||||
const struct dentry_operations *dop = root->d_op;
|
||||
|
||||
/*
|
||||
* We don't support:
|
||||
* - automount filesystems
|
||||
* - filesystems with revalidate (FIXME for lower layer)
|
||||
* - filesystems with case insensitive names
|
||||
*/
|
||||
if (dop &&
|
||||
(dop->d_manage || dop->d_automount ||
|
||||
dop->d_revalidate || dop->d_weak_revalidate ||
|
||||
dop->d_compare || dop->d_hash)) {
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
/* Workdir should not be subdir of upperdir and vice versa */
|
||||
static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
|
||||
{
|
||||
bool ok = false;
|
||||
|
||||
if (workdir != upperdir) {
|
||||
ok = (lock_rename(workdir, upperdir) == NULL);
|
||||
unlock_rename(workdir, upperdir);
|
||||
}
|
||||
return ok;
|
||||
}
|
||||
|
||||
static int ovl_fill_super(struct super_block *sb, void *data, int silent)
|
||||
{
|
||||
struct path lowerpath;
|
||||
struct path upperpath;
|
||||
struct path workpath;
|
||||
struct inode *root_inode;
|
||||
struct dentry *root_dentry;
|
||||
struct ovl_entry *oe;
|
||||
struct ovl_fs *ufs;
|
||||
struct kstatfs statfs;
|
||||
int err;
|
||||
|
||||
err = -ENOMEM;
|
||||
ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL);
|
||||
if (!ufs)
|
||||
goto out;
|
||||
|
||||
err = ovl_parse_opt((char *) data, &ufs->config);
|
||||
if (err)
|
||||
goto out_free_config;
|
||||
|
||||
/* FIXME: workdir is not needed for a R/O mount */
|
||||
err = -EINVAL;
|
||||
if (!ufs->config.upperdir || !ufs->config.lowerdir ||
|
||||
!ufs->config.workdir) {
|
||||
pr_err("overlayfs: missing upperdir or lowerdir or workdir\n");
|
||||
goto out_free_config;
|
||||
}
|
||||
|
||||
err = -ENOMEM;
|
||||
oe = ovl_alloc_entry();
|
||||
if (oe == NULL)
|
||||
goto out_free_config;
|
||||
|
||||
err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
|
||||
if (err)
|
||||
goto out_free_oe;
|
||||
|
||||
err = ovl_mount_dir(ufs->config.lowerdir, &lowerpath);
|
||||
if (err)
|
||||
goto out_put_upperpath;
|
||||
|
||||
err = ovl_mount_dir(ufs->config.workdir, &workpath);
|
||||
if (err)
|
||||
goto out_put_lowerpath;
|
||||
|
||||
err = -EINVAL;
|
||||
if (!S_ISDIR(upperpath.dentry->d_inode->i_mode) ||
|
||||
!S_ISDIR(lowerpath.dentry->d_inode->i_mode) ||
|
||||
!S_ISDIR(workpath.dentry->d_inode->i_mode)) {
|
||||
pr_err("overlayfs: upperdir or lowerdir or workdir not a directory\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
|
||||
if (upperpath.mnt != workpath.mnt) {
|
||||
pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) {
|
||||
pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
|
||||
if (!ovl_is_allowed_fs_type(upperpath.dentry)) {
|
||||
pr_err("overlayfs: filesystem of upperdir is not supported\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
|
||||
if (!ovl_is_allowed_fs_type(lowerpath.dentry)) {
|
||||
pr_err("overlayfs: filesystem of lowerdir is not supported\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
|
||||
err = vfs_statfs(&lowerpath, &statfs);
|
||||
if (err) {
|
||||
pr_err("overlayfs: statfs failed on lowerpath\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
ufs->lower_namelen = statfs.f_namelen;
|
||||
|
||||
sb->s_stack_depth = max(upperpath.mnt->mnt_sb->s_stack_depth,
|
||||
lowerpath.mnt->mnt_sb->s_stack_depth) + 1;
|
||||
|
||||
err = -EINVAL;
|
||||
if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
|
||||
pr_err("overlayfs: maximum fs stacking depth exceeded\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
|
||||
ufs->upper_mnt = clone_private_mount(&upperpath);
|
||||
err = PTR_ERR(ufs->upper_mnt);
|
||||
if (IS_ERR(ufs->upper_mnt)) {
|
||||
pr_err("overlayfs: failed to clone upperpath\n");
|
||||
goto out_put_workpath;
|
||||
}
|
||||
|
||||
ufs->lower_mnt = clone_private_mount(&lowerpath);
|
||||
err = PTR_ERR(ufs->lower_mnt);
|
||||
if (IS_ERR(ufs->lower_mnt)) {
|
||||
pr_err("overlayfs: failed to clone lowerpath\n");
|
||||
goto out_put_upper_mnt;
|
||||
}
|
||||
|
||||
ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
|
||||
err = PTR_ERR(ufs->workdir);
|
||||
if (IS_ERR(ufs->workdir)) {
|
||||
pr_err("overlayfs: failed to create directory %s/%s\n",
|
||||
ufs->config.workdir, OVL_WORKDIR_NAME);
|
||||
goto out_put_lower_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;
|
||||
|
||||
sb->s_d_op = &ovl_dentry_operations;
|
||||
|
||||
err = -ENOMEM;
|
||||
root_inode = ovl_new_inode(sb, S_IFDIR, oe);
|
||||
if (!root_inode)
|
||||
goto out_put_workdir;
|
||||
|
||||
root_dentry = d_make_root(root_inode);
|
||||
if (!root_dentry)
|
||||
goto out_put_workdir;
|
||||
|
||||
mntput(upperpath.mnt);
|
||||
mntput(lowerpath.mnt);
|
||||
path_put(&workpath);
|
||||
|
||||
oe->__upperdentry = upperpath.dentry;
|
||||
oe->lowerdentry = lowerpath.dentry;
|
||||
|
||||
root_dentry->d_fsdata = oe;
|
||||
|
||||
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
|
||||
sb->s_op = &ovl_super_operations;
|
||||
sb->s_root = root_dentry;
|
||||
sb->s_fs_info = ufs;
|
||||
|
||||
return 0;
|
||||
|
||||
out_put_workdir:
|
||||
dput(ufs->workdir);
|
||||
out_put_lower_mnt:
|
||||
mntput(ufs->lower_mnt);
|
||||
out_put_upper_mnt:
|
||||
mntput(ufs->upper_mnt);
|
||||
out_put_workpath:
|
||||
path_put(&workpath);
|
||||
out_put_lowerpath:
|
||||
path_put(&lowerpath);
|
||||
out_put_upperpath:
|
||||
path_put(&upperpath);
|
||||
out_free_oe:
|
||||
kfree(oe);
|
||||
out_free_config:
|
||||
kfree(ufs->config.lowerdir);
|
||||
kfree(ufs->config.upperdir);
|
||||
kfree(ufs->config.workdir);
|
||||
kfree(ufs);
|
||||
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 = "overlay",
|
||||
.mount = ovl_mount,
|
||||
.kill_sb = kill_anon_super,
|
||||
};
|
||||
MODULE_ALIAS_FS("overlay");
|
||||
|
||||
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);
|
||||
Loading…
Add table
Add a link
Reference in a new issue