blob: 5e7ceae0f9dda88d92d3ba8971747003450c62a8 [file] [log] [blame]
/*
* fs/sdcardfs/super.c
*
* Copyright (c) 2013 Samsung Electronics Co. Ltd
* Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
* Sunghwan Yun, Sungjong Seo
*
* This program has been developed as a stackable file system based on
* the WrapFS which written by
*
* Copyright (c) 1998-2011 Erez Zadok
* Copyright (c) 2009 Shrikar Archak
* Copyright (c) 2003-2011 Stony Brook University
* Copyright (c) 2003-2011 The Research Foundation of SUNY
*
* This file is dual licensed. It may be redistributed and/or modified
* under the terms of the Apache 2.0 License OR version 2 of the GNU
* General Public License.
*/
#include "sdcardfs.h"
/*
* The inode cache is used with alloc_inode for both our inode info and the
* vfs inode.
*/
static struct kmem_cache *sdcardfs_inode_cachep;
/*
* To support the top references, we must track some data separately.
* An sdcardfs_inode_info always has a reference to its data, and once set up,
* also has a reference to its top. The top may be itself, in which case it
* holds two references to its data. When top is changed, it takes a ref to the
* new data and then drops the ref to the old data.
*/
static struct kmem_cache *sdcardfs_inode_data_cachep;
void data_release(struct kref *ref)
{
struct sdcardfs_inode_data *data =
container_of(ref, struct sdcardfs_inode_data, refcount);
kmem_cache_free(sdcardfs_inode_data_cachep, data);
}
/* final actions when unmounting a file system */
static void sdcardfs_put_super(struct super_block *sb)
{
struct sdcardfs_sb_info *spd;
struct super_block *s;
spd = SDCARDFS_SB(sb);
if (!spd)
return;
if (spd->obbpath_s) {
kfree(spd->obbpath_s);
path_put(&spd->obbpath);
}
/* decrement lower super references */
s = sdcardfs_lower_super(sb);
sdcardfs_set_lower_super(sb, NULL);
atomic_dec(&s->s_active);
kfree(spd);
sb->s_fs_info = NULL;
}
static int sdcardfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
int err;
struct path lower_path;
u32 min_blocks;
struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
sdcardfs_get_lower_path(dentry, &lower_path);
err = vfs_statfs(&lower_path, buf);
sdcardfs_put_lower_path(dentry, &lower_path);
if (sbi->options.reserved_mb) {
/* Invalid statfs informations. */
if (buf->f_bsize == 0) {
pr_err("Returned block size is zero.\n");
return -EINVAL;
}
min_blocks = ((sbi->options.reserved_mb * 1024 * 1024)/buf->f_bsize);
buf->f_blocks -= min_blocks;
if (buf->f_bavail > min_blocks)
buf->f_bavail -= min_blocks;
else
buf->f_bavail = 0;
/* Make reserved blocks invisiable to media storage */
buf->f_bfree = buf->f_bavail;
}
/* set return buf to our f/s to avoid confusing user-level utils */
buf->f_type = SDCARDFS_SUPER_MAGIC;
return err;
}
/*
* @flags: numeric mount options
* @options: mount options string
*/
static int sdcardfs_remount_fs(struct super_block *sb, int *flags, char *options)
{
int err = 0;
/*
* The VFS will take care of "ro" and "rw" flags among others. We
* can safely accept a few flags (RDONLY, MANDLOCK), and honor
* SILENT, but anything else left over is an error.
*/
if ((*flags & ~(MS_RDONLY | MS_MANDLOCK | MS_SILENT)) != 0) {
pr_err("sdcardfs: remount flags 0x%x unsupported\n", *flags);
err = -EINVAL;
}
return err;
}
/*
* @mnt: mount point we are remounting
* @sb: superblock we are remounting
* @flags: numeric mount options
* @options: mount options string
*/
static int sdcardfs_remount_fs2(struct vfsmount *mnt, struct super_block *sb,
int *flags, char *options)
{
int err = 0;
/*
* The VFS will take care of "ro" and "rw" flags among others. We
* can safely accept a few flags (RDONLY, MANDLOCK), and honor
* SILENT, but anything else left over is an error.
*/
if ((*flags & ~(MS_RDONLY | MS_MANDLOCK | MS_SILENT | MS_REMOUNT)) != 0) {
pr_err("sdcardfs: remount flags 0x%x unsupported\n", *flags);
err = -EINVAL;
}
pr_info("Remount options were %s for vfsmnt %p.\n", options, mnt);
err = parse_options_remount(sb, options, *flags & ~MS_SILENT, mnt->data);
return err;
}
static void *sdcardfs_clone_mnt_data(void *data)
{
struct sdcardfs_vfsmount_options *opt = kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL);
struct sdcardfs_vfsmount_options *old = data;
if (!opt)
return NULL;
opt->gid = old->gid;
opt->mask = old->mask;
return opt;
}
static void sdcardfs_copy_mnt_data(void *data, void *newdata)
{
struct sdcardfs_vfsmount_options *old = data;
struct sdcardfs_vfsmount_options *new = newdata;
old->gid = new->gid;
old->mask = new->mask;
}
/*
* Called by iput() when the inode reference count reached zero
* and the inode is not hashed anywhere. Used to clear anything
* that needs to be, before the inode is completely destroyed and put
* on the inode free list.
*/
static void sdcardfs_evict_inode(struct inode *inode)
{
struct inode *lower_inode;
truncate_inode_pages(&inode->i_data, 0);
set_top(SDCARDFS_I(inode), NULL);
clear_inode(inode);
/*
* Decrement a reference to a lower_inode, which was incremented
* by our read_inode when it was created initially.
*/
lower_inode = sdcardfs_lower_inode(inode);
sdcardfs_set_lower_inode(inode, NULL);
iput(lower_inode);
}
static struct inode *sdcardfs_alloc_inode(struct super_block *sb)
{
struct sdcardfs_inode_info *i;
struct sdcardfs_inode_data *d;
i = kmem_cache_alloc(sdcardfs_inode_cachep, GFP_KERNEL);
if (!i)
return NULL;
/* memset everything up to the inode to 0 */
memset(i, 0, offsetof(struct sdcardfs_inode_info, vfs_inode));
d = kmem_cache_alloc(sdcardfs_inode_data_cachep,
GFP_KERNEL | __GFP_ZERO);
if (!d) {
kmem_cache_free(sdcardfs_inode_cachep, i);
return NULL;
}
i->data = d;
kref_init(&d->refcount);
i->top_data = d;
spin_lock_init(&i->top_lock);
kref_get(&d->refcount);
i->vfs_inode.i_version = 1;
return &i->vfs_inode;
}
static void i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
release_own_data(SDCARDFS_I(inode));
kmem_cache_free(sdcardfs_inode_cachep, SDCARDFS_I(inode));
}
static void sdcardfs_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, i_callback);
}
/* sdcardfs inode cache constructor */
static void init_once(void *obj)
{
struct sdcardfs_inode_info *i = obj;
inode_init_once(&i->vfs_inode);
}
int sdcardfs_init_inode_cache(void)
{
sdcardfs_inode_cachep =
kmem_cache_create("sdcardfs_inode_cache",
sizeof(struct sdcardfs_inode_info), 0,
SLAB_RECLAIM_ACCOUNT, init_once);
if (!sdcardfs_inode_cachep)
return -ENOMEM;
sdcardfs_inode_data_cachep =
kmem_cache_create("sdcardfs_inode_data_cache",
sizeof(struct sdcardfs_inode_data), 0,
SLAB_RECLAIM_ACCOUNT, NULL);
if (!sdcardfs_inode_data_cachep) {
kmem_cache_destroy(sdcardfs_inode_cachep);
return -ENOMEM;
}
return 0;
}
/* sdcardfs inode cache destructor */
void sdcardfs_destroy_inode_cache(void)
{
kmem_cache_destroy(sdcardfs_inode_data_cachep);
kmem_cache_destroy(sdcardfs_inode_cachep);
}
/*
* Used only in nfs, to kill any pending RPC tasks, so that subsequent
* code can actually succeed and won't leave tasks that need handling.
*/
static void sdcardfs_umount_begin(struct super_block *sb)
{
struct super_block *lower_sb;
lower_sb = sdcardfs_lower_super(sb);
if (lower_sb && lower_sb->s_op && lower_sb->s_op->umount_begin)
lower_sb->s_op->umount_begin(lower_sb);
}
static int sdcardfs_show_options(struct vfsmount *mnt, struct seq_file *m,
struct dentry *root)
{
struct sdcardfs_sb_info *sbi = SDCARDFS_SB(root->d_sb);
struct sdcardfs_mount_options *opts = &sbi->options;
struct sdcardfs_vfsmount_options *vfsopts = mnt->data;
if (opts->fs_low_uid != 0)
seq_printf(m, ",fsuid=%u", opts->fs_low_uid);
if (opts->fs_low_gid != 0)
seq_printf(m, ",fsgid=%u", opts->fs_low_gid);
if (vfsopts->gid != 0)
seq_printf(m, ",gid=%u", vfsopts->gid);
if (opts->multiuser)
seq_puts(m, ",multiuser");
if (vfsopts->mask)
seq_printf(m, ",mask=%u", vfsopts->mask);
if (opts->fs_user_id)
seq_printf(m, ",userid=%u", opts->fs_user_id);
if (opts->gid_derivation)
seq_puts(m, ",derive_gid");
if (opts->default_normal)
seq_puts(m, ",default_normal");
if (opts->reserved_mb != 0)
seq_printf(m, ",reserved=%uMB", opts->reserved_mb);
if (opts->nocache)
seq_printf(m, ",nocache");
if (opts->unshared_obb)
seq_printf(m, ",unshared_obb");
return 0;
};
int sdcardfs_on_fscrypt_key_removed(struct notifier_block *nb,
unsigned long action, void *data)
{
struct sdcardfs_sb_info *sbi = container_of(nb, struct sdcardfs_sb_info,
fscrypt_nb);
/*
* Evict any unused sdcardfs dentries (and hence any unused sdcardfs
* inodes, since sdcardfs doesn't cache unpinned inodes by themselves)
* so that the lower filesystem's encrypted inodes can be evicted.
* This is needed to make the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl
* properly "lock" the files underneath the sdcardfs mount.
*/
shrink_dcache_sb(sbi->sb);
return NOTIFY_OK;
}
const struct super_operations sdcardfs_sops = {
.put_super = sdcardfs_put_super,
.statfs = sdcardfs_statfs,
.remount_fs = sdcardfs_remount_fs,
.remount_fs2 = sdcardfs_remount_fs2,
.clone_mnt_data = sdcardfs_clone_mnt_data,
.copy_mnt_data = sdcardfs_copy_mnt_data,
.evict_inode = sdcardfs_evict_inode,
.umount_begin = sdcardfs_umount_begin,
.show_options2 = sdcardfs_show_options,
.alloc_inode = sdcardfs_alloc_inode,
.destroy_inode = sdcardfs_destroy_inode,
.drop_inode = generic_delete_inode,
};