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ANDROID: sdcardfs: Add gid and mask to private mount data

Browse source 
Adds support for mount2, remount2, and the functions
to allocate/clone/copy the private data

The next patch will switch over to actually using it.

Change-Id: I8a43da26021d33401f655f0b2784ead161c575e3
Signed-off-by: Daniel Rosenberg <drosen@google.com>
This commit is contained in:
Daniel Rosenberg 2016-10-26 17:36:05 -07:00 committed by Amit Pundir
parent bcc8f0a225
commit 424d3c9024
3 changed files with 157 additions and 18 deletions
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103
fs/sdcardfs/main.c
View file

@ -49,7 +49,8 @@ static const match_table_t sdcardfs_tokens = {
};
static int parse_options(struct super_block *sb, char *options, int silent,
int *debug, struct sdcardfs_mount_options *opts)
int *debug, struct sdcardfs_vfsmount_options *vfsopts,
struct sdcardfs_mount_options *opts)
{
char *p;
substring_t args[MAX_OPT_ARGS];
@ -58,9 +59,11 @@ static int parse_options(struct super_block *sb, char *options, int silent,
/* by default, we use AID_MEDIA_RW as uid, gid */
opts->fs_low_uid = AID_MEDIA_RW;
opts->fs_low_gid = AID_MEDIA_RW;
vfsopts->mask = 0;
opts->mask = 0;
opts->multiuser = false;
opts->fs_user_id = 0;
vfsopts->gid = 0;
opts->gid = 0;
/* by default, 0MB is reserved */
opts->reserved_mb = 0;
@ -95,6 +98,7 @@ static int parse_options(struct super_block *sb, char *options, int silent,
if (match_int(&args[0], &option))
return 0;
opts->gid = option;
vfsopts->gid = option;
break;
case Opt_userid:
if (match_int(&args[0], &option))
@ -105,6 +109,7 @@ static int parse_options(struct super_block *sb, char *options, int silent,
if (match_int(&args[0], &option))
return 0;
opts->mask = option;
vfsopts->mask = option;
break;
case Opt_multiuser:
opts->multiuser = true;
@ -135,6 +140,65 @@ static int parse_options(struct super_block *sb, char *options, int silent,
return 0;
}
int parse_options_remount(struct super_block *sb, char *options, int silent,
struct sdcardfs_vfsmount_options *vfsopts)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
int debug;
if (!options)
return 0;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, sdcardfs_tokens, args);
switch (token) {
case Opt_debug:
debug = 1;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
vfsopts->gid = option;
break;
case Opt_mask:
if (match_int(&args[0], &option))
return 0;
vfsopts->mask = option;
break;
case Opt_multiuser:
case Opt_userid:
case Opt_fsuid:
case Opt_fsgid:
case Opt_reserved_mb:
printk( KERN_WARNING "Option \"%s\" can't be changed during remount\n", p);
break;
/* unknown option */
default:
if (!silent) {
printk( KERN_ERR "Unrecognized mount option \"%s\" "
"or missing value", p);
}
return -EINVAL;
}
}
if (debug) {
printk( KERN_INFO "sdcardfs : options - debug:%d\n", debug);
printk( KERN_INFO "sdcardfs : options - gid:%d\n", vfsopts->gid);
printk( KERN_INFO "sdcardfs : options - mask:%d\n", vfsopts->mask);
}
return 0;
}
#if 0
/*
* our custom d_alloc_root work-alike
@ -172,14 +236,15 @@ EXPORT_SYMBOL_GPL(sdcardfs_super_list);
* There is no need to lock the sdcardfs_super_info's rwsem as there is no
* way anyone can have a reference to the superblock at this point in time.
*/
static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
void *raw_data, int silent)
static int sdcardfs_read_super(struct vfsmount *mnt, struct super_block *sb,
const char *dev_name, void *raw_data, int silent)
{
int err = 0;
int debug;
struct super_block *lower_sb;
struct path lower_path;
struct sdcardfs_sb_info *sb_info;
struct sdcardfs_vfsmount_options *mnt_opt = mnt->data;
struct inode *inode;
printk(KERN_INFO "sdcardfs version 2.0\n");
@ -212,7 +277,7 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
sb_info = sb->s_fs_info;
/* parse options */
err = parse_options(sb, raw_data, silent, &debug, &sb_info->options);
err = parse_options(sb, raw_data, silent, &debug, mnt_opt, &sb_info->options);
if (err) {
printk(KERN_ERR "sdcardfs: invalid options\n");
goto out_freesbi;
@ -306,9 +371,9 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
}
/* A feature which supports mount_nodev() with options */
static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data,
int (*fill_super)(struct super_block *, const char *, void *, int))
static struct dentry *mount_nodev_with_options(struct vfsmount *mnt,
struct file_system_type *fs_type, int flags, const char *dev_name, void *data,
int (*fill_super)(struct vfsmount *, struct super_block *, const char *, void *, int))
{
int error;
@ -319,7 +384,7 @@ static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
s->s_flags = flags;
error = fill_super(s, dev_name, data, flags & MS_SILENT ? 1 : 0);
error = fill_super(mnt, s, dev_name, data, flags & MS_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(s);
return ERR_PTR(error);
@ -328,15 +393,27 @@ static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type,
return dget(s->s_root);
}
struct dentry *sdcardfs_mount(struct file_system_type *fs_type, int flags,
static struct dentry *sdcardfs_mount(struct vfsmount *mnt,
struct file_system_type *fs_type, int flags,
const char *dev_name, void *raw_data)
{
/*
* dev_name is a lower_path_name,
* raw_data is a option string.
*/
return mount_nodev_with_options(fs_type, flags, dev_name,
raw_data, sdcardfs_read_super);
return mount_nodev_with_options(mnt, fs_type, flags, dev_name,
raw_data, sdcardfs_read_super);
}
static struct dentry *sdcardfs_mount_wrn(struct file_system_type *fs_type, int flags,
const char *dev_name, void *raw_data)
{
WARN(1, "sdcardfs does not support mount. Use mount2.\n");
return ERR_PTR(-EINVAL);
}
void *sdcardfs_alloc_mnt_data(void) {
return kmalloc(sizeof(struct sdcardfs_vfsmount_options), GFP_KERNEL);
}
void sdcardfs_kill_sb(struct super_block *sb) {
@ -353,7 +430,9 @@ void sdcardfs_kill_sb(struct super_block *sb) {
static struct file_system_type sdcardfs_fs_type = {
.owner = THIS_MODULE,
.name = SDCARDFS_NAME,
.mount = sdcardfs_mount,
.mount = sdcardfs_mount_wrn,
.mount2 = sdcardfs_mount,
.alloc_mnt_data = sdcardfs_alloc_mnt_data,
.kill_sb = sdcardfs_kill_sb,
.fs_flags = 0,
};

8
fs/sdcardfs/sdcardfs.h
View file

@ -193,6 +193,14 @@ struct sdcardfs_mount_options {
unsigned int reserved_mb;
};
struct sdcardfs_vfsmount_options {
gid_t gid;
mode_t mask;
};
extern int parse_options_remount(struct super_block *sb, char *options, int silent,
struct sdcardfs_vfsmount_options *vfsopts);
/* sdcardfs super-block data in memory */
struct sdcardfs_sb_info {
struct super_block *sb;

64
fs/sdcardfs/super.c
View file

@ -108,6 +108,50 @@ static int sdcardfs_remount_fs(struct super_block *sb, int *flags, char *options
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) {
printk(KERN_ERR
"sdcardfs: remount flags 0x%x unsupported\n", *flags);
err = -EINVAL;
}
printk(KERN_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
@ -191,19 +235,24 @@ static void sdcardfs_umount_begin(struct super_block *sb)
lower_sb->s_op->umount_begin(lower_sb);
}
static int sdcardfs_show_options(struct seq_file *m, struct dentry *root)
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, ",uid=%u", opts->fs_low_uid);
seq_printf(m, ",fsuid=%u", opts->fs_low_uid);
if (opts->fs_low_gid != 0)
seq_printf(m, ",gid=%u", opts->fs_low_gid);
seq_printf(m, ",fsgid=%u", opts->fs_low_gid);
if (vfsopts->gid != 0)
seq_printf(m, ",gid=%u", vfsopts->gid);
if (opts->multiuser)
seq_printf(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->reserved_mb != 0)
seq_printf(m, ",reserved=%uMB", opts->reserved_mb);
@ -214,9 +263,12 @@ 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_options = sdcardfs_show_options,
.show_options2 = sdcardfs_show_options,
.alloc_inode = sdcardfs_alloc_inode,
.destroy_inode = sdcardfs_destroy_inode,
.drop_inode = generic_delete_inode,