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mcoverlayfs: support mount options(nocopyupw, nofscheck)

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This commit is contained in:
Yoichi Umezawa
2015-11-25 15:34:58 +09:00
parent 544971d665
commit 65dda3f24e
3 changed files with 82 additions and 31 deletions
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26
executer/kernel/mcoverlayfs/inode.c
View File

@ -345,20 +345,22 @@ static int ovl_dentry_open(struct dentry *dentry, struct file *file,
bool want_write = false;
type = ovl_path_real(dentry, &realpath);
if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) {
want_write = true;
err = ovl_want_write(dentry);
if (err)
goto out;
if (!ovl_is_nocopyupw(dentry)) {
if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) {
want_write = true;
err = ovl_want_write(dentry);
if (err)
goto out;
if (file->f_flags & O_TRUNC)
err = ovl_copy_up_last(dentry, NULL, true);
else
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
if (file->f_flags & O_TRUNC)
err = ovl_copy_up_last(dentry, NULL, true);
else
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
ovl_path_upper(dentry, &realpath);
ovl_path_upper(dentry, &realpath);
}
}
err = vfs_open(&realpath, file, cred);

1
executer/kernel/mcoverlayfs/overlayfs.h
View File

@ -131,6 +131,7 @@ static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
return err;
}
bool ovl_is_nocopyupw(struct dentry *dentry);
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);

86
executer/kernel/mcoverlayfs/super.c
View File

@ -24,12 +24,22 @@ MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Overlay filesystem");
MODULE_LICENSE("GPL");
#define OVERLAYFS_SUPER_MAGIC 0x794c7630
#define MCOVERLAYFS_SUPER_MAGIC 0x4d634f56
enum ovl_opt_bit {
__OVL_OPT_DEFAULT = 0,
__OVL_OPT_NOCOPYUPW = (1 << 0),
__OVL_OPT_NOFSCHECK = (1 << 1),
};
#define OVL_OPT_NOCOPYUPW(opt) ((opt) & __OVL_OPT_NOCOPYUPW)
#define OVL_OPT_NOFSCHECK(opt) ((opt) & __OVL_OPT_NOFSCHECK)
struct ovl_config {
char *lowerdir;
char *upperdir;
char *workdir;
unsigned opt;
};
/* private information held for overlayfs's superblock */
@ -62,6 +72,16 @@ struct ovl_entry {
#define OVL_MAX_STACK 500
bool ovl_is_nocopyupw(struct dentry *dentry)
{
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
if (OVL_OPT_NOCOPYUPW(ofs->config.opt))
return true;
return false;
}
static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
{
return oe->numlower ? oe->lowerstack[0].dentry : NULL;
@ -500,7 +520,7 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
err = vfs_statfs(&path, buf);
if (!err) {
buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen);
buf->f_type = OVERLAYFS_SUPER_MAGIC;
buf->f_type = MCOVERLAYFS_SUPER_MAGIC;
}
return err;
@ -522,6 +542,12 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
seq_printf(m, ",workdir=%s", ufs->config.workdir);
}
if (OVL_OPT_NOCOPYUPW(ufs->config.opt)) {
seq_printf(m, ",nocopyupw");
}
if (OVL_OPT_NOFSCHECK(ufs->config.opt)) {
seq_printf(m, ",nofscheck");
}
return 0;
}
@ -546,6 +572,8 @@ enum {
OPT_LOWERDIR,
OPT_UPPERDIR,
OPT_WORKDIR,
OPT_NOCOPYUPW,
OPT_NOFSCHECK,
OPT_ERR,
};
@ -553,6 +581,8 @@ static const match_table_t ovl_tokens = {
{OPT_LOWERDIR, "lowerdir=%s"},
{OPT_UPPERDIR, "upperdir=%s"},
{OPT_WORKDIR, "workdir=%s"},
{OPT_NOCOPYUPW, "nocopyupw"},
{OPT_NOFSCHECK, "nofscheck"},
{OPT_ERR, NULL}
};
@ -583,6 +613,8 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
{
char *p;
config->opt = __OVL_OPT_DEFAULT;
while ((p = ovl_next_opt(&opt)) != NULL) {
int token;
substring_t args[MAX_OPT_ARGS];
@ -613,6 +645,14 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
return -ENOMEM;
break;
case OPT_NOCOPYUPW:
config->opt = config->opt | __OVL_OPT_NOCOPYUPW;
break;
case OPT_NOFSCHECK:
config->opt = config->opt | __OVL_OPT_NOFSCHECK;
break;
default:
pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p);
return -EINVAL;
@ -713,7 +753,7 @@ static bool ovl_is_allowed_fs_type(struct dentry *root)
return true;
}
static int ovl_mount_dir_noesc(const char *name, struct path *path)
static int ovl_mount_dir_noesc(const char *name, struct path *path, unsigned opt)
{
int err = -EINVAL;
@ -727,9 +767,11 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path)
goto out;
}
err = -EINVAL;
if (!ovl_is_allowed_fs_type(path->dentry)) {
pr_err("overlayfs: filesystem on '%s' not supported\n", name);
goto out_put;
if (!OVL_OPT_NOFSCHECK(opt)) {
if (!ovl_is_allowed_fs_type(path->dentry)) {
pr_err("overlayfs: filesystem on '%s' not supported\n", name);
goto out_put;
}
}
if (!S_ISDIR(path->dentry->d_inode->i_mode)) {
pr_err("overlayfs: '%s' not a directory\n", name);
@ -743,26 +785,26 @@ out:
return err;
}
static int ovl_mount_dir(const char *name, struct path *path)
static int ovl_mount_dir(const char *name, struct path *path, unsigned opt)
{
int err = -ENOMEM;
char *tmp = kstrdup(name, GFP_KERNEL);
if (tmp) {
ovl_unescape(tmp);
err = ovl_mount_dir_noesc(tmp, path);
err = ovl_mount_dir_noesc(tmp, path, opt);
kfree(tmp);
}
return err;
}
static int ovl_lower_dir(const char *name, struct path *path, long *namelen,
int *stack_depth)
int *stack_depth, unsigned opt)
{
int err;
struct kstatfs statfs;
err = ovl_mount_dir_noesc(name, path);
err = ovl_mount_dir_noesc(name, path, opt);
if (err)
goto out;
@ -851,7 +893,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
goto out_free_config;
}
err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
err = ovl_mount_dir(ufs->config.upperdir, &upperpath, ufs->config.opt);
if (err)
goto out_free_config;
@ -862,7 +904,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
goto out_put_upperpath;
}
err = ovl_mount_dir(ufs->config.workdir, &workpath);
err = ovl_mount_dir(ufs->config.workdir, &workpath, ufs->config.opt);
if (err)
goto out_put_upperpath;
@ -900,7 +942,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
lower = lowertmp;
for (numlower = 0; numlower < stacklen; numlower++) {
err = ovl_lower_dir(lower, &stack[numlower],
&ufs->lower_namelen, &sb->s_stack_depth);
&ufs->lower_namelen, &sb->s_stack_depth,
ufs->config.opt);
if (err)
goto out_put_lowerpath;
@ -948,15 +991,20 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
* Make lower_mnt R/O. That way fchmod/fchown on lower file
* will fail instead of modifying lower fs.
*/
mnt->mnt_flags |= MNT_READONLY;
if (!OVL_OPT_NOCOPYUPW(ufs->config.opt)) {
mnt->mnt_flags |= MNT_READONLY;
}
ufs->lower_mnt[ufs->numlower] = mnt;
ufs->numlower++;
}
/* If the upper fs is nonexistent, we mark overlayfs r/o too */
if (!ufs->upper_mnt)
sb->s_flags |= MS_RDONLY;
if (!ufs->upper_mnt) {
if (!OVL_OPT_NOCOPYUPW(ufs->config.opt)) {
sb->s_flags |= MS_RDONLY;
}
}
sb->s_d_op = &ovl_dentry_operations;
@ -983,7 +1031,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
root_dentry->d_fsdata = oe;
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
sb->s_magic = MCOVERLAYFS_SUPER_MAGIC;
sb->s_op = &ovl_super_operations;
sb->s_root = root_dentry;
sb->s_fs_info = ufs;
@ -1026,11 +1074,11 @@ static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
static struct file_system_type ovl_fs_type = {
.owner = THIS_MODULE,
.name = "overlay",
.name = "mcoverlay",
.mount = ovl_mount,
.kill_sb = kill_anon_super,
};
MODULE_ALIAS_FS("overlay");
MODULE_ALIAS_FS("mcoverlay");
static int __init ovl_init(void)
{