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Merge branch 'overlayfs-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs into for-next

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This commit is contained in:
Al Viro
2015-02-20 04:58:52 -05:00
parent a95104fd33 4330397e4e
commit ce7b9facdf
7 changed files with 537 additions and 339 deletions
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5
fs/overlayfs/copy_up.c
View File

@@ -191,7 +191,6 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
ovl_set_timestamps(upperdentry, stat);
return err;
}
static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
@@ -385,7 +384,7 @@ int ovl_copy_up(struct dentry *dentry)
struct kstat stat;
enum ovl_path_type type = ovl_path_type(dentry);
if (type != OVL_PATH_LOWER)
if (OVL_TYPE_UPPER(type))
break;
next = dget(dentry);
@@ -394,7 +393,7 @@ int ovl_copy_up(struct dentry *dentry)
parent = dget_parent(next);
type = ovl_path_type(parent);
if (type != OVL_PATH_LOWER)
if (OVL_TYPE_UPPER(type))
break;
dput(next);

28
fs/overlayfs/dir.c
View File

@@ -118,14 +118,14 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
static int ovl_set_opaque(struct dentry *upperdentry)
{
return ovl_do_setxattr(upperdentry, ovl_opaque_xattr, "y", 1, 0);
return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
}
static void ovl_remove_opaque(struct dentry *upperdentry)
{
int err;
err = ovl_do_removexattr(upperdentry, ovl_opaque_xattr);
err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
if (err) {
pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
upperdentry->d_name.name, err);
@@ -152,7 +152,7 @@ static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
* correct link count. nlink=1 seems to pacify 'find' and
* other utilities.
*/
if (type == OVL_PATH_MERGE)
if (OVL_TYPE_MERGE(type))
stat->nlink = 1;
return 0;
@@ -506,7 +506,7 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
struct dentry *opaquedir = NULL;
int err;
if (is_dir) {
if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
opaquedir = ovl_check_empty_and_clear(dentry);
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir))
@@ -630,7 +630,7 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir)
goto out_drop_write;
type = ovl_path_type(dentry);
if (type == OVL_PATH_PURE_UPPER) {
if (OVL_TYPE_PURE_UPPER(type)) {
err = ovl_remove_upper(dentry, is_dir);
} else {
const struct cred *old_cred;
@@ -712,7 +712,7 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
/* Don't copy up directory trees */
old_type = ovl_path_type(old);
err = -EXDEV;
if ((old_type == OVL_PATH_LOWER || old_type == OVL_PATH_MERGE) && is_dir)
if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
goto out;
if (new->d_inode) {
@@ -725,25 +725,25 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
new_type = ovl_path_type(new);
err = -EXDEV;
if (!overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir)
if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
goto out;
err = 0;
if (new_type == OVL_PATH_LOWER && old_type == OVL_PATH_LOWER) {
if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
if (ovl_dentry_lower(old)->d_inode ==
ovl_dentry_lower(new)->d_inode)
goto out;
}
if (new_type != OVL_PATH_LOWER && old_type != OVL_PATH_LOWER) {
if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
if (ovl_dentry_upper(old)->d_inode ==
ovl_dentry_upper(new)->d_inode)
goto out;
}
} else {
if (ovl_dentry_is_opaque(new))
new_type = OVL_PATH_UPPER;
new_type = __OVL_PATH_UPPER;
else
new_type = OVL_PATH_PURE_UPPER;
new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
}
err = ovl_want_write(old);
@@ -763,8 +763,8 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
goto out_drop_write;
}
old_opaque = old_type != OVL_PATH_PURE_UPPER;
new_opaque = new_type != OVL_PATH_PURE_UPPER;
old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
if (old_opaque || new_opaque) {
err = -ENOMEM;
@@ -787,7 +787,7 @@ static int ovl_rename2(struct inode *olddir, struct dentry *old,
old_cred = override_creds(override_cred);
}
if (overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir) {
if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
opaquedir = ovl_check_empty_and_clear(new);
err = PTR_ERR(opaquedir);
if (IS_ERR(opaquedir)) {

12
fs/overlayfs/inode.c
View File

@@ -205,7 +205,7 @@ static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
static bool ovl_is_private_xattr(const char *name)
{
return strncmp(name, "trusted.overlay.", 14) == 0;
return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0;
}
int ovl_setxattr(struct dentry *dentry, const char *name,
@@ -238,7 +238,10 @@ out:
static bool ovl_need_xattr_filter(struct dentry *dentry,
enum ovl_path_type type)
{
return type == OVL_PATH_UPPER && S_ISDIR(dentry->d_inode->i_mode);
if ((type & (__OVL_PATH_PURE | __OVL_PATH_UPPER)) == __OVL_PATH_UPPER)
return S_ISDIR(dentry->d_inode->i_mode);
else
return false;
}
ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
@@ -299,7 +302,7 @@ int ovl_removexattr(struct dentry *dentry, const char *name)
if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
goto out_drop_write;
if (type == OVL_PATH_LOWER) {
if (!OVL_TYPE_UPPER(type)) {
err = vfs_getxattr(realpath.dentry, name, NULL, 0);
if (err < 0)
goto out_drop_write;
@@ -321,7 +324,7 @@ out:
static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
struct dentry *realdentry)
{
if (type != OVL_PATH_LOWER)
if (OVL_TYPE_UPPER(type))
return false;
if (special_file(realdentry->d_inode->i_mode))
@@ -430,5 +433,4 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
}
return inode;
}

18
fs/overlayfs/overlayfs.h
View File

@@ -12,13 +12,20 @@
struct ovl_entry;
enum ovl_path_type {
OVL_PATH_PURE_UPPER,
OVL_PATH_UPPER,
OVL_PATH_MERGE,
OVL_PATH_LOWER,
__OVL_PATH_PURE = (1 << 0),
__OVL_PATH_UPPER = (1 << 1),
__OVL_PATH_MERGE = (1 << 2),
};
extern const char *ovl_opaque_xattr;
#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
#define OVL_TYPE_PURE_UPPER(type) ((type) & __OVL_PATH_PURE)
#define OVL_TYPE_MERGE_OR_LOWER(type) \
(OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type))
#define OVL_XATTR_PRE_NAME "trusted.overlay."
#define OVL_XATTR_PRE_LEN 16
#define OVL_XATTR_OPAQUE OVL_XATTR_PRE_NAME"opaque"
static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
{
@@ -130,6 +137,7 @@ 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);
int ovl_path_next(int idx, 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);

181
fs/overlayfs/readdir.c
View File

@@ -24,7 +24,6 @@ struct ovl_cache_entry {
struct list_head l_node;
struct rb_node node;
bool is_whiteout;
bool is_cursor;
char name[];
};
@@ -40,6 +39,7 @@ struct ovl_readdir_data {
struct rb_root root;
struct list_head *list;
struct list_head middle;
struct dentry *dir;
int count;
int err;
};
@@ -48,7 +48,7 @@ struct ovl_dir_file {
bool is_real;
bool is_upper;
struct ovl_dir_cache *cache;
struct ovl_cache_entry cursor;
struct list_head *cursor;
struct file *realfile;
struct file *upperfile;
};
@@ -79,23 +79,49 @@ static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root,
return NULL;
}
static struct ovl_cache_entry *ovl_cache_entry_new(const char *name, int len,
static struct ovl_cache_entry *ovl_cache_entry_new(struct dentry *dir,
const char *name, int len,
u64 ino, unsigned int d_type)
{
struct ovl_cache_entry *p;
size_t size = offsetof(struct ovl_cache_entry, name[len + 1]);
p = kmalloc(size, GFP_KERNEL);
if (p) {
memcpy(p->name, name, len);
p->name[len] = '\0';
p->len = len;
p->type = d_type;
p->ino = ino;
p->is_whiteout = false;
p->is_cursor = false;
}
if (!p)
return NULL;
memcpy(p->name, name, len);
p->name[len] = '\0';
p->len = len;
p->type = d_type;
p->ino = ino;
p->is_whiteout = false;
if (d_type == DT_CHR) {
struct dentry *dentry;
const struct cred *old_cred;
struct cred *override_cred;
override_cred = prepare_creds();
if (!override_cred) {
kfree(p);
return NULL;
}
/*
* CAP_DAC_OVERRIDE for lookup
*/
cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
old_cred = override_creds(override_cred);
dentry = lookup_one_len(name, dir, len);
if (!IS_ERR(dentry)) {
p->is_whiteout = ovl_is_whiteout(dentry);
dput(dentry);
}
revert_creds(old_cred);
put_cred(override_cred);
}
return p;
}
@@ -122,7 +148,7 @@ static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
return 0;
}
p = ovl_cache_entry_new(name, len, ino, d_type);
p = ovl_cache_entry_new(rdd->dir, name, len, ino, d_type);
if (p == NULL)
return -ENOMEM;
@@ -143,7 +169,7 @@ static int ovl_fill_lower(struct ovl_readdir_data *rdd,
if (p) {
list_move_tail(&p->l_node, &rdd->middle);
} else {
p = ovl_cache_entry_new(name, namelen, ino, d_type);
p = ovl_cache_entry_new(rdd->dir, name, namelen, ino, d_type);
if (p == NULL)
rdd->err = -ENOMEM;
else
@@ -168,7 +194,6 @@ static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry)
{
struct ovl_dir_cache *cache = od->cache;
list_del_init(&od->cursor.l_node);
WARN_ON(cache->refcount <= 0);
cache->refcount--;
if (!cache->refcount) {
@@ -204,6 +229,7 @@ static inline int ovl_dir_read(struct path *realpath,
if (IS_ERR(realfile))
return PTR_ERR(realfile);
rdd->dir = realpath->dentry;
rdd->ctx.pos = 0;
do {
rdd->count = 0;
@@ -227,108 +253,58 @@ static void ovl_dir_reset(struct file *file)
if (cache && ovl_dentry_version_get(dentry) != cache->version) {
ovl_cache_put(od, dentry);
od->cache = NULL;
od->cursor = NULL;
}
WARN_ON(!od->is_real && type != OVL_PATH_MERGE);
if (od->is_real && type == OVL_PATH_MERGE)
WARN_ON(!od->is_real && !OVL_TYPE_MERGE(type));
if (od->is_real && OVL_TYPE_MERGE(type))
od->is_real = false;
}
static int ovl_dir_mark_whiteouts(struct dentry *dir,
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_DAC_OVERRIDE for lookup
*/
cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
old_cred = override_creds(override_cred);
mutex_lock(&dir->d_inode->i_mutex);
list_for_each_entry(p, rdd->list, l_node) {
if (p->is_cursor)
continue;
if (p->type != DT_CHR)
continue;
dentry = lookup_one_len(p->name, dir, p->len);
if (IS_ERR(dentry))
continue;
p->is_whiteout = ovl_is_whiteout(dentry);
dput(dentry);
}
mutex_unlock(&dir->d_inode->i_mutex);
revert_creds(old_cred);
put_cred(override_cred);
return 0;
}
static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
{
int err;
struct path lowerpath;
struct path upperpath;
struct path realpath;
struct ovl_readdir_data rdd = {
.ctx.actor = ovl_fill_merge,
.list = list,
.root = RB_ROOT,
.is_merge = false,
};
int idx, next;
ovl_path_lower(dentry, &lowerpath);
ovl_path_upper(dentry, &upperpath);
for (idx = 0; idx != -1; idx = next) {
next = ovl_path_next(idx, dentry, &realpath);
if (upperpath.dentry) {
err = ovl_dir_read(&upperpath, &rdd);
if (err)
goto out;
if (lowerpath.dentry) {
err = ovl_dir_mark_whiteouts(upperpath.dentry, &rdd);
if (next != -1) {
err = ovl_dir_read(&realpath, &rdd);
if (err)
goto out;
break;
} else {
/*
* Insert lowest layer entries before upper ones, this
* allows offsets to be reasonably constant
*/
list_add(&rdd.middle, rdd.list);
rdd.is_merge = true;
err = ovl_dir_read(&realpath, &rdd);
list_del(&rdd.middle);
}
}
if (lowerpath.dentry) {
/*
* Insert lowerpath entries before upperpath ones, this allows
* offsets to be reasonably constant
*/
list_add(&rdd.middle, rdd.list);
rdd.is_merge = true;
err = ovl_dir_read(&lowerpath, &rdd);
list_del(&rdd.middle);
}
out:
return err;
}
static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos)
{
struct ovl_cache_entry *p;
struct list_head *p;
loff_t off = 0;
list_for_each_entry(p, &od->cache->entries, l_node) {
if (p->is_cursor)
continue;
list_for_each(p, &od->cache->entries) {
if (off >= pos)
break;
off++;
}
list_move_tail(&od->cursor.l_node, &p->l_node);
/* Cursor is safe since the cache is stable */
od->cursor = p;
}
static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
@@ -367,6 +343,7 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
{
struct ovl_dir_file *od = file->private_data;
struct dentry *dentry = file->f_path.dentry;
struct ovl_cache_entry *p;
if (!ctx->pos)
ovl_dir_reset(file);
@@ -385,19 +362,13 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
ovl_seek_cursor(od, ctx->pos);
}
while (od->cursor.l_node.next != &od->cache->entries) {
struct ovl_cache_entry *p;
p = list_entry(od->cursor.l_node.next, struct ovl_cache_entry, l_node);
/* Skip cursors */
if (!p->is_cursor) {
if (!p->is_whiteout) {
if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
break;
}
ctx->pos++;
}
list_move(&od->cursor.l_node, &p->l_node);
while (od->cursor != &od->cache->entries) {
p = list_entry(od->cursor, struct ovl_cache_entry, l_node);
if (!p->is_whiteout)
if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
break;
od->cursor = p->l_node.next;
ctx->pos++;
}
return 0;
}
@@ -452,7 +423,7 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
/*
* Need to check if we started out being a lower dir, but got copied up
*/
if (!od->is_upper && ovl_path_type(dentry) != OVL_PATH_LOWER) {
if (!od->is_upper && OVL_TYPE_UPPER(ovl_path_type(dentry))) {
struct inode *inode = file_inode(file);
realfile = lockless_dereference(od->upperfile);
@@ -516,11 +487,9 @@ static int ovl_dir_open(struct inode *inode, struct file *file)
kfree(od);
return PTR_ERR(realfile);
}
INIT_LIST_HEAD(&od->cursor.l_node);
od->realfile = realfile;
od->is_real = (type != OVL_PATH_MERGE);
od->is_upper = (type != OVL_PATH_LOWER);
od->cursor.is_cursor = true;
od->is_real = !OVL_TYPE_MERGE(type);
od->is_upper = OVL_TYPE_UPPER(type);
file->private_data = od;
return 0;

604
fs/overlayfs/super.c
View File

@@ -35,7 +35,8 @@ struct ovl_config {
/* private information held for overlayfs's superblock */
struct ovl_fs {
struct vfsmount *upper_mnt;
struct vfsmount *lower_mnt;
unsigned numlower;
struct vfsmount **lower_mnt;
struct dentry *workdir;
long lower_namelen;
/* pathnames of lower and upper dirs, for show_options */
@@ -47,7 +48,6 @@ struct ovl_dir_cache;
/* private information held for every overlayfs dentry */
struct ovl_entry {
struct dentry *__upperdentry;
struct dentry *lowerdentry;
struct ovl_dir_cache *cache;
union {
struct {
@@ -56,30 +56,36 @@ struct ovl_entry {
};
struct rcu_head rcu;
};
unsigned numlower;
struct path lowerstack[];
};
const char *ovl_opaque_xattr = "trusted.overlay.opaque";
#define OVL_MAX_STACK 500
static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
{
return oe->numlower ? oe->lowerstack[0].dentry : NULL;
}
enum ovl_path_type ovl_path_type(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
enum ovl_path_type type = 0;
if (oe->__upperdentry) {
if (oe->lowerdentry) {
type = __OVL_PATH_UPPER;
if (oe->numlower) {
if (S_ISDIR(dentry->d_inode->i_mode))
return OVL_PATH_MERGE;
else
return OVL_PATH_UPPER;
} else {
if (oe->opaque)
return OVL_PATH_UPPER;
else
return OVL_PATH_PURE_UPPER;
type |= __OVL_PATH_MERGE;
} else if (!oe->opaque) {
type |= __OVL_PATH_PURE;
}
} else {
return OVL_PATH_LOWER;
if (oe->numlower > 1)
type |= __OVL_PATH_MERGE;
}
return type;
}
static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
@@ -98,10 +104,9 @@ void ovl_path_upper(struct dentry *dentry, struct path *path)
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)
if (!OVL_TYPE_UPPER(type))
ovl_path_lower(dentry, path);
else
ovl_path_upper(dentry, path);
@@ -120,7 +125,7 @@ struct dentry *ovl_dentry_lower(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
return oe->lowerdentry;
return __ovl_dentry_lower(oe);
}
struct dentry *ovl_dentry_real(struct dentry *dentry)
@@ -130,7 +135,7 @@ struct dentry *ovl_dentry_real(struct dentry *dentry)
realdentry = ovl_upperdentry_dereference(oe);
if (!realdentry)
realdentry = oe->lowerdentry;
realdentry = __ovl_dentry_lower(oe);
return realdentry;
}
@@ -143,7 +148,7 @@ struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper)
if (realdentry) {
*is_upper = true;
} else {
realdentry = oe->lowerdentry;
realdentry = __ovl_dentry_lower(oe);
*is_upper = false;
}
return realdentry;
@@ -165,11 +170,9 @@ void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
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;
*path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
}
int ovl_want_write(struct dentry *dentry)
@@ -249,7 +252,7 @@ static bool ovl_is_opaquedir(struct dentry *dentry)
if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr)
return false;
res = inode->i_op->getxattr(dentry, ovl_opaque_xattr, &val, 1);
res = inode->i_op->getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
if (res == 1 && val == 'y')
return true;
@@ -261,8 +264,11 @@ static void ovl_dentry_release(struct dentry *dentry)
struct ovl_entry *oe = dentry->d_fsdata;
if (oe) {
unsigned int i;
dput(oe->__upperdentry);
dput(oe->lowerdentry);
for (i = 0; i < oe->numlower; i++)
dput(oe->lowerstack[i].dentry);
kfree_rcu(oe, rcu);
}
}
@@ -271,9 +277,15 @@ static const struct dentry_operations ovl_dentry_operations = {
.d_release = ovl_dentry_release,
};
static struct ovl_entry *ovl_alloc_entry(void)
static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
{
return kzalloc(sizeof(struct ovl_entry), GFP_KERNEL);
size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
if (oe)
oe->numlower = numlower;
return oe;
}
static inline struct dentry *ovl_lookup_real(struct dentry *dir,
@@ -295,82 +307,154 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir,
return dentry;
}
/*
* Returns next layer in stack starting from top.
* Returns -1 if this is the last layer.
*/
int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
{
struct ovl_entry *oe = dentry->d_fsdata;
BUG_ON(idx < 0);
if (idx == 0) {
ovl_path_upper(dentry, path);
if (path->dentry)
return oe->numlower ? 1 : -1;
idx++;
}
BUG_ON(idx > oe->numlower);
*path = oe->lowerstack[idx - 1];
return (idx < oe->numlower) ? idx + 1 : -1;
}
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 ovl_entry *poe = dentry->d_parent->d_fsdata;
struct path *stack = NULL;
struct dentry *upperdir, *upperdentry = NULL;
unsigned int ctr = 0;
struct inode *inode = NULL;
bool upperopaque = false;
struct dentry *this, *prev = NULL;
unsigned int i;
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);
upperdir = ovl_upperdentry_dereference(poe);
if (upperdir) {
upperdentry = ovl_lookup_real(upperdir, &dentry->d_name);
err = PTR_ERR(upperdentry);
if (IS_ERR(upperdentry))
goto out_put_dir;
this = ovl_lookup_real(upperdir, &dentry->d_name);
err = PTR_ERR(this);
if (IS_ERR(this))
goto out;
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 (this) {
if (ovl_is_whiteout(this)) {
dput(this);
this = NULL;
upperopaque = true;
} else if (poe->numlower && ovl_is_opaquedir(this)) {
upperopaque = 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;
upperdentry = prev = this;
}
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 (!upperopaque && poe->numlower) {
err = -ENOMEM;
stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL);
if (!stack)
goto out_put_upper;
}
if (lowerdentry || upperdentry) {
for (i = 0; !upperopaque && i < poe->numlower; i++) {
bool opaque = false;
struct path lowerpath = poe->lowerstack[i];
this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
err = PTR_ERR(this);
if (IS_ERR(this)) {
/*
* If it's positive, then treat ENAMETOOLONG as ENOENT.
*/
if (err == -ENAMETOOLONG && (upperdentry || ctr))
continue;
goto out_put;
}
if (!this)
continue;
if (ovl_is_whiteout(this)) {
dput(this);
break;
}
/*
* Only makes sense to check opaque dir if this is not the
* lowermost layer.
*/
if (i < poe->numlower - 1 && ovl_is_opaquedir(this))
opaque = true;
if (prev && (!S_ISDIR(prev->d_inode->i_mode) ||
!S_ISDIR(this->d_inode->i_mode))) {
/*
* FIXME: check for upper-opaqueness maybe better done
* in remove code.
*/
if (prev == upperdentry)
upperopaque = true;
dput(this);
break;
}
/*
* If this is a non-directory then stop here.
*/
if (!S_ISDIR(this->d_inode->i_mode))
opaque = true;
stack[ctr].dentry = this;
stack[ctr].mnt = lowerpath.mnt;
ctr++;
prev = this;
if (opaque)
break;
}
oe = ovl_alloc_entry(ctr);
err = -ENOMEM;
if (!oe)
goto out_put;
if (upperdentry || ctr) {
struct dentry *realdentry;
realdentry = upperdentry ? upperdentry : lowerdentry;
realdentry = upperdentry ? upperdentry : stack[0].dentry;
err = -ENOMEM;
inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode,
oe);
if (!inode)
goto out_dput;
goto out_free_oe;
ovl_copyattr(realdentry->d_inode, inode);
}
oe->opaque = upperopaque;
oe->__upperdentry = upperdentry;
oe->lowerdentry = lowerdentry;
memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
kfree(stack);
dentry->d_fsdata = oe;
d_add(dentry, inode);
return NULL;
out_dput:
dput(lowerdentry);
out_dput_upper:
dput(upperdentry);
out_put_dir:
out_free_oe:
kfree(oe);
out_put:
for (i = 0; i < ctr; i++)
dput(stack[i].dentry);
kfree(stack);
out_put_upper:
dput(upperdentry);
out:
return ERR_PTR(err);
}
@@ -383,10 +467,12 @@ struct file *ovl_path_open(struct path *path, int flags)
static void ovl_put_super(struct super_block *sb)
{
struct ovl_fs *ufs = sb->s_fs_info;
unsigned i;
dput(ufs->workdir);
mntput(ufs->upper_mnt);
mntput(ufs->lower_mnt);
for (i = 0; i < ufs->numlower; i++)
mntput(ufs->lower_mnt[i]);
kfree(ufs->config.lowerdir);
kfree(ufs->config.upperdir);
@@ -400,7 +486,7 @@ static void ovl_put_super(struct super_block *sb)
* @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.
* filesystem pass the statfs to the upper filesystem (if it exists)
*/
static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
{
@@ -409,7 +495,7 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
struct path path;
int err;
ovl_path_upper(root_dentry, &path);
ovl_path_real(root_dentry, &path);
err = vfs_statfs(&path, buf);
if (!err) {
@@ -432,8 +518,21 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
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);
if (ufs->config.upperdir) {
seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
seq_printf(m, ",workdir=%s", ufs->config.workdir);
}
return 0;
}
static int ovl_remount(struct super_block *sb, int *flags, char *data)
{
struct ovl_fs *ufs = sb->s_fs_info;
if (!(*flags & MS_RDONLY) &&
(!ufs->upper_mnt || (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY)))
return -EROFS;
return 0;
}
@@ -441,6 +540,7 @@ static const struct super_operations ovl_super_operations = {
.put_super = ovl_put_super,
.statfs = ovl_statfs,
.show_options = ovl_show_options,
.remount_fs = ovl_remount,
};
enum {
@@ -585,24 +685,6 @@ static void ovl_unescape(char *s)
}
}
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;
@@ -622,6 +704,75 @@ static bool ovl_is_allowed_fs_type(struct dentry *root)
return true;
}
static int ovl_mount_dir_noesc(const char *name, struct path *path)
{
int err = -EINVAL;
if (!*name) {
pr_err("overlayfs: empty lowerdir\n");
goto out;
}
err = kern_path(name, LOOKUP_FOLLOW, path);
if (err) {
pr_err("overlayfs: failed to resolve '%s': %i\n", name, err);
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 (!S_ISDIR(path->dentry->d_inode->i_mode)) {
pr_err("overlayfs: '%s' not a directory\n", name);
goto out_put;
}
return 0;
out_put:
path_put(path);
out:
return err;
}
static int ovl_mount_dir(const char *name, struct path *path)
{
int err = -ENOMEM;
char *tmp = kstrdup(name, GFP_KERNEL);
if (tmp) {
ovl_unescape(tmp);
err = ovl_mount_dir_noesc(tmp, path);
kfree(tmp);
}
return err;
}
static int ovl_lower_dir(const char *name, struct path *path, long *namelen,
int *stack_depth)
{
int err;
struct kstatfs statfs;
err = ovl_mount_dir_noesc(name, path);
if (err)
goto out;
err = vfs_statfs(path, &statfs);
if (err) {
pr_err("overlayfs: statfs failed on '%s'\n", name);
goto out_put;
}
*namelen = max(*namelen, statfs.f_namelen);
*stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
return 0;
out_put:
path_put(path);
out:
return err;
}
/* Workdir should not be subdir of upperdir and vice versa */
static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
{
@@ -634,16 +785,39 @@ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
return ok;
}
static unsigned int ovl_split_lowerdirs(char *str)
{
unsigned int ctr = 1;
char *s, *d;
for (s = d = str;; s++, d++) {
if (*s == '\\') {
s++;
} else if (*s == ':') {
*d = '\0';
ctr++;
continue;
}
*d = *s;
if (!*s)
break;
}
return ctr;
}
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 path upperpath = { NULL, NULL };
struct path workpath = { NULL, NULL };
struct dentry *root_dentry;
struct ovl_entry *oe;
struct ovl_fs *ufs;
struct kstatfs statfs;
struct path *stack = NULL;
char *lowertmp;
char *lower;
unsigned int numlower;
unsigned int stacklen = 0;
unsigned int i;
int err;
err = -ENOMEM;
@@ -655,123 +829,135 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
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");
if (!ufs->config.lowerdir) {
pr_err("overlayfs: missing 'lowerdir'\n");
goto out_free_config;
}
sb->s_stack_depth = 0;
if (ufs->config.upperdir) {
/* FIXME: workdir is not needed for a R/O mount */
if (!ufs->config.workdir) {
pr_err("overlayfs: missing 'workdir'\n");
goto out_free_config;
}
err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
if (err)
goto out_free_config;
err = ovl_mount_dir(ufs->config.workdir, &workpath);
if (err)
goto out_put_upperpath;
err = -EINVAL;
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;
}
sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
}
err = -ENOMEM;
lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
if (!lowertmp)
goto out_put_workpath;
err = -EINVAL;
stacklen = ovl_split_lowerdirs(lowertmp);
if (stacklen > OVL_MAX_STACK)
goto out_free_lowertmp;
stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
if (!stack)
goto out_free_lowertmp;
lower = lowertmp;
for (numlower = 0; numlower < stacklen; numlower++) {
err = ovl_lower_dir(lower, &stack[numlower],
&ufs->lower_namelen, &sb->s_stack_depth);
if (err)
goto out_put_lowerpath;
lower = strchr(lower, '\0') + 1;
}
err = -EINVAL;
sb->s_stack_depth++;
if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
pr_err("overlayfs: maximum fs stacking depth exceeded\n");
goto out_put_lowerpath;
}
if (ufs->config.upperdir) {
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_lowerpath;
}
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_upper_mnt;
}
}
err = -ENOMEM;
oe = ovl_alloc_entry();
if (oe == NULL)
goto out_free_config;
ufs->lower_mnt = kcalloc(numlower, sizeof(struct vfsmount *), GFP_KERNEL);
if (ufs->lower_mnt == NULL)
goto out_put_workdir;
for (i = 0; i < numlower; i++) {
struct vfsmount *mnt = clone_private_mount(&stack[i]);
err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
if (err)
goto out_free_oe;
err = PTR_ERR(mnt);
if (IS_ERR(mnt)) {
pr_err("overlayfs: failed to clone lowerpath\n");
goto out_put_lower_mnt;
}
/*
* Make lower_mnt R/O. That way fchmod/fchown on lower file
* will fail instead of modifying lower fs.
*/
mnt->mnt_flags |= MNT_READONLY;
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;
ufs->lower_mnt[ufs->numlower] = mnt;
ufs->numlower++;
}
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)
/* If the upper fs is r/o or nonexistent, we mark overlayfs r/o too */
if (!ufs->upper_mnt || (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;
oe = ovl_alloc_entry(numlower);
if (!oe)
goto out_put_lower_mnt;
root_dentry = d_make_root(root_inode);
root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe));
if (!root_dentry)
goto out_put_workdir;
goto out_free_oe;
mntput(upperpath.mnt);
mntput(lowerpath.mnt);
for (i = 0; i < numlower; i++)
mntput(stack[i].mnt);
path_put(&workpath);
kfree(lowertmp);
oe->__upperdentry = upperpath.dentry;
oe->lowerdentry = lowerpath.dentry;
for (i = 0; i < numlower; i++) {
oe->lowerstack[i].dentry = stack[i].dentry;
oe->lowerstack[i].mnt = ufs->lower_mnt[i];
}
root_dentry->d_fsdata = oe;
@@ -782,20 +968,26 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
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_put_lower_mnt:
for (i = 0; i < ufs->numlower; i++)
mntput(ufs->lower_mnt[i]);
kfree(ufs->lower_mnt);
out_put_workdir:
dput(ufs->workdir);
out_put_upper_mnt:
mntput(ufs->upper_mnt);
out_put_lowerpath:
for (i = 0; i < numlower; i++)
path_put(&stack[i]);
kfree(stack);
out_free_lowertmp:
kfree(lowertmp);
out_put_workpath:
path_put(&workpath);
out_put_upperpath:
path_put(&upperpath);
out_free_config:
kfree(ufs->config.lowerdir);
kfree(ufs->config.upperdir);