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Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c211
1 files changed, 106 insertions, 105 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 5a4438445bf7..d18deb4c410b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -236,6 +236,7 @@ static struct mount *alloc_vfsmnt(const char *name)
INIT_LIST_HEAD(&mnt->mnt_slave_list);
INIT_LIST_HEAD(&mnt->mnt_slave);
INIT_HLIST_NODE(&mnt->mnt_mp_list);
+ INIT_LIST_HEAD(&mnt->mnt_umounting);
init_fs_pin(&mnt->mnt_umount, drop_mountpoint);
}
return mnt;
@@ -274,7 +275,7 @@ int __mnt_is_readonly(struct vfsmount *mnt)
{
if (mnt->mnt_flags & MNT_READONLY)
return 1;
- if (mnt->mnt_sb->s_flags & MS_RDONLY)
+ if (sb_rdonly(mnt->mnt_sb))
return 1;
return 0;
}
@@ -430,13 +431,18 @@ int __mnt_want_write_file(struct file *file)
}
/**
- * mnt_want_write_file - get write access to a file's mount
+ * mnt_want_write_file_path - get write access to a file's mount
* @file: the file who's mount on which to take a write
*
* This is like mnt_want_write, but it takes a file and can
* do some optimisations if the file is open for write already
+ *
+ * Called by the vfs for cases when we have an open file at hand, but will do an
+ * inode operation on it (important distinction for files opened on overlayfs,
+ * since the file operations will come from the real underlying file, while
+ * inode operations come from the overlay).
*/
-int mnt_want_write_file(struct file *file)
+int mnt_want_write_file_path(struct file *file)
{
int ret;
@@ -446,6 +452,55 @@ int mnt_want_write_file(struct file *file)
sb_end_write(file->f_path.mnt->mnt_sb);
return ret;
}
+
+static inline int may_write_real(struct file *file)
+{
+ struct dentry *dentry = file->f_path.dentry;
+ struct dentry *upperdentry;
+
+ /* Writable file? */
+ if (file->f_mode & FMODE_WRITER)
+ return 0;
+
+ /* Not overlayfs? */
+ if (likely(!(dentry->d_flags & DCACHE_OP_REAL)))
+ return 0;
+
+ /* File refers to upper, writable layer? */
+ upperdentry = d_real(dentry, NULL, 0, D_REAL_UPPER);
+ if (upperdentry &&
+ (file_inode(file) == d_inode(upperdentry) ||
+ file_inode(file) == d_inode(dentry)))
+ return 0;
+
+ /* Lower layer: can't write to real file, sorry... */
+ return -EPERM;
+}
+
+/**
+ * mnt_want_write_file - get write access to a file's mount
+ * @file: the file who's mount on which to take a write
+ *
+ * This is like mnt_want_write, but it takes a file and can
+ * do some optimisations if the file is open for write already
+ *
+ * Mostly called by filesystems from their ioctl operation before performing
+ * modification. On overlayfs this needs to check if the file is on a read-only
+ * lower layer and deny access in that case.
+ */
+int mnt_want_write_file(struct file *file)
+{
+ int ret;
+
+ ret = may_write_real(file);
+ if (!ret) {
+ sb_start_write(file_inode(file)->i_sb);
+ ret = __mnt_want_write_file(file);
+ if (ret)
+ sb_end_write(file_inode(file)->i_sb);
+ }
+ return ret;
+}
EXPORT_SYMBOL_GPL(mnt_want_write_file);
/**
@@ -483,10 +538,16 @@ void __mnt_drop_write_file(struct file *file)
__mnt_drop_write(file->f_path.mnt);
}
-void mnt_drop_write_file(struct file *file)
+void mnt_drop_write_file_path(struct file *file)
{
mnt_drop_write(file->f_path.mnt);
}
+
+void mnt_drop_write_file(struct file *file)
+{
+ __mnt_drop_write(file->f_path.mnt);
+ sb_end_write(file_inode(file)->i_sb);
+}
EXPORT_SYMBOL(mnt_drop_write_file);
static int mnt_make_readonly(struct mount *mnt)
@@ -970,7 +1031,7 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
if (!mnt)
return ERR_PTR(-ENOMEM);
- if (flags & MS_KERNMOUNT)
+ if (flags & SB_KERNMOUNT)
mnt->mnt.mnt_flags = MNT_INTERNAL;
root = mount_fs(type, flags, name, data);
@@ -1002,7 +1063,7 @@ vfs_submount(const struct dentry *mountpoint, struct file_system_type *type,
if (mountpoint->d_sb->s_user_ns != &init_user_ns)
return ERR_PTR(-EPERM);
- return vfs_kern_mount(type, MS_SUBMOUNT, name, data);
+ return vfs_kern_mount(type, SB_SUBMOUNT, name, data);
}
EXPORT_SYMBOL_GPL(vfs_submount);
@@ -1123,12 +1184,10 @@ static LLIST_HEAD(delayed_mntput_list);
static void delayed_mntput(struct work_struct *unused)
{
struct llist_node *node = llist_del_all(&delayed_mntput_list);
- struct llist_node *next;
+ struct mount *m, *t;
- for (; node; node = next) {
- next = llist_next(node);
- cleanup_mnt(llist_entry(node, struct mount, mnt_llist));
- }
+ llist_for_each_entry_safe(m, t, node, mnt_llist)
+ cleanup_mnt(m);
}
static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput);
@@ -1237,65 +1296,6 @@ struct vfsmount *mnt_clone_internal(const struct path *path)
return &p->mnt;
}
-static inline void mangle(struct seq_file *m, const char *s)
-{
- seq_escape(m, s, " \t\n\\");
-}
-
-/*
- * Simple .show_options callback for filesystems which don't want to
- * implement more complex mount option showing.
- *
- * See also save_mount_options().
- */
-int generic_show_options(struct seq_file *m, struct dentry *root)
-{
- const char *options;
-
- rcu_read_lock();
- options = rcu_dereference(root->d_sb->s_options);
-
- if (options != NULL && options[0]) {
- seq_putc(m, ',');
- mangle(m, options);
- }
- rcu_read_unlock();
-
- return 0;
-}
-EXPORT_SYMBOL(generic_show_options);
-
-/*
- * If filesystem uses generic_show_options(), this function should be
- * called from the fill_super() callback.
- *
- * The .remount_fs callback usually needs to be handled in a special
- * way, to make sure, that previous options are not overwritten if the
- * remount fails.
- *
- * Also note, that if the filesystem's .remount_fs function doesn't
- * reset all options to their default value, but changes only newly
- * given options, then the displayed options will not reflect reality
- * any more.
- */
-void save_mount_options(struct super_block *sb, char *options)
-{
- BUG_ON(sb->s_options);
- rcu_assign_pointer(sb->s_options, kstrdup(options, GFP_KERNEL));
-}
-EXPORT_SYMBOL(save_mount_options);
-
-void replace_mount_options(struct super_block *sb, char *options)
-{
- char *old = sb->s_options;
- rcu_assign_pointer(sb->s_options, options);
- if (old) {
- synchronize_rcu();
- kfree(old);
- }
-}
-EXPORT_SYMBOL(replace_mount_options);
-
#ifdef CONFIG_PROC_FS
/* iterator; we want it to have access to namespace_sem, thus here... */
static void *m_start(struct seq_file *m, loff_t *pos)
@@ -1592,8 +1592,8 @@ static int do_umount(struct mount *mnt, int flags)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
down_write(&sb->s_umount);
- if (!(sb->s_flags & MS_RDONLY))
- retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
+ if (!sb_rdonly(sb))
+ retval = do_remount_sb(sb, SB_RDONLY, NULL, 0);
up_write(&sb->s_umount);
return retval;
}
@@ -1656,7 +1656,7 @@ out_unlock:
namespace_unlock();
}
-/*
+/*
* Is the caller allowed to modify his namespace?
*/
static inline bool may_mount(void)
@@ -2117,7 +2117,7 @@ static void unlock_mount(struct mountpoint *where)
static int graft_tree(struct mount *mnt, struct mount *p, struct mountpoint *mp)
{
- if (mnt->mnt.mnt_sb->s_flags & MS_NOUSER)
+ if (mnt->mnt.mnt_sb->s_flags & SB_NOUSER)
return -EINVAL;
if (d_is_dir(mp->m_dentry) !=
@@ -2131,9 +2131,9 @@ static int graft_tree(struct mount *mnt, struct mount *p, struct mountpoint *mp)
* Sanity check the flags to change_mnt_propagation.
*/
-static int flags_to_propagation_type(int flags)
+static int flags_to_propagation_type(int ms_flags)
{
- int type = flags & ~(MS_REC | MS_SILENT);
+ int type = ms_flags & ~(MS_REC | MS_SILENT);
/* Fail if any non-propagation flags are set */
if (type & ~(MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
@@ -2147,18 +2147,18 @@ static int flags_to_propagation_type(int flags)
/*
* recursively change the type of the mountpoint.
*/
-static int do_change_type(struct path *path, int flag)
+static int do_change_type(struct path *path, int ms_flags)
{
struct mount *m;
struct mount *mnt = real_mount(path->mnt);
- int recurse = flag & MS_REC;
+ int recurse = ms_flags & MS_REC;
int type;
int err = 0;
if (path->dentry != path->mnt->mnt_root)
return -EINVAL;
- type = flags_to_propagation_type(flag);
+ type = flags_to_propagation_type(ms_flags);
if (!type)
return -EINVAL;
@@ -2210,7 +2210,7 @@ static int do_loopback(struct path *path, const char *old_name,
err = -EINVAL;
if (mnt_ns_loop(old_path.dentry))
- goto out;
+ goto out;
mp = lock_mount(path);
err = PTR_ERR(mp);
@@ -2280,8 +2280,8 @@ static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
* If you've mounted a non-root directory somewhere and want to do remount
* on it - tough luck.
*/
-static int do_remount(struct path *path, int flags, int mnt_flags,
- void *data)
+static int do_remount(struct path *path, int ms_flags, int sb_flags,
+ int mnt_flags, void *data)
{
int err;
struct super_block *sb = path->mnt->mnt_sb;
@@ -2325,12 +2325,12 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
return err;
down_write(&sb->s_umount);
- if (flags & MS_BIND)
- err = change_mount_flags(path->mnt, flags);
+ if (ms_flags & MS_BIND)
+ err = change_mount_flags(path->mnt, ms_flags);
else if (!capable(CAP_SYS_ADMIN))
err = -EPERM;
else
- err = do_remount_sb(sb, flags, data, 0);
+ err = do_remount_sb(sb, sb_flags, data, 0);
if (!err) {
lock_mount_hash();
mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
@@ -2495,7 +2495,7 @@ static bool mount_too_revealing(struct vfsmount *mnt, int *new_mnt_flags);
* create a new mount for userspace and request it to be added into the
* namespace's tree
*/
-static int do_new_mount(struct path *path, const char *fstype, int flags,
+static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
int mnt_flags, const char *name, void *data)
{
struct file_system_type *type;
@@ -2509,7 +2509,7 @@ static int do_new_mount(struct path *path, const char *fstype, int flags,
if (!type)
return -ENODEV;
- mnt = vfs_kern_mount(type, flags, name, data);
+ mnt = vfs_kern_mount(type, sb_flags, name, data);
if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
!mnt->mnt_sb->s_subtype)
mnt = fs_set_subtype(mnt, fstype);
@@ -2764,8 +2764,8 @@ long do_mount(const char *dev_name, const char __user *dir_name,
const char *type_page, unsigned long flags, void *data_page)
{
struct path path;
+ unsigned int mnt_flags = 0, sb_flags;
int retval = 0;
- int mnt_flags = 0;
/* Discard magic */
if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
@@ -2775,6 +2775,9 @@ long do_mount(const char *dev_name, const char __user *dir_name,
if (data_page)
((char *)data_page)[PAGE_SIZE - 1] = 0;
+ if (flags & MS_NOUSER)
+ return -EINVAL;
+
/* ... and get the mountpoint */
retval = user_path(dir_name, &path);
if (retval)
@@ -2784,7 +2787,7 @@ long do_mount(const char *dev_name, const char __user *dir_name,
type_page, flags, data_page);
if (!retval && !may_mount())
retval = -EPERM;
- if (!retval && (flags & MS_MANDLOCK) && !may_mandlock())
+ if (!retval && (flags & SB_MANDLOCK) && !may_mandlock())
retval = -EPERM;
if (retval)
goto dput_out;
@@ -2806,7 +2809,7 @@ long do_mount(const char *dev_name, const char __user *dir_name,
mnt_flags |= MNT_NODIRATIME;
if (flags & MS_STRICTATIME)
mnt_flags &= ~(MNT_RELATIME | MNT_NOATIME);
- if (flags & MS_RDONLY)
+ if (flags & SB_RDONLY)
mnt_flags |= MNT_READONLY;
/* The default atime for remount is preservation */
@@ -2817,12 +2820,16 @@ long do_mount(const char *dev_name, const char __user *dir_name,
mnt_flags |= path.mnt->mnt_flags & MNT_ATIME_MASK;
}
- flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | MS_BORN |
- MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
- MS_STRICTATIME | MS_NOREMOTELOCK | MS_SUBMOUNT);
+ sb_flags = flags & (SB_RDONLY |
+ SB_SYNCHRONOUS |
+ SB_MANDLOCK |
+ SB_DIRSYNC |
+ SB_SILENT |
+ SB_POSIXACL |
+ SB_I_VERSION);
if (flags & MS_REMOUNT)
- retval = do_remount(&path, flags & ~MS_REMOUNT, mnt_flags,
+ retval = do_remount(&path, flags, sb_flags, mnt_flags,
data_page);
else if (flags & MS_BIND)
retval = do_loopback(&path, dev_name, flags & MS_REC);
@@ -2831,7 +2838,7 @@ long do_mount(const char *dev_name, const char __user *dir_name,
else if (flags & MS_MOVE)
retval = do_move_mount(&path, dev_name);
else
- retval = do_new_mount(&path, type_page, flags, mnt_flags,
+ retval = do_new_mount(&path, type_page, sb_flags, mnt_flags,
dev_name, data_page);
dput_out:
path_put(&path);
@@ -3238,7 +3245,6 @@ static void __init init_mount_tree(void)
void __init mnt_init(void)
{
- unsigned u;
int err;
mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount),
@@ -3247,22 +3253,17 @@ void __init mnt_init(void)
mount_hashtable = alloc_large_system_hash("Mount-cache",
sizeof(struct hlist_head),
mhash_entries, 19,
- 0,
+ HASH_ZERO,
&m_hash_shift, &m_hash_mask, 0, 0);
mountpoint_hashtable = alloc_large_system_hash("Mountpoint-cache",
sizeof(struct hlist_head),
mphash_entries, 19,
- 0,
+ HASH_ZERO,
&mp_hash_shift, &mp_hash_mask, 0, 0);
if (!mount_hashtable || !mountpoint_hashtable)
panic("Failed to allocate mount hash table\n");
- for (u = 0; u <= m_hash_mask; u++)
- INIT_HLIST_HEAD(&mount_hashtable[u]);
- for (u = 0; u <= mp_hash_mask; u++)
- INIT_HLIST_HEAD(&mountpoint_hashtable[u]);
-
kernfs_init();
err = sysfs_init();
@@ -3287,7 +3288,7 @@ void put_mnt_ns(struct mnt_namespace *ns)
struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
{
struct vfsmount *mnt;
- mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
+ mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, data);
if (!IS_ERR(mnt)) {
/*
* it is a longterm mount, don't release mnt until
@@ -3364,7 +3365,7 @@ static bool mnt_already_visible(struct mnt_namespace *ns, struct vfsmount *new,
mnt_flags = mnt->mnt.mnt_flags;
/* Don't miss readonly hidden in the superblock flags */
- if (mnt->mnt.mnt_sb->s_flags & MS_RDONLY)
+ if (sb_rdonly(mnt->mnt.mnt_sb))
mnt_flags |= MNT_LOCK_READONLY;
/* Verify the mount flags are equal to or more permissive
generated by cgit v1.2.3 (git 2.46.0) at 2025-09-06 15:41:16 +0000