diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/namespace.c | 42 | ||||
| -rw-r--r-- | fs/overlayfs/export.c | 2 | ||||
| -rw-r--r-- | fs/overlayfs/file.c | 47 | ||||
| -rw-r--r-- | fs/overlayfs/readdir.c | 5 |
4 files changed, 80 insertions, 16 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index ab4174a3c802..f79d9471cb76 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1938,6 +1938,20 @@ void drop_collected_mounts(struct vfsmount *mnt) namespace_unlock(); } +static bool has_locked_children(struct mount *mnt, struct dentry *dentry) +{ + struct mount *child; + + list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) { + if (!is_subdir(child->mnt_mountpoint, dentry)) + continue; + + if (child->mnt.mnt_flags & MNT_LOCKED) + return true; + } + return false; +} + /** * clone_private_mount - create a private clone of a path * @path: path to clone @@ -1953,10 +1967,19 @@ struct vfsmount *clone_private_mount(const struct path *path) struct mount *old_mnt = real_mount(path->mnt); struct mount *new_mnt; + down_read(&namespace_sem); if (IS_MNT_UNBINDABLE(old_mnt)) - return ERR_PTR(-EINVAL); + goto invalid; + + if (!check_mnt(old_mnt)) + goto invalid; + + if (has_locked_children(old_mnt, path->dentry)) + goto invalid; new_mnt = clone_mnt(old_mnt, path->dentry, CL_PRIVATE); + up_read(&namespace_sem); + if (IS_ERR(new_mnt)) return ERR_CAST(new_mnt); @@ -1964,6 +1987,10 @@ struct vfsmount *clone_private_mount(const struct path *path) new_mnt->mnt_ns = MNT_NS_INTERNAL; return &new_mnt->mnt; + +invalid: + up_read(&namespace_sem); + return ERR_PTR(-EINVAL); } EXPORT_SYMBOL_GPL(clone_private_mount); @@ -2315,19 +2342,6 @@ static int do_change_type(struct path *path, int ms_flags) return err; } -static bool has_locked_children(struct mount *mnt, struct dentry *dentry) -{ - struct mount *child; - list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) { - if (!is_subdir(child->mnt_mountpoint, dentry)) - continue; - - if (child->mnt.mnt_flags & MNT_LOCKED) - return true; - } - return false; -} - static struct mount *__do_loopback(struct path *old_path, int recurse) { struct mount *mnt = ERR_PTR(-EINVAL), *old = real_mount(old_path->mnt); diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 41ebf52f1bbc..ebde05c9cf62 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -392,6 +392,7 @@ static struct dentry *ovl_lookup_real_one(struct dentry *connected, */ take_dentry_name_snapshot(&name, real); this = lookup_one_len(name.name.name, connected, name.name.len); + release_dentry_name_snapshot(&name); err = PTR_ERR(this); if (IS_ERR(this)) { goto fail; @@ -406,7 +407,6 @@ static struct dentry *ovl_lookup_real_one(struct dentry *connected, } out: - release_dentry_name_snapshot(&name); dput(parent); inode_unlock(dir); return this; diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 4d53d3b7e5fe..d081faa55e83 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -392,6 +392,51 @@ out_unlock: return ret; } +/* + * Calling iter_file_splice_write() directly from overlay's f_op may deadlock + * due to lock order inversion between pipe->mutex in iter_file_splice_write() + * and file_start_write(real.file) in ovl_write_iter(). + * + * So do everything ovl_write_iter() does and call iter_file_splice_write() on + * the real file. + */ +static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags) +{ + struct fd real; + const struct cred *old_cred; + struct inode *inode = file_inode(out); + struct inode *realinode = ovl_inode_real(inode); + ssize_t ret; + + inode_lock(inode); + /* Update mode */ + ovl_copyattr(realinode, inode); + ret = file_remove_privs(out); + if (ret) + goto out_unlock; + + ret = ovl_real_fdget(out, &real); + if (ret) + goto out_unlock; + + old_cred = ovl_override_creds(inode->i_sb); + file_start_write(real.file); + + ret = iter_file_splice_write(pipe, real.file, ppos, len, flags); + + file_end_write(real.file); + /* Update size */ + ovl_copyattr(realinode, inode); + revert_creds(old_cred); + fdput(real); + +out_unlock: + inode_unlock(inode); + + return ret; +} + static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct fd real; @@ -603,7 +648,7 @@ const struct file_operations ovl_file_operations = { .fadvise = ovl_fadvise, .flush = ovl_flush, .splice_read = generic_file_splice_read, - .splice_write = iter_file_splice_write, + .splice_write = ovl_splice_write, .copy_file_range = ovl_copy_file_range, .remap_file_range = ovl_remap_file_range, diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index e8ad2c2c77dd..150fdf3bc68d 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -481,6 +481,8 @@ static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p) } this = lookup_one_len(p->name, dir, p->len); if (IS_ERR_OR_NULL(this) || !this->d_inode) { + /* Mark a stale entry */ + p->is_whiteout = true; if (IS_ERR(this)) { err = PTR_ERR(this); this = NULL; @@ -776,6 +778,9 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) if (err) goto out; } + } + /* ovl_cache_update_ino() sets is_whiteout on stale entry */ + if (!p->is_whiteout) { if (!dir_emit(ctx, p->name, p->len, p->ino, p->type)) break; } |