diff options
| -rw-r--r-- | fs/overlayfs/super.c | 125 |
1 files changed, 73 insertions, 52 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index a17702833dd0..592370ff453a 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -669,24 +669,6 @@ 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; @@ -706,6 +688,71 @@ 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; + + 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(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) { @@ -726,7 +773,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) struct dentry *root_dentry; struct ovl_entry *oe; struct ovl_fs *ufs; - struct kstatfs statfs; struct vfsmount *mnt; unsigned int i; int err; @@ -756,48 +802,23 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) if (err) goto out_put_upperpath; - err = ovl_mount_dir(ufs->config.lowerdir, &lowerpath); - if (err) - goto out_put_workpath; - - 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_lowerpath; - } - if (upperpath.mnt != workpath.mnt) { pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); - goto out_put_lowerpath; + 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_lowerpath; - } - - if (!ovl_is_allowed_fs_type(upperpath.dentry)) { - pr_err("overlayfs: filesystem of upperdir is not supported\n"); - goto out_put_lowerpath; - } - - if (!ovl_is_allowed_fs_type(lowerpath.dentry)) { - pr_err("overlayfs: filesystem of lowerdir is not supported\n"); - goto out_put_lowerpath; - } - - err = vfs_statfs(&lowerpath, &statfs); - if (err) { - pr_err("overlayfs: statfs failed on lowerpath\n"); - goto out_put_lowerpath; + goto out_put_workpath; } - ufs->lower_namelen = statfs.f_namelen; + sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth; - sb->s_stack_depth = max(upperpath.mnt->mnt_sb->s_stack_depth, - lowerpath.mnt->mnt_sb->s_stack_depth) + 1; + err = ovl_lower_dir(ufs->config.lowerdir, &lowerpath, + &ufs->lower_namelen, &sb->s_stack_depth); + if (err) + goto out_put_workpath; 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; |