blob: 13fa6f3df8e4651af389223e0e1b94994ea6b172 [file] [log] [blame]
Thomas Gleixnerb4d0d232019-05-20 19:08:01 +02001/* SPDX-License-Identifier: GPL-2.0-or-later */
David Howells9bc61ab2018-11-04 03:19:03 -05002/* Filesystem superblock creation and reconfiguration context.
3 *
4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells ([email protected])
David Howells9bc61ab2018-11-04 03:19:03 -05006 */
7
8#ifndef _LINUX_FS_CONTEXT_H
9#define _LINUX_FS_CONTEXT_H
10
11#include <linux/kernel.h>
David Howells007ec262018-11-01 23:34:29 +000012#include <linux/refcount.h>
David Howells9bc61ab2018-11-04 03:19:03 -050013#include <linux/errno.h>
14#include <linux/security.h>
David Howells24dcb3d2018-11-01 23:33:31 +000015#include <linux/mutex.h>
David Howells9bc61ab2018-11-04 03:19:03 -050016
17struct cred;
18struct dentry;
19struct file_operations;
20struct file_system_type;
Al Virof3a09c92018-12-23 18:55:56 -050021struct mnt_namespace;
David Howells9bc61ab2018-11-04 03:19:03 -050022struct net;
Al Virof3a09c92018-12-23 18:55:56 -050023struct pid_namespace;
24struct super_block;
David Howells9bc61ab2018-11-04 03:19:03 -050025struct user_namespace;
Al Virof3a09c92018-12-23 18:55:56 -050026struct vfsmount;
27struct path;
David Howells9bc61ab2018-11-04 03:19:03 -050028
29enum fs_context_purpose {
30 FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */
Al Viroe1a91582018-12-23 16:25:31 -050031 FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */
David Howells8d0347f2018-11-04 09:28:36 -050032 FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */
David Howells9bc61ab2018-11-04 03:19:03 -050033};
34
35/*
David Howells24dcb3d2018-11-01 23:33:31 +000036 * Userspace usage phase for fsopen/fspick.
37 */
38enum fs_context_phase {
39 FS_CONTEXT_CREATE_PARAMS, /* Loading params for sb creation */
40 FS_CONTEXT_CREATING, /* A superblock is being created */
41 FS_CONTEXT_AWAITING_MOUNT, /* Superblock created, awaiting fsmount() */
42 FS_CONTEXT_AWAITING_RECONF, /* Awaiting initialisation for reconfiguration */
43 FS_CONTEXT_RECONF_PARAMS, /* Loading params for reconfiguration */
44 FS_CONTEXT_RECONFIGURING, /* Reconfiguring the superblock */
45 FS_CONTEXT_FAILED, /* Failed to correctly transition a context */
46};
47
48/*
David Howells31d921c2018-11-01 23:07:24 +000049 * Type of parameter value.
50 */
51enum fs_value_type {
52 fs_value_is_undefined,
53 fs_value_is_flag, /* Value not given a value */
54 fs_value_is_string, /* Value is a string */
55 fs_value_is_blob, /* Value is a binary blob */
56 fs_value_is_filename, /* Value is a filename* + dirfd */
David Howells31d921c2018-11-01 23:07:24 +000057 fs_value_is_file, /* Value is a file* */
58};
59
60/*
61 * Configuration parameter.
62 */
63struct fs_parameter {
64 const char *key; /* Parameter name */
65 enum fs_value_type type:8; /* The type of value here */
66 union {
67 char *string;
68 void *blob;
69 struct filename *name;
70 struct file *file;
71 };
72 size_t size;
73 int dirfd;
74};
75
Al Viro3fbb8d52019-12-20 23:43:32 -050076struct p_log {
77 const char *prefix;
78 struct fc_log *log;
79};
80
David Howells31d921c2018-11-01 23:07:24 +000081/*
David Howells9bc61ab2018-11-04 03:19:03 -050082 * Filesystem context for holding the parameters used in the creation or
83 * reconfiguration of a superblock.
84 *
85 * Superblock creation fills in ->root whereas reconfiguration begins with this
86 * already set.
87 *
Mauro Carvalho Chehab791a17e2020-04-27 23:17:09 +020088 * See Documentation/filesystems/mount_api.rst
David Howells9bc61ab2018-11-04 03:19:03 -050089 */
90struct fs_context {
Al Virof3a09c92018-12-23 18:55:56 -050091 const struct fs_context_operations *ops;
David Howells24dcb3d2018-11-01 23:33:31 +000092 struct mutex uapi_mutex; /* Userspace access mutex */
David Howells9bc61ab2018-11-04 03:19:03 -050093 struct file_system_type *fs_type;
94 void *fs_private; /* The filesystem's context */
David Howellsfe62c3a2019-03-27 14:15:16 +000095 void *sget_key;
David Howells9bc61ab2018-11-04 03:19:03 -050096 struct dentry *root; /* The root and superblock */
97 struct user_namespace *user_ns; /* The user namespace for this mount */
98 struct net *net_ns; /* The network namespace for this mount */
99 const struct cred *cred; /* The mounter's credentials */
Al Virocc3c0b52019-12-21 00:16:49 -0500100 struct p_log log; /* Logging buffer */
David Howells9bc61ab2018-11-04 03:19:03 -0500101 const char *source; /* The source name (eg. dev path) */
David Howells9bc61ab2018-11-04 03:19:03 -0500102 void *security; /* Linux S&M options */
Al Virocb50b3482018-12-23 17:25:47 -0500103 void *s_fs_info; /* Proposed s_fs_info */
David Howells9bc61ab2018-11-04 03:19:03 -0500104 unsigned int sb_flags; /* Proposed superblock flags (SB_*) */
105 unsigned int sb_flags_mask; /* Superblock flags that were changed */
David Howellsc80fa7c2019-03-25 16:38:23 +0000106 unsigned int s_iflags; /* OR'd with sb->s_iflags */
David Howells846e5662018-11-01 23:07:24 +0000107 unsigned int lsm_flags; /* Information flags from the fs to the LSM */
David Howells9bc61ab2018-11-04 03:19:03 -0500108 enum fs_context_purpose purpose:8;
David Howells24dcb3d2018-11-01 23:33:31 +0000109 enum fs_context_phase phase:8; /* The phase the context is in */
David Howells9bc61ab2018-11-04 03:19:03 -0500110 bool need_free:1; /* Need to call ops->free() */
Al Virocb50b3482018-12-23 17:25:47 -0500111 bool global:1; /* Goes into &init_user_ns */
Miklos Szeredib3309662020-07-14 14:45:41 +0200112 bool oldapi:1; /* Coming from mount(2) */
David Howells9bc61ab2018-11-04 03:19:03 -0500113};
114
Al Virof3a09c92018-12-23 18:55:56 -0500115struct fs_context_operations {
116 void (*free)(struct fs_context *fc);
Al Viro0b520752018-12-23 16:02:47 -0500117 int (*dup)(struct fs_context *fc, struct fs_context *src_fc);
David Howells3e1aeb02018-11-01 23:07:25 +0000118 int (*parse_param)(struct fs_context *fc, struct fs_parameter *param);
Al Virof3a09c92018-12-23 18:55:56 -0500119 int (*parse_monolithic)(struct fs_context *fc, void *data);
120 int (*get_tree)(struct fs_context *fc);
121 int (*reconfigure)(struct fs_context *fc);
122};
123
David Howells9bc61ab2018-11-04 03:19:03 -0500124/*
125 * fs_context manipulation functions.
126 */
127extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type,
128 unsigned int sb_flags);
David Howells8d0347f2018-11-04 09:28:36 -0500129extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
130 unsigned int sb_flags,
131 unsigned int sb_flags_mask);
Al Viroe1a91582018-12-23 16:25:31 -0500132extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type,
133 struct dentry *reference);
David Howells9bc61ab2018-11-04 03:19:03 -0500134
Al Viro0b520752018-12-23 16:02:47 -0500135extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc);
David Howells3e1aeb02018-11-01 23:07:25 +0000136extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
137extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
138 const char *value, size_t v_size);
139extern int generic_parse_monolithic(struct fs_context *fc, void *data);
David Howells9bc61ab2018-11-04 03:19:03 -0500140extern int vfs_get_tree(struct fs_context *fc);
141extern void put_fs_context(struct fs_context *fc);
Christian Braunerd1d488d2021-07-14 15:47:50 +0200142extern int vfs_parse_fs_param_source(struct fs_context *fc,
143 struct fs_parameter *param);
Paul Gortmaker1e7107c2021-06-16 08:51:57 -0400144extern void fc_drop_locked(struct fs_context *fc);
NeilBrowna6097182022-01-17 09:07:26 +1100145int reconfigure_single(struct super_block *s,
146 int flags, void *data);
David Howells9bc61ab2018-11-04 03:19:03 -0500147
Al Virocb50b3482018-12-23 17:25:47 -0500148/*
Al Viro533770c2019-09-03 19:05:48 -0400149 * sget() wrappers to be called from the ->get_tree() op.
Al Virocb50b3482018-12-23 17:25:47 -0500150 */
151enum vfs_get_super_keying {
152 vfs_get_single_super, /* Only one such superblock may exist */
David Howells43ce4c1f2019-03-21 09:22:36 +0000153 vfs_get_single_reconf_super, /* As above, but reconfigure if it exists */
Al Virocb50b3482018-12-23 17:25:47 -0500154 vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */
155 vfs_get_independent_super, /* Multiple independent superblocks may exist */
156};
157extern int vfs_get_super(struct fs_context *fc,
158 enum vfs_get_super_keying keying,
159 int (*fill_super)(struct super_block *sb,
160 struct fs_context *fc));
Al Viro533770c2019-09-03 19:05:48 -0400161
Al Viro2ac295d2019-06-01 20:48:55 -0400162extern int get_tree_nodev(struct fs_context *fc,
163 int (*fill_super)(struct super_block *sb,
164 struct fs_context *fc));
Al Viroc23a0bb2019-05-22 21:23:39 -0400165extern int get_tree_single(struct fs_context *fc,
166 int (*fill_super)(struct super_block *sb,
167 struct fs_context *fc));
David Howells43ce4c1f2019-03-21 09:22:36 +0000168extern int get_tree_single_reconf(struct fs_context *fc,
169 int (*fill_super)(struct super_block *sb,
170 struct fs_context *fc));
Al Viro533770c2019-09-03 19:05:48 -0400171extern int get_tree_keyed(struct fs_context *fc,
172 int (*fill_super)(struct super_block *sb,
173 struct fs_context *fc),
174 void *key);
Al Virocb50b3482018-12-23 17:25:47 -0500175
David Howellsfe62c3a2019-03-27 14:15:16 +0000176extern int get_tree_bdev(struct fs_context *fc,
177 int (*fill_super)(struct super_block *sb,
178 struct fs_context *fc));
179
David Howellse7582e162018-11-01 23:07:26 +0000180extern const struct file_operations fscontext_fops;
181
David Howells007ec262018-11-01 23:34:29 +0000182/*
183 * Mount error, warning and informational message logging. This structure is
184 * shareable between a mount and a subordinate mount.
185 */
186struct fc_log {
187 refcount_t usage;
188 u8 head; /* Insertion index in buffer[] */
189 u8 tail; /* Removal index in buffer[] */
190 u8 need_free; /* Mask of kfree'able items in buffer[] */
191 struct module *owner; /* Owner module for strings that don't then need freeing */
192 char *buffer[8];
193};
194
Al Viro9f09f642019-12-20 22:10:36 -0500195extern __attribute__((format(printf, 4, 5)))
196void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...);
David Howellsc6b82262018-11-01 23:07:23 +0000197
Al Virocc3c0b52019-12-21 00:16:49 -0500198#define __logfc(fc, l, fmt, ...) logfc((fc)->log.log, NULL, \
Al Viro7f5d3812019-12-20 23:52:55 -0500199 l, fmt, ## __VA_ARGS__)
Al Viro3fbb8d52019-12-20 23:43:32 -0500200#define __plog(p, l, fmt, ...) logfc((p)->log, (p)->prefix, \
201 l, fmt, ## __VA_ARGS__)
David Howellsc6b82262018-11-01 23:07:23 +0000202/**
203 * infof - Store supplementary informational message
204 * @fc: The context in which to log the informational message
205 * @fmt: The format string
206 *
207 * Store the supplementary informational message for the process if the process
208 * has enabled the facility.
209 */
Al Viro9f09f642019-12-20 22:10:36 -0500210#define infof(fc, fmt, ...) __logfc(fc, 'i', fmt, ## __VA_ARGS__)
Al Viro3fbb8d52019-12-20 23:43:32 -0500211#define info_plog(p, fmt, ...) __plog(p, 'i', fmt, ## __VA_ARGS__)
Al Viroa3ff9372019-12-21 21:30:50 -0500212#define infofc(p, fmt, ...) __plog((&(fc)->log), 'i', fmt, ## __VA_ARGS__)
David Howellsc6b82262018-11-01 23:07:23 +0000213
214/**
215 * warnf - Store supplementary warning message
216 * @fc: The context in which to log the error message
217 * @fmt: The format string
218 *
219 * Store the supplementary warning message for the process if the process has
220 * enabled the facility.
221 */
Al Viro9f09f642019-12-20 22:10:36 -0500222#define warnf(fc, fmt, ...) __logfc(fc, 'w', fmt, ## __VA_ARGS__)
Al Viro3fbb8d52019-12-20 23:43:32 -0500223#define warn_plog(p, fmt, ...) __plog(p, 'w', fmt, ## __VA_ARGS__)
Al Viroa3ff9372019-12-21 21:30:50 -0500224#define warnfc(fc, fmt, ...) __plog((&(fc)->log), 'w', fmt, ## __VA_ARGS__)
David Howellsc6b82262018-11-01 23:07:23 +0000225
226/**
227 * errorf - Store supplementary error message
228 * @fc: The context in which to log the error message
229 * @fmt: The format string
230 *
231 * Store the supplementary error message for the process if the process has
232 * enabled the facility.
233 */
Al Viro9f09f642019-12-20 22:10:36 -0500234#define errorf(fc, fmt, ...) __logfc(fc, 'e', fmt, ## __VA_ARGS__)
Al Viro3fbb8d52019-12-20 23:43:32 -0500235#define error_plog(p, fmt, ...) __plog(p, 'e', fmt, ## __VA_ARGS__)
Al Viroa3ff9372019-12-21 21:30:50 -0500236#define errorfc(fc, fmt, ...) __plog((&(fc)->log), 'e', fmt, ## __VA_ARGS__)
David Howellsc6b82262018-11-01 23:07:23 +0000237
238/**
239 * invalf - Store supplementary invalid argument error message
240 * @fc: The context in which to log the error message
241 * @fmt: The format string
242 *
243 * Store the supplementary error message for the process if the process has
244 * enabled the facility and return -EINVAL.
245 */
Al Viro9f09f642019-12-20 22:10:36 -0500246#define invalf(fc, fmt, ...) (errorf(fc, fmt, ## __VA_ARGS__), -EINVAL)
Al Viro3fbb8d52019-12-20 23:43:32 -0500247#define inval_plog(p, fmt, ...) (error_plog(p, fmt, ## __VA_ARGS__), -EINVAL)
Al Viroa3ff9372019-12-21 21:30:50 -0500248#define invalfc(fc, fmt, ...) (errorfc(fc, fmt, ## __VA_ARGS__), -EINVAL)
David Howellsc6b82262018-11-01 23:07:23 +0000249
David Howells9bc61ab2018-11-04 03:19:03 -0500250#endif /* _LINUX_FS_CONTEXT_H */