1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* Filesystem superblock creation and reconfiguration context.
4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
8 #ifndef _LINUX_FS_CONTEXT_H
9 #define _LINUX_FS_CONTEXT_H
11 #include <linux/kernel.h>
12 #include <linux/refcount.h>
13 #include <linux/errno.h>
14 #include <linux/security.h>
15 #include <linux/mutex.h>
19 struct file_operations
;
20 struct file_system_type
;
25 struct user_namespace
;
29 enum fs_context_purpose
{
30 FS_CONTEXT_FOR_MOUNT
, /* New superblock for explicit mount */
31 FS_CONTEXT_FOR_SUBMOUNT
, /* New superblock for automatic submount */
32 FS_CONTEXT_FOR_RECONFIGURE
, /* Superblock reconfiguration (remount) */
36 * Userspace usage phase for fsopen/fspick.
38 enum 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 */
49 * Type of parameter value.
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 */
57 fs_value_is_file
, /* Value is a file* */
61 * Configuration parameter.
64 const char *key
; /* Parameter name */
65 enum fs_value_type type
:8; /* The type of value here */
69 struct filename
*name
;
82 * Filesystem context for holding the parameters used in the creation or
83 * reconfiguration of a superblock.
85 * Superblock creation fills in ->root whereas reconfiguration begins with this
88 * See Documentation/filesystems/mount_api.rst
91 const struct fs_context_operations
*ops
;
92 struct mutex uapi_mutex
; /* Userspace access mutex */
93 struct file_system_type
*fs_type
;
94 void *fs_private
; /* The filesystem's context */
96 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 */
100 struct p_log log
; /* Logging buffer */
101 const char *source
; /* The source name (eg. dev path) */
102 void *security
; /* Linux S&M options */
103 void *s_fs_info
; /* Proposed s_fs_info */
104 unsigned int sb_flags
; /* Proposed superblock flags (SB_*) */
105 unsigned int sb_flags_mask
; /* Superblock flags that were changed */
106 unsigned int s_iflags
; /* OR'd with sb->s_iflags */
107 unsigned int lsm_flags
; /* Information flags from the fs to the LSM */
108 enum fs_context_purpose purpose
:8;
109 enum fs_context_phase phase
:8; /* The phase the context is in */
110 bool need_free
:1; /* Need to call ops->free() */
111 bool global
:1; /* Goes into &init_user_ns */
112 bool oldapi
:1; /* Coming from mount(2) */
115 struct fs_context_operations
{
116 void (*free
)(struct fs_context
*fc
);
117 int (*dup
)(struct fs_context
*fc
, struct fs_context
*src_fc
);
118 int (*parse_param
)(struct fs_context
*fc
, struct fs_parameter
*param
);
119 int (*parse_monolithic
)(struct fs_context
*fc
, void *data
);
120 int (*get_tree
)(struct fs_context
*fc
);
121 int (*reconfigure
)(struct fs_context
*fc
);
125 * fs_context manipulation functions.
127 extern struct fs_context
*fs_context_for_mount(struct file_system_type
*fs_type
,
128 unsigned int sb_flags
);
129 extern struct fs_context
*fs_context_for_reconfigure(struct dentry
*dentry
,
130 unsigned int sb_flags
,
131 unsigned int sb_flags_mask
);
132 extern struct fs_context
*fs_context_for_submount(struct file_system_type
*fs_type
,
133 struct dentry
*reference
);
135 extern struct fs_context
*vfs_dup_fs_context(struct fs_context
*fc
);
136 extern int vfs_parse_fs_param(struct fs_context
*fc
, struct fs_parameter
*param
);
137 extern int vfs_parse_fs_string(struct fs_context
*fc
, const char *key
,
138 const char *value
, size_t v_size
);
139 extern int generic_parse_monolithic(struct fs_context
*fc
, void *data
);
140 extern int vfs_get_tree(struct fs_context
*fc
);
141 extern void put_fs_context(struct fs_context
*fc
);
144 * sget() wrappers to be called from the ->get_tree() op.
146 enum vfs_get_super_keying
{
147 vfs_get_single_super
, /* Only one such superblock may exist */
148 vfs_get_single_reconf_super
, /* As above, but reconfigure if it exists */
149 vfs_get_keyed_super
, /* Superblocks with different s_fs_info keys may exist */
150 vfs_get_independent_super
, /* Multiple independent superblocks may exist */
152 extern int vfs_get_super(struct fs_context
*fc
,
153 enum vfs_get_super_keying keying
,
154 int (*fill_super
)(struct super_block
*sb
,
155 struct fs_context
*fc
));
157 extern int get_tree_nodev(struct fs_context
*fc
,
158 int (*fill_super
)(struct super_block
*sb
,
159 struct fs_context
*fc
));
160 extern int get_tree_single(struct fs_context
*fc
,
161 int (*fill_super
)(struct super_block
*sb
,
162 struct fs_context
*fc
));
163 extern int get_tree_single_reconf(struct fs_context
*fc
,
164 int (*fill_super
)(struct super_block
*sb
,
165 struct fs_context
*fc
));
166 extern int get_tree_keyed(struct fs_context
*fc
,
167 int (*fill_super
)(struct super_block
*sb
,
168 struct fs_context
*fc
),
171 extern int get_tree_bdev(struct fs_context
*fc
,
172 int (*fill_super
)(struct super_block
*sb
,
173 struct fs_context
*fc
));
175 extern const struct file_operations fscontext_fops
;
178 * Mount error, warning and informational message logging. This structure is
179 * shareable between a mount and a subordinate mount.
183 u8 head
; /* Insertion index in buffer[] */
184 u8 tail
; /* Removal index in buffer[] */
185 u8 need_free
; /* Mask of kfree'able items in buffer[] */
186 struct module
*owner
; /* Owner module for strings that don't then need freeing */
190 extern __attribute__((format(printf
, 4, 5)))
191 void logfc(struct fc_log
*log
, const char *prefix
, char level
, const char *fmt
, ...);
193 #define __logfc(fc, l, fmt, ...) logfc((fc)->log.log, NULL, \
194 l, fmt, ## __VA_ARGS__)
195 #define __plog(p, l, fmt, ...) logfc((p)->log, (p)->prefix, \
196 l, fmt, ## __VA_ARGS__)
198 * infof - Store supplementary informational message
199 * @fc: The context in which to log the informational message
200 * @fmt: The format string
202 * Store the supplementary informational message for the process if the process
203 * has enabled the facility.
205 #define infof(fc, fmt, ...) __logfc(fc, 'i', fmt, ## __VA_ARGS__)
206 #define info_plog(p, fmt, ...) __plog(p, 'i', fmt, ## __VA_ARGS__)
207 #define infofc(p, fmt, ...) __plog((&(fc)->log), 'i', fmt, ## __VA_ARGS__)
210 * warnf - Store supplementary warning message
211 * @fc: The context in which to log the error message
212 * @fmt: The format string
214 * Store the supplementary warning message for the process if the process has
215 * enabled the facility.
217 #define warnf(fc, fmt, ...) __logfc(fc, 'w', fmt, ## __VA_ARGS__)
218 #define warn_plog(p, fmt, ...) __plog(p, 'w', fmt, ## __VA_ARGS__)
219 #define warnfc(fc, fmt, ...) __plog((&(fc)->log), 'w', fmt, ## __VA_ARGS__)
222 * errorf - Store supplementary error message
223 * @fc: The context in which to log the error message
224 * @fmt: The format string
226 * Store the supplementary error message for the process if the process has
227 * enabled the facility.
229 #define errorf(fc, fmt, ...) __logfc(fc, 'e', fmt, ## __VA_ARGS__)
230 #define error_plog(p, fmt, ...) __plog(p, 'e', fmt, ## __VA_ARGS__)
231 #define errorfc(fc, fmt, ...) __plog((&(fc)->log), 'e', fmt, ## __VA_ARGS__)
234 * invalf - Store supplementary invalid argument error message
235 * @fc: The context in which to log the error message
236 * @fmt: The format string
238 * Store the supplementary error message for the process if the process has
239 * enabled the facility and return -EINVAL.
241 #define invalf(fc, fmt, ...) (errorf(fc, fmt, ## __VA_ARGS__), -EINVAL)
242 #define inval_plog(p, fmt, ...) (error_plog(p, fmt, ## __VA_ARGS__), -EINVAL)
243 #define invalfc(fc, fmt, ...) (errorfc(fc, fmt, ## __VA_ARGS__), -EINVAL)
245 #endif /* _LINUX_FS_CONTEXT_H */