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_filename_empty
, /* Value is a filename* + dirfd + AT_EMPTY_PATH */
58 fs_value_is_file
, /* Value is a file* */
62 * Configuration parameter.
65 const char *key
; /* Parameter name */
66 enum fs_value_type type
:8; /* The type of value here */
70 struct filename
*name
;
78 * Filesystem context for holding the parameters used in the creation or
79 * reconfiguration of a superblock.
81 * Superblock creation fills in ->root whereas reconfiguration begins with this
84 * See Documentation/filesystems/mounting.txt
87 const struct fs_context_operations
*ops
;
88 struct mutex uapi_mutex
; /* Userspace access mutex */
89 struct file_system_type
*fs_type
;
90 void *fs_private
; /* The filesystem's context */
91 struct dentry
*root
; /* The root and superblock */
92 struct user_namespace
*user_ns
; /* The user namespace for this mount */
93 struct net
*net_ns
; /* The network namespace for this mount */
94 const struct cred
*cred
; /* The mounter's credentials */
95 struct fc_log
*log
; /* Logging buffer */
96 const char *source
; /* The source name (eg. dev path) */
97 const char *subtype
; /* The subtype to set on the superblock */
98 void *security
; /* Linux S&M options */
99 void *s_fs_info
; /* Proposed s_fs_info */
100 unsigned int sb_flags
; /* Proposed superblock flags (SB_*) */
101 unsigned int sb_flags_mask
; /* Superblock flags that were changed */
102 unsigned int lsm_flags
; /* Information flags from the fs to the LSM */
103 enum fs_context_purpose purpose
:8;
104 enum fs_context_phase phase
:8; /* The phase the context is in */
105 bool need_free
:1; /* Need to call ops->free() */
106 bool global
:1; /* Goes into &init_user_ns */
109 struct fs_context_operations
{
110 void (*free
)(struct fs_context
*fc
);
111 int (*dup
)(struct fs_context
*fc
, struct fs_context
*src_fc
);
112 int (*parse_param
)(struct fs_context
*fc
, struct fs_parameter
*param
);
113 int (*parse_monolithic
)(struct fs_context
*fc
, void *data
);
114 int (*get_tree
)(struct fs_context
*fc
);
115 int (*reconfigure
)(struct fs_context
*fc
);
119 * fs_context manipulation functions.
121 extern struct fs_context
*fs_context_for_mount(struct file_system_type
*fs_type
,
122 unsigned int sb_flags
);
123 extern struct fs_context
*fs_context_for_reconfigure(struct dentry
*dentry
,
124 unsigned int sb_flags
,
125 unsigned int sb_flags_mask
);
126 extern struct fs_context
*fs_context_for_submount(struct file_system_type
*fs_type
,
127 struct dentry
*reference
);
129 extern struct fs_context
*vfs_dup_fs_context(struct fs_context
*fc
);
130 extern int vfs_parse_fs_param(struct fs_context
*fc
, struct fs_parameter
*param
);
131 extern int vfs_parse_fs_string(struct fs_context
*fc
, const char *key
,
132 const char *value
, size_t v_size
);
133 extern int generic_parse_monolithic(struct fs_context
*fc
, void *data
);
134 extern int vfs_get_tree(struct fs_context
*fc
);
135 extern void put_fs_context(struct fs_context
*fc
);
138 * sget() wrapper to be called from the ->get_tree() op.
140 enum vfs_get_super_keying
{
141 vfs_get_single_super
, /* Only one such superblock may exist */
142 vfs_get_keyed_super
, /* Superblocks with different s_fs_info keys may exist */
143 vfs_get_independent_super
, /* Multiple independent superblocks may exist */
145 extern int vfs_get_super(struct fs_context
*fc
,
146 enum vfs_get_super_keying keying
,
147 int (*fill_super
)(struct super_block
*sb
,
148 struct fs_context
*fc
));
150 extern const struct file_operations fscontext_fops
;
153 * Mount error, warning and informational message logging. This structure is
154 * shareable between a mount and a subordinate mount.
158 u8 head
; /* Insertion index in buffer[] */
159 u8 tail
; /* Removal index in buffer[] */
160 u8 need_free
; /* Mask of kfree'able items in buffer[] */
161 struct module
*owner
; /* Owner module for strings that don't then need freeing */
165 extern __attribute__((format(printf
, 2, 3)))
166 void logfc(struct fs_context
*fc
, const char *fmt
, ...);
169 * infof - Store supplementary informational message
170 * @fc: The context in which to log the informational message
171 * @fmt: The format string
173 * Store the supplementary informational message for the process if the process
174 * has enabled the facility.
176 #define infof(fc, fmt, ...) ({ logfc(fc, "i "fmt, ## __VA_ARGS__); })
179 * warnf - Store supplementary warning message
180 * @fc: The context in which to log the error message
181 * @fmt: The format string
183 * Store the supplementary warning message for the process if the process has
184 * enabled the facility.
186 #define warnf(fc, fmt, ...) ({ logfc(fc, "w "fmt, ## __VA_ARGS__); })
189 * errorf - Store supplementary error message
190 * @fc: The context in which to log the error message
191 * @fmt: The format string
193 * Store the supplementary error message for the process if the process has
194 * enabled the facility.
196 #define errorf(fc, fmt, ...) ({ logfc(fc, "e "fmt, ## __VA_ARGS__); })
199 * invalf - Store supplementary invalid argument error message
200 * @fc: The context in which to log the error message
201 * @fmt: The format string
203 * Store the supplementary error message for the process if the process has
204 * enabled the facility and return -EINVAL.
206 #define invalf(fc, fmt, ...) ({ errorf(fc, fmt, ## __VA_ARGS__); -EINVAL; })
208 #endif /* _LINUX_FS_CONTEXT_H */