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;
77 * Filesystem context for holding the parameters used in the creation or
78 * reconfiguration of a superblock.
80 * Superblock creation fills in ->root whereas reconfiguration begins with this
83 * See Documentation/filesystems/mount_api.txt
86 const struct fs_context_operations *ops;
87 struct mutex uapi_mutex; /* Userspace access mutex */
88 struct file_system_type *fs_type;
89 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 void *security; /* Linux S&M options */
98 void *s_fs_info; /* Proposed s_fs_info */
99 unsigned int sb_flags; /* Proposed superblock flags (SB_*) */
100 unsigned int sb_flags_mask; /* Superblock flags that were changed */
101 unsigned int s_iflags; /* OR'd with sb->s_iflags */
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() wrappers 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_single_reconf_super, /* As above, but reconfigure if it exists */
143 vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */
144 vfs_get_independent_super, /* Multiple independent superblocks may exist */
146 extern int vfs_get_super(struct fs_context *fc,
147 enum vfs_get_super_keying keying,
148 int (*fill_super)(struct super_block *sb,
149 struct fs_context *fc));
151 extern int get_tree_nodev(struct fs_context *fc,
152 int (*fill_super)(struct super_block *sb,
153 struct fs_context *fc));
154 extern int get_tree_single(struct fs_context *fc,
155 int (*fill_super)(struct super_block *sb,
156 struct fs_context *fc));
157 extern int get_tree_single_reconf(struct fs_context *fc,
158 int (*fill_super)(struct super_block *sb,
159 struct fs_context *fc));
160 extern int get_tree_keyed(struct fs_context *fc,
161 int (*fill_super)(struct super_block *sb,
162 struct fs_context *fc),
165 extern int get_tree_bdev(struct fs_context *fc,
166 int (*fill_super)(struct super_block *sb,
167 struct fs_context *fc));
169 extern const struct file_operations fscontext_fops;
172 * Mount error, warning and informational message logging. This structure is
173 * shareable between a mount and a subordinate mount.
177 u8 head; /* Insertion index in buffer[] */
178 u8 tail; /* Removal index in buffer[] */
179 u8 need_free; /* Mask of kfree'able items in buffer[] */
180 struct module *owner; /* Owner module for strings that don't then need freeing */
184 extern __attribute__((format(printf, 4, 5)))
185 void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...);
187 #define __logfc(fc, l, fmt, ...) ({ \
188 struct fs_context *__fc = (fc); \
189 logfc(__fc ? __fc->log : NULL, NULL, \
190 l, fmt, ## __VA_ARGS__);})
192 * infof - Store supplementary informational message
193 * @fc: The context in which to log the informational message
194 * @fmt: The format string
196 * Store the supplementary informational message for the process if the process
197 * has enabled the facility.
199 #define infof(fc, fmt, ...) __logfc(fc, 'i', fmt, ## __VA_ARGS__)
202 * warnf - Store supplementary warning message
203 * @fc: The context in which to log the error message
204 * @fmt: The format string
206 * Store the supplementary warning message for the process if the process has
207 * enabled the facility.
209 #define warnf(fc, fmt, ...) __logfc(fc, 'w', fmt, ## __VA_ARGS__)
212 * errorf - Store supplementary error message
213 * @fc: The context in which to log the error message
214 * @fmt: The format string
216 * Store the supplementary error message for the process if the process has
217 * enabled the facility.
219 #define errorf(fc, fmt, ...) __logfc(fc, 'e', fmt, ## __VA_ARGS__)
222 * invalf - Store supplementary invalid argument 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 and return -EINVAL.
229 #define invalf(fc, fmt, ...) (errorf(fc, fmt, ## __VA_ARGS__), -EINVAL)
231 #endif /* _LINUX_FS_CONTEXT_H */