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편집 파일: fs_context.h

/* SPDX-License-Identifier: GPL-2.0-or-later */ /* Filesystem superblock creation and reconfiguration context. * * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #ifndef _LINUX_FS_CONTEXT_H #define _LINUX_FS_CONTEXT_H #include <linux/kernel.h> #include <linux/refcount.h> #include <linux/errno.h> #include <linux/security.h> #include <linux/mutex.h> struct cred; struct dentry; struct file_operations; struct file_system_type; struct mnt_namespace; struct net; struct pid_namespace; struct super_block; struct user_namespace; struct vfsmount; struct path; enum fs_context_purpose { FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */ FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */ FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */ }; /* * Userspace usage phase for fsopen/fspick. */ enum fs_context_phase { FS_CONTEXT_CREATE_PARAMS, /* Loading params for sb creation */ FS_CONTEXT_CREATING, /* A superblock is being created */ FS_CONTEXT_AWAITING_MOUNT, /* Superblock created, awaiting fsmount() */ FS_CONTEXT_AWAITING_RECONF, /* Awaiting initialisation for reconfiguration */ FS_CONTEXT_RECONF_PARAMS, /* Loading params for reconfiguration */ FS_CONTEXT_RECONFIGURING, /* Reconfiguring the superblock */ FS_CONTEXT_FAILED, /* Failed to correctly transition a context */ }; /* * Type of parameter value. */ enum fs_value_type { fs_value_is_undefined, fs_value_is_flag, /* Value not given a value */ fs_value_is_string, /* Value is a string */ fs_value_is_blob, /* Value is a binary blob */ fs_value_is_filename, /* Value is a filename* + dirfd */ fs_value_is_file, /* Value is a file* */ }; /* * Configuration parameter. */ struct fs_parameter { const char *key; /* Parameter name */ enum fs_value_type type:8; /* The type of value here */ union { char *string; void *blob; struct filename *name; struct file *file; }; size_t size; int dirfd; }; struct p_log { const char *prefix; struct fc_log *log; }; /* * Filesystem context for holding the parameters used in the creation or * reconfiguration of a superblock. * * Superblock creation fills in ->root whereas reconfiguration begins with this * already set. * * See Documentation/filesystems/mount_api.rst */ struct fs_context { const struct fs_context_operations *ops; struct mutex uapi_mutex; /* Userspace access mutex */ struct file_system_type *fs_type; void *fs_private; /* The filesystem's context */ void *sget_key; struct dentry *root; /* The root and superblock */ struct user_namespace *user_ns; /* The user namespace for this mount */ struct net *net_ns; /* The network namespace for this mount */ const struct cred *cred; /* The mounter's credentials */ struct p_log log; /* Logging buffer */ const char *source; /* The source name (eg. dev path) */ void *security; /* Linux S&M options */ void *s_fs_info; /* Proposed s_fs_info */ unsigned int sb_flags; /* Proposed superblock flags (SB_*) */ unsigned int sb_flags_mask; /* Superblock flags that were changed */ unsigned int s_iflags; /* OR'd with sb->s_iflags */ unsigned int lsm_flags; /* Information flags from the fs to the LSM */ enum fs_context_purpose purpose:8; enum fs_context_phase phase:8; /* The phase the context is in */ bool need_free:1; /* Need to call ops->free() */ bool global:1; /* Goes into &init_user_ns */ bool oldapi:1; /* Coming from mount(2) */ }; struct fs_context_operations { void (*free)(struct fs_context *fc); int (*dup)(struct fs_context *fc, struct fs_context *src_fc); int (*parse_param)(struct fs_context *fc, struct fs_parameter *param); int (*parse_monolithic)(struct fs_context *fc, void *data); int (*get_tree)(struct fs_context *fc); int (*reconfigure)(struct fs_context *fc); }; /* * fs_context manipulation functions. */ extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type, unsigned int sb_flags); extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry, unsigned int sb_flags, unsigned int sb_flags_mask); extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type, struct dentry *reference); extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc); extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param); extern int vfs_parse_fs_string(struct fs_context *fc, const char *key, const char *value, size_t v_size); extern int generic_parse_monolithic(struct fs_context *fc, void *data); extern int vfs_get_tree(struct fs_context *fc); extern void put_fs_context(struct fs_context *fc); extern int vfs_parse_fs_param_source(struct fs_context *fc, struct fs_parameter *param); extern void fc_drop_locked(struct fs_context *fc); int reconfigure_single(struct super_block *s, int flags, void *data); /* * sget() wrappers to be called from the ->get_tree() op. */ enum vfs_get_super_keying { vfs_get_single_super, /* Only one such superblock may exist */ vfs_get_single_reconf_super, /* As above, but reconfigure if it exists */ vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */ vfs_get_independent_super, /* Multiple independent superblocks may exist */ }; extern int vfs_get_super(struct fs_context *fc, enum vfs_get_super_keying keying, int (*fill_super)(struct super_block *sb, struct fs_context *fc)); extern int get_tree_nodev(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc)); extern int get_tree_single(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc)); extern int get_tree_single_reconf(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc)); extern int get_tree_keyed(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc), void *key); int setup_bdev_super(struct super_block *sb, int sb_flags, struct fs_context *fc); extern int get_tree_bdev(struct fs_context *fc, int (*fill_super)(struct super_block *sb, struct fs_context *fc)); extern const struct file_operations fscontext_fops; /* * Mount error, warning and informational message logging. This structure is * shareable between a mount and a subordinate mount. */ struct fc_log { refcount_t usage; u8 head; /* Insertion index in buffer[] */ u8 tail; /* Removal index in buffer[] */ u8 need_free; /* Mask of kfree'able items in buffer[] */ struct module *owner; /* Owner module for strings that don't then need freeing */ char *buffer[8]; }; extern __attribute__((format(printf, 4, 5))) void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...); #define __logfc(fc, l, fmt, ...) logfc((fc)->log.log, NULL, \ l, fmt, ## __VA_ARGS__) #define __plog(p, l, fmt, ...) logfc((p)->log, (p)->prefix, \ l, fmt, ## __VA_ARGS__) /** * infof - Store supplementary informational message * @fc: The context in which to log the informational message * @fmt: The format string * * Store the supplementary informational message for the process if the process * has enabled the facility. */ #define infof(fc, fmt, ...) __logfc(fc, 'i', fmt, ## __VA_ARGS__) #define info_plog(p, fmt, ...) __plog(p, 'i', fmt, ## __VA_ARGS__) #define infofc(p, fmt, ...) __plog((&(fc)->log), 'i', fmt, ## __VA_ARGS__) /** * warnf - Store supplementary warning message * @fc: The context in which to log the error message * @fmt: The format string * * Store the supplementary warning message for the process if the process has * enabled the facility. */ #define warnf(fc, fmt, ...) __logfc(fc, 'w', fmt, ## __VA_ARGS__) #define warn_plog(p, fmt, ...) __plog(p, 'w', fmt, ## __VA_ARGS__) #define warnfc(fc, fmt, ...) __plog((&(fc)->log), 'w', fmt, ## __VA_ARGS__) /** * errorf - Store supplementary error message * @fc: The context in which to log the error message * @fmt: The format string * * Store the supplementary error message for the process if the process has * enabled the facility. */ #define errorf(fc, fmt, ...) __logfc(fc, 'e', fmt, ## __VA_ARGS__) #define error_plog(p, fmt, ...) __plog(p, 'e', fmt, ## __VA_ARGS__) #define errorfc(fc, fmt, ...) __plog((&(fc)->log), 'e', fmt, ## __VA_ARGS__) /** * invalf - Store supplementary invalid argument error message * @fc: The context in which to log the error message * @fmt: The format string * * Store the supplementary error message for the process if the process has * enabled the facility and return -EINVAL. */ #define invalf(fc, fmt, ...) (errorf(fc, fmt, ## __VA_ARGS__), -EINVAL) #define inval_plog(p, fmt, ...) (error_plog(p, fmt, ## __VA_ARGS__), -EINVAL) #define invalfc(fc, fmt, ...) (errorfc(fc, fmt, ## __VA_ARGS__), -EINVAL) #endif /* _LINUX_FS_CONTEXT_H */