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