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![Xin Yin](/assets/img/avatar_default.png)
For now, enqueuing and dequeuing on-demand requests all start from
idx 0, this makes request distribution unfair. In the weighty
concurrent I/O scenario, the request stored in higher idx will starve.
Searching requests cyclically in cachefiles_ondemand_daemon_read,
makes distribution fairer.
Fixes: c838305450
("cachefiles: notify the user daemon when looking up cookie")
Reported-by: Yongqing Li <liyongqing@bytedance.com>
Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220817065200.11543-1-yinxin.x@bytedance.com/ # v1
Link: https://lore.kernel.org/r/20220825020945.2293-1-yinxin.x@bytedance.com/ # v2
477 lines
14 KiB
C
477 lines
14 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* General netfs cache on cache files internal defs
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*
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* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#ifdef pr_fmt
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#undef pr_fmt
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#endif
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#define pr_fmt(fmt) "CacheFiles: " fmt
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#include <linux/fscache-cache.h>
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#include <linux/cred.h>
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#include <linux/security.h>
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#include <linux/xarray.h>
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#include <linux/cachefiles.h>
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#define CACHEFILES_DIO_BLOCK_SIZE 4096
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struct cachefiles_cache;
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struct cachefiles_object;
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enum cachefiles_content {
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/* These values are saved on disk */
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CACHEFILES_CONTENT_NO_DATA = 0, /* No content stored */
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CACHEFILES_CONTENT_SINGLE = 1, /* Content is monolithic, all is present */
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CACHEFILES_CONTENT_ALL = 2, /* Content is all present, no map */
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CACHEFILES_CONTENT_BACKFS_MAP = 3, /* Content is piecemeal, mapped through backing fs */
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CACHEFILES_CONTENT_DIRTY = 4, /* Content is dirty (only seen on disk) */
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nr__cachefiles_content
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};
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/*
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* Cached volume representation.
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*/
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struct cachefiles_volume {
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struct cachefiles_cache *cache;
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struct list_head cache_link; /* Link in cache->volumes */
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struct fscache_volume *vcookie; /* The netfs's representation */
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struct dentry *dentry; /* The volume dentry */
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struct dentry *fanout[256]; /* Fanout subdirs */
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};
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/*
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* Backing file state.
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*/
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struct cachefiles_object {
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struct fscache_cookie *cookie; /* Netfs data storage object cookie */
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struct cachefiles_volume *volume; /* Cache volume that holds this object */
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struct list_head cache_link; /* Link in cache->*_list */
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struct file *file; /* The file representing this object */
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char *d_name; /* Backing file name */
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int debug_id;
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spinlock_t lock;
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refcount_t ref;
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u8 d_name_len; /* Length of filename */
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enum cachefiles_content content_info:8; /* Info about content presence */
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unsigned long flags;
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#define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Have an unlinked tmpfile */
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#ifdef CONFIG_CACHEFILES_ONDEMAND
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int ondemand_id;
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#endif
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};
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#define CACHEFILES_ONDEMAND_ID_CLOSED -1
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/*
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* Cache files cache definition
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*/
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struct cachefiles_cache {
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struct fscache_cache *cache; /* Cache cookie */
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struct vfsmount *mnt; /* mountpoint holding the cache */
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struct dentry *store; /* Directory into which live objects go */
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struct dentry *graveyard; /* directory into which dead objects go */
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struct file *cachefilesd; /* manager daemon handle */
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struct list_head volumes; /* List of volume objects */
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struct list_head object_list; /* List of active objects */
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spinlock_t object_list_lock; /* Lock for volumes and object_list */
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const struct cred *cache_cred; /* security override for accessing cache */
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struct mutex daemon_mutex; /* command serialisation mutex */
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wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */
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atomic_t gravecounter; /* graveyard uniquifier */
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atomic_t f_released; /* number of objects released lately */
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atomic_long_t b_released; /* number of blocks released lately */
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atomic_long_t b_writing; /* Number of blocks being written */
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unsigned frun_percent; /* when to stop culling (% files) */
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unsigned fcull_percent; /* when to start culling (% files) */
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unsigned fstop_percent; /* when to stop allocating (% files) */
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unsigned brun_percent; /* when to stop culling (% blocks) */
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unsigned bcull_percent; /* when to start culling (% blocks) */
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unsigned bstop_percent; /* when to stop allocating (% blocks) */
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unsigned bsize; /* cache's block size */
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unsigned bshift; /* ilog2(bsize) */
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uint64_t frun; /* when to stop culling */
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uint64_t fcull; /* when to start culling */
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uint64_t fstop; /* when to stop allocating */
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sector_t brun; /* when to stop culling */
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sector_t bcull; /* when to start culling */
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sector_t bstop; /* when to stop allocating */
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unsigned long flags;
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#define CACHEFILES_READY 0 /* T if cache prepared */
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#define CACHEFILES_DEAD 1 /* T if cache dead */
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#define CACHEFILES_CULLING 2 /* T if cull engaged */
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#define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */
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#define CACHEFILES_ONDEMAND_MODE 4 /* T if in on-demand read mode */
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char *rootdirname; /* name of cache root directory */
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char *secctx; /* LSM security context */
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char *tag; /* cache binding tag */
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refcount_t unbind_pincount;/* refcount to do daemon unbind */
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struct xarray reqs; /* xarray of pending on-demand requests */
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unsigned long req_id_next;
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struct xarray ondemand_ids; /* xarray for ondemand_id allocation */
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u32 ondemand_id_next;
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};
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static inline bool cachefiles_in_ondemand_mode(struct cachefiles_cache *cache)
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{
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return IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND) &&
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test_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
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}
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struct cachefiles_req {
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struct cachefiles_object *object;
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struct completion done;
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int error;
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struct cachefiles_msg msg;
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};
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#define CACHEFILES_REQ_NEW XA_MARK_1
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#include <trace/events/cachefiles.h>
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static inline
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struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
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{
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return cres->cache_priv2;
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}
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static inline
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struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
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{
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return fscache_cres_cookie(cres)->cache_priv;
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}
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/*
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* note change of state for daemon
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*/
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static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
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{
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set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
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wake_up_all(&cache->daemon_pollwq);
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}
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/*
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* cache.c
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*/
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extern int cachefiles_add_cache(struct cachefiles_cache *cache);
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extern void cachefiles_withdraw_cache(struct cachefiles_cache *cache);
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enum cachefiles_has_space_for {
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cachefiles_has_space_check,
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cachefiles_has_space_for_write,
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cachefiles_has_space_for_create,
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};
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extern int cachefiles_has_space(struct cachefiles_cache *cache,
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unsigned fnr, unsigned bnr,
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enum cachefiles_has_space_for reason);
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/*
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* daemon.c
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*/
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extern const struct file_operations cachefiles_daemon_fops;
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extern void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache);
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extern void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache);
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/*
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* error_inject.c
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*/
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#ifdef CONFIG_CACHEFILES_ERROR_INJECTION
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extern unsigned int cachefiles_error_injection_state;
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extern int cachefiles_register_error_injection(void);
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extern void cachefiles_unregister_error_injection(void);
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#else
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#define cachefiles_error_injection_state 0
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static inline int cachefiles_register_error_injection(void)
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{
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return 0;
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}
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static inline void cachefiles_unregister_error_injection(void)
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{
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}
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#endif
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static inline int cachefiles_inject_read_error(void)
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{
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return cachefiles_error_injection_state & 2 ? -EIO : 0;
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}
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static inline int cachefiles_inject_write_error(void)
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{
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return cachefiles_error_injection_state & 2 ? -EIO :
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cachefiles_error_injection_state & 1 ? -ENOSPC :
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0;
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}
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static inline int cachefiles_inject_remove_error(void)
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{
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return cachefiles_error_injection_state & 2 ? -EIO : 0;
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}
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/*
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* interface.c
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*/
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extern const struct fscache_cache_ops cachefiles_cache_ops;
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extern void cachefiles_see_object(struct cachefiles_object *object,
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enum cachefiles_obj_ref_trace why);
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extern struct cachefiles_object *cachefiles_grab_object(struct cachefiles_object *object,
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enum cachefiles_obj_ref_trace why);
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extern void cachefiles_put_object(struct cachefiles_object *object,
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enum cachefiles_obj_ref_trace why);
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/*
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* io.c
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*/
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extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
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enum fscache_want_state want_state);
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extern int __cachefiles_prepare_write(struct cachefiles_object *object,
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struct file *file,
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loff_t *_start, size_t *_len,
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bool no_space_allocated_yet);
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extern int __cachefiles_write(struct cachefiles_object *object,
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struct file *file,
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loff_t start_pos,
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struct iov_iter *iter,
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netfs_io_terminated_t term_func,
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void *term_func_priv);
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/*
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* key.c
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*/
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extern bool cachefiles_cook_key(struct cachefiles_object *object);
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/*
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* main.c
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*/
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extern struct kmem_cache *cachefiles_object_jar;
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/*
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* namei.c
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*/
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extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
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struct file *file);
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extern int cachefiles_bury_object(struct cachefiles_cache *cache,
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struct cachefiles_object *object,
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struct dentry *dir,
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struct dentry *rep,
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enum fscache_why_object_killed why);
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extern int cachefiles_delete_object(struct cachefiles_object *object,
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enum fscache_why_object_killed why);
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extern bool cachefiles_look_up_object(struct cachefiles_object *object);
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extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
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struct dentry *dir,
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const char *name,
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bool *_is_new);
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extern void cachefiles_put_directory(struct dentry *dir);
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extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
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char *filename);
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extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
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struct dentry *dir, char *filename);
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extern struct file *cachefiles_create_tmpfile(struct cachefiles_object *object);
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extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
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struct cachefiles_object *object);
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/*
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* ondemand.c
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*/
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#ifdef CONFIG_CACHEFILES_ONDEMAND
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extern ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
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char __user *_buffer, size_t buflen);
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extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
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char *args);
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extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
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extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
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extern int cachefiles_ondemand_read(struct cachefiles_object *object,
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loff_t pos, size_t len);
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#else
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static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
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char __user *_buffer, size_t buflen)
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{
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return -EOPNOTSUPP;
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}
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static inline int cachefiles_ondemand_init_object(struct cachefiles_object *object)
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{
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return 0;
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}
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static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
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{
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}
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static inline int cachefiles_ondemand_read(struct cachefiles_object *object,
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loff_t pos, size_t len)
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{
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return -EOPNOTSUPP;
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}
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#endif
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/*
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* security.c
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*/
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extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
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extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
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struct dentry *root,
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const struct cred **_saved_cred);
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static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
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const struct cred **_saved_cred)
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{
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*_saved_cred = override_creds(cache->cache_cred);
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}
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static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
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const struct cred *saved_cred)
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{
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revert_creds(saved_cred);
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}
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/*
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* volume.c
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*/
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void cachefiles_acquire_volume(struct fscache_volume *volume);
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void cachefiles_free_volume(struct fscache_volume *volume);
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void cachefiles_withdraw_volume(struct cachefiles_volume *volume);
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/*
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* xattr.c
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*/
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extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
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extern int cachefiles_check_auxdata(struct cachefiles_object *object,
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struct file *file);
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extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
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struct cachefiles_object *object,
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struct dentry *dentry);
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extern void cachefiles_prepare_to_write(struct fscache_cookie *cookie);
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extern bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume);
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extern int cachefiles_check_volume_xattr(struct cachefiles_volume *volume);
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/*
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* Error handling
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*/
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#define cachefiles_io_error(___cache, FMT, ...) \
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do { \
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pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
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fscache_io_error((___cache)->cache); \
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set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
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} while (0)
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#define cachefiles_io_error_obj(object, FMT, ...) \
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do { \
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struct cachefiles_cache *___cache; \
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\
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___cache = (object)->volume->cache; \
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cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__, \
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(object)->debug_id); \
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} while (0)
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/*
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* Debug tracing
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*/
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extern unsigned cachefiles_debug;
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#define CACHEFILES_DEBUG_KENTER 1
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#define CACHEFILES_DEBUG_KLEAVE 2
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#define CACHEFILES_DEBUG_KDEBUG 4
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#define dbgprintk(FMT, ...) \
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printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
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#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
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#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
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#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
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#if defined(__KDEBUG)
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#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
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#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
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#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
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#elif defined(CONFIG_CACHEFILES_DEBUG)
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#define _enter(FMT, ...) \
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do { \
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if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
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kenter(FMT, ##__VA_ARGS__); \
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} while (0)
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#define _leave(FMT, ...) \
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do { \
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if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
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kleave(FMT, ##__VA_ARGS__); \
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} while (0)
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#define _debug(FMT, ...) \
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do { \
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if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
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kdebug(FMT, ##__VA_ARGS__); \
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} while (0)
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#else
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#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
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#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
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#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
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#endif
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#if 1 /* defined(__KDEBUGALL) */
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#define ASSERT(X) \
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do { \
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if (unlikely(!(X))) { \
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pr_err("\n"); \
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pr_err("Assertion failed\n"); \
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BUG(); \
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} \
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} while (0)
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#define ASSERTCMP(X, OP, Y) \
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do { \
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if (unlikely(!((X) OP (Y)))) { \
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pr_err("\n"); \
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pr_err("Assertion failed\n"); \
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pr_err("%lx " #OP " %lx is false\n", \
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(unsigned long)(X), (unsigned long)(Y)); \
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BUG(); \
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} \
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} while (0)
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#define ASSERTIF(C, X) \
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do { \
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if (unlikely((C) && !(X))) { \
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pr_err("\n"); \
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pr_err("Assertion failed\n"); \
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BUG(); \
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} \
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} while (0)
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#define ASSERTIFCMP(C, X, OP, Y) \
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do { \
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if (unlikely((C) && !((X) OP (Y)))) { \
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pr_err("\n"); \
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pr_err("Assertion failed\n"); \
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pr_err("%lx " #OP " %lx is false\n", \
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(unsigned long)(X), (unsigned long)(Y)); \
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BUG(); \
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} \
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} while (0)
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#else
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#define ASSERT(X) do {} while (0)
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#define ASSERTCMP(X, OP, Y) do {} while (0)
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#define ASSERTIF(C, X) do {} while (0)
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#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
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#endif
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