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https://github.com/torvalds/linux
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fscache: Implement cookie invalidation
Add a function to invalidate the cache behind a cookie: void fscache_invalidate(struct fscache_cookie *cookie, const void *aux_data, loff_t size, unsigned int flags) This causes any cached data for the specified cookie to be discarded. If the cookie is marked as being in use, a new cache object will be created if possible and future I/O will use that instead. In-flight I/O should be abandoned (writes) or reconsidered (reads). Each time it is called cookie->inval_counter is incremented and this can be used to detect invalidation at the end of an I/O operation. The coherency data attached to the cookie can be updated and the cookie size should be reset. One flag is available, FSCACHE_INVAL_DIO_WRITE, which should be used to indicate invalidation due to a DIO write on a file. This will temporarily disable caching for this cookie. Changes ======= ver #2: - Should only change to inval state if can get access to cache. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819602231.215744.11206598147269491575.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906909707.143852.18056070560477964891.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967107447.1823006.5945029409592119962.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021512640.640689.11418616313147754172.stgit@warthog.procyon.org.uk/ # v4
This commit is contained in:
David Howells
parent
12bb21a29c
commit
d24af13e2e
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@ -19,6 +19,7 @@ static void fscache_cookie_lru_timed_out(struct timer_list *timer);
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static void fscache_cookie_lru_worker(struct work_struct *work);
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static void fscache_cookie_worker(struct work_struct *work);
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static void fscache_unhash_cookie(struct fscache_cookie *cookie);
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static void fscache_perform_invalidation(struct fscache_cookie *cookie);
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#define fscache_cookie_hash_shift 15
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static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift];
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@ -28,7 +29,7 @@ static LIST_HEAD(fscache_cookie_lru);
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static DEFINE_SPINLOCK(fscache_cookie_lru_lock);
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DEFINE_TIMER(fscache_cookie_lru_timer, fscache_cookie_lru_timed_out);
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static DECLARE_WORK(fscache_cookie_lru_work, fscache_cookie_lru_worker);
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static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAFUWRD";
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static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAIFUWRD";
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unsigned int fscache_lru_cookie_timeout = 10 * HZ;
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void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
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@ -236,6 +237,19 @@ void fscache_cookie_lookup_negative(struct fscache_cookie *cookie)
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}
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EXPORT_SYMBOL(fscache_cookie_lookup_negative);
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/**
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* fscache_resume_after_invalidation - Allow I/O to resume after invalidation
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* @cookie: The cookie that was invalidated
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*
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* Tell fscache that invalidation is sufficiently complete that I/O can be
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* allowed again.
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*/
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void fscache_resume_after_invalidation(struct fscache_cookie *cookie)
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{
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fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_ACTIVE);
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}
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EXPORT_SYMBOL(fscache_resume_after_invalidation);
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/**
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* fscache_caching_failed - Report that a failure stopped caching on a cookie
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* @cookie: The cookie that was affected
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@ -566,6 +580,7 @@ void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify)
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set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags);
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break;
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case FSCACHE_COOKIE_STATE_ACTIVE:
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case FSCACHE_COOKIE_STATE_INVALIDATING:
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if (will_modify &&
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!test_and_set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags)) {
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set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
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@ -671,6 +686,11 @@ static void fscache_cookie_state_machine(struct fscache_cookie *cookie)
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fscache_perform_lookup(cookie);
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goto again;
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case FSCACHE_COOKIE_STATE_INVALIDATING:
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spin_unlock(&cookie->lock);
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fscache_perform_invalidation(cookie);
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goto again;
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case FSCACHE_COOKIE_STATE_ACTIVE:
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if (test_and_clear_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags)) {
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spin_unlock(&cookie->lock);
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@ -962,6 +982,72 @@ struct fscache_cookie *fscache_get_cookie(struct fscache_cookie *cookie,
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}
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EXPORT_SYMBOL(fscache_get_cookie);
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/*
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* Ask the cache to effect invalidation of a cookie.
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*/
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static void fscache_perform_invalidation(struct fscache_cookie *cookie)
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{
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if (!cookie->volume->cache->ops->invalidate_cookie(cookie))
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fscache_caching_failed(cookie);
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fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end);
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}
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/*
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* Invalidate an object.
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*/
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void __fscache_invalidate(struct fscache_cookie *cookie,
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const void *aux_data, loff_t new_size,
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unsigned int flags)
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{
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bool is_caching;
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_enter("c=%x", cookie->debug_id);
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fscache_stat(&fscache_n_invalidates);
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if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
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"Trying to invalidate relinquished cookie\n"))
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return;
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if ((flags & FSCACHE_INVAL_DIO_WRITE) &&
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test_and_set_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags))
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return;
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spin_lock(&cookie->lock);
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set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
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fscache_update_aux(cookie, aux_data, &new_size);
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cookie->inval_counter++;
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trace_fscache_invalidate(cookie, new_size);
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switch (cookie->state) {
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case FSCACHE_COOKIE_STATE_INVALIDATING: /* is_still_valid will catch it */
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default:
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spin_unlock(&cookie->lock);
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_leave(" [no %u]", cookie->state);
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return;
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case FSCACHE_COOKIE_STATE_LOOKING_UP:
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case FSCACHE_COOKIE_STATE_CREATING:
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spin_unlock(&cookie->lock);
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_leave(" [look %x]", cookie->inval_counter);
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return;
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case FSCACHE_COOKIE_STATE_ACTIVE:
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is_caching = fscache_begin_cookie_access(
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cookie, fscache_access_invalidate_cookie);
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if (is_caching)
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__fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_INVALIDATING);
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spin_unlock(&cookie->lock);
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wake_up_cookie_state(cookie);
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if (is_caching)
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fscache_queue_cookie(cookie, fscache_cookie_get_inval_work);
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_leave(" [inv]");
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return;
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}
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}
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EXPORT_SYMBOL(__fscache_invalidate);
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/*
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* Generate a list of extant cookies in /proc/fs/fscache/cookies
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*/
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@ -105,6 +105,8 @@ extern atomic_t fscache_n_acquires;
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extern atomic_t fscache_n_acquires_ok;
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extern atomic_t fscache_n_acquires_oom;
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extern atomic_t fscache_n_invalidates;
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extern atomic_t fscache_n_relinquishes;
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extern atomic_t fscache_n_relinquishes_retire;
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extern atomic_t fscache_n_relinquishes_dropped;
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@ -26,6 +26,8 @@ atomic_t fscache_n_acquires;
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atomic_t fscache_n_acquires_ok;
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atomic_t fscache_n_acquires_oom;
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atomic_t fscache_n_invalidates;
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atomic_t fscache_n_updates;
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EXPORT_SYMBOL(fscache_n_updates);
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@ -59,6 +61,9 @@ int fscache_stats_show(struct seq_file *m, void *v)
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timer_pending(&fscache_cookie_lru_timer) ?
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fscache_cookie_lru_timer.expires - jiffies : 0);
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seq_printf(m, "Invals : n=%u\n",
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atomic_read(&fscache_n_invalidates));
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seq_printf(m, "Updates: n=%u\n",
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atomic_read(&fscache_n_updates));
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@ -64,6 +64,9 @@ struct fscache_cache_ops {
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/* Withdraw an object without any cookie access counts held */
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void (*withdraw_cookie)(struct fscache_cookie *cookie);
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/* Invalidate an object */
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bool (*invalidate_cookie)(struct fscache_cookie *cookie);
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/* Prepare to write to a live cache object */
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void (*prepare_to_write)(struct fscache_cookie *cookie);
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};
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@ -96,6 +99,7 @@ extern void fscache_put_cookie(struct fscache_cookie *cookie,
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extern void fscache_end_cookie_access(struct fscache_cookie *cookie,
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enum fscache_access_trace why);
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extern void fscache_cookie_lookup_negative(struct fscache_cookie *cookie);
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extern void fscache_resume_after_invalidation(struct fscache_cookie *cookie);
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extern void fscache_caching_failed(struct fscache_cookie *cookie);
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/**
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@ -39,6 +39,8 @@ struct fscache_cookie;
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#define FSCACHE_ADV_WRITE_CACHE 0x00 /* Do cache if written to locally */
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#define FSCACHE_ADV_WRITE_NOCACHE 0x02 /* Don't cache if written to locally */
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#define FSCACHE_INVAL_DIO_WRITE 0x01 /* Invalidate due to DIO write */
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/*
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* Data object state.
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*/
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@ -47,6 +49,7 @@ enum fscache_cookie_state {
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FSCACHE_COOKIE_STATE_LOOKING_UP, /* The cache object is being looked up */
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FSCACHE_COOKIE_STATE_CREATING, /* The cache object is being created */
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FSCACHE_COOKIE_STATE_ACTIVE, /* The cache is active, readable and writable */
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FSCACHE_COOKIE_STATE_INVALIDATING, /* The cache is being invalidated */
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FSCACHE_COOKIE_STATE_FAILED, /* The cache failed, withdraw to clear */
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FSCACHE_COOKIE_STATE_LRU_DISCARDING, /* The cookie is being discarded by the LRU */
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FSCACHE_COOKIE_STATE_WITHDRAWING, /* The cookie is being withdrawn */
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@ -153,6 +156,7 @@ extern struct fscache_cookie *__fscache_acquire_cookie(
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extern void __fscache_use_cookie(struct fscache_cookie *, bool);
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extern void __fscache_unuse_cookie(struct fscache_cookie *, const void *, const loff_t *);
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extern void __fscache_relinquish_cookie(struct fscache_cookie *, bool);
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extern void __fscache_invalidate(struct fscache_cookie *, const void *, loff_t, unsigned int);
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/**
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* fscache_acquire_volume - Register a volume as desiring caching services
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@ -327,4 +331,31 @@ void __fscache_update_cookie(struct fscache_cookie *cookie, const void *aux_data
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set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
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}
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/**
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* fscache_invalidate - Notify cache that an object needs invalidation
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* @cookie: The cookie representing the cache object
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* @aux_data: The updated auxiliary data for the cookie (may be NULL)
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* @size: The revised size of the object.
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* @flags: Invalidation flags (FSCACHE_INVAL_*)
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*
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* Notify the cache that an object is needs to be invalidated and that it
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* should abort any retrievals or stores it is doing on the cache. This
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* increments inval_counter on the cookie which can be used by the caller to
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* reconsider I/O requests as they complete.
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*
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* If @flags has FSCACHE_INVAL_DIO_WRITE set, this indicates that this is due
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* to a direct I/O write and will cause caching to be disabled on this cookie
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* until it is completely unused.
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*
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* See Documentation/filesystems/caching/netfs-api.rst for a complete
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* description.
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*/
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static inline
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void fscache_invalidate(struct fscache_cookie *cookie,
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const void *aux_data, loff_t size, unsigned int flags)
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{
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if (fscache_cookie_enabled(cookie))
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__fscache_invalidate(cookie, aux_data, size, flags);
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}
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#endif /* _LINUX_FSCACHE_H */
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@ -124,6 +124,7 @@ struct netfs_cache_resources {
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void *cache_priv;
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void *cache_priv2;
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unsigned int debug_id; /* Cookie debug ID */
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unsigned int inval_counter; /* object->inval_counter at begin_op */
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};
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/*
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@ -51,6 +51,7 @@ enum fscache_cookie_trace {
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fscache_cookie_discard,
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fscache_cookie_get_end_access,
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fscache_cookie_get_hash_collision,
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fscache_cookie_get_inval_work,
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fscache_cookie_get_lru,
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fscache_cookie_get_use_work,
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fscache_cookie_new_acquire,
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@ -73,6 +74,8 @@ enum fscache_access_trace {
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fscache_access_acquire_volume_end,
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fscache_access_cache_pin,
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fscache_access_cache_unpin,
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fscache_access_invalidate_cookie,
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fscache_access_invalidate_cookie_end,
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fscache_access_lookup_cookie,
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fscache_access_lookup_cookie_end,
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fscache_access_lookup_cookie_end_failed,
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@ -116,6 +119,7 @@ enum fscache_access_trace {
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EM(fscache_cookie_discard, "DISCARD ") \
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EM(fscache_cookie_get_hash_collision, "GET hcoll") \
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EM(fscache_cookie_get_end_access, "GQ endac") \
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EM(fscache_cookie_get_inval_work, "GQ inval") \
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EM(fscache_cookie_get_lru, "GET lru ") \
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EM(fscache_cookie_get_use_work, "GQ use ") \
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EM(fscache_cookie_new_acquire, "NEW acq ") \
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@ -137,6 +141,8 @@ enum fscache_access_trace {
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EM(fscache_access_acquire_volume_end, "END acq_vol") \
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EM(fscache_access_cache_pin, "PIN cache ") \
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EM(fscache_access_cache_unpin, "UNPIN cache ") \
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EM(fscache_access_invalidate_cookie, "BEGIN inval ") \
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EM(fscache_access_invalidate_cookie_end,"END inval ") \
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EM(fscache_access_lookup_cookie, "BEGIN lookup ") \
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EM(fscache_access_lookup_cookie_end, "END lookup ") \
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EM(fscache_access_lookup_cookie_end_failed,"END lookupf") \
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@ -385,6 +391,25 @@ TRACE_EVENT(fscache_relinquish,
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__entry->n_active, __entry->flags, __entry->retire)
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);
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TRACE_EVENT(fscache_invalidate,
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TP_PROTO(struct fscache_cookie *cookie, loff_t new_size),
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TP_ARGS(cookie, new_size),
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TP_STRUCT__entry(
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__field(unsigned int, cookie )
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__field(loff_t, new_size )
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),
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TP_fast_assign(
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__entry->cookie = cookie->debug_id;
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__entry->new_size = new_size;
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),
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TP_printk("c=%08x sz=%llx",
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__entry->cookie, __entry->new_size)
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);
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#endif /* _TRACE_FSCACHE_H */
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/* This part must be outside protection */
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