1d64f4554SDavid Howells // SPDX-License-Identifier: GPL-2.0-or-later 2d64f4554SDavid Howells /* Cache data I/O routines 3d64f4554SDavid Howells * 4d64f4554SDavid Howells * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. 5d64f4554SDavid Howells * Written by David Howells (dhowells@redhat.com) 6d64f4554SDavid Howells */ 7d64f4554SDavid Howells #define FSCACHE_DEBUG_LEVEL OPERATION 8d64f4554SDavid Howells #include <linux/fscache-cache.h> 9d64f4554SDavid Howells #include <linux/uio.h> 10d64f4554SDavid Howells #include <linux/bvec.h> 11d64f4554SDavid Howells #include <linux/slab.h> 12d64f4554SDavid Howells #include <linux/uio.h> 13d64f4554SDavid Howells #include "internal.h" 14d64f4554SDavid Howells 15d64f4554SDavid Howells /** 16d64f4554SDavid Howells * fscache_wait_for_operation - Wait for an object become accessible 17d64f4554SDavid Howells * @cres: The cache resources for the operation being performed 18d64f4554SDavid Howells * @want_state: The minimum state the object must be at 19d64f4554SDavid Howells * 20d64f4554SDavid Howells * See if the target cache object is at the specified minimum state of 21d64f4554SDavid Howells * accessibility yet, and if not, wait for it. 22d64f4554SDavid Howells */ 23d64f4554SDavid Howells bool fscache_wait_for_operation(struct netfs_cache_resources *cres, 24d64f4554SDavid Howells enum fscache_want_state want_state) 25d64f4554SDavid Howells { 26d64f4554SDavid Howells struct fscache_cookie *cookie = fscache_cres_cookie(cres); 27d64f4554SDavid Howells enum fscache_cookie_state state; 28d64f4554SDavid Howells 29d64f4554SDavid Howells again: 30d64f4554SDavid Howells if (!fscache_cache_is_live(cookie->volume->cache)) { 31d64f4554SDavid Howells _leave(" [broken]"); 32d64f4554SDavid Howells return false; 33d64f4554SDavid Howells } 34d64f4554SDavid Howells 35d64f4554SDavid Howells state = fscache_cookie_state(cookie); 36d64f4554SDavid Howells _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state); 37d64f4554SDavid Howells 38d64f4554SDavid Howells switch (state) { 39d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_CREATING: 40d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_INVALIDATING: 41d64f4554SDavid Howells if (want_state == FSCACHE_WANT_PARAMS) 42d64f4554SDavid Howells goto ready; /* There can be no content */ 43d64f4554SDavid Howells fallthrough; 44d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_LOOKING_UP: 45d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_LRU_DISCARDING: 46d64f4554SDavid Howells wait_var_event(&cookie->state, 47d64f4554SDavid Howells fscache_cookie_state(cookie) != state); 48d64f4554SDavid Howells goto again; 49d64f4554SDavid Howells 50d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_ACTIVE: 51d64f4554SDavid Howells goto ready; 52d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_DROPPED: 53d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_RELINQUISHING: 54d64f4554SDavid Howells default: 55d64f4554SDavid Howells _leave(" [not live]"); 56d64f4554SDavid Howells return false; 57d64f4554SDavid Howells } 58d64f4554SDavid Howells 59d64f4554SDavid Howells ready: 60d64f4554SDavid Howells if (!cres->cache_priv2) 61d64f4554SDavid Howells return cookie->volume->cache->ops->begin_operation(cres, want_state); 62d64f4554SDavid Howells return true; 63d64f4554SDavid Howells } 64d64f4554SDavid Howells EXPORT_SYMBOL(fscache_wait_for_operation); 65d64f4554SDavid Howells 66d64f4554SDavid Howells /* 67d64f4554SDavid Howells * Begin an I/O operation on the cache, waiting till we reach the right state. 68d64f4554SDavid Howells * 69d64f4554SDavid Howells * Attaches the resources required to the operation resources record. 70d64f4554SDavid Howells */ 71d64f4554SDavid Howells static int fscache_begin_operation(struct netfs_cache_resources *cres, 72d64f4554SDavid Howells struct fscache_cookie *cookie, 73d64f4554SDavid Howells enum fscache_want_state want_state, 74d64f4554SDavid Howells enum fscache_access_trace why) 75d64f4554SDavid Howells { 76d64f4554SDavid Howells enum fscache_cookie_state state; 77d64f4554SDavid Howells long timeo; 78d64f4554SDavid Howells bool once_only = false; 79d64f4554SDavid Howells 80d64f4554SDavid Howells cres->ops = NULL; 81d64f4554SDavid Howells cres->cache_priv = cookie; 82d64f4554SDavid Howells cres->cache_priv2 = NULL; 83d64f4554SDavid Howells cres->debug_id = cookie->debug_id; 84d64f4554SDavid Howells cres->inval_counter = cookie->inval_counter; 85d64f4554SDavid Howells 86d64f4554SDavid Howells if (!fscache_begin_cookie_access(cookie, why)) 87d64f4554SDavid Howells return -ENOBUFS; 88d64f4554SDavid Howells 89d64f4554SDavid Howells again: 90d64f4554SDavid Howells spin_lock(&cookie->lock); 91d64f4554SDavid Howells 92d64f4554SDavid Howells state = fscache_cookie_state(cookie); 93d64f4554SDavid Howells _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state); 94d64f4554SDavid Howells 95d64f4554SDavid Howells switch (state) { 96d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_LOOKING_UP: 97d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_LRU_DISCARDING: 98d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_INVALIDATING: 99d64f4554SDavid Howells goto wait_for_file_wrangling; 100d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_CREATING: 101d64f4554SDavid Howells if (want_state == FSCACHE_WANT_PARAMS) 102d64f4554SDavid Howells goto ready; /* There can be no content */ 103d64f4554SDavid Howells goto wait_for_file_wrangling; 104d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_ACTIVE: 105d64f4554SDavid Howells goto ready; 106d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_DROPPED: 107d64f4554SDavid Howells case FSCACHE_COOKIE_STATE_RELINQUISHING: 108d64f4554SDavid Howells WARN(1, "Can't use cookie in state %u\n", cookie->state); 109d64f4554SDavid Howells goto not_live; 110d64f4554SDavid Howells default: 111d64f4554SDavid Howells goto not_live; 112d64f4554SDavid Howells } 113d64f4554SDavid Howells 114d64f4554SDavid Howells ready: 115d64f4554SDavid Howells spin_unlock(&cookie->lock); 116d64f4554SDavid Howells if (!cookie->volume->cache->ops->begin_operation(cres, want_state)) 117d64f4554SDavid Howells goto failed; 118d64f4554SDavid Howells return 0; 119d64f4554SDavid Howells 120d64f4554SDavid Howells wait_for_file_wrangling: 121d64f4554SDavid Howells spin_unlock(&cookie->lock); 122d64f4554SDavid Howells trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref), 123d64f4554SDavid Howells atomic_read(&cookie->n_accesses), 124d64f4554SDavid Howells fscache_access_io_wait); 125d64f4554SDavid Howells timeo = wait_var_event_timeout(&cookie->state, 126d64f4554SDavid Howells fscache_cookie_state(cookie) != state, 20 * HZ); 127d64f4554SDavid Howells if (timeo <= 1 && !once_only) { 128d64f4554SDavid Howells pr_warn("%s: cookie state change wait timed out: cookie->state=%u state=%u", 129d64f4554SDavid Howells __func__, fscache_cookie_state(cookie), state); 130d64f4554SDavid Howells fscache_print_cookie(cookie, 'O'); 131d64f4554SDavid Howells once_only = true; 132d64f4554SDavid Howells } 133d64f4554SDavid Howells goto again; 134d64f4554SDavid Howells 135d64f4554SDavid Howells not_live: 136d64f4554SDavid Howells spin_unlock(&cookie->lock); 137d64f4554SDavid Howells failed: 138d64f4554SDavid Howells cres->cache_priv = NULL; 139d64f4554SDavid Howells cres->ops = NULL; 140d64f4554SDavid Howells fscache_end_cookie_access(cookie, fscache_access_io_not_live); 141d64f4554SDavid Howells _leave(" = -ENOBUFS"); 142d64f4554SDavid Howells return -ENOBUFS; 143d64f4554SDavid Howells } 144d64f4554SDavid Howells 145d64f4554SDavid Howells int __fscache_begin_read_operation(struct netfs_cache_resources *cres, 146d64f4554SDavid Howells struct fscache_cookie *cookie) 147d64f4554SDavid Howells { 148d64f4554SDavid Howells return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS, 149d64f4554SDavid Howells fscache_access_io_read); 150d64f4554SDavid Howells } 151d64f4554SDavid Howells EXPORT_SYMBOL(__fscache_begin_read_operation); 152b6e16652SDavid Howells 153*08276bdaSDavid Howells /** 154*08276bdaSDavid Howells * fscache_set_page_dirty - Mark page dirty and pin a cache object for writeback 155*08276bdaSDavid Howells * @page: The page being dirtied 156*08276bdaSDavid Howells * @cookie: The cookie referring to the cache object 157*08276bdaSDavid Howells * 158*08276bdaSDavid Howells * Set the dirty flag on a page and pin an in-use cache object in memory when 159*08276bdaSDavid Howells * dirtying a page so that writeback can later write to it. This is intended 160*08276bdaSDavid Howells * to be called from the filesystem's ->set_page_dirty() method. 161*08276bdaSDavid Howells * 162*08276bdaSDavid Howells * Returns 1 if PG_dirty was set on the page, 0 otherwise. 163*08276bdaSDavid Howells */ 164*08276bdaSDavid Howells int fscache_set_page_dirty(struct page *page, struct fscache_cookie *cookie) 165*08276bdaSDavid Howells { 166*08276bdaSDavid Howells struct inode *inode = page->mapping->host; 167*08276bdaSDavid Howells bool need_use = false; 168*08276bdaSDavid Howells 169*08276bdaSDavid Howells _enter(""); 170*08276bdaSDavid Howells 171*08276bdaSDavid Howells if (!__set_page_dirty_nobuffers(page)) 172*08276bdaSDavid Howells return 0; 173*08276bdaSDavid Howells if (!fscache_cookie_valid(cookie)) 174*08276bdaSDavid Howells return 1; 175*08276bdaSDavid Howells 176*08276bdaSDavid Howells if (!(inode->i_state & I_PINNING_FSCACHE_WB)) { 177*08276bdaSDavid Howells spin_lock(&inode->i_lock); 178*08276bdaSDavid Howells if (!(inode->i_state & I_PINNING_FSCACHE_WB)) { 179*08276bdaSDavid Howells inode->i_state |= I_PINNING_FSCACHE_WB; 180*08276bdaSDavid Howells need_use = true; 181*08276bdaSDavid Howells } 182*08276bdaSDavid Howells spin_unlock(&inode->i_lock); 183*08276bdaSDavid Howells 184*08276bdaSDavid Howells if (need_use) 185*08276bdaSDavid Howells fscache_use_cookie(cookie, true); 186*08276bdaSDavid Howells } 187*08276bdaSDavid Howells return 1; 188*08276bdaSDavid Howells } 189*08276bdaSDavid Howells EXPORT_SYMBOL(fscache_set_page_dirty); 190*08276bdaSDavid Howells 191b6e16652SDavid Howells struct fscache_write_request { 192b6e16652SDavid Howells struct netfs_cache_resources cache_resources; 193b6e16652SDavid Howells struct address_space *mapping; 194b6e16652SDavid Howells loff_t start; 195b6e16652SDavid Howells size_t len; 196b6e16652SDavid Howells bool set_bits; 197b6e16652SDavid Howells netfs_io_terminated_t term_func; 198b6e16652SDavid Howells void *term_func_priv; 199b6e16652SDavid Howells }; 200b6e16652SDavid Howells 201b6e16652SDavid Howells void __fscache_clear_page_bits(struct address_space *mapping, 202b6e16652SDavid Howells loff_t start, size_t len) 203b6e16652SDavid Howells { 204b6e16652SDavid Howells pgoff_t first = start / PAGE_SIZE; 205b6e16652SDavid Howells pgoff_t last = (start + len - 1) / PAGE_SIZE; 206b6e16652SDavid Howells struct page *page; 207b6e16652SDavid Howells 208b6e16652SDavid Howells if (len) { 209b6e16652SDavid Howells XA_STATE(xas, &mapping->i_pages, first); 210b6e16652SDavid Howells 211b6e16652SDavid Howells rcu_read_lock(); 212b6e16652SDavid Howells xas_for_each(&xas, page, last) { 213b6e16652SDavid Howells end_page_fscache(page); 214b6e16652SDavid Howells } 215b6e16652SDavid Howells rcu_read_unlock(); 216b6e16652SDavid Howells } 217b6e16652SDavid Howells } 218b6e16652SDavid Howells EXPORT_SYMBOL(__fscache_clear_page_bits); 219b6e16652SDavid Howells 220b6e16652SDavid Howells /* 221b6e16652SDavid Howells * Deal with the completion of writing the data to the cache. 222b6e16652SDavid Howells */ 223b6e16652SDavid Howells static void fscache_wreq_done(void *priv, ssize_t transferred_or_error, 224b6e16652SDavid Howells bool was_async) 225b6e16652SDavid Howells { 226b6e16652SDavid Howells struct fscache_write_request *wreq = priv; 227b6e16652SDavid Howells 228b6e16652SDavid Howells fscache_clear_page_bits(fscache_cres_cookie(&wreq->cache_resources), 229b6e16652SDavid Howells wreq->mapping, wreq->start, wreq->len, 230b6e16652SDavid Howells wreq->set_bits); 231b6e16652SDavid Howells 232b6e16652SDavid Howells if (wreq->term_func) 233b6e16652SDavid Howells wreq->term_func(wreq->term_func_priv, transferred_or_error, 234b6e16652SDavid Howells was_async); 235b6e16652SDavid Howells fscache_end_operation(&wreq->cache_resources); 236b6e16652SDavid Howells kfree(wreq); 237b6e16652SDavid Howells } 238b6e16652SDavid Howells 239b6e16652SDavid Howells void __fscache_write_to_cache(struct fscache_cookie *cookie, 240b6e16652SDavid Howells struct address_space *mapping, 241b6e16652SDavid Howells loff_t start, size_t len, loff_t i_size, 242b6e16652SDavid Howells netfs_io_terminated_t term_func, 243b6e16652SDavid Howells void *term_func_priv, 244b6e16652SDavid Howells bool cond) 245b6e16652SDavid Howells { 246b6e16652SDavid Howells struct fscache_write_request *wreq; 247b6e16652SDavid Howells struct netfs_cache_resources *cres; 248b6e16652SDavid Howells struct iov_iter iter; 249b6e16652SDavid Howells int ret = -ENOBUFS; 250b6e16652SDavid Howells 251b6e16652SDavid Howells if (len == 0) 252b6e16652SDavid Howells goto abandon; 253b6e16652SDavid Howells 254b6e16652SDavid Howells _enter("%llx,%zx", start, len); 255b6e16652SDavid Howells 256b6e16652SDavid Howells wreq = kzalloc(sizeof(struct fscache_write_request), GFP_NOFS); 257b6e16652SDavid Howells if (!wreq) 258b6e16652SDavid Howells goto abandon; 259b6e16652SDavid Howells wreq->mapping = mapping; 260b6e16652SDavid Howells wreq->start = start; 261b6e16652SDavid Howells wreq->len = len; 262b6e16652SDavid Howells wreq->set_bits = cond; 263b6e16652SDavid Howells wreq->term_func = term_func; 264b6e16652SDavid Howells wreq->term_func_priv = term_func_priv; 265b6e16652SDavid Howells 266b6e16652SDavid Howells cres = &wreq->cache_resources; 267b6e16652SDavid Howells if (fscache_begin_operation(cres, cookie, FSCACHE_WANT_WRITE, 268b6e16652SDavid Howells fscache_access_io_write) < 0) 269b6e16652SDavid Howells goto abandon_free; 270b6e16652SDavid Howells 271b6e16652SDavid Howells ret = cres->ops->prepare_write(cres, &start, &len, i_size, false); 272b6e16652SDavid Howells if (ret < 0) 273b6e16652SDavid Howells goto abandon_end; 274b6e16652SDavid Howells 275b6e16652SDavid Howells /* TODO: Consider clearing page bits now for space the write isn't 276b6e16652SDavid Howells * covering. This is more complicated than it appears when THPs are 277b6e16652SDavid Howells * taken into account. 278b6e16652SDavid Howells */ 279b6e16652SDavid Howells 280b6e16652SDavid Howells iov_iter_xarray(&iter, WRITE, &mapping->i_pages, start, len); 281b6e16652SDavid Howells fscache_write(cres, start, &iter, fscache_wreq_done, wreq); 282b6e16652SDavid Howells return; 283b6e16652SDavid Howells 284b6e16652SDavid Howells abandon_end: 285b6e16652SDavid Howells return fscache_wreq_done(wreq, ret, false); 286b6e16652SDavid Howells abandon_free: 287b6e16652SDavid Howells kfree(wreq); 288b6e16652SDavid Howells abandon: 289b6e16652SDavid Howells fscache_clear_page_bits(cookie, mapping, start, len, cond); 290b6e16652SDavid Howells if (term_func) 291b6e16652SDavid Howells term_func(term_func_priv, ret, false); 292b6e16652SDavid Howells } 293b6e16652SDavid Howells EXPORT_SYMBOL(__fscache_write_to_cache); 294