Matthew Wilcox | d475c63 | 2015-02-16 15:58:56 -0800 | [diff] [blame] | 1 | /* |
| 2 | * fs/dax.c - Direct Access filesystem code |
| 3 | * Copyright (c) 2013-2014 Intel Corporation |
| 4 | * Author: Matthew Wilcox <matthew.r.wilcox@intel.com> |
| 5 | * Author: Ross Zwisler <ross.zwisler@linux.intel.com> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify it |
| 8 | * under the terms and conditions of the GNU General Public License, |
| 9 | * version 2, as published by the Free Software Foundation. |
| 10 | * |
| 11 | * This program is distributed in the hope it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 14 | * more details. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/atomic.h> |
| 18 | #include <linux/blkdev.h> |
| 19 | #include <linux/buffer_head.h> |
Ross Zwisler | d77e92e | 2015-09-09 10:29:40 -0600 | [diff] [blame] | 20 | #include <linux/dax.h> |
Matthew Wilcox | d475c63 | 2015-02-16 15:58:56 -0800 | [diff] [blame] | 21 | #include <linux/fs.h> |
| 22 | #include <linux/genhd.h> |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 23 | #include <linux/highmem.h> |
| 24 | #include <linux/memcontrol.h> |
| 25 | #include <linux/mm.h> |
Matthew Wilcox | d475c63 | 2015-02-16 15:58:56 -0800 | [diff] [blame] | 26 | #include <linux/mutex.h> |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 27 | #include <linux/pagevec.h> |
Matthew Wilcox | 289c6ae | 2015-02-16 15:58:59 -0800 | [diff] [blame] | 28 | #include <linux/sched.h> |
Ingo Molnar | f361bf4 | 2017-02-03 23:47:37 +0100 | [diff] [blame] | 29 | #include <linux/sched/signal.h> |
Matthew Wilcox | d475c63 | 2015-02-16 15:58:56 -0800 | [diff] [blame] | 30 | #include <linux/uio.h> |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 31 | #include <linux/vmstat.h> |
Dan Williams | 34c0fd5 | 2016-01-15 16:56:14 -0800 | [diff] [blame] | 32 | #include <linux/pfn_t.h> |
Dan Williams | 0e749e5 | 2016-01-15 16:55:53 -0800 | [diff] [blame] | 33 | #include <linux/sizes.h> |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 34 | #include <linux/mmu_notifier.h> |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 35 | #include <linux/iomap.h> |
| 36 | #include "internal.h" |
Matthew Wilcox | d475c63 | 2015-02-16 15:58:56 -0800 | [diff] [blame] | 37 | |
Ross Zwisler | 282a8e0 | 2017-02-22 15:39:50 -0800 | [diff] [blame] | 38 | #define CREATE_TRACE_POINTS |
| 39 | #include <trace/events/fs_dax.h> |
| 40 | |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 41 | static inline unsigned int pe_order(enum page_entry_size pe_size) |
| 42 | { |
| 43 | if (pe_size == PE_SIZE_PTE) |
| 44 | return PAGE_SHIFT - PAGE_SHIFT; |
| 45 | if (pe_size == PE_SIZE_PMD) |
| 46 | return PMD_SHIFT - PAGE_SHIFT; |
| 47 | if (pe_size == PE_SIZE_PUD) |
| 48 | return PUD_SHIFT - PAGE_SHIFT; |
| 49 | return ~0; |
| 50 | } |
| 51 | |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 52 | /* We choose 4096 entries - same as per-zone page wait tables */ |
| 53 | #define DAX_WAIT_TABLE_BITS 12 |
| 54 | #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) |
| 55 | |
Ross Zwisler | 917f345 | 2017-09-06 16:18:58 -0700 | [diff] [blame] | 56 | /* The 'colour' (ie low bits) within a PMD of a page offset. */ |
| 57 | #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) |
Matthew Wilcox | 977fbdc | 2018-01-31 16:17:36 -0800 | [diff] [blame] | 58 | #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) |
Ross Zwisler | 917f345 | 2017-09-06 16:18:58 -0700 | [diff] [blame] | 59 | |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 60 | /* The order of a PMD entry */ |
| 61 | #define PMD_ORDER (PMD_SHIFT - PAGE_SHIFT) |
| 62 | |
Ross Zwisler | ce95ab0f | 2016-11-08 11:31:44 +1100 | [diff] [blame] | 63 | static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 64 | |
| 65 | static int __init init_dax_wait_table(void) |
| 66 | { |
| 67 | int i; |
| 68 | |
| 69 | for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) |
| 70 | init_waitqueue_head(wait_table + i); |
| 71 | return 0; |
| 72 | } |
| 73 | fs_initcall(init_dax_wait_table); |
| 74 | |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 75 | /* |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 76 | * DAX pagecache entries use XArray value entries so they can't be mistaken |
| 77 | * for pages. We use one bit for locking, one bit for the entry size (PMD) |
| 78 | * and two more to tell us if the entry is a zero page or an empty entry that |
| 79 | * is just used for locking. In total four special bits. |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 80 | * |
| 81 | * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE |
| 82 | * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem |
| 83 | * block allocation. |
| 84 | */ |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 85 | #define DAX_SHIFT (4) |
| 86 | #define DAX_LOCKED (1UL << 0) |
| 87 | #define DAX_PMD (1UL << 1) |
| 88 | #define DAX_ZERO_PAGE (1UL << 2) |
| 89 | #define DAX_EMPTY (1UL << 3) |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 90 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 91 | static unsigned long dax_to_pfn(void *entry) |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 92 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 93 | return xa_to_value(entry) >> DAX_SHIFT; |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 94 | } |
| 95 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 96 | static void *dax_make_locked(unsigned long pfn, unsigned long flags) |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 97 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 98 | return xa_mk_value(flags | ((unsigned long)pfn << DAX_SHIFT) | |
| 99 | DAX_LOCKED); |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 100 | } |
| 101 | |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 102 | static void *dax_make_entry(pfn_t pfn, unsigned long flags) |
| 103 | { |
| 104 | return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT)); |
| 105 | } |
| 106 | |
| 107 | static void *dax_make_page_entry(struct page *page) |
| 108 | { |
| 109 | pfn_t pfn = page_to_pfn_t(page); |
| 110 | return dax_make_entry(pfn, PageHead(page) ? DAX_PMD : 0); |
| 111 | } |
| 112 | |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 113 | static bool dax_is_locked(void *entry) |
| 114 | { |
| 115 | return xa_to_value(entry) & DAX_LOCKED; |
| 116 | } |
| 117 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 118 | static unsigned int dax_entry_order(void *entry) |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 119 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 120 | if (xa_to_value(entry) & DAX_PMD) |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 121 | return PMD_ORDER; |
Ross Zwisler | 527b19d | 2017-09-06 16:18:51 -0700 | [diff] [blame] | 122 | return 0; |
| 123 | } |
| 124 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 125 | static int dax_is_pmd_entry(void *entry) |
| 126 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 127 | return xa_to_value(entry) & DAX_PMD; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 128 | } |
| 129 | |
| 130 | static int dax_is_pte_entry(void *entry) |
| 131 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 132 | return !(xa_to_value(entry) & DAX_PMD); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 133 | } |
| 134 | |
| 135 | static int dax_is_zero_entry(void *entry) |
| 136 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 137 | return xa_to_value(entry) & DAX_ZERO_PAGE; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 138 | } |
| 139 | |
| 140 | static int dax_is_empty_entry(void *entry) |
| 141 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 142 | return xa_to_value(entry) & DAX_EMPTY; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 143 | } |
| 144 | |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 145 | /* |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 146 | * DAX page cache entry locking |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 147 | */ |
| 148 | struct exceptional_entry_key { |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 149 | struct xarray *xa; |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 150 | pgoff_t entry_start; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 151 | }; |
| 152 | |
| 153 | struct wait_exceptional_entry_queue { |
Ingo Molnar | ac6424b | 2017-06-20 12:06:13 +0200 | [diff] [blame] | 154 | wait_queue_entry_t wait; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 155 | struct exceptional_entry_key key; |
| 156 | }; |
| 157 | |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 158 | static wait_queue_head_t *dax_entry_waitqueue(struct xarray *xa, |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 159 | pgoff_t index, void *entry, struct exceptional_entry_key *key) |
| 160 | { |
| 161 | unsigned long hash; |
| 162 | |
| 163 | /* |
| 164 | * If 'entry' is a PMD, align the 'index' that we use for the wait |
| 165 | * queue to the start of that PMD. This ensures that all offsets in |
| 166 | * the range covered by the PMD map to the same bit lock. |
| 167 | */ |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 168 | if (dax_is_pmd_entry(entry)) |
Ross Zwisler | 917f345 | 2017-09-06 16:18:58 -0700 | [diff] [blame] | 169 | index &= ~PG_PMD_COLOUR; |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 170 | |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 171 | key->xa = xa; |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 172 | key->entry_start = index; |
| 173 | |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 174 | hash = hash_long((unsigned long)xa ^ index, DAX_WAIT_TABLE_BITS); |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 175 | return wait_table + hash; |
| 176 | } |
| 177 | |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 178 | static int wake_exceptional_entry_func(wait_queue_entry_t *wait, |
| 179 | unsigned int mode, int sync, void *keyp) |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 180 | { |
| 181 | struct exceptional_entry_key *key = keyp; |
| 182 | struct wait_exceptional_entry_queue *ewait = |
| 183 | container_of(wait, struct wait_exceptional_entry_queue, wait); |
| 184 | |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 185 | if (key->xa != ewait->key.xa || |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 186 | key->entry_start != ewait->key.entry_start) |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 187 | return 0; |
| 188 | return autoremove_wake_function(wait, mode, sync, NULL); |
| 189 | } |
| 190 | |
| 191 | /* |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 192 | * @entry may no longer be the entry at the index in the mapping. |
| 193 | * The important information it's conveying is whether the entry at |
| 194 | * this index used to be a PMD entry. |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 195 | */ |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 196 | static void dax_wake_mapping_entry_waiter(struct xarray *xa, |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 197 | pgoff_t index, void *entry, bool wake_all) |
| 198 | { |
| 199 | struct exceptional_entry_key key; |
| 200 | wait_queue_head_t *wq; |
| 201 | |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 202 | wq = dax_entry_waitqueue(xa, index, entry, &key); |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 203 | |
| 204 | /* |
| 205 | * Checking for locked entry and prepare_to_wait_exclusive() happens |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 206 | * under the i_pages lock, ditto for entry handling in our callers. |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 207 | * So at this point all tasks that could have seen our entry locked |
| 208 | * must be in the waitqueue and the following check will see them. |
| 209 | */ |
| 210 | if (waitqueue_active(wq)) |
| 211 | __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); |
| 212 | } |
| 213 | |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 214 | static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all) |
| 215 | { |
| 216 | return dax_wake_mapping_entry_waiter(xas->xa, xas->xa_index, entry, |
| 217 | wake_all); |
| 218 | } |
| 219 | |
| 220 | /* |
| 221 | * Look up entry in page cache, wait for it to become unlocked if it |
| 222 | * is a DAX entry and return it. The caller must subsequently call |
| 223 | * put_unlocked_entry() if it did not lock the entry or dax_unlock_entry() |
| 224 | * if it did. |
| 225 | * |
| 226 | * Must be called with the i_pages lock held. |
| 227 | */ |
| 228 | static void *get_unlocked_entry(struct xa_state *xas) |
| 229 | { |
| 230 | void *entry; |
| 231 | struct wait_exceptional_entry_queue ewait; |
| 232 | wait_queue_head_t *wq; |
| 233 | |
| 234 | init_wait(&ewait.wait); |
| 235 | ewait.wait.func = wake_exceptional_entry_func; |
| 236 | |
| 237 | for (;;) { |
| 238 | entry = xas_load(xas); |
| 239 | if (!entry || xa_is_internal(entry) || |
| 240 | WARN_ON_ONCE(!xa_is_value(entry)) || |
| 241 | !dax_is_locked(entry)) |
| 242 | return entry; |
| 243 | |
| 244 | wq = dax_entry_waitqueue(xas->xa, xas->xa_index, entry, |
| 245 | &ewait.key); |
| 246 | prepare_to_wait_exclusive(wq, &ewait.wait, |
| 247 | TASK_UNINTERRUPTIBLE); |
| 248 | xas_unlock_irq(xas); |
| 249 | xas_reset(xas); |
| 250 | schedule(); |
| 251 | finish_wait(wq, &ewait.wait); |
| 252 | xas_lock_irq(xas); |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | static void put_unlocked_entry(struct xa_state *xas, void *entry) |
| 257 | { |
| 258 | /* If we were the only waiter woken, wake the next one */ |
| 259 | if (entry) |
| 260 | dax_wake_entry(xas, entry, false); |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * We used the xa_state to get the entry, but then we locked the entry and |
| 265 | * dropped the xa_lock, so we know the xa_state is stale and must be reset |
| 266 | * before use. |
| 267 | */ |
| 268 | static void dax_unlock_entry(struct xa_state *xas, void *entry) |
| 269 | { |
| 270 | void *old; |
| 271 | |
| 272 | xas_reset(xas); |
| 273 | xas_lock_irq(xas); |
| 274 | old = xas_store(xas, entry); |
| 275 | xas_unlock_irq(xas); |
| 276 | BUG_ON(!dax_is_locked(old)); |
| 277 | dax_wake_entry(xas, entry, false); |
| 278 | } |
| 279 | |
| 280 | /* |
| 281 | * Return: The entry stored at this location before it was locked. |
| 282 | */ |
| 283 | static void *dax_lock_entry(struct xa_state *xas, void *entry) |
| 284 | { |
| 285 | unsigned long v = xa_to_value(entry); |
| 286 | return xas_store(xas, xa_mk_value(v | DAX_LOCKED)); |
| 287 | } |
| 288 | |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 289 | /* |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 290 | * Check whether the given slot is locked. Must be called with the i_pages |
| 291 | * lock held. |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 292 | */ |
| 293 | static inline int slot_locked(struct address_space *mapping, void **slot) |
| 294 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 295 | unsigned long entry = xa_to_value( |
| 296 | radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock)); |
| 297 | return entry & DAX_LOCKED; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 298 | } |
| 299 | |
| 300 | /* |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 301 | * Mark the given slot as locked. Must be called with the i_pages lock held. |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 302 | */ |
| 303 | static inline void *lock_slot(struct address_space *mapping, void **slot) |
| 304 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 305 | unsigned long v = xa_to_value( |
| 306 | radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock)); |
| 307 | void *entry = xa_mk_value(v | DAX_LOCKED); |
| 308 | radix_tree_replace_slot(&mapping->i_pages, slot, entry); |
| 309 | return entry; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 310 | } |
| 311 | |
| 312 | /* |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 313 | * Mark the given slot as unlocked. Must be called with the i_pages lock held. |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 314 | */ |
| 315 | static inline void *unlock_slot(struct address_space *mapping, void **slot) |
| 316 | { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 317 | unsigned long v = xa_to_value( |
| 318 | radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock)); |
| 319 | void *entry = xa_mk_value(v & ~DAX_LOCKED); |
| 320 | radix_tree_replace_slot(&mapping->i_pages, slot, entry); |
| 321 | return entry; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 322 | } |
| 323 | |
| 324 | /* |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 325 | * Lookup entry in page cache, wait for it to become unlocked if it is |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 326 | * a DAX entry and return it. The caller must call |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 327 | * put_unlocked_mapping_entry() when he decided not to lock the entry or |
| 328 | * put_locked_mapping_entry() when he locked the entry and now wants to |
| 329 | * unlock it. |
| 330 | * |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 331 | * Must be called with the i_pages lock held. |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 332 | */ |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 333 | static void *__get_unlocked_mapping_entry(struct address_space *mapping, |
| 334 | pgoff_t index, void ***slotp, bool (*wait_fn)(void)) |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 335 | { |
Ross Zwisler | e3ad61c | 2016-11-08 11:32:12 +1100 | [diff] [blame] | 336 | void *entry, **slot; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 337 | struct wait_exceptional_entry_queue ewait; |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 338 | wait_queue_head_t *wq; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 339 | |
| 340 | init_wait(&ewait.wait); |
| 341 | ewait.wait.func = wake_exceptional_entry_func; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 342 | |
| 343 | for (;;) { |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 344 | bool revalidate; |
| 345 | |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 346 | entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 347 | &slot); |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 348 | if (!entry || |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 349 | WARN_ON_ONCE(!xa_is_value(entry)) || |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 350 | !slot_locked(mapping, slot)) { |
| 351 | if (slotp) |
| 352 | *slotp = slot; |
Ross Zwisler | e3ad61c | 2016-11-08 11:32:12 +1100 | [diff] [blame] | 353 | return entry; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 354 | } |
Ross Zwisler | 63e95b5 | 2016-11-08 11:32:20 +1100 | [diff] [blame] | 355 | |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 356 | wq = dax_entry_waitqueue(&mapping->i_pages, index, entry, |
| 357 | &ewait.key); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 358 | prepare_to_wait_exclusive(wq, &ewait.wait, |
| 359 | TASK_UNINTERRUPTIBLE); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 360 | xa_unlock_irq(&mapping->i_pages); |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 361 | revalidate = wait_fn(); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 362 | finish_wait(wq, &ewait.wait); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 363 | xa_lock_irq(&mapping->i_pages); |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 364 | if (revalidate) |
| 365 | return ERR_PTR(-EAGAIN); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 366 | } |
| 367 | } |
| 368 | |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 369 | static bool entry_wait(void) |
| 370 | { |
| 371 | schedule(); |
| 372 | /* |
| 373 | * Never return an ERR_PTR() from |
| 374 | * __get_unlocked_mapping_entry(), just keep looping. |
| 375 | */ |
| 376 | return false; |
| 377 | } |
| 378 | |
| 379 | static void *get_unlocked_mapping_entry(struct address_space *mapping, |
| 380 | pgoff_t index, void ***slotp) |
| 381 | { |
| 382 | return __get_unlocked_mapping_entry(mapping, index, slotp, entry_wait); |
| 383 | } |
| 384 | |
| 385 | static void unlock_mapping_entry(struct address_space *mapping, pgoff_t index) |
Jan Kara | b1aa812 | 2016-12-14 15:07:24 -0800 | [diff] [blame] | 386 | { |
| 387 | void *entry, **slot; |
| 388 | |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 389 | xa_lock_irq(&mapping->i_pages); |
| 390 | entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, &slot); |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 391 | if (WARN_ON_ONCE(!entry || !xa_is_value(entry) || |
Jan Kara | b1aa812 | 2016-12-14 15:07:24 -0800 | [diff] [blame] | 392 | !slot_locked(mapping, slot))) { |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 393 | xa_unlock_irq(&mapping->i_pages); |
Jan Kara | b1aa812 | 2016-12-14 15:07:24 -0800 | [diff] [blame] | 394 | return; |
| 395 | } |
| 396 | unlock_slot(mapping, slot); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 397 | xa_unlock_irq(&mapping->i_pages); |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 398 | dax_wake_mapping_entry_waiter(&mapping->i_pages, index, entry, false); |
Jan Kara | b1aa812 | 2016-12-14 15:07:24 -0800 | [diff] [blame] | 399 | } |
| 400 | |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 401 | static void put_locked_mapping_entry(struct address_space *mapping, |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 402 | pgoff_t index) |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 403 | { |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 404 | unlock_mapping_entry(mapping, index); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 405 | } |
| 406 | |
| 407 | /* |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 408 | * Called when we are done with page cache entry we looked up via |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 409 | * get_unlocked_mapping_entry() and which we didn't lock in the end. |
| 410 | */ |
| 411 | static void put_unlocked_mapping_entry(struct address_space *mapping, |
| 412 | pgoff_t index, void *entry) |
| 413 | { |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 414 | if (!entry) |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 415 | return; |
| 416 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 417 | /* We have to wake up next waiter for the page cache entry lock */ |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 418 | dax_wake_mapping_entry_waiter(&mapping->i_pages, index, entry, false); |
Ross Zwisler | 422476c | 2016-11-08 11:33:44 +1100 | [diff] [blame] | 419 | } |
| 420 | |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 421 | static unsigned long dax_entry_size(void *entry) |
| 422 | { |
| 423 | if (dax_is_zero_entry(entry)) |
| 424 | return 0; |
| 425 | else if (dax_is_empty_entry(entry)) |
| 426 | return 0; |
| 427 | else if (dax_is_pmd_entry(entry)) |
| 428 | return PMD_SIZE; |
| 429 | else |
| 430 | return PAGE_SIZE; |
| 431 | } |
| 432 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 433 | static unsigned long dax_end_pfn(void *entry) |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 434 | { |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 435 | return dax_to_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE; |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 436 | } |
| 437 | |
| 438 | /* |
| 439 | * Iterate through all mapped pfns represented by an entry, i.e. skip |
| 440 | * 'empty' and 'zero' entries. |
| 441 | */ |
| 442 | #define for_each_mapped_pfn(entry, pfn) \ |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 443 | for (pfn = dax_to_pfn(entry); \ |
| 444 | pfn < dax_end_pfn(entry); pfn++) |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 445 | |
Dan Williams | 73449da | 2018-07-13 21:49:50 -0700 | [diff] [blame] | 446 | /* |
| 447 | * TODO: for reflink+dax we need a way to associate a single page with |
| 448 | * multiple address_space instances at different linear_page_index() |
| 449 | * offsets. |
| 450 | */ |
| 451 | static void dax_associate_entry(void *entry, struct address_space *mapping, |
| 452 | struct vm_area_struct *vma, unsigned long address) |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 453 | { |
Dan Williams | 73449da | 2018-07-13 21:49:50 -0700 | [diff] [blame] | 454 | unsigned long size = dax_entry_size(entry), pfn, index; |
| 455 | int i = 0; |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 456 | |
| 457 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) |
| 458 | return; |
| 459 | |
Dan Williams | 73449da | 2018-07-13 21:49:50 -0700 | [diff] [blame] | 460 | index = linear_page_index(vma, address & ~(size - 1)); |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 461 | for_each_mapped_pfn(entry, pfn) { |
| 462 | struct page *page = pfn_to_page(pfn); |
| 463 | |
| 464 | WARN_ON_ONCE(page->mapping); |
| 465 | page->mapping = mapping; |
Dan Williams | 73449da | 2018-07-13 21:49:50 -0700 | [diff] [blame] | 466 | page->index = index + i++; |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 467 | } |
| 468 | } |
| 469 | |
| 470 | static void dax_disassociate_entry(void *entry, struct address_space *mapping, |
| 471 | bool trunc) |
| 472 | { |
| 473 | unsigned long pfn; |
| 474 | |
| 475 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) |
| 476 | return; |
| 477 | |
| 478 | for_each_mapped_pfn(entry, pfn) { |
| 479 | struct page *page = pfn_to_page(pfn); |
| 480 | |
| 481 | WARN_ON_ONCE(trunc && page_ref_count(page) > 1); |
| 482 | WARN_ON_ONCE(page->mapping && page->mapping != mapping); |
| 483 | page->mapping = NULL; |
Dan Williams | 73449da | 2018-07-13 21:49:50 -0700 | [diff] [blame] | 484 | page->index = 0; |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 485 | } |
| 486 | } |
| 487 | |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 488 | static struct page *dax_busy_page(void *entry) |
| 489 | { |
| 490 | unsigned long pfn; |
| 491 | |
| 492 | for_each_mapped_pfn(entry, pfn) { |
| 493 | struct page *page = pfn_to_page(pfn); |
| 494 | |
| 495 | if (page_ref_count(page) > 1) |
| 496 | return page; |
| 497 | } |
| 498 | return NULL; |
| 499 | } |
| 500 | |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 501 | bool dax_lock_mapping_entry(struct page *page) |
| 502 | { |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 503 | XA_STATE(xas, NULL, 0); |
| 504 | void *entry; |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 505 | |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 506 | for (;;) { |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 507 | struct address_space *mapping = READ_ONCE(page->mapping); |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 508 | |
| 509 | if (!dax_mapping(mapping)) |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 510 | return false; |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 511 | |
| 512 | /* |
| 513 | * In the device-dax case there's no need to lock, a |
| 514 | * struct dev_pagemap pin is sufficient to keep the |
| 515 | * inode alive, and we assume we have dev_pagemap pin |
| 516 | * otherwise we would not have a valid pfn_to_page() |
| 517 | * translation. |
| 518 | */ |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 519 | if (S_ISCHR(mapping->host->i_mode)) |
| 520 | return true; |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 521 | |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 522 | xas.xa = &mapping->i_pages; |
| 523 | xas_lock_irq(&xas); |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 524 | if (mapping != page->mapping) { |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 525 | xas_unlock_irq(&xas); |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 526 | continue; |
| 527 | } |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 528 | xas_set(&xas, page->index); |
| 529 | entry = xas_load(&xas); |
| 530 | if (dax_is_locked(entry)) { |
| 531 | entry = get_unlocked_entry(&xas); |
| 532 | /* Did the page move while we slept? */ |
| 533 | if (dax_to_pfn(entry) != page_to_pfn(page)) { |
| 534 | xas_unlock_irq(&xas); |
| 535 | continue; |
| 536 | } |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 537 | } |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 538 | dax_lock_entry(&xas, entry); |
| 539 | xas_unlock_irq(&xas); |
| 540 | return true; |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 541 | } |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 542 | } |
| 543 | |
| 544 | void dax_unlock_mapping_entry(struct page *page) |
| 545 | { |
| 546 | struct address_space *mapping = page->mapping; |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 547 | XA_STATE(xas, &mapping->i_pages, page->index); |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 548 | |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 549 | if (S_ISCHR(mapping->host->i_mode)) |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 550 | return; |
| 551 | |
Matthew Wilcox | 9f32d22 | 2018-06-12 09:46:30 -0400 | [diff] [blame^] | 552 | dax_unlock_entry(&xas, dax_make_page_entry(page)); |
Dan Williams | c2a7d2a | 2018-07-13 21:50:16 -0700 | [diff] [blame] | 553 | } |
| 554 | |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 555 | /* |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 556 | * Find page cache entry at given index. If it is a DAX entry, return it |
| 557 | * with the entry locked. If the page cache doesn't contain an entry at |
| 558 | * that index, add a locked empty entry. |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 559 | * |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 560 | * When requesting an entry with size DAX_PMD, grab_mapping_entry() will |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 561 | * either return that locked entry or will return an error. This error will |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 562 | * happen if there are any 4k entries within the 2MiB range that we are |
| 563 | * requesting. |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 564 | * |
| 565 | * We always favor 4k entries over 2MiB entries. There isn't a flow where we |
| 566 | * evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB |
| 567 | * insertion will fail if it finds any 4k entries already in the tree, and a |
| 568 | * 4k insertion will cause an existing 2MiB entry to be unmapped and |
| 569 | * downgraded to 4k entries. This happens for both 2MiB huge zero pages as |
| 570 | * well as 2MiB empty entries. |
| 571 | * |
| 572 | * The exception to this downgrade path is for 2MiB DAX PMD entries that have |
| 573 | * real storage backing them. We will leave these real 2MiB DAX entries in |
| 574 | * the tree, and PTE writes will simply dirty the entire 2MiB DAX entry. |
| 575 | * |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 576 | * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For |
| 577 | * persistent memory the benefit is doubtful. We can add that later if we can |
| 578 | * show it helps. |
| 579 | */ |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 580 | static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, |
| 581 | unsigned long size_flag) |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 582 | { |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 583 | bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */ |
Ross Zwisler | e3ad61c | 2016-11-08 11:32:12 +1100 | [diff] [blame] | 584 | void *entry, **slot; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 585 | |
| 586 | restart: |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 587 | xa_lock_irq(&mapping->i_pages); |
Ross Zwisler | e3ad61c | 2016-11-08 11:32:12 +1100 | [diff] [blame] | 588 | entry = get_unlocked_mapping_entry(mapping, index, &slot); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 589 | |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 590 | if (WARN_ON_ONCE(entry && !xa_is_value(entry))) { |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 591 | entry = ERR_PTR(-EIO); |
| 592 | goto out_unlock; |
| 593 | } |
| 594 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 595 | if (entry) { |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 596 | if (size_flag & DAX_PMD) { |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 597 | if (dax_is_pte_entry(entry)) { |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 598 | put_unlocked_mapping_entry(mapping, index, |
| 599 | entry); |
| 600 | entry = ERR_PTR(-EEXIST); |
| 601 | goto out_unlock; |
| 602 | } |
| 603 | } else { /* trying to grab a PTE entry */ |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 604 | if (dax_is_pmd_entry(entry) && |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 605 | (dax_is_zero_entry(entry) || |
| 606 | dax_is_empty_entry(entry))) { |
| 607 | pmd_downgrade = true; |
| 608 | } |
| 609 | } |
| 610 | } |
| 611 | |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 612 | /* No entry for given index? Make sure radix tree is big enough. */ |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 613 | if (!entry || pmd_downgrade) { |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 614 | int err; |
| 615 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 616 | if (pmd_downgrade) { |
| 617 | /* |
| 618 | * Make sure 'entry' remains valid while we drop |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 619 | * the i_pages lock. |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 620 | */ |
| 621 | entry = lock_slot(mapping, slot); |
| 622 | } |
| 623 | |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 624 | xa_unlock_irq(&mapping->i_pages); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 625 | /* |
| 626 | * Besides huge zero pages the only other thing that gets |
| 627 | * downgraded are empty entries which don't need to be |
| 628 | * unmapped. |
| 629 | */ |
| 630 | if (pmd_downgrade && dax_is_zero_entry(entry)) |
Matthew Wilcox | 977fbdc | 2018-01-31 16:17:36 -0800 | [diff] [blame] | 631 | unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, |
| 632 | PG_PMD_NR, false); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 633 | |
Jan Kara | 0cb80b4 | 2016-12-12 21:34:12 -0500 | [diff] [blame] | 634 | err = radix_tree_preload( |
| 635 | mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); |
| 636 | if (err) { |
| 637 | if (pmd_downgrade) |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 638 | put_locked_mapping_entry(mapping, index); |
Jan Kara | 0cb80b4 | 2016-12-12 21:34:12 -0500 | [diff] [blame] | 639 | return ERR_PTR(err); |
| 640 | } |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 641 | xa_lock_irq(&mapping->i_pages); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 642 | |
Ross Zwisler | e11f8b7 | 2017-04-07 16:04:57 -0700 | [diff] [blame] | 643 | if (!entry) { |
| 644 | /* |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 645 | * We needed to drop the i_pages lock while calling |
Ross Zwisler | e11f8b7 | 2017-04-07 16:04:57 -0700 | [diff] [blame] | 646 | * radix_tree_preload() and we didn't have an entry to |
| 647 | * lock. See if another thread inserted an entry at |
| 648 | * our index during this time. |
| 649 | */ |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 650 | entry = __radix_tree_lookup(&mapping->i_pages, index, |
Ross Zwisler | e11f8b7 | 2017-04-07 16:04:57 -0700 | [diff] [blame] | 651 | NULL, &slot); |
| 652 | if (entry) { |
| 653 | radix_tree_preload_end(); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 654 | xa_unlock_irq(&mapping->i_pages); |
Ross Zwisler | e11f8b7 | 2017-04-07 16:04:57 -0700 | [diff] [blame] | 655 | goto restart; |
| 656 | } |
| 657 | } |
| 658 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 659 | if (pmd_downgrade) { |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 660 | dax_disassociate_entry(entry, mapping, false); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 661 | radix_tree_delete(&mapping->i_pages, index); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 662 | mapping->nrexceptional--; |
Matthew Wilcox | ec4907f | 2018-03-28 11:01:43 -0400 | [diff] [blame] | 663 | dax_wake_mapping_entry_waiter(&mapping->i_pages, |
| 664 | index, entry, true); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 665 | } |
| 666 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 667 | entry = dax_make_locked(0, size_flag | DAX_EMPTY); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 668 | |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 669 | err = __radix_tree_insert(&mapping->i_pages, index, |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 670 | dax_entry_order(entry), entry); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 671 | radix_tree_preload_end(); |
| 672 | if (err) { |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 673 | xa_unlock_irq(&mapping->i_pages); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 674 | /* |
Ross Zwisler | e11f8b7 | 2017-04-07 16:04:57 -0700 | [diff] [blame] | 675 | * Our insertion of a DAX entry failed, most likely |
| 676 | * because we were inserting a PMD entry and it |
| 677 | * collided with a PTE sized entry at a different |
| 678 | * index in the PMD range. We haven't inserted |
| 679 | * anything into the radix tree and have no waiters to |
| 680 | * wake. |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 681 | */ |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 682 | return ERR_PTR(err); |
| 683 | } |
| 684 | /* Good, we have inserted empty locked entry into the tree. */ |
| 685 | mapping->nrexceptional++; |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 686 | xa_unlock_irq(&mapping->i_pages); |
Ross Zwisler | e3ad61c | 2016-11-08 11:32:12 +1100 | [diff] [blame] | 687 | return entry; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 688 | } |
Ross Zwisler | e3ad61c | 2016-11-08 11:32:12 +1100 | [diff] [blame] | 689 | entry = lock_slot(mapping, slot); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 690 | out_unlock: |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 691 | xa_unlock_irq(&mapping->i_pages); |
Ross Zwisler | e3ad61c | 2016-11-08 11:32:12 +1100 | [diff] [blame] | 692 | return entry; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 693 | } |
| 694 | |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 695 | /** |
| 696 | * dax_layout_busy_page - find first pinned page in @mapping |
| 697 | * @mapping: address space to scan for a page with ref count > 1 |
| 698 | * |
| 699 | * DAX requires ZONE_DEVICE mapped pages. These pages are never |
| 700 | * 'onlined' to the page allocator so they are considered idle when |
| 701 | * page->count == 1. A filesystem uses this interface to determine if |
| 702 | * any page in the mapping is busy, i.e. for DMA, or other |
| 703 | * get_user_pages() usages. |
| 704 | * |
| 705 | * It is expected that the filesystem is holding locks to block the |
| 706 | * establishment of new mappings in this address_space. I.e. it expects |
| 707 | * to be able to run unmap_mapping_range() and subsequently not race |
| 708 | * mapping_mapped() becoming true. |
| 709 | */ |
| 710 | struct page *dax_layout_busy_page(struct address_space *mapping) |
| 711 | { |
Matthew Wilcox | 084a899 | 2018-05-17 13:03:48 -0400 | [diff] [blame] | 712 | XA_STATE(xas, &mapping->i_pages, 0); |
| 713 | void *entry; |
| 714 | unsigned int scanned = 0; |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 715 | struct page *page = NULL; |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 716 | |
| 717 | /* |
| 718 | * In the 'limited' case get_user_pages() for dax is disabled. |
| 719 | */ |
| 720 | if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) |
| 721 | return NULL; |
| 722 | |
| 723 | if (!dax_mapping(mapping) || !mapping_mapped(mapping)) |
| 724 | return NULL; |
| 725 | |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 726 | /* |
| 727 | * If we race get_user_pages_fast() here either we'll see the |
Matthew Wilcox | 084a899 | 2018-05-17 13:03:48 -0400 | [diff] [blame] | 728 | * elevated page count in the iteration and wait, or |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 729 | * get_user_pages_fast() will see that the page it took a reference |
| 730 | * against is no longer mapped in the page tables and bail to the |
| 731 | * get_user_pages() slow path. The slow path is protected by |
| 732 | * pte_lock() and pmd_lock(). New references are not taken without |
| 733 | * holding those locks, and unmap_mapping_range() will not zero the |
| 734 | * pte or pmd without holding the respective lock, so we are |
| 735 | * guaranteed to either see new references or prevent new |
| 736 | * references from being established. |
| 737 | */ |
| 738 | unmap_mapping_range(mapping, 0, 0, 1); |
| 739 | |
Matthew Wilcox | 084a899 | 2018-05-17 13:03:48 -0400 | [diff] [blame] | 740 | xas_lock_irq(&xas); |
| 741 | xas_for_each(&xas, entry, ULONG_MAX) { |
| 742 | if (WARN_ON_ONCE(!xa_is_value(entry))) |
| 743 | continue; |
| 744 | if (unlikely(dax_is_locked(entry))) |
| 745 | entry = get_unlocked_entry(&xas); |
| 746 | if (entry) |
| 747 | page = dax_busy_page(entry); |
| 748 | put_unlocked_entry(&xas, entry); |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 749 | if (page) |
| 750 | break; |
Matthew Wilcox | 084a899 | 2018-05-17 13:03:48 -0400 | [diff] [blame] | 751 | if (++scanned % XA_CHECK_SCHED) |
| 752 | continue; |
| 753 | |
| 754 | xas_pause(&xas); |
| 755 | xas_unlock_irq(&xas); |
| 756 | cond_resched(); |
| 757 | xas_lock_irq(&xas); |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 758 | } |
Matthew Wilcox | 084a899 | 2018-05-17 13:03:48 -0400 | [diff] [blame] | 759 | xas_unlock_irq(&xas); |
Dan Williams | 5fac740 | 2018-03-09 17:44:31 -0800 | [diff] [blame] | 760 | return page; |
| 761 | } |
| 762 | EXPORT_SYMBOL_GPL(dax_layout_busy_page); |
| 763 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 764 | static int __dax_invalidate_entry(struct address_space *mapping, |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 765 | pgoff_t index, bool trunc) |
| 766 | { |
Matthew Wilcox | 07f2d89 | 2018-03-28 15:40:41 -0400 | [diff] [blame] | 767 | XA_STATE(xas, &mapping->i_pages, index); |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 768 | int ret = 0; |
| 769 | void *entry; |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 770 | |
Matthew Wilcox | 07f2d89 | 2018-03-28 15:40:41 -0400 | [diff] [blame] | 771 | xas_lock_irq(&xas); |
| 772 | entry = get_unlocked_entry(&xas); |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 773 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 774 | goto out; |
| 775 | if (!trunc && |
Matthew Wilcox | 07f2d89 | 2018-03-28 15:40:41 -0400 | [diff] [blame] | 776 | (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) || |
| 777 | xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE))) |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 778 | goto out; |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 779 | dax_disassociate_entry(entry, mapping, trunc); |
Matthew Wilcox | 07f2d89 | 2018-03-28 15:40:41 -0400 | [diff] [blame] | 780 | xas_store(&xas, NULL); |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 781 | mapping->nrexceptional--; |
| 782 | ret = 1; |
| 783 | out: |
Matthew Wilcox | 07f2d89 | 2018-03-28 15:40:41 -0400 | [diff] [blame] | 784 | put_unlocked_entry(&xas, entry); |
| 785 | xas_unlock_irq(&xas); |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 786 | return ret; |
| 787 | } |
Matthew Wilcox | 07f2d89 | 2018-03-28 15:40:41 -0400 | [diff] [blame] | 788 | |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 789 | /* |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 790 | * Delete DAX entry at @index from @mapping. Wait for it |
| 791 | * to be unlocked before deleting it. |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 792 | */ |
| 793 | int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) |
| 794 | { |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 795 | int ret = __dax_invalidate_entry(mapping, index, true); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 796 | |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 797 | /* |
| 798 | * This gets called from truncate / punch_hole path. As such, the caller |
| 799 | * must hold locks protecting against concurrent modifications of the |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 800 | * page cache (usually fs-private i_mmap_sem for writing). Since the |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 801 | * caller has seen a DAX entry for this index, we better find it |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 802 | * at that index as well... |
| 803 | */ |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 804 | WARN_ON_ONCE(!ret); |
| 805 | return ret; |
| 806 | } |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 807 | |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 808 | /* |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 809 | * Invalidate DAX entry if it is clean. |
Jan Kara | c6dcf52 | 2016-08-10 17:22:44 +0200 | [diff] [blame] | 810 | */ |
| 811 | int dax_invalidate_mapping_entry_sync(struct address_space *mapping, |
| 812 | pgoff_t index) |
| 813 | { |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 814 | return __dax_invalidate_entry(mapping, index, false); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 815 | } |
| 816 | |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 817 | static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, |
| 818 | sector_t sector, size_t size, struct page *to, |
| 819 | unsigned long vaddr) |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 820 | { |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 821 | void *vto, *kaddr; |
| 822 | pgoff_t pgoff; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 823 | long rc; |
| 824 | int id; |
Ross Zwisler | e2e0539 | 2015-08-18 13:55:41 -0600 | [diff] [blame] | 825 | |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 826 | rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
| 827 | if (rc) |
| 828 | return rc; |
| 829 | |
| 830 | id = dax_read_lock(); |
Huaisheng Ye | 86ed913 | 2018-07-30 15:15:48 +0800 | [diff] [blame] | 831 | rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, NULL); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 832 | if (rc < 0) { |
| 833 | dax_read_unlock(id); |
| 834 | return rc; |
| 835 | } |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 836 | vto = kmap_atomic(to); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 837 | copy_user_page(vto, (void __force *)kaddr, vaddr, to); |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 838 | kunmap_atomic(vto); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 839 | dax_read_unlock(id); |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 840 | return 0; |
| 841 | } |
| 842 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 843 | /* |
| 844 | * By this point grab_mapping_entry() has ensured that we have a locked entry |
| 845 | * of the appropriate size so we don't have to worry about downgrading PMDs to |
| 846 | * PTEs. If we happen to be trying to insert a PTE and there is a PMD |
| 847 | * already in the tree, we will skip the insertion and just dirty the PMD as |
| 848 | * appropriate. |
| 849 | */ |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 850 | static void *dax_insert_entry(struct address_space *mapping, |
| 851 | struct vm_fault *vmf, |
| 852 | void *entry, pfn_t pfn_t, unsigned long flags, bool dirty) |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 853 | { |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 854 | struct radix_tree_root *pages = &mapping->i_pages; |
Dan Williams | 3fe0791 | 2017-10-14 17:13:45 -0700 | [diff] [blame] | 855 | unsigned long pfn = pfn_t_to_pfn(pfn_t); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 856 | pgoff_t index = vmf->pgoff; |
Dan Williams | 3fe0791 | 2017-10-14 17:13:45 -0700 | [diff] [blame] | 857 | void *new_entry; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 858 | |
Jan Kara | f5b7b74 | 2017-11-01 16:36:40 +0100 | [diff] [blame] | 859 | if (dirty) |
Dmitry Monakhov | d2b2a28 | 2016-02-05 15:36:55 -0800 | [diff] [blame] | 860 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 861 | |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 862 | if (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE)) { |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 863 | /* we are replacing a zero page with block mapping */ |
| 864 | if (dax_is_pmd_entry(entry)) |
Matthew Wilcox | 977fbdc | 2018-01-31 16:17:36 -0800 | [diff] [blame] | 865 | unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, |
| 866 | PG_PMD_NR, false); |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 867 | else /* pte entry */ |
Matthew Wilcox | 977fbdc | 2018-01-31 16:17:36 -0800 | [diff] [blame] | 868 | unmap_mapping_pages(mapping, vmf->pgoff, 1, false); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 869 | } |
| 870 | |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 871 | xa_lock_irq(pages); |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 872 | new_entry = dax_make_locked(pfn, flags); |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 873 | if (dax_entry_size(entry) != dax_entry_size(new_entry)) { |
| 874 | dax_disassociate_entry(entry, mapping, false); |
Dan Williams | 73449da | 2018-07-13 21:49:50 -0700 | [diff] [blame] | 875 | dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address); |
Dan Williams | d2c997c | 2017-12-22 22:02:48 -0800 | [diff] [blame] | 876 | } |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 877 | |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 878 | if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 879 | /* |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 880 | * Only swap our new entry into the page cache if the current |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 881 | * entry is a zero page or an empty entry. If a normal PTE or |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 882 | * PMD entry is already in the cache, we leave it alone. This |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 883 | * means that if we are trying to insert a PTE and the |
| 884 | * existing entry is a PMD, we will just leave the PMD in the |
| 885 | * tree and dirty it if necessary. |
| 886 | */ |
Johannes Weiner | f794243 | 2016-12-12 16:43:41 -0800 | [diff] [blame] | 887 | struct radix_tree_node *node; |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 888 | void **slot; |
| 889 | void *ret; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 890 | |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 891 | ret = __radix_tree_lookup(pages, index, &node, &slot); |
Jan Kara | ac401cc | 2016-05-12 18:29:18 +0200 | [diff] [blame] | 892 | WARN_ON_ONCE(ret != entry); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 893 | __radix_tree_replace(pages, node, slot, |
Mel Gorman | c7df8ad | 2017-11-15 17:37:41 -0800 | [diff] [blame] | 894 | new_entry, NULL); |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 895 | entry = new_entry; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 896 | } |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 897 | |
Jan Kara | f5b7b74 | 2017-11-01 16:36:40 +0100 | [diff] [blame] | 898 | if (dirty) |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 899 | radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY); |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 900 | |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 901 | xa_unlock_irq(pages); |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 902 | return entry; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 903 | } |
| 904 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 905 | static inline |
| 906 | unsigned long pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 907 | { |
| 908 | unsigned long address; |
| 909 | |
| 910 | address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); |
| 911 | VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); |
| 912 | return address; |
| 913 | } |
| 914 | |
| 915 | /* Walk all mappings of a given index of a file and writeprotect them */ |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 916 | static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index, |
| 917 | unsigned long pfn) |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 918 | { |
| 919 | struct vm_area_struct *vma; |
Ross Zwisler | f729c8c | 2017-01-10 16:57:24 -0800 | [diff] [blame] | 920 | pte_t pte, *ptep = NULL; |
| 921 | pmd_t *pmdp = NULL; |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 922 | spinlock_t *ptl; |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 923 | |
| 924 | i_mmap_lock_read(mapping); |
| 925 | vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { |
Jérôme Glisse | a4d1a88 | 2017-08-31 17:17:26 -0400 | [diff] [blame] | 926 | unsigned long address, start, end; |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 927 | |
| 928 | cond_resched(); |
| 929 | |
| 930 | if (!(vma->vm_flags & VM_SHARED)) |
| 931 | continue; |
| 932 | |
| 933 | address = pgoff_address(index, vma); |
Jérôme Glisse | a4d1a88 | 2017-08-31 17:17:26 -0400 | [diff] [blame] | 934 | |
| 935 | /* |
| 936 | * Note because we provide start/end to follow_pte_pmd it will |
| 937 | * call mmu_notifier_invalidate_range_start() on our behalf |
| 938 | * before taking any lock. |
| 939 | */ |
| 940 | if (follow_pte_pmd(vma->vm_mm, address, &start, &end, &ptep, &pmdp, &ptl)) |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 941 | continue; |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 942 | |
Jérôme Glisse | 0f10851 | 2017-11-15 17:34:07 -0800 | [diff] [blame] | 943 | /* |
| 944 | * No need to call mmu_notifier_invalidate_range() as we are |
| 945 | * downgrading page table protection not changing it to point |
| 946 | * to a new page. |
| 947 | * |
Mike Rapoport | ad56b73 | 2018-03-21 21:22:47 +0200 | [diff] [blame] | 948 | * See Documentation/vm/mmu_notifier.rst |
Jérôme Glisse | 0f10851 | 2017-11-15 17:34:07 -0800 | [diff] [blame] | 949 | */ |
Ross Zwisler | f729c8c | 2017-01-10 16:57:24 -0800 | [diff] [blame] | 950 | if (pmdp) { |
| 951 | #ifdef CONFIG_FS_DAX_PMD |
| 952 | pmd_t pmd; |
| 953 | |
| 954 | if (pfn != pmd_pfn(*pmdp)) |
| 955 | goto unlock_pmd; |
Linus Torvalds | f6f3732 | 2017-12-15 18:53:22 -0800 | [diff] [blame] | 956 | if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) |
Ross Zwisler | f729c8c | 2017-01-10 16:57:24 -0800 | [diff] [blame] | 957 | goto unlock_pmd; |
| 958 | |
| 959 | flush_cache_page(vma, address, pfn); |
| 960 | pmd = pmdp_huge_clear_flush(vma, address, pmdp); |
| 961 | pmd = pmd_wrprotect(pmd); |
| 962 | pmd = pmd_mkclean(pmd); |
| 963 | set_pmd_at(vma->vm_mm, address, pmdp, pmd); |
Ross Zwisler | f729c8c | 2017-01-10 16:57:24 -0800 | [diff] [blame] | 964 | unlock_pmd: |
Ross Zwisler | f729c8c | 2017-01-10 16:57:24 -0800 | [diff] [blame] | 965 | #endif |
Jan H. Schönherr | ee190ca | 2018-01-31 16:14:04 -0800 | [diff] [blame] | 966 | spin_unlock(ptl); |
Ross Zwisler | f729c8c | 2017-01-10 16:57:24 -0800 | [diff] [blame] | 967 | } else { |
| 968 | if (pfn != pte_pfn(*ptep)) |
| 969 | goto unlock_pte; |
| 970 | if (!pte_dirty(*ptep) && !pte_write(*ptep)) |
| 971 | goto unlock_pte; |
| 972 | |
| 973 | flush_cache_page(vma, address, pfn); |
| 974 | pte = ptep_clear_flush(vma, address, ptep); |
| 975 | pte = pte_wrprotect(pte); |
| 976 | pte = pte_mkclean(pte); |
| 977 | set_pte_at(vma->vm_mm, address, ptep, pte); |
Ross Zwisler | f729c8c | 2017-01-10 16:57:24 -0800 | [diff] [blame] | 978 | unlock_pte: |
| 979 | pte_unmap_unlock(ptep, ptl); |
| 980 | } |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 981 | |
Jérôme Glisse | a4d1a88 | 2017-08-31 17:17:26 -0400 | [diff] [blame] | 982 | mmu_notifier_invalidate_range_end(vma->vm_mm, start, end); |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 983 | } |
| 984 | i_mmap_unlock_read(mapping); |
| 985 | } |
| 986 | |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 987 | static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev, |
| 988 | struct address_space *mapping, void *entry) |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 989 | { |
Dan Williams | 3fe0791 | 2017-10-14 17:13:45 -0700 | [diff] [blame] | 990 | unsigned long pfn; |
| 991 | long ret = 0; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 992 | size_t size; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 993 | |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 994 | /* |
Jan Kara | a6abc2c | 2016-12-14 15:07:47 -0800 | [diff] [blame] | 995 | * A page got tagged dirty in DAX mapping? Something is seriously |
| 996 | * wrong. |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 997 | */ |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 998 | if (WARN_ON(!xa_is_value(entry))) |
Jan Kara | a6abc2c | 2016-12-14 15:07:47 -0800 | [diff] [blame] | 999 | return -EIO; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1000 | |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1001 | if (unlikely(dax_is_locked(entry))) { |
| 1002 | void *old_entry = entry; |
| 1003 | |
| 1004 | entry = get_unlocked_entry(xas); |
| 1005 | |
| 1006 | /* Entry got punched out / reallocated? */ |
| 1007 | if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) |
| 1008 | goto put_unlocked; |
| 1009 | /* |
| 1010 | * Entry got reallocated elsewhere? No need to writeback. |
| 1011 | * We have to compare pfns as we must not bail out due to |
| 1012 | * difference in lockbit or entry type. |
| 1013 | */ |
| 1014 | if (dax_to_pfn(old_entry) != dax_to_pfn(entry)) |
| 1015 | goto put_unlocked; |
| 1016 | if (WARN_ON_ONCE(dax_is_empty_entry(entry) || |
| 1017 | dax_is_zero_entry(entry))) { |
| 1018 | ret = -EIO; |
| 1019 | goto put_unlocked; |
| 1020 | } |
| 1021 | |
| 1022 | /* Another fsync thread may have already done this entry */ |
| 1023 | if (!xas_get_mark(xas, PAGECACHE_TAG_TOWRITE)) |
| 1024 | goto put_unlocked; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1025 | } |
| 1026 | |
Jan Kara | a6abc2c | 2016-12-14 15:07:47 -0800 | [diff] [blame] | 1027 | /* Lock the entry to serialize with page faults */ |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1028 | dax_lock_entry(xas, entry); |
| 1029 | |
Jan Kara | a6abc2c | 2016-12-14 15:07:47 -0800 | [diff] [blame] | 1030 | /* |
| 1031 | * We can clear the tag now but we have to be careful so that concurrent |
| 1032 | * dax_writeback_one() calls for the same index cannot finish before we |
| 1033 | * actually flush the caches. This is achieved as the calls will look |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 1034 | * at the entry only under the i_pages lock and once they do that |
| 1035 | * they will see the entry locked and wait for it to unlock. |
Jan Kara | a6abc2c | 2016-12-14 15:07:47 -0800 | [diff] [blame] | 1036 | */ |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1037 | xas_clear_mark(xas, PAGECACHE_TAG_TOWRITE); |
| 1038 | xas_unlock_irq(xas); |
Jan Kara | a6abc2c | 2016-12-14 15:07:47 -0800 | [diff] [blame] | 1039 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1040 | /* |
| 1041 | * Even if dax_writeback_mapping_range() was given a wbc->range_start |
| 1042 | * in the middle of a PMD, the 'index' we are given will be aligned to |
Dan Williams | 3fe0791 | 2017-10-14 17:13:45 -0700 | [diff] [blame] | 1043 | * the start index of the PMD, as will the pfn we pull from 'entry'. |
| 1044 | * This allows us to flush for PMD_SIZE and not have to worry about |
| 1045 | * partial PMD writebacks. |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1046 | */ |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1047 | pfn = dax_to_pfn(entry); |
| 1048 | size = PAGE_SIZE << dax_entry_order(entry); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1049 | |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1050 | dax_entry_mkclean(mapping, xas->xa_index, pfn); |
Dan Williams | 3fe0791 | 2017-10-14 17:13:45 -0700 | [diff] [blame] | 1051 | dax_flush(dax_dev, page_address(pfn_to_page(pfn)), size); |
Jan Kara | 4b4bb46 | 2016-12-14 15:07:53 -0800 | [diff] [blame] | 1052 | /* |
| 1053 | * After we have flushed the cache, we can clear the dirty tag. There |
| 1054 | * cannot be new dirty data in the pfn after the flush has completed as |
| 1055 | * the pfn mappings are writeprotected and fault waits for mapping |
| 1056 | * entry lock. |
| 1057 | */ |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1058 | xas_reset(xas); |
| 1059 | xas_lock_irq(xas); |
| 1060 | xas_store(xas, entry); |
| 1061 | xas_clear_mark(xas, PAGECACHE_TAG_DIRTY); |
| 1062 | dax_wake_entry(xas, entry, false); |
| 1063 | |
| 1064 | trace_dax_writeback_one(mapping->host, xas->xa_index, |
| 1065 | size >> PAGE_SHIFT); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1066 | return ret; |
| 1067 | |
Jan Kara | a6abc2c | 2016-12-14 15:07:47 -0800 | [diff] [blame] | 1068 | put_unlocked: |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1069 | put_unlocked_entry(xas, entry); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1070 | return ret; |
| 1071 | } |
| 1072 | |
| 1073 | /* |
| 1074 | * Flush the mapping to the persistent domain within the byte range of [start, |
| 1075 | * end]. This is required by data integrity operations to ensure file data is |
| 1076 | * on persistent storage prior to completion of the operation. |
| 1077 | */ |
Ross Zwisler | 7f6d5b5 | 2016-02-26 15:19:55 -0800 | [diff] [blame] | 1078 | int dax_writeback_mapping_range(struct address_space *mapping, |
| 1079 | struct block_device *bdev, struct writeback_control *wbc) |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1080 | { |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1081 | XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1082 | struct inode *inode = mapping->host; |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1083 | pgoff_t end_index = wbc->range_end >> PAGE_SHIFT; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1084 | struct dax_device *dax_dev; |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1085 | void *entry; |
| 1086 | int ret = 0; |
| 1087 | unsigned int scanned = 0; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1088 | |
| 1089 | if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) |
| 1090 | return -EIO; |
| 1091 | |
Ross Zwisler | 7f6d5b5 | 2016-02-26 15:19:55 -0800 | [diff] [blame] | 1092 | if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) |
| 1093 | return 0; |
| 1094 | |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1095 | dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); |
| 1096 | if (!dax_dev) |
| 1097 | return -EIO; |
| 1098 | |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1099 | trace_dax_writeback_range(inode, xas.xa_index, end_index); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1100 | |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1101 | tag_pages_for_writeback(mapping, xas.xa_index, end_index); |
Ross Zwisler | d14a3f4 | 2017-05-08 16:00:10 -0700 | [diff] [blame] | 1102 | |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1103 | xas_lock_irq(&xas); |
| 1104 | xas_for_each_marked(&xas, entry, end_index, PAGECACHE_TAG_TOWRITE) { |
| 1105 | ret = dax_writeback_one(&xas, dax_dev, mapping, entry); |
| 1106 | if (ret < 0) { |
| 1107 | mapping_set_error(mapping, ret); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1108 | break; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1109 | } |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1110 | if (++scanned % XA_CHECK_SCHED) |
| 1111 | continue; |
| 1112 | |
| 1113 | xas_pause(&xas); |
| 1114 | xas_unlock_irq(&xas); |
| 1115 | cond_resched(); |
| 1116 | xas_lock_irq(&xas); |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1117 | } |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1118 | xas_unlock_irq(&xas); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1119 | put_dax(dax_dev); |
Matthew Wilcox | 9fc747f6 | 2018-03-28 16:03:45 -0400 | [diff] [blame] | 1120 | trace_dax_writeback_range_done(inode, xas.xa_index, end_index); |
| 1121 | return ret; |
Ross Zwisler | 9973c98 | 2016-01-22 15:10:47 -0800 | [diff] [blame] | 1122 | } |
| 1123 | EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); |
| 1124 | |
Jan Kara | 31a6f1a | 2017-11-01 16:36:32 +0100 | [diff] [blame] | 1125 | static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 1126 | { |
Linus Torvalds | a3841f9 | 2017-11-17 09:51:57 -0800 | [diff] [blame] | 1127 | return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9; |
Jan Kara | 31a6f1a | 2017-11-01 16:36:32 +0100 | [diff] [blame] | 1128 | } |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 1129 | |
Jan Kara | 5e161e4 | 2017-11-01 16:36:33 +0100 | [diff] [blame] | 1130 | static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size, |
| 1131 | pfn_t *pfnp) |
| 1132 | { |
| 1133 | const sector_t sector = dax_iomap_sector(iomap, pos); |
| 1134 | pgoff_t pgoff; |
Jan Kara | 5e161e4 | 2017-11-01 16:36:33 +0100 | [diff] [blame] | 1135 | int id, rc; |
| 1136 | long length; |
| 1137 | |
| 1138 | rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1139 | if (rc) |
| 1140 | return rc; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1141 | id = dax_read_lock(); |
Jan Kara | 5e161e4 | 2017-11-01 16:36:33 +0100 | [diff] [blame] | 1142 | length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), |
Huaisheng Ye | 86ed913 | 2018-07-30 15:15:48 +0800 | [diff] [blame] | 1143 | NULL, pfnp); |
Jan Kara | 5e161e4 | 2017-11-01 16:36:33 +0100 | [diff] [blame] | 1144 | if (length < 0) { |
| 1145 | rc = length; |
| 1146 | goto out; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1147 | } |
Jan Kara | 5e161e4 | 2017-11-01 16:36:33 +0100 | [diff] [blame] | 1148 | rc = -EINVAL; |
| 1149 | if (PFN_PHYS(length) < size) |
| 1150 | goto out; |
| 1151 | if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) |
| 1152 | goto out; |
| 1153 | /* For larger pages we need devmap */ |
| 1154 | if (length > 1 && !pfn_t_devmap(*pfnp)) |
| 1155 | goto out; |
| 1156 | rc = 0; |
| 1157 | out: |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1158 | dax_read_unlock(id); |
Jan Kara | 5e161e4 | 2017-11-01 16:36:33 +0100 | [diff] [blame] | 1159 | return rc; |
Matthew Wilcox | f7ca90b | 2015-02-16 15:59:02 -0800 | [diff] [blame] | 1160 | } |
| 1161 | |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 1162 | /* |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 1163 | * The user has performed a load from a hole in the file. Allocating a new |
| 1164 | * page in the file would cause excessive storage usage for workloads with |
| 1165 | * sparse files. Instead we insert a read-only mapping of the 4k zero page. |
| 1166 | * If this page is ever written to we will re-fault and change the mapping to |
| 1167 | * point to real DAX storage instead. |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 1168 | */ |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1169 | static vm_fault_t dax_load_hole(struct address_space *mapping, void *entry, |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 1170 | struct vm_fault *vmf) |
| 1171 | { |
| 1172 | struct inode *inode = mapping->host; |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 1173 | unsigned long vaddr = vmf->address; |
Matthew Wilcox | b90ca5c | 2018-09-11 21:27:44 -0700 | [diff] [blame] | 1174 | pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr)); |
| 1175 | vm_fault_t ret; |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 1176 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1177 | dax_insert_entry(mapping, vmf, entry, pfn, |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 1178 | DAX_ZERO_PAGE, false); |
| 1179 | |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1180 | ret = vmf_insert_mixed(vmf->vma, vaddr, pfn); |
Ross Zwisler | e30331f | 2017-09-06 16:18:39 -0700 | [diff] [blame] | 1181 | trace_dax_load_hole(inode, vmf, ret); |
| 1182 | return ret; |
| 1183 | } |
| 1184 | |
Vishal Verma | 4b0228f | 2016-04-21 15:13:46 -0400 | [diff] [blame] | 1185 | static bool dax_range_is_aligned(struct block_device *bdev, |
| 1186 | unsigned int offset, unsigned int length) |
| 1187 | { |
| 1188 | unsigned short sector_size = bdev_logical_block_size(bdev); |
| 1189 | |
| 1190 | if (!IS_ALIGNED(offset, sector_size)) |
| 1191 | return false; |
| 1192 | if (!IS_ALIGNED(length, sector_size)) |
| 1193 | return false; |
| 1194 | |
| 1195 | return true; |
| 1196 | } |
| 1197 | |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1198 | int __dax_zero_page_range(struct block_device *bdev, |
| 1199 | struct dax_device *dax_dev, sector_t sector, |
| 1200 | unsigned int offset, unsigned int size) |
Christoph Hellwig | 679c8bd | 2016-05-09 10:47:04 +0200 | [diff] [blame] | 1201 | { |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1202 | if (dax_range_is_aligned(bdev, offset, size)) { |
| 1203 | sector_t start_sector = sector + (offset >> 9); |
Vishal Verma | 4b0228f | 2016-04-21 15:13:46 -0400 | [diff] [blame] | 1204 | |
| 1205 | return blkdev_issue_zeroout(bdev, start_sector, |
Linus Torvalds | 53ef7d0 | 2017-05-05 18:49:20 -0700 | [diff] [blame] | 1206 | size >> 9, GFP_NOFS, 0); |
Vishal Verma | 4b0228f | 2016-04-21 15:13:46 -0400 | [diff] [blame] | 1207 | } else { |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1208 | pgoff_t pgoff; |
| 1209 | long rc, id; |
| 1210 | void *kaddr; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1211 | |
Dan Williams | e84b83b | 2017-05-10 19:38:13 -0700 | [diff] [blame] | 1212 | rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1213 | if (rc) |
| 1214 | return rc; |
| 1215 | |
| 1216 | id = dax_read_lock(); |
Huaisheng Ye | 86ed913 | 2018-07-30 15:15:48 +0800 | [diff] [blame] | 1217 | rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, NULL); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1218 | if (rc < 0) { |
| 1219 | dax_read_unlock(id); |
| 1220 | return rc; |
| 1221 | } |
Dan Williams | 81f5587 | 2017-05-29 13:12:20 -0700 | [diff] [blame] | 1222 | memset(kaddr + offset, 0, size); |
Mikulas Patocka | c3ca015 | 2017-08-31 21:47:43 -0400 | [diff] [blame] | 1223 | dax_flush(dax_dev, kaddr + offset, size); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1224 | dax_read_unlock(id); |
Vishal Verma | 4b0228f | 2016-04-21 15:13:46 -0400 | [diff] [blame] | 1225 | } |
Christoph Hellwig | 679c8bd | 2016-05-09 10:47:04 +0200 | [diff] [blame] | 1226 | return 0; |
| 1227 | } |
| 1228 | EXPORT_SYMBOL_GPL(__dax_zero_page_range); |
| 1229 | |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1230 | static loff_t |
Ross Zwisler | 11c59c9 | 2016-11-08 11:32:46 +1100 | [diff] [blame] | 1231 | dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1232 | struct iomap *iomap) |
| 1233 | { |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1234 | struct block_device *bdev = iomap->bdev; |
| 1235 | struct dax_device *dax_dev = iomap->dax_dev; |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1236 | struct iov_iter *iter = data; |
| 1237 | loff_t end = pos + length, done = 0; |
| 1238 | ssize_t ret = 0; |
Dan Williams | a77d478 | 2018-03-16 17:36:44 -0700 | [diff] [blame] | 1239 | size_t xfer; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1240 | int id; |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1241 | |
| 1242 | if (iov_iter_rw(iter) == READ) { |
| 1243 | end = min(end, i_size_read(inode)); |
| 1244 | if (pos >= end) |
| 1245 | return 0; |
| 1246 | |
| 1247 | if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) |
| 1248 | return iov_iter_zero(min(length, end - pos), iter); |
| 1249 | } |
| 1250 | |
| 1251 | if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) |
| 1252 | return -EIO; |
| 1253 | |
Jan Kara | e3fce68 | 2016-08-10 17:10:28 +0200 | [diff] [blame] | 1254 | /* |
| 1255 | * Write can allocate block for an area which has a hole page mapped |
| 1256 | * into page tables. We have to tear down these mappings so that data |
| 1257 | * written by write(2) is visible in mmap. |
| 1258 | */ |
Jan Kara | cd65637 | 2017-05-12 15:46:50 -0700 | [diff] [blame] | 1259 | if (iomap->flags & IOMAP_F_NEW) { |
Jan Kara | e3fce68 | 2016-08-10 17:10:28 +0200 | [diff] [blame] | 1260 | invalidate_inode_pages2_range(inode->i_mapping, |
| 1261 | pos >> PAGE_SHIFT, |
| 1262 | (end - 1) >> PAGE_SHIFT); |
| 1263 | } |
| 1264 | |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1265 | id = dax_read_lock(); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1266 | while (pos < end) { |
| 1267 | unsigned offset = pos & (PAGE_SIZE - 1); |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1268 | const size_t size = ALIGN(length + offset, PAGE_SIZE); |
| 1269 | const sector_t sector = dax_iomap_sector(iomap, pos); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1270 | ssize_t map_len; |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1271 | pgoff_t pgoff; |
| 1272 | void *kaddr; |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1273 | |
Michal Hocko | d1908f5 | 2017-02-03 13:13:26 -0800 | [diff] [blame] | 1274 | if (fatal_signal_pending(current)) { |
| 1275 | ret = -EINTR; |
| 1276 | break; |
| 1277 | } |
| 1278 | |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1279 | ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); |
| 1280 | if (ret) |
| 1281 | break; |
| 1282 | |
| 1283 | map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), |
Huaisheng Ye | 86ed913 | 2018-07-30 15:15:48 +0800 | [diff] [blame] | 1284 | &kaddr, NULL); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1285 | if (map_len < 0) { |
| 1286 | ret = map_len; |
| 1287 | break; |
| 1288 | } |
| 1289 | |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1290 | map_len = PFN_PHYS(map_len); |
| 1291 | kaddr += offset; |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1292 | map_len -= offset; |
| 1293 | if (map_len > end - pos) |
| 1294 | map_len = end - pos; |
| 1295 | |
Ross Zwisler | a2e050f | 2017-09-06 16:18:54 -0700 | [diff] [blame] | 1296 | /* |
| 1297 | * The userspace address for the memory copy has already been |
| 1298 | * validated via access_ok() in either vfs_read() or |
| 1299 | * vfs_write(), depending on which operation we are doing. |
| 1300 | */ |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1301 | if (iov_iter_rw(iter) == WRITE) |
Dan Williams | a77d478 | 2018-03-16 17:36:44 -0700 | [diff] [blame] | 1302 | xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr, |
Dan Williams | fec5377 | 2017-05-29 21:56:49 -0700 | [diff] [blame] | 1303 | map_len, iter); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1304 | else |
Dan Williams | a77d478 | 2018-03-16 17:36:44 -0700 | [diff] [blame] | 1305 | xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr, |
Dan Williams | b3a9a0c | 2018-05-02 06:46:33 -0700 | [diff] [blame] | 1306 | map_len, iter); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1307 | |
Dan Williams | a77d478 | 2018-03-16 17:36:44 -0700 | [diff] [blame] | 1308 | pos += xfer; |
| 1309 | length -= xfer; |
| 1310 | done += xfer; |
| 1311 | |
| 1312 | if (xfer == 0) |
| 1313 | ret = -EFAULT; |
| 1314 | if (xfer < map_len) |
| 1315 | break; |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1316 | } |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1317 | dax_read_unlock(id); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1318 | |
| 1319 | return done ? done : ret; |
| 1320 | } |
| 1321 | |
| 1322 | /** |
Ross Zwisler | 11c59c9 | 2016-11-08 11:32:46 +1100 | [diff] [blame] | 1323 | * dax_iomap_rw - Perform I/O to a DAX file |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1324 | * @iocb: The control block for this I/O |
| 1325 | * @iter: The addresses to do I/O from or to |
| 1326 | * @ops: iomap ops passed from the file system |
| 1327 | * |
| 1328 | * This function performs read and write operations to directly mapped |
| 1329 | * persistent memory. The callers needs to take care of read/write exclusion |
| 1330 | * and evicting any page cache pages in the region under I/O. |
| 1331 | */ |
| 1332 | ssize_t |
Ross Zwisler | 11c59c9 | 2016-11-08 11:32:46 +1100 | [diff] [blame] | 1333 | dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, |
Christoph Hellwig | 8ff6daa | 2017-01-27 23:20:26 -0800 | [diff] [blame] | 1334 | const struct iomap_ops *ops) |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1335 | { |
| 1336 | struct address_space *mapping = iocb->ki_filp->f_mapping; |
| 1337 | struct inode *inode = mapping->host; |
| 1338 | loff_t pos = iocb->ki_pos, ret = 0, done = 0; |
| 1339 | unsigned flags = 0; |
| 1340 | |
Christoph Hellwig | 168316d | 2017-02-08 14:43:13 -0500 | [diff] [blame] | 1341 | if (iov_iter_rw(iter) == WRITE) { |
| 1342 | lockdep_assert_held_exclusive(&inode->i_rwsem); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1343 | flags |= IOMAP_WRITE; |
Christoph Hellwig | 168316d | 2017-02-08 14:43:13 -0500 | [diff] [blame] | 1344 | } else { |
| 1345 | lockdep_assert_held(&inode->i_rwsem); |
| 1346 | } |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1347 | |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1348 | while (iov_iter_count(iter)) { |
| 1349 | ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, |
Ross Zwisler | 11c59c9 | 2016-11-08 11:32:46 +1100 | [diff] [blame] | 1350 | iter, dax_iomap_actor); |
Christoph Hellwig | a254e56 | 2016-09-19 11:24:49 +1000 | [diff] [blame] | 1351 | if (ret <= 0) |
| 1352 | break; |
| 1353 | pos += ret; |
| 1354 | done += ret; |
| 1355 | } |
| 1356 | |
| 1357 | iocb->ki_pos += done; |
| 1358 | return done ? done : ret; |
| 1359 | } |
Ross Zwisler | 11c59c9 | 2016-11-08 11:32:46 +1100 | [diff] [blame] | 1360 | EXPORT_SYMBOL_GPL(dax_iomap_rw); |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1361 | |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1362 | static vm_fault_t dax_fault_return(int error) |
Jan Kara | 9f141d6 | 2016-10-19 14:34:31 +0200 | [diff] [blame] | 1363 | { |
| 1364 | if (error == 0) |
| 1365 | return VM_FAULT_NOPAGE; |
| 1366 | if (error == -ENOMEM) |
| 1367 | return VM_FAULT_OOM; |
| 1368 | return VM_FAULT_SIGBUS; |
| 1369 | } |
| 1370 | |
Dan Williams | aaa422c | 2017-11-13 16:38:44 -0800 | [diff] [blame] | 1371 | /* |
| 1372 | * MAP_SYNC on a dax mapping guarantees dirty metadata is |
| 1373 | * flushed on write-faults (non-cow), but not read-faults. |
| 1374 | */ |
| 1375 | static bool dax_fault_is_synchronous(unsigned long flags, |
| 1376 | struct vm_area_struct *vma, struct iomap *iomap) |
| 1377 | { |
| 1378 | return (flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) |
| 1379 | && (iomap->flags & IOMAP_F_DIRTY); |
| 1380 | } |
| 1381 | |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1382 | static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, |
Jan Kara | c0b2462 | 2018-01-07 16:38:43 -0500 | [diff] [blame] | 1383 | int *iomap_errp, const struct iomap_ops *ops) |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1384 | { |
Jan Kara | a0987ad | 2017-11-01 16:36:34 +0100 | [diff] [blame] | 1385 | struct vm_area_struct *vma = vmf->vma; |
| 1386 | struct address_space *mapping = vma->vm_file->f_mapping; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1387 | struct inode *inode = mapping->host; |
Jan Kara | 1a29d85 | 2016-12-14 15:07:01 -0800 | [diff] [blame] | 1388 | unsigned long vaddr = vmf->address; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1389 | loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1390 | struct iomap iomap = { 0 }; |
Jan Kara | 9484ab1 | 2016-11-10 10:26:50 +1100 | [diff] [blame] | 1391 | unsigned flags = IOMAP_FAULT; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1392 | int error, major = 0; |
Jan Kara | d2c43ef | 2017-11-01 16:36:35 +0100 | [diff] [blame] | 1393 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1394 | bool sync; |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1395 | vm_fault_t ret = 0; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1396 | void *entry; |
Jan Kara | 1b5a1cb | 2017-11-01 16:36:36 +0100 | [diff] [blame] | 1397 | pfn_t pfn; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1398 | |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1399 | trace_dax_pte_fault(inode, vmf, ret); |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1400 | /* |
| 1401 | * Check whether offset isn't beyond end of file now. Caller is supposed |
| 1402 | * to hold locks serializing us with truncate / punch hole so this is |
| 1403 | * a reliable test. |
| 1404 | */ |
Ross Zwisler | a9c42b3 | 2017-05-08 16:00:00 -0700 | [diff] [blame] | 1405 | if (pos >= i_size_read(inode)) { |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1406 | ret = VM_FAULT_SIGBUS; |
Ross Zwisler | a9c42b3 | 2017-05-08 16:00:00 -0700 | [diff] [blame] | 1407 | goto out; |
| 1408 | } |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1409 | |
Jan Kara | d2c43ef | 2017-11-01 16:36:35 +0100 | [diff] [blame] | 1410 | if (write && !vmf->cow_page) |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1411 | flags |= IOMAP_WRITE; |
| 1412 | |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1413 | entry = grab_mapping_entry(mapping, vmf->pgoff, 0); |
| 1414 | if (IS_ERR(entry)) { |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1415 | ret = dax_fault_return(PTR_ERR(entry)); |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1416 | goto out; |
| 1417 | } |
| 1418 | |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1419 | /* |
Ross Zwisler | e209392 | 2017-06-02 14:46:37 -0700 | [diff] [blame] | 1420 | * It is possible, particularly with mixed reads & writes to private |
| 1421 | * mappings, that we have raced with a PMD fault that overlaps with |
| 1422 | * the PTE we need to set up. If so just return and the fault will be |
| 1423 | * retried. |
| 1424 | */ |
| 1425 | if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1426 | ret = VM_FAULT_NOPAGE; |
Ross Zwisler | e209392 | 2017-06-02 14:46:37 -0700 | [diff] [blame] | 1427 | goto unlock_entry; |
| 1428 | } |
| 1429 | |
| 1430 | /* |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1431 | * Note that we don't bother to use iomap_apply here: DAX required |
| 1432 | * the file system block size to be equal the page size, which means |
| 1433 | * that we never have to deal with more than a single extent here. |
| 1434 | */ |
| 1435 | error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); |
Jan Kara | c0b2462 | 2018-01-07 16:38:43 -0500 | [diff] [blame] | 1436 | if (iomap_errp) |
| 1437 | *iomap_errp = error; |
Ross Zwisler | a9c42b3 | 2017-05-08 16:00:00 -0700 | [diff] [blame] | 1438 | if (error) { |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1439 | ret = dax_fault_return(error); |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1440 | goto unlock_entry; |
Ross Zwisler | a9c42b3 | 2017-05-08 16:00:00 -0700 | [diff] [blame] | 1441 | } |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1442 | if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1443 | error = -EIO; /* fs corruption? */ |
| 1444 | goto error_finish_iomap; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1445 | } |
| 1446 | |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1447 | if (vmf->cow_page) { |
Jan Kara | 31a6f1a | 2017-11-01 16:36:32 +0100 | [diff] [blame] | 1448 | sector_t sector = dax_iomap_sector(&iomap, pos); |
| 1449 | |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1450 | switch (iomap.type) { |
| 1451 | case IOMAP_HOLE: |
| 1452 | case IOMAP_UNWRITTEN: |
| 1453 | clear_user_highpage(vmf->cow_page, vaddr); |
| 1454 | break; |
| 1455 | case IOMAP_MAPPED: |
Dan Williams | cccbce6 | 2017-01-27 13:31:42 -0800 | [diff] [blame] | 1456 | error = copy_user_dax(iomap.bdev, iomap.dax_dev, |
| 1457 | sector, PAGE_SIZE, vmf->cow_page, vaddr); |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1458 | break; |
| 1459 | default: |
| 1460 | WARN_ON_ONCE(1); |
| 1461 | error = -EIO; |
| 1462 | break; |
| 1463 | } |
| 1464 | |
| 1465 | if (error) |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1466 | goto error_finish_iomap; |
Jan Kara | b1aa812 | 2016-12-14 15:07:24 -0800 | [diff] [blame] | 1467 | |
| 1468 | __SetPageUptodate(vmf->cow_page); |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1469 | ret = finish_fault(vmf); |
| 1470 | if (!ret) |
| 1471 | ret = VM_FAULT_DONE_COW; |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1472 | goto finish_iomap; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1473 | } |
| 1474 | |
Dan Williams | aaa422c | 2017-11-13 16:38:44 -0800 | [diff] [blame] | 1475 | sync = dax_fault_is_synchronous(flags, vma, &iomap); |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1476 | |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1477 | switch (iomap.type) { |
| 1478 | case IOMAP_MAPPED: |
| 1479 | if (iomap.flags & IOMAP_F_NEW) { |
| 1480 | count_vm_event(PGMAJFAULT); |
Jan Kara | a0987ad | 2017-11-01 16:36:34 +0100 | [diff] [blame] | 1481 | count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1482 | major = VM_FAULT_MAJOR; |
| 1483 | } |
Jan Kara | 1b5a1cb | 2017-11-01 16:36:36 +0100 | [diff] [blame] | 1484 | error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); |
| 1485 | if (error < 0) |
| 1486 | goto error_finish_iomap; |
| 1487 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1488 | entry = dax_insert_entry(mapping, vmf, entry, pfn, |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1489 | 0, write && !sync); |
Jan Kara | 1b5a1cb | 2017-11-01 16:36:36 +0100 | [diff] [blame] | 1490 | |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1491 | /* |
| 1492 | * If we are doing synchronous page fault and inode needs fsync, |
| 1493 | * we can insert PTE into page tables only after that happens. |
| 1494 | * Skip insertion for now and return the pfn so that caller can |
| 1495 | * insert it after fsync is done. |
| 1496 | */ |
| 1497 | if (sync) { |
| 1498 | if (WARN_ON_ONCE(!pfnp)) { |
| 1499 | error = -EIO; |
| 1500 | goto error_finish_iomap; |
| 1501 | } |
| 1502 | *pfnp = pfn; |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1503 | ret = VM_FAULT_NEEDDSYNC | major; |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1504 | goto finish_iomap; |
| 1505 | } |
Jan Kara | 1b5a1cb | 2017-11-01 16:36:36 +0100 | [diff] [blame] | 1506 | trace_dax_insert_mapping(inode, vmf, entry); |
| 1507 | if (write) |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1508 | ret = vmf_insert_mixed_mkwrite(vma, vaddr, pfn); |
Jan Kara | 1b5a1cb | 2017-11-01 16:36:36 +0100 | [diff] [blame] | 1509 | else |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1510 | ret = vmf_insert_mixed(vma, vaddr, pfn); |
Jan Kara | 1b5a1cb | 2017-11-01 16:36:36 +0100 | [diff] [blame] | 1511 | |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1512 | goto finish_iomap; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1513 | case IOMAP_UNWRITTEN: |
| 1514 | case IOMAP_HOLE: |
Jan Kara | d2c43ef | 2017-11-01 16:36:35 +0100 | [diff] [blame] | 1515 | if (!write) { |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1516 | ret = dax_load_hole(mapping, entry, vmf); |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1517 | goto finish_iomap; |
Ross Zwisler | 1550290 | 2016-11-08 11:33:26 +1100 | [diff] [blame] | 1518 | } |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1519 | /*FALLTHRU*/ |
| 1520 | default: |
| 1521 | WARN_ON_ONCE(1); |
| 1522 | error = -EIO; |
| 1523 | break; |
| 1524 | } |
| 1525 | |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1526 | error_finish_iomap: |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1527 | ret = dax_fault_return(error); |
Jan Kara | 9f141d6 | 2016-10-19 14:34:31 +0200 | [diff] [blame] | 1528 | finish_iomap: |
| 1529 | if (ops->iomap_end) { |
| 1530 | int copied = PAGE_SIZE; |
| 1531 | |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1532 | if (ret & VM_FAULT_ERROR) |
Jan Kara | 9f141d6 | 2016-10-19 14:34:31 +0200 | [diff] [blame] | 1533 | copied = 0; |
| 1534 | /* |
| 1535 | * The fault is done by now and there's no way back (other |
| 1536 | * thread may be already happily using PTE we have installed). |
| 1537 | * Just ignore error from ->iomap_end since we cannot do much |
| 1538 | * with it. |
| 1539 | */ |
| 1540 | ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); |
Ross Zwisler | 1550290 | 2016-11-08 11:33:26 +1100 | [diff] [blame] | 1541 | } |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1542 | unlock_entry: |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 1543 | put_locked_mapping_entry(mapping, vmf->pgoff); |
Jan Kara | 13e451f | 2017-05-12 15:46:57 -0700 | [diff] [blame] | 1544 | out: |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1545 | trace_dax_pte_fault_done(inode, vmf, ret); |
| 1546 | return ret | major; |
Christoph Hellwig | a7d73fe | 2016-09-19 11:24:50 +1000 | [diff] [blame] | 1547 | } |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1548 | |
| 1549 | #ifdef CONFIG_FS_DAX_PMD |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1550 | static vm_fault_t dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 1551 | void *entry) |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1552 | { |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1553 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
| 1554 | unsigned long pmd_addr = vmf->address & PMD_MASK; |
Ross Zwisler | 653b2ea | 2017-02-22 15:39:57 -0800 | [diff] [blame] | 1555 | struct inode *inode = mapping->host; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1556 | struct page *zero_page; |
Ross Zwisler | 653b2ea | 2017-02-22 15:39:57 -0800 | [diff] [blame] | 1557 | void *ret = NULL; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1558 | spinlock_t *ptl; |
| 1559 | pmd_t pmd_entry; |
Dan Williams | 3fe0791 | 2017-10-14 17:13:45 -0700 | [diff] [blame] | 1560 | pfn_t pfn; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1561 | |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1562 | zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1563 | |
| 1564 | if (unlikely(!zero_page)) |
Ross Zwisler | 653b2ea | 2017-02-22 15:39:57 -0800 | [diff] [blame] | 1565 | goto fallback; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1566 | |
Dan Williams | 3fe0791 | 2017-10-14 17:13:45 -0700 | [diff] [blame] | 1567 | pfn = page_to_pfn_t(zero_page); |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1568 | ret = dax_insert_entry(mapping, vmf, entry, pfn, |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 1569 | DAX_PMD | DAX_ZERO_PAGE, false); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1570 | |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1571 | ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); |
| 1572 | if (!pmd_none(*(vmf->pmd))) { |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1573 | spin_unlock(ptl); |
Ross Zwisler | 653b2ea | 2017-02-22 15:39:57 -0800 | [diff] [blame] | 1574 | goto fallback; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1575 | } |
| 1576 | |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1577 | pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1578 | pmd_entry = pmd_mkhuge(pmd_entry); |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1579 | set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1580 | spin_unlock(ptl); |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1581 | trace_dax_pmd_load_hole(inode, vmf, zero_page, ret); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1582 | return VM_FAULT_NOPAGE; |
Ross Zwisler | 653b2ea | 2017-02-22 15:39:57 -0800 | [diff] [blame] | 1583 | |
| 1584 | fallback: |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1585 | trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, ret); |
Ross Zwisler | 653b2ea | 2017-02-22 15:39:57 -0800 | [diff] [blame] | 1586 | return VM_FAULT_FALLBACK; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1587 | } |
| 1588 | |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1589 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
Dave Jiang | a2d5816 | 2017-02-24 14:56:59 -0800 | [diff] [blame] | 1590 | const struct iomap_ops *ops) |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1591 | { |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1592 | struct vm_area_struct *vma = vmf->vma; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1593 | struct address_space *mapping = vma->vm_file->f_mapping; |
Dave Jiang | d8a849e | 2017-02-22 15:40:03 -0800 | [diff] [blame] | 1594 | unsigned long pmd_addr = vmf->address & PMD_MASK; |
| 1595 | bool write = vmf->flags & FAULT_FLAG_WRITE; |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1596 | bool sync; |
Jan Kara | 9484ab1 | 2016-11-10 10:26:50 +1100 | [diff] [blame] | 1597 | unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1598 | struct inode *inode = mapping->host; |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1599 | vm_fault_t result = VM_FAULT_FALLBACK; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1600 | struct iomap iomap = { 0 }; |
| 1601 | pgoff_t max_pgoff, pgoff; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1602 | void *entry; |
| 1603 | loff_t pos; |
| 1604 | int error; |
Jan Kara | 302a5e3 | 2017-11-01 16:36:37 +0100 | [diff] [blame] | 1605 | pfn_t pfn; |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1606 | |
Ross Zwisler | 282a8e0 | 2017-02-22 15:39:50 -0800 | [diff] [blame] | 1607 | /* |
| 1608 | * Check whether offset isn't beyond end of file now. Caller is |
| 1609 | * supposed to hold locks serializing us with truncate / punch hole so |
| 1610 | * this is a reliable test. |
| 1611 | */ |
| 1612 | pgoff = linear_page_index(vma, pmd_addr); |
Jeff Moyer | 957ac8c | 2017-11-14 20:37:27 -0500 | [diff] [blame] | 1613 | max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); |
Ross Zwisler | 282a8e0 | 2017-02-22 15:39:50 -0800 | [diff] [blame] | 1614 | |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1615 | trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); |
Ross Zwisler | 282a8e0 | 2017-02-22 15:39:50 -0800 | [diff] [blame] | 1616 | |
Ross Zwisler | fffa281 | 2017-08-25 15:55:36 -0700 | [diff] [blame] | 1617 | /* |
| 1618 | * Make sure that the faulting address's PMD offset (color) matches |
| 1619 | * the PMD offset from the start of the file. This is necessary so |
| 1620 | * that a PMD range in the page table overlaps exactly with a PMD |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1621 | * range in the page cache. |
Ross Zwisler | fffa281 | 2017-08-25 15:55:36 -0700 | [diff] [blame] | 1622 | */ |
| 1623 | if ((vmf->pgoff & PG_PMD_COLOUR) != |
| 1624 | ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) |
| 1625 | goto fallback; |
| 1626 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1627 | /* Fall back to PTEs if we're going to COW */ |
| 1628 | if (write && !(vma->vm_flags & VM_SHARED)) |
| 1629 | goto fallback; |
| 1630 | |
| 1631 | /* If the PMD would extend outside the VMA */ |
| 1632 | if (pmd_addr < vma->vm_start) |
| 1633 | goto fallback; |
| 1634 | if ((pmd_addr + PMD_SIZE) > vma->vm_end) |
| 1635 | goto fallback; |
| 1636 | |
Jeff Moyer | 957ac8c | 2017-11-14 20:37:27 -0500 | [diff] [blame] | 1637 | if (pgoff >= max_pgoff) { |
Ross Zwisler | 282a8e0 | 2017-02-22 15:39:50 -0800 | [diff] [blame] | 1638 | result = VM_FAULT_SIGBUS; |
| 1639 | goto out; |
| 1640 | } |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1641 | |
| 1642 | /* If the PMD would extend beyond the file size */ |
Jeff Moyer | 957ac8c | 2017-11-14 20:37:27 -0500 | [diff] [blame] | 1643 | if ((pgoff | PG_PMD_COLOUR) >= max_pgoff) |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1644 | goto fallback; |
| 1645 | |
| 1646 | /* |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 1647 | * grab_mapping_entry() will make sure we get a 2MiB empty entry, a |
| 1648 | * 2MiB zero page entry or a DAX PMD. If it can't (because a 4k page |
| 1649 | * is already in the tree, for instance), it will return -EEXIST and |
| 1650 | * we just fall back to 4k entries. |
Jan Kara | 9f141d6 | 2016-10-19 14:34:31 +0200 | [diff] [blame] | 1651 | */ |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 1652 | entry = grab_mapping_entry(mapping, pgoff, DAX_PMD); |
Jan Kara | 9f141d6 | 2016-10-19 14:34:31 +0200 | [diff] [blame] | 1653 | if (IS_ERR(entry)) |
Ross Zwisler | 876f294 | 2017-05-12 15:47:00 -0700 | [diff] [blame] | 1654 | goto fallback; |
| 1655 | |
| 1656 | /* |
Ross Zwisler | e209392 | 2017-06-02 14:46:37 -0700 | [diff] [blame] | 1657 | * It is possible, particularly with mixed reads & writes to private |
| 1658 | * mappings, that we have raced with a PTE fault that overlaps with |
| 1659 | * the PMD we need to set up. If so just return and the fault will be |
| 1660 | * retried. |
| 1661 | */ |
| 1662 | if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && |
| 1663 | !pmd_devmap(*vmf->pmd)) { |
| 1664 | result = 0; |
| 1665 | goto unlock_entry; |
| 1666 | } |
| 1667 | |
| 1668 | /* |
Ross Zwisler | 876f294 | 2017-05-12 15:47:00 -0700 | [diff] [blame] | 1669 | * Note that we don't use iomap_apply here. We aren't doing I/O, only |
| 1670 | * setting up a mapping, so really we're using iomap_begin() as a way |
| 1671 | * to look up our filesystem block. |
| 1672 | */ |
| 1673 | pos = (loff_t)pgoff << PAGE_SHIFT; |
| 1674 | error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); |
| 1675 | if (error) |
| 1676 | goto unlock_entry; |
| 1677 | |
| 1678 | if (iomap.offset + iomap.length < pos + PMD_SIZE) |
Jan Kara | 9f141d6 | 2016-10-19 14:34:31 +0200 | [diff] [blame] | 1679 | goto finish_iomap; |
| 1680 | |
Dan Williams | aaa422c | 2017-11-13 16:38:44 -0800 | [diff] [blame] | 1681 | sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1682 | |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1683 | switch (iomap.type) { |
| 1684 | case IOMAP_MAPPED: |
Jan Kara | 302a5e3 | 2017-11-01 16:36:37 +0100 | [diff] [blame] | 1685 | error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn); |
| 1686 | if (error < 0) |
| 1687 | goto finish_iomap; |
| 1688 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1689 | entry = dax_insert_entry(mapping, vmf, entry, pfn, |
Matthew Wilcox | 3159f94 | 2017-11-03 13:30:42 -0400 | [diff] [blame] | 1690 | DAX_PMD, write && !sync); |
Jan Kara | 302a5e3 | 2017-11-01 16:36:37 +0100 | [diff] [blame] | 1691 | |
Jan Kara | caa51d2 | 2017-11-01 16:36:42 +0100 | [diff] [blame] | 1692 | /* |
| 1693 | * If we are doing synchronous page fault and inode needs fsync, |
| 1694 | * we can insert PMD into page tables only after that happens. |
| 1695 | * Skip insertion for now and return the pfn so that caller can |
| 1696 | * insert it after fsync is done. |
| 1697 | */ |
| 1698 | if (sync) { |
| 1699 | if (WARN_ON_ONCE(!pfnp)) |
| 1700 | goto finish_iomap; |
| 1701 | *pfnp = pfn; |
| 1702 | result = VM_FAULT_NEEDDSYNC; |
| 1703 | goto finish_iomap; |
| 1704 | } |
| 1705 | |
Jan Kara | 302a5e3 | 2017-11-01 16:36:37 +0100 | [diff] [blame] | 1706 | trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); |
| 1707 | result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, |
| 1708 | write); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1709 | break; |
| 1710 | case IOMAP_UNWRITTEN: |
| 1711 | case IOMAP_HOLE: |
| 1712 | if (WARN_ON_ONCE(write)) |
Ross Zwisler | 876f294 | 2017-05-12 15:47:00 -0700 | [diff] [blame] | 1713 | break; |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 1714 | result = dax_pmd_load_hole(vmf, &iomap, entry); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1715 | break; |
| 1716 | default: |
| 1717 | WARN_ON_ONCE(1); |
| 1718 | break; |
| 1719 | } |
| 1720 | |
Jan Kara | 9f141d6 | 2016-10-19 14:34:31 +0200 | [diff] [blame] | 1721 | finish_iomap: |
| 1722 | if (ops->iomap_end) { |
| 1723 | int copied = PMD_SIZE; |
| 1724 | |
| 1725 | if (result == VM_FAULT_FALLBACK) |
| 1726 | copied = 0; |
| 1727 | /* |
| 1728 | * The fault is done by now and there's no way back (other |
| 1729 | * thread may be already happily using PMD we have installed). |
| 1730 | * Just ignore error from ->iomap_end since we cannot do much |
| 1731 | * with it. |
| 1732 | */ |
| 1733 | ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, |
| 1734 | &iomap); |
| 1735 | } |
Ross Zwisler | 876f294 | 2017-05-12 15:47:00 -0700 | [diff] [blame] | 1736 | unlock_entry: |
Ross Zwisler | 91d25ba | 2017-09-06 16:18:43 -0700 | [diff] [blame] | 1737 | put_locked_mapping_entry(mapping, pgoff); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1738 | fallback: |
| 1739 | if (result == VM_FAULT_FALLBACK) { |
Dave Jiang | d8a849e | 2017-02-22 15:40:03 -0800 | [diff] [blame] | 1740 | split_huge_pmd(vma, vmf->pmd, vmf->address); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1741 | count_vm_event(THP_FAULT_FALLBACK); |
| 1742 | } |
Ross Zwisler | 282a8e0 | 2017-02-22 15:39:50 -0800 | [diff] [blame] | 1743 | out: |
Dave Jiang | f420039 | 2017-02-22 15:40:06 -0800 | [diff] [blame] | 1744 | trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1745 | return result; |
| 1746 | } |
Dave Jiang | a2d5816 | 2017-02-24 14:56:59 -0800 | [diff] [blame] | 1747 | #else |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1748 | static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, |
Arnd Bergmann | 01cddfe | 2017-02-27 14:26:44 -0800 | [diff] [blame] | 1749 | const struct iomap_ops *ops) |
Dave Jiang | a2d5816 | 2017-02-24 14:56:59 -0800 | [diff] [blame] | 1750 | { |
| 1751 | return VM_FAULT_FALLBACK; |
| 1752 | } |
Ross Zwisler | 642261a | 2016-11-08 11:34:45 +1100 | [diff] [blame] | 1753 | #endif /* CONFIG_FS_DAX_PMD */ |
Dave Jiang | a2d5816 | 2017-02-24 14:56:59 -0800 | [diff] [blame] | 1754 | |
| 1755 | /** |
| 1756 | * dax_iomap_fault - handle a page fault on a DAX file |
| 1757 | * @vmf: The description of the fault |
Jan Kara | cec04e8 | 2017-11-01 16:36:38 +0100 | [diff] [blame] | 1758 | * @pe_size: Size of the page to fault in |
Jan Kara | 9a0dd42 | 2017-11-01 16:36:39 +0100 | [diff] [blame] | 1759 | * @pfnp: PFN to insert for synchronous faults if fsync is required |
Jan Kara | c0b2462 | 2018-01-07 16:38:43 -0500 | [diff] [blame] | 1760 | * @iomap_errp: Storage for detailed error code in case of error |
Jan Kara | cec04e8 | 2017-11-01 16:36:38 +0100 | [diff] [blame] | 1761 | * @ops: Iomap ops passed from the file system |
Dave Jiang | a2d5816 | 2017-02-24 14:56:59 -0800 | [diff] [blame] | 1762 | * |
| 1763 | * When a page fault occurs, filesystems may call this helper in |
| 1764 | * their fault handler for DAX files. dax_iomap_fault() assumes the caller |
| 1765 | * has done all the necessary locking for page fault to proceed |
| 1766 | * successfully. |
| 1767 | */ |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1768 | vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, |
Jan Kara | c0b2462 | 2018-01-07 16:38:43 -0500 | [diff] [blame] | 1769 | pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) |
Dave Jiang | a2d5816 | 2017-02-24 14:56:59 -0800 | [diff] [blame] | 1770 | { |
Dave Jiang | c791ace | 2017-02-24 14:57:08 -0800 | [diff] [blame] | 1771 | switch (pe_size) { |
| 1772 | case PE_SIZE_PTE: |
Jan Kara | c0b2462 | 2018-01-07 16:38:43 -0500 | [diff] [blame] | 1773 | return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops); |
Dave Jiang | c791ace | 2017-02-24 14:57:08 -0800 | [diff] [blame] | 1774 | case PE_SIZE_PMD: |
Jan Kara | 9a0dd42 | 2017-11-01 16:36:39 +0100 | [diff] [blame] | 1775 | return dax_iomap_pmd_fault(vmf, pfnp, ops); |
Dave Jiang | a2d5816 | 2017-02-24 14:56:59 -0800 | [diff] [blame] | 1776 | default: |
| 1777 | return VM_FAULT_FALLBACK; |
| 1778 | } |
| 1779 | } |
| 1780 | EXPORT_SYMBOL_GPL(dax_iomap_fault); |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1781 | |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1782 | /* |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1783 | * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables |
| 1784 | * @vmf: The description of the fault |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1785 | * @pfn: PFN to insert |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1786 | * @order: Order of entry to insert. |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1787 | * |
Matthew Wilcox | a77d19f | 2018-03-27 13:39:38 -0400 | [diff] [blame] | 1788 | * This function inserts a writeable PTE or PMD entry into the page tables |
| 1789 | * for an mmaped DAX file. It also marks the page cache entry as dirty. |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1790 | */ |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1791 | static vm_fault_t |
| 1792 | dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order) |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1793 | { |
| 1794 | struct address_space *mapping = vmf->vma->vm_file->f_mapping; |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1795 | XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, order); |
| 1796 | void *entry; |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1797 | vm_fault_t ret; |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1798 | |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1799 | xas_lock_irq(&xas); |
| 1800 | entry = get_unlocked_entry(&xas); |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1801 | /* Did we race with someone splitting entry or so? */ |
| 1802 | if (!entry || |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1803 | (order == 0 && !dax_is_pte_entry(entry)) || |
| 1804 | (order == PMD_ORDER && (xa_is_internal(entry) || |
| 1805 | !dax_is_pmd_entry(entry)))) { |
| 1806 | put_unlocked_entry(&xas, entry); |
| 1807 | xas_unlock_irq(&xas); |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1808 | trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, |
| 1809 | VM_FAULT_NOPAGE); |
| 1810 | return VM_FAULT_NOPAGE; |
| 1811 | } |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1812 | xas_set_mark(&xas, PAGECACHE_TAG_DIRTY); |
| 1813 | dax_lock_entry(&xas, entry); |
| 1814 | xas_unlock_irq(&xas); |
| 1815 | if (order == 0) |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1816 | ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1817 | #ifdef CONFIG_FS_DAX_PMD |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1818 | else if (order == PMD_ORDER) |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1819 | ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1820 | pfn, true); |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1821 | #endif |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1822 | else |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1823 | ret = VM_FAULT_FALLBACK; |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1824 | dax_unlock_entry(&xas, entry); |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1825 | trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret); |
| 1826 | return ret; |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1827 | } |
| 1828 | |
| 1829 | /** |
| 1830 | * dax_finish_sync_fault - finish synchronous page fault |
| 1831 | * @vmf: The description of the fault |
| 1832 | * @pe_size: Size of entry to be inserted |
| 1833 | * @pfn: PFN to insert |
| 1834 | * |
| 1835 | * This function ensures that the file range touched by the page fault is |
| 1836 | * stored persistently on the media and handles inserting of appropriate page |
| 1837 | * table entry. |
| 1838 | */ |
Souptick Joarder | ab77dab | 2018-06-07 17:04:29 -0700 | [diff] [blame] | 1839 | vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, |
| 1840 | enum page_entry_size pe_size, pfn_t pfn) |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1841 | { |
| 1842 | int err; |
| 1843 | loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1844 | unsigned int order = pe_order(pe_size); |
| 1845 | size_t len = PAGE_SIZE << order; |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1846 | |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1847 | err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); |
| 1848 | if (err) |
| 1849 | return VM_FAULT_SIGBUS; |
Matthew Wilcox | cfc93c6 | 2018-03-28 11:48:03 -0400 | [diff] [blame] | 1850 | return dax_insert_pfn_mkwrite(vmf, pfn, order); |
Jan Kara | 71eab6d | 2017-11-01 16:36:43 +0100 | [diff] [blame] | 1851 | } |
| 1852 | EXPORT_SYMBOL_GPL(dax_finish_sync_fault); |