12025cf9eSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2d475c634SMatthew Wilcox /* 3d475c634SMatthew Wilcox * fs/dax.c - Direct Access filesystem code 4d475c634SMatthew Wilcox * Copyright (c) 2013-2014 Intel Corporation 5d475c634SMatthew Wilcox * Author: Matthew Wilcox <matthew.r.wilcox@intel.com> 6d475c634SMatthew Wilcox * Author: Ross Zwisler <ross.zwisler@linux.intel.com> 7d475c634SMatthew Wilcox */ 8d475c634SMatthew Wilcox 9d475c634SMatthew Wilcox #include <linux/atomic.h> 10d475c634SMatthew Wilcox #include <linux/blkdev.h> 11d475c634SMatthew Wilcox #include <linux/buffer_head.h> 12d77e92e2SRoss Zwisler #include <linux/dax.h> 13d475c634SMatthew Wilcox #include <linux/fs.h> 14d475c634SMatthew Wilcox #include <linux/genhd.h> 15f7ca90b1SMatthew Wilcox #include <linux/highmem.h> 16f7ca90b1SMatthew Wilcox #include <linux/memcontrol.h> 17f7ca90b1SMatthew Wilcox #include <linux/mm.h> 18d475c634SMatthew Wilcox #include <linux/mutex.h> 199973c98eSRoss Zwisler #include <linux/pagevec.h> 20289c6aedSMatthew Wilcox #include <linux/sched.h> 21f361bf4aSIngo Molnar #include <linux/sched/signal.h> 22d475c634SMatthew Wilcox #include <linux/uio.h> 23f7ca90b1SMatthew Wilcox #include <linux/vmstat.h> 2434c0fd54SDan Williams #include <linux/pfn_t.h> 250e749e54SDan Williams #include <linux/sizes.h> 264b4bb46dSJan Kara #include <linux/mmu_notifier.h> 27a254e568SChristoph Hellwig #include <linux/iomap.h> 2811cf9d86SAneesh Kumar K.V #include <asm/pgalloc.h> 29d475c634SMatthew Wilcox 30282a8e03SRoss Zwisler #define CREATE_TRACE_POINTS 31282a8e03SRoss Zwisler #include <trace/events/fs_dax.h> 32282a8e03SRoss Zwisler 33cfc93c6cSMatthew Wilcox static inline unsigned int pe_order(enum page_entry_size pe_size) 34cfc93c6cSMatthew Wilcox { 35cfc93c6cSMatthew Wilcox if (pe_size == PE_SIZE_PTE) 36cfc93c6cSMatthew Wilcox return PAGE_SHIFT - PAGE_SHIFT; 37cfc93c6cSMatthew Wilcox if (pe_size == PE_SIZE_PMD) 38cfc93c6cSMatthew Wilcox return PMD_SHIFT - PAGE_SHIFT; 39cfc93c6cSMatthew Wilcox if (pe_size == PE_SIZE_PUD) 40cfc93c6cSMatthew Wilcox return PUD_SHIFT - PAGE_SHIFT; 41cfc93c6cSMatthew Wilcox return ~0; 42cfc93c6cSMatthew Wilcox } 43cfc93c6cSMatthew Wilcox 44ac401cc7SJan Kara /* We choose 4096 entries - same as per-zone page wait tables */ 45ac401cc7SJan Kara #define DAX_WAIT_TABLE_BITS 12 46ac401cc7SJan Kara #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) 47ac401cc7SJan Kara 48917f3452SRoss Zwisler /* The 'colour' (ie low bits) within a PMD of a page offset. */ 49917f3452SRoss Zwisler #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) 50977fbdcdSMatthew Wilcox #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) 51917f3452SRoss Zwisler 52cfc93c6cSMatthew Wilcox /* The order of a PMD entry */ 53cfc93c6cSMatthew Wilcox #define PMD_ORDER (PMD_SHIFT - PAGE_SHIFT) 54cfc93c6cSMatthew Wilcox 55ce95ab0fSRoss Zwisler static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; 56ac401cc7SJan Kara 57ac401cc7SJan Kara static int __init init_dax_wait_table(void) 58ac401cc7SJan Kara { 59ac401cc7SJan Kara int i; 60ac401cc7SJan Kara 61ac401cc7SJan Kara for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) 62ac401cc7SJan Kara init_waitqueue_head(wait_table + i); 63ac401cc7SJan Kara return 0; 64ac401cc7SJan Kara } 65ac401cc7SJan Kara fs_initcall(init_dax_wait_table); 66ac401cc7SJan Kara 67527b19d0SRoss Zwisler /* 683159f943SMatthew Wilcox * DAX pagecache entries use XArray value entries so they can't be mistaken 693159f943SMatthew Wilcox * for pages. We use one bit for locking, one bit for the entry size (PMD) 703159f943SMatthew Wilcox * and two more to tell us if the entry is a zero page or an empty entry that 713159f943SMatthew Wilcox * is just used for locking. In total four special bits. 72527b19d0SRoss Zwisler * 73527b19d0SRoss Zwisler * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE 74527b19d0SRoss Zwisler * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem 75527b19d0SRoss Zwisler * block allocation. 76527b19d0SRoss Zwisler */ 773159f943SMatthew Wilcox #define DAX_SHIFT (4) 783159f943SMatthew Wilcox #define DAX_LOCKED (1UL << 0) 793159f943SMatthew Wilcox #define DAX_PMD (1UL << 1) 803159f943SMatthew Wilcox #define DAX_ZERO_PAGE (1UL << 2) 813159f943SMatthew Wilcox #define DAX_EMPTY (1UL << 3) 82527b19d0SRoss Zwisler 83a77d19f4SMatthew Wilcox static unsigned long dax_to_pfn(void *entry) 84527b19d0SRoss Zwisler { 853159f943SMatthew Wilcox return xa_to_value(entry) >> DAX_SHIFT; 86527b19d0SRoss Zwisler } 87527b19d0SRoss Zwisler 889f32d221SMatthew Wilcox static void *dax_make_entry(pfn_t pfn, unsigned long flags) 899f32d221SMatthew Wilcox { 909f32d221SMatthew Wilcox return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT)); 919f32d221SMatthew Wilcox } 929f32d221SMatthew Wilcox 93cfc93c6cSMatthew Wilcox static bool dax_is_locked(void *entry) 94cfc93c6cSMatthew Wilcox { 95cfc93c6cSMatthew Wilcox return xa_to_value(entry) & DAX_LOCKED; 96cfc93c6cSMatthew Wilcox } 97cfc93c6cSMatthew Wilcox 98a77d19f4SMatthew Wilcox static unsigned int dax_entry_order(void *entry) 99527b19d0SRoss Zwisler { 1003159f943SMatthew Wilcox if (xa_to_value(entry) & DAX_PMD) 101cfc93c6cSMatthew Wilcox return PMD_ORDER; 102527b19d0SRoss Zwisler return 0; 103527b19d0SRoss Zwisler } 104527b19d0SRoss Zwisler 105fda490d3SMatthew Wilcox static unsigned long dax_is_pmd_entry(void *entry) 106642261acSRoss Zwisler { 1073159f943SMatthew Wilcox return xa_to_value(entry) & DAX_PMD; 108642261acSRoss Zwisler } 109642261acSRoss Zwisler 110fda490d3SMatthew Wilcox static bool dax_is_pte_entry(void *entry) 111642261acSRoss Zwisler { 1123159f943SMatthew Wilcox return !(xa_to_value(entry) & DAX_PMD); 113642261acSRoss Zwisler } 114642261acSRoss Zwisler 115642261acSRoss Zwisler static int dax_is_zero_entry(void *entry) 116642261acSRoss Zwisler { 1173159f943SMatthew Wilcox return xa_to_value(entry) & DAX_ZERO_PAGE; 118642261acSRoss Zwisler } 119642261acSRoss Zwisler 120642261acSRoss Zwisler static int dax_is_empty_entry(void *entry) 121642261acSRoss Zwisler { 1223159f943SMatthew Wilcox return xa_to_value(entry) & DAX_EMPTY; 123642261acSRoss Zwisler } 124642261acSRoss Zwisler 125f7ca90b1SMatthew Wilcox /* 12623c84eb7SMatthew Wilcox (Oracle) * true if the entry that was found is of a smaller order than the entry 12723c84eb7SMatthew Wilcox (Oracle) * we were looking for 12823c84eb7SMatthew Wilcox (Oracle) */ 12923c84eb7SMatthew Wilcox (Oracle) static bool dax_is_conflict(void *entry) 13023c84eb7SMatthew Wilcox (Oracle) { 13123c84eb7SMatthew Wilcox (Oracle) return entry == XA_RETRY_ENTRY; 13223c84eb7SMatthew Wilcox (Oracle) } 13323c84eb7SMatthew Wilcox (Oracle) 13423c84eb7SMatthew Wilcox (Oracle) /* 135a77d19f4SMatthew Wilcox * DAX page cache entry locking 136ac401cc7SJan Kara */ 137ac401cc7SJan Kara struct exceptional_entry_key { 138ec4907ffSMatthew Wilcox struct xarray *xa; 13963e95b5cSRoss Zwisler pgoff_t entry_start; 140ac401cc7SJan Kara }; 141ac401cc7SJan Kara 142ac401cc7SJan Kara struct wait_exceptional_entry_queue { 143ac6424b9SIngo Molnar wait_queue_entry_t wait; 144ac401cc7SJan Kara struct exceptional_entry_key key; 145ac401cc7SJan Kara }; 146ac401cc7SJan Kara 147698ab77aSVivek Goyal /** 148698ab77aSVivek Goyal * enum dax_wake_mode: waitqueue wakeup behaviour 149698ab77aSVivek Goyal * @WAKE_ALL: wake all waiters in the waitqueue 150698ab77aSVivek Goyal * @WAKE_NEXT: wake only the first waiter in the waitqueue 151698ab77aSVivek Goyal */ 152698ab77aSVivek Goyal enum dax_wake_mode { 153698ab77aSVivek Goyal WAKE_ALL, 154698ab77aSVivek Goyal WAKE_NEXT, 155698ab77aSVivek Goyal }; 156698ab77aSVivek Goyal 157b15cd800SMatthew Wilcox static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas, 158b15cd800SMatthew Wilcox void *entry, struct exceptional_entry_key *key) 15963e95b5cSRoss Zwisler { 16063e95b5cSRoss Zwisler unsigned long hash; 161b15cd800SMatthew Wilcox unsigned long index = xas->xa_index; 16263e95b5cSRoss Zwisler 16363e95b5cSRoss Zwisler /* 16463e95b5cSRoss Zwisler * If 'entry' is a PMD, align the 'index' that we use for the wait 16563e95b5cSRoss Zwisler * queue to the start of that PMD. This ensures that all offsets in 16663e95b5cSRoss Zwisler * the range covered by the PMD map to the same bit lock. 16763e95b5cSRoss Zwisler */ 168642261acSRoss Zwisler if (dax_is_pmd_entry(entry)) 169917f3452SRoss Zwisler index &= ~PG_PMD_COLOUR; 170b15cd800SMatthew Wilcox key->xa = xas->xa; 17163e95b5cSRoss Zwisler key->entry_start = index; 17263e95b5cSRoss Zwisler 173b15cd800SMatthew Wilcox hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS); 17463e95b5cSRoss Zwisler return wait_table + hash; 17563e95b5cSRoss Zwisler } 17663e95b5cSRoss Zwisler 177ec4907ffSMatthew Wilcox static int wake_exceptional_entry_func(wait_queue_entry_t *wait, 178ec4907ffSMatthew Wilcox unsigned int mode, int sync, void *keyp) 179ac401cc7SJan Kara { 180ac401cc7SJan Kara struct exceptional_entry_key *key = keyp; 181ac401cc7SJan Kara struct wait_exceptional_entry_queue *ewait = 182ac401cc7SJan Kara container_of(wait, struct wait_exceptional_entry_queue, wait); 183ac401cc7SJan Kara 184ec4907ffSMatthew Wilcox if (key->xa != ewait->key.xa || 18563e95b5cSRoss Zwisler key->entry_start != ewait->key.entry_start) 186ac401cc7SJan Kara return 0; 187ac401cc7SJan Kara return autoremove_wake_function(wait, mode, sync, NULL); 188ac401cc7SJan Kara } 189ac401cc7SJan Kara 190ac401cc7SJan Kara /* 191b93b0163SMatthew Wilcox * @entry may no longer be the entry at the index in the mapping. 192b93b0163SMatthew Wilcox * The important information it's conveying is whether the entry at 193b93b0163SMatthew Wilcox * this index used to be a PMD entry. 194e30331ffSRoss Zwisler */ 195698ab77aSVivek Goyal static void dax_wake_entry(struct xa_state *xas, void *entry, 196698ab77aSVivek Goyal enum dax_wake_mode mode) 197e30331ffSRoss Zwisler { 198e30331ffSRoss Zwisler struct exceptional_entry_key key; 199e30331ffSRoss Zwisler wait_queue_head_t *wq; 200e30331ffSRoss Zwisler 201b15cd800SMatthew Wilcox wq = dax_entry_waitqueue(xas, entry, &key); 202e30331ffSRoss Zwisler 203e30331ffSRoss Zwisler /* 204e30331ffSRoss Zwisler * Checking for locked entry and prepare_to_wait_exclusive() happens 205b93b0163SMatthew Wilcox * under the i_pages lock, ditto for entry handling in our callers. 206e30331ffSRoss Zwisler * So at this point all tasks that could have seen our entry locked 207e30331ffSRoss Zwisler * must be in the waitqueue and the following check will see them. 208e30331ffSRoss Zwisler */ 209e30331ffSRoss Zwisler if (waitqueue_active(wq)) 210698ab77aSVivek Goyal __wake_up(wq, TASK_NORMAL, mode == WAKE_ALL ? 0 : 1, &key); 211e30331ffSRoss Zwisler } 212e30331ffSRoss Zwisler 213cfc93c6cSMatthew Wilcox /* 214cfc93c6cSMatthew Wilcox * Look up entry in page cache, wait for it to become unlocked if it 215cfc93c6cSMatthew Wilcox * is a DAX entry and return it. The caller must subsequently call 216cfc93c6cSMatthew Wilcox * put_unlocked_entry() if it did not lock the entry or dax_unlock_entry() 21723c84eb7SMatthew Wilcox (Oracle) * if it did. The entry returned may have a larger order than @order. 21823c84eb7SMatthew Wilcox (Oracle) * If @order is larger than the order of the entry found in i_pages, this 21923c84eb7SMatthew Wilcox (Oracle) * function returns a dax_is_conflict entry. 220cfc93c6cSMatthew Wilcox * 221cfc93c6cSMatthew Wilcox * Must be called with the i_pages lock held. 222cfc93c6cSMatthew Wilcox */ 22323c84eb7SMatthew Wilcox (Oracle) static void *get_unlocked_entry(struct xa_state *xas, unsigned int order) 224cfc93c6cSMatthew Wilcox { 225cfc93c6cSMatthew Wilcox void *entry; 226cfc93c6cSMatthew Wilcox struct wait_exceptional_entry_queue ewait; 227cfc93c6cSMatthew Wilcox wait_queue_head_t *wq; 228cfc93c6cSMatthew Wilcox 229cfc93c6cSMatthew Wilcox init_wait(&ewait.wait); 230cfc93c6cSMatthew Wilcox ewait.wait.func = wake_exceptional_entry_func; 231cfc93c6cSMatthew Wilcox 232cfc93c6cSMatthew Wilcox for (;;) { 2330e40de03SMatthew Wilcox entry = xas_find_conflict(xas); 2346370740eSDan Williams if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) 2356370740eSDan Williams return entry; 23623c84eb7SMatthew Wilcox (Oracle) if (dax_entry_order(entry) < order) 23723c84eb7SMatthew Wilcox (Oracle) return XA_RETRY_ENTRY; 2386370740eSDan Williams if (!dax_is_locked(entry)) 239cfc93c6cSMatthew Wilcox return entry; 240cfc93c6cSMatthew Wilcox 241b15cd800SMatthew Wilcox wq = dax_entry_waitqueue(xas, entry, &ewait.key); 242cfc93c6cSMatthew Wilcox prepare_to_wait_exclusive(wq, &ewait.wait, 243cfc93c6cSMatthew Wilcox TASK_UNINTERRUPTIBLE); 244cfc93c6cSMatthew Wilcox xas_unlock_irq(xas); 245cfc93c6cSMatthew Wilcox xas_reset(xas); 246cfc93c6cSMatthew Wilcox schedule(); 247cfc93c6cSMatthew Wilcox finish_wait(wq, &ewait.wait); 248cfc93c6cSMatthew Wilcox xas_lock_irq(xas); 249cfc93c6cSMatthew Wilcox } 250cfc93c6cSMatthew Wilcox } 251cfc93c6cSMatthew Wilcox 25255e56f06SMatthew Wilcox /* 25355e56f06SMatthew Wilcox * The only thing keeping the address space around is the i_pages lock 25455e56f06SMatthew Wilcox * (it's cycled in clear_inode() after removing the entries from i_pages) 25555e56f06SMatthew Wilcox * After we call xas_unlock_irq(), we cannot touch xas->xa. 25655e56f06SMatthew Wilcox */ 25755e56f06SMatthew Wilcox static void wait_entry_unlocked(struct xa_state *xas, void *entry) 25855e56f06SMatthew Wilcox { 25955e56f06SMatthew Wilcox struct wait_exceptional_entry_queue ewait; 26055e56f06SMatthew Wilcox wait_queue_head_t *wq; 26155e56f06SMatthew Wilcox 26255e56f06SMatthew Wilcox init_wait(&ewait.wait); 26355e56f06SMatthew Wilcox ewait.wait.func = wake_exceptional_entry_func; 26455e56f06SMatthew Wilcox 26555e56f06SMatthew Wilcox wq = dax_entry_waitqueue(xas, entry, &ewait.key); 266d8a70641SDan Williams /* 267d8a70641SDan Williams * Unlike get_unlocked_entry() there is no guarantee that this 268d8a70641SDan Williams * path ever successfully retrieves an unlocked entry before an 269d8a70641SDan Williams * inode dies. Perform a non-exclusive wait in case this path 270d8a70641SDan Williams * never successfully performs its own wake up. 271d8a70641SDan Williams */ 272d8a70641SDan Williams prepare_to_wait(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); 27355e56f06SMatthew Wilcox xas_unlock_irq(xas); 27455e56f06SMatthew Wilcox schedule(); 27555e56f06SMatthew Wilcox finish_wait(wq, &ewait.wait); 27655e56f06SMatthew Wilcox } 27755e56f06SMatthew Wilcox 2784c3d043dSVivek Goyal static void put_unlocked_entry(struct xa_state *xas, void *entry, 2794c3d043dSVivek Goyal enum dax_wake_mode mode) 280cfc93c6cSMatthew Wilcox { 28161c30c98SJan Kara if (entry && !dax_is_conflict(entry)) 2824c3d043dSVivek Goyal dax_wake_entry(xas, entry, mode); 283cfc93c6cSMatthew Wilcox } 284cfc93c6cSMatthew Wilcox 285cfc93c6cSMatthew Wilcox /* 286cfc93c6cSMatthew Wilcox * We used the xa_state to get the entry, but then we locked the entry and 287cfc93c6cSMatthew Wilcox * dropped the xa_lock, so we know the xa_state is stale and must be reset 288cfc93c6cSMatthew Wilcox * before use. 289cfc93c6cSMatthew Wilcox */ 290cfc93c6cSMatthew Wilcox static void dax_unlock_entry(struct xa_state *xas, void *entry) 291cfc93c6cSMatthew Wilcox { 292cfc93c6cSMatthew Wilcox void *old; 293cfc93c6cSMatthew Wilcox 2947ae2ea7dSMatthew Wilcox BUG_ON(dax_is_locked(entry)); 295cfc93c6cSMatthew Wilcox xas_reset(xas); 296cfc93c6cSMatthew Wilcox xas_lock_irq(xas); 297cfc93c6cSMatthew Wilcox old = xas_store(xas, entry); 298cfc93c6cSMatthew Wilcox xas_unlock_irq(xas); 299cfc93c6cSMatthew Wilcox BUG_ON(!dax_is_locked(old)); 300698ab77aSVivek Goyal dax_wake_entry(xas, entry, WAKE_NEXT); 301cfc93c6cSMatthew Wilcox } 302cfc93c6cSMatthew Wilcox 303cfc93c6cSMatthew Wilcox /* 304cfc93c6cSMatthew Wilcox * Return: The entry stored at this location before it was locked. 305cfc93c6cSMatthew Wilcox */ 306cfc93c6cSMatthew Wilcox static void *dax_lock_entry(struct xa_state *xas, void *entry) 307cfc93c6cSMatthew Wilcox { 308cfc93c6cSMatthew Wilcox unsigned long v = xa_to_value(entry); 309cfc93c6cSMatthew Wilcox return xas_store(xas, xa_mk_value(v | DAX_LOCKED)); 310cfc93c6cSMatthew Wilcox } 311cfc93c6cSMatthew Wilcox 312d2c997c0SDan Williams static unsigned long dax_entry_size(void *entry) 313d2c997c0SDan Williams { 314d2c997c0SDan Williams if (dax_is_zero_entry(entry)) 315d2c997c0SDan Williams return 0; 316d2c997c0SDan Williams else if (dax_is_empty_entry(entry)) 317d2c997c0SDan Williams return 0; 318d2c997c0SDan Williams else if (dax_is_pmd_entry(entry)) 319d2c997c0SDan Williams return PMD_SIZE; 320d2c997c0SDan Williams else 321d2c997c0SDan Williams return PAGE_SIZE; 322d2c997c0SDan Williams } 323d2c997c0SDan Williams 324a77d19f4SMatthew Wilcox static unsigned long dax_end_pfn(void *entry) 325d2c997c0SDan Williams { 326a77d19f4SMatthew Wilcox return dax_to_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE; 327d2c997c0SDan Williams } 328d2c997c0SDan Williams 329d2c997c0SDan Williams /* 330d2c997c0SDan Williams * Iterate through all mapped pfns represented by an entry, i.e. skip 331d2c997c0SDan Williams * 'empty' and 'zero' entries. 332d2c997c0SDan Williams */ 333d2c997c0SDan Williams #define for_each_mapped_pfn(entry, pfn) \ 334a77d19f4SMatthew Wilcox for (pfn = dax_to_pfn(entry); \ 335a77d19f4SMatthew Wilcox pfn < dax_end_pfn(entry); pfn++) 336d2c997c0SDan Williams 33773449dafSDan Williams /* 33873449dafSDan Williams * TODO: for reflink+dax we need a way to associate a single page with 33973449dafSDan Williams * multiple address_space instances at different linear_page_index() 34073449dafSDan Williams * offsets. 34173449dafSDan Williams */ 34273449dafSDan Williams static void dax_associate_entry(void *entry, struct address_space *mapping, 34373449dafSDan Williams struct vm_area_struct *vma, unsigned long address) 344d2c997c0SDan Williams { 34573449dafSDan Williams unsigned long size = dax_entry_size(entry), pfn, index; 34673449dafSDan Williams int i = 0; 347d2c997c0SDan Williams 348d2c997c0SDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 349d2c997c0SDan Williams return; 350d2c997c0SDan Williams 35173449dafSDan Williams index = linear_page_index(vma, address & ~(size - 1)); 352d2c997c0SDan Williams for_each_mapped_pfn(entry, pfn) { 353d2c997c0SDan Williams struct page *page = pfn_to_page(pfn); 354d2c997c0SDan Williams 355d2c997c0SDan Williams WARN_ON_ONCE(page->mapping); 356d2c997c0SDan Williams page->mapping = mapping; 35773449dafSDan Williams page->index = index + i++; 358d2c997c0SDan Williams } 359d2c997c0SDan Williams } 360d2c997c0SDan Williams 361d2c997c0SDan Williams static void dax_disassociate_entry(void *entry, struct address_space *mapping, 362d2c997c0SDan Williams bool trunc) 363d2c997c0SDan Williams { 364d2c997c0SDan Williams unsigned long pfn; 365d2c997c0SDan Williams 366d2c997c0SDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 367d2c997c0SDan Williams return; 368d2c997c0SDan Williams 369d2c997c0SDan Williams for_each_mapped_pfn(entry, pfn) { 370d2c997c0SDan Williams struct page *page = pfn_to_page(pfn); 371d2c997c0SDan Williams 372d2c997c0SDan Williams WARN_ON_ONCE(trunc && page_ref_count(page) > 1); 373d2c997c0SDan Williams WARN_ON_ONCE(page->mapping && page->mapping != mapping); 374d2c997c0SDan Williams page->mapping = NULL; 37573449dafSDan Williams page->index = 0; 376d2c997c0SDan Williams } 377d2c997c0SDan Williams } 378d2c997c0SDan Williams 3795fac7408SDan Williams static struct page *dax_busy_page(void *entry) 3805fac7408SDan Williams { 3815fac7408SDan Williams unsigned long pfn; 3825fac7408SDan Williams 3835fac7408SDan Williams for_each_mapped_pfn(entry, pfn) { 3845fac7408SDan Williams struct page *page = pfn_to_page(pfn); 3855fac7408SDan Williams 3865fac7408SDan Williams if (page_ref_count(page) > 1) 3875fac7408SDan Williams return page; 3885fac7408SDan Williams } 3895fac7408SDan Williams return NULL; 3905fac7408SDan Williams } 3915fac7408SDan Williams 392c5bbd451SMatthew Wilcox /* 393c5bbd451SMatthew Wilcox * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page 394c5bbd451SMatthew Wilcox * @page: The page whose entry we want to lock 395c5bbd451SMatthew Wilcox * 396c5bbd451SMatthew Wilcox * Context: Process context. 39727359fd6SMatthew Wilcox * Return: A cookie to pass to dax_unlock_page() or 0 if the entry could 39827359fd6SMatthew Wilcox * not be locked. 399c5bbd451SMatthew Wilcox */ 40027359fd6SMatthew Wilcox dax_entry_t dax_lock_page(struct page *page) 401c2a7d2a1SDan Williams { 4029f32d221SMatthew Wilcox XA_STATE(xas, NULL, 0); 4039f32d221SMatthew Wilcox void *entry; 404c2a7d2a1SDan Williams 405c5bbd451SMatthew Wilcox /* Ensure page->mapping isn't freed while we look at it */ 406c5bbd451SMatthew Wilcox rcu_read_lock(); 407c2a7d2a1SDan Williams for (;;) { 4089f32d221SMatthew Wilcox struct address_space *mapping = READ_ONCE(page->mapping); 409c2a7d2a1SDan Williams 41027359fd6SMatthew Wilcox entry = NULL; 411c93db7bbSMatthew Wilcox if (!mapping || !dax_mapping(mapping)) 412c5bbd451SMatthew Wilcox break; 413c2a7d2a1SDan Williams 414c2a7d2a1SDan Williams /* 415c2a7d2a1SDan Williams * In the device-dax case there's no need to lock, a 416c2a7d2a1SDan Williams * struct dev_pagemap pin is sufficient to keep the 417c2a7d2a1SDan Williams * inode alive, and we assume we have dev_pagemap pin 418c2a7d2a1SDan Williams * otherwise we would not have a valid pfn_to_page() 419c2a7d2a1SDan Williams * translation. 420c2a7d2a1SDan Williams */ 42127359fd6SMatthew Wilcox entry = (void *)~0UL; 4229f32d221SMatthew Wilcox if (S_ISCHR(mapping->host->i_mode)) 423c5bbd451SMatthew Wilcox break; 424c2a7d2a1SDan Williams 4259f32d221SMatthew Wilcox xas.xa = &mapping->i_pages; 4269f32d221SMatthew Wilcox xas_lock_irq(&xas); 427c2a7d2a1SDan Williams if (mapping != page->mapping) { 4289f32d221SMatthew Wilcox xas_unlock_irq(&xas); 429c2a7d2a1SDan Williams continue; 430c2a7d2a1SDan Williams } 4319f32d221SMatthew Wilcox xas_set(&xas, page->index); 4329f32d221SMatthew Wilcox entry = xas_load(&xas); 4339f32d221SMatthew Wilcox if (dax_is_locked(entry)) { 434c5bbd451SMatthew Wilcox rcu_read_unlock(); 43555e56f06SMatthew Wilcox wait_entry_unlocked(&xas, entry); 436c5bbd451SMatthew Wilcox rcu_read_lock(); 437c2a7d2a1SDan Williams continue; 438c2a7d2a1SDan Williams } 4399f32d221SMatthew Wilcox dax_lock_entry(&xas, entry); 4409f32d221SMatthew Wilcox xas_unlock_irq(&xas); 441c5bbd451SMatthew Wilcox break; 4429f32d221SMatthew Wilcox } 443c5bbd451SMatthew Wilcox rcu_read_unlock(); 44427359fd6SMatthew Wilcox return (dax_entry_t)entry; 445c2a7d2a1SDan Williams } 446c2a7d2a1SDan Williams 44727359fd6SMatthew Wilcox void dax_unlock_page(struct page *page, dax_entry_t cookie) 448c2a7d2a1SDan Williams { 449c2a7d2a1SDan Williams struct address_space *mapping = page->mapping; 4509f32d221SMatthew Wilcox XA_STATE(xas, &mapping->i_pages, page->index); 451c2a7d2a1SDan Williams 4529f32d221SMatthew Wilcox if (S_ISCHR(mapping->host->i_mode)) 453c2a7d2a1SDan Williams return; 454c2a7d2a1SDan Williams 45527359fd6SMatthew Wilcox dax_unlock_entry(&xas, (void *)cookie); 456c2a7d2a1SDan Williams } 457c2a7d2a1SDan Williams 458ac401cc7SJan Kara /* 459a77d19f4SMatthew Wilcox * Find page cache entry at given index. If it is a DAX entry, return it 460a77d19f4SMatthew Wilcox * with the entry locked. If the page cache doesn't contain an entry at 461a77d19f4SMatthew Wilcox * that index, add a locked empty entry. 462ac401cc7SJan Kara * 4633159f943SMatthew Wilcox * When requesting an entry with size DAX_PMD, grab_mapping_entry() will 464b15cd800SMatthew Wilcox * either return that locked entry or will return VM_FAULT_FALLBACK. 465b15cd800SMatthew Wilcox * This will happen if there are any PTE entries within the PMD range 466b15cd800SMatthew Wilcox * that we are requesting. 467642261acSRoss Zwisler * 468b15cd800SMatthew Wilcox * We always favor PTE entries over PMD entries. There isn't a flow where we 469b15cd800SMatthew Wilcox * evict PTE entries in order to 'upgrade' them to a PMD entry. A PMD 470b15cd800SMatthew Wilcox * insertion will fail if it finds any PTE entries already in the tree, and a 471b15cd800SMatthew Wilcox * PTE insertion will cause an existing PMD entry to be unmapped and 472b15cd800SMatthew Wilcox * downgraded to PTE entries. This happens for both PMD zero pages as 473b15cd800SMatthew Wilcox * well as PMD empty entries. 474642261acSRoss Zwisler * 475b15cd800SMatthew Wilcox * The exception to this downgrade path is for PMD entries that have 476b15cd800SMatthew Wilcox * real storage backing them. We will leave these real PMD entries in 477b15cd800SMatthew Wilcox * the tree, and PTE writes will simply dirty the entire PMD entry. 478642261acSRoss Zwisler * 479ac401cc7SJan Kara * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For 480ac401cc7SJan Kara * persistent memory the benefit is doubtful. We can add that later if we can 481ac401cc7SJan Kara * show it helps. 482b15cd800SMatthew Wilcox * 483b15cd800SMatthew Wilcox * On error, this function does not return an ERR_PTR. Instead it returns 484b15cd800SMatthew Wilcox * a VM_FAULT code, encoded as an xarray internal entry. The ERR_PTR values 485b15cd800SMatthew Wilcox * overlap with xarray value entries. 486ac401cc7SJan Kara */ 487b15cd800SMatthew Wilcox static void *grab_mapping_entry(struct xa_state *xas, 48823c84eb7SMatthew Wilcox (Oracle) struct address_space *mapping, unsigned int order) 489ac401cc7SJan Kara { 490b15cd800SMatthew Wilcox unsigned long index = xas->xa_index; 4911a14e377SJan Kara bool pmd_downgrade; /* splitting PMD entry into PTE entries? */ 492b15cd800SMatthew Wilcox void *entry; 493ac401cc7SJan Kara 494b15cd800SMatthew Wilcox retry: 4951a14e377SJan Kara pmd_downgrade = false; 496b15cd800SMatthew Wilcox xas_lock_irq(xas); 49723c84eb7SMatthew Wilcox (Oracle) entry = get_unlocked_entry(xas, order); 498642261acSRoss Zwisler 499b15cd800SMatthew Wilcox if (entry) { 50023c84eb7SMatthew Wilcox (Oracle) if (dax_is_conflict(entry)) 50123c84eb7SMatthew Wilcox (Oracle) goto fallback; 5020e40de03SMatthew Wilcox if (!xa_is_value(entry)) { 50349688e65SHao Li xas_set_err(xas, -EIO); 50491d25ba8SRoss Zwisler goto out_unlock; 50591d25ba8SRoss Zwisler } 50691d25ba8SRoss Zwisler 50723c84eb7SMatthew Wilcox (Oracle) if (order == 0) { 50891d25ba8SRoss Zwisler if (dax_is_pmd_entry(entry) && 509642261acSRoss Zwisler (dax_is_zero_entry(entry) || 510642261acSRoss Zwisler dax_is_empty_entry(entry))) { 511642261acSRoss Zwisler pmd_downgrade = true; 512642261acSRoss Zwisler } 513642261acSRoss Zwisler } 514642261acSRoss Zwisler } 515642261acSRoss Zwisler 516642261acSRoss Zwisler if (pmd_downgrade) { 517642261acSRoss Zwisler /* 518642261acSRoss Zwisler * Make sure 'entry' remains valid while we drop 519b93b0163SMatthew Wilcox * the i_pages lock. 520642261acSRoss Zwisler */ 521b15cd800SMatthew Wilcox dax_lock_entry(xas, entry); 522642261acSRoss Zwisler 523642261acSRoss Zwisler /* 524642261acSRoss Zwisler * Besides huge zero pages the only other thing that gets 525642261acSRoss Zwisler * downgraded are empty entries which don't need to be 526642261acSRoss Zwisler * unmapped. 527642261acSRoss Zwisler */ 528b15cd800SMatthew Wilcox if (dax_is_zero_entry(entry)) { 529b15cd800SMatthew Wilcox xas_unlock_irq(xas); 530b15cd800SMatthew Wilcox unmap_mapping_pages(mapping, 531b15cd800SMatthew Wilcox xas->xa_index & ~PG_PMD_COLOUR, 532977fbdcdSMatthew Wilcox PG_PMD_NR, false); 533b15cd800SMatthew Wilcox xas_reset(xas); 534b15cd800SMatthew Wilcox xas_lock_irq(xas); 535e11f8b7bSRoss Zwisler } 536e11f8b7bSRoss Zwisler 537d2c997c0SDan Williams dax_disassociate_entry(entry, mapping, false); 538b15cd800SMatthew Wilcox xas_store(xas, NULL); /* undo the PMD join */ 539698ab77aSVivek Goyal dax_wake_entry(xas, entry, WAKE_ALL); 5407f0e07fbSMatthew Wilcox (Oracle) mapping->nrpages -= PG_PMD_NR; 541b15cd800SMatthew Wilcox entry = NULL; 542b15cd800SMatthew Wilcox xas_set(xas, index); 543642261acSRoss Zwisler } 544642261acSRoss Zwisler 545b15cd800SMatthew Wilcox if (entry) { 546b15cd800SMatthew Wilcox dax_lock_entry(xas, entry); 547b15cd800SMatthew Wilcox } else { 54823c84eb7SMatthew Wilcox (Oracle) unsigned long flags = DAX_EMPTY; 54923c84eb7SMatthew Wilcox (Oracle) 55023c84eb7SMatthew Wilcox (Oracle) if (order > 0) 55123c84eb7SMatthew Wilcox (Oracle) flags |= DAX_PMD; 55223c84eb7SMatthew Wilcox (Oracle) entry = dax_make_entry(pfn_to_pfn_t(0), flags); 553b15cd800SMatthew Wilcox dax_lock_entry(xas, entry); 554b15cd800SMatthew Wilcox if (xas_error(xas)) 555b15cd800SMatthew Wilcox goto out_unlock; 5567f0e07fbSMatthew Wilcox (Oracle) mapping->nrpages += 1UL << order; 557ac401cc7SJan Kara } 558b15cd800SMatthew Wilcox 559642261acSRoss Zwisler out_unlock: 560b15cd800SMatthew Wilcox xas_unlock_irq(xas); 561b15cd800SMatthew Wilcox if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM)) 562b15cd800SMatthew Wilcox goto retry; 563b15cd800SMatthew Wilcox if (xas->xa_node == XA_ERROR(-ENOMEM)) 564b15cd800SMatthew Wilcox return xa_mk_internal(VM_FAULT_OOM); 565b15cd800SMatthew Wilcox if (xas_error(xas)) 566b15cd800SMatthew Wilcox return xa_mk_internal(VM_FAULT_SIGBUS); 567e3ad61c6SRoss Zwisler return entry; 568b15cd800SMatthew Wilcox fallback: 569b15cd800SMatthew Wilcox xas_unlock_irq(xas); 570b15cd800SMatthew Wilcox return xa_mk_internal(VM_FAULT_FALLBACK); 571ac401cc7SJan Kara } 572ac401cc7SJan Kara 5735fac7408SDan Williams /** 5746bbdd563SVivek Goyal * dax_layout_busy_page_range - find first pinned page in @mapping 5755fac7408SDan Williams * @mapping: address space to scan for a page with ref count > 1 5766bbdd563SVivek Goyal * @start: Starting offset. Page containing 'start' is included. 5776bbdd563SVivek Goyal * @end: End offset. Page containing 'end' is included. If 'end' is LLONG_MAX, 5786bbdd563SVivek Goyal * pages from 'start' till the end of file are included. 5795fac7408SDan Williams * 5805fac7408SDan Williams * DAX requires ZONE_DEVICE mapped pages. These pages are never 5815fac7408SDan Williams * 'onlined' to the page allocator so they are considered idle when 5825fac7408SDan Williams * page->count == 1. A filesystem uses this interface to determine if 5835fac7408SDan Williams * any page in the mapping is busy, i.e. for DMA, or other 5845fac7408SDan Williams * get_user_pages() usages. 5855fac7408SDan Williams * 5865fac7408SDan Williams * It is expected that the filesystem is holding locks to block the 5875fac7408SDan Williams * establishment of new mappings in this address_space. I.e. it expects 5885fac7408SDan Williams * to be able to run unmap_mapping_range() and subsequently not race 5895fac7408SDan Williams * mapping_mapped() becoming true. 5905fac7408SDan Williams */ 5916bbdd563SVivek Goyal struct page *dax_layout_busy_page_range(struct address_space *mapping, 5926bbdd563SVivek Goyal loff_t start, loff_t end) 5935fac7408SDan Williams { 594084a8990SMatthew Wilcox void *entry; 595084a8990SMatthew Wilcox unsigned int scanned = 0; 5965fac7408SDan Williams struct page *page = NULL; 5976bbdd563SVivek Goyal pgoff_t start_idx = start >> PAGE_SHIFT; 5986bbdd563SVivek Goyal pgoff_t end_idx; 5996bbdd563SVivek Goyal XA_STATE(xas, &mapping->i_pages, start_idx); 6005fac7408SDan Williams 6015fac7408SDan Williams /* 6025fac7408SDan Williams * In the 'limited' case get_user_pages() for dax is disabled. 6035fac7408SDan Williams */ 6045fac7408SDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 6055fac7408SDan Williams return NULL; 6065fac7408SDan Williams 6075fac7408SDan Williams if (!dax_mapping(mapping) || !mapping_mapped(mapping)) 6085fac7408SDan Williams return NULL; 6095fac7408SDan Williams 6106bbdd563SVivek Goyal /* If end == LLONG_MAX, all pages from start to till end of file */ 6116bbdd563SVivek Goyal if (end == LLONG_MAX) 6126bbdd563SVivek Goyal end_idx = ULONG_MAX; 6136bbdd563SVivek Goyal else 6146bbdd563SVivek Goyal end_idx = end >> PAGE_SHIFT; 6155fac7408SDan Williams /* 6165fac7408SDan Williams * If we race get_user_pages_fast() here either we'll see the 617084a8990SMatthew Wilcox * elevated page count in the iteration and wait, or 6185fac7408SDan Williams * get_user_pages_fast() will see that the page it took a reference 6195fac7408SDan Williams * against is no longer mapped in the page tables and bail to the 6205fac7408SDan Williams * get_user_pages() slow path. The slow path is protected by 6215fac7408SDan Williams * pte_lock() and pmd_lock(). New references are not taken without 6226bbdd563SVivek Goyal * holding those locks, and unmap_mapping_pages() will not zero the 6235fac7408SDan Williams * pte or pmd without holding the respective lock, so we are 6245fac7408SDan Williams * guaranteed to either see new references or prevent new 6255fac7408SDan Williams * references from being established. 6265fac7408SDan Williams */ 6276bbdd563SVivek Goyal unmap_mapping_pages(mapping, start_idx, end_idx - start_idx + 1, 0); 6285fac7408SDan Williams 629084a8990SMatthew Wilcox xas_lock_irq(&xas); 6306bbdd563SVivek Goyal xas_for_each(&xas, entry, end_idx) { 631084a8990SMatthew Wilcox if (WARN_ON_ONCE(!xa_is_value(entry))) 6325fac7408SDan Williams continue; 633084a8990SMatthew Wilcox if (unlikely(dax_is_locked(entry))) 63423c84eb7SMatthew Wilcox (Oracle) entry = get_unlocked_entry(&xas, 0); 6355fac7408SDan Williams if (entry) 6365fac7408SDan Williams page = dax_busy_page(entry); 6374c3d043dSVivek Goyal put_unlocked_entry(&xas, entry, WAKE_NEXT); 6385fac7408SDan Williams if (page) 6395fac7408SDan Williams break; 640084a8990SMatthew Wilcox if (++scanned % XA_CHECK_SCHED) 641084a8990SMatthew Wilcox continue; 642cdbf8897SRoss Zwisler 643084a8990SMatthew Wilcox xas_pause(&xas); 644084a8990SMatthew Wilcox xas_unlock_irq(&xas); 645084a8990SMatthew Wilcox cond_resched(); 646084a8990SMatthew Wilcox xas_lock_irq(&xas); 6475fac7408SDan Williams } 648084a8990SMatthew Wilcox xas_unlock_irq(&xas); 6495fac7408SDan Williams return page; 6505fac7408SDan Williams } 6516bbdd563SVivek Goyal EXPORT_SYMBOL_GPL(dax_layout_busy_page_range); 6526bbdd563SVivek Goyal 6536bbdd563SVivek Goyal struct page *dax_layout_busy_page(struct address_space *mapping) 6546bbdd563SVivek Goyal { 6556bbdd563SVivek Goyal return dax_layout_busy_page_range(mapping, 0, LLONG_MAX); 6566bbdd563SVivek Goyal } 6575fac7408SDan Williams EXPORT_SYMBOL_GPL(dax_layout_busy_page); 6585fac7408SDan Williams 659a77d19f4SMatthew Wilcox static int __dax_invalidate_entry(struct address_space *mapping, 660c6dcf52cSJan Kara pgoff_t index, bool trunc) 661c6dcf52cSJan Kara { 66207f2d89cSMatthew Wilcox XA_STATE(xas, &mapping->i_pages, index); 663c6dcf52cSJan Kara int ret = 0; 664c6dcf52cSJan Kara void *entry; 665c6dcf52cSJan Kara 66607f2d89cSMatthew Wilcox xas_lock_irq(&xas); 66723c84eb7SMatthew Wilcox (Oracle) entry = get_unlocked_entry(&xas, 0); 6683159f943SMatthew Wilcox if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) 669c6dcf52cSJan Kara goto out; 670c6dcf52cSJan Kara if (!trunc && 67107f2d89cSMatthew Wilcox (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) || 67207f2d89cSMatthew Wilcox xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE))) 673c6dcf52cSJan Kara goto out; 674d2c997c0SDan Williams dax_disassociate_entry(entry, mapping, trunc); 67507f2d89cSMatthew Wilcox xas_store(&xas, NULL); 6767f0e07fbSMatthew Wilcox (Oracle) mapping->nrpages -= 1UL << dax_entry_order(entry); 677c6dcf52cSJan Kara ret = 1; 678c6dcf52cSJan Kara out: 67923738832SVivek Goyal put_unlocked_entry(&xas, entry, WAKE_ALL); 68007f2d89cSMatthew Wilcox xas_unlock_irq(&xas); 681c6dcf52cSJan Kara return ret; 682c6dcf52cSJan Kara } 68307f2d89cSMatthew Wilcox 684ac401cc7SJan Kara /* 6853159f943SMatthew Wilcox * Delete DAX entry at @index from @mapping. Wait for it 6863159f943SMatthew Wilcox * to be unlocked before deleting it. 687ac401cc7SJan Kara */ 688ac401cc7SJan Kara int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) 689ac401cc7SJan Kara { 690a77d19f4SMatthew Wilcox int ret = __dax_invalidate_entry(mapping, index, true); 691ac401cc7SJan Kara 692ac401cc7SJan Kara /* 693ac401cc7SJan Kara * This gets called from truncate / punch_hole path. As such, the caller 694ac401cc7SJan Kara * must hold locks protecting against concurrent modifications of the 695a77d19f4SMatthew Wilcox * page cache (usually fs-private i_mmap_sem for writing). Since the 6963159f943SMatthew Wilcox * caller has seen a DAX entry for this index, we better find it 697ac401cc7SJan Kara * at that index as well... 698ac401cc7SJan Kara */ 699c6dcf52cSJan Kara WARN_ON_ONCE(!ret); 700c6dcf52cSJan Kara return ret; 701ac401cc7SJan Kara } 702ac401cc7SJan Kara 703c6dcf52cSJan Kara /* 7043159f943SMatthew Wilcox * Invalidate DAX entry if it is clean. 705c6dcf52cSJan Kara */ 706c6dcf52cSJan Kara int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 707c6dcf52cSJan Kara pgoff_t index) 708c6dcf52cSJan Kara { 709a77d19f4SMatthew Wilcox return __dax_invalidate_entry(mapping, index, false); 710ac401cc7SJan Kara } 711ac401cc7SJan Kara 712c7fe193fSIra Weiny static int copy_cow_page_dax(struct block_device *bdev, struct dax_device *dax_dev, 713c7fe193fSIra Weiny sector_t sector, struct page *to, unsigned long vaddr) 714f7ca90b1SMatthew Wilcox { 715cccbce67SDan Williams void *vto, *kaddr; 716cccbce67SDan Williams pgoff_t pgoff; 717cccbce67SDan Williams long rc; 718cccbce67SDan Williams int id; 719e2e05394SRoss Zwisler 720c7fe193fSIra Weiny rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff); 721cccbce67SDan Williams if (rc) 722cccbce67SDan Williams return rc; 723cccbce67SDan Williams 724cccbce67SDan Williams id = dax_read_lock(); 725c7fe193fSIra Weiny rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(PAGE_SIZE), &kaddr, NULL); 726cccbce67SDan Williams if (rc < 0) { 727cccbce67SDan Williams dax_read_unlock(id); 728cccbce67SDan Williams return rc; 729cccbce67SDan Williams } 730f7ca90b1SMatthew Wilcox vto = kmap_atomic(to); 731cccbce67SDan Williams copy_user_page(vto, (void __force *)kaddr, vaddr, to); 732f7ca90b1SMatthew Wilcox kunmap_atomic(vto); 733cccbce67SDan Williams dax_read_unlock(id); 734f7ca90b1SMatthew Wilcox return 0; 735f7ca90b1SMatthew Wilcox } 736f7ca90b1SMatthew Wilcox 737642261acSRoss Zwisler /* 738642261acSRoss Zwisler * By this point grab_mapping_entry() has ensured that we have a locked entry 739642261acSRoss Zwisler * of the appropriate size so we don't have to worry about downgrading PMDs to 740642261acSRoss Zwisler * PTEs. If we happen to be trying to insert a PTE and there is a PMD 741642261acSRoss Zwisler * already in the tree, we will skip the insertion and just dirty the PMD as 742642261acSRoss Zwisler * appropriate. 743642261acSRoss Zwisler */ 744b15cd800SMatthew Wilcox static void *dax_insert_entry(struct xa_state *xas, 745b15cd800SMatthew Wilcox struct address_space *mapping, struct vm_fault *vmf, 746b15cd800SMatthew Wilcox void *entry, pfn_t pfn, unsigned long flags, bool dirty) 7479973c98eSRoss Zwisler { 748b15cd800SMatthew Wilcox void *new_entry = dax_make_entry(pfn, flags); 7499973c98eSRoss Zwisler 750f5b7b748SJan Kara if (dirty) 7519973c98eSRoss Zwisler __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); 7529973c98eSRoss Zwisler 7533159f943SMatthew Wilcox if (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE)) { 754b15cd800SMatthew Wilcox unsigned long index = xas->xa_index; 75591d25ba8SRoss Zwisler /* we are replacing a zero page with block mapping */ 75691d25ba8SRoss Zwisler if (dax_is_pmd_entry(entry)) 757977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, 758977fbdcdSMatthew Wilcox PG_PMD_NR, false); 75991d25ba8SRoss Zwisler else /* pte entry */ 760b15cd800SMatthew Wilcox unmap_mapping_pages(mapping, index, 1, false); 761ac401cc7SJan Kara } 7629973c98eSRoss Zwisler 763b15cd800SMatthew Wilcox xas_reset(xas); 764b15cd800SMatthew Wilcox xas_lock_irq(xas); 7651571c029SJan Kara if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { 7661571c029SJan Kara void *old; 7671571c029SJan Kara 768d2c997c0SDan Williams dax_disassociate_entry(entry, mapping, false); 76973449dafSDan Williams dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address); 770642261acSRoss Zwisler /* 771a77d19f4SMatthew Wilcox * Only swap our new entry into the page cache if the current 772642261acSRoss Zwisler * entry is a zero page or an empty entry. If a normal PTE or 773a77d19f4SMatthew Wilcox * PMD entry is already in the cache, we leave it alone. This 774642261acSRoss Zwisler * means that if we are trying to insert a PTE and the 775642261acSRoss Zwisler * existing entry is a PMD, we will just leave the PMD in the 776642261acSRoss Zwisler * tree and dirty it if necessary. 777642261acSRoss Zwisler */ 7781571c029SJan Kara old = dax_lock_entry(xas, new_entry); 779b15cd800SMatthew Wilcox WARN_ON_ONCE(old != xa_mk_value(xa_to_value(entry) | 780b15cd800SMatthew Wilcox DAX_LOCKED)); 78191d25ba8SRoss Zwisler entry = new_entry; 782b15cd800SMatthew Wilcox } else { 783b15cd800SMatthew Wilcox xas_load(xas); /* Walk the xa_state */ 784ac401cc7SJan Kara } 78591d25ba8SRoss Zwisler 786f5b7b748SJan Kara if (dirty) 787b15cd800SMatthew Wilcox xas_set_mark(xas, PAGECACHE_TAG_DIRTY); 78891d25ba8SRoss Zwisler 789b15cd800SMatthew Wilcox xas_unlock_irq(xas); 79091d25ba8SRoss Zwisler return entry; 7919973c98eSRoss Zwisler } 7929973c98eSRoss Zwisler 793a77d19f4SMatthew Wilcox static inline 794a77d19f4SMatthew Wilcox unsigned long pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) 7954b4bb46dSJan Kara { 7964b4bb46dSJan Kara unsigned long address; 7974b4bb46dSJan Kara 7984b4bb46dSJan Kara address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); 7994b4bb46dSJan Kara VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); 8004b4bb46dSJan Kara return address; 8014b4bb46dSJan Kara } 8024b4bb46dSJan Kara 8034b4bb46dSJan Kara /* Walk all mappings of a given index of a file and writeprotect them */ 804a77d19f4SMatthew Wilcox static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index, 805a77d19f4SMatthew Wilcox unsigned long pfn) 8064b4bb46dSJan Kara { 8074b4bb46dSJan Kara struct vm_area_struct *vma; 808f729c8c9SRoss Zwisler pte_t pte, *ptep = NULL; 809f729c8c9SRoss Zwisler pmd_t *pmdp = NULL; 8104b4bb46dSJan Kara spinlock_t *ptl; 8114b4bb46dSJan Kara 8124b4bb46dSJan Kara i_mmap_lock_read(mapping); 8134b4bb46dSJan Kara vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { 814ac46d4f3SJérôme Glisse struct mmu_notifier_range range; 815ac46d4f3SJérôme Glisse unsigned long address; 8164b4bb46dSJan Kara 8174b4bb46dSJan Kara cond_resched(); 8184b4bb46dSJan Kara 8194b4bb46dSJan Kara if (!(vma->vm_flags & VM_SHARED)) 8204b4bb46dSJan Kara continue; 8214b4bb46dSJan Kara 8224b4bb46dSJan Kara address = pgoff_address(index, vma); 823a4d1a885SJérôme Glisse 824a4d1a885SJérôme Glisse /* 8259fd6dad1SPaolo Bonzini * follow_invalidate_pte() will use the range to call 826ff5c19edSChristoph Hellwig * mmu_notifier_invalidate_range_start() on our behalf before 827ff5c19edSChristoph Hellwig * taking any lock. 828a4d1a885SJérôme Glisse */ 8299fd6dad1SPaolo Bonzini if (follow_invalidate_pte(vma->vm_mm, address, &range, &ptep, 8309fd6dad1SPaolo Bonzini &pmdp, &ptl)) 8314b4bb46dSJan Kara continue; 832f729c8c9SRoss Zwisler 8330f10851eSJérôme Glisse /* 8340f10851eSJérôme Glisse * No need to call mmu_notifier_invalidate_range() as we are 8350f10851eSJérôme Glisse * downgrading page table protection not changing it to point 8360f10851eSJérôme Glisse * to a new page. 8370f10851eSJérôme Glisse * 838ad56b738SMike Rapoport * See Documentation/vm/mmu_notifier.rst 8390f10851eSJérôme Glisse */ 840f729c8c9SRoss Zwisler if (pmdp) { 841f729c8c9SRoss Zwisler #ifdef CONFIG_FS_DAX_PMD 842f729c8c9SRoss Zwisler pmd_t pmd; 843f729c8c9SRoss Zwisler 844f729c8c9SRoss Zwisler if (pfn != pmd_pfn(*pmdp)) 845f729c8c9SRoss Zwisler goto unlock_pmd; 846f6f37321SLinus Torvalds if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) 847f729c8c9SRoss Zwisler goto unlock_pmd; 848f729c8c9SRoss Zwisler 849f729c8c9SRoss Zwisler flush_cache_page(vma, address, pfn); 850024eee0eSAneesh Kumar K.V pmd = pmdp_invalidate(vma, address, pmdp); 851f729c8c9SRoss Zwisler pmd = pmd_wrprotect(pmd); 852f729c8c9SRoss Zwisler pmd = pmd_mkclean(pmd); 853f729c8c9SRoss Zwisler set_pmd_at(vma->vm_mm, address, pmdp, pmd); 854f729c8c9SRoss Zwisler unlock_pmd: 855f729c8c9SRoss Zwisler #endif 856ee190ca6SJan H. Schönherr spin_unlock(ptl); 857f729c8c9SRoss Zwisler } else { 8584b4bb46dSJan Kara if (pfn != pte_pfn(*ptep)) 859f729c8c9SRoss Zwisler goto unlock_pte; 8604b4bb46dSJan Kara if (!pte_dirty(*ptep) && !pte_write(*ptep)) 861f729c8c9SRoss Zwisler goto unlock_pte; 8624b4bb46dSJan Kara 8634b4bb46dSJan Kara flush_cache_page(vma, address, pfn); 8644b4bb46dSJan Kara pte = ptep_clear_flush(vma, address, ptep); 8654b4bb46dSJan Kara pte = pte_wrprotect(pte); 8664b4bb46dSJan Kara pte = pte_mkclean(pte); 8674b4bb46dSJan Kara set_pte_at(vma->vm_mm, address, ptep, pte); 868f729c8c9SRoss Zwisler unlock_pte: 8694b4bb46dSJan Kara pte_unmap_unlock(ptep, ptl); 870f729c8c9SRoss Zwisler } 8714b4bb46dSJan Kara 872ac46d4f3SJérôme Glisse mmu_notifier_invalidate_range_end(&range); 8734b4bb46dSJan Kara } 8744b4bb46dSJan Kara i_mmap_unlock_read(mapping); 8754b4bb46dSJan Kara } 8764b4bb46dSJan Kara 8779fc747f6SMatthew Wilcox static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev, 8789fc747f6SMatthew Wilcox struct address_space *mapping, void *entry) 8799973c98eSRoss Zwisler { 880e4b3448bSMatthew Wilcox unsigned long pfn, index, count; 8813fe0791cSDan Williams long ret = 0; 8829973c98eSRoss Zwisler 8839973c98eSRoss Zwisler /* 884a6abc2c0SJan Kara * A page got tagged dirty in DAX mapping? Something is seriously 885a6abc2c0SJan Kara * wrong. 8869973c98eSRoss Zwisler */ 8873159f943SMatthew Wilcox if (WARN_ON(!xa_is_value(entry))) 888a6abc2c0SJan Kara return -EIO; 8899973c98eSRoss Zwisler 8909fc747f6SMatthew Wilcox if (unlikely(dax_is_locked(entry))) { 8919fc747f6SMatthew Wilcox void *old_entry = entry; 8929fc747f6SMatthew Wilcox 89323c84eb7SMatthew Wilcox (Oracle) entry = get_unlocked_entry(xas, 0); 8949fc747f6SMatthew Wilcox 895a6abc2c0SJan Kara /* Entry got punched out / reallocated? */ 8969fc747f6SMatthew Wilcox if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) 897a6abc2c0SJan Kara goto put_unlocked; 898a6abc2c0SJan Kara /* 8999fc747f6SMatthew Wilcox * Entry got reallocated elsewhere? No need to writeback. 9009fc747f6SMatthew Wilcox * We have to compare pfns as we must not bail out due to 9019fc747f6SMatthew Wilcox * difference in lockbit or entry type. 902a6abc2c0SJan Kara */ 9039fc747f6SMatthew Wilcox if (dax_to_pfn(old_entry) != dax_to_pfn(entry)) 904a6abc2c0SJan Kara goto put_unlocked; 905642261acSRoss Zwisler if (WARN_ON_ONCE(dax_is_empty_entry(entry) || 906642261acSRoss Zwisler dax_is_zero_entry(entry))) { 9079973c98eSRoss Zwisler ret = -EIO; 908a6abc2c0SJan Kara goto put_unlocked; 9099973c98eSRoss Zwisler } 9109973c98eSRoss Zwisler 9119fc747f6SMatthew Wilcox /* Another fsync thread may have already done this entry */ 9129fc747f6SMatthew Wilcox if (!xas_get_mark(xas, PAGECACHE_TAG_TOWRITE)) 913a6abc2c0SJan Kara goto put_unlocked; 9149fc747f6SMatthew Wilcox } 9159fc747f6SMatthew Wilcox 916a6abc2c0SJan Kara /* Lock the entry to serialize with page faults */ 9179fc747f6SMatthew Wilcox dax_lock_entry(xas, entry); 9189fc747f6SMatthew Wilcox 919a6abc2c0SJan Kara /* 920a6abc2c0SJan Kara * We can clear the tag now but we have to be careful so that concurrent 921a6abc2c0SJan Kara * dax_writeback_one() calls for the same index cannot finish before we 922a6abc2c0SJan Kara * actually flush the caches. This is achieved as the calls will look 923b93b0163SMatthew Wilcox * at the entry only under the i_pages lock and once they do that 924b93b0163SMatthew Wilcox * they will see the entry locked and wait for it to unlock. 925a6abc2c0SJan Kara */ 9269fc747f6SMatthew Wilcox xas_clear_mark(xas, PAGECACHE_TAG_TOWRITE); 9279fc747f6SMatthew Wilcox xas_unlock_irq(xas); 928a6abc2c0SJan Kara 929642261acSRoss Zwisler /* 930e4b3448bSMatthew Wilcox * If dax_writeback_mapping_range() was given a wbc->range_start 931e4b3448bSMatthew Wilcox * in the middle of a PMD, the 'index' we use needs to be 932e4b3448bSMatthew Wilcox * aligned to the start of the PMD. 9333fe0791cSDan Williams * This allows us to flush for PMD_SIZE and not have to worry about 9343fe0791cSDan Williams * partial PMD writebacks. 935642261acSRoss Zwisler */ 936a77d19f4SMatthew Wilcox pfn = dax_to_pfn(entry); 937e4b3448bSMatthew Wilcox count = 1UL << dax_entry_order(entry); 938e4b3448bSMatthew Wilcox index = xas->xa_index & ~(count - 1); 939cccbce67SDan Williams 940e4b3448bSMatthew Wilcox dax_entry_mkclean(mapping, index, pfn); 941e4b3448bSMatthew Wilcox dax_flush(dax_dev, page_address(pfn_to_page(pfn)), count * PAGE_SIZE); 9424b4bb46dSJan Kara /* 9434b4bb46dSJan Kara * After we have flushed the cache, we can clear the dirty tag. There 9444b4bb46dSJan Kara * cannot be new dirty data in the pfn after the flush has completed as 9454b4bb46dSJan Kara * the pfn mappings are writeprotected and fault waits for mapping 9464b4bb46dSJan Kara * entry lock. 9474b4bb46dSJan Kara */ 9489fc747f6SMatthew Wilcox xas_reset(xas); 9499fc747f6SMatthew Wilcox xas_lock_irq(xas); 9509fc747f6SMatthew Wilcox xas_store(xas, entry); 9519fc747f6SMatthew Wilcox xas_clear_mark(xas, PAGECACHE_TAG_DIRTY); 952698ab77aSVivek Goyal dax_wake_entry(xas, entry, WAKE_NEXT); 9539fc747f6SMatthew Wilcox 954e4b3448bSMatthew Wilcox trace_dax_writeback_one(mapping->host, index, count); 9559973c98eSRoss Zwisler return ret; 9569973c98eSRoss Zwisler 957a6abc2c0SJan Kara put_unlocked: 9584c3d043dSVivek Goyal put_unlocked_entry(xas, entry, WAKE_NEXT); 9599973c98eSRoss Zwisler return ret; 9609973c98eSRoss Zwisler } 9619973c98eSRoss Zwisler 9629973c98eSRoss Zwisler /* 9639973c98eSRoss Zwisler * Flush the mapping to the persistent domain within the byte range of [start, 9649973c98eSRoss Zwisler * end]. This is required by data integrity operations to ensure file data is 9659973c98eSRoss Zwisler * on persistent storage prior to completion of the operation. 9669973c98eSRoss Zwisler */ 9677f6d5b52SRoss Zwisler int dax_writeback_mapping_range(struct address_space *mapping, 9683f666c56SVivek Goyal struct dax_device *dax_dev, struct writeback_control *wbc) 9699973c98eSRoss Zwisler { 9709fc747f6SMatthew Wilcox XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT); 9719973c98eSRoss Zwisler struct inode *inode = mapping->host; 9729fc747f6SMatthew Wilcox pgoff_t end_index = wbc->range_end >> PAGE_SHIFT; 9739fc747f6SMatthew Wilcox void *entry; 9749fc747f6SMatthew Wilcox int ret = 0; 9759fc747f6SMatthew Wilcox unsigned int scanned = 0; 9769973c98eSRoss Zwisler 9779973c98eSRoss Zwisler if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) 9789973c98eSRoss Zwisler return -EIO; 9799973c98eSRoss Zwisler 9807716506aSMatthew Wilcox (Oracle) if (mapping_empty(mapping) || wbc->sync_mode != WB_SYNC_ALL) 9817f6d5b52SRoss Zwisler return 0; 9827f6d5b52SRoss Zwisler 9839fc747f6SMatthew Wilcox trace_dax_writeback_range(inode, xas.xa_index, end_index); 9849973c98eSRoss Zwisler 9859fc747f6SMatthew Wilcox tag_pages_for_writeback(mapping, xas.xa_index, end_index); 986d14a3f48SRoss Zwisler 9879fc747f6SMatthew Wilcox xas_lock_irq(&xas); 9889fc747f6SMatthew Wilcox xas_for_each_marked(&xas, entry, end_index, PAGECACHE_TAG_TOWRITE) { 9899fc747f6SMatthew Wilcox ret = dax_writeback_one(&xas, dax_dev, mapping, entry); 990819ec6b9SJeff Layton if (ret < 0) { 991819ec6b9SJeff Layton mapping_set_error(mapping, ret); 9929fc747f6SMatthew Wilcox break; 993d14a3f48SRoss Zwisler } 9949fc747f6SMatthew Wilcox if (++scanned % XA_CHECK_SCHED) 9959fc747f6SMatthew Wilcox continue; 9969fc747f6SMatthew Wilcox 9979fc747f6SMatthew Wilcox xas_pause(&xas); 9989fc747f6SMatthew Wilcox xas_unlock_irq(&xas); 9999fc747f6SMatthew Wilcox cond_resched(); 10009fc747f6SMatthew Wilcox xas_lock_irq(&xas); 1001d14a3f48SRoss Zwisler } 10029fc747f6SMatthew Wilcox xas_unlock_irq(&xas); 10039fc747f6SMatthew Wilcox trace_dax_writeback_range_done(inode, xas.xa_index, end_index); 10049fc747f6SMatthew Wilcox return ret; 10059973c98eSRoss Zwisler } 10069973c98eSRoss Zwisler EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); 10079973c98eSRoss Zwisler 10087e4f4b2dSChristoph Hellwig static sector_t dax_iomap_sector(const struct iomap *iomap, loff_t pos) 1009f7ca90b1SMatthew Wilcox { 1010a3841f94SLinus Torvalds return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9; 101131a6f1a6SJan Kara } 1012f7ca90b1SMatthew Wilcox 10135e161e40SJan Kara static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size, 10145e161e40SJan Kara pfn_t *pfnp) 10155e161e40SJan Kara { 10165e161e40SJan Kara const sector_t sector = dax_iomap_sector(iomap, pos); 10175e161e40SJan Kara pgoff_t pgoff; 10185e161e40SJan Kara int id, rc; 10195e161e40SJan Kara long length; 10205e161e40SJan Kara 10215e161e40SJan Kara rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff); 1022cccbce67SDan Williams if (rc) 1023cccbce67SDan Williams return rc; 1024cccbce67SDan Williams id = dax_read_lock(); 10255e161e40SJan Kara length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), 102686ed913bSHuaisheng Ye NULL, pfnp); 10275e161e40SJan Kara if (length < 0) { 10285e161e40SJan Kara rc = length; 10295e161e40SJan Kara goto out; 10305e161e40SJan Kara } 10315e161e40SJan Kara rc = -EINVAL; 10325e161e40SJan Kara if (PFN_PHYS(length) < size) 10335e161e40SJan Kara goto out; 10345e161e40SJan Kara if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) 10355e161e40SJan Kara goto out; 10365e161e40SJan Kara /* For larger pages we need devmap */ 10375e161e40SJan Kara if (length > 1 && !pfn_t_devmap(*pfnp)) 10385e161e40SJan Kara goto out; 10395e161e40SJan Kara rc = 0; 10405e161e40SJan Kara out: 1041cccbce67SDan Williams dax_read_unlock(id); 1042cccbce67SDan Williams return rc; 1043cccbce67SDan Williams } 1044f7ca90b1SMatthew Wilcox 10452f89dc12SJan Kara /* 104691d25ba8SRoss Zwisler * The user has performed a load from a hole in the file. Allocating a new 104791d25ba8SRoss Zwisler * page in the file would cause excessive storage usage for workloads with 104891d25ba8SRoss Zwisler * sparse files. Instead we insert a read-only mapping of the 4k zero page. 104991d25ba8SRoss Zwisler * If this page is ever written to we will re-fault and change the mapping to 105091d25ba8SRoss Zwisler * point to real DAX storage instead. 10512f89dc12SJan Kara */ 1052b15cd800SMatthew Wilcox static vm_fault_t dax_load_hole(struct xa_state *xas, 1053b15cd800SMatthew Wilcox struct address_space *mapping, void **entry, 1054e30331ffSRoss Zwisler struct vm_fault *vmf) 1055e30331ffSRoss Zwisler { 1056e30331ffSRoss Zwisler struct inode *inode = mapping->host; 105791d25ba8SRoss Zwisler unsigned long vaddr = vmf->address; 1058b90ca5ccSMatthew Wilcox pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr)); 1059b90ca5ccSMatthew Wilcox vm_fault_t ret; 1060e30331ffSRoss Zwisler 1061b15cd800SMatthew Wilcox *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, 10623159f943SMatthew Wilcox DAX_ZERO_PAGE, false); 10633159f943SMatthew Wilcox 1064ab77dab4SSouptick Joarder ret = vmf_insert_mixed(vmf->vma, vaddr, pfn); 1065e30331ffSRoss Zwisler trace_dax_load_hole(inode, vmf, ret); 1066e30331ffSRoss Zwisler return ret; 1067e30331ffSRoss Zwisler } 1068e30331ffSRoss Zwisler 1069*c2436190SShiyang Ruan #ifdef CONFIG_FS_DAX_PMD 1070*c2436190SShiyang Ruan static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, 1071*c2436190SShiyang Ruan struct iomap *iomap, void **entry) 1072*c2436190SShiyang Ruan { 1073*c2436190SShiyang Ruan struct address_space *mapping = vmf->vma->vm_file->f_mapping; 1074*c2436190SShiyang Ruan unsigned long pmd_addr = vmf->address & PMD_MASK; 1075*c2436190SShiyang Ruan struct vm_area_struct *vma = vmf->vma; 1076*c2436190SShiyang Ruan struct inode *inode = mapping->host; 1077*c2436190SShiyang Ruan pgtable_t pgtable = NULL; 1078*c2436190SShiyang Ruan struct page *zero_page; 1079*c2436190SShiyang Ruan spinlock_t *ptl; 1080*c2436190SShiyang Ruan pmd_t pmd_entry; 1081*c2436190SShiyang Ruan pfn_t pfn; 1082*c2436190SShiyang Ruan 1083*c2436190SShiyang Ruan zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); 1084*c2436190SShiyang Ruan 1085*c2436190SShiyang Ruan if (unlikely(!zero_page)) 1086*c2436190SShiyang Ruan goto fallback; 1087*c2436190SShiyang Ruan 1088*c2436190SShiyang Ruan pfn = page_to_pfn_t(zero_page); 1089*c2436190SShiyang Ruan *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, 1090*c2436190SShiyang Ruan DAX_PMD | DAX_ZERO_PAGE, false); 1091*c2436190SShiyang Ruan 1092*c2436190SShiyang Ruan if (arch_needs_pgtable_deposit()) { 1093*c2436190SShiyang Ruan pgtable = pte_alloc_one(vma->vm_mm); 1094*c2436190SShiyang Ruan if (!pgtable) 1095*c2436190SShiyang Ruan return VM_FAULT_OOM; 1096*c2436190SShiyang Ruan } 1097*c2436190SShiyang Ruan 1098*c2436190SShiyang Ruan ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1099*c2436190SShiyang Ruan if (!pmd_none(*(vmf->pmd))) { 1100*c2436190SShiyang Ruan spin_unlock(ptl); 1101*c2436190SShiyang Ruan goto fallback; 1102*c2436190SShiyang Ruan } 1103*c2436190SShiyang Ruan 1104*c2436190SShiyang Ruan if (pgtable) { 1105*c2436190SShiyang Ruan pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); 1106*c2436190SShiyang Ruan mm_inc_nr_ptes(vma->vm_mm); 1107*c2436190SShiyang Ruan } 1108*c2436190SShiyang Ruan pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); 1109*c2436190SShiyang Ruan pmd_entry = pmd_mkhuge(pmd_entry); 1110*c2436190SShiyang Ruan set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); 1111*c2436190SShiyang Ruan spin_unlock(ptl); 1112*c2436190SShiyang Ruan trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry); 1113*c2436190SShiyang Ruan return VM_FAULT_NOPAGE; 1114*c2436190SShiyang Ruan 1115*c2436190SShiyang Ruan fallback: 1116*c2436190SShiyang Ruan if (pgtable) 1117*c2436190SShiyang Ruan pte_free(vma->vm_mm, pgtable); 1118*c2436190SShiyang Ruan trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry); 1119*c2436190SShiyang Ruan return VM_FAULT_FALLBACK; 1120*c2436190SShiyang Ruan } 1121*c2436190SShiyang Ruan #else 1122*c2436190SShiyang Ruan static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, 1123*c2436190SShiyang Ruan struct iomap *iomap, void **entry) 1124*c2436190SShiyang Ruan { 1125*c2436190SShiyang Ruan return VM_FAULT_FALLBACK; 1126*c2436190SShiyang Ruan } 1127*c2436190SShiyang Ruan #endif /* CONFIG_FS_DAX_PMD */ 1128*c2436190SShiyang Ruan 112981ee8e52SMatthew Wilcox (Oracle) s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap) 1130679c8bd3SChristoph Hellwig { 11314f3b4f16SVivek Goyal sector_t sector = iomap_sector(iomap, pos & PAGE_MASK); 1132cccbce67SDan Williams pgoff_t pgoff; 1133cccbce67SDan Williams long rc, id; 1134cccbce67SDan Williams void *kaddr; 11350a23f9ffSVivek Goyal bool page_aligned = false; 113681ee8e52SMatthew Wilcox (Oracle) unsigned offset = offset_in_page(pos); 113781ee8e52SMatthew Wilcox (Oracle) unsigned size = min_t(u64, PAGE_SIZE - offset, length); 11380a23f9ffSVivek Goyal 11390a23f9ffSVivek Goyal if (IS_ALIGNED(sector << SECTOR_SHIFT, PAGE_SIZE) && 114081ee8e52SMatthew Wilcox (Oracle) (size == PAGE_SIZE)) 11410a23f9ffSVivek Goyal page_aligned = true; 1142cccbce67SDan Williams 11434f3b4f16SVivek Goyal rc = bdev_dax_pgoff(iomap->bdev, sector, PAGE_SIZE, &pgoff); 1144cccbce67SDan Williams if (rc) 1145cccbce67SDan Williams return rc; 1146cccbce67SDan Williams 1147cccbce67SDan Williams id = dax_read_lock(); 11480a23f9ffSVivek Goyal 11490a23f9ffSVivek Goyal if (page_aligned) 115081ee8e52SMatthew Wilcox (Oracle) rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1); 11510a23f9ffSVivek Goyal else 11524f3b4f16SVivek Goyal rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &kaddr, NULL); 1153cccbce67SDan Williams if (rc < 0) { 1154cccbce67SDan Williams dax_read_unlock(id); 1155cccbce67SDan Williams return rc; 1156cccbce67SDan Williams } 11570a23f9ffSVivek Goyal 11580a23f9ffSVivek Goyal if (!page_aligned) { 115981f55870SDan Williams memset(kaddr + offset, 0, size); 11604f3b4f16SVivek Goyal dax_flush(iomap->dax_dev, kaddr + offset, size); 11614b0228faSVishal Verma } 11620a23f9ffSVivek Goyal dax_read_unlock(id); 116381ee8e52SMatthew Wilcox (Oracle) return size; 1164679c8bd3SChristoph Hellwig } 1165679c8bd3SChristoph Hellwig 1166ca289e0bSChristoph Hellwig static loff_t dax_iomap_iter(const struct iomap_iter *iomi, 1167ca289e0bSChristoph Hellwig struct iov_iter *iter) 1168a254e568SChristoph Hellwig { 1169ca289e0bSChristoph Hellwig const struct iomap *iomap = &iomi->iomap; 1170ca289e0bSChristoph Hellwig loff_t length = iomap_length(iomi); 1171ca289e0bSChristoph Hellwig loff_t pos = iomi->pos; 1172cccbce67SDan Williams struct block_device *bdev = iomap->bdev; 1173cccbce67SDan Williams struct dax_device *dax_dev = iomap->dax_dev; 1174a254e568SChristoph Hellwig loff_t end = pos + length, done = 0; 1175a254e568SChristoph Hellwig ssize_t ret = 0; 1176a77d4786SDan Williams size_t xfer; 1177cccbce67SDan Williams int id; 1178a254e568SChristoph Hellwig 1179a254e568SChristoph Hellwig if (iov_iter_rw(iter) == READ) { 1180ca289e0bSChristoph Hellwig end = min(end, i_size_read(iomi->inode)); 1181a254e568SChristoph Hellwig if (pos >= end) 1182a254e568SChristoph Hellwig return 0; 1183a254e568SChristoph Hellwig 1184a254e568SChristoph Hellwig if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) 1185a254e568SChristoph Hellwig return iov_iter_zero(min(length, end - pos), iter); 1186a254e568SChristoph Hellwig } 1187a254e568SChristoph Hellwig 1188a254e568SChristoph Hellwig if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) 1189a254e568SChristoph Hellwig return -EIO; 1190a254e568SChristoph Hellwig 1191e3fce68cSJan Kara /* 1192e3fce68cSJan Kara * Write can allocate block for an area which has a hole page mapped 1193e3fce68cSJan Kara * into page tables. We have to tear down these mappings so that data 1194e3fce68cSJan Kara * written by write(2) is visible in mmap. 1195e3fce68cSJan Kara */ 1196cd656375SJan Kara if (iomap->flags & IOMAP_F_NEW) { 1197ca289e0bSChristoph Hellwig invalidate_inode_pages2_range(iomi->inode->i_mapping, 1198e3fce68cSJan Kara pos >> PAGE_SHIFT, 1199e3fce68cSJan Kara (end - 1) >> PAGE_SHIFT); 1200e3fce68cSJan Kara } 1201e3fce68cSJan Kara 1202cccbce67SDan Williams id = dax_read_lock(); 1203a254e568SChristoph Hellwig while (pos < end) { 1204a254e568SChristoph Hellwig unsigned offset = pos & (PAGE_SIZE - 1); 1205cccbce67SDan Williams const size_t size = ALIGN(length + offset, PAGE_SIZE); 1206cccbce67SDan Williams const sector_t sector = dax_iomap_sector(iomap, pos); 1207a254e568SChristoph Hellwig ssize_t map_len; 1208cccbce67SDan Williams pgoff_t pgoff; 1209cccbce67SDan Williams void *kaddr; 1210a254e568SChristoph Hellwig 1211d1908f52SMichal Hocko if (fatal_signal_pending(current)) { 1212d1908f52SMichal Hocko ret = -EINTR; 1213d1908f52SMichal Hocko break; 1214d1908f52SMichal Hocko } 1215d1908f52SMichal Hocko 1216cccbce67SDan Williams ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); 1217cccbce67SDan Williams if (ret) 1218cccbce67SDan Williams break; 1219cccbce67SDan Williams 1220cccbce67SDan Williams map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), 122186ed913bSHuaisheng Ye &kaddr, NULL); 1222a254e568SChristoph Hellwig if (map_len < 0) { 1223a254e568SChristoph Hellwig ret = map_len; 1224a254e568SChristoph Hellwig break; 1225a254e568SChristoph Hellwig } 1226a254e568SChristoph Hellwig 1227cccbce67SDan Williams map_len = PFN_PHYS(map_len); 1228cccbce67SDan Williams kaddr += offset; 1229a254e568SChristoph Hellwig map_len -= offset; 1230a254e568SChristoph Hellwig if (map_len > end - pos) 1231a254e568SChristoph Hellwig map_len = end - pos; 1232a254e568SChristoph Hellwig 1233a2e050f5SRoss Zwisler /* 1234a2e050f5SRoss Zwisler * The userspace address for the memory copy has already been 1235a2e050f5SRoss Zwisler * validated via access_ok() in either vfs_read() or 1236a2e050f5SRoss Zwisler * vfs_write(), depending on which operation we are doing. 1237a2e050f5SRoss Zwisler */ 1238a254e568SChristoph Hellwig if (iov_iter_rw(iter) == WRITE) 1239a77d4786SDan Williams xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr, 1240fec53774SDan Williams map_len, iter); 1241a254e568SChristoph Hellwig else 1242a77d4786SDan Williams xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr, 1243b3a9a0c3SDan Williams map_len, iter); 1244a254e568SChristoph Hellwig 1245a77d4786SDan Williams pos += xfer; 1246a77d4786SDan Williams length -= xfer; 1247a77d4786SDan Williams done += xfer; 1248a77d4786SDan Williams 1249a77d4786SDan Williams if (xfer == 0) 1250a77d4786SDan Williams ret = -EFAULT; 1251a77d4786SDan Williams if (xfer < map_len) 1252a77d4786SDan Williams break; 1253a254e568SChristoph Hellwig } 1254cccbce67SDan Williams dax_read_unlock(id); 1255a254e568SChristoph Hellwig 1256a254e568SChristoph Hellwig return done ? done : ret; 1257a254e568SChristoph Hellwig } 1258a254e568SChristoph Hellwig 1259a254e568SChristoph Hellwig /** 126011c59c92SRoss Zwisler * dax_iomap_rw - Perform I/O to a DAX file 1261a254e568SChristoph Hellwig * @iocb: The control block for this I/O 1262a254e568SChristoph Hellwig * @iter: The addresses to do I/O from or to 1263a254e568SChristoph Hellwig * @ops: iomap ops passed from the file system 1264a254e568SChristoph Hellwig * 1265a254e568SChristoph Hellwig * This function performs read and write operations to directly mapped 1266a254e568SChristoph Hellwig * persistent memory. The callers needs to take care of read/write exclusion 1267a254e568SChristoph Hellwig * and evicting any page cache pages in the region under I/O. 1268a254e568SChristoph Hellwig */ 1269a254e568SChristoph Hellwig ssize_t 127011c59c92SRoss Zwisler dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 12718ff6daa1SChristoph Hellwig const struct iomap_ops *ops) 1272a254e568SChristoph Hellwig { 1273ca289e0bSChristoph Hellwig struct iomap_iter iomi = { 1274ca289e0bSChristoph Hellwig .inode = iocb->ki_filp->f_mapping->host, 1275ca289e0bSChristoph Hellwig .pos = iocb->ki_pos, 1276ca289e0bSChristoph Hellwig .len = iov_iter_count(iter), 1277ca289e0bSChristoph Hellwig }; 1278ca289e0bSChristoph Hellwig loff_t done = 0; 1279ca289e0bSChristoph Hellwig int ret; 1280a254e568SChristoph Hellwig 1281168316dbSChristoph Hellwig if (iov_iter_rw(iter) == WRITE) { 1282ca289e0bSChristoph Hellwig lockdep_assert_held_write(&iomi.inode->i_rwsem); 1283ca289e0bSChristoph Hellwig iomi.flags |= IOMAP_WRITE; 1284168316dbSChristoph Hellwig } else { 1285ca289e0bSChristoph Hellwig lockdep_assert_held(&iomi.inode->i_rwsem); 1286168316dbSChristoph Hellwig } 1287a254e568SChristoph Hellwig 128896222d53SJeff Moyer if (iocb->ki_flags & IOCB_NOWAIT) 1289ca289e0bSChristoph Hellwig iomi.flags |= IOMAP_NOWAIT; 129096222d53SJeff Moyer 1291ca289e0bSChristoph Hellwig while ((ret = iomap_iter(&iomi, ops)) > 0) 1292ca289e0bSChristoph Hellwig iomi.processed = dax_iomap_iter(&iomi, iter); 1293a254e568SChristoph Hellwig 1294ca289e0bSChristoph Hellwig done = iomi.pos - iocb->ki_pos; 1295ca289e0bSChristoph Hellwig iocb->ki_pos = iomi.pos; 1296a254e568SChristoph Hellwig return done ? done : ret; 1297a254e568SChristoph Hellwig } 129811c59c92SRoss Zwisler EXPORT_SYMBOL_GPL(dax_iomap_rw); 1299a7d73fe6SChristoph Hellwig 1300ab77dab4SSouptick Joarder static vm_fault_t dax_fault_return(int error) 13019f141d6eSJan Kara { 13029f141d6eSJan Kara if (error == 0) 13039f141d6eSJan Kara return VM_FAULT_NOPAGE; 1304c9aed74eSSouptick Joarder return vmf_error(error); 13059f141d6eSJan Kara } 13069f141d6eSJan Kara 1307aaa422c4SDan Williams /* 1308aaa422c4SDan Williams * MAP_SYNC on a dax mapping guarantees dirty metadata is 1309aaa422c4SDan Williams * flushed on write-faults (non-cow), but not read-faults. 1310aaa422c4SDan Williams */ 1311aaa422c4SDan Williams static bool dax_fault_is_synchronous(unsigned long flags, 1312aaa422c4SDan Williams struct vm_area_struct *vma, struct iomap *iomap) 1313aaa422c4SDan Williams { 1314aaa422c4SDan Williams return (flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) 1315aaa422c4SDan Williams && (iomap->flags & IOMAP_F_DIRTY); 1316aaa422c4SDan Williams } 1317aaa422c4SDan Williams 131855f81639SShiyang Ruan /* 131955f81639SShiyang Ruan * When handling a synchronous page fault and the inode need a fsync, we can 132055f81639SShiyang Ruan * insert the PTE/PMD into page tables only after that fsync happened. Skip 132155f81639SShiyang Ruan * insertion for now and return the pfn so that caller can insert it after the 132255f81639SShiyang Ruan * fsync is done. 132355f81639SShiyang Ruan */ 132455f81639SShiyang Ruan static vm_fault_t dax_fault_synchronous_pfnp(pfn_t *pfnp, pfn_t pfn) 132555f81639SShiyang Ruan { 132655f81639SShiyang Ruan if (WARN_ON_ONCE(!pfnp)) 132755f81639SShiyang Ruan return VM_FAULT_SIGBUS; 132855f81639SShiyang Ruan *pfnp = pfn; 132955f81639SShiyang Ruan return VM_FAULT_NEEDDSYNC; 133055f81639SShiyang Ruan } 133155f81639SShiyang Ruan 133255f81639SShiyang Ruan static vm_fault_t dax_fault_cow_page(struct vm_fault *vmf, struct iomap *iomap, 133355f81639SShiyang Ruan loff_t pos) 133455f81639SShiyang Ruan { 133555f81639SShiyang Ruan sector_t sector = dax_iomap_sector(iomap, pos); 133655f81639SShiyang Ruan unsigned long vaddr = vmf->address; 133755f81639SShiyang Ruan vm_fault_t ret; 133855f81639SShiyang Ruan int error = 0; 133955f81639SShiyang Ruan 134055f81639SShiyang Ruan switch (iomap->type) { 134155f81639SShiyang Ruan case IOMAP_HOLE: 134255f81639SShiyang Ruan case IOMAP_UNWRITTEN: 134355f81639SShiyang Ruan clear_user_highpage(vmf->cow_page, vaddr); 134455f81639SShiyang Ruan break; 134555f81639SShiyang Ruan case IOMAP_MAPPED: 134655f81639SShiyang Ruan error = copy_cow_page_dax(iomap->bdev, iomap->dax_dev, sector, 134755f81639SShiyang Ruan vmf->cow_page, vaddr); 134855f81639SShiyang Ruan break; 134955f81639SShiyang Ruan default: 135055f81639SShiyang Ruan WARN_ON_ONCE(1); 135155f81639SShiyang Ruan error = -EIO; 135255f81639SShiyang Ruan break; 135355f81639SShiyang Ruan } 135455f81639SShiyang Ruan 135555f81639SShiyang Ruan if (error) 135655f81639SShiyang Ruan return dax_fault_return(error); 135755f81639SShiyang Ruan 135855f81639SShiyang Ruan __SetPageUptodate(vmf->cow_page); 135955f81639SShiyang Ruan ret = finish_fault(vmf); 136055f81639SShiyang Ruan if (!ret) 136155f81639SShiyang Ruan return VM_FAULT_DONE_COW; 136255f81639SShiyang Ruan return ret; 136355f81639SShiyang Ruan } 136455f81639SShiyang Ruan 1365*c2436190SShiyang Ruan /** 1366*c2436190SShiyang Ruan * dax_fault_actor - Common actor to handle pfn insertion in PTE/PMD fault. 1367*c2436190SShiyang Ruan * @vmf: vm fault instance 1368*c2436190SShiyang Ruan * @pfnp: pfn to be returned 1369*c2436190SShiyang Ruan * @xas: the dax mapping tree of a file 1370*c2436190SShiyang Ruan * @entry: an unlocked dax entry to be inserted 1371*c2436190SShiyang Ruan * @pmd: distinguish whether it is a pmd fault 1372*c2436190SShiyang Ruan * @flags: iomap flags 1373*c2436190SShiyang Ruan * @iomap: from iomap_begin() 1374*c2436190SShiyang Ruan * @srcmap: from iomap_begin(), not equal to iomap if it is a CoW 1375*c2436190SShiyang Ruan */ 1376*c2436190SShiyang Ruan static vm_fault_t dax_fault_actor(struct vm_fault *vmf, pfn_t *pfnp, 1377*c2436190SShiyang Ruan struct xa_state *xas, void **entry, bool pmd, 1378*c2436190SShiyang Ruan unsigned int flags, struct iomap *iomap, struct iomap *srcmap) 1379*c2436190SShiyang Ruan { 1380*c2436190SShiyang Ruan struct address_space *mapping = vmf->vma->vm_file->f_mapping; 1381*c2436190SShiyang Ruan size_t size = pmd ? PMD_SIZE : PAGE_SIZE; 1382*c2436190SShiyang Ruan loff_t pos = (loff_t)xas->xa_index << PAGE_SHIFT; 1383*c2436190SShiyang Ruan bool write = vmf->flags & FAULT_FLAG_WRITE; 1384*c2436190SShiyang Ruan bool sync = dax_fault_is_synchronous(flags, vmf->vma, iomap); 1385*c2436190SShiyang Ruan unsigned long entry_flags = pmd ? DAX_PMD : 0; 1386*c2436190SShiyang Ruan int err = 0; 1387*c2436190SShiyang Ruan pfn_t pfn; 1388*c2436190SShiyang Ruan 1389*c2436190SShiyang Ruan /* if we are reading UNWRITTEN and HOLE, return a hole. */ 1390*c2436190SShiyang Ruan if (!write && 1391*c2436190SShiyang Ruan (iomap->type == IOMAP_UNWRITTEN || iomap->type == IOMAP_HOLE)) { 1392*c2436190SShiyang Ruan if (!pmd) 1393*c2436190SShiyang Ruan return dax_load_hole(xas, mapping, entry, vmf); 1394*c2436190SShiyang Ruan return dax_pmd_load_hole(xas, vmf, iomap, entry); 1395*c2436190SShiyang Ruan } 1396*c2436190SShiyang Ruan 1397*c2436190SShiyang Ruan if (iomap->type != IOMAP_MAPPED) { 1398*c2436190SShiyang Ruan WARN_ON_ONCE(1); 1399*c2436190SShiyang Ruan return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS; 1400*c2436190SShiyang Ruan } 1401*c2436190SShiyang Ruan 1402*c2436190SShiyang Ruan err = dax_iomap_pfn(iomap, pos, size, &pfn); 1403*c2436190SShiyang Ruan if (err) 1404*c2436190SShiyang Ruan return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err); 1405*c2436190SShiyang Ruan 1406*c2436190SShiyang Ruan *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, entry_flags, 1407*c2436190SShiyang Ruan write && !sync); 1408*c2436190SShiyang Ruan 1409*c2436190SShiyang Ruan if (sync) 1410*c2436190SShiyang Ruan return dax_fault_synchronous_pfnp(pfnp, pfn); 1411*c2436190SShiyang Ruan 1412*c2436190SShiyang Ruan /* insert PMD pfn */ 1413*c2436190SShiyang Ruan if (pmd) 1414*c2436190SShiyang Ruan return vmf_insert_pfn_pmd(vmf, pfn, write); 1415*c2436190SShiyang Ruan 1416*c2436190SShiyang Ruan /* insert PTE pfn */ 1417*c2436190SShiyang Ruan if (write) 1418*c2436190SShiyang Ruan return vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); 1419*c2436190SShiyang Ruan return vmf_insert_mixed(vmf->vma, vmf->address, pfn); 1420*c2436190SShiyang Ruan } 1421*c2436190SShiyang Ruan 1422ab77dab4SSouptick Joarder static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, 1423c0b24625SJan Kara int *iomap_errp, const struct iomap_ops *ops) 1424a7d73fe6SChristoph Hellwig { 1425a0987ad5SJan Kara struct vm_area_struct *vma = vmf->vma; 1426a0987ad5SJan Kara struct address_space *mapping = vma->vm_file->f_mapping; 1427b15cd800SMatthew Wilcox XA_STATE(xas, &mapping->i_pages, vmf->pgoff); 1428a7d73fe6SChristoph Hellwig struct inode *inode = mapping->host; 1429a7d73fe6SChristoph Hellwig loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; 1430c039b997SGoldwyn Rodrigues struct iomap iomap = { .type = IOMAP_HOLE }; 1431c039b997SGoldwyn Rodrigues struct iomap srcmap = { .type = IOMAP_HOLE }; 14329484ab1bSJan Kara unsigned flags = IOMAP_FAULT; 1433*c2436190SShiyang Ruan int error; 1434d2c43ef1SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 1435*c2436190SShiyang Ruan vm_fault_t ret = 0, major = 0; 1436a7d73fe6SChristoph Hellwig void *entry; 1437a7d73fe6SChristoph Hellwig 1438ab77dab4SSouptick Joarder trace_dax_pte_fault(inode, vmf, ret); 1439a7d73fe6SChristoph Hellwig /* 1440a7d73fe6SChristoph Hellwig * Check whether offset isn't beyond end of file now. Caller is supposed 1441a7d73fe6SChristoph Hellwig * to hold locks serializing us with truncate / punch hole so this is 1442a7d73fe6SChristoph Hellwig * a reliable test. 1443a7d73fe6SChristoph Hellwig */ 1444a9c42b33SRoss Zwisler if (pos >= i_size_read(inode)) { 1445ab77dab4SSouptick Joarder ret = VM_FAULT_SIGBUS; 1446a9c42b33SRoss Zwisler goto out; 1447a9c42b33SRoss Zwisler } 1448a7d73fe6SChristoph Hellwig 1449d2c43ef1SJan Kara if (write && !vmf->cow_page) 1450a7d73fe6SChristoph Hellwig flags |= IOMAP_WRITE; 1451a7d73fe6SChristoph Hellwig 1452b15cd800SMatthew Wilcox entry = grab_mapping_entry(&xas, mapping, 0); 1453b15cd800SMatthew Wilcox if (xa_is_internal(entry)) { 1454b15cd800SMatthew Wilcox ret = xa_to_internal(entry); 145513e451fdSJan Kara goto out; 145613e451fdSJan Kara } 145713e451fdSJan Kara 1458a7d73fe6SChristoph Hellwig /* 1459e2093926SRoss Zwisler * It is possible, particularly with mixed reads & writes to private 1460e2093926SRoss Zwisler * mappings, that we have raced with a PMD fault that overlaps with 1461e2093926SRoss Zwisler * the PTE we need to set up. If so just return and the fault will be 1462e2093926SRoss Zwisler * retried. 1463e2093926SRoss Zwisler */ 1464e2093926SRoss Zwisler if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { 1465ab77dab4SSouptick Joarder ret = VM_FAULT_NOPAGE; 1466e2093926SRoss Zwisler goto unlock_entry; 1467e2093926SRoss Zwisler } 1468e2093926SRoss Zwisler 1469e2093926SRoss Zwisler /* 1470ca289e0bSChristoph Hellwig * Note that we don't bother to use iomap_iter here: DAX required 1471a7d73fe6SChristoph Hellwig * the file system block size to be equal the page size, which means 1472a7d73fe6SChristoph Hellwig * that we never have to deal with more than a single extent here. 1473a7d73fe6SChristoph Hellwig */ 1474c039b997SGoldwyn Rodrigues error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap); 1475c0b24625SJan Kara if (iomap_errp) 1476c0b24625SJan Kara *iomap_errp = error; 1477a9c42b33SRoss Zwisler if (error) { 1478ab77dab4SSouptick Joarder ret = dax_fault_return(error); 147913e451fdSJan Kara goto unlock_entry; 1480a9c42b33SRoss Zwisler } 1481a7d73fe6SChristoph Hellwig if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { 1482*c2436190SShiyang Ruan ret = VM_FAULT_SIGBUS; /* fs corruption? */ 1483*c2436190SShiyang Ruan goto finish_iomap; 1484a7d73fe6SChristoph Hellwig } 1485a7d73fe6SChristoph Hellwig 1486a7d73fe6SChristoph Hellwig if (vmf->cow_page) { 148755f81639SShiyang Ruan ret = dax_fault_cow_page(vmf, &iomap, pos); 148813e451fdSJan Kara goto finish_iomap; 1489a7d73fe6SChristoph Hellwig } 1490a7d73fe6SChristoph Hellwig 1491*c2436190SShiyang Ruan ret = dax_fault_actor(vmf, pfnp, &xas, &entry, false, flags, 1492*c2436190SShiyang Ruan &iomap, &srcmap); 1493*c2436190SShiyang Ruan if (ret == VM_FAULT_SIGBUS) 1494*c2436190SShiyang Ruan goto finish_iomap; 1495caa51d26SJan Kara 1496*c2436190SShiyang Ruan /* read/write MAPPED, CoW UNWRITTEN */ 1497a7d73fe6SChristoph Hellwig if (iomap.flags & IOMAP_F_NEW) { 1498a7d73fe6SChristoph Hellwig count_vm_event(PGMAJFAULT); 1499a0987ad5SJan Kara count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 1500a7d73fe6SChristoph Hellwig major = VM_FAULT_MAJOR; 1501a7d73fe6SChristoph Hellwig } 15021b5a1cb2SJan Kara 15039f141d6eSJan Kara finish_iomap: 15049f141d6eSJan Kara if (ops->iomap_end) { 15059f141d6eSJan Kara int copied = PAGE_SIZE; 15069f141d6eSJan Kara 1507ab77dab4SSouptick Joarder if (ret & VM_FAULT_ERROR) 15089f141d6eSJan Kara copied = 0; 15099f141d6eSJan Kara /* 15109f141d6eSJan Kara * The fault is done by now and there's no way back (other 15119f141d6eSJan Kara * thread may be already happily using PTE we have installed). 15129f141d6eSJan Kara * Just ignore error from ->iomap_end since we cannot do much 15139f141d6eSJan Kara * with it. 15149f141d6eSJan Kara */ 15159f141d6eSJan Kara ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); 15161550290bSRoss Zwisler } 151713e451fdSJan Kara unlock_entry: 1518b15cd800SMatthew Wilcox dax_unlock_entry(&xas, entry); 1519a9c42b33SRoss Zwisler out: 1520ab77dab4SSouptick Joarder trace_dax_pte_fault_done(inode, vmf, ret); 1521ab77dab4SSouptick Joarder return ret | major; 1522a7d73fe6SChristoph Hellwig } 1523642261acSRoss Zwisler 1524642261acSRoss Zwisler #ifdef CONFIG_FS_DAX_PMD 152555f81639SShiyang Ruan static bool dax_fault_check_fallback(struct vm_fault *vmf, struct xa_state *xas, 152655f81639SShiyang Ruan pgoff_t max_pgoff) 152755f81639SShiyang Ruan { 152855f81639SShiyang Ruan unsigned long pmd_addr = vmf->address & PMD_MASK; 152955f81639SShiyang Ruan bool write = vmf->flags & FAULT_FLAG_WRITE; 153055f81639SShiyang Ruan 153155f81639SShiyang Ruan /* 153255f81639SShiyang Ruan * Make sure that the faulting address's PMD offset (color) matches 153355f81639SShiyang Ruan * the PMD offset from the start of the file. This is necessary so 153455f81639SShiyang Ruan * that a PMD range in the page table overlaps exactly with a PMD 153555f81639SShiyang Ruan * range in the page cache. 153655f81639SShiyang Ruan */ 153755f81639SShiyang Ruan if ((vmf->pgoff & PG_PMD_COLOUR) != 153855f81639SShiyang Ruan ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) 153955f81639SShiyang Ruan return true; 154055f81639SShiyang Ruan 154155f81639SShiyang Ruan /* Fall back to PTEs if we're going to COW */ 154255f81639SShiyang Ruan if (write && !(vmf->vma->vm_flags & VM_SHARED)) 154355f81639SShiyang Ruan return true; 154455f81639SShiyang Ruan 154555f81639SShiyang Ruan /* If the PMD would extend outside the VMA */ 154655f81639SShiyang Ruan if (pmd_addr < vmf->vma->vm_start) 154755f81639SShiyang Ruan return true; 154855f81639SShiyang Ruan if ((pmd_addr + PMD_SIZE) > vmf->vma->vm_end) 154955f81639SShiyang Ruan return true; 155055f81639SShiyang Ruan 155155f81639SShiyang Ruan /* If the PMD would extend beyond the file size */ 155255f81639SShiyang Ruan if ((xas->xa_index | PG_PMD_COLOUR) >= max_pgoff) 155355f81639SShiyang Ruan return true; 155455f81639SShiyang Ruan 155555f81639SShiyang Ruan return false; 155655f81639SShiyang Ruan } 155755f81639SShiyang Ruan 1558ab77dab4SSouptick Joarder static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, 1559a2d58167SDave Jiang const struct iomap_ops *ops) 1560642261acSRoss Zwisler { 1561f4200391SDave Jiang struct vm_area_struct *vma = vmf->vma; 1562642261acSRoss Zwisler struct address_space *mapping = vma->vm_file->f_mapping; 1563b15cd800SMatthew Wilcox XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER); 1564d8a849e1SDave Jiang bool write = vmf->flags & FAULT_FLAG_WRITE; 1565*c2436190SShiyang Ruan unsigned int flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; 1566642261acSRoss Zwisler struct inode *inode = mapping->host; 1567*c2436190SShiyang Ruan vm_fault_t ret = VM_FAULT_FALLBACK; 1568c039b997SGoldwyn Rodrigues struct iomap iomap = { .type = IOMAP_HOLE }; 1569c039b997SGoldwyn Rodrigues struct iomap srcmap = { .type = IOMAP_HOLE }; 1570b15cd800SMatthew Wilcox pgoff_t max_pgoff; 1571642261acSRoss Zwisler void *entry; 1572642261acSRoss Zwisler loff_t pos; 1573642261acSRoss Zwisler int error; 1574642261acSRoss Zwisler 1575282a8e03SRoss Zwisler /* 1576282a8e03SRoss Zwisler * Check whether offset isn't beyond end of file now. Caller is 1577282a8e03SRoss Zwisler * supposed to hold locks serializing us with truncate / punch hole so 1578282a8e03SRoss Zwisler * this is a reliable test. 1579282a8e03SRoss Zwisler */ 1580957ac8c4SJeff Moyer max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); 1581282a8e03SRoss Zwisler 1582f4200391SDave Jiang trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); 1583282a8e03SRoss Zwisler 1584b15cd800SMatthew Wilcox if (xas.xa_index >= max_pgoff) { 1585*c2436190SShiyang Ruan ret = VM_FAULT_SIGBUS; 1586282a8e03SRoss Zwisler goto out; 1587282a8e03SRoss Zwisler } 1588642261acSRoss Zwisler 158955f81639SShiyang Ruan if (dax_fault_check_fallback(vmf, &xas, max_pgoff)) 1590642261acSRoss Zwisler goto fallback; 1591642261acSRoss Zwisler 1592642261acSRoss Zwisler /* 1593b15cd800SMatthew Wilcox * grab_mapping_entry() will make sure we get an empty PMD entry, 1594b15cd800SMatthew Wilcox * a zero PMD entry or a DAX PMD. If it can't (because a PTE 1595b15cd800SMatthew Wilcox * entry is already in the array, for instance), it will return 1596b15cd800SMatthew Wilcox * VM_FAULT_FALLBACK. 15979f141d6eSJan Kara */ 159823c84eb7SMatthew Wilcox (Oracle) entry = grab_mapping_entry(&xas, mapping, PMD_ORDER); 1599b15cd800SMatthew Wilcox if (xa_is_internal(entry)) { 1600*c2436190SShiyang Ruan ret = xa_to_internal(entry); 1601876f2946SRoss Zwisler goto fallback; 1602b15cd800SMatthew Wilcox } 1603876f2946SRoss Zwisler 1604876f2946SRoss Zwisler /* 1605e2093926SRoss Zwisler * It is possible, particularly with mixed reads & writes to private 1606e2093926SRoss Zwisler * mappings, that we have raced with a PTE fault that overlaps with 1607e2093926SRoss Zwisler * the PMD we need to set up. If so just return and the fault will be 1608e2093926SRoss Zwisler * retried. 1609e2093926SRoss Zwisler */ 1610e2093926SRoss Zwisler if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && 1611e2093926SRoss Zwisler !pmd_devmap(*vmf->pmd)) { 1612*c2436190SShiyang Ruan ret = 0; 1613e2093926SRoss Zwisler goto unlock_entry; 1614e2093926SRoss Zwisler } 1615e2093926SRoss Zwisler 1616e2093926SRoss Zwisler /* 1617ca289e0bSChristoph Hellwig * Note that we don't use iomap_iter here. We aren't doing I/O, only 1618876f2946SRoss Zwisler * setting up a mapping, so really we're using iomap_begin() as a way 1619876f2946SRoss Zwisler * to look up our filesystem block. 1620876f2946SRoss Zwisler */ 1621b15cd800SMatthew Wilcox pos = (loff_t)xas.xa_index << PAGE_SHIFT; 1622*c2436190SShiyang Ruan error = ops->iomap_begin(inode, pos, PMD_SIZE, flags, &iomap, &srcmap); 1623876f2946SRoss Zwisler if (error) 1624876f2946SRoss Zwisler goto unlock_entry; 1625876f2946SRoss Zwisler 1626876f2946SRoss Zwisler if (iomap.offset + iomap.length < pos + PMD_SIZE) 16279f141d6eSJan Kara goto finish_iomap; 16289f141d6eSJan Kara 1629*c2436190SShiyang Ruan ret = dax_fault_actor(vmf, pfnp, &xas, &entry, true, flags, 1630*c2436190SShiyang Ruan &iomap, &srcmap); 1631642261acSRoss Zwisler 16329f141d6eSJan Kara finish_iomap: 16339f141d6eSJan Kara if (ops->iomap_end) { 16349f141d6eSJan Kara int copied = PMD_SIZE; 16359f141d6eSJan Kara 1636*c2436190SShiyang Ruan if (ret == VM_FAULT_FALLBACK) 16379f141d6eSJan Kara copied = 0; 16389f141d6eSJan Kara /* 16399f141d6eSJan Kara * The fault is done by now and there's no way back (other 16409f141d6eSJan Kara * thread may be already happily using PMD we have installed). 16419f141d6eSJan Kara * Just ignore error from ->iomap_end since we cannot do much 16429f141d6eSJan Kara * with it. 16439f141d6eSJan Kara */ 1644*c2436190SShiyang Ruan ops->iomap_end(inode, pos, PMD_SIZE, copied, flags, &iomap); 16459f141d6eSJan Kara } 1646876f2946SRoss Zwisler unlock_entry: 1647b15cd800SMatthew Wilcox dax_unlock_entry(&xas, entry); 1648642261acSRoss Zwisler fallback: 1649*c2436190SShiyang Ruan if (ret == VM_FAULT_FALLBACK) { 1650d8a849e1SDave Jiang split_huge_pmd(vma, vmf->pmd, vmf->address); 1651642261acSRoss Zwisler count_vm_event(THP_FAULT_FALLBACK); 1652642261acSRoss Zwisler } 1653282a8e03SRoss Zwisler out: 1654*c2436190SShiyang Ruan trace_dax_pmd_fault_done(inode, vmf, max_pgoff, ret); 1655*c2436190SShiyang Ruan return ret; 1656642261acSRoss Zwisler } 1657a2d58167SDave Jiang #else 1658ab77dab4SSouptick Joarder static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, 165901cddfe9SArnd Bergmann const struct iomap_ops *ops) 1660a2d58167SDave Jiang { 1661a2d58167SDave Jiang return VM_FAULT_FALLBACK; 1662a2d58167SDave Jiang } 1663642261acSRoss Zwisler #endif /* CONFIG_FS_DAX_PMD */ 1664a2d58167SDave Jiang 1665a2d58167SDave Jiang /** 1666a2d58167SDave Jiang * dax_iomap_fault - handle a page fault on a DAX file 1667a2d58167SDave Jiang * @vmf: The description of the fault 1668cec04e8cSJan Kara * @pe_size: Size of the page to fault in 16699a0dd422SJan Kara * @pfnp: PFN to insert for synchronous faults if fsync is required 1670c0b24625SJan Kara * @iomap_errp: Storage for detailed error code in case of error 1671cec04e8cSJan Kara * @ops: Iomap ops passed from the file system 1672a2d58167SDave Jiang * 1673a2d58167SDave Jiang * When a page fault occurs, filesystems may call this helper in 1674a2d58167SDave Jiang * their fault handler for DAX files. dax_iomap_fault() assumes the caller 1675a2d58167SDave Jiang * has done all the necessary locking for page fault to proceed 1676a2d58167SDave Jiang * successfully. 1677a2d58167SDave Jiang */ 1678ab77dab4SSouptick Joarder vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 1679c0b24625SJan Kara pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) 1680a2d58167SDave Jiang { 1681c791ace1SDave Jiang switch (pe_size) { 1682c791ace1SDave Jiang case PE_SIZE_PTE: 1683c0b24625SJan Kara return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops); 1684c791ace1SDave Jiang case PE_SIZE_PMD: 16859a0dd422SJan Kara return dax_iomap_pmd_fault(vmf, pfnp, ops); 1686a2d58167SDave Jiang default: 1687a2d58167SDave Jiang return VM_FAULT_FALLBACK; 1688a2d58167SDave Jiang } 1689a2d58167SDave Jiang } 1690a2d58167SDave Jiang EXPORT_SYMBOL_GPL(dax_iomap_fault); 169171eab6dfSJan Kara 1692a77d19f4SMatthew Wilcox /* 169371eab6dfSJan Kara * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables 169471eab6dfSJan Kara * @vmf: The description of the fault 169571eab6dfSJan Kara * @pfn: PFN to insert 1696cfc93c6cSMatthew Wilcox * @order: Order of entry to insert. 169771eab6dfSJan Kara * 1698a77d19f4SMatthew Wilcox * This function inserts a writeable PTE or PMD entry into the page tables 1699a77d19f4SMatthew Wilcox * for an mmaped DAX file. It also marks the page cache entry as dirty. 170071eab6dfSJan Kara */ 1701cfc93c6cSMatthew Wilcox static vm_fault_t 1702cfc93c6cSMatthew Wilcox dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order) 170371eab6dfSJan Kara { 170471eab6dfSJan Kara struct address_space *mapping = vmf->vma->vm_file->f_mapping; 1705cfc93c6cSMatthew Wilcox XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, order); 1706cfc93c6cSMatthew Wilcox void *entry; 1707ab77dab4SSouptick Joarder vm_fault_t ret; 170871eab6dfSJan Kara 1709cfc93c6cSMatthew Wilcox xas_lock_irq(&xas); 171023c84eb7SMatthew Wilcox (Oracle) entry = get_unlocked_entry(&xas, order); 171171eab6dfSJan Kara /* Did we race with someone splitting entry or so? */ 171223c84eb7SMatthew Wilcox (Oracle) if (!entry || dax_is_conflict(entry) || 171323c84eb7SMatthew Wilcox (Oracle) (order == 0 && !dax_is_pte_entry(entry))) { 17144c3d043dSVivek Goyal put_unlocked_entry(&xas, entry, WAKE_NEXT); 1715cfc93c6cSMatthew Wilcox xas_unlock_irq(&xas); 171671eab6dfSJan Kara trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, 171771eab6dfSJan Kara VM_FAULT_NOPAGE); 171871eab6dfSJan Kara return VM_FAULT_NOPAGE; 171971eab6dfSJan Kara } 1720cfc93c6cSMatthew Wilcox xas_set_mark(&xas, PAGECACHE_TAG_DIRTY); 1721cfc93c6cSMatthew Wilcox dax_lock_entry(&xas, entry); 1722cfc93c6cSMatthew Wilcox xas_unlock_irq(&xas); 1723cfc93c6cSMatthew Wilcox if (order == 0) 1724ab77dab4SSouptick Joarder ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); 172571eab6dfSJan Kara #ifdef CONFIG_FS_DAX_PMD 1726cfc93c6cSMatthew Wilcox else if (order == PMD_ORDER) 1727fce86ff5SDan Williams ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE); 172871eab6dfSJan Kara #endif 1729cfc93c6cSMatthew Wilcox else 1730ab77dab4SSouptick Joarder ret = VM_FAULT_FALLBACK; 1731cfc93c6cSMatthew Wilcox dax_unlock_entry(&xas, entry); 1732ab77dab4SSouptick Joarder trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret); 1733ab77dab4SSouptick Joarder return ret; 173471eab6dfSJan Kara } 173571eab6dfSJan Kara 173671eab6dfSJan Kara /** 173771eab6dfSJan Kara * dax_finish_sync_fault - finish synchronous page fault 173871eab6dfSJan Kara * @vmf: The description of the fault 173971eab6dfSJan Kara * @pe_size: Size of entry to be inserted 174071eab6dfSJan Kara * @pfn: PFN to insert 174171eab6dfSJan Kara * 174271eab6dfSJan Kara * This function ensures that the file range touched by the page fault is 174371eab6dfSJan Kara * stored persistently on the media and handles inserting of appropriate page 174471eab6dfSJan Kara * table entry. 174571eab6dfSJan Kara */ 1746ab77dab4SSouptick Joarder vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, 1747ab77dab4SSouptick Joarder enum page_entry_size pe_size, pfn_t pfn) 174871eab6dfSJan Kara { 174971eab6dfSJan Kara int err; 175071eab6dfSJan Kara loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; 1751cfc93c6cSMatthew Wilcox unsigned int order = pe_order(pe_size); 1752cfc93c6cSMatthew Wilcox size_t len = PAGE_SIZE << order; 175371eab6dfSJan Kara 175471eab6dfSJan Kara err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); 175571eab6dfSJan Kara if (err) 175671eab6dfSJan Kara return VM_FAULT_SIGBUS; 1757cfc93c6cSMatthew Wilcox return dax_insert_pfn_mkwrite(vmf, pfn, order); 175871eab6dfSJan Kara } 175971eab6dfSJan Kara EXPORT_SYMBOL_GPL(dax_finish_sync_fault); 1760