1d475c634SMatthew Wilcox /* 2d475c634SMatthew Wilcox * fs/dax.c - Direct Access filesystem code 3d475c634SMatthew Wilcox * Copyright (c) 2013-2014 Intel Corporation 4d475c634SMatthew Wilcox * Author: Matthew Wilcox <matthew.r.wilcox@intel.com> 5d475c634SMatthew Wilcox * Author: Ross Zwisler <ross.zwisler@linux.intel.com> 6d475c634SMatthew Wilcox * 7d475c634SMatthew Wilcox * This program is free software; you can redistribute it and/or modify it 8d475c634SMatthew Wilcox * under the terms and conditions of the GNU General Public License, 9d475c634SMatthew Wilcox * version 2, as published by the Free Software Foundation. 10d475c634SMatthew Wilcox * 11d475c634SMatthew Wilcox * This program is distributed in the hope it will be useful, but WITHOUT 12d475c634SMatthew Wilcox * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13d475c634SMatthew Wilcox * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14d475c634SMatthew Wilcox * more details. 15d475c634SMatthew Wilcox */ 16d475c634SMatthew Wilcox 17d475c634SMatthew Wilcox #include <linux/atomic.h> 18d475c634SMatthew Wilcox #include <linux/blkdev.h> 19d475c634SMatthew Wilcox #include <linux/buffer_head.h> 20d77e92e2SRoss Zwisler #include <linux/dax.h> 21d475c634SMatthew Wilcox #include <linux/fs.h> 22d475c634SMatthew Wilcox #include <linux/genhd.h> 23f7ca90b1SMatthew Wilcox #include <linux/highmem.h> 24f7ca90b1SMatthew Wilcox #include <linux/memcontrol.h> 25f7ca90b1SMatthew Wilcox #include <linux/mm.h> 26d475c634SMatthew Wilcox #include <linux/mutex.h> 279973c98eSRoss Zwisler #include <linux/pagevec.h> 28289c6aedSMatthew Wilcox #include <linux/sched.h> 29f361bf4aSIngo Molnar #include <linux/sched/signal.h> 30d475c634SMatthew Wilcox #include <linux/uio.h> 31f7ca90b1SMatthew Wilcox #include <linux/vmstat.h> 3234c0fd54SDan Williams #include <linux/pfn_t.h> 330e749e54SDan Williams #include <linux/sizes.h> 344b4bb46dSJan Kara #include <linux/mmu_notifier.h> 35a254e568SChristoph Hellwig #include <linux/iomap.h> 36a254e568SChristoph Hellwig #include "internal.h" 37d475c634SMatthew Wilcox 38282a8e03SRoss Zwisler #define CREATE_TRACE_POINTS 39282a8e03SRoss Zwisler #include <trace/events/fs_dax.h> 40282a8e03SRoss Zwisler 41ac401cc7SJan Kara /* We choose 4096 entries - same as per-zone page wait tables */ 42ac401cc7SJan Kara #define DAX_WAIT_TABLE_BITS 12 43ac401cc7SJan Kara #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) 44ac401cc7SJan Kara 45917f3452SRoss Zwisler /* The 'colour' (ie low bits) within a PMD of a page offset. */ 46917f3452SRoss Zwisler #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) 47977fbdcdSMatthew Wilcox #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) 48917f3452SRoss Zwisler 49ce95ab0fSRoss Zwisler static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; 50ac401cc7SJan Kara 51ac401cc7SJan Kara static int __init init_dax_wait_table(void) 52ac401cc7SJan Kara { 53ac401cc7SJan Kara int i; 54ac401cc7SJan Kara 55ac401cc7SJan Kara for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) 56ac401cc7SJan Kara init_waitqueue_head(wait_table + i); 57ac401cc7SJan Kara return 0; 58ac401cc7SJan Kara } 59ac401cc7SJan Kara fs_initcall(init_dax_wait_table); 60ac401cc7SJan Kara 61527b19d0SRoss Zwisler /* 62527b19d0SRoss Zwisler * We use lowest available bit in exceptional entry for locking, one bit for 63527b19d0SRoss Zwisler * the entry size (PMD) and two more to tell us if the entry is a zero page or 64527b19d0SRoss Zwisler * an empty entry that is just used for locking. In total four special bits. 65527b19d0SRoss Zwisler * 66527b19d0SRoss Zwisler * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE 67527b19d0SRoss Zwisler * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem 68527b19d0SRoss Zwisler * block allocation. 69527b19d0SRoss Zwisler */ 70527b19d0SRoss Zwisler #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4) 71527b19d0SRoss Zwisler #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT) 72527b19d0SRoss Zwisler #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) 73527b19d0SRoss Zwisler #define RADIX_DAX_ZERO_PAGE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) 74527b19d0SRoss Zwisler #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) 75527b19d0SRoss Zwisler 763fe0791cSDan Williams static unsigned long dax_radix_pfn(void *entry) 77527b19d0SRoss Zwisler { 78527b19d0SRoss Zwisler return (unsigned long)entry >> RADIX_DAX_SHIFT; 79527b19d0SRoss Zwisler } 80527b19d0SRoss Zwisler 813fe0791cSDan Williams static void *dax_radix_locked_entry(unsigned long pfn, unsigned long flags) 82527b19d0SRoss Zwisler { 83527b19d0SRoss Zwisler return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | 843fe0791cSDan Williams (pfn << RADIX_DAX_SHIFT) | RADIX_DAX_ENTRY_LOCK); 85527b19d0SRoss Zwisler } 86527b19d0SRoss Zwisler 87527b19d0SRoss Zwisler static unsigned int dax_radix_order(void *entry) 88527b19d0SRoss Zwisler { 89527b19d0SRoss Zwisler if ((unsigned long)entry & RADIX_DAX_PMD) 90527b19d0SRoss Zwisler return PMD_SHIFT - PAGE_SHIFT; 91527b19d0SRoss Zwisler return 0; 92527b19d0SRoss Zwisler } 93527b19d0SRoss Zwisler 94642261acSRoss Zwisler static int dax_is_pmd_entry(void *entry) 95642261acSRoss Zwisler { 96642261acSRoss Zwisler return (unsigned long)entry & RADIX_DAX_PMD; 97642261acSRoss Zwisler } 98642261acSRoss Zwisler 99642261acSRoss Zwisler static int dax_is_pte_entry(void *entry) 100642261acSRoss Zwisler { 101642261acSRoss Zwisler return !((unsigned long)entry & RADIX_DAX_PMD); 102642261acSRoss Zwisler } 103642261acSRoss Zwisler 104642261acSRoss Zwisler static int dax_is_zero_entry(void *entry) 105642261acSRoss Zwisler { 10691d25ba8SRoss Zwisler return (unsigned long)entry & RADIX_DAX_ZERO_PAGE; 107642261acSRoss Zwisler } 108642261acSRoss Zwisler 109642261acSRoss Zwisler static int dax_is_empty_entry(void *entry) 110642261acSRoss Zwisler { 111642261acSRoss Zwisler return (unsigned long)entry & RADIX_DAX_EMPTY; 112642261acSRoss Zwisler } 113642261acSRoss Zwisler 114f7ca90b1SMatthew Wilcox /* 115ac401cc7SJan Kara * DAX radix tree locking 116ac401cc7SJan Kara */ 117ac401cc7SJan Kara struct exceptional_entry_key { 118ac401cc7SJan Kara struct address_space *mapping; 11963e95b5cSRoss Zwisler pgoff_t entry_start; 120ac401cc7SJan Kara }; 121ac401cc7SJan Kara 122ac401cc7SJan Kara struct wait_exceptional_entry_queue { 123ac6424b9SIngo Molnar wait_queue_entry_t wait; 124ac401cc7SJan Kara struct exceptional_entry_key key; 125ac401cc7SJan Kara }; 126ac401cc7SJan Kara 12763e95b5cSRoss Zwisler static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, 12863e95b5cSRoss Zwisler pgoff_t index, void *entry, struct exceptional_entry_key *key) 12963e95b5cSRoss Zwisler { 13063e95b5cSRoss Zwisler unsigned long hash; 13163e95b5cSRoss Zwisler 13263e95b5cSRoss Zwisler /* 13363e95b5cSRoss Zwisler * If 'entry' is a PMD, align the 'index' that we use for the wait 13463e95b5cSRoss Zwisler * queue to the start of that PMD. This ensures that all offsets in 13563e95b5cSRoss Zwisler * the range covered by the PMD map to the same bit lock. 13663e95b5cSRoss Zwisler */ 137642261acSRoss Zwisler if (dax_is_pmd_entry(entry)) 138917f3452SRoss Zwisler index &= ~PG_PMD_COLOUR; 13963e95b5cSRoss Zwisler 14063e95b5cSRoss Zwisler key->mapping = mapping; 14163e95b5cSRoss Zwisler key->entry_start = index; 14263e95b5cSRoss Zwisler 14363e95b5cSRoss Zwisler hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); 14463e95b5cSRoss Zwisler return wait_table + hash; 14563e95b5cSRoss Zwisler } 14663e95b5cSRoss Zwisler 147ac6424b9SIngo Molnar static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mode, 148ac401cc7SJan Kara int sync, void *keyp) 149ac401cc7SJan Kara { 150ac401cc7SJan Kara struct exceptional_entry_key *key = keyp; 151ac401cc7SJan Kara struct wait_exceptional_entry_queue *ewait = 152ac401cc7SJan Kara container_of(wait, struct wait_exceptional_entry_queue, wait); 153ac401cc7SJan Kara 154ac401cc7SJan Kara if (key->mapping != ewait->key.mapping || 15563e95b5cSRoss Zwisler key->entry_start != ewait->key.entry_start) 156ac401cc7SJan Kara return 0; 157ac401cc7SJan Kara return autoremove_wake_function(wait, mode, sync, NULL); 158ac401cc7SJan Kara } 159ac401cc7SJan Kara 160ac401cc7SJan Kara /* 161b93b0163SMatthew Wilcox * @entry may no longer be the entry at the index in the mapping. 162b93b0163SMatthew Wilcox * The important information it's conveying is whether the entry at 163b93b0163SMatthew Wilcox * this index used to be a PMD entry. 164e30331ffSRoss Zwisler */ 165d01ad197SRoss Zwisler static void dax_wake_mapping_entry_waiter(struct address_space *mapping, 166e30331ffSRoss Zwisler pgoff_t index, void *entry, bool wake_all) 167e30331ffSRoss Zwisler { 168e30331ffSRoss Zwisler struct exceptional_entry_key key; 169e30331ffSRoss Zwisler wait_queue_head_t *wq; 170e30331ffSRoss Zwisler 171e30331ffSRoss Zwisler wq = dax_entry_waitqueue(mapping, index, entry, &key); 172e30331ffSRoss Zwisler 173e30331ffSRoss Zwisler /* 174e30331ffSRoss Zwisler * Checking for locked entry and prepare_to_wait_exclusive() happens 175b93b0163SMatthew Wilcox * under the i_pages lock, ditto for entry handling in our callers. 176e30331ffSRoss Zwisler * So at this point all tasks that could have seen our entry locked 177e30331ffSRoss Zwisler * must be in the waitqueue and the following check will see them. 178e30331ffSRoss Zwisler */ 179e30331ffSRoss Zwisler if (waitqueue_active(wq)) 180e30331ffSRoss Zwisler __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); 181e30331ffSRoss Zwisler } 182e30331ffSRoss Zwisler 183e30331ffSRoss Zwisler /* 184b93b0163SMatthew Wilcox * Check whether the given slot is locked. Must be called with the i_pages 185b93b0163SMatthew Wilcox * lock held. 186ac401cc7SJan Kara */ 187ac401cc7SJan Kara static inline int slot_locked(struct address_space *mapping, void **slot) 188ac401cc7SJan Kara { 189ac401cc7SJan Kara unsigned long entry = (unsigned long) 190b93b0163SMatthew Wilcox radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); 191ac401cc7SJan Kara return entry & RADIX_DAX_ENTRY_LOCK; 192ac401cc7SJan Kara } 193ac401cc7SJan Kara 194ac401cc7SJan Kara /* 195b93b0163SMatthew Wilcox * Mark the given slot as locked. Must be called with the i_pages lock held. 196ac401cc7SJan Kara */ 197ac401cc7SJan Kara static inline void *lock_slot(struct address_space *mapping, void **slot) 198ac401cc7SJan Kara { 199ac401cc7SJan Kara unsigned long entry = (unsigned long) 200b93b0163SMatthew Wilcox radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); 201ac401cc7SJan Kara 202ac401cc7SJan Kara entry |= RADIX_DAX_ENTRY_LOCK; 203b93b0163SMatthew Wilcox radix_tree_replace_slot(&mapping->i_pages, slot, (void *)entry); 204ac401cc7SJan Kara return (void *)entry; 205ac401cc7SJan Kara } 206ac401cc7SJan Kara 207ac401cc7SJan Kara /* 208b93b0163SMatthew Wilcox * Mark the given slot as unlocked. Must be called with the i_pages lock held. 209ac401cc7SJan Kara */ 210ac401cc7SJan Kara static inline void *unlock_slot(struct address_space *mapping, void **slot) 211ac401cc7SJan Kara { 212ac401cc7SJan Kara unsigned long entry = (unsigned long) 213b93b0163SMatthew Wilcox radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock); 214ac401cc7SJan Kara 215ac401cc7SJan Kara entry &= ~(unsigned long)RADIX_DAX_ENTRY_LOCK; 216b93b0163SMatthew Wilcox radix_tree_replace_slot(&mapping->i_pages, slot, (void *)entry); 217ac401cc7SJan Kara return (void *)entry; 218ac401cc7SJan Kara } 219ac401cc7SJan Kara 220ac401cc7SJan Kara /* 221ac401cc7SJan Kara * Lookup entry in radix tree, wait for it to become unlocked if it is 222ac401cc7SJan Kara * exceptional entry and return it. The caller must call 223ac401cc7SJan Kara * put_unlocked_mapping_entry() when he decided not to lock the entry or 224ac401cc7SJan Kara * put_locked_mapping_entry() when he locked the entry and now wants to 225ac401cc7SJan Kara * unlock it. 226ac401cc7SJan Kara * 227b93b0163SMatthew Wilcox * Must be called with the i_pages lock held. 228ac401cc7SJan Kara */ 229ac401cc7SJan Kara static void *get_unlocked_mapping_entry(struct address_space *mapping, 230ac401cc7SJan Kara pgoff_t index, void ***slotp) 231ac401cc7SJan Kara { 232e3ad61c6SRoss Zwisler void *entry, **slot; 233ac401cc7SJan Kara struct wait_exceptional_entry_queue ewait; 23463e95b5cSRoss Zwisler wait_queue_head_t *wq; 235ac401cc7SJan Kara 236ac401cc7SJan Kara init_wait(&ewait.wait); 237ac401cc7SJan Kara ewait.wait.func = wake_exceptional_entry_func; 238ac401cc7SJan Kara 239ac401cc7SJan Kara for (;;) { 240b93b0163SMatthew Wilcox entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, 241ac401cc7SJan Kara &slot); 24291d25ba8SRoss Zwisler if (!entry || 24391d25ba8SRoss Zwisler WARN_ON_ONCE(!radix_tree_exceptional_entry(entry)) || 244ac401cc7SJan Kara !slot_locked(mapping, slot)) { 245ac401cc7SJan Kara if (slotp) 246ac401cc7SJan Kara *slotp = slot; 247e3ad61c6SRoss Zwisler return entry; 248ac401cc7SJan Kara } 24963e95b5cSRoss Zwisler 25063e95b5cSRoss Zwisler wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); 251ac401cc7SJan Kara prepare_to_wait_exclusive(wq, &ewait.wait, 252ac401cc7SJan Kara TASK_UNINTERRUPTIBLE); 253b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 254ac401cc7SJan Kara schedule(); 255ac401cc7SJan Kara finish_wait(wq, &ewait.wait); 256b93b0163SMatthew Wilcox xa_lock_irq(&mapping->i_pages); 257ac401cc7SJan Kara } 258ac401cc7SJan Kara } 259ac401cc7SJan Kara 260b1aa812bSJan Kara static void dax_unlock_mapping_entry(struct address_space *mapping, 261b1aa812bSJan Kara pgoff_t index) 262b1aa812bSJan Kara { 263b1aa812bSJan Kara void *entry, **slot; 264b1aa812bSJan Kara 265b93b0163SMatthew Wilcox xa_lock_irq(&mapping->i_pages); 266b93b0163SMatthew Wilcox entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, &slot); 267b1aa812bSJan Kara if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) || 268b1aa812bSJan Kara !slot_locked(mapping, slot))) { 269b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 270b1aa812bSJan Kara return; 271b1aa812bSJan Kara } 272b1aa812bSJan Kara unlock_slot(mapping, slot); 273b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 274b1aa812bSJan Kara dax_wake_mapping_entry_waiter(mapping, index, entry, false); 275b1aa812bSJan Kara } 276b1aa812bSJan Kara 277ac401cc7SJan Kara static void put_locked_mapping_entry(struct address_space *mapping, 27891d25ba8SRoss Zwisler pgoff_t index) 279ac401cc7SJan Kara { 280bc2466e4SJan Kara dax_unlock_mapping_entry(mapping, index); 281ac401cc7SJan Kara } 282ac401cc7SJan Kara 283ac401cc7SJan Kara /* 284ac401cc7SJan Kara * Called when we are done with radix tree entry we looked up via 285ac401cc7SJan Kara * get_unlocked_mapping_entry() and which we didn't lock in the end. 286ac401cc7SJan Kara */ 287ac401cc7SJan Kara static void put_unlocked_mapping_entry(struct address_space *mapping, 288ac401cc7SJan Kara pgoff_t index, void *entry) 289ac401cc7SJan Kara { 29091d25ba8SRoss Zwisler if (!entry) 291ac401cc7SJan Kara return; 292ac401cc7SJan Kara 293ac401cc7SJan Kara /* We have to wake up next waiter for the radix tree entry lock */ 294422476c4SRoss Zwisler dax_wake_mapping_entry_waiter(mapping, index, entry, false); 295422476c4SRoss Zwisler } 296422476c4SRoss Zwisler 297d2c997c0SDan Williams static unsigned long dax_entry_size(void *entry) 298d2c997c0SDan Williams { 299d2c997c0SDan Williams if (dax_is_zero_entry(entry)) 300d2c997c0SDan Williams return 0; 301d2c997c0SDan Williams else if (dax_is_empty_entry(entry)) 302d2c997c0SDan Williams return 0; 303d2c997c0SDan Williams else if (dax_is_pmd_entry(entry)) 304d2c997c0SDan Williams return PMD_SIZE; 305d2c997c0SDan Williams else 306d2c997c0SDan Williams return PAGE_SIZE; 307d2c997c0SDan Williams } 308d2c997c0SDan Williams 309d2c997c0SDan Williams static unsigned long dax_radix_end_pfn(void *entry) 310d2c997c0SDan Williams { 311d2c997c0SDan Williams return dax_radix_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE; 312d2c997c0SDan Williams } 313d2c997c0SDan Williams 314d2c997c0SDan Williams /* 315d2c997c0SDan Williams * Iterate through all mapped pfns represented by an entry, i.e. skip 316d2c997c0SDan Williams * 'empty' and 'zero' entries. 317d2c997c0SDan Williams */ 318d2c997c0SDan Williams #define for_each_mapped_pfn(entry, pfn) \ 319d2c997c0SDan Williams for (pfn = dax_radix_pfn(entry); \ 320d2c997c0SDan Williams pfn < dax_radix_end_pfn(entry); pfn++) 321d2c997c0SDan Williams 322d2c997c0SDan Williams static void dax_associate_entry(void *entry, struct address_space *mapping) 323d2c997c0SDan Williams { 324d2c997c0SDan Williams unsigned long pfn; 325d2c997c0SDan Williams 326d2c997c0SDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 327d2c997c0SDan Williams return; 328d2c997c0SDan Williams 329d2c997c0SDan Williams for_each_mapped_pfn(entry, pfn) { 330d2c997c0SDan Williams struct page *page = pfn_to_page(pfn); 331d2c997c0SDan Williams 332d2c997c0SDan Williams WARN_ON_ONCE(page->mapping); 333d2c997c0SDan Williams page->mapping = mapping; 334d2c997c0SDan Williams } 335d2c997c0SDan Williams } 336d2c997c0SDan Williams 337d2c997c0SDan Williams static void dax_disassociate_entry(void *entry, struct address_space *mapping, 338d2c997c0SDan Williams bool trunc) 339d2c997c0SDan Williams { 340d2c997c0SDan Williams unsigned long pfn; 341d2c997c0SDan Williams 342d2c997c0SDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) 343d2c997c0SDan Williams return; 344d2c997c0SDan Williams 345d2c997c0SDan Williams for_each_mapped_pfn(entry, pfn) { 346d2c997c0SDan Williams struct page *page = pfn_to_page(pfn); 347d2c997c0SDan Williams 348d2c997c0SDan Williams WARN_ON_ONCE(trunc && page_ref_count(page) > 1); 349d2c997c0SDan Williams WARN_ON_ONCE(page->mapping && page->mapping != mapping); 350d2c997c0SDan Williams page->mapping = NULL; 351d2c997c0SDan Williams } 352d2c997c0SDan Williams } 353d2c997c0SDan Williams 354ac401cc7SJan Kara /* 35591d25ba8SRoss Zwisler * Find radix tree entry at given index. If it points to an exceptional entry, 35691d25ba8SRoss Zwisler * return it with the radix tree entry locked. If the radix tree doesn't 35791d25ba8SRoss Zwisler * contain given index, create an empty exceptional entry for the index and 35891d25ba8SRoss Zwisler * return with it locked. 359ac401cc7SJan Kara * 360642261acSRoss Zwisler * When requesting an entry with size RADIX_DAX_PMD, grab_mapping_entry() will 361642261acSRoss Zwisler * either return that locked entry or will return an error. This error will 36291d25ba8SRoss Zwisler * happen if there are any 4k entries within the 2MiB range that we are 36391d25ba8SRoss Zwisler * requesting. 364642261acSRoss Zwisler * 365642261acSRoss Zwisler * We always favor 4k entries over 2MiB entries. There isn't a flow where we 366642261acSRoss Zwisler * evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB 367642261acSRoss Zwisler * insertion will fail if it finds any 4k entries already in the tree, and a 368642261acSRoss Zwisler * 4k insertion will cause an existing 2MiB entry to be unmapped and 369642261acSRoss Zwisler * downgraded to 4k entries. This happens for both 2MiB huge zero pages as 370642261acSRoss Zwisler * well as 2MiB empty entries. 371642261acSRoss Zwisler * 372642261acSRoss Zwisler * The exception to this downgrade path is for 2MiB DAX PMD entries that have 373642261acSRoss Zwisler * real storage backing them. We will leave these real 2MiB DAX entries in 374642261acSRoss Zwisler * the tree, and PTE writes will simply dirty the entire 2MiB DAX entry. 375642261acSRoss Zwisler * 376ac401cc7SJan Kara * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For 377ac401cc7SJan Kara * persistent memory the benefit is doubtful. We can add that later if we can 378ac401cc7SJan Kara * show it helps. 379ac401cc7SJan Kara */ 380642261acSRoss Zwisler static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, 381642261acSRoss Zwisler unsigned long size_flag) 382ac401cc7SJan Kara { 383642261acSRoss Zwisler bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */ 384e3ad61c6SRoss Zwisler void *entry, **slot; 385ac401cc7SJan Kara 386ac401cc7SJan Kara restart: 387b93b0163SMatthew Wilcox xa_lock_irq(&mapping->i_pages); 388e3ad61c6SRoss Zwisler entry = get_unlocked_mapping_entry(mapping, index, &slot); 389642261acSRoss Zwisler 39091d25ba8SRoss Zwisler if (WARN_ON_ONCE(entry && !radix_tree_exceptional_entry(entry))) { 39191d25ba8SRoss Zwisler entry = ERR_PTR(-EIO); 39291d25ba8SRoss Zwisler goto out_unlock; 39391d25ba8SRoss Zwisler } 39491d25ba8SRoss Zwisler 395642261acSRoss Zwisler if (entry) { 396642261acSRoss Zwisler if (size_flag & RADIX_DAX_PMD) { 39791d25ba8SRoss Zwisler if (dax_is_pte_entry(entry)) { 398642261acSRoss Zwisler put_unlocked_mapping_entry(mapping, index, 399642261acSRoss Zwisler entry); 400642261acSRoss Zwisler entry = ERR_PTR(-EEXIST); 401642261acSRoss Zwisler goto out_unlock; 402642261acSRoss Zwisler } 403642261acSRoss Zwisler } else { /* trying to grab a PTE entry */ 40491d25ba8SRoss Zwisler if (dax_is_pmd_entry(entry) && 405642261acSRoss Zwisler (dax_is_zero_entry(entry) || 406642261acSRoss Zwisler dax_is_empty_entry(entry))) { 407642261acSRoss Zwisler pmd_downgrade = true; 408642261acSRoss Zwisler } 409642261acSRoss Zwisler } 410642261acSRoss Zwisler } 411642261acSRoss Zwisler 412ac401cc7SJan Kara /* No entry for given index? Make sure radix tree is big enough. */ 413642261acSRoss Zwisler if (!entry || pmd_downgrade) { 414ac401cc7SJan Kara int err; 415ac401cc7SJan Kara 416642261acSRoss Zwisler if (pmd_downgrade) { 417642261acSRoss Zwisler /* 418642261acSRoss Zwisler * Make sure 'entry' remains valid while we drop 419b93b0163SMatthew Wilcox * the i_pages lock. 420642261acSRoss Zwisler */ 421642261acSRoss Zwisler entry = lock_slot(mapping, slot); 422642261acSRoss Zwisler } 423642261acSRoss Zwisler 424b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 425642261acSRoss Zwisler /* 426642261acSRoss Zwisler * Besides huge zero pages the only other thing that gets 427642261acSRoss Zwisler * downgraded are empty entries which don't need to be 428642261acSRoss Zwisler * unmapped. 429642261acSRoss Zwisler */ 430642261acSRoss Zwisler if (pmd_downgrade && dax_is_zero_entry(entry)) 431977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, 432977fbdcdSMatthew Wilcox PG_PMD_NR, false); 433642261acSRoss Zwisler 4340cb80b48SJan Kara err = radix_tree_preload( 4350cb80b48SJan Kara mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); 4360cb80b48SJan Kara if (err) { 4370cb80b48SJan Kara if (pmd_downgrade) 43891d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, index); 4390cb80b48SJan Kara return ERR_PTR(err); 4400cb80b48SJan Kara } 441b93b0163SMatthew Wilcox xa_lock_irq(&mapping->i_pages); 442642261acSRoss Zwisler 443e11f8b7bSRoss Zwisler if (!entry) { 444e11f8b7bSRoss Zwisler /* 445b93b0163SMatthew Wilcox * We needed to drop the i_pages lock while calling 446e11f8b7bSRoss Zwisler * radix_tree_preload() and we didn't have an entry to 447e11f8b7bSRoss Zwisler * lock. See if another thread inserted an entry at 448e11f8b7bSRoss Zwisler * our index during this time. 449e11f8b7bSRoss Zwisler */ 450b93b0163SMatthew Wilcox entry = __radix_tree_lookup(&mapping->i_pages, index, 451e11f8b7bSRoss Zwisler NULL, &slot); 452e11f8b7bSRoss Zwisler if (entry) { 453e11f8b7bSRoss Zwisler radix_tree_preload_end(); 454b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 455e11f8b7bSRoss Zwisler goto restart; 456e11f8b7bSRoss Zwisler } 457e11f8b7bSRoss Zwisler } 458e11f8b7bSRoss Zwisler 459642261acSRoss Zwisler if (pmd_downgrade) { 460d2c997c0SDan Williams dax_disassociate_entry(entry, mapping, false); 461b93b0163SMatthew Wilcox radix_tree_delete(&mapping->i_pages, index); 462642261acSRoss Zwisler mapping->nrexceptional--; 463642261acSRoss Zwisler dax_wake_mapping_entry_waiter(mapping, index, entry, 464642261acSRoss Zwisler true); 465642261acSRoss Zwisler } 466642261acSRoss Zwisler 467642261acSRoss Zwisler entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY); 468642261acSRoss Zwisler 469b93b0163SMatthew Wilcox err = __radix_tree_insert(&mapping->i_pages, index, 470642261acSRoss Zwisler dax_radix_order(entry), entry); 471ac401cc7SJan Kara radix_tree_preload_end(); 472ac401cc7SJan Kara if (err) { 473b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 474642261acSRoss Zwisler /* 475e11f8b7bSRoss Zwisler * Our insertion of a DAX entry failed, most likely 476e11f8b7bSRoss Zwisler * because we were inserting a PMD entry and it 477e11f8b7bSRoss Zwisler * collided with a PTE sized entry at a different 478e11f8b7bSRoss Zwisler * index in the PMD range. We haven't inserted 479e11f8b7bSRoss Zwisler * anything into the radix tree and have no waiters to 480e11f8b7bSRoss Zwisler * wake. 481642261acSRoss Zwisler */ 482ac401cc7SJan Kara return ERR_PTR(err); 483ac401cc7SJan Kara } 484ac401cc7SJan Kara /* Good, we have inserted empty locked entry into the tree. */ 485ac401cc7SJan Kara mapping->nrexceptional++; 486b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 487e3ad61c6SRoss Zwisler return entry; 488ac401cc7SJan Kara } 489e3ad61c6SRoss Zwisler entry = lock_slot(mapping, slot); 490642261acSRoss Zwisler out_unlock: 491b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 492e3ad61c6SRoss Zwisler return entry; 493ac401cc7SJan Kara } 494ac401cc7SJan Kara 495c6dcf52cSJan Kara static int __dax_invalidate_mapping_entry(struct address_space *mapping, 496c6dcf52cSJan Kara pgoff_t index, bool trunc) 497c6dcf52cSJan Kara { 498c6dcf52cSJan Kara int ret = 0; 499c6dcf52cSJan Kara void *entry; 500b93b0163SMatthew Wilcox struct radix_tree_root *pages = &mapping->i_pages; 501c6dcf52cSJan Kara 502b93b0163SMatthew Wilcox xa_lock_irq(pages); 503c6dcf52cSJan Kara entry = get_unlocked_mapping_entry(mapping, index, NULL); 50491d25ba8SRoss Zwisler if (!entry || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry))) 505c6dcf52cSJan Kara goto out; 506c6dcf52cSJan Kara if (!trunc && 507b93b0163SMatthew Wilcox (radix_tree_tag_get(pages, index, PAGECACHE_TAG_DIRTY) || 508b93b0163SMatthew Wilcox radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE))) 509c6dcf52cSJan Kara goto out; 510d2c997c0SDan Williams dax_disassociate_entry(entry, mapping, trunc); 511b93b0163SMatthew Wilcox radix_tree_delete(pages, index); 512c6dcf52cSJan Kara mapping->nrexceptional--; 513c6dcf52cSJan Kara ret = 1; 514c6dcf52cSJan Kara out: 515c6dcf52cSJan Kara put_unlocked_mapping_entry(mapping, index, entry); 516b93b0163SMatthew Wilcox xa_unlock_irq(pages); 517c6dcf52cSJan Kara return ret; 518c6dcf52cSJan Kara } 519ac401cc7SJan Kara /* 520ac401cc7SJan Kara * Delete exceptional DAX entry at @index from @mapping. Wait for radix tree 521ac401cc7SJan Kara * entry to get unlocked before deleting it. 522ac401cc7SJan Kara */ 523ac401cc7SJan Kara int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) 524ac401cc7SJan Kara { 525c6dcf52cSJan Kara int ret = __dax_invalidate_mapping_entry(mapping, index, true); 526ac401cc7SJan Kara 527ac401cc7SJan Kara /* 528ac401cc7SJan Kara * This gets called from truncate / punch_hole path. As such, the caller 529ac401cc7SJan Kara * must hold locks protecting against concurrent modifications of the 530ac401cc7SJan Kara * radix tree (usually fs-private i_mmap_sem for writing). Since the 531ac401cc7SJan Kara * caller has seen exceptional entry for this index, we better find it 532ac401cc7SJan Kara * at that index as well... 533ac401cc7SJan Kara */ 534c6dcf52cSJan Kara WARN_ON_ONCE(!ret); 535c6dcf52cSJan Kara return ret; 536ac401cc7SJan Kara } 537ac401cc7SJan Kara 538c6dcf52cSJan Kara /* 539c6dcf52cSJan Kara * Invalidate exceptional DAX entry if it is clean. 540c6dcf52cSJan Kara */ 541c6dcf52cSJan Kara int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 542c6dcf52cSJan Kara pgoff_t index) 543c6dcf52cSJan Kara { 544c6dcf52cSJan Kara return __dax_invalidate_mapping_entry(mapping, index, false); 545ac401cc7SJan Kara } 546ac401cc7SJan Kara 547cccbce67SDan Williams static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, 548cccbce67SDan Williams sector_t sector, size_t size, struct page *to, 549cccbce67SDan Williams unsigned long vaddr) 550f7ca90b1SMatthew Wilcox { 551cccbce67SDan Williams void *vto, *kaddr; 552cccbce67SDan Williams pgoff_t pgoff; 553cccbce67SDan Williams pfn_t pfn; 554cccbce67SDan Williams long rc; 555cccbce67SDan Williams int id; 556e2e05394SRoss Zwisler 557cccbce67SDan Williams rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); 558cccbce67SDan Williams if (rc) 559cccbce67SDan Williams return rc; 560cccbce67SDan Williams 561cccbce67SDan Williams id = dax_read_lock(); 562cccbce67SDan Williams rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); 563cccbce67SDan Williams if (rc < 0) { 564cccbce67SDan Williams dax_read_unlock(id); 565cccbce67SDan Williams return rc; 566cccbce67SDan Williams } 567f7ca90b1SMatthew Wilcox vto = kmap_atomic(to); 568cccbce67SDan Williams copy_user_page(vto, (void __force *)kaddr, vaddr, to); 569f7ca90b1SMatthew Wilcox kunmap_atomic(vto); 570cccbce67SDan Williams dax_read_unlock(id); 571f7ca90b1SMatthew Wilcox return 0; 572f7ca90b1SMatthew Wilcox } 573f7ca90b1SMatthew Wilcox 574642261acSRoss Zwisler /* 575642261acSRoss Zwisler * By this point grab_mapping_entry() has ensured that we have a locked entry 576642261acSRoss Zwisler * of the appropriate size so we don't have to worry about downgrading PMDs to 577642261acSRoss Zwisler * PTEs. If we happen to be trying to insert a PTE and there is a PMD 578642261acSRoss Zwisler * already in the tree, we will skip the insertion and just dirty the PMD as 579642261acSRoss Zwisler * appropriate. 580642261acSRoss Zwisler */ 581ac401cc7SJan Kara static void *dax_insert_mapping_entry(struct address_space *mapping, 582ac401cc7SJan Kara struct vm_fault *vmf, 5833fe0791cSDan Williams void *entry, pfn_t pfn_t, 584f5b7b748SJan Kara unsigned long flags, bool dirty) 5859973c98eSRoss Zwisler { 586b93b0163SMatthew Wilcox struct radix_tree_root *pages = &mapping->i_pages; 5873fe0791cSDan Williams unsigned long pfn = pfn_t_to_pfn(pfn_t); 588ac401cc7SJan Kara pgoff_t index = vmf->pgoff; 5893fe0791cSDan Williams void *new_entry; 5909973c98eSRoss Zwisler 591f5b7b748SJan Kara if (dirty) 5929973c98eSRoss Zwisler __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); 5939973c98eSRoss Zwisler 59491d25ba8SRoss Zwisler if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_ZERO_PAGE)) { 59591d25ba8SRoss Zwisler /* we are replacing a zero page with block mapping */ 59691d25ba8SRoss Zwisler if (dax_is_pmd_entry(entry)) 597977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, 598977fbdcdSMatthew Wilcox PG_PMD_NR, false); 59991d25ba8SRoss Zwisler else /* pte entry */ 600977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, vmf->pgoff, 1, false); 601ac401cc7SJan Kara } 6029973c98eSRoss Zwisler 603b93b0163SMatthew Wilcox xa_lock_irq(pages); 6043fe0791cSDan Williams new_entry = dax_radix_locked_entry(pfn, flags); 605d2c997c0SDan Williams if (dax_entry_size(entry) != dax_entry_size(new_entry)) { 606d2c997c0SDan Williams dax_disassociate_entry(entry, mapping, false); 607d2c997c0SDan Williams dax_associate_entry(new_entry, mapping); 608d2c997c0SDan Williams } 609642261acSRoss Zwisler 61091d25ba8SRoss Zwisler if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { 611642261acSRoss Zwisler /* 612642261acSRoss Zwisler * Only swap our new entry into the radix tree if the current 613642261acSRoss Zwisler * entry is a zero page or an empty entry. If a normal PTE or 614642261acSRoss Zwisler * PMD entry is already in the tree, we leave it alone. This 615642261acSRoss Zwisler * means that if we are trying to insert a PTE and the 616642261acSRoss Zwisler * existing entry is a PMD, we will just leave the PMD in the 617642261acSRoss Zwisler * tree and dirty it if necessary. 618642261acSRoss Zwisler */ 619f7942430SJohannes Weiner struct radix_tree_node *node; 620ac401cc7SJan Kara void **slot; 621ac401cc7SJan Kara void *ret; 622ac401cc7SJan Kara 623b93b0163SMatthew Wilcox ret = __radix_tree_lookup(pages, index, &node, &slot); 624ac401cc7SJan Kara WARN_ON_ONCE(ret != entry); 625b93b0163SMatthew Wilcox __radix_tree_replace(pages, node, slot, 626c7df8ad2SMel Gorman new_entry, NULL); 62791d25ba8SRoss Zwisler entry = new_entry; 628ac401cc7SJan Kara } 62991d25ba8SRoss Zwisler 630f5b7b748SJan Kara if (dirty) 631b93b0163SMatthew Wilcox radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY); 63291d25ba8SRoss Zwisler 633b93b0163SMatthew Wilcox xa_unlock_irq(pages); 63491d25ba8SRoss Zwisler return entry; 6359973c98eSRoss Zwisler } 6369973c98eSRoss Zwisler 6374b4bb46dSJan Kara static inline unsigned long 6384b4bb46dSJan Kara pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) 6394b4bb46dSJan Kara { 6404b4bb46dSJan Kara unsigned long address; 6414b4bb46dSJan Kara 6424b4bb46dSJan Kara address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); 6434b4bb46dSJan Kara VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); 6444b4bb46dSJan Kara return address; 6454b4bb46dSJan Kara } 6464b4bb46dSJan Kara 6474b4bb46dSJan Kara /* Walk all mappings of a given index of a file and writeprotect them */ 6484b4bb46dSJan Kara static void dax_mapping_entry_mkclean(struct address_space *mapping, 6494b4bb46dSJan Kara pgoff_t index, unsigned long pfn) 6504b4bb46dSJan Kara { 6514b4bb46dSJan Kara struct vm_area_struct *vma; 652f729c8c9SRoss Zwisler pte_t pte, *ptep = NULL; 653f729c8c9SRoss Zwisler pmd_t *pmdp = NULL; 6544b4bb46dSJan Kara spinlock_t *ptl; 6554b4bb46dSJan Kara 6564b4bb46dSJan Kara i_mmap_lock_read(mapping); 6574b4bb46dSJan Kara vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { 658a4d1a885SJérôme Glisse unsigned long address, start, end; 6594b4bb46dSJan Kara 6604b4bb46dSJan Kara cond_resched(); 6614b4bb46dSJan Kara 6624b4bb46dSJan Kara if (!(vma->vm_flags & VM_SHARED)) 6634b4bb46dSJan Kara continue; 6644b4bb46dSJan Kara 6654b4bb46dSJan Kara address = pgoff_address(index, vma); 666a4d1a885SJérôme Glisse 667a4d1a885SJérôme Glisse /* 668a4d1a885SJérôme Glisse * Note because we provide start/end to follow_pte_pmd it will 669a4d1a885SJérôme Glisse * call mmu_notifier_invalidate_range_start() on our behalf 670a4d1a885SJérôme Glisse * before taking any lock. 671a4d1a885SJérôme Glisse */ 672a4d1a885SJérôme Glisse if (follow_pte_pmd(vma->vm_mm, address, &start, &end, &ptep, &pmdp, &ptl)) 6734b4bb46dSJan Kara continue; 674f729c8c9SRoss Zwisler 6750f10851eSJérôme Glisse /* 6760f10851eSJérôme Glisse * No need to call mmu_notifier_invalidate_range() as we are 6770f10851eSJérôme Glisse * downgrading page table protection not changing it to point 6780f10851eSJérôme Glisse * to a new page. 6790f10851eSJérôme Glisse * 6800f10851eSJérôme Glisse * See Documentation/vm/mmu_notifier.txt 6810f10851eSJérôme Glisse */ 682f729c8c9SRoss Zwisler if (pmdp) { 683f729c8c9SRoss Zwisler #ifdef CONFIG_FS_DAX_PMD 684f729c8c9SRoss Zwisler pmd_t pmd; 685f729c8c9SRoss Zwisler 686f729c8c9SRoss Zwisler if (pfn != pmd_pfn(*pmdp)) 687f729c8c9SRoss Zwisler goto unlock_pmd; 688f6f37321SLinus Torvalds if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) 689f729c8c9SRoss Zwisler goto unlock_pmd; 690f729c8c9SRoss Zwisler 691f729c8c9SRoss Zwisler flush_cache_page(vma, address, pfn); 692f729c8c9SRoss Zwisler pmd = pmdp_huge_clear_flush(vma, address, pmdp); 693f729c8c9SRoss Zwisler pmd = pmd_wrprotect(pmd); 694f729c8c9SRoss Zwisler pmd = pmd_mkclean(pmd); 695f729c8c9SRoss Zwisler set_pmd_at(vma->vm_mm, address, pmdp, pmd); 696f729c8c9SRoss Zwisler unlock_pmd: 697f729c8c9SRoss Zwisler #endif 698ee190ca6SJan H. Schönherr spin_unlock(ptl); 699f729c8c9SRoss Zwisler } else { 7004b4bb46dSJan Kara if (pfn != pte_pfn(*ptep)) 701f729c8c9SRoss Zwisler goto unlock_pte; 7024b4bb46dSJan Kara if (!pte_dirty(*ptep) && !pte_write(*ptep)) 703f729c8c9SRoss Zwisler goto unlock_pte; 7044b4bb46dSJan Kara 7054b4bb46dSJan Kara flush_cache_page(vma, address, pfn); 7064b4bb46dSJan Kara pte = ptep_clear_flush(vma, address, ptep); 7074b4bb46dSJan Kara pte = pte_wrprotect(pte); 7084b4bb46dSJan Kara pte = pte_mkclean(pte); 7094b4bb46dSJan Kara set_pte_at(vma->vm_mm, address, ptep, pte); 710f729c8c9SRoss Zwisler unlock_pte: 7114b4bb46dSJan Kara pte_unmap_unlock(ptep, ptl); 712f729c8c9SRoss Zwisler } 7134b4bb46dSJan Kara 714a4d1a885SJérôme Glisse mmu_notifier_invalidate_range_end(vma->vm_mm, start, end); 7154b4bb46dSJan Kara } 7164b4bb46dSJan Kara i_mmap_unlock_read(mapping); 7174b4bb46dSJan Kara } 7184b4bb46dSJan Kara 7193fe0791cSDan Williams static int dax_writeback_one(struct dax_device *dax_dev, 7203fe0791cSDan Williams struct address_space *mapping, pgoff_t index, void *entry) 7219973c98eSRoss Zwisler { 722b93b0163SMatthew Wilcox struct radix_tree_root *pages = &mapping->i_pages; 7233fe0791cSDan Williams void *entry2, **slot; 7243fe0791cSDan Williams unsigned long pfn; 7253fe0791cSDan Williams long ret = 0; 726cccbce67SDan Williams size_t size; 7279973c98eSRoss Zwisler 7289973c98eSRoss Zwisler /* 729a6abc2c0SJan Kara * A page got tagged dirty in DAX mapping? Something is seriously 730a6abc2c0SJan Kara * wrong. 7319973c98eSRoss Zwisler */ 732a6abc2c0SJan Kara if (WARN_ON(!radix_tree_exceptional_entry(entry))) 733a6abc2c0SJan Kara return -EIO; 7349973c98eSRoss Zwisler 735b93b0163SMatthew Wilcox xa_lock_irq(pages); 736a6abc2c0SJan Kara entry2 = get_unlocked_mapping_entry(mapping, index, &slot); 737a6abc2c0SJan Kara /* Entry got punched out / reallocated? */ 73891d25ba8SRoss Zwisler if (!entry2 || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry2))) 739a6abc2c0SJan Kara goto put_unlocked; 740a6abc2c0SJan Kara /* 741a6abc2c0SJan Kara * Entry got reallocated elsewhere? No need to writeback. We have to 7423fe0791cSDan Williams * compare pfns as we must not bail out due to difference in lockbit 743a6abc2c0SJan Kara * or entry type. 744a6abc2c0SJan Kara */ 7453fe0791cSDan Williams if (dax_radix_pfn(entry2) != dax_radix_pfn(entry)) 746a6abc2c0SJan Kara goto put_unlocked; 747642261acSRoss Zwisler if (WARN_ON_ONCE(dax_is_empty_entry(entry) || 748642261acSRoss Zwisler dax_is_zero_entry(entry))) { 7499973c98eSRoss Zwisler ret = -EIO; 750a6abc2c0SJan Kara goto put_unlocked; 7519973c98eSRoss Zwisler } 7529973c98eSRoss Zwisler 753a6abc2c0SJan Kara /* Another fsync thread may have already written back this entry */ 754b93b0163SMatthew Wilcox if (!radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE)) 755a6abc2c0SJan Kara goto put_unlocked; 756a6abc2c0SJan Kara /* Lock the entry to serialize with page faults */ 757a6abc2c0SJan Kara entry = lock_slot(mapping, slot); 758a6abc2c0SJan Kara /* 759a6abc2c0SJan Kara * We can clear the tag now but we have to be careful so that concurrent 760a6abc2c0SJan Kara * dax_writeback_one() calls for the same index cannot finish before we 761a6abc2c0SJan Kara * actually flush the caches. This is achieved as the calls will look 762b93b0163SMatthew Wilcox * at the entry only under the i_pages lock and once they do that 763b93b0163SMatthew Wilcox * they will see the entry locked and wait for it to unlock. 764a6abc2c0SJan Kara */ 765b93b0163SMatthew Wilcox radix_tree_tag_clear(pages, index, PAGECACHE_TAG_TOWRITE); 766b93b0163SMatthew Wilcox xa_unlock_irq(pages); 767a6abc2c0SJan Kara 768642261acSRoss Zwisler /* 769642261acSRoss Zwisler * Even if dax_writeback_mapping_range() was given a wbc->range_start 770642261acSRoss Zwisler * in the middle of a PMD, the 'index' we are given will be aligned to 7713fe0791cSDan Williams * the start index of the PMD, as will the pfn we pull from 'entry'. 7723fe0791cSDan Williams * This allows us to flush for PMD_SIZE and not have to worry about 7733fe0791cSDan Williams * partial PMD writebacks. 774642261acSRoss Zwisler */ 7753fe0791cSDan Williams pfn = dax_radix_pfn(entry); 776cccbce67SDan Williams size = PAGE_SIZE << dax_radix_order(entry); 777cccbce67SDan Williams 7783fe0791cSDan Williams dax_mapping_entry_mkclean(mapping, index, pfn); 7793fe0791cSDan Williams dax_flush(dax_dev, page_address(pfn_to_page(pfn)), size); 7804b4bb46dSJan Kara /* 7814b4bb46dSJan Kara * After we have flushed the cache, we can clear the dirty tag. There 7824b4bb46dSJan Kara * cannot be new dirty data in the pfn after the flush has completed as 7834b4bb46dSJan Kara * the pfn mappings are writeprotected and fault waits for mapping 7844b4bb46dSJan Kara * entry lock. 7854b4bb46dSJan Kara */ 786b93b0163SMatthew Wilcox xa_lock_irq(pages); 787b93b0163SMatthew Wilcox radix_tree_tag_clear(pages, index, PAGECACHE_TAG_DIRTY); 788b93b0163SMatthew Wilcox xa_unlock_irq(pages); 789f9bc3a07SRoss Zwisler trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT); 79091d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, index); 7919973c98eSRoss Zwisler return ret; 7929973c98eSRoss Zwisler 793a6abc2c0SJan Kara put_unlocked: 794a6abc2c0SJan Kara put_unlocked_mapping_entry(mapping, index, entry2); 795b93b0163SMatthew Wilcox xa_unlock_irq(pages); 7969973c98eSRoss Zwisler return ret; 7979973c98eSRoss Zwisler } 7989973c98eSRoss Zwisler 7999973c98eSRoss Zwisler /* 8009973c98eSRoss Zwisler * Flush the mapping to the persistent domain within the byte range of [start, 8019973c98eSRoss Zwisler * end]. This is required by data integrity operations to ensure file data is 8029973c98eSRoss Zwisler * on persistent storage prior to completion of the operation. 8039973c98eSRoss Zwisler */ 8047f6d5b52SRoss Zwisler int dax_writeback_mapping_range(struct address_space *mapping, 8057f6d5b52SRoss Zwisler struct block_device *bdev, struct writeback_control *wbc) 8069973c98eSRoss Zwisler { 8079973c98eSRoss Zwisler struct inode *inode = mapping->host; 808642261acSRoss Zwisler pgoff_t start_index, end_index; 8099973c98eSRoss Zwisler pgoff_t indices[PAGEVEC_SIZE]; 810cccbce67SDan Williams struct dax_device *dax_dev; 8119973c98eSRoss Zwisler struct pagevec pvec; 8129973c98eSRoss Zwisler bool done = false; 8139973c98eSRoss Zwisler int i, ret = 0; 8149973c98eSRoss Zwisler 8159973c98eSRoss Zwisler if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) 8169973c98eSRoss Zwisler return -EIO; 8179973c98eSRoss Zwisler 8187f6d5b52SRoss Zwisler if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) 8197f6d5b52SRoss Zwisler return 0; 8207f6d5b52SRoss Zwisler 821cccbce67SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 822cccbce67SDan Williams if (!dax_dev) 823cccbce67SDan Williams return -EIO; 824cccbce67SDan Williams 82509cbfeafSKirill A. Shutemov start_index = wbc->range_start >> PAGE_SHIFT; 82609cbfeafSKirill A. Shutemov end_index = wbc->range_end >> PAGE_SHIFT; 8279973c98eSRoss Zwisler 828d14a3f48SRoss Zwisler trace_dax_writeback_range(inode, start_index, end_index); 829d14a3f48SRoss Zwisler 8309973c98eSRoss Zwisler tag_pages_for_writeback(mapping, start_index, end_index); 8319973c98eSRoss Zwisler 83286679820SMel Gorman pagevec_init(&pvec); 8339973c98eSRoss Zwisler while (!done) { 8349973c98eSRoss Zwisler pvec.nr = find_get_entries_tag(mapping, start_index, 8359973c98eSRoss Zwisler PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, 8369973c98eSRoss Zwisler pvec.pages, indices); 8379973c98eSRoss Zwisler 8389973c98eSRoss Zwisler if (pvec.nr == 0) 8399973c98eSRoss Zwisler break; 8409973c98eSRoss Zwisler 8419973c98eSRoss Zwisler for (i = 0; i < pvec.nr; i++) { 8429973c98eSRoss Zwisler if (indices[i] > end_index) { 8439973c98eSRoss Zwisler done = true; 8449973c98eSRoss Zwisler break; 8459973c98eSRoss Zwisler } 8469973c98eSRoss Zwisler 8473fe0791cSDan Williams ret = dax_writeback_one(dax_dev, mapping, indices[i], 8483fe0791cSDan Williams pvec.pages[i]); 849819ec6b9SJeff Layton if (ret < 0) { 850819ec6b9SJeff Layton mapping_set_error(mapping, ret); 851d14a3f48SRoss Zwisler goto out; 852d14a3f48SRoss Zwisler } 853d14a3f48SRoss Zwisler } 8541eb643d0SJan Kara start_index = indices[pvec.nr - 1] + 1; 855d14a3f48SRoss Zwisler } 856d14a3f48SRoss Zwisler out: 857cccbce67SDan Williams put_dax(dax_dev); 858d14a3f48SRoss Zwisler trace_dax_writeback_range_done(inode, start_index, end_index); 859d14a3f48SRoss Zwisler return (ret < 0 ? ret : 0); 8609973c98eSRoss Zwisler } 8619973c98eSRoss Zwisler EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); 8629973c98eSRoss Zwisler 86331a6f1a6SJan Kara static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) 864f7ca90b1SMatthew Wilcox { 865a3841f94SLinus Torvalds return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9; 86631a6f1a6SJan Kara } 867f7ca90b1SMatthew Wilcox 8685e161e40SJan Kara static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size, 8695e161e40SJan Kara pfn_t *pfnp) 8705e161e40SJan Kara { 8715e161e40SJan Kara const sector_t sector = dax_iomap_sector(iomap, pos); 8725e161e40SJan Kara pgoff_t pgoff; 8735e161e40SJan Kara void *kaddr; 8745e161e40SJan Kara int id, rc; 8755e161e40SJan Kara long length; 8765e161e40SJan Kara 8775e161e40SJan Kara rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff); 878cccbce67SDan Williams if (rc) 879cccbce67SDan Williams return rc; 880cccbce67SDan Williams id = dax_read_lock(); 8815e161e40SJan Kara length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), 8825e161e40SJan Kara &kaddr, pfnp); 8835e161e40SJan Kara if (length < 0) { 8845e161e40SJan Kara rc = length; 8855e161e40SJan Kara goto out; 8865e161e40SJan Kara } 8875e161e40SJan Kara rc = -EINVAL; 8885e161e40SJan Kara if (PFN_PHYS(length) < size) 8895e161e40SJan Kara goto out; 8905e161e40SJan Kara if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) 8915e161e40SJan Kara goto out; 8925e161e40SJan Kara /* For larger pages we need devmap */ 8935e161e40SJan Kara if (length > 1 && !pfn_t_devmap(*pfnp)) 8945e161e40SJan Kara goto out; 8955e161e40SJan Kara rc = 0; 8965e161e40SJan Kara out: 897cccbce67SDan Williams dax_read_unlock(id); 898cccbce67SDan Williams return rc; 899cccbce67SDan Williams } 900f7ca90b1SMatthew Wilcox 9012f89dc12SJan Kara /* 90291d25ba8SRoss Zwisler * The user has performed a load from a hole in the file. Allocating a new 90391d25ba8SRoss Zwisler * page in the file would cause excessive storage usage for workloads with 90491d25ba8SRoss Zwisler * sparse files. Instead we insert a read-only mapping of the 4k zero page. 90591d25ba8SRoss Zwisler * If this page is ever written to we will re-fault and change the mapping to 90691d25ba8SRoss Zwisler * point to real DAX storage instead. 9072f89dc12SJan Kara */ 90891d25ba8SRoss Zwisler static int dax_load_hole(struct address_space *mapping, void *entry, 909e30331ffSRoss Zwisler struct vm_fault *vmf) 910e30331ffSRoss Zwisler { 911e30331ffSRoss Zwisler struct inode *inode = mapping->host; 91291d25ba8SRoss Zwisler unsigned long vaddr = vmf->address; 91391d25ba8SRoss Zwisler int ret = VM_FAULT_NOPAGE; 91491d25ba8SRoss Zwisler struct page *zero_page; 91591d25ba8SRoss Zwisler void *entry2; 9163fe0791cSDan Williams pfn_t pfn; 917e30331ffSRoss Zwisler 91891d25ba8SRoss Zwisler zero_page = ZERO_PAGE(0); 91991d25ba8SRoss Zwisler if (unlikely(!zero_page)) { 920e30331ffSRoss Zwisler ret = VM_FAULT_OOM; 921e30331ffSRoss Zwisler goto out; 922e30331ffSRoss Zwisler } 923e30331ffSRoss Zwisler 9243fe0791cSDan Williams pfn = page_to_pfn_t(zero_page); 9253fe0791cSDan Williams entry2 = dax_insert_mapping_entry(mapping, vmf, entry, pfn, 926f5b7b748SJan Kara RADIX_DAX_ZERO_PAGE, false); 92791d25ba8SRoss Zwisler if (IS_ERR(entry2)) { 92891d25ba8SRoss Zwisler ret = VM_FAULT_SIGBUS; 92991d25ba8SRoss Zwisler goto out; 930e30331ffSRoss Zwisler } 93191d25ba8SRoss Zwisler 9323fe0791cSDan Williams vm_insert_mixed(vmf->vma, vaddr, pfn); 933e30331ffSRoss Zwisler out: 934e30331ffSRoss Zwisler trace_dax_load_hole(inode, vmf, ret); 935e30331ffSRoss Zwisler return ret; 936e30331ffSRoss Zwisler } 937e30331ffSRoss Zwisler 9384b0228faSVishal Verma static bool dax_range_is_aligned(struct block_device *bdev, 9394b0228faSVishal Verma unsigned int offset, unsigned int length) 9404b0228faSVishal Verma { 9414b0228faSVishal Verma unsigned short sector_size = bdev_logical_block_size(bdev); 9424b0228faSVishal Verma 9434b0228faSVishal Verma if (!IS_ALIGNED(offset, sector_size)) 9444b0228faSVishal Verma return false; 9454b0228faSVishal Verma if (!IS_ALIGNED(length, sector_size)) 9464b0228faSVishal Verma return false; 9474b0228faSVishal Verma 9484b0228faSVishal Verma return true; 9494b0228faSVishal Verma } 9504b0228faSVishal Verma 951cccbce67SDan Williams int __dax_zero_page_range(struct block_device *bdev, 952cccbce67SDan Williams struct dax_device *dax_dev, sector_t sector, 953cccbce67SDan Williams unsigned int offset, unsigned int size) 954679c8bd3SChristoph Hellwig { 955cccbce67SDan Williams if (dax_range_is_aligned(bdev, offset, size)) { 956cccbce67SDan Williams sector_t start_sector = sector + (offset >> 9); 9574b0228faSVishal Verma 9584b0228faSVishal Verma return blkdev_issue_zeroout(bdev, start_sector, 95953ef7d0eSLinus Torvalds size >> 9, GFP_NOFS, 0); 9604b0228faSVishal Verma } else { 961cccbce67SDan Williams pgoff_t pgoff; 962cccbce67SDan Williams long rc, id; 963cccbce67SDan Williams void *kaddr; 964cccbce67SDan Williams pfn_t pfn; 965cccbce67SDan Williams 966e84b83b9SDan Williams rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff); 967cccbce67SDan Williams if (rc) 968cccbce67SDan Williams return rc; 969cccbce67SDan Williams 970cccbce67SDan Williams id = dax_read_lock(); 971e84b83b9SDan Williams rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, 972cccbce67SDan Williams &pfn); 973cccbce67SDan Williams if (rc < 0) { 974cccbce67SDan Williams dax_read_unlock(id); 975cccbce67SDan Williams return rc; 976cccbce67SDan Williams } 97781f55870SDan Williams memset(kaddr + offset, 0, size); 978c3ca015fSMikulas Patocka dax_flush(dax_dev, kaddr + offset, size); 979cccbce67SDan Williams dax_read_unlock(id); 9804b0228faSVishal Verma } 981679c8bd3SChristoph Hellwig return 0; 982679c8bd3SChristoph Hellwig } 983679c8bd3SChristoph Hellwig EXPORT_SYMBOL_GPL(__dax_zero_page_range); 984679c8bd3SChristoph Hellwig 985a254e568SChristoph Hellwig static loff_t 98611c59c92SRoss Zwisler dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, 987a254e568SChristoph Hellwig struct iomap *iomap) 988a254e568SChristoph Hellwig { 989cccbce67SDan Williams struct block_device *bdev = iomap->bdev; 990cccbce67SDan Williams struct dax_device *dax_dev = iomap->dax_dev; 991a254e568SChristoph Hellwig struct iov_iter *iter = data; 992a254e568SChristoph Hellwig loff_t end = pos + length, done = 0; 993a254e568SChristoph Hellwig ssize_t ret = 0; 994cccbce67SDan Williams int id; 995a254e568SChristoph Hellwig 996a254e568SChristoph Hellwig if (iov_iter_rw(iter) == READ) { 997a254e568SChristoph Hellwig end = min(end, i_size_read(inode)); 998a254e568SChristoph Hellwig if (pos >= end) 999a254e568SChristoph Hellwig return 0; 1000a254e568SChristoph Hellwig 1001a254e568SChristoph Hellwig if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) 1002a254e568SChristoph Hellwig return iov_iter_zero(min(length, end - pos), iter); 1003a254e568SChristoph Hellwig } 1004a254e568SChristoph Hellwig 1005a254e568SChristoph Hellwig if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) 1006a254e568SChristoph Hellwig return -EIO; 1007a254e568SChristoph Hellwig 1008e3fce68cSJan Kara /* 1009e3fce68cSJan Kara * Write can allocate block for an area which has a hole page mapped 1010e3fce68cSJan Kara * into page tables. We have to tear down these mappings so that data 1011e3fce68cSJan Kara * written by write(2) is visible in mmap. 1012e3fce68cSJan Kara */ 1013cd656375SJan Kara if (iomap->flags & IOMAP_F_NEW) { 1014e3fce68cSJan Kara invalidate_inode_pages2_range(inode->i_mapping, 1015e3fce68cSJan Kara pos >> PAGE_SHIFT, 1016e3fce68cSJan Kara (end - 1) >> PAGE_SHIFT); 1017e3fce68cSJan Kara } 1018e3fce68cSJan Kara 1019cccbce67SDan Williams id = dax_read_lock(); 1020a254e568SChristoph Hellwig while (pos < end) { 1021a254e568SChristoph Hellwig unsigned offset = pos & (PAGE_SIZE - 1); 1022cccbce67SDan Williams const size_t size = ALIGN(length + offset, PAGE_SIZE); 1023cccbce67SDan Williams const sector_t sector = dax_iomap_sector(iomap, pos); 1024a254e568SChristoph Hellwig ssize_t map_len; 1025cccbce67SDan Williams pgoff_t pgoff; 1026cccbce67SDan Williams void *kaddr; 1027cccbce67SDan Williams pfn_t pfn; 1028a254e568SChristoph Hellwig 1029d1908f52SMichal Hocko if (fatal_signal_pending(current)) { 1030d1908f52SMichal Hocko ret = -EINTR; 1031d1908f52SMichal Hocko break; 1032d1908f52SMichal Hocko } 1033d1908f52SMichal Hocko 1034cccbce67SDan Williams ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); 1035cccbce67SDan Williams if (ret) 1036cccbce67SDan Williams break; 1037cccbce67SDan Williams 1038cccbce67SDan Williams map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), 1039cccbce67SDan Williams &kaddr, &pfn); 1040a254e568SChristoph Hellwig if (map_len < 0) { 1041a254e568SChristoph Hellwig ret = map_len; 1042a254e568SChristoph Hellwig break; 1043a254e568SChristoph Hellwig } 1044a254e568SChristoph Hellwig 1045cccbce67SDan Williams map_len = PFN_PHYS(map_len); 1046cccbce67SDan Williams kaddr += offset; 1047a254e568SChristoph Hellwig map_len -= offset; 1048a254e568SChristoph Hellwig if (map_len > end - pos) 1049a254e568SChristoph Hellwig map_len = end - pos; 1050a254e568SChristoph Hellwig 1051a2e050f5SRoss Zwisler /* 1052a2e050f5SRoss Zwisler * The userspace address for the memory copy has already been 1053a2e050f5SRoss Zwisler * validated via access_ok() in either vfs_read() or 1054a2e050f5SRoss Zwisler * vfs_write(), depending on which operation we are doing. 1055a2e050f5SRoss Zwisler */ 1056a254e568SChristoph Hellwig if (iov_iter_rw(iter) == WRITE) 1057fec53774SDan Williams map_len = dax_copy_from_iter(dax_dev, pgoff, kaddr, 1058fec53774SDan Williams map_len, iter); 1059a254e568SChristoph Hellwig else 1060b3a9a0c3SDan Williams map_len = dax_copy_to_iter(dax_dev, pgoff, kaddr, 1061b3a9a0c3SDan Williams map_len, iter); 1062a254e568SChristoph Hellwig if (map_len <= 0) { 1063a254e568SChristoph Hellwig ret = map_len ? map_len : -EFAULT; 1064a254e568SChristoph Hellwig break; 1065a254e568SChristoph Hellwig } 1066a254e568SChristoph Hellwig 1067a254e568SChristoph Hellwig pos += map_len; 1068a254e568SChristoph Hellwig length -= map_len; 1069a254e568SChristoph Hellwig done += map_len; 1070a254e568SChristoph Hellwig } 1071cccbce67SDan Williams dax_read_unlock(id); 1072a254e568SChristoph Hellwig 1073a254e568SChristoph Hellwig return done ? done : ret; 1074a254e568SChristoph Hellwig } 1075a254e568SChristoph Hellwig 1076a254e568SChristoph Hellwig /** 107711c59c92SRoss Zwisler * dax_iomap_rw - Perform I/O to a DAX file 1078a254e568SChristoph Hellwig * @iocb: The control block for this I/O 1079a254e568SChristoph Hellwig * @iter: The addresses to do I/O from or to 1080a254e568SChristoph Hellwig * @ops: iomap ops passed from the file system 1081a254e568SChristoph Hellwig * 1082a254e568SChristoph Hellwig * This function performs read and write operations to directly mapped 1083a254e568SChristoph Hellwig * persistent memory. The callers needs to take care of read/write exclusion 1084a254e568SChristoph Hellwig * and evicting any page cache pages in the region under I/O. 1085a254e568SChristoph Hellwig */ 1086a254e568SChristoph Hellwig ssize_t 108711c59c92SRoss Zwisler dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 10888ff6daa1SChristoph Hellwig const struct iomap_ops *ops) 1089a254e568SChristoph Hellwig { 1090a254e568SChristoph Hellwig struct address_space *mapping = iocb->ki_filp->f_mapping; 1091a254e568SChristoph Hellwig struct inode *inode = mapping->host; 1092a254e568SChristoph Hellwig loff_t pos = iocb->ki_pos, ret = 0, done = 0; 1093a254e568SChristoph Hellwig unsigned flags = 0; 1094a254e568SChristoph Hellwig 1095168316dbSChristoph Hellwig if (iov_iter_rw(iter) == WRITE) { 1096168316dbSChristoph Hellwig lockdep_assert_held_exclusive(&inode->i_rwsem); 1097a254e568SChristoph Hellwig flags |= IOMAP_WRITE; 1098168316dbSChristoph Hellwig } else { 1099168316dbSChristoph Hellwig lockdep_assert_held(&inode->i_rwsem); 1100168316dbSChristoph Hellwig } 1101a254e568SChristoph Hellwig 1102a254e568SChristoph Hellwig while (iov_iter_count(iter)) { 1103a254e568SChristoph Hellwig ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, 110411c59c92SRoss Zwisler iter, dax_iomap_actor); 1105a254e568SChristoph Hellwig if (ret <= 0) 1106a254e568SChristoph Hellwig break; 1107a254e568SChristoph Hellwig pos += ret; 1108a254e568SChristoph Hellwig done += ret; 1109a254e568SChristoph Hellwig } 1110a254e568SChristoph Hellwig 1111a254e568SChristoph Hellwig iocb->ki_pos += done; 1112a254e568SChristoph Hellwig return done ? done : ret; 1113a254e568SChristoph Hellwig } 111411c59c92SRoss Zwisler EXPORT_SYMBOL_GPL(dax_iomap_rw); 1115a7d73fe6SChristoph Hellwig 11169f141d6eSJan Kara static int dax_fault_return(int error) 11179f141d6eSJan Kara { 11189f141d6eSJan Kara if (error == 0) 11199f141d6eSJan Kara return VM_FAULT_NOPAGE; 11209f141d6eSJan Kara if (error == -ENOMEM) 11219f141d6eSJan Kara return VM_FAULT_OOM; 11229f141d6eSJan Kara return VM_FAULT_SIGBUS; 11239f141d6eSJan Kara } 11249f141d6eSJan Kara 1125aaa422c4SDan Williams /* 1126aaa422c4SDan Williams * MAP_SYNC on a dax mapping guarantees dirty metadata is 1127aaa422c4SDan Williams * flushed on write-faults (non-cow), but not read-faults. 1128aaa422c4SDan Williams */ 1129aaa422c4SDan Williams static bool dax_fault_is_synchronous(unsigned long flags, 1130aaa422c4SDan Williams struct vm_area_struct *vma, struct iomap *iomap) 1131aaa422c4SDan Williams { 1132aaa422c4SDan Williams return (flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) 1133aaa422c4SDan Williams && (iomap->flags & IOMAP_F_DIRTY); 1134aaa422c4SDan Williams } 1135aaa422c4SDan Williams 11369a0dd422SJan Kara static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, 1137c0b24625SJan Kara int *iomap_errp, const struct iomap_ops *ops) 1138a7d73fe6SChristoph Hellwig { 1139a0987ad5SJan Kara struct vm_area_struct *vma = vmf->vma; 1140a0987ad5SJan Kara struct address_space *mapping = vma->vm_file->f_mapping; 1141a7d73fe6SChristoph Hellwig struct inode *inode = mapping->host; 11421a29d85eSJan Kara unsigned long vaddr = vmf->address; 1143a7d73fe6SChristoph Hellwig loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; 1144a7d73fe6SChristoph Hellwig struct iomap iomap = { 0 }; 11459484ab1bSJan Kara unsigned flags = IOMAP_FAULT; 1146a7d73fe6SChristoph Hellwig int error, major = 0; 1147d2c43ef1SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 1148caa51d26SJan Kara bool sync; 1149b1aa812bSJan Kara int vmf_ret = 0; 1150a7d73fe6SChristoph Hellwig void *entry; 11511b5a1cb2SJan Kara pfn_t pfn; 1152a7d73fe6SChristoph Hellwig 1153a9c42b33SRoss Zwisler trace_dax_pte_fault(inode, vmf, vmf_ret); 1154a7d73fe6SChristoph Hellwig /* 1155a7d73fe6SChristoph Hellwig * Check whether offset isn't beyond end of file now. Caller is supposed 1156a7d73fe6SChristoph Hellwig * to hold locks serializing us with truncate / punch hole so this is 1157a7d73fe6SChristoph Hellwig * a reliable test. 1158a7d73fe6SChristoph Hellwig */ 1159a9c42b33SRoss Zwisler if (pos >= i_size_read(inode)) { 1160a9c42b33SRoss Zwisler vmf_ret = VM_FAULT_SIGBUS; 1161a9c42b33SRoss Zwisler goto out; 1162a9c42b33SRoss Zwisler } 1163a7d73fe6SChristoph Hellwig 1164d2c43ef1SJan Kara if (write && !vmf->cow_page) 1165a7d73fe6SChristoph Hellwig flags |= IOMAP_WRITE; 1166a7d73fe6SChristoph Hellwig 116713e451fdSJan Kara entry = grab_mapping_entry(mapping, vmf->pgoff, 0); 116813e451fdSJan Kara if (IS_ERR(entry)) { 116913e451fdSJan Kara vmf_ret = dax_fault_return(PTR_ERR(entry)); 117013e451fdSJan Kara goto out; 117113e451fdSJan Kara } 117213e451fdSJan Kara 1173a7d73fe6SChristoph Hellwig /* 1174e2093926SRoss Zwisler * It is possible, particularly with mixed reads & writes to private 1175e2093926SRoss Zwisler * mappings, that we have raced with a PMD fault that overlaps with 1176e2093926SRoss Zwisler * the PTE we need to set up. If so just return and the fault will be 1177e2093926SRoss Zwisler * retried. 1178e2093926SRoss Zwisler */ 1179e2093926SRoss Zwisler if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { 1180e2093926SRoss Zwisler vmf_ret = VM_FAULT_NOPAGE; 1181e2093926SRoss Zwisler goto unlock_entry; 1182e2093926SRoss Zwisler } 1183e2093926SRoss Zwisler 1184e2093926SRoss Zwisler /* 1185a7d73fe6SChristoph Hellwig * Note that we don't bother to use iomap_apply here: DAX required 1186a7d73fe6SChristoph Hellwig * the file system block size to be equal the page size, which means 1187a7d73fe6SChristoph Hellwig * that we never have to deal with more than a single extent here. 1188a7d73fe6SChristoph Hellwig */ 1189a7d73fe6SChristoph Hellwig error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); 1190c0b24625SJan Kara if (iomap_errp) 1191c0b24625SJan Kara *iomap_errp = error; 1192a9c42b33SRoss Zwisler if (error) { 1193a9c42b33SRoss Zwisler vmf_ret = dax_fault_return(error); 119413e451fdSJan Kara goto unlock_entry; 1195a9c42b33SRoss Zwisler } 1196a7d73fe6SChristoph Hellwig if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { 119713e451fdSJan Kara error = -EIO; /* fs corruption? */ 119813e451fdSJan Kara goto error_finish_iomap; 1199a7d73fe6SChristoph Hellwig } 1200a7d73fe6SChristoph Hellwig 1201a7d73fe6SChristoph Hellwig if (vmf->cow_page) { 120231a6f1a6SJan Kara sector_t sector = dax_iomap_sector(&iomap, pos); 120331a6f1a6SJan Kara 1204a7d73fe6SChristoph Hellwig switch (iomap.type) { 1205a7d73fe6SChristoph Hellwig case IOMAP_HOLE: 1206a7d73fe6SChristoph Hellwig case IOMAP_UNWRITTEN: 1207a7d73fe6SChristoph Hellwig clear_user_highpage(vmf->cow_page, vaddr); 1208a7d73fe6SChristoph Hellwig break; 1209a7d73fe6SChristoph Hellwig case IOMAP_MAPPED: 1210cccbce67SDan Williams error = copy_user_dax(iomap.bdev, iomap.dax_dev, 1211cccbce67SDan Williams sector, PAGE_SIZE, vmf->cow_page, vaddr); 1212a7d73fe6SChristoph Hellwig break; 1213a7d73fe6SChristoph Hellwig default: 1214a7d73fe6SChristoph Hellwig WARN_ON_ONCE(1); 1215a7d73fe6SChristoph Hellwig error = -EIO; 1216a7d73fe6SChristoph Hellwig break; 1217a7d73fe6SChristoph Hellwig } 1218a7d73fe6SChristoph Hellwig 1219a7d73fe6SChristoph Hellwig if (error) 122013e451fdSJan Kara goto error_finish_iomap; 1221b1aa812bSJan Kara 1222b1aa812bSJan Kara __SetPageUptodate(vmf->cow_page); 1223b1aa812bSJan Kara vmf_ret = finish_fault(vmf); 1224b1aa812bSJan Kara if (!vmf_ret) 1225b1aa812bSJan Kara vmf_ret = VM_FAULT_DONE_COW; 122613e451fdSJan Kara goto finish_iomap; 1227a7d73fe6SChristoph Hellwig } 1228a7d73fe6SChristoph Hellwig 1229aaa422c4SDan Williams sync = dax_fault_is_synchronous(flags, vma, &iomap); 1230caa51d26SJan Kara 1231a7d73fe6SChristoph Hellwig switch (iomap.type) { 1232a7d73fe6SChristoph Hellwig case IOMAP_MAPPED: 1233a7d73fe6SChristoph Hellwig if (iomap.flags & IOMAP_F_NEW) { 1234a7d73fe6SChristoph Hellwig count_vm_event(PGMAJFAULT); 1235a0987ad5SJan Kara count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 1236a7d73fe6SChristoph Hellwig major = VM_FAULT_MAJOR; 1237a7d73fe6SChristoph Hellwig } 12381b5a1cb2SJan Kara error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); 12391b5a1cb2SJan Kara if (error < 0) 12401b5a1cb2SJan Kara goto error_finish_iomap; 12411b5a1cb2SJan Kara 12423fe0791cSDan Williams entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn, 1243caa51d26SJan Kara 0, write && !sync); 12441b5a1cb2SJan Kara if (IS_ERR(entry)) { 12451b5a1cb2SJan Kara error = PTR_ERR(entry); 12461b5a1cb2SJan Kara goto error_finish_iomap; 12471b5a1cb2SJan Kara } 12481b5a1cb2SJan Kara 1249caa51d26SJan Kara /* 1250caa51d26SJan Kara * If we are doing synchronous page fault and inode needs fsync, 1251caa51d26SJan Kara * we can insert PTE into page tables only after that happens. 1252caa51d26SJan Kara * Skip insertion for now and return the pfn so that caller can 1253caa51d26SJan Kara * insert it after fsync is done. 1254caa51d26SJan Kara */ 1255caa51d26SJan Kara if (sync) { 1256caa51d26SJan Kara if (WARN_ON_ONCE(!pfnp)) { 1257caa51d26SJan Kara error = -EIO; 1258caa51d26SJan Kara goto error_finish_iomap; 1259caa51d26SJan Kara } 1260caa51d26SJan Kara *pfnp = pfn; 1261caa51d26SJan Kara vmf_ret = VM_FAULT_NEEDDSYNC | major; 1262caa51d26SJan Kara goto finish_iomap; 1263caa51d26SJan Kara } 12641b5a1cb2SJan Kara trace_dax_insert_mapping(inode, vmf, entry); 12651b5a1cb2SJan Kara if (write) 12661b5a1cb2SJan Kara error = vm_insert_mixed_mkwrite(vma, vaddr, pfn); 12671b5a1cb2SJan Kara else 12681b5a1cb2SJan Kara error = vm_insert_mixed(vma, vaddr, pfn); 12691b5a1cb2SJan Kara 12709f141d6eSJan Kara /* -EBUSY is fine, somebody else faulted on the same PTE */ 12719f141d6eSJan Kara if (error == -EBUSY) 12729f141d6eSJan Kara error = 0; 1273a7d73fe6SChristoph Hellwig break; 1274a7d73fe6SChristoph Hellwig case IOMAP_UNWRITTEN: 1275a7d73fe6SChristoph Hellwig case IOMAP_HOLE: 1276d2c43ef1SJan Kara if (!write) { 127791d25ba8SRoss Zwisler vmf_ret = dax_load_hole(mapping, entry, vmf); 127813e451fdSJan Kara goto finish_iomap; 12791550290bSRoss Zwisler } 1280a7d73fe6SChristoph Hellwig /*FALLTHRU*/ 1281a7d73fe6SChristoph Hellwig default: 1282a7d73fe6SChristoph Hellwig WARN_ON_ONCE(1); 1283a7d73fe6SChristoph Hellwig error = -EIO; 1284a7d73fe6SChristoph Hellwig break; 1285a7d73fe6SChristoph Hellwig } 1286a7d73fe6SChristoph Hellwig 128713e451fdSJan Kara error_finish_iomap: 12889f141d6eSJan Kara vmf_ret = dax_fault_return(error) | major; 12899f141d6eSJan Kara finish_iomap: 12909f141d6eSJan Kara if (ops->iomap_end) { 12919f141d6eSJan Kara int copied = PAGE_SIZE; 12929f141d6eSJan Kara 12939f141d6eSJan Kara if (vmf_ret & VM_FAULT_ERROR) 12949f141d6eSJan Kara copied = 0; 12959f141d6eSJan Kara /* 12969f141d6eSJan Kara * The fault is done by now and there's no way back (other 12979f141d6eSJan Kara * thread may be already happily using PTE we have installed). 12989f141d6eSJan Kara * Just ignore error from ->iomap_end since we cannot do much 12999f141d6eSJan Kara * with it. 13009f141d6eSJan Kara */ 13019f141d6eSJan Kara ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); 13021550290bSRoss Zwisler } 130313e451fdSJan Kara unlock_entry: 130491d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, vmf->pgoff); 1305a9c42b33SRoss Zwisler out: 1306a9c42b33SRoss Zwisler trace_dax_pte_fault_done(inode, vmf, vmf_ret); 13079f141d6eSJan Kara return vmf_ret; 1308a7d73fe6SChristoph Hellwig } 1309642261acSRoss Zwisler 1310642261acSRoss Zwisler #ifdef CONFIG_FS_DAX_PMD 1311f4200391SDave Jiang static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, 131291d25ba8SRoss Zwisler void *entry) 1313642261acSRoss Zwisler { 1314f4200391SDave Jiang struct address_space *mapping = vmf->vma->vm_file->f_mapping; 1315f4200391SDave Jiang unsigned long pmd_addr = vmf->address & PMD_MASK; 1316653b2ea3SRoss Zwisler struct inode *inode = mapping->host; 1317642261acSRoss Zwisler struct page *zero_page; 1318653b2ea3SRoss Zwisler void *ret = NULL; 1319642261acSRoss Zwisler spinlock_t *ptl; 1320642261acSRoss Zwisler pmd_t pmd_entry; 13213fe0791cSDan Williams pfn_t pfn; 1322642261acSRoss Zwisler 1323f4200391SDave Jiang zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); 1324642261acSRoss Zwisler 1325642261acSRoss Zwisler if (unlikely(!zero_page)) 1326653b2ea3SRoss Zwisler goto fallback; 1327642261acSRoss Zwisler 13283fe0791cSDan Williams pfn = page_to_pfn_t(zero_page); 13293fe0791cSDan Williams ret = dax_insert_mapping_entry(mapping, vmf, entry, pfn, 1330f5b7b748SJan Kara RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false); 1331642261acSRoss Zwisler if (IS_ERR(ret)) 1332653b2ea3SRoss Zwisler goto fallback; 1333642261acSRoss Zwisler 1334f4200391SDave Jiang ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1335f4200391SDave Jiang if (!pmd_none(*(vmf->pmd))) { 1336642261acSRoss Zwisler spin_unlock(ptl); 1337653b2ea3SRoss Zwisler goto fallback; 1338642261acSRoss Zwisler } 1339642261acSRoss Zwisler 1340f4200391SDave Jiang pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); 1341642261acSRoss Zwisler pmd_entry = pmd_mkhuge(pmd_entry); 1342f4200391SDave Jiang set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); 1343642261acSRoss Zwisler spin_unlock(ptl); 1344f4200391SDave Jiang trace_dax_pmd_load_hole(inode, vmf, zero_page, ret); 1345642261acSRoss Zwisler return VM_FAULT_NOPAGE; 1346653b2ea3SRoss Zwisler 1347653b2ea3SRoss Zwisler fallback: 1348f4200391SDave Jiang trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, ret); 1349642261acSRoss Zwisler return VM_FAULT_FALLBACK; 1350642261acSRoss Zwisler } 1351642261acSRoss Zwisler 13529a0dd422SJan Kara static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, 1353a2d58167SDave Jiang const struct iomap_ops *ops) 1354642261acSRoss Zwisler { 1355f4200391SDave Jiang struct vm_area_struct *vma = vmf->vma; 1356642261acSRoss Zwisler struct address_space *mapping = vma->vm_file->f_mapping; 1357d8a849e1SDave Jiang unsigned long pmd_addr = vmf->address & PMD_MASK; 1358d8a849e1SDave Jiang bool write = vmf->flags & FAULT_FLAG_WRITE; 1359caa51d26SJan Kara bool sync; 13609484ab1bSJan Kara unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; 1361642261acSRoss Zwisler struct inode *inode = mapping->host; 1362642261acSRoss Zwisler int result = VM_FAULT_FALLBACK; 1363642261acSRoss Zwisler struct iomap iomap = { 0 }; 1364642261acSRoss Zwisler pgoff_t max_pgoff, pgoff; 1365642261acSRoss Zwisler void *entry; 1366642261acSRoss Zwisler loff_t pos; 1367642261acSRoss Zwisler int error; 1368302a5e31SJan Kara pfn_t pfn; 1369642261acSRoss Zwisler 1370282a8e03SRoss Zwisler /* 1371282a8e03SRoss Zwisler * Check whether offset isn't beyond end of file now. Caller is 1372282a8e03SRoss Zwisler * supposed to hold locks serializing us with truncate / punch hole so 1373282a8e03SRoss Zwisler * this is a reliable test. 1374282a8e03SRoss Zwisler */ 1375282a8e03SRoss Zwisler pgoff = linear_page_index(vma, pmd_addr); 1376957ac8c4SJeff Moyer max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); 1377282a8e03SRoss Zwisler 1378f4200391SDave Jiang trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); 1379282a8e03SRoss Zwisler 1380fffa281bSRoss Zwisler /* 1381fffa281bSRoss Zwisler * Make sure that the faulting address's PMD offset (color) matches 1382fffa281bSRoss Zwisler * the PMD offset from the start of the file. This is necessary so 1383fffa281bSRoss Zwisler * that a PMD range in the page table overlaps exactly with a PMD 1384fffa281bSRoss Zwisler * range in the radix tree. 1385fffa281bSRoss Zwisler */ 1386fffa281bSRoss Zwisler if ((vmf->pgoff & PG_PMD_COLOUR) != 1387fffa281bSRoss Zwisler ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) 1388fffa281bSRoss Zwisler goto fallback; 1389fffa281bSRoss Zwisler 1390642261acSRoss Zwisler /* Fall back to PTEs if we're going to COW */ 1391642261acSRoss Zwisler if (write && !(vma->vm_flags & VM_SHARED)) 1392642261acSRoss Zwisler goto fallback; 1393642261acSRoss Zwisler 1394642261acSRoss Zwisler /* If the PMD would extend outside the VMA */ 1395642261acSRoss Zwisler if (pmd_addr < vma->vm_start) 1396642261acSRoss Zwisler goto fallback; 1397642261acSRoss Zwisler if ((pmd_addr + PMD_SIZE) > vma->vm_end) 1398642261acSRoss Zwisler goto fallback; 1399642261acSRoss Zwisler 1400957ac8c4SJeff Moyer if (pgoff >= max_pgoff) { 1401282a8e03SRoss Zwisler result = VM_FAULT_SIGBUS; 1402282a8e03SRoss Zwisler goto out; 1403282a8e03SRoss Zwisler } 1404642261acSRoss Zwisler 1405642261acSRoss Zwisler /* If the PMD would extend beyond the file size */ 1406957ac8c4SJeff Moyer if ((pgoff | PG_PMD_COLOUR) >= max_pgoff) 1407642261acSRoss Zwisler goto fallback; 1408642261acSRoss Zwisler 1409642261acSRoss Zwisler /* 141091d25ba8SRoss Zwisler * grab_mapping_entry() will make sure we get a 2MiB empty entry, a 141191d25ba8SRoss Zwisler * 2MiB zero page entry or a DAX PMD. If it can't (because a 4k page 141291d25ba8SRoss Zwisler * is already in the tree, for instance), it will return -EEXIST and 141391d25ba8SRoss Zwisler * we just fall back to 4k entries. 14149f141d6eSJan Kara */ 14159f141d6eSJan Kara entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); 14169f141d6eSJan Kara if (IS_ERR(entry)) 1417876f2946SRoss Zwisler goto fallback; 1418876f2946SRoss Zwisler 1419876f2946SRoss Zwisler /* 1420e2093926SRoss Zwisler * It is possible, particularly with mixed reads & writes to private 1421e2093926SRoss Zwisler * mappings, that we have raced with a PTE fault that overlaps with 1422e2093926SRoss Zwisler * the PMD we need to set up. If so just return and the fault will be 1423e2093926SRoss Zwisler * retried. 1424e2093926SRoss Zwisler */ 1425e2093926SRoss Zwisler if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && 1426e2093926SRoss Zwisler !pmd_devmap(*vmf->pmd)) { 1427e2093926SRoss Zwisler result = 0; 1428e2093926SRoss Zwisler goto unlock_entry; 1429e2093926SRoss Zwisler } 1430e2093926SRoss Zwisler 1431e2093926SRoss Zwisler /* 1432876f2946SRoss Zwisler * Note that we don't use iomap_apply here. We aren't doing I/O, only 1433876f2946SRoss Zwisler * setting up a mapping, so really we're using iomap_begin() as a way 1434876f2946SRoss Zwisler * to look up our filesystem block. 1435876f2946SRoss Zwisler */ 1436876f2946SRoss Zwisler pos = (loff_t)pgoff << PAGE_SHIFT; 1437876f2946SRoss Zwisler error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); 1438876f2946SRoss Zwisler if (error) 1439876f2946SRoss Zwisler goto unlock_entry; 1440876f2946SRoss Zwisler 1441876f2946SRoss Zwisler if (iomap.offset + iomap.length < pos + PMD_SIZE) 14429f141d6eSJan Kara goto finish_iomap; 14439f141d6eSJan Kara 1444aaa422c4SDan Williams sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); 1445caa51d26SJan Kara 1446642261acSRoss Zwisler switch (iomap.type) { 1447642261acSRoss Zwisler case IOMAP_MAPPED: 1448302a5e31SJan Kara error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn); 1449302a5e31SJan Kara if (error < 0) 1450302a5e31SJan Kara goto finish_iomap; 1451302a5e31SJan Kara 14523fe0791cSDan Williams entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn, 1453caa51d26SJan Kara RADIX_DAX_PMD, write && !sync); 1454302a5e31SJan Kara if (IS_ERR(entry)) 1455302a5e31SJan Kara goto finish_iomap; 1456302a5e31SJan Kara 1457caa51d26SJan Kara /* 1458caa51d26SJan Kara * If we are doing synchronous page fault and inode needs fsync, 1459caa51d26SJan Kara * we can insert PMD into page tables only after that happens. 1460caa51d26SJan Kara * Skip insertion for now and return the pfn so that caller can 1461caa51d26SJan Kara * insert it after fsync is done. 1462caa51d26SJan Kara */ 1463caa51d26SJan Kara if (sync) { 1464caa51d26SJan Kara if (WARN_ON_ONCE(!pfnp)) 1465caa51d26SJan Kara goto finish_iomap; 1466caa51d26SJan Kara *pfnp = pfn; 1467caa51d26SJan Kara result = VM_FAULT_NEEDDSYNC; 1468caa51d26SJan Kara goto finish_iomap; 1469caa51d26SJan Kara } 1470caa51d26SJan Kara 1471302a5e31SJan Kara trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); 1472302a5e31SJan Kara result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, 1473302a5e31SJan Kara write); 1474642261acSRoss Zwisler break; 1475642261acSRoss Zwisler case IOMAP_UNWRITTEN: 1476642261acSRoss Zwisler case IOMAP_HOLE: 1477642261acSRoss Zwisler if (WARN_ON_ONCE(write)) 1478876f2946SRoss Zwisler break; 147991d25ba8SRoss Zwisler result = dax_pmd_load_hole(vmf, &iomap, entry); 1480642261acSRoss Zwisler break; 1481642261acSRoss Zwisler default: 1482642261acSRoss Zwisler WARN_ON_ONCE(1); 1483642261acSRoss Zwisler break; 1484642261acSRoss Zwisler } 1485642261acSRoss Zwisler 14869f141d6eSJan Kara finish_iomap: 14879f141d6eSJan Kara if (ops->iomap_end) { 14889f141d6eSJan Kara int copied = PMD_SIZE; 14899f141d6eSJan Kara 14909f141d6eSJan Kara if (result == VM_FAULT_FALLBACK) 14919f141d6eSJan Kara copied = 0; 14929f141d6eSJan Kara /* 14939f141d6eSJan Kara * The fault is done by now and there's no way back (other 14949f141d6eSJan Kara * thread may be already happily using PMD we have installed). 14959f141d6eSJan Kara * Just ignore error from ->iomap_end since we cannot do much 14969f141d6eSJan Kara * with it. 14979f141d6eSJan Kara */ 14989f141d6eSJan Kara ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, 14999f141d6eSJan Kara &iomap); 15009f141d6eSJan Kara } 1501876f2946SRoss Zwisler unlock_entry: 150291d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, pgoff); 1503642261acSRoss Zwisler fallback: 1504642261acSRoss Zwisler if (result == VM_FAULT_FALLBACK) { 1505d8a849e1SDave Jiang split_huge_pmd(vma, vmf->pmd, vmf->address); 1506642261acSRoss Zwisler count_vm_event(THP_FAULT_FALLBACK); 1507642261acSRoss Zwisler } 1508282a8e03SRoss Zwisler out: 1509f4200391SDave Jiang trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); 1510642261acSRoss Zwisler return result; 1511642261acSRoss Zwisler } 1512a2d58167SDave Jiang #else 15139a0dd422SJan Kara static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, 151401cddfe9SArnd Bergmann const struct iomap_ops *ops) 1515a2d58167SDave Jiang { 1516a2d58167SDave Jiang return VM_FAULT_FALLBACK; 1517a2d58167SDave Jiang } 1518642261acSRoss Zwisler #endif /* CONFIG_FS_DAX_PMD */ 1519a2d58167SDave Jiang 1520a2d58167SDave Jiang /** 1521a2d58167SDave Jiang * dax_iomap_fault - handle a page fault on a DAX file 1522a2d58167SDave Jiang * @vmf: The description of the fault 1523cec04e8cSJan Kara * @pe_size: Size of the page to fault in 15249a0dd422SJan Kara * @pfnp: PFN to insert for synchronous faults if fsync is required 1525c0b24625SJan Kara * @iomap_errp: Storage for detailed error code in case of error 1526cec04e8cSJan Kara * @ops: Iomap ops passed from the file system 1527a2d58167SDave Jiang * 1528a2d58167SDave Jiang * When a page fault occurs, filesystems may call this helper in 1529a2d58167SDave Jiang * their fault handler for DAX files. dax_iomap_fault() assumes the caller 1530a2d58167SDave Jiang * has done all the necessary locking for page fault to proceed 1531a2d58167SDave Jiang * successfully. 1532a2d58167SDave Jiang */ 1533c791ace1SDave Jiang int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 1534c0b24625SJan Kara pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) 1535a2d58167SDave Jiang { 1536c791ace1SDave Jiang switch (pe_size) { 1537c791ace1SDave Jiang case PE_SIZE_PTE: 1538c0b24625SJan Kara return dax_iomap_pte_fault(vmf, pfnp, iomap_errp, ops); 1539c791ace1SDave Jiang case PE_SIZE_PMD: 15409a0dd422SJan Kara return dax_iomap_pmd_fault(vmf, pfnp, ops); 1541a2d58167SDave Jiang default: 1542a2d58167SDave Jiang return VM_FAULT_FALLBACK; 1543a2d58167SDave Jiang } 1544a2d58167SDave Jiang } 1545a2d58167SDave Jiang EXPORT_SYMBOL_GPL(dax_iomap_fault); 154671eab6dfSJan Kara 154771eab6dfSJan Kara /** 154871eab6dfSJan Kara * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables 154971eab6dfSJan Kara * @vmf: The description of the fault 155071eab6dfSJan Kara * @pe_size: Size of entry to be inserted 155171eab6dfSJan Kara * @pfn: PFN to insert 155271eab6dfSJan Kara * 155371eab6dfSJan Kara * This function inserts writeable PTE or PMD entry into page tables for mmaped 155471eab6dfSJan Kara * DAX file. It takes care of marking corresponding radix tree entry as dirty 155571eab6dfSJan Kara * as well. 155671eab6dfSJan Kara */ 155771eab6dfSJan Kara static int dax_insert_pfn_mkwrite(struct vm_fault *vmf, 155871eab6dfSJan Kara enum page_entry_size pe_size, 155971eab6dfSJan Kara pfn_t pfn) 156071eab6dfSJan Kara { 156171eab6dfSJan Kara struct address_space *mapping = vmf->vma->vm_file->f_mapping; 156271eab6dfSJan Kara void *entry, **slot; 156371eab6dfSJan Kara pgoff_t index = vmf->pgoff; 156471eab6dfSJan Kara int vmf_ret, error; 156571eab6dfSJan Kara 1566b93b0163SMatthew Wilcox xa_lock_irq(&mapping->i_pages); 156771eab6dfSJan Kara entry = get_unlocked_mapping_entry(mapping, index, &slot); 156871eab6dfSJan Kara /* Did we race with someone splitting entry or so? */ 156971eab6dfSJan Kara if (!entry || 157071eab6dfSJan Kara (pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) || 157171eab6dfSJan Kara (pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) { 157271eab6dfSJan Kara put_unlocked_mapping_entry(mapping, index, entry); 1573b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 157471eab6dfSJan Kara trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, 157571eab6dfSJan Kara VM_FAULT_NOPAGE); 157671eab6dfSJan Kara return VM_FAULT_NOPAGE; 157771eab6dfSJan Kara } 1578b93b0163SMatthew Wilcox radix_tree_tag_set(&mapping->i_pages, index, PAGECACHE_TAG_DIRTY); 157971eab6dfSJan Kara entry = lock_slot(mapping, slot); 1580b93b0163SMatthew Wilcox xa_unlock_irq(&mapping->i_pages); 158171eab6dfSJan Kara switch (pe_size) { 158271eab6dfSJan Kara case PE_SIZE_PTE: 158371eab6dfSJan Kara error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); 158471eab6dfSJan Kara vmf_ret = dax_fault_return(error); 158571eab6dfSJan Kara break; 158671eab6dfSJan Kara #ifdef CONFIG_FS_DAX_PMD 158771eab6dfSJan Kara case PE_SIZE_PMD: 158871eab6dfSJan Kara vmf_ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, 158971eab6dfSJan Kara pfn, true); 159071eab6dfSJan Kara break; 159171eab6dfSJan Kara #endif 159271eab6dfSJan Kara default: 159371eab6dfSJan Kara vmf_ret = VM_FAULT_FALLBACK; 159471eab6dfSJan Kara } 159571eab6dfSJan Kara put_locked_mapping_entry(mapping, index); 159671eab6dfSJan Kara trace_dax_insert_pfn_mkwrite(mapping->host, vmf, vmf_ret); 159771eab6dfSJan Kara return vmf_ret; 159871eab6dfSJan Kara } 159971eab6dfSJan Kara 160071eab6dfSJan Kara /** 160171eab6dfSJan Kara * dax_finish_sync_fault - finish synchronous page fault 160271eab6dfSJan Kara * @vmf: The description of the fault 160371eab6dfSJan Kara * @pe_size: Size of entry to be inserted 160471eab6dfSJan Kara * @pfn: PFN to insert 160571eab6dfSJan Kara * 160671eab6dfSJan Kara * This function ensures that the file range touched by the page fault is 160771eab6dfSJan Kara * stored persistently on the media and handles inserting of appropriate page 160871eab6dfSJan Kara * table entry. 160971eab6dfSJan Kara */ 161071eab6dfSJan Kara int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 161171eab6dfSJan Kara pfn_t pfn) 161271eab6dfSJan Kara { 161371eab6dfSJan Kara int err; 161471eab6dfSJan Kara loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; 161571eab6dfSJan Kara size_t len = 0; 161671eab6dfSJan Kara 161771eab6dfSJan Kara if (pe_size == PE_SIZE_PTE) 161871eab6dfSJan Kara len = PAGE_SIZE; 161971eab6dfSJan Kara else if (pe_size == PE_SIZE_PMD) 162071eab6dfSJan Kara len = PMD_SIZE; 162171eab6dfSJan Kara else 162271eab6dfSJan Kara WARN_ON_ONCE(1); 162371eab6dfSJan Kara err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); 162471eab6dfSJan Kara if (err) 162571eab6dfSJan Kara return VM_FAULT_SIGBUS; 162671eab6dfSJan Kara return dax_insert_pfn_mkwrite(vmf, pe_size, pfn); 162771eab6dfSJan Kara } 162871eab6dfSJan Kara EXPORT_SYMBOL_GPL(dax_finish_sync_fault); 1629