diff options
-rw-r--r-- | fs/Kconfig | 1 | ||||
-rw-r--r-- | fs/dax.c | 828 | ||||
-rw-r--r-- | fs/ext2/file.c | 35 | ||||
-rw-r--r-- | fs/ext4/inode.c | 3 | ||||
-rw-r--r-- | fs/iomap.c | 5 | ||||
-rw-r--r-- | fs/xfs/xfs_aops.c | 26 | ||||
-rw-r--r-- | fs/xfs/xfs_aops.h | 3 | ||||
-rw-r--r-- | fs/xfs/xfs_file.c | 10 | ||||
-rw-r--r-- | include/linux/dax.h | 58 | ||||
-rw-r--r-- | include/linux/iomap.h | 1 | ||||
-rw-r--r-- | mm/filemap.c | 5 |
11 files changed, 542 insertions, 433 deletions
diff --git a/fs/Kconfig b/fs/Kconfig index 4bd03a2b0518..8e9e5f4104f4 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -55,7 +55,6 @@ config FS_DAX_PMD depends on FS_DAX depends on ZONE_DEVICE depends on TRANSPARENT_HUGEPAGE - depends on BROKEN endif # BLOCK @@ -34,25 +34,11 @@ #include <linux/iomap.h> #include "internal.h" -/* - * We use lowest available bit in exceptional entry for locking, other two - * bits to determine entry type. In total 3 special bits. - */ -#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 3) -#define RADIX_DAX_PTE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) -#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) -#define RADIX_DAX_TYPE_MASK (RADIX_DAX_PTE | RADIX_DAX_PMD) -#define RADIX_DAX_TYPE(entry) ((unsigned long)entry & RADIX_DAX_TYPE_MASK) -#define RADIX_DAX_SECTOR(entry) (((unsigned long)entry >> RADIX_DAX_SHIFT)) -#define RADIX_DAX_ENTRY(sector, pmd) ((void *)((unsigned long)sector << \ - RADIX_DAX_SHIFT | (pmd ? RADIX_DAX_PMD : RADIX_DAX_PTE) | \ - RADIX_TREE_EXCEPTIONAL_ENTRY)) - /* We choose 4096 entries - same as per-zone page wait tables */ #define DAX_WAIT_TABLE_BITS 12 #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) -wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; +static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; static int __init init_dax_wait_table(void) { @@ -64,14 +50,6 @@ static int __init init_dax_wait_table(void) } fs_initcall(init_dax_wait_table); -static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, - pgoff_t index) -{ - unsigned long hash = hash_long((unsigned long)mapping ^ index, - DAX_WAIT_TABLE_BITS); - return wait_table + hash; -} - static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax) { struct request_queue *q = bdev->bd_queue; @@ -98,6 +76,26 @@ static void dax_unmap_atomic(struct block_device *bdev, blk_queue_exit(bdev->bd_queue); } +static int dax_is_pmd_entry(void *entry) +{ + return (unsigned long)entry & RADIX_DAX_PMD; +} + +static int dax_is_pte_entry(void *entry) +{ + return !((unsigned long)entry & RADIX_DAX_PMD); +} + +static int dax_is_zero_entry(void *entry) +{ + return (unsigned long)entry & RADIX_DAX_HZP; +} + +static int dax_is_empty_entry(void *entry) +{ + return (unsigned long)entry & RADIX_DAX_EMPTY; +} + struct page *read_dax_sector(struct block_device *bdev, sector_t n) { struct page *page = alloc_pages(GFP_KERNEL, 0); @@ -123,19 +121,6 @@ static bool buffer_written(struct buffer_head *bh) return buffer_mapped(bh) && !buffer_unwritten(bh); } -/* - * When ext4 encounters a hole, it returns without modifying the buffer_head - * which means that we can't trust b_size. To cope with this, we set b_state - * to 0 before calling get_block and, if any bit is set, we know we can trust - * b_size. Unfortunate, really, since ext4 knows precisely how long a hole is - * and would save us time calling get_block repeatedly. - */ -static bool buffer_size_valid(struct buffer_head *bh) -{ - return bh->b_state != 0; -} - - static sector_t to_sector(const struct buffer_head *bh, const struct inode *inode) { @@ -177,8 +162,6 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter, rc = get_block(inode, block, bh, rw == WRITE); if (rc) break; - if (!buffer_size_valid(bh)) - bh->b_size = 1 << blkbits; bh_max = pos - first + bh->b_size; bdev = bh->b_bdev; /* @@ -300,7 +283,7 @@ EXPORT_SYMBOL_GPL(dax_do_io); */ struct exceptional_entry_key { struct address_space *mapping; - unsigned long index; + pgoff_t entry_start; }; struct wait_exceptional_entry_queue { @@ -308,6 +291,26 @@ struct wait_exceptional_entry_queue { struct exceptional_entry_key key; }; +static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, + pgoff_t index, void *entry, struct exceptional_entry_key *key) +{ + unsigned long hash; + + /* + * If 'entry' is a PMD, align the 'index' that we use for the wait + * queue to the start of that PMD. This ensures that all offsets in + * the range covered by the PMD map to the same bit lock. + */ + if (dax_is_pmd_entry(entry)) + index &= ~((1UL << (PMD_SHIFT - PAGE_SHIFT)) - 1); + + key->mapping = mapping; + key->entry_start = index; + + hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); + return wait_table + hash; +} + static int wake_exceptional_entry_func(wait_queue_t *wait, unsigned int mode, int sync, void *keyp) { @@ -316,7 +319,7 @@ static int wake_exceptional_entry_func(wait_queue_t *wait, unsigned int mode, container_of(wait, struct wait_exceptional_entry_queue, wait); if (key->mapping != ewait->key.mapping || - key->index != ewait->key.index) + key->entry_start != ewait->key.entry_start) return 0; return autoremove_wake_function(wait, mode, sync, NULL); } @@ -372,24 +375,24 @@ static inline void *unlock_slot(struct address_space *mapping, void **slot) static void *get_unlocked_mapping_entry(struct address_space *mapping, pgoff_t index, void ***slotp) { - void *ret, **slot; + void *entry, **slot; struct wait_exceptional_entry_queue ewait; - wait_queue_head_t *wq = dax_entry_waitqueue(mapping, index); + wait_queue_head_t *wq; init_wait(&ewait.wait); ewait.wait.func = wake_exceptional_entry_func; - ewait.key.mapping = mapping; - ewait.key.index = index; for (;;) { - ret = __radix_tree_lookup(&mapping->page_tree, index, NULL, + entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot); - if (!ret || !radix_tree_exceptional_entry(ret) || + if (!entry || !radix_tree_exceptional_entry(entry) || !slot_locked(mapping, slot)) { if (slotp) *slotp = slot; - return ret; + return entry; } + + wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); prepare_to_wait_exclusive(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); spin_unlock_irq(&mapping->tree_lock); @@ -399,52 +402,157 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping, } } +static void put_locked_mapping_entry(struct address_space *mapping, + pgoff_t index, void *entry) +{ + if (!radix_tree_exceptional_entry(entry)) { + unlock_page(entry); + put_page(entry); + } else { + dax_unlock_mapping_entry(mapping, index); + } +} + +/* + * Called when we are done with radix tree entry we looked up via + * get_unlocked_mapping_entry() and which we didn't lock in the end. + */ +static void put_unlocked_mapping_entry(struct address_space *mapping, + pgoff_t index, void *entry) +{ + if (!radix_tree_exceptional_entry(entry)) + return; + + /* We have to wake up next waiter for the radix tree entry lock */ + dax_wake_mapping_entry_waiter(mapping, index, entry, false); +} + /* * Find radix tree entry at given index. If it points to a page, return with * the page locked. If it points to the exceptional entry, return with the * radix tree entry locked. If the radix tree doesn't contain given index, * create empty exceptional entry for the index and return with it locked. * + * When requesting an entry with size RADIX_DAX_PMD, grab_mapping_entry() will + * either return that locked entry or will return an error. This error will + * happen if there are any 4k entries (either zero pages or DAX entries) + * within the 2MiB range that we are requesting. + * + * We always favor 4k entries over 2MiB entries. There isn't a flow where we + * evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB + * insertion will fail if it finds any 4k entries already in the tree, and a + * 4k insertion will cause an existing 2MiB entry to be unmapped and + * downgraded to 4k entries. This happens for both 2MiB huge zero pages as + * well as 2MiB empty entries. + * + * The exception to this downgrade path is for 2MiB DAX PMD entries that have + * real storage backing them. We will leave these real 2MiB DAX entries in + * the tree, and PTE writes will simply dirty the entire 2MiB DAX entry. + * * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For * persistent memory the benefit is doubtful. We can add that later if we can * show it helps. */ -static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index) +static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, + unsigned long size_flag) { - void *ret, **slot; + bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */ + void *entry, **slot; restart: spin_lock_irq(&mapping->tree_lock); - ret = get_unlocked_mapping_entry(mapping, index, &slot); + entry = get_unlocked_mapping_entry(mapping, index, &slot); + + if (entry) { + if (size_flag & RADIX_DAX_PMD) { + if (!radix_tree_exceptional_entry(entry) || + dax_is_pte_entry(entry)) { + put_unlocked_mapping_entry(mapping, index, + entry); + entry = ERR_PTR(-EEXIST); + goto out_unlock; + } + } else { /* trying to grab a PTE entry */ + if (radix_tree_exceptional_entry(entry) && + dax_is_pmd_entry(entry) && + (dax_is_zero_entry(entry) || + dax_is_empty_entry(entry))) { + pmd_downgrade = true; + } + } + } + /* No entry for given index? Make sure radix tree is big enough. */ - if (!ret) { + if (!entry || pmd_downgrade) { int err; + if (pmd_downgrade) { + /* + * Make sure 'entry' remains valid while we drop + * mapping->tree_lock. + */ + entry = lock_slot(mapping, slot); + } + spin_unlock_irq(&mapping->tree_lock); err = radix_tree_preload( mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); - if (err) + if (err) { + if (pmd_downgrade) + put_locked_mapping_entry(mapping, index, entry); return ERR_PTR(err); - ret = (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | - RADIX_DAX_ENTRY_LOCK); + } + + /* + * Besides huge zero pages the only other thing that gets + * downgraded are empty entries which don't need to be + * unmapped. + */ + if (pmd_downgrade && dax_is_zero_entry(entry)) + unmap_mapping_range(mapping, + (index << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0); + spin_lock_irq(&mapping->tree_lock); - err = radix_tree_insert(&mapping->page_tree, index, ret); + + if (pmd_downgrade) { + radix_tree_delete(&mapping->page_tree, index); + mapping->nrexceptional--; + dax_wake_mapping_entry_waiter(mapping, index, entry, + true); + } + + entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY); + + err = __radix_tree_insert(&mapping->page_tree, index, + dax_radix_order(entry), entry); radix_tree_preload_end(); if (err) { spin_unlock_irq(&mapping->tree_lock); - /* Someone already created the entry? */ - if (err == -EEXIST) + /* + * Someone already created the entry? This is a + * normal failure when inserting PMDs in a range + * that already contains PTEs. In that case we want + * to return -EEXIST immediately. + */ + if (err == -EEXIST && !(size_flag & RADIX_DAX_PMD)) goto restart; + /* + * Our insertion of a DAX PMD entry failed, most + * likely because it collided with a PTE sized entry + * at a different index in the PMD range. We haven't + * inserted anything into the radix tree and have no + * waiters to wake. + */ return ERR_PTR(err); } /* Good, we have inserted empty locked entry into the tree. */ mapping->nrexceptional++; spin_unlock_irq(&mapping->tree_lock); - return ret; + return entry; } /* Normal page in radix tree? */ - if (!radix_tree_exceptional_entry(ret)) { - struct page *page = ret; + if (!radix_tree_exceptional_entry(entry)) { + struct page *page = entry; get_page(page); spin_unlock_irq(&mapping->tree_lock); @@ -457,15 +565,26 @@ restart: } return page; } - ret = lock_slot(mapping, slot); + entry = lock_slot(mapping, slot); + out_unlock: spin_unlock_irq(&mapping->tree_lock); - return ret; + return entry; } +/* + * We do not necessarily hold the mapping->tree_lock when we call this + * function so it is possible that 'entry' is no longer a valid item in the + * radix tree. This is okay because all we really need to do is to find the + * correct waitqueue where tasks might be waiting for that old 'entry' and + * wake them. + */ void dax_wake_mapping_entry_waiter(struct address_space *mapping, - pgoff_t index, bool wake_all) + pgoff_t index, void *entry, bool wake_all) { - wait_queue_head_t *wq = dax_entry_waitqueue(mapping, index); + struct exceptional_entry_key key; + wait_queue_head_t *wq; + + wq = dax_entry_waitqueue(mapping, index, entry, &key); /* * Checking for locked entry and prepare_to_wait_exclusive() happens @@ -473,54 +592,24 @@ void dax_wake_mapping_entry_waiter(struct address_space *mapping, * So at this point all tasks that could have seen our entry locked * must be in the waitqueue and the following check will see them. */ - if (waitqueue_active(wq)) { - struct exceptional_entry_key key; - - key.mapping = mapping; - key.index = index; + if (waitqueue_active(wq)) __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); - } } void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index) { - void *ret, **slot; + void *entry, **slot; spin_lock_irq(&mapping->tree_lock); - ret = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot); - if (WARN_ON_ONCE(!ret || !radix_tree_exceptional_entry(ret) || + entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot); + if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) || !slot_locked(mapping, slot))) { spin_unlock_irq(&mapping->tree_lock); return; } unlock_slot(mapping, slot); spin_unlock_irq(&mapping->tree_lock); - dax_wake_mapping_entry_waiter(mapping, index, false); -} - -static void put_locked_mapping_entry(struct address_space *mapping, - pgoff_t index, void *entry) -{ - if (!radix_tree_exceptional_entry(entry)) { - unlock_page(entry); - put_page(entry); - } else { - dax_unlock_mapping_entry(mapping, index); - } -} - -/* - * Called when we are done with radix tree entry we looked up via - * get_unlocked_mapping_entry() and which we didn't lock in the end. - */ -static void put_unlocked_mapping_entry(struct address_space *mapping, - pgoff_t index, void *entry) -{ - if (!radix_tree_exceptional_entry(entry)) - return; - - /* We have to wake up next waiter for the radix tree entry lock */ - dax_wake_mapping_entry_waiter(mapping, index, false); + dax_wake_mapping_entry_waiter(mapping, index, entry, false); } /* @@ -547,7 +636,7 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) radix_tree_delete(&mapping->page_tree, index); mapping->nrexceptional--; spin_unlock_irq(&mapping->tree_lock); - dax_wake_mapping_entry_waiter(mapping, index, true); + dax_wake_mapping_entry_waiter(mapping, index, entry, true); return 1; } @@ -600,11 +689,17 @@ static int copy_user_dax(struct block_device *bdev, sector_t sector, size_t size return 0; } -#define DAX_PMD_INDEX(page_index) (page_index & (PMD_MASK >> PAGE_SHIFT)) - +/* + * By this point grab_mapping_entry() has ensured that we have a locked entry + * of the appropriate size so we don't have to worry about downgrading PMDs to + * PTEs. If we happen to be trying to insert a PTE and there is a PMD + * already in the tree, we will skip the insertion and just dirty the PMD as + * appropriate. + */ static void *dax_insert_mapping_entry(struct address_space *mapping, struct vm_fault *vmf, - void *entry, sector_t sector) + void *entry, sector_t sector, + unsigned long flags) { struct radix_tree_root *page_tree = &mapping->page_tree; int error = 0; @@ -627,22 +722,35 @@ static void *dax_insert_mapping_entry(struct address_space *mapping, error = radix_tree_preload(vmf->gfp_mask & ~__GFP_HIGHMEM); if (error) return ERR_PTR(error); + } else if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_HZP)) { + /* replacing huge zero page with PMD block mapping */ + unmap_mapping_range(mapping, + (vmf->pgoff << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0); } spin_lock_irq(&mapping->tree_lock); - new_entry = (void *)((unsigned long)RADIX_DAX_ENTRY(sector, false) | - RADIX_DAX_ENTRY_LOCK); + new_entry = dax_radix_locked_entry(sector, flags); + if (hole_fill) { __delete_from_page_cache(entry, NULL); /* Drop pagecache reference */ put_page(entry); - error = radix_tree_insert(page_tree, index, new_entry); + error = __radix_tree_insert(page_tree, index, + dax_radix_order(new_entry), new_entry); if (error) { new_entry = ERR_PTR(error); goto unlock; } mapping->nrexceptional++; - } else { + } else if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { + /* + * Only swap our new entry into the radix tree if the current + * entry is a zero page or an empty entry. If a normal PTE or + * PMD entry is already in the tree, we leave it alone. This + * means that if we are trying to insert a PTE and the + * existing entry is a PMD, we will just leave the PMD in the + * tree and dirty it if necessary. + */ void **slot; void *ret; @@ -672,7 +780,6 @@ static int dax_writeback_one(struct block_device *bdev, struct address_space *mapping, pgoff_t index, void *entry) { struct radix_tree_root *page_tree = &mapping->page_tree; - int type = RADIX_DAX_TYPE(entry); struct radix_tree_node *node; struct blk_dax_ctl dax; void **slot; @@ -693,13 +800,21 @@ static int dax_writeback_one(struct block_device *bdev, if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) goto unlock; - if (WARN_ON_ONCE(type != RADIX_DAX_PTE && type != RADIX_DAX_PMD)) { + if (WARN_ON_ONCE(dax_is_empty_entry(entry) || + dax_is_zero_entry(entry))) { ret = -EIO; goto unlock; } - dax.sector = RADIX_DAX_SECTOR(entry); - dax.size = (type == RADIX_DAX_PMD ? PMD_SIZE : PAGE_SIZE); + /* + * Even if dax_writeback_mapping_range() was given a wbc->range_start + * in the middle of a PMD, the 'index' we are given will be aligned to + * the start index of the PMD, as will the sector we pull from + * 'entry'. This allows us to flush for PMD_SIZE and not have to + * worry about partial PMD writebacks. + */ + dax.sector = dax_radix_sector(entry); + dax.size = PAGE_SIZE << dax_radix_order(entry); spin_unlock_irq(&mapping->tree_lock); /* @@ -738,12 +853,11 @@ int dax_writeback_mapping_range(struct address_space *mapping, struct block_device *bdev, struct writeback_control *wbc) { struct inode *inode = mapping->host; - pgoff_t start_index, end_index, pmd_index; + pgoff_t start_index, end_index; pgoff_t indices[PAGEVEC_SIZE]; struct pagevec pvec; bool done = false; int i, ret = 0; - void *entry; if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) return -EIO; @@ -753,15 +867,6 @@ int dax_writeback_mapping_range(struct address_space *mapping, start_index = wbc->range_start >> PAGE_SHIFT; end_index = wbc->range_end >> PAGE_SHIFT; - pmd_index = DAX_PMD_INDEX(start_index); - - rcu_read_lock(); - entry = radix_tree_lookup(&mapping->page_tree, pmd_index); - rcu_read_unlock(); - - /* see if the start of our range is covered by a PMD entry */ - if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD) - start_index = pmd_index; tag_pages_for_writeback(mapping, start_index, end_index); @@ -806,7 +911,7 @@ static int dax_insert_mapping(struct address_space *mapping, return PTR_ERR(dax.addr); dax_unmap_atomic(bdev, &dax); - ret = dax_insert_mapping_entry(mapping, vmf, entry, dax.sector); + ret = dax_insert_mapping_entry(mapping, vmf, entry, dax.sector, 0); if (IS_ERR(ret)) return PTR_ERR(ret); *entryp = ret; @@ -853,7 +958,7 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, bh.b_bdev = inode->i_sb->s_bdev; bh.b_size = PAGE_SIZE; - entry = grab_mapping_entry(mapping, vmf->pgoff); + entry = grab_mapping_entry(mapping, vmf->pgoff, 0); if (IS_ERR(entry)) { error = PTR_ERR(entry); goto out; @@ -913,224 +1018,6 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } EXPORT_SYMBOL_GPL(dax_fault); -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) -/* - * The 'colour' (ie low bits) within a PMD of a page offset. This comes up - * more often than one might expect in the below function. - */ -#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) - -static void __dax_dbg(struct buffer_head *bh, unsigned long address, - const char *reason, const char *fn) -{ - if (bh) { - char bname[BDEVNAME_SIZE]; - bdevname(bh->b_bdev, bname); - pr_debug("%s: %s addr: %lx dev %s state %lx start %lld " - "length %zd fallback: %s\n", fn, current->comm, - address, bname, bh->b_state, (u64)bh->b_blocknr, - bh->b_size, reason); - } else { - pr_debug("%s: %s addr: %lx fallback: %s\n", fn, - current->comm, address, reason); - } -} - -#define dax_pmd_dbg(bh, address, reason) __dax_dbg(bh, address, reason, "dax_pmd") - -/** - * dax_pmd_fault - handle a PMD fault on a DAX file - * @vma: The virtual memory area where the fault occurred - * @vmf: The description of the fault - * @get_block: The filesystem method used to translate file offsets to blocks - * - * When a page fault occurs, filesystems may call this helper in their - * pmd_fault handler for DAX files. - */ -int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, - pmd_t *pmd, unsigned int flags, get_block_t get_block) -{ - struct file *file = vma->vm_file; - struct address_space *mapping = file->f_mapping; - struct inode *inode = mapping->host; - struct buffer_head bh; - unsigned blkbits = inode->i_blkbits; - unsigned long pmd_addr = address & PMD_MASK; - bool write = flags & FAULT_FLAG_WRITE; - struct block_device *bdev; - pgoff_t size, pgoff; - sector_t block; - int result = 0; - bool alloc = false; - - /* dax pmd mappings require pfn_t_devmap() */ - if (!IS_ENABLED(CONFIG_FS_DAX_PMD)) - return VM_FAULT_FALLBACK; - - /* Fall back to PTEs if we're going to COW */ - if (write && !(vma->vm_flags & VM_SHARED)) { - split_huge_pmd(vma, pmd, address); - dax_pmd_dbg(NULL, address, "cow write"); - return VM_FAULT_FALLBACK; - } - /* If the PMD would extend outside the VMA */ - if (pmd_addr < vma->vm_start) { - dax_pmd_dbg(NULL, address, "vma start unaligned"); - return VM_FAULT_FALLBACK; - } - if ((pmd_addr + PMD_SIZE) > vma->vm_end) { - dax_pmd_dbg(NULL, address, "vma end unaligned"); - return VM_FAULT_FALLBACK; - } - - pgoff = linear_page_index(vma, pmd_addr); - size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; - if (pgoff >= size) - return VM_FAULT_SIGBUS; - /* If the PMD would cover blocks out of the file */ - if ((pgoff | PG_PMD_COLOUR) >= size) { - dax_pmd_dbg(NULL, address, - "offset + huge page size > file size"); - return VM_FAULT_FALLBACK; - } - - memset(&bh, 0, sizeof(bh)); - bh.b_bdev = inode->i_sb->s_bdev; - block = (sector_t)pgoff << (PAGE_SHIFT - blkbits); - - bh.b_size = PMD_SIZE; - - if (get_block(inode, block, &bh, 0) != 0) - return VM_FAULT_SIGBUS; - - if (!buffer_mapped(&bh) && write) { - if (get_block(inode, block, &bh, 1) != 0) - return VM_FAULT_SIGBUS; - alloc = true; - WARN_ON_ONCE(buffer_unwritten(&bh) || buffer_new(&bh)); - } - - bdev = bh.b_bdev; - - /* - * If the filesystem isn't willing to tell us the length of a hole, - * just fall back to PTEs. Calling get_block 512 times in a loop - * would be silly. - */ - if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) { - dax_pmd_dbg(&bh, address, "allocated block too small"); - return VM_FAULT_FALLBACK; - } - - /* - * If we allocated new storage, make sure no process has any - * zero pages covering this hole - */ - if (alloc) { - loff_t lstart = pgoff << PAGE_SHIFT; - loff_t lend = lstart + PMD_SIZE - 1; /* inclusive */ - - truncate_pagecache_range(inode, lstart, lend); - } - - if (!write && !buffer_mapped(&bh)) { - spinlock_t *ptl; - pmd_t entry; - struct page *zero_page = mm_get_huge_zero_page(vma->vm_mm); - - if (unlikely(!zero_page)) { - dax_pmd_dbg(&bh, address, "no zero page"); - goto fallback; - } - - ptl = pmd_lock(vma->vm_mm, pmd); - if (!pmd_none(*pmd)) { - spin_unlock(ptl); - dax_pmd_dbg(&bh, address, "pmd already present"); - goto fallback; - } - - dev_dbg(part_to_dev(bdev->bd_part), - "%s: %s addr: %lx pfn: <zero> sect: %llx\n", - __func__, current->comm, address, - (unsigned long long) to_sector(&bh, inode)); - - entry = mk_pmd(zero_page, vma->vm_page_prot); - entry = pmd_mkhuge(entry); - set_pmd_at(vma->vm_mm, pmd_addr, pmd, entry); - result = VM_FAULT_NOPAGE; - spin_unlock(ptl); - } else { - struct blk_dax_ctl dax = { - .sector = to_sector(&bh, inode), - .size = PMD_SIZE, - }; - long length = dax_map_atomic(bdev, &dax); - - if (length < 0) { - dax_pmd_dbg(&bh, address, "dax-error fallback"); - goto fallback; - } - if (length < PMD_SIZE) { - dax_pmd_dbg(&bh, address, "dax-length too small"); - dax_unmap_atomic(bdev, &dax); - goto fallback; - } - if (pfn_t_to_pfn(dax.pfn) & PG_PMD_COLOUR) { - dax_pmd_dbg(&bh, address, "pfn unaligned"); - dax_unmap_atomic(bdev, &dax); - goto fallback; - } - - if (!pfn_t_devmap(dax.pfn)) { - dax_unmap_atomic(bdev, &dax); - dax_pmd_dbg(&bh, address, "pfn not in memmap"); - goto fallback; - } - dax_unmap_atomic(bdev, &dax); - - /* - * For PTE faults we insert a radix tree entry for reads, and - * leave it clean. Then on the first write we dirty the radix - * tree entry via the dax_pfn_mkwrite() path. This sequence - * allows the dax_pfn_mkwrite() call to be simpler and avoid a - * call into get_block() to translate the pgoff to a sector in - * order to be able to create a new radix tree entry. - * - * The PMD path doesn't have an equivalent to - * dax_pfn_mkwrite(), though, so for a read followed by a - * write we traverse all the way through dax_pmd_fault() - * twice. This means we can just skip inserting a radix tree - * entry completely on the initial read and just wait until - * the write to insert a dirty entry. - */ - if (write) { - /* - * We should insert radix-tree entry and dirty it here. - * For now this is broken... - */ - } - - dev_dbg(part_to_dev(bdev->bd_part), - "%s: %s addr: %lx pfn: %lx sect: %llx\n", - __func__, current->comm, address, - pfn_t_to_pfn(dax.pfn), - (unsigned long long) dax.sector); - result |= vmf_insert_pfn_pmd(vma, address, pmd, - dax.pfn, write); - } - - out: - return result; - - fallback: - count_vm_event(THP_FAULT_FALLBACK); - result = VM_FAULT_FALLBACK; - goto out; -} -EXPORT_SYMBOL_GPL(dax_pmd_fault); -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ - /** * dax_pfn_mkwrite - handle first write to DAX page * @vma: The virtual memory area where the fault occurred @@ -1214,7 +1101,8 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length, /* Block boundary? Nothing to do */ if (!length) return 0; - BUG_ON((offset + length) > PAGE_SIZE); + if (WARN_ON_ONCE((offset + length) > PAGE_SIZE)) + return -EINVAL; memset(&bh, 0, sizeof(bh)); bh.b_bdev = inode->i_sb->s_bdev; @@ -1245,8 +1133,13 @@ int dax_truncate_page(struct inode *inode, loff_t from, get_block_t get_block) EXPORT_SYMBOL_GPL(dax_truncate_page); #ifdef CONFIG_FS_IOMAP +static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) +{ + return iomap->blkno + (((pos & PAGE_MASK) - iomap->offset) >> 9); +} + static loff_t -iomap_dax_actor(struct inode *inode, loff_t pos, loff_t length, void *data, +dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct iov_iter *iter = data; @@ -1270,8 +1163,7 @@ iomap_dax_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct blk_dax_ctl dax = { 0 }; ssize_t map_len; - dax.sector = iomap->blkno + - (((pos & PAGE_MASK) - iomap->offset) >> 9); + dax.sector = dax_iomap_sector(iomap, pos); dax.size = (length + offset + PAGE_SIZE - 1) & PAGE_MASK; map_len = dax_map_atomic(iomap->bdev, &dax); if (map_len < 0) { @@ -1303,7 +1195,7 @@ iomap_dax_actor(struct inode *inode, loff_t pos, loff_t length, void *data, } /** - * iomap_dax_rw - Perform I/O to a DAX file + * dax_iomap_rw - Perform I/O to a DAX file * @iocb: The control block for this I/O * @iter: The addresses to do I/O from or to * @ops: iomap ops passed from the file system @@ -1313,7 +1205,7 @@ iomap_dax_actor(struct inode *inode, loff_t pos, loff_t length, void *data, * and evicting any page cache pages in the region under I/O. */ ssize_t -iomap_dax_rw(struct kiocb *iocb, struct iov_iter *iter, +dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, struct iomap_ops *ops) { struct address_space *mapping = iocb->ki_filp->f_mapping; @@ -1343,7 +1235,7 @@ iomap_dax_rw(struct kiocb *iocb, struct iov_iter *iter, while (iov_iter_count(iter)) { ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, - iter, iomap_dax_actor); + iter, dax_iomap_actor); if (ret <= 0) break; pos += ret; @@ -1353,10 +1245,10 @@ iomap_dax_rw(struct kiocb *iocb, struct iov_iter *iter, iocb->ki_pos += done; return done ? done : ret; } -EXPORT_SYMBOL_GPL(iomap_dax_rw); +EXPORT_SYMBOL_GPL(dax_iomap_rw); /** - * iomap_dax_fault - handle a page fault on a DAX file + * dax_iomap_fault - handle a page fault on a DAX file * @vma: The virtual memory area where the fault occurred * @vmf: The description of the fault * @ops: iomap ops passed from the file system @@ -1365,7 +1257,7 @@ EXPORT_SYMBOL_GPL(iomap_dax_rw); * or mkwrite handler for DAX files. Assumes the caller has done all the * necessary locking for the page fault to proceed successfully. */ -int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, +int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, struct iomap_ops *ops) { struct address_space *mapping = vma->vm_file->f_mapping; @@ -1374,8 +1266,9 @@ int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; sector_t sector; struct iomap iomap = { 0 }; - unsigned flags = 0; + unsigned flags = IOMAP_FAULT; int error, major = 0; + int locked_status = 0; void *entry; /* @@ -1386,7 +1279,7 @@ int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, if (pos >= i_size_read(inode)) return VM_FAULT_SIGBUS; - entry = grab_mapping_entry(mapping, vmf->pgoff); + entry = grab_mapping_entry(mapping, vmf->pgoff, 0); if (IS_ERR(entry)) { error = PTR_ERR(entry); goto out; @@ -1405,10 +1298,10 @@ int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, goto unlock_entry; if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { error = -EIO; /* fs corruption? */ - goto unlock_entry; + goto finish_iomap; } - sector = iomap.blkno + (((pos & PAGE_MASK) - iomap.offset) >> 9); + sector = dax_iomap_sector(&iomap, pos); if (vmf->cow_page) { switch (iomap.type) { @@ -1427,13 +1320,15 @@ int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } if (error) - goto unlock_entry; + goto finish_iomap; if (!radix_tree_exceptional_entry(entry)) { vmf->page = entry; - return VM_FAULT_LOCKED; + locked_status = VM_FAULT_LOCKED; + } else { + vmf->entry = entry; + locked_status = VM_FAULT_DAX_LOCKED; } - vmf->entry = entry; - return VM_FAULT_DAX_LOCKED; + goto finish_iomap; } switch (iomap.type) { @@ -1448,8 +1343,10 @@ int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, break; case IOMAP_UNWRITTEN: case IOMAP_HOLE: - if (!(vmf->flags & FAULT_FLAG_WRITE)) - return dax_load_hole(mapping, entry, vmf); + if (!(vmf->flags & FAULT_FLAG_WRITE)) { + locked_status = dax_load_hole(mapping, entry, vmf); + break; + } /*FALLTHRU*/ default: WARN_ON_ONCE(1); @@ -1457,15 +1354,218 @@ int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, break; } + finish_iomap: + if (ops->iomap_end) { + if (error) { + /* keep previous error */ + ops->iomap_end(inode, pos, PAGE_SIZE, 0, flags, + &iomap); + } else { + error = ops->iomap_end(inode, pos, PAGE_SIZE, + PAGE_SIZE, flags, &iomap); + } + } unlock_entry: - put_locked_mapping_entry(mapping, vmf->pgoff, entry); + if (!locked_status || error) + put_locked_mapping_entry(mapping, vmf->pgoff, entry); out: if (error == -ENOMEM) return VM_FAULT_OOM | major; /* -EBUSY is fine, somebody else faulted on the same PTE */ if (error < 0 && error != -EBUSY) return VM_FAULT_SIGBUS | major; + if (locked_status) { + WARN_ON_ONCE(error); /* -EBUSY from ops->iomap_end? */ + return locked_status; + } return VM_FAULT_NOPAGE | major; } -EXPORT_SYMBOL_GPL(iomap_dax_fault); +EXPORT_SYMBOL_GPL(dax_iomap_fault); + +#ifdef CONFIG_FS_DAX_PMD +/* + * The 'colour' (ie low bits) within a PMD of a page offset. This comes up + * more often than one might expect in the below functions. + */ +#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) + +static int dax_pmd_insert_mapping(struct vm_area_struct *vma, pmd_t *pmd, + struct vm_fault *vmf, unsigned long address, + struct iomap *iomap, loff_t pos, bool write, void **entryp) +{ + struct address_space *mapping = vma->vm_file->f_mapping; + struct block_device *bdev = iomap->bdev; + struct blk_dax_ctl dax = { + .sector = dax_iomap_sector(iomap, pos), + .size = PMD_SIZE, + }; + long length = dax_map_atomic(bdev, &dax); + void *ret; + + if (length < 0) /* dax_map_atomic() failed */ + return VM_FAULT_FALLBACK; + if (length < PMD_SIZE) + goto unmap_fallback; + if (pfn_t_to_pfn(dax.pfn) & PG_PMD_COLOUR) + goto unmap_fallback; + if (!pfn_t_devmap(dax.pfn)) + goto unmap_fallback; + + dax_unmap_atomic(bdev, &dax); + + ret = dax_insert_mapping_entry(mapping, vmf, *entryp, dax.sector, + RADIX_DAX_PMD); + if (IS_ERR(ret)) + return VM_FAULT_FALLBACK; + *entryp = ret; + + return vmf_insert_pfn_pmd(vma, address, pmd, dax.pfn, write); + + unmap_fallback: + dax_unmap_atomic(bdev, &dax); + return VM_FAULT_FALLBACK; +} + +static int dax_pmd_load_hole(struct vm_area_struct *vma, pmd_t *pmd, + struct vm_fault *vmf, unsigned long address, + struct iomap *iomap, void **entryp) +{ + struct address_space *mapping = vma->vm_file->f_mapping; + unsigned long pmd_addr = address & PMD_MASK; + struct page *zero_page; + spinlock_t *ptl; + pmd_t pmd_entry; + void *ret; + + zero_page = mm_get_huge_zero_page(vma->vm_mm); + + if (unlikely(!zero_page)) + return VM_FAULT_FALLBACK; + + ret = dax_insert_mapping_entry(mapping, vmf, *entryp, 0, + RADIX_DAX_PMD | RADIX_DAX_HZP); + if (IS_ERR(ret)) + return VM_FAULT_FALLBACK; + *entryp = ret; + + ptl = pmd_lock(vma->vm_mm, pmd); + if (!pmd_none(*pmd)) { + spin_unlock(ptl); + return VM_FAULT_FALLBACK; + } + + pmd_entry = mk_pmd(zero_page, vma->vm_page_prot); + pmd_entry = pmd_mkhuge(pmd_entry); + set_pmd_at(vma->vm_mm, pmd_addr, pmd, pmd_entry); + spin_unlock(ptl); + return VM_FAULT_NOPAGE; +} + +int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmd, unsigned int flags, struct iomap_ops *ops) +{ + struct address_space *mapping = vma->vm_file->f_mapping; + unsigned long pmd_addr = address & PMD_MASK; + bool write = flags & FAULT_FLAG_WRITE; + unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; + struct inode *inode = mapping->host; + int result = VM_FAULT_FALLBACK; + struct iomap iomap = { 0 }; + pgoff_t max_pgoff, pgoff; + struct vm_fault vmf; + void *entry; + loff_t pos; + int error; + + /* Fall back to PTEs if we're going to COW */ + if (write && !(vma->vm_flags & VM_SHARED)) + goto fallback; + + /* If the PMD would extend outside the VMA */ + if (pmd_addr < vma->vm_start) + goto fallback; + if ((pmd_addr + PMD_SIZE) > vma->vm_end) + goto fallback; + + /* + * Check whether offset isn't beyond end of file now. Caller is + * supposed to hold locks serializing us with truncate / punch hole so + * this is a reliable test. + */ + pgoff = linear_page_index(vma, pmd_addr); + max_pgoff = (i_size_read(inode) - 1) >> PAGE_SHIFT; + + if (pgoff > max_pgoff) + return VM_FAULT_SIGBUS; + + /* If the PMD would extend beyond the file size */ + if ((pgoff | PG_PMD_COLOUR) > max_pgoff) + goto fallback; + + /* + * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX + * PMD or a HZP entry. If it can't (because a 4k page is already in + * the tree, for instance), it will return -EEXIST and we just fall + * back to 4k entries. + */ + entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); + if (IS_ERR(entry)) + goto fallback; + + /* + * Note that we don't use iomap_apply here. We aren't doing I/O, only + * setting up a mapping, so really we're using iomap_begin() as a way + * to look up our filesystem block. + */ + pos = (loff_t)pgoff << PAGE_SHIFT; + error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); + if (error) + goto unlock_entry; + if (iomap.offset + iomap.length < pos + PMD_SIZE) + goto finish_iomap; + + vmf.pgoff = pgoff; + vmf.flags = flags; + vmf.gfp_mask = mapping_gfp_mask(mapping) | __GFP_IO; + + switch (iomap.type) { + case IOMAP_MAPPED: + result = dax_pmd_insert_mapping(vma, pmd, &vmf, address, + &iomap, pos, write, &entry); + break; + case IOMAP_UNWRITTEN: + case IOMAP_HOLE: + if (WARN_ON_ONCE(write)) + goto finish_iomap; + result = dax_pmd_load_hole(vma, pmd, &vmf, address, &iomap, + &entry); + break; + default: + WARN_ON_ONCE(1); + break; + } + + finish_iomap: + if (ops->iomap_end) { + if (result == VM_FAULT_FALLBACK) { + ops->iomap_end(inode, pos, PMD_SIZE, 0, iomap_flags, + &iomap); + } else { + error = ops->iomap_end(inode, pos, PMD_SIZE, PMD_SIZE, + iomap_flags, &iomap); + if (error) + result = VM_FAULT_FALLBACK; + } + } + unlock_entry: + put_locked_mapping_entry(mapping, pgoff, entry); + fallback: + if (result == VM_FAULT_FALLBACK) { + split_huge_pmd(vma, pmd, address); + count_vm_event(THP_FAULT_FALLBACK); + } + return result; +} +EXPORT_SYMBOL_GPL(dax_iomap_pmd_fault); +#endif /* CONFIG_FS_DAX_PMD */ #endif /* CONFIG_FS_IOMAP */ diff --git a/fs/ext2/file.c b/fs/ext2/file.c index a0e1478dfd04..b0f241528a30 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -38,7 +38,7 @@ static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) return 0; /* skip atime */ inode_lock_shared(inode); - ret = iomap_dax_rw(iocb, to, &ext2_iomap_ops); + ret = dax_iomap_rw(iocb, to, &ext2_iomap_ops); inode_unlock_shared(inode); file_accessed(iocb->ki_filp); @@ -62,7 +62,7 @@ static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) if (ret) goto out_unlock; - ret = iomap_dax_rw(iocb, from, &ext2_iomap_ops); + ret = dax_iomap_rw(iocb, from, &ext2_iomap_ops); if (ret > 0 && iocb->ki_pos > i_size_read(inode)) { i_size_write(inode, iocb->ki_pos); mark_inode_dirty(inode); @@ -99,7 +99,7 @@ static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) } down_read(&ei->dax_sem); - ret = iomap_dax_fault(vma, vmf, &ext2_iomap_ops); + ret = dax_iomap_fault(vma, vmf, &ext2_iomap_ops); up_read(&ei->dax_sem); if (vmf->flags & FAULT_FLAG_WRITE) @@ -107,27 +107,6 @@ static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) return ret; } -static int ext2_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, - pmd_t *pmd, unsigned int flags) -{ - struct inode *inode = file_inode(vma->vm_file); - struct ext2_inode_info *ei = EXT2_I(inode); - int ret; - - if (flags & FAULT_FLAG_WRITE) { - sb_start_pagefault(inode->i_sb); - file_update_time(vma->vm_file); - } - down_read(&ei->dax_sem); - - ret = dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block); - - up_read(&ei->dax_sem); - if (flags & FAULT_FLAG_WRITE) - sb_end_pagefault(inode->i_sb); - return ret; -} - static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) { @@ -154,7 +133,11 @@ static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma, static const struct vm_operations_struct ext2_dax_vm_ops = { .fault = ext2_dax_fault, - .pmd_fault = ext2_dax_pmd_fault, + /* + * .pmd_fault is not supported for DAX because allocation in ext2 + * cannot be reliably aligned to huge page sizes and so pmd faults + * will always fail and fail back to regular faults. + */ .page_mkwrite = ext2_dax_fault, .pfn_mkwrite = ext2_dax_pfn_mkwrite, }; @@ -166,7 +149,7 @@ static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) file_accessed(file); vma->vm_ops = &ext2_dax_vm_ops; - vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; + vma->vm_flags |= VM_MIXEDMAP; return 0; } #else diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9c064727ed62..3d58b2b477e8 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -767,6 +767,9 @@ static int _ext4_get_block(struct inode *inode, sector_t iblock, ext4_update_bh_state(bh, map.m_flags); bh->b_size = inode->i_sb->s_blocksize * map.m_len; ret = 0; + } else if (ret == 0) { + /* hole case, need to fill in bh->b_size */ + bh->b_size = inode->i_sb->s_blocksize * map.m_len; } return ret; } diff --git a/fs/iomap.c b/fs/iomap.c index a8ee8c33ca78..13dd413b2b9c 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -467,8 +467,9 @@ int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, offset = page_offset(page); while (length > 0) { - ret = iomap_apply(inode, offset, length, IOMAP_WRITE, - ops, page, iomap_page_mkwrite_actor); + ret = iomap_apply(inode, offset, length, + IOMAP_WRITE | IOMAP_FAULT, ops, page, + iomap_page_mkwrite_actor); if (unlikely(ret <= 0)) goto out_unlock; offset += ret; diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 3e57a56cf829..561cf1456c6c 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1298,8 +1298,7 @@ __xfs_get_blocks( sector_t iblock, struct buffer_head *bh_result, int create, - bool direct, - bool dax_fault) + bool direct) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; @@ -1420,13 +1419,8 @@ __xfs_get_blocks( if (ISUNWRITTEN(&imap)) set_buffer_unwritten(bh_result); /* direct IO needs special help */ - if (create) { - if (dax_fault) - ASSERT(!ISUNWRITTEN(&imap)); - else - xfs_map_direct(inode, bh_result, &imap, offset, - is_cow); - } + if (create) + xfs_map_direct(inode, bh_result, &imap, offset, is_cow); } /* @@ -1466,7 +1460,7 @@ xfs_get_blocks( struct buffer_head *bh_result, int create) { - return __xfs_get_blocks(inode, iblock, bh_result, create, false, false); + return __xfs_get_blocks(inode, iblock, bh_result, create, false); } int @@ -1476,17 +1470,7 @@ xfs_get_blocks_direct( struct buffer_head *bh_result, int create) { - return __xfs_get_blocks(inode, iblock, bh_result, create, true, false); -} - -int -xfs_get_blocks_dax_fault( - struct inode *inode, - sector_t iblock, - struct buffer_head *bh_result, - int create) -{ - return __xfs_get_blocks(inode, iblock, bh_result, create, true, true); + return __xfs_get_blocks(inode, iblock, bh_result, create, true); } /* diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h index b3c6634f9518..34dc00dfb91d 100644 --- a/fs/xfs/xfs_aops.h +++ b/fs/xfs/xfs_aops.h @@ -59,9 +59,6 @@ int xfs_get_blocks(struct inode *inode, sector_t offset, struct buffer_head *map_bh, int create); int xfs_get_blocks_direct(struct inode *inode, sector_t offset, struct buffer_head *map_bh, int create); -int xfs_get_blocks_dax_fault(struct inode *inode, sector_t offset, - struct buffer_head *map_bh, int create); - int xfs_end_io_direct_write(struct kiocb *iocb, loff_t offset, ssize_t size, void *private); int xfs_setfilesize(struct xfs_inode *ip, xfs_off_t offset, size_t size); diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 6e4f7f900fea..d818c160451f 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -318,7 +318,7 @@ xfs_file_dax_read( return 0; /* skip atime */ xfs_rw_ilock(ip, XFS_IOLOCK_SHARED); - ret = iomap_dax_rw(iocb, to, &xfs_iomap_ops); + ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops); xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); file_accessed(iocb->ki_filp); @@ -653,7 +653,7 @@ xfs_file_dax_write( trace_xfs_file_dax_write(ip, count, pos); - ret = iomap_dax_rw(iocb, from, &xfs_iomap_ops); + ret = dax_iomap_rw(iocb, from, &xfs_iomap_ops); if (ret > 0 && iocb->ki_pos > i_size_read(inode)) { i_size_write(inode, iocb->ki_pos); error = xfs_setfilesize(ip, pos, ret); @@ -1474,7 +1474,7 @@ xfs_filemap_page_mkwrite( xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); if (IS_DAX(inode)) { - ret = iomap_dax_fault(vma, vmf, &xfs_iomap_ops); + ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops); } else { ret = iomap_page_mkwrite(vma, vmf, &xfs_iomap_ops); ret = block_page_mkwrite_return(ret); @@ -1508,7 +1508,7 @@ xfs_filemap_fault( * changes to xfs_get_blocks_direct() to map unwritten extent * ioend for conversion on read-only mappings. */ - ret = iomap_dax_fault(vma, vmf, &xfs_iomap_ops); + ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops); } else ret = filemap_fault(vma, vmf); xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); @@ -1545,7 +1545,7 @@ xfs_filemap_pmd_fault( } xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); - ret = dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_dax_fault); + ret = dax_iomap_pmd_fault(vma, addr, pmd, flags, &xfs_iomap_ops); xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); if (flags & FAULT_FLAG_WRITE) diff --git a/include/linux/dax.h b/include/linux/dax.h index add6c4bc568f..8d1a5c47945f 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -8,21 +8,46 @@ struct iomap_ops; -/* We use lowest available exceptional entry bit for locking */ +/* + * We use lowest available bit in exceptional entry for locking, one bit for + * the entry size (PMD) and two more to tell us if the entry is a huge zero + * page (HZP) or an empty entry that is just used for locking. In total four + * special bits. + * + * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the HZP and + * EMPTY bits aren't set the entry is a normal DAX entry with a filesystem + * block allocation. + */ +#define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4) #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT) +#define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) +#define RADIX_DAX_HZP (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) +#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) -ssize_t iomap_dax_rw(struct kiocb *iocb, struct iov_iter *iter, +static inline unsigned long dax_radix_sector(void *entry) +{ + return (unsigned long)entry >> RADIX_DAX_SHIFT; +} + +static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags) +{ + return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | + ((unsigned long)sector << RADIX_DAX_SHIFT) | + RADIX_DAX_ENTRY_LOCK); +} + +ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, struct iomap_ops *ops); ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, get_block_t, dio_iodone_t, int flags); int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t); int dax_truncate_page(struct inode *, loff_t from, get_block_t); -int iomap_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, +int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, struct iomap_ops *ops); int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t); int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); void dax_wake_mapping_entry_waiter(struct address_space *mapping, - pgoff_t index, bool wake_all); + pgoff_t index, void *entry, bool wake_all); #ifdef CONFIG_FS_DAX struct page *read_dax_sector(struct block_device *bdev, sector_t n); @@ -48,15 +73,32 @@ static inline int __dax_zero_page_range(struct block_device *bdev, } #endif -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) -int dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *, - unsigned int flags, get_block_t); -#else static inline int dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags, get_block_t gb) { return VM_FAULT_FALLBACK; } + +#ifdef CONFIG_FS_DAX_PMD +static inline unsigned int dax_radix_order(void *entry) +{ + if ((unsigned long)entry & RADIX_DAX_PMD) + return PMD_SHIFT - PAGE_SHIFT; + return 0; +} +int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmd, unsigned int flags, struct iomap_ops *ops); +#else +static inline unsigned int dax_radix_order(void *entry) +{ + return 0; +} +static inline int dax_iomap_pmd_fault(struct vm_area_struct *vma, + unsigned long address, pmd_t *pmd, unsigned int flags, + struct iomap_ops *ops) +{ + return VM_FAULT_FALLBACK; +} #endif int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *); #define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb) diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 7892f55a1866..f185156de74d 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -49,6 +49,7 @@ struct iomap { #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */ #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */ #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */ +#define IOMAP_FAULT (1 << 3) /* mapping for page fault */ struct iomap_ops { /* diff --git a/mm/filemap.c b/mm/filemap.c index c7fe2f16503f..db26ebc6c62f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -137,13 +137,12 @@ static int page_cache_tree_insert(struct address_space *mapping, } else { /* DAX can replace empty locked entry with a hole */ WARN_ON_ONCE(p != - (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | - RADIX_DAX_ENTRY_LOCK)); + dax_radix_locked_entry(0, RADIX_DAX_EMPTY)); /* DAX accounts exceptional entries as normal pages */ if (node) workingset_node_pages_dec(node); /* Wakeup waiters for exceptional entry lock */ - dax_wake_mapping_entry_waiter(mapping, page->index, + dax_wake_mapping_entry_waiter(mapping, page->index, p, false); } } |